VFS: security/: d_backing_inode() annotations

[mirror_ubuntu-hirsute-kernel.git] / security / selinux / hooks.c

/*
 *  NSA Security-Enhanced Linux (SELinux) security module
 *
 *  This file contains the SELinux hook function implementations.
 *
 *  Authors:  Stephen Smalley, <sds@epoch.ncsc.mil>
 *            Chris Vance, <cvance@nai.com>
 *            Wayne Salamon, <wsalamon@nai.com>
 *            James Morris <jmorris@redhat.com>
 *
 *  Copyright (C) 2001,2002 Networks Associates Technology, Inc.
 *  Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
 *                                         Eric Paris <eparis@redhat.com>
 *  Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
 *                          <dgoeddel@trustedcs.com>
 *  Copyright (C) 2006, 2007, 2009 Hewlett-Packard Development Company, L.P.
 *      Paul Moore <paul@paul-moore.com>
 *  Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
 *                     Yuichi Nakamura <ynakam@hitachisoft.jp>
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License version 2,
 *      as published by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/kd.h>
#include <linux/kernel.h>
#include <linux/tracehook.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/xattr.h>
#include <linux/capability.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
#include <linux/swap.h>
#include <linux/spinlock.h>
#include <linux/syscalls.h>
#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/tty.h>
#include <net/icmp.h>
#include <net/ip.h>             /* for local_port_range[] */
#include <net/tcp.h>            /* struct or_callable used in sock_rcv_skb */
#include <net/inet_connection_sock.h>
#include <net/net_namespace.h>
#include <net/netlabel.h>
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>    /* for network interface checks */
#include <net/netlink.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/quota.h>
#include <linux/un.h>           /* for Unix socket types */
#include <net/af_unix.h>        /* for Unix socket types */
#include <linux/parser.h>
#include <linux/nfs_mount.h>
#include <net/ipv6.h>
#include <linux/hugetlb.h>
#include <linux/personality.h>
#include <linux/audit.h>
#include <linux/string.h>
#include <linux/selinux.h>
#include <linux/mutex.h>
#include <linux/posix-timers.h>
#include <linux/syslog.h>
#include <linux/user_namespace.h>
#include <linux/export.h>
#include <linux/msg.h>
#include <linux/shm.h>

#include "avc.h"
#include "objsec.h"
#include "netif.h"
#include "netnode.h"
#include "netport.h"
#include "xfrm.h"
#include "netlabel.h"
#include "audit.h"
#include "avc_ss.h"

/* SECMARK reference count */
static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);

#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
int selinux_enforcing;

static int __init enforcing_setup(char *str)
{
        unsigned long enforcing;
        if (!kstrtoul(str, 0, &enforcing))
                selinux_enforcing = enforcing ? 1 : 0;
        return 1;
}
__setup("enforcing=", enforcing_setup);
#endif

#ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;

static int __init selinux_enabled_setup(char *str)
{
        unsigned long enabled;
        if (!kstrtoul(str, 0, &enabled))
                selinux_enabled = enabled ? 1 : 0;
        return 1;
}
__setup("selinux=", selinux_enabled_setup);
#else
int selinux_enabled = 1;
#endif

static struct kmem_cache *sel_inode_cache;

/**
 * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
 *
 * Description:
 * This function checks the SECMARK reference counter to see if any SECMARK
 * targets are currently configured, if the reference counter is greater than
 * zero SECMARK is considered to be enabled.  Returns true (1) if SECMARK is
 * enabled, false (0) if SECMARK is disabled.  If the always_check_network
 * policy capability is enabled, SECMARK is always considered enabled.
 *
 */
static int selinux_secmark_enabled(void)
{
        return (selinux_policycap_alwaysnetwork || atomic_read(&selinux_secmark_refcount));
}

/**
 * selinux_peerlbl_enabled - Check to see if peer labeling is currently enabled
 *
 * Description:
 * This function checks if NetLabel or labeled IPSEC is enabled.  Returns true
 * (1) if any are enabled or false (0) if neither are enabled.  If the
 * always_check_network policy capability is enabled, peer labeling
 * is always considered enabled.
 *
 */
static int selinux_peerlbl_enabled(void)
{
        return (selinux_policycap_alwaysnetwork || netlbl_enabled() || selinux_xfrm_enabled());
}

static int selinux_netcache_avc_callback(u32 event)
{
        if (event == AVC_CALLBACK_RESET) {
                sel_netif_flush();
                sel_netnode_flush();
                sel_netport_flush();
                synchronize_net();
        }
        return 0;
}

/*
 * initialise the security for the init task
 */
static void cred_init_security(void)
{
        struct cred *cred = (struct cred *) current->real_cred;
        struct task_security_struct *tsec;

        tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
        if (!tsec)
                panic("SELinux:  Failed to initialize initial task.\n");

        tsec->osid = tsec->sid = SECINITSID_KERNEL;
        cred->security = tsec;
}

/*
 * get the security ID of a set of credentials
 */
static inline u32 cred_sid(const struct cred *cred)
{
        const struct task_security_struct *tsec;

        tsec = cred->security;
        return tsec->sid;
}

/*
 * get the objective security ID of a task
 */
static inline u32 task_sid(const struct task_struct *task)
{
        u32 sid;

        rcu_read_lock();
        sid = cred_sid(__task_cred(task));
        rcu_read_unlock();
        return sid;
}

/*
 * get the subjective security ID of the current task
 */
static inline u32 current_sid(void)
{
        const struct task_security_struct *tsec = current_security();

        return tsec->sid;
}

/* Allocate and free functions for each kind of security blob. */

static int inode_alloc_security(struct inode *inode)
{
        struct inode_security_struct *isec;
        u32 sid = current_sid();

        isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
        if (!isec)
                return -ENOMEM;

        mutex_init(&isec->lock);
        INIT_LIST_HEAD(&isec->list);
        isec->inode = inode;
        isec->sid = SECINITSID_UNLABELED;
        isec->sclass = SECCLASS_FILE;
        isec->task_sid = sid;
        inode->i_security = isec;

        return 0;
}

static void inode_free_rcu(struct rcu_head *head)
{
        struct inode_security_struct *isec;

        isec = container_of(head, struct inode_security_struct, rcu);
        kmem_cache_free(sel_inode_cache, isec);
}

static void inode_free_security(struct inode *inode)
{
        struct inode_security_struct *isec = inode->i_security;
        struct superblock_security_struct *sbsec = inode->i_sb->s_security;

        spin_lock(&sbsec->isec_lock);
        if (!list_empty(&isec->list))
                list_del_init(&isec->list);
        spin_unlock(&sbsec->isec_lock);

        /*
         * The inode may still be referenced in a path walk and
         * a call to selinux_inode_permission() can be made
         * after inode_free_security() is called. Ideally, the VFS
         * wouldn't do this, but fixing that is a much harder
         * job. For now, simply free the i_security via RCU, and
         * leave the current inode->i_security pointer intact.
         * The inode will be freed after the RCU grace period too.
         */
        call_rcu(&isec->rcu, inode_free_rcu);
}

static int file_alloc_security(struct file *file)
{
        struct file_security_struct *fsec;
        u32 sid = current_sid();

        fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
        if (!fsec)
                return -ENOMEM;

        fsec->sid = sid;
        fsec->fown_sid = sid;
        file->f_security = fsec;

        return 0;
}

static void file_free_security(struct file *file)
{
        struct file_security_struct *fsec = file->f_security;
        file->f_security = NULL;
        kfree(fsec);
}

static int superblock_alloc_security(struct super_block *sb)
{
        struct superblock_security_struct *sbsec;

        sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
        if (!sbsec)
                return -ENOMEM;

        mutex_init(&sbsec->lock);
        INIT_LIST_HEAD(&sbsec->isec_head);
        spin_lock_init(&sbsec->isec_lock);
        sbsec->sb = sb;
        sbsec->sid = SECINITSID_UNLABELED;
        sbsec->def_sid = SECINITSID_FILE;
        sbsec->mntpoint_sid = SECINITSID_UNLABELED;
        sb->s_security = sbsec;

        return 0;
}

static void superblock_free_security(struct super_block *sb)
{
        struct superblock_security_struct *sbsec = sb->s_security;
        sb->s_security = NULL;
        kfree(sbsec);
}

/* The file system's label must be initialized prior to use. */

static const char *labeling_behaviors[7] = {
        "uses xattr",
        "uses transition SIDs",
        "uses task SIDs",
        "uses genfs_contexts",
        "not configured for labeling",
        "uses mountpoint labeling",
        "uses native labeling",
};

static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);

static inline int inode_doinit(struct inode *inode)
{
        return inode_doinit_with_dentry(inode, NULL);
}

enum {
        Opt_error = -1,
        Opt_context = 1,
        Opt_fscontext = 2,
        Opt_defcontext = 3,
        Opt_rootcontext = 4,
        Opt_labelsupport = 5,
        Opt_nextmntopt = 6,
};

#define NUM_SEL_MNT_OPTS        (Opt_nextmntopt - 1)

static const match_table_t tokens = {
        {Opt_context, CONTEXT_STR "%s"},
        {Opt_fscontext, FSCONTEXT_STR "%s"},
        {Opt_defcontext, DEFCONTEXT_STR "%s"},
        {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
        {Opt_labelsupport, LABELSUPP_STR},
        {Opt_error, NULL},
};

#define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"

static int may_context_mount_sb_relabel(u32 sid,
                        struct superblock_security_struct *sbsec,
                        const struct cred *cred)
{
        const struct task_security_struct *tsec = cred->security;
        int rc;

        rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
                          FILESYSTEM__RELABELFROM, NULL);
        if (rc)
                return rc;

        rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
                          FILESYSTEM__RELABELTO, NULL);
        return rc;
}

static int may_context_mount_inode_relabel(u32 sid,
                        struct superblock_security_struct *sbsec,
                        const struct cred *cred)
{
        const struct task_security_struct *tsec = cred->security;
        int rc;
        rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
                          FILESYSTEM__RELABELFROM, NULL);
        if (rc)
                return rc;

        rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
                          FILESYSTEM__ASSOCIATE, NULL);
        return rc;
}

static int selinux_is_sblabel_mnt(struct super_block *sb)
{
        struct superblock_security_struct *sbsec = sb->s_security;

        return sbsec->behavior == SECURITY_FS_USE_XATTR ||
                sbsec->behavior == SECURITY_FS_USE_TRANS ||
                sbsec->behavior == SECURITY_FS_USE_TASK ||
                /* Special handling. Genfs but also in-core setxattr handler */
                !strcmp(sb->s_type->name, "sysfs") ||
                !strcmp(sb->s_type->name, "pstore") ||
                !strcmp(sb->s_type->name, "debugfs") ||
                !strcmp(sb->s_type->name, "rootfs");
}

static int sb_finish_set_opts(struct super_block *sb)
{
        struct superblock_security_struct *sbsec = sb->s_security;
        struct dentry *root = sb->s_root;
        struct inode *root_inode = d_backing_inode(root);
        int rc = 0;

        if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
                /* Make sure that the xattr handler exists and that no
                   error other than -ENODATA is returned by getxattr on
                   the root directory.  -ENODATA is ok, as this may be
                   the first boot of the SELinux kernel before we have
                   assigned xattr values to the filesystem. */
                if (!root_inode->i_op->getxattr) {
                        printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
                               "xattr support\n", sb->s_id, sb->s_type->name);
                        rc = -EOPNOTSUPP;
                        goto out;
                }
                rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0);
                if (rc < 0 && rc != -ENODATA) {
                        if (rc == -EOPNOTSUPP)
                                printk(KERN_WARNING "SELinux: (dev %s, type "
                                       "%s) has no security xattr handler\n",
                                       sb->s_id, sb->s_type->name);
                        else
                                printk(KERN_WARNING "SELinux: (dev %s, type "
                                       "%s) getxattr errno %d\n", sb->s_id,
                                       sb->s_type->name, -rc);
                        goto out;
                }
        }

        if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
                printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
                       sb->s_id, sb->s_type->name);

        sbsec->flags |= SE_SBINITIALIZED;
        if (selinux_is_sblabel_mnt(sb))
                sbsec->flags |= SBLABEL_MNT;

        /* Initialize the root inode. */
        rc = inode_doinit_with_dentry(root_inode, root);

        /* Initialize any other inodes associated with the superblock, e.g.
           inodes created prior to initial policy load or inodes created
           during get_sb by a pseudo filesystem that directly
           populates itself. */
        spin_lock(&sbsec->isec_lock);
next_inode:
        if (!list_empty(&sbsec->isec_head)) {
                struct inode_security_struct *isec =
                                list_entry(sbsec->isec_head.next,
                                           struct inode_security_struct, list);
                struct inode *inode = isec->inode;
                list_del_init(&isec->list);
                spin_unlock(&sbsec->isec_lock);
                inode = igrab(inode);
                if (inode) {
                        if (!IS_PRIVATE(inode))
                                inode_doinit(inode);
                        iput(inode);
                }
                spin_lock(&sbsec->isec_lock);
                goto next_inode;
        }
        spin_unlock(&sbsec->isec_lock);
out:
        return rc;
}

/*
 * This function should allow an FS to ask what it's mount security
 * options were so it can use those later for submounts, displaying
 * mount options, or whatever.
 */
static int selinux_get_mnt_opts(const struct super_block *sb,
                                struct security_mnt_opts *opts)
{
        int rc = 0, i;
        struct superblock_security_struct *sbsec = sb->s_security;
        char *context = NULL;
        u32 len;
        char tmp;

        security_init_mnt_opts(opts);

        if (!(sbsec->flags & SE_SBINITIALIZED))
                return -EINVAL;

        if (!ss_initialized)
                return -EINVAL;

        /* make sure we always check enough bits to cover the mask */
        BUILD_BUG_ON(SE_MNTMASK >= (1 << NUM_SEL_MNT_OPTS));

        tmp = sbsec->flags & SE_MNTMASK;
        /* count the number of mount options for this sb */
        for (i = 0; i < NUM_SEL_MNT_OPTS; i++) {
                if (tmp & 0x01)
                        opts->num_mnt_opts++;
                tmp >>= 1;
        }
        /* Check if the Label support flag is set */
        if (sbsec->flags & SBLABEL_MNT)
                opts->num_mnt_opts++;

        opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
        if (!opts->mnt_opts) {
                rc = -ENOMEM;
                goto out_free;
        }

        opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
        if (!opts->mnt_opts_flags) {
                rc = -ENOMEM;
                goto out_free;
        }

        i = 0;
        if (sbsec->flags & FSCONTEXT_MNT) {
                rc = security_sid_to_context(sbsec->sid, &context, &len);
                if (rc)
                        goto out_free;
                opts->mnt_opts[i] = context;
                opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
        }
        if (sbsec->flags & CONTEXT_MNT) {
                rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
                if (rc)
                        goto out_free;
                opts->mnt_opts[i] = context;
                opts->mnt_opts_flags[i++] = CONTEXT_MNT;
        }
        if (sbsec->flags & DEFCONTEXT_MNT) {
                rc = security_sid_to_context(sbsec->def_sid, &context, &len);
                if (rc)
                        goto out_free;
                opts->mnt_opts[i] = context;
                opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
        }
        if (sbsec->flags & ROOTCONTEXT_MNT) {
                struct inode *root = d_backing_inode(sbsec->sb->s_root);
                struct inode_security_struct *isec = root->i_security;

                rc = security_sid_to_context(isec->sid, &context, &len);
                if (rc)
                        goto out_free;
                opts->mnt_opts[i] = context;
                opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
        }
        if (sbsec->flags & SBLABEL_MNT) {
                opts->mnt_opts[i] = NULL;
                opts->mnt_opts_flags[i++] = SBLABEL_MNT;
        }

        BUG_ON(i != opts->num_mnt_opts);

        return 0;

out_free:
        security_free_mnt_opts(opts);
        return rc;
}

static int bad_option(struct superblock_security_struct *sbsec, char flag,
                      u32 old_sid, u32 new_sid)
{
        char mnt_flags = sbsec->flags & SE_MNTMASK;

        /* check if the old mount command had the same options */
        if (sbsec->flags & SE_SBINITIALIZED)
                if (!(sbsec->flags & flag) ||
                    (old_sid != new_sid))
                        return 1;

        /* check if we were passed the same options twice,
         * aka someone passed context=a,context=b
         */
        if (!(sbsec->flags & SE_SBINITIALIZED))
                if (mnt_flags & flag)
                        return 1;
        return 0;
}

/*
 * Allow filesystems with binary mount data to explicitly set mount point
 * labeling information.
 */
static int selinux_set_mnt_opts(struct super_block *sb,
                                struct security_mnt_opts *opts,
                                unsigned long kern_flags,
                                unsigned long *set_kern_flags)
{
        const struct cred *cred = current_cred();
        int rc = 0, i;
        struct superblock_security_struct *sbsec = sb->s_security;
        const char *name = sb->s_type->name;
        struct inode *inode = d_backing_inode(sbsec->sb->s_root);
        struct inode_security_struct *root_isec = inode->i_security;
        u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
        u32 defcontext_sid = 0;
        char **mount_options = opts->mnt_opts;
        int *flags = opts->mnt_opts_flags;
        int num_opts = opts->num_mnt_opts;

        mutex_lock(&sbsec->lock);

        if (!ss_initialized) {
                if (!num_opts) {
                        /* Defer initialization until selinux_complete_init,
                           after the initial policy is loaded and the security
                           server is ready to handle calls. */
                        goto out;
                }
                rc = -EINVAL;
                printk(KERN_WARNING "SELinux: Unable to set superblock options "
                        "before the security server is initialized\n");
                goto out;
        }
        if (kern_flags && !set_kern_flags) {
                /* Specifying internal flags without providing a place to
                 * place the results is not allowed */
                rc = -EINVAL;
                goto out;
        }

        /*
         * Binary mount data FS will come through this function twice.  Once
         * from an explicit call and once from the generic calls from the vfs.
         * Since the generic VFS calls will not contain any security mount data
         * we need to skip the double mount verification.
         *
         * This does open a hole in which we will not notice if the first
         * mount using this sb set explict options and a second mount using
         * this sb does not set any security options.  (The first options
         * will be used for both mounts)
         */
        if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
            && (num_opts == 0))
                goto out;

        /*
         * parse the mount options, check if they are valid sids.
         * also check if someone is trying to mount the same sb more
         * than once with different security options.
         */
        for (i = 0; i < num_opts; i++) {
                u32 sid;

                if (flags[i] == SBLABEL_MNT)
                        continue;
                rc = security_context_to_sid(mount_options[i],
                                             strlen(mount_options[i]), &sid, GFP_KERNEL);
                if (rc) {
                        printk(KERN_WARNING "SELinux: security_context_to_sid"
                               "(%s) failed for (dev %s, type %s) errno=%d\n",
                               mount_options[i], sb->s_id, name, rc);
                        goto out;
                }
                switch (flags[i]) {
                case FSCONTEXT_MNT:
                        fscontext_sid = sid;

                        if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
                                        fscontext_sid))
                                goto out_double_mount;

                        sbsec->flags |= FSCONTEXT_MNT;
                        break;
                case CONTEXT_MNT:
                        context_sid = sid;

                        if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
                                        context_sid))
                                goto out_double_mount;

                        sbsec->flags |= CONTEXT_MNT;
                        break;
                case ROOTCONTEXT_MNT:
                        rootcontext_sid = sid;

                        if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
                                        rootcontext_sid))
                                goto out_double_mount;

                        sbsec->flags |= ROOTCONTEXT_MNT;

                        break;
                case DEFCONTEXT_MNT:
                        defcontext_sid = sid;

                        if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
                                        defcontext_sid))
                                goto out_double_mount;

                        sbsec->flags |= DEFCONTEXT_MNT;

                        break;
                default:
                        rc = -EINVAL;
                        goto out;
                }
        }

        if (sbsec->flags & SE_SBINITIALIZED) {
                /* previously mounted with options, but not on this attempt? */
                if ((sbsec->flags & SE_MNTMASK) && !num_opts)
                        goto out_double_mount;
                rc = 0;
                goto out;
        }

        if (strcmp(sb->s_type->name, "proc") == 0)
                sbsec->flags |= SE_SBPROC;

        if (!sbsec->behavior) {
                /*
                 * Determine the labeling behavior to use for this
                 * filesystem type.
                 */
                rc = security_fs_use(sb);
                if (rc) {
                        printk(KERN_WARNING
                                "%s: security_fs_use(%s) returned %d\n",
                                        __func__, sb->s_type->name, rc);
                        goto out;
                }
        }
        /* sets the context of the superblock for the fs being mounted. */
        if (fscontext_sid) {
                rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
                if (rc)
                        goto out;

                sbsec->sid = fscontext_sid;
        }

        /*
         * Switch to using mount point labeling behavior.
         * sets the label used on all file below the mountpoint, and will set
         * the superblock context if not already set.
         */
        if (kern_flags & SECURITY_LSM_NATIVE_LABELS && !context_sid) {
                sbsec->behavior = SECURITY_FS_USE_NATIVE;
                *set_kern_flags |= SECURITY_LSM_NATIVE_LABELS;
        }

        if (context_sid) {
                if (!fscontext_sid) {
                        rc = may_context_mount_sb_relabel(context_sid, sbsec,
                                                          cred);
                        if (rc)
                                goto out;
                        sbsec->sid = context_sid;
                } else {
                        rc = may_context_mount_inode_relabel(context_sid, sbsec,
                                                             cred);
                        if (rc)
                                goto out;
                }
                if (!rootcontext_sid)
                        rootcontext_sid = context_sid;

                sbsec->mntpoint_sid = context_sid;
                sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
        }

        if (rootcontext_sid) {
                rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
                                                     cred);
                if (rc)
                        goto out;

                root_isec->sid = rootcontext_sid;
                root_isec->initialized = 1;
        }

        if (defcontext_sid) {
                if (sbsec->behavior != SECURITY_FS_USE_XATTR &&
                        sbsec->behavior != SECURITY_FS_USE_NATIVE) {
                        rc = -EINVAL;
                        printk(KERN_WARNING "SELinux: defcontext option is "
                               "invalid for this filesystem type\n");
                        goto out;
                }

                if (defcontext_sid != sbsec->def_sid) {
                        rc = may_context_mount_inode_relabel(defcontext_sid,
                                                             sbsec, cred);
                        if (rc)
                                goto out;
                }

                sbsec->def_sid = defcontext_sid;
        }

        rc = sb_finish_set_opts(sb);
out:
        mutex_unlock(&sbsec->lock);
        return rc;
out_double_mount:
        rc = -EINVAL;
        printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, different "
               "security settings for (dev %s, type %s)\n", sb->s_id, name);
        goto out;
}

static int selinux_cmp_sb_context(const struct super_block *oldsb,
                                    const struct super_block *newsb)
{
        struct superblock_security_struct *old = oldsb->s_security;
        struct superblock_security_struct *new = newsb->s_security;
        char oldflags = old->flags & SE_MNTMASK;
        char newflags = new->flags & SE_MNTMASK;

        if (oldflags != newflags)
                goto mismatch;
        if ((oldflags & FSCONTEXT_MNT) && old->sid != new->sid)
                goto mismatch;
        if ((oldflags & CONTEXT_MNT) && old->mntpoint_sid != new->mntpoint_sid)
                goto mismatch;
        if ((oldflags & DEFCONTEXT_MNT) && old->def_sid != new->def_sid)
                goto mismatch;
        if (oldflags & ROOTCONTEXT_MNT) {
                struct inode_security_struct *oldroot = d_backing_inode(oldsb->s_root)->i_security;
                struct inode_security_struct *newroot = d_backing_inode(newsb->s_root)->i_security;
                if (oldroot->sid != newroot->sid)
                        goto mismatch;
        }
        return 0;
mismatch:
        printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, "
                            "different security settings for (dev %s, "
                            "type %s)\n", newsb->s_id, newsb->s_type->name);
        return -EBUSY;
}

static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
                                        struct super_block *newsb)
{
        const struct superblock_security_struct *oldsbsec = oldsb->s_security;
        struct superblock_security_struct *newsbsec = newsb->s_security;

        int set_fscontext =     (oldsbsec->flags & FSCONTEXT_MNT);
        int set_context =       (oldsbsec->flags & CONTEXT_MNT);
        int set_rootcontext =   (oldsbsec->flags & ROOTCONTEXT_MNT);

        /*
         * if the parent was able to be mounted it clearly had no special lsm
         * mount options.  thus we can safely deal with this superblock later
         */
        if (!ss_initialized)
                return 0;

        /* how can we clone if the old one wasn't set up?? */
        BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));

        /* if fs is reusing a sb, make sure that the contexts match */
        if (newsbsec->flags & SE_SBINITIALIZED)
                return selinux_cmp_sb_context(oldsb, newsb);

        mutex_lock(&newsbsec->lock);

        newsbsec->flags = oldsbsec->flags;

        newsbsec->sid = oldsbsec->sid;
        newsbsec->def_sid = oldsbsec->def_sid;
        newsbsec->behavior = oldsbsec->behavior;

        if (set_context) {
                u32 sid = oldsbsec->mntpoint_sid;

                if (!set_fscontext)
                        newsbsec->sid = sid;
                if (!set_rootcontext) {
                        struct inode *newinode = d_backing_inode(newsb->s_root);
                        struct inode_security_struct *newisec = newinode->i_security;
                        newisec->sid = sid;
                }
                newsbsec->mntpoint_sid = sid;
        }
        if (set_rootcontext) {
                const struct inode *oldinode = d_backing_inode(oldsb->s_root);
                const struct inode_security_struct *oldisec = oldinode->i_security;
                struct inode *newinode = d_backing_inode(newsb->s_root);
                struct inode_security_struct *newisec = newinode->i_security;

                newisec->sid = oldisec->sid;
        }

        sb_finish_set_opts(newsb);
        mutex_unlock(&newsbsec->lock);
        return 0;
}

static int selinux_parse_opts_str(char *options,
                                  struct security_mnt_opts *opts)
{
        char *p;
        char *context = NULL, *defcontext = NULL;
        char *fscontext = NULL, *rootcontext = NULL;
        int rc, num_mnt_opts = 0;

        opts->num_mnt_opts = 0;

        /* Standard string-based options. */
        while ((p = strsep(&options, "|")) != NULL) {
                int token;
                substring_t args[MAX_OPT_ARGS];

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);

                switch (token) {
                case Opt_context:
                        if (context || defcontext) {
                                rc = -EINVAL;
                                printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                goto out_err;
                        }
                        context = match_strdup(&args[0]);
                        if (!context) {
                                rc = -ENOMEM;
                                goto out_err;
                        }
                        break;

                case Opt_fscontext:
                        if (fscontext) {
                                rc = -EINVAL;
                                printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                goto out_err;
                        }
                        fscontext = match_strdup(&args[0]);
                        if (!fscontext) {
                                rc = -ENOMEM;
                                goto out_err;
                        }
                        break;

                case Opt_rootcontext:
                        if (rootcontext) {
                                rc = -EINVAL;
                                printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                goto out_err;
                        }
                        rootcontext = match_strdup(&args[0]);
                        if (!rootcontext) {
                                rc = -ENOMEM;
                                goto out_err;
                        }
                        break;

                case Opt_defcontext:
                        if (context || defcontext) {
                                rc = -EINVAL;
                                printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
                                goto out_err;
                        }
                        defcontext = match_strdup(&args[0]);
                        if (!defcontext) {
                                rc = -ENOMEM;
                                goto out_err;
                        }
                        break;
                case Opt_labelsupport:
                        break;
                default:
                        rc = -EINVAL;
                        printk(KERN_WARNING "SELinux:  unknown mount option\n");
                        goto out_err;

                }
        }

        rc = -ENOMEM;
        opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
        if (!opts->mnt_opts)
                goto out_err;

        opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
        if (!opts->mnt_opts_flags) {
                kfree(opts->mnt_opts);
                goto out_err;
        }

        if (fscontext) {
                opts->mnt_opts[num_mnt_opts] = fscontext;
                opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
        }
        if (context) {
                opts->mnt_opts[num_mnt_opts] = context;
                opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
        }
        if (rootcontext) {
                opts->mnt_opts[num_mnt_opts] = rootcontext;
                opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
        }
        if (defcontext) {
                opts->mnt_opts[num_mnt_opts] = defcontext;
                opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
        }

        opts->num_mnt_opts = num_mnt_opts;
        return 0;

out_err:
        kfree(context);
        kfree(defcontext);
        kfree(fscontext);
        kfree(rootcontext);
        return rc;
}
/*
 * string mount options parsing and call set the sbsec
 */
static int superblock_doinit(struct super_block *sb, void *data)
{
        int rc = 0;
        char *options = data;
        struct security_mnt_opts opts;

        security_init_mnt_opts(&opts);

        if (!data)
                goto out;

        BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);

        rc = selinux_parse_opts_str(options, &opts);
        if (rc)
                goto out_err;

out:
        rc = selinux_set_mnt_opts(sb, &opts, 0, NULL);

out_err:
        security_free_mnt_opts(&opts);
        return rc;
}

static void selinux_write_opts(struct seq_file *m,
                               struct security_mnt_opts *opts)
{
        int i;
        char *prefix;

        for (i = 0; i < opts->num_mnt_opts; i++) {
                char *has_comma;

                if (opts->mnt_opts[i])
                        has_comma = strchr(opts->mnt_opts[i], ',');
                else
                        has_comma = NULL;

                switch (opts->mnt_opts_flags[i]) {
                case CONTEXT_MNT:
                        prefix = CONTEXT_STR;
                        break;
                case FSCONTEXT_MNT:
                        prefix = FSCONTEXT_STR;
                        break;
                case ROOTCONTEXT_MNT:
                        prefix = ROOTCONTEXT_STR;
                        break;
                case DEFCONTEXT_MNT:
                        prefix = DEFCONTEXT_STR;
                        break;
                case SBLABEL_MNT:
                        seq_putc(m, ',');
                        seq_puts(m, LABELSUPP_STR);
                        continue;
                default:
                        BUG();
                        return;
                };
                /* we need a comma before each option */
                seq_putc(m, ',');
                seq_puts(m, prefix);
                if (has_comma)
                        seq_putc(m, '\"');
                seq_puts(m, opts->mnt_opts[i]);
                if (has_comma)
                        seq_putc(m, '\"');
        }
}

static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
{
        struct security_mnt_opts opts;
        int rc;

        rc = selinux_get_mnt_opts(sb, &opts);
        if (rc) {
                /* before policy load we may get EINVAL, don't show anything */
                if (rc == -EINVAL)
                        rc = 0;
                return rc;
        }

        selinux_write_opts(m, &opts);

        security_free_mnt_opts(&opts);

        return rc;
}

static inline u16 inode_mode_to_security_class(umode_t mode)
{
        switch (mode & S_IFMT) {
        case S_IFSOCK:
                return SECCLASS_SOCK_FILE;
        case S_IFLNK:
                return SECCLASS_LNK_FILE;
        case S_IFREG:
                return SECCLASS_FILE;
        case S_IFBLK:
                return SECCLASS_BLK_FILE;
        case S_IFDIR:
                return SECCLASS_DIR;
        case S_IFCHR:
                return SECCLASS_CHR_FILE;
        case S_IFIFO:
                return SECCLASS_FIFO_FILE;

        }

        return SECCLASS_FILE;
}

static inline int default_protocol_stream(int protocol)
{
        return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
}

static inline int default_protocol_dgram(int protocol)
{
        return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
}

static inline u16 socket_type_to_security_class(int family, int type, int protocol)
{
        switch (family) {
        case PF_UNIX:
                switch (type) {
                case SOCK_STREAM:
                case SOCK_SEQPACKET:
                        return SECCLASS_UNIX_STREAM_SOCKET;
                case SOCK_DGRAM:
                        return SECCLASS_UNIX_DGRAM_SOCKET;
                }
                break;
        case PF_INET:
        case PF_INET6:
                switch (type) {
                case SOCK_STREAM:
                        if (default_protocol_stream(protocol))
                                return SECCLASS_TCP_SOCKET;
                        else
                                return SECCLASS_RAWIP_SOCKET;
                case SOCK_DGRAM:
                        if (default_protocol_dgram(protocol))
                                return SECCLASS_UDP_SOCKET;
                        else
                                return SECCLASS_RAWIP_SOCKET;
                case SOCK_DCCP:
                        return SECCLASS_DCCP_SOCKET;
                default:
                        return SECCLASS_RAWIP_SOCKET;
                }
                break;
        case PF_NETLINK:
                switch (protocol) {
                case NETLINK_ROUTE:
                        return SECCLASS_NETLINK_ROUTE_SOCKET;
                case NETLINK_FIREWALL:
                        return SECCLASS_NETLINK_FIREWALL_SOCKET;
                case NETLINK_SOCK_DIAG:
                        return SECCLASS_NETLINK_TCPDIAG_SOCKET;
                case NETLINK_NFLOG:
                        return SECCLASS_NETLINK_NFLOG_SOCKET;
                case NETLINK_XFRM:
                        return SECCLASS_NETLINK_XFRM_SOCKET;
                case NETLINK_SELINUX:
                        return SECCLASS_NETLINK_SELINUX_SOCKET;
                case NETLINK_AUDIT:
                        return SECCLASS_NETLINK_AUDIT_SOCKET;
                case NETLINK_IP6_FW:
                        return SECCLASS_NETLINK_IP6FW_SOCKET;
                case NETLINK_DNRTMSG:
                        return SECCLASS_NETLINK_DNRT_SOCKET;
                case NETLINK_KOBJECT_UEVENT:
                        return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
                default:
                        return SECCLASS_NETLINK_SOCKET;
                }
        case PF_PACKET:
                return SECCLASS_PACKET_SOCKET;
        case PF_KEY:
                return SECCLASS_KEY_SOCKET;
        case PF_APPLETALK:
                return SECCLASS_APPLETALK_SOCKET;
        }

        return SECCLASS_SOCKET;
}

#ifdef CONFIG_PROC_FS
static int selinux_proc_get_sid(struct dentry *dentry,
                                u16 tclass,
                                u32 *sid)
{
        int rc;
        char *buffer, *path;

        buffer = (char *)__get_free_page(GFP_KERNEL);
        if (!buffer)
                return -ENOMEM;

        path = dentry_path_raw(dentry, buffer, PAGE_SIZE);
        if (IS_ERR(path))
                rc = PTR_ERR(path);
        else {
                /* each process gets a /proc/PID/ entry. Strip off the
                 * PID part to get a valid selinux labeling.
                 * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
                while (path[1] >= '0' && path[1] <= '9') {
                        path[1] = '/';
                        path++;
                }
                rc = security_genfs_sid("proc", path, tclass, sid);
        }
        free_page((unsigned long)buffer);
        return rc;
}
#else
static int selinux_proc_get_sid(struct dentry *dentry,
                                u16 tclass,
                                u32 *sid)
{
        return -EINVAL;
}
#endif

/* The inode's security attributes must be initialized before first use. */
static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
{
        struct superblock_security_struct *sbsec = NULL;
        struct inode_security_struct *isec = inode->i_security;
        u32 sid;
        struct dentry *dentry;
#define INITCONTEXTLEN 255
        char *context = NULL;
        unsigned len = 0;
        int rc = 0;

        if (isec->initialized)
                goto out;

        mutex_lock(&isec->lock);
        if (isec->initialized)
                goto out_unlock;

        sbsec = inode->i_sb->s_security;
        if (!(sbsec->flags & SE_SBINITIALIZED)) {
                /* Defer initialization until selinux_complete_init,
                   after the initial policy is loaded and the security
                   server is ready to handle calls. */
                spin_lock(&sbsec->isec_lock);
                if (list_empty(&isec->list))
                        list_add(&isec->list, &sbsec->isec_head);
                spin_unlock(&sbsec->isec_lock);
                goto out_unlock;
        }

        switch (sbsec->behavior) {
        case SECURITY_FS_USE_NATIVE:
                break;
        case SECURITY_FS_USE_XATTR:
                if (!inode->i_op->getxattr) {
                        isec->sid = sbsec->def_sid;
                        break;
                }

                /* Need a dentry, since the xattr API requires one.
                   Life would be simpler if we could just pass the inode. */
                if (opt_dentry) {
                        /* Called from d_instantiate or d_splice_alias. */
                        dentry = dget(opt_dentry);
                } else {
                        /* Called from selinux_complete_init, try to find a dentry. */
                        dentry = d_find_alias(inode);
                }
                if (!dentry) {
                        /*
                         * this is can be hit on boot when a file is accessed
                         * before the policy is loaded.  When we load policy we
                         * may find inodes that have no dentry on the
                         * sbsec->isec_head list.  No reason to complain as these
                         * will get fixed up the next time we go through
                         * inode_doinit with a dentry, before these inodes could
                         * be used again by userspace.
                         */
                        goto out_unlock;
                }

                len = INITCONTEXTLEN;
                context = kmalloc(len+1, GFP_NOFS);
                if (!context) {
                        rc = -ENOMEM;
                        dput(dentry);
                        goto out_unlock;
                }
                context[len] = '\0';
                rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
                                           context, len);
                if (rc == -ERANGE) {
                        kfree(context);

                        /* Need a larger buffer.  Query for the right size. */
                        rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
                                                   NULL, 0);
                        if (rc < 0) {
                                dput(dentry);
                                goto out_unlock;
                        }
                        len = rc;
                        context = kmalloc(len+1, GFP_NOFS);
                        if (!context) {
                                rc = -ENOMEM;
                                dput(dentry);
                                goto out_unlock;
                        }
                        context[len] = '\0';
                        rc = inode->i_op->getxattr(dentry,
                                                   XATTR_NAME_SELINUX,
                                                   context, len);
                }
                dput(dentry);
                if (rc < 0) {
                        if (rc != -ENODATA) {
                                printk(KERN_WARNING "SELinux: %s:  getxattr returned "
                                       "%d for dev=%s ino=%ld\n", __func__,
                                       -rc, inode->i_sb->s_id, inode->i_ino);
                                kfree(context);
                                goto out_unlock;
                        }
                        /* Map ENODATA to the default file SID */
                        sid = sbsec->def_sid;
                        rc = 0;
                } else {
                        rc = security_context_to_sid_default(context, rc, &sid,
                                                             sbsec->def_sid,
                                                             GFP_NOFS);
                        if (rc) {
                                char *dev = inode->i_sb->s_id;
                                unsigned long ino = inode->i_ino;

                                if (rc == -EINVAL) {
                                        if (printk_ratelimit())
                                                printk(KERN_NOTICE "SELinux: inode=%lu on dev=%s was found to have an invalid "
                                                        "context=%s.  This indicates you may need to relabel the inode or the "
                                                        "filesystem in question.\n", ino, dev, context);
                                } else {
                                        printk(KERN_WARNING "SELinux: %s:  context_to_sid(%s) "
                                               "returned %d for dev=%s ino=%ld\n",
                                               __func__, context, -rc, dev, ino);
                                }
                                kfree(context);
                                /* Leave with the unlabeled SID */
                                rc = 0;
                                break;
                        }
                }
                kfree(context);
                isec->sid = sid;
                break;
        case SECURITY_FS_USE_TASK:
                isec->sid = isec->task_sid;
                break;
        case SECURITY_FS_USE_TRANS:
                /* Default to the fs SID. */
                isec->sid = sbsec->sid;

                /* Try to obtain a transition SID. */
                isec->sclass = inode_mode_to_security_class(inode->i_mode);
                rc = security_transition_sid(isec->task_sid, sbsec->sid,
                                             isec->sclass, NULL, &sid);
                if (rc)
                        goto out_unlock;
                isec->sid = sid;
                break;
        case SECURITY_FS_USE_MNTPOINT:
                isec->sid = sbsec->mntpoint_sid;
                break;
        default:
                /* Default to the fs superblock SID. */
                isec->sid = sbsec->sid;

                if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
                        /* We must have a dentry to determine the label on
                         * procfs inodes */
                        if (opt_dentry)
                                /* Called from d_instantiate or
                                 * d_splice_alias. */
                                dentry = dget(opt_dentry);
                        else
                                /* Called from selinux_complete_init, try to
                                 * find a dentry. */
                                dentry = d_find_alias(inode);
                        /*
                         * This can be hit on boot when a file is accessed
                         * before the policy is loaded.  When we load policy we
                         * may find inodes that have no dentry on the
                         * sbsec->isec_head list.  No reason to complain as
                         * these will get fixed up the next time we go through
                         * inode_doinit() with a dentry, before these inodes
                         * could be used again by userspace.
                         */
                        if (!dentry)
                                goto out_unlock;
                        isec->sclass = inode_mode_to_security_class(inode->i_mode);
                        rc = selinux_proc_get_sid(dentry, isec->sclass, &sid);
                        dput(dentry);
                        if (rc)
                                goto out_unlock;
                        isec->sid = sid;
                }
                break;
        }

        isec->initialized = 1;

out_unlock:
        mutex_unlock(&isec->lock);
out:
        if (isec->sclass == SECCLASS_FILE)
                isec->sclass = inode_mode_to_security_class(inode->i_mode);
        return rc;
}

/* Convert a Linux signal to an access vector. */
static inline u32 signal_to_av(int sig)
{
        u32 perm = 0;

        switch (sig) {
        case SIGCHLD:
                /* Commonly granted from child to parent. */
                perm = PROCESS__SIGCHLD;
                break;
        case SIGKILL:
                /* Cannot be caught or ignored */
                perm = PROCESS__SIGKILL;
                break;
        case SIGSTOP:
                /* Cannot be caught or ignored */
                perm = PROCESS__SIGSTOP;
                break;
        default:
                /* All other signals. */
                perm = PROCESS__SIGNAL;
                break;
        }

        return perm;
}

/*
 * Check permission between a pair of credentials
 * fork check, ptrace check, etc.
 */
static int cred_has_perm(const struct cred *actor,
                         const struct cred *target,
                         u32 perms)
{
        u32 asid = cred_sid(actor), tsid = cred_sid(target);

        return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL);
}

/*
 * Check permission between a pair of tasks, e.g. signal checks,
 * fork check, ptrace check, etc.
 * tsk1 is the actor and tsk2 is the target
 * - this uses the default subjective creds of tsk1
 */
static int task_has_perm(const struct task_struct *tsk1,
                         const struct task_struct *tsk2,
                         u32 perms)
{
        const struct task_security_struct *__tsec1, *__tsec2;
        u32 sid1, sid2;

        rcu_read_lock();
        __tsec1 = __task_cred(tsk1)->security;  sid1 = __tsec1->sid;
        __tsec2 = __task_cred(tsk2)->security;  sid2 = __tsec2->sid;
        rcu_read_unlock();
        return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL);
}

/*
 * Check permission between current and another task, e.g. signal checks,
 * fork check, ptrace check, etc.
 * current is the actor and tsk2 is the target
 * - this uses current's subjective creds
 */
static int current_has_perm(const struct task_struct *tsk,
                            u32 perms)
{
        u32 sid, tsid;

        sid = current_sid();
        tsid = task_sid(tsk);
        return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL);
}

#if CAP_LAST_CAP > 63
#error Fix SELinux to handle capabilities > 63.
#endif

/* Check whether a task is allowed to use a capability. */
static int cred_has_capability(const struct cred *cred,
                               int cap, int audit)
{
        struct common_audit_data ad;
        struct av_decision avd;
        u16 sclass;
        u32 sid = cred_sid(cred);
        u32 av = CAP_TO_MASK(cap);
        int rc;

        ad.type = LSM_AUDIT_DATA_CAP;
        ad.u.cap = cap;

        switch (CAP_TO_INDEX(cap)) {
        case 0:
                sclass = SECCLASS_CAPABILITY;
                break;
        case 1:
                sclass = SECCLASS_CAPABILITY2;
                break;
        default:
                printk(KERN_ERR
                       "SELinux:  out of range capability %d\n", cap);
                BUG();
                return -EINVAL;
        }

        rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
        if (audit == SECURITY_CAP_AUDIT) {
                int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
                if (rc2)
                        return rc2;
        }
        return rc;
}

/* Check whether a task is allowed to use a system operation. */
static int task_has_system(struct task_struct *tsk,
                           u32 perms)
{
        u32 sid = task_sid(tsk);

        return avc_has_perm(sid, SECINITSID_KERNEL,
                            SECCLASS_SYSTEM, perms, NULL);
}

/* Check whether a task has a particular permission to an inode.
   The 'adp' parameter is optional and allows other audit
   data to be passed (e.g. the dentry). */
static int inode_has_perm(const struct cred *cred,
                          struct inode *inode,
                          u32 perms,
                          struct common_audit_data *adp)
{
        struct inode_security_struct *isec;
        u32 sid;

        validate_creds(cred);

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        sid = cred_sid(cred);
        isec = inode->i_security;

        return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp);
}

/* Same as inode_has_perm, but pass explicit audit data containing
   the dentry to help the auditing code to more easily generate the
   pathname if needed. */
static inline int dentry_has_perm(const struct cred *cred,
                                  struct dentry *dentry,
                                  u32 av)
{
        struct inode *inode = d_backing_inode(dentry);
        struct common_audit_data ad;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = dentry;
        return inode_has_perm(cred, inode, av, &ad);
}

/* Same as inode_has_perm, but pass explicit audit data containing
   the path to help the auditing code to more easily generate the
   pathname if needed. */
static inline int path_has_perm(const struct cred *cred,
                                const struct path *path,
                                u32 av)
{
        struct inode *inode = d_backing_inode(path->dentry);
        struct common_audit_data ad;

        ad.type = LSM_AUDIT_DATA_PATH;
        ad.u.path = *path;
        return inode_has_perm(cred, inode, av, &ad);
}

/* Same as path_has_perm, but uses the inode from the file struct. */
static inline int file_path_has_perm(const struct cred *cred,
                                     struct file *file,
                                     u32 av)
{
        struct common_audit_data ad;

        ad.type = LSM_AUDIT_DATA_PATH;
        ad.u.path = file->f_path;
        return inode_has_perm(cred, file_inode(file), av, &ad);
}

/* Check whether a task can use an open file descriptor to
   access an inode in a given way.  Check access to the
   descriptor itself, and then use dentry_has_perm to
   check a particular permission to the file.
   Access to the descriptor is implicitly granted if it
   has the same SID as the process.  If av is zero, then
   access to the file is not checked, e.g. for cases
   where only the descriptor is affected like seek. */
static int file_has_perm(const struct cred *cred,
                         struct file *file,
                         u32 av)
{
        struct file_security_struct *fsec = file->f_security;
        struct inode *inode = file_inode(file);
        struct common_audit_data ad;
        u32 sid = cred_sid(cred);
        int rc;

        ad.type = LSM_AUDIT_DATA_PATH;
        ad.u.path = file->f_path;

        if (sid != fsec->sid) {
                rc = avc_has_perm(sid, fsec->sid,
                                  SECCLASS_FD,
                                  FD__USE,
                                  &ad);
                if (rc)
                        goto out;
        }

        /* av is zero if only checking access to the descriptor. */
        rc = 0;
        if (av)
                rc = inode_has_perm(cred, inode, av, &ad);

out:
        return rc;
}

/* Check whether a task can create a file. */
static int may_create(struct inode *dir,
                      struct dentry *dentry,
                      u16 tclass)
{
        const struct task_security_struct *tsec = current_security();
        struct inode_security_struct *dsec;
        struct superblock_security_struct *sbsec;
        u32 sid, newsid;
        struct common_audit_data ad;
        int rc;

        dsec = dir->i_security;
        sbsec = dir->i_sb->s_security;

        sid = tsec->sid;
        newsid = tsec->create_sid;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = dentry;

        rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
                          DIR__ADD_NAME | DIR__SEARCH,
                          &ad);
        if (rc)
                return rc;

        if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
                rc = security_transition_sid(sid, dsec->sid, tclass,
                                             &dentry->d_name, &newsid);
                if (rc)
                        return rc;
        }

        rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
        if (rc)
                return rc;

        return avc_has_perm(newsid, sbsec->sid,
                            SECCLASS_FILESYSTEM,
                            FILESYSTEM__ASSOCIATE, &ad);
}

/* Check whether a task can create a key. */
static int may_create_key(u32 ksid,
                          struct task_struct *ctx)
{
        u32 sid = task_sid(ctx);

        return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL);
}

#define MAY_LINK        0
#define MAY_UNLINK      1
#define MAY_RMDIR       2

/* Check whether a task can link, unlink, or rmdir a file/directory. */
static int may_link(struct inode *dir,
                    struct dentry *dentry,
                    int kind)

{
        struct inode_security_struct *dsec, *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        u32 av;
        int rc;

        dsec = dir->i_security;
        isec = d_backing_inode(dentry)->i_security;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = dentry;

        av = DIR__SEARCH;
        av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
        rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad);
        if (rc)
                return rc;

        switch (kind) {
        case MAY_LINK:
                av = FILE__LINK;
                break;
        case MAY_UNLINK:
                av = FILE__UNLINK;
                break;
        case MAY_RMDIR:
                av = DIR__RMDIR;
                break;
        default:
                printk(KERN_WARNING "SELinux: %s:  unrecognized kind %d\n",
                        __func__, kind);
                return 0;
        }

        rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad);
        return rc;
}

static inline int may_rename(struct inode *old_dir,
                             struct dentry *old_dentry,
                             struct inode *new_dir,
                             struct dentry *new_dentry)
{
        struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        u32 av;
        int old_is_dir, new_is_dir;
        int rc;

        old_dsec = old_dir->i_security;
        old_isec = d_backing_inode(old_dentry)->i_security;
        old_is_dir = d_is_dir(old_dentry);
        new_dsec = new_dir->i_security;

        ad.type = LSM_AUDIT_DATA_DENTRY;

        ad.u.dentry = old_dentry;
        rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
                          DIR__REMOVE_NAME | DIR__SEARCH, &ad);
        if (rc)
                return rc;
        rc = avc_has_perm(sid, old_isec->sid,
                          old_isec->sclass, FILE__RENAME, &ad);
        if (rc)
                return rc;
        if (old_is_dir && new_dir != old_dir) {
                rc = avc_has_perm(sid, old_isec->sid,
                                  old_isec->sclass, DIR__REPARENT, &ad);
                if (rc)
                        return rc;
        }

        ad.u.dentry = new_dentry;
        av = DIR__ADD_NAME | DIR__SEARCH;
        if (d_is_positive(new_dentry))
                av |= DIR__REMOVE_NAME;
        rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
        if (rc)
                return rc;
        if (d_is_positive(new_dentry)) {
                new_isec = d_backing_inode(new_dentry)->i_security;
                new_is_dir = d_is_dir(new_dentry);
                rc = avc_has_perm(sid, new_isec->sid,
                                  new_isec->sclass,
                                  (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
                if (rc)
                        return rc;
        }

        return 0;
}

/* Check whether a task can perform a filesystem operation. */
static int superblock_has_perm(const struct cred *cred,
                               struct super_block *sb,
                               u32 perms,
                               struct common_audit_data *ad)
{
        struct superblock_security_struct *sbsec;
        u32 sid = cred_sid(cred);

        sbsec = sb->s_security;
        return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
}

/* Convert a Linux mode and permission mask to an access vector. */
static inline u32 file_mask_to_av(int mode, int mask)
{
        u32 av = 0;

        if (!S_ISDIR(mode)) {
                if (mask & MAY_EXEC)
                        av |= FILE__EXECUTE;
                if (mask & MAY_READ)
                        av |= FILE__READ;

                if (mask & MAY_APPEND)
                        av |= FILE__APPEND;
                else if (mask & MAY_WRITE)
                        av |= FILE__WRITE;

        } else {
                if (mask & MAY_EXEC)
                        av |= DIR__SEARCH;
                if (mask & MAY_WRITE)
                        av |= DIR__WRITE;
                if (mask & MAY_READ)
                        av |= DIR__READ;
        }

        return av;
}

/* Convert a Linux file to an access vector. */
static inline u32 file_to_av(struct file *file)
{
        u32 av = 0;

        if (file->f_mode & FMODE_READ)
                av |= FILE__READ;
        if (file->f_mode & FMODE_WRITE) {
                if (file->f_flags & O_APPEND)
                        av |= FILE__APPEND;
                else
                        av |= FILE__WRITE;
        }
        if (!av) {
                /*
                 * Special file opened with flags 3 for ioctl-only use.
                 */
                av = FILE__IOCTL;
        }

        return av;
}

/*
 * Convert a file to an access vector and include the correct open
 * open permission.
 */
static inline u32 open_file_to_av(struct file *file)
{
        u32 av = file_to_av(file);

        if (selinux_policycap_openperm)
                av |= FILE__OPEN;

        return av;
}

/* Hook functions begin here. */

static int selinux_binder_set_context_mgr(struct task_struct *mgr)
{
        u32 mysid = current_sid();
        u32 mgrsid = task_sid(mgr);

        return avc_has_perm(mysid, mgrsid, SECCLASS_BINDER,
                            BINDER__SET_CONTEXT_MGR, NULL);
}

static int selinux_binder_transaction(struct task_struct *from,
                                      struct task_struct *to)
{
        u32 mysid = current_sid();
        u32 fromsid = task_sid(from);
        u32 tosid = task_sid(to);
        int rc;

        if (mysid != fromsid) {
                rc = avc_has_perm(mysid, fromsid, SECCLASS_BINDER,
                                  BINDER__IMPERSONATE, NULL);
                if (rc)
                        return rc;
        }

        return avc_has_perm(fromsid, tosid, SECCLASS_BINDER, BINDER__CALL,
                            NULL);
}

static int selinux_binder_transfer_binder(struct task_struct *from,
                                          struct task_struct *to)
{
        u32 fromsid = task_sid(from);
        u32 tosid = task_sid(to);

        return avc_has_perm(fromsid, tosid, SECCLASS_BINDER, BINDER__TRANSFER,
                            NULL);
}

static int selinux_binder_transfer_file(struct task_struct *from,
                                        struct task_struct *to,
                                        struct file *file)
{
        u32 sid = task_sid(to);
        struct file_security_struct *fsec = file->f_security;
        struct inode *inode = d_backing_inode(file->f_path.dentry);
        struct inode_security_struct *isec = inode->i_security;
        struct common_audit_data ad;
        int rc;

        ad.type = LSM_AUDIT_DATA_PATH;
        ad.u.path = file->f_path;

        if (sid != fsec->sid) {
                rc = avc_has_perm(sid, fsec->sid,
                                  SECCLASS_FD,
                                  FD__USE,
                                  &ad);
                if (rc)
                        return rc;
        }

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        return avc_has_perm(sid, isec->sid, isec->sclass, file_to_av(file),
                            &ad);
}

static int selinux_ptrace_access_check(struct task_struct *child,
                                     unsigned int mode)
{
        int rc;

        rc = cap_ptrace_access_check(child, mode);
        if (rc)
                return rc;

        if (mode & PTRACE_MODE_READ) {
                u32 sid = current_sid();
                u32 csid = task_sid(child);
                return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL);
        }

        return current_has_perm(child, PROCESS__PTRACE);
}

static int selinux_ptrace_traceme(struct task_struct *parent)
{
        int rc;

        rc = cap_ptrace_traceme(parent);
        if (rc)
                return rc;

        return task_has_perm(parent, current, PROCESS__PTRACE);
}

static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
                          kernel_cap_t *inheritable, kernel_cap_t *permitted)
{
        int error;

        error = current_has_perm(target, PROCESS__GETCAP);
        if (error)
                return error;

        return cap_capget(target, effective, inheritable, permitted);
}

static int selinux_capset(struct cred *new, const struct cred *old,
                          const kernel_cap_t *effective,
                          const kernel_cap_t *inheritable,
                          const kernel_cap_t *permitted)
{
        int error;

        error = cap_capset(new, old,
                                      effective, inheritable, permitted);
        if (error)
                return error;

        return cred_has_perm(old, new, PROCESS__SETCAP);
}

/*
 * (This comment used to live with the selinux_task_setuid hook,
 * which was removed).
 *
 * Since setuid only affects the current process, and since the SELinux
 * controls are not based on the Linux identity attributes, SELinux does not
 * need to control this operation.  However, SELinux does control the use of
 * the CAP_SETUID and CAP_SETGID capabilities using the capable hook.
 */

static int selinux_capable(const struct cred *cred, struct user_namespace *ns,
                           int cap, int audit)
{
        int rc;

        rc = cap_capable(cred, ns, cap, audit);
        if (rc)
                return rc;

        return cred_has_capability(cred, cap, audit);
}

static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
{
        const struct cred *cred = current_cred();
        int rc = 0;

        if (!sb)
                return 0;

        switch (cmds) {
        case Q_SYNC:
        case Q_QUOTAON:
        case Q_QUOTAOFF:
        case Q_SETINFO:
        case Q_SETQUOTA:
                rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
                break;
        case Q_GETFMT:
        case Q_GETINFO:
        case Q_GETQUOTA:
                rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
                break;
        default:
                rc = 0;  /* let the kernel handle invalid cmds */
                break;
        }
        return rc;
}

static int selinux_quota_on(struct dentry *dentry)
{
        const struct cred *cred = current_cred();

        return dentry_has_perm(cred, dentry, FILE__QUOTAON);
}

static int selinux_syslog(int type)
{
        int rc;

        switch (type) {
        case SYSLOG_ACTION_READ_ALL:    /* Read last kernel messages */
        case SYSLOG_ACTION_SIZE_BUFFER: /* Return size of the log buffer */
                rc = task_has_system(current, SYSTEM__SYSLOG_READ);
                break;
        case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
        case SYSLOG_ACTION_CONSOLE_ON:  /* Enable logging to console */
        /* Set level of messages printed to console */
        case SYSLOG_ACTION_CONSOLE_LEVEL:
                rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE);
                break;
        case SYSLOG_ACTION_CLOSE:       /* Close log */
        case SYSLOG_ACTION_OPEN:        /* Open log */
        case SYSLOG_ACTION_READ:        /* Read from log */
        case SYSLOG_ACTION_READ_CLEAR:  /* Read/clear last kernel messages */
        case SYSLOG_ACTION_CLEAR:       /* Clear ring buffer */
        default:
                rc = task_has_system(current, SYSTEM__SYSLOG_MOD);
                break;
        }
        return rc;
}

/*
 * Check that a process has enough memory to allocate a new virtual
 * mapping. 0 means there is enough memory for the allocation to
 * succeed and -ENOMEM implies there is not.
 *
 * Do not audit the selinux permission check, as this is applied to all
 * processes that allocate mappings.
 */
static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
{
        int rc, cap_sys_admin = 0;

        rc = selinux_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN,
                             SECURITY_CAP_NOAUDIT);
        if (rc == 0)
                cap_sys_admin = 1;

        return __vm_enough_memory(mm, pages, cap_sys_admin);
}

/* binprm security operations */

static int check_nnp_nosuid(const struct linux_binprm *bprm,
                            const struct task_security_struct *old_tsec,
                            const struct task_security_struct *new_tsec)
{
        int nnp = (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS);
        int nosuid = (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID);
        int rc;

        if (!nnp && !nosuid)
                return 0; /* neither NNP nor nosuid */

        if (new_tsec->sid == old_tsec->sid)
                return 0; /* No change in credentials */

        /*
         * The only transitions we permit under NNP or nosuid
         * are transitions to bounded SIDs, i.e. SIDs that are
         * guaranteed to only be allowed a subset of the permissions
         * of the current SID.
         */
        rc = security_bounded_transition(old_tsec->sid, new_tsec->sid);
        if (rc) {
                /*
                 * On failure, preserve the errno values for NNP vs nosuid.
                 * NNP:  Operation not permitted for caller.
                 * nosuid:  Permission denied to file.
                 */
                if (nnp)
                        return -EPERM;
                else
                        return -EACCES;
        }
        return 0;
}

static int selinux_bprm_set_creds(struct linux_binprm *bprm)
{
        const struct task_security_struct *old_tsec;
        struct task_security_struct *new_tsec;
        struct inode_security_struct *isec;
        struct common_audit_data ad;
        struct inode *inode = file_inode(bprm->file);
        int rc;

        rc = cap_bprm_set_creds(bprm);
        if (rc)
                return rc;

        /* SELinux context only depends on initial program or script and not
         * the script interpreter */
        if (bprm->cred_prepared)
                return 0;

        old_tsec = current_security();
        new_tsec = bprm->cred->security;
        isec = inode->i_security;

        /* Default to the current task SID. */
        new_tsec->sid = old_tsec->sid;
        new_tsec->osid = old_tsec->sid;

        /* Reset fs, key, and sock SIDs on execve. */
        new_tsec->create_sid = 0;
        new_tsec->keycreate_sid = 0;
        new_tsec->sockcreate_sid = 0;

        if (old_tsec->exec_sid) {
                new_tsec->sid = old_tsec->exec_sid;
                /* Reset exec SID on execve. */
                new_tsec->exec_sid = 0;

                /* Fail on NNP or nosuid if not an allowed transition. */
                rc = check_nnp_nosuid(bprm, old_tsec, new_tsec);
                if (rc)
                        return rc;
        } else {
                /* Check for a default transition on this program. */
                rc = security_transition_sid(old_tsec->sid, isec->sid,
                                             SECCLASS_PROCESS, NULL,
                                             &new_tsec->sid);
                if (rc)
                        return rc;

                /*
                 * Fallback to old SID on NNP or nosuid if not an allowed
                 * transition.
                 */
                rc = check_nnp_nosuid(bprm, old_tsec, new_tsec);
                if (rc)
                        new_tsec->sid = old_tsec->sid;
        }

        ad.type = LSM_AUDIT_DATA_PATH;
        ad.u.path = bprm->file->f_path;

        if (new_tsec->sid == old_tsec->sid) {
                rc = avc_has_perm(old_tsec->sid, isec->sid,
                                  SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
                if (rc)
                        return rc;
        } else {
                /* Check permissions for the transition. */
                rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
                                  SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
                if (rc)
                        return rc;

                rc = avc_has_perm(new_tsec->sid, isec->sid,
                                  SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
                if (rc)
                        return rc;

                /* Check for shared state */
                if (bprm->unsafe & LSM_UNSAFE_SHARE) {
                        rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
                                          SECCLASS_PROCESS, PROCESS__SHARE,
                                          NULL);
                        if (rc)
                                return -EPERM;
                }

                /* Make sure that anyone attempting to ptrace over a task that
                 * changes its SID has the appropriate permit */
                if (bprm->unsafe &
                    (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
                        struct task_struct *tracer;
                        struct task_security_struct *sec;
                        u32 ptsid = 0;

                        rcu_read_lock();
                        tracer = ptrace_parent(current);
                        if (likely(tracer != NULL)) {
                                sec = __task_cred(tracer)->security;
                                ptsid = sec->sid;
                        }
                        rcu_read_unlock();

                        if (ptsid != 0) {
                                rc = avc_has_perm(ptsid, new_tsec->sid,
                                                  SECCLASS_PROCESS,
                                                  PROCESS__PTRACE, NULL);
                                if (rc)
                                        return -EPERM;
                        }
                }

                /* Clear any possibly unsafe personality bits on exec: */
                bprm->per_clear |= PER_CLEAR_ON_SETID;
        }

        return 0;
}

static int selinux_bprm_secureexec(struct linux_binprm *bprm)
{
        const struct task_security_struct *tsec = current_security();
        u32 sid, osid;
        int atsecure = 0;

        sid = tsec->sid;
        osid = tsec->osid;

        if (osid != sid) {
                /* Enable secure mode for SIDs transitions unless
                   the noatsecure permission is granted between
                   the two SIDs, i.e. ahp returns 0. */
                atsecure = avc_has_perm(osid, sid,
                                        SECCLASS_PROCESS,
                                        PROCESS__NOATSECURE, NULL);
        }

        return (atsecure || cap_bprm_secureexec(bprm));
}

static int match_file(const void *p, struct file *file, unsigned fd)
{
        return file_has_perm(p, file, file_to_av(file)) ? fd + 1 : 0;
}

/* Derived from fs/exec.c:flush_old_files. */
static inline void flush_unauthorized_files(const struct cred *cred,
                                            struct files_struct *files)
{
        struct file *file, *devnull = NULL;
        struct tty_struct *tty;
        int drop_tty = 0;
        unsigned n;

        tty = get_current_tty();
        if (tty) {
                spin_lock(&tty_files_lock);
                if (!list_empty(&tty->tty_files)) {
                        struct tty_file_private *file_priv;

                        /* Revalidate access to controlling tty.
                           Use file_path_has_perm on the tty path directly
                           rather than using file_has_perm, as this particular
                           open file may belong to another process and we are
                           only interested in the inode-based check here. */
                        file_priv = list_first_entry(&tty->tty_files,
                                                struct tty_file_private, list);
                        file = file_priv->file;
                        if (file_path_has_perm(cred, file, FILE__READ | FILE__WRITE))
                                drop_tty = 1;
                }
                spin_unlock(&tty_files_lock);
                tty_kref_put(tty);
        }
        /* Reset controlling tty. */
        if (drop_tty)
                no_tty();

        /* Revalidate access to inherited open files. */
        n = iterate_fd(files, 0, match_file, cred);
        if (!n) /* none found? */
                return;

        devnull = dentry_open(&selinux_null, O_RDWR, cred);
        if (IS_ERR(devnull))
                devnull = NULL;
        /* replace all the matching ones with this */
        do {
                replace_fd(n - 1, devnull, 0);
        } while ((n = iterate_fd(files, n, match_file, cred)) != 0);
        if (devnull)
                fput(devnull);
}

/*
 * Prepare a process for imminent new credential changes due to exec
 */
static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
{
        struct task_security_struct *new_tsec;
        struct rlimit *rlim, *initrlim;
        int rc, i;

        new_tsec = bprm->cred->security;
        if (new_tsec->sid == new_tsec->osid)
                return;

        /* Close files for which the new task SID is not authorized. */
        flush_unauthorized_files(bprm->cred, current->files);

        /* Always clear parent death signal on SID transitions. */
        current->pdeath_signal = 0;

        /* Check whether the new SID can inherit resource limits from the old
         * SID.  If not, reset all soft limits to the lower of the current
         * task's hard limit and the init task's soft limit.
         *
         * Note that the setting of hard limits (even to lower them) can be
         * controlled by the setrlimit check.  The inclusion of the init task's
         * soft limit into the computation is to avoid resetting soft limits
         * higher than the default soft limit for cases where the default is
         * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
         */
        rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
                          PROCESS__RLIMITINH, NULL);
        if (rc) {
                /* protect against do_prlimit() */
                task_lock(current);
                for (i = 0; i < RLIM_NLIMITS; i++) {
                        rlim = current->signal->rlim + i;
                        initrlim = init_task.signal->rlim + i;
                        rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
                }
                task_unlock(current);
                update_rlimit_cpu(current, rlimit(RLIMIT_CPU));
        }
}

/*
 * Clean up the process immediately after the installation of new credentials
 * due to exec
 */
static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
{
        const struct task_security_struct *tsec = current_security();
        struct itimerval itimer;
        u32 osid, sid;
        int rc, i;

        osid = tsec->osid;
        sid = tsec->sid;

        if (sid == osid)
                return;

        /* Check whether the new SID can inherit signal state from the old SID.
         * If not, clear itimers to avoid subsequent signal generation and
         * flush and unblock signals.
         *
         * This must occur _after_ the task SID has been updated so that any
         * kill done after the flush will be checked against the new SID.
         */
        rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
        if (rc) {
                memset(&itimer, 0, sizeof itimer);
                for (i = 0; i < 3; i++)
                        do_setitimer(i, &itimer, NULL);
                spin_lock_irq(&current->sighand->siglock);
                if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
                        __flush_signals(current);
                        flush_signal_handlers(current, 1);
                        sigemptyset(&current->blocked);
                }
                spin_unlock_irq(&current->sighand->siglock);
        }

        /* Wake up the parent if it is waiting so that it can recheck
         * wait permission to the new task SID. */
        read_lock(&tasklist_lock);
        __wake_up_parent(current, current->real_parent);
        read_unlock(&tasklist_lock);
}

/* superblock security operations */

static int selinux_sb_alloc_security(struct super_block *sb)
{
        return superblock_alloc_security(sb);
}

static void selinux_sb_free_security(struct super_block *sb)
{
        superblock_free_security(sb);
}

static inline int match_prefix(char *prefix, int plen, char *option, int olen)
{
        if (plen > olen)
                return 0;

        return !memcmp(prefix, option, plen);
}

static inline int selinux_option(char *option, int len)
{
        return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
                match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
                match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
                match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
                match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
}

static inline void take_option(char **to, char *from, int *first, int len)
{
        if (!*first) {
                **to = ',';
                *to += 1;
        } else
                *first = 0;
        memcpy(*to, from, len);
        *to += len;
}

static inline void take_selinux_option(char **to, char *from, int *first,
                                       int len)
{
        int current_size = 0;

        if (!*first) {
                **to = '|';
                *to += 1;
        } else
                *first = 0;

        while (current_size < len) {
                if (*from != '"') {
                        **to = *from;
                        *to += 1;
                }
                from += 1;
                current_size += 1;
        }
}

static int selinux_sb_copy_data(char *orig, char *copy)
{
        int fnosec, fsec, rc = 0;
        char *in_save, *in_curr, *in_end;
        char *sec_curr, *nosec_save, *nosec;
        int open_quote = 0;

        in_curr = orig;
        sec_curr = copy;

        nosec = (char *)get_zeroed_page(GFP_KERNEL);
        if (!nosec) {
                rc = -ENOMEM;
                goto out;
        }

        nosec_save = nosec;
        fnosec = fsec = 1;
        in_save = in_end = orig;

        do {
                if (*in_end == '"')
                        open_quote = !open_quote;
                if ((*in_end == ',' && open_quote == 0) ||
                                *in_end == '\0') {
                        int len = in_end - in_curr;

                        if (selinux_option(in_curr, len))
                                take_selinux_option(&sec_curr, in_curr, &fsec, len);
                        else
                                take_option(&nosec, in_curr, &fnosec, len);

                        in_curr = in_end + 1;
                }
        } while (*in_end++);

        strcpy(in_save, nosec_save);
        free_page((unsigned long)nosec_save);
out:
        return rc;
}

static int selinux_sb_remount(struct super_block *sb, void *data)
{
        int rc, i, *flags;
        struct security_mnt_opts opts;
        char *secdata, **mount_options;
        struct superblock_security_struct *sbsec = sb->s_security;

        if (!(sbsec->flags & SE_SBINITIALIZED))
                return 0;

        if (!data)
                return 0;

        if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
                return 0;

        security_init_mnt_opts(&opts);
        secdata = alloc_secdata();
        if (!secdata)
                return -ENOMEM;
        rc = selinux_sb_copy_data(data, secdata);
        if (rc)
                goto out_free_secdata;

        rc = selinux_parse_opts_str(secdata, &opts);
        if (rc)
                goto out_free_secdata;

        mount_options = opts.mnt_opts;
        flags = opts.mnt_opts_flags;

        for (i = 0; i < opts.num_mnt_opts; i++) {
                u32 sid;
                size_t len;

                if (flags[i] == SBLABEL_MNT)
                        continue;
                len = strlen(mount_options[i]);
                rc = security_context_to_sid(mount_options[i], len, &sid,
                                             GFP_KERNEL);
                if (rc) {
                        printk(KERN_WARNING "SELinux: security_context_to_sid"
                               "(%s) failed for (dev %s, type %s) errno=%d\n",
                               mount_options[i], sb->s_id, sb->s_type->name, rc);
                        goto out_free_opts;
                }
                rc = -EINVAL;
                switch (flags[i]) {
                case FSCONTEXT_MNT:
                        if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
                                goto out_bad_option;
                        break;
                case CONTEXT_MNT:
                        if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
                                goto out_bad_option;
                        break;
                case ROOTCONTEXT_MNT: {
                        struct inode_security_struct *root_isec;
                        root_isec = d_backing_inode(sb->s_root)->i_security;

                        if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
                                goto out_bad_option;
                        break;
                }
                case DEFCONTEXT_MNT:
                        if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
                                goto out_bad_option;
                        break;
                default:
                        goto out_free_opts;
                }
        }

        rc = 0;
out_free_opts:
        security_free_mnt_opts(&opts);
out_free_secdata:
        free_secdata(secdata);
        return rc;
out_bad_option:
        printk(KERN_WARNING "SELinux: unable to change security options "
               "during remount (dev %s, type=%s)\n", sb->s_id,
               sb->s_type->name);
        goto out_free_opts;
}

static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
{
        const struct cred *cred = current_cred();
        struct common_audit_data ad;
        int rc;

        rc = superblock_doinit(sb, data);
        if (rc)
                return rc;

        /* Allow all mounts performed by the kernel */
        if (flags & MS_KERNMOUNT)
                return 0;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = sb->s_root;
        return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
}

static int selinux_sb_statfs(struct dentry *dentry)
{
        const struct cred *cred = current_cred();
        struct common_audit_data ad;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = dentry->d_sb->s_root;
        return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
}

static int selinux_mount(const char *dev_name,
                         struct path *path,
                         const char *type,
                         unsigned long flags,
                         void *data)
{
        const struct cred *cred = current_cred();

        if (flags & MS_REMOUNT)
                return superblock_has_perm(cred, path->dentry->d_sb,
                                           FILESYSTEM__REMOUNT, NULL);
        else
                return path_has_perm(cred, path, FILE__MOUNTON);
}

static int selinux_umount(struct vfsmount *mnt, int flags)
{
        const struct cred *cred = current_cred();

        return superblock_has_perm(cred, mnt->mnt_sb,
                                   FILESYSTEM__UNMOUNT, NULL);
}

/* inode security operations */

static int selinux_inode_alloc_security(struct inode *inode)
{
        return inode_alloc_security(inode);
}

static void selinux_inode_free_security(struct inode *inode)
{
        inode_free_security(inode);
}

static int selinux_dentry_init_security(struct dentry *dentry, int mode,
                                        struct qstr *name, void **ctx,
                                        u32 *ctxlen)
{
        const struct cred *cred = current_cred();
        struct task_security_struct *tsec;
        struct inode_security_struct *dsec;
        struct superblock_security_struct *sbsec;
        struct inode *dir = d_backing_inode(dentry->d_parent);
        u32 newsid;
        int rc;

        tsec = cred->security;
        dsec = dir->i_security;
        sbsec = dir->i_sb->s_security;

        if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) {
                newsid = tsec->create_sid;
        } else {
                rc = security_transition_sid(tsec->sid, dsec->sid,
                                             inode_mode_to_security_class(mode),
                                             name,
                                             &newsid);
                if (rc) {
                        printk(KERN_WARNING
                                "%s: security_transition_sid failed, rc=%d\n",
                               __func__, -rc);
                        return rc;
                }
        }

        return security_sid_to_context(newsid, (char **)ctx, ctxlen);
}

static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
                                       const struct qstr *qstr,
                                       const char **name,
                                       void **value, size_t *len)
{
        const struct task_security_struct *tsec = current_security();
        struct inode_security_struct *dsec;
        struct superblock_security_struct *sbsec;
        u32 sid, newsid, clen;
        int rc;
        char *context;

        dsec = dir->i_security;
        sbsec = dir->i_sb->s_security;

        sid = tsec->sid;
        newsid = tsec->create_sid;

        if ((sbsec->flags & SE_SBINITIALIZED) &&
            (sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
                newsid = sbsec->mntpoint_sid;
        else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
                rc = security_transition_sid(sid, dsec->sid,
                                             inode_mode_to_security_class(inode->i_mode),
                                             qstr, &newsid);
                if (rc) {
                        printk(KERN_WARNING "%s:  "
                               "security_transition_sid failed, rc=%d (dev=%s "
                               "ino=%ld)\n",
                               __func__,
                               -rc, inode->i_sb->s_id, inode->i_ino);
                        return rc;
                }
        }

        /* Possibly defer initialization to selinux_complete_init. */
        if (sbsec->flags & SE_SBINITIALIZED) {
                struct inode_security_struct *isec = inode->i_security;
                isec->sclass = inode_mode_to_security_class(inode->i_mode);
                isec->sid = newsid;
                isec->initialized = 1;
        }

        if (!ss_initialized || !(sbsec->flags & SBLABEL_MNT))
                return -EOPNOTSUPP;

        if (name)
                *name = XATTR_SELINUX_SUFFIX;

        if (value && len) {
                rc = security_sid_to_context_force(newsid, &context, &clen);
                if (rc)
                        return rc;
                *value = context;
                *len = clen;
        }

        return 0;
}

static int selinux_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode)
{
        return may_create(dir, dentry, SECCLASS_FILE);
}

static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
{
        return may_link(dir, old_dentry, MAY_LINK);
}

static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
{
        return may_link(dir, dentry, MAY_UNLINK);
}

static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
{
        return may_create(dir, dentry, SECCLASS_LNK_FILE);
}

static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, umode_t mask)
{
        return may_create(dir, dentry, SECCLASS_DIR);
}

static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
        return may_link(dir, dentry, MAY_RMDIR);
}

static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
{
        return may_create(dir, dentry, inode_mode_to_security_class(mode));
}

static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
                                struct inode *new_inode, struct dentry *new_dentry)
{
        return may_rename(old_inode, old_dentry, new_inode, new_dentry);
}

static int selinux_inode_readlink(struct dentry *dentry)
{
        const struct cred *cred = current_cred();

        return dentry_has_perm(cred, dentry, FILE__READ);
}

static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata)
{
        const struct cred *cred = current_cred();

        return dentry_has_perm(cred, dentry, FILE__READ);
}

static noinline int audit_inode_permission(struct inode *inode,
                                           u32 perms, u32 audited, u32 denied,
                                           int result,
                                           unsigned flags)
{
        struct common_audit_data ad;
        struct inode_security_struct *isec = inode->i_security;
        int rc;

        ad.type = LSM_AUDIT_DATA_INODE;
        ad.u.inode = inode;

        rc = slow_avc_audit(current_sid(), isec->sid, isec->sclass, perms,
                            audited, denied, result, &ad, flags);
        if (rc)
                return rc;
        return 0;
}

static int selinux_inode_permission(struct inode *inode, int mask)
{
        const struct cred *cred = current_cred();
        u32 perms;
        bool from_access;
        unsigned flags = mask & MAY_NOT_BLOCK;
        struct inode_security_struct *isec;
        u32 sid;
        struct av_decision avd;
        int rc, rc2;
        u32 audited, denied;

        from_access = mask & MAY_ACCESS;
        mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);

        /* No permission to check.  Existence test. */
        if (!mask)
                return 0;

        validate_creds(cred);

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        perms = file_mask_to_av(inode->i_mode, mask);

        sid = cred_sid(cred);
        isec = inode->i_security;

        rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd);
        audited = avc_audit_required(perms, &avd, rc,
                                     from_access ? FILE__AUDIT_ACCESS : 0,
                                     &denied);
        if (likely(!audited))
                return rc;

        rc2 = audit_inode_permission(inode, perms, audited, denied, rc, flags);
        if (rc2)
                return rc2;
        return rc;
}

static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
        const struct cred *cred = current_cred();
        unsigned int ia_valid = iattr->ia_valid;
        __u32 av = FILE__WRITE;

        /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
        if (ia_valid & ATTR_FORCE) {
                ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE |
                              ATTR_FORCE);
                if (!ia_valid)
                        return 0;
        }

        if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
                        ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET))
                return dentry_has_perm(cred, dentry, FILE__SETATTR);

        if (selinux_policycap_openperm && (ia_valid & ATTR_SIZE))
                av |= FILE__OPEN;

        return dentry_has_perm(cred, dentry, av);
}

static int selinux_inode_getattr(const struct path *path)
{
        return path_has_perm(current_cred(), path, FILE__GETATTR);
}

static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name)
{
        const struct cred *cred = current_cred();

        if (!strncmp(name, XATTR_SECURITY_PREFIX,
                     sizeof XATTR_SECURITY_PREFIX - 1)) {
                if (!strcmp(name, XATTR_NAME_CAPS)) {
                        if (!capable(CAP_SETFCAP))
                                return -EPERM;
                } else if (!capable(CAP_SYS_ADMIN)) {
                        /* A different attribute in the security namespace.
                           Restrict to administrator. */
                        return -EPERM;
                }
        }

        /* Not an attribute we recognize, so just check the
           ordinary setattr permission. */
        return dentry_has_perm(cred, dentry, FILE__SETATTR);
}

static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
                                  const void *value, size_t size, int flags)
{
        struct inode *inode = d_backing_inode(dentry);
        struct inode_security_struct *isec = inode->i_security;
        struct superblock_security_struct *sbsec;
        struct common_audit_data ad;
        u32 newsid, sid = current_sid();
        int rc = 0;

        if (strcmp(name, XATTR_NAME_SELINUX))
                return selinux_inode_setotherxattr(dentry, name);

        sbsec = inode->i_sb->s_security;
        if (!(sbsec->flags & SBLABEL_MNT))
                return -EOPNOTSUPP;

        if (!inode_owner_or_capable(inode))
                return -EPERM;

        ad.type = LSM_AUDIT_DATA_DENTRY;
        ad.u.dentry = dentry;

        rc = avc_has_perm(sid, isec->sid, isec->sclass,
                          FILE__RELABELFROM, &ad);
        if (rc)
                return rc;

        rc = security_context_to_sid(value, size, &newsid, GFP_KERNEL);
        if (rc == -EINVAL) {
                if (!capable(CAP_MAC_ADMIN)) {
                        struct audit_buffer *ab;
                        size_t audit_size;
                        const char *str;

                        /* We strip a nul only if it is at the end, otherwise the
                         * context contains a nul and we should audit that */
                        if (value) {
                                str = value;
                                if (str[size - 1] == '\0')
                                        audit_size = size - 1;
                                else
                                        audit_size = size;
                        } else {
                                str = "";
                                audit_size = 0;
                        }
                        ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
                        audit_log_format(ab, "op=setxattr invalid_context=");
                        audit_log_n_untrustedstring(ab, value, audit_size);
                        audit_log_end(ab);

                        return rc;
                }
                rc = security_context_to_sid_force(value, size, &newsid);
        }
        if (rc)
                return rc;

        rc = avc_has_perm(sid, newsid, isec->sclass,
                          FILE__RELABELTO, &ad);
        if (rc)
                return rc;

        rc = security_validate_transition(isec->sid, newsid, sid,
                                          isec->sclass);
        if (rc)
                return rc;

        return avc_has_perm(newsid,
                            sbsec->sid,
                            SECCLASS_FILESYSTEM,
                            FILESYSTEM__ASSOCIATE,
                            &ad);
}

static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
                                        const void *value, size_t size,
                                        int flags)
{
        struct inode *inode = d_backing_inode(dentry);
        struct inode_security_struct *isec = inode->i_security;
        u32 newsid;
        int rc;

        if (strcmp(name, XATTR_NAME_SELINUX)) {
                /* Not an attribute we recognize, so nothing to do. */
                return;
        }

        rc = security_context_to_sid_force(value, size, &newsid);
        if (rc) {
                printk(KERN_ERR "SELinux:  unable to map context to SID"
                       "for (%s, %lu), rc=%d\n",
                       inode->i_sb->s_id, inode->i_ino, -rc);
                return;
        }

        isec->sclass = inode_mode_to_security_class(inode->i_mode);
        isec->sid = newsid;
        isec->initialized = 1;

        return;
}

static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
{
        const struct cred *cred = current_cred();

        return dentry_has_perm(cred, dentry, FILE__GETATTR);
}

static int selinux_inode_listxattr(struct dentry *dentry)
{
        const struct cred *cred = current_cred();

        return dentry_has_perm(cred, dentry, FILE__GETATTR);
}

static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
{
        if (strcmp(name, XATTR_NAME_SELINUX))
                return selinux_inode_setotherxattr(dentry, name);

        /* No one is allowed to remove a SELinux security label.
           You can change the label, but all data must be labeled. */
        return -EACCES;
}

/*
 * Copy the inode security context value to the user.
 *
 * Permission check is handled by selinux_inode_getxattr hook.
 */
static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
{
        u32 size;
        int error;
        char *context = NULL;
        struct inode_security_struct *isec = inode->i_security;

        if (strcmp(name, XATTR_SELINUX_SUFFIX))
                return -EOPNOTSUPP;

        /*
         * If the caller has CAP_MAC_ADMIN, then get the raw context
         * value even if it is not defined by current policy; otherwise,
         * use the in-core value under current policy.
         * Use the non-auditing forms of the permission checks since
         * getxattr may be called by unprivileged processes commonly
         * and lack of permission just means that we fall back to the
         * in-core context value, not a denial.
         */
        error = selinux_capable(current_cred(), &init_user_ns, CAP_MAC_ADMIN,
                                SECURITY_CAP_NOAUDIT);
        if (!error)
                error = security_sid_to_context_force(isec->sid, &context,
                                                      &size);
        else
                error = security_sid_to_context(isec->sid, &context, &size);
        if (error)
                return error;
        error = size;
        if (alloc) {
                *buffer = context;
                goto out_nofree;
        }
        kfree(context);
out_nofree:
        return error;
}

static int selinux_inode_setsecurity(struct inode *inode, const char *name,
                                     const void *value, size_t size, int flags)
{
        struct inode_security_struct *isec = inode->i_security;
        u32 newsid;
        int rc;

        if (strcmp(name, XATTR_SELINUX_SUFFIX))
                return -EOPNOTSUPP;

        if (!value || !size)
                return -EACCES;

        rc = security_context_to_sid((void *)value, size, &newsid, GFP_KERNEL);
        if (rc)
                return rc;

        isec->sclass = inode_mode_to_security_class(inode->i_mode);
        isec->sid = newsid;
        isec->initialized = 1;
        return 0;
}

static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
{
        const int len = sizeof(XATTR_NAME_SELINUX);
        if (buffer && len <= buffer_size)
                memcpy(buffer, XATTR_NAME_SELINUX, len);
        return len;
}

static void selinux_inode_getsecid(const struct inode *inode, u32 *secid)
{
        struct inode_security_struct *isec = inode->i_security;
        *secid = isec->sid;
}

/* file security operations */

static int selinux_revalidate_file_permission(struct file *file, int mask)
{
        const struct cred *cred = current_cred();
        struct inode *inode = file_inode(file);

        /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
        if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
                mask |= MAY_APPEND;

        return file_has_perm(cred, file,
                             file_mask_to_av(inode->i_mode, mask));
}

static int selinux_file_permission(struct file *file, int mask)
{
        struct inode *inode = file_inode(file);
        struct file_security_struct *fsec = file->f_security;
        struct inode_security_struct *isec = inode->i_security;
        u32 sid = current_sid();

        if (!mask)
                /* No permission to check.  Existence test. */
                return 0;

        if (sid == fsec->sid && fsec->isid == isec->sid &&
            fsec->pseqno == avc_policy_seqno())
                /* No change since file_open check. */
                return 0;

        return selinux_revalidate_file_permission(file, mask);
}

static int selinux_file_alloc_security(struct file *file)
{
        return file_alloc_security(file);
}

static void selinux_file_free_security(struct file *file)
{
        file_free_security(file);
}

static int selinux_file_ioctl(struct file *file, unsigned int cmd,
                              unsigned long arg)
{
        const struct cred *cred = current_cred();
        int error = 0;

        switch (cmd) {
        case FIONREAD:
        /* fall through */
        case FIBMAP:
        /* fall through */
        case FIGETBSZ:
        /* fall through */
        case FS_IOC_GETFLAGS:
        /* fall through */
        case FS_IOC_GETVERSION:
                error = file_has_perm(cred, file, FILE__GETATTR);
                break;

        case FS_IOC_SETFLAGS:
        /* fall through */
        case FS_IOC_SETVERSION:
                error = file_has_perm(cred, file, FILE__SETATTR);
                break;

        /* sys_ioctl() checks */
        case FIONBIO:
        /* fall through */
        case FIOASYNC:
                error = file_has_perm(cred, file, 0);
                break;

        case KDSKBENT:
        case KDSKBSENT:
                error = cred_has_capability(cred, CAP_SYS_TTY_CONFIG,
                                            SECURITY_CAP_AUDIT);
                break;

        /* default case assumes that the command will go
         * to the file's ioctl() function.
         */
        default:
                error = file_has_perm(cred, file, FILE__IOCTL);
        }
        return error;
}

static int default_noexec;

static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
{
        const struct cred *cred = current_cred();
        int rc = 0;

        if (default_noexec &&
            (prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
                /*
                 * We are making executable an anonymous mapping or a
                 * private file mapping that will also be writable.
                 * This has an additional check.
                 */
                rc = cred_has_perm(cred, cred, PROCESS__EXECMEM);
                if (rc)
                        goto error;
        }

        if (file) {
                /* read access is always possible with a mapping */
                u32 av = FILE__READ;

                /* write access only matters if the mapping is shared */
                if (shared && (prot & PROT_WRITE))
                        av |= FILE__WRITE;

                if (prot & PROT_EXEC)
                        av |= FILE__EXECUTE;

                return file_has_perm(cred, file, av);
        }

error:
        return rc;
}

static int selinux_mmap_addr(unsigned long addr)
{
        int rc;

        /* do DAC check on address space usage */
        rc = cap_mmap_addr(addr);
        if (rc)
                return rc;

        if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
                u32 sid = current_sid();
                rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
                                  MEMPROTECT__MMAP_ZERO, NULL);
        }

        return rc;
}

static int selinux_mmap_file(struct file *file, unsigned long reqprot,
                             unsigned long prot, unsigned long flags)
{
        if (selinux_checkreqprot)
                prot = reqprot;

        return file_map_prot_check(file, prot,
                                   (flags & MAP_TYPE) == MAP_SHARED);
}

static int selinux_file_mprotect(struct vm_area_struct *vma,
                                 unsigned long reqprot,
                                 unsigned long prot)
{
        const struct cred *cred = current_cred();

        if (selinux_checkreqprot)
                prot = reqprot;

        if (default_noexec &&
            (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
                int rc = 0;
                if (vma->vm_start >= vma->vm_mm->start_brk &&
                    vma->vm_end <= vma->vm_mm->brk) {
                        rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
                } else if (!vma->vm_file &&
                           vma->vm_start <= vma->vm_mm->start_stack &&
                           vma->vm_end >= vma->vm_mm->start_stack) {
                        rc = current_has_perm(current, PROCESS__EXECSTACK);
                } else if (vma->vm_file && vma->anon_vma) {
                        /*
                         * We are making executable a file mapping that has
                         * had some COW done. Since pages might have been
                         * written, check ability to execute the possibly
                         * modified content.  This typically should only
                         * occur for text relocations.
                         */
                        rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD);
                }
                if (rc)
                        return rc;
        }

        return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
}

static int selinux_file_lock(struct file *file, unsigned int cmd)
{
        const struct cred *cred = current_cred();

        return file_has_perm(cred, file, FILE__LOCK);
}

static int selinux_file_fcntl(struct file *file, unsigned int cmd,
                              unsigned long arg)
{
        const struct cred *cred = current_cred();
        int err = 0;

        switch (cmd) {
        case F_SETFL:
                if ((file->f_flags & O_APPEND) && !(arg & O_APPEND)) {
                        err = file_has_perm(cred, file, FILE__WRITE);
                        break;
                }
                /* fall through */
        case F_SETOWN:
        case F_SETSIG:
        case F_GETFL:
        case F_GETOWN:
        case F_GETSIG:
        case F_GETOWNER_UIDS:
                /* Just check FD__USE permission */
                err = file_has_perm(cred, file, 0);
                break;
        case F_GETLK:
        case F_SETLK:
        case F_SETLKW:
        case F_OFD_GETLK:
        case F_OFD_SETLK:
        case F_OFD_SETLKW:
#if BITS_PER_LONG == 32
        case F_GETLK64:
        case F_SETLK64:
        case F_SETLKW64:
#endif
                err = file_has_perm(cred, file, FILE__LOCK);
                break;
        }

        return err;
}

static void selinux_file_set_fowner(struct file *file)
{
        struct file_security_struct *fsec;

        fsec = file->f_security;
        fsec->fown_sid = current_sid();
}

static int selinux_file_send_sigiotask(struct task_struct *tsk,
                                       struct fown_struct *fown, int signum)
{
        struct file *file;
        u32 sid = task_sid(tsk);
        u32 perm;
        struct file_security_struct *fsec;

        /* struct fown_struct is never outside the context of a struct file */
        file = container_of(fown, struct file, f_owner);

        fsec = file->f_security;

        if (!signum)
                perm = signal_to_av(SIGIO); /* as per send_sigio_to_task */
        else
                perm = signal_to_av(signum);

        return avc_has_perm(fsec->fown_sid, sid,
                            SECCLASS_PROCESS, perm, NULL);
}

static int selinux_file_receive(struct file *file)
{
        const struct cred *cred = current_cred();

        return file_has_perm(cred, file, file_to_av(file));
}

static int selinux_file_open(struct file *file, const struct cred *cred)
{
        struct file_security_struct *fsec;
        struct inode_security_struct *isec;

        fsec = file->f_security;
        isec = file_inode(file)->i_security;
        /*
         * Save inode label and policy sequence number
         * at open-time so that selinux_file_permission
         * can determine whether revalidation is necessary.
         * Task label is already saved in the file security
         * struct as its SID.
         */
        fsec->isid = isec->sid;
        fsec->pseqno = avc_policy_seqno();
        /*
         * Since the inode label or policy seqno may have changed
         * between the selinux_inode_permission check and the saving
         * of state above, recheck that access is still permitted.
         * Otherwise, access might never be revalidated against the
         * new inode label or new policy.
         * This check is not redundant - do not remove.
         */
        return file_path_has_perm(cred, file, open_file_to_av(file));
}

/* task security operations */

static int selinux_task_create(unsigned long clone_flags)
{
        return current_has_perm(current, PROCESS__FORK);
}

/*
 * allocate the SELinux part of blank credentials
 */
static int selinux_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
        struct task_security_struct *tsec;

        tsec = kzalloc(sizeof(struct task_security_struct), gfp);
        if (!tsec)
                return -ENOMEM;

        cred->security = tsec;
        return 0;
}

/*
 * detach and free the LSM part of a set of credentials
 */
static void selinux_cred_free(struct cred *cred)
{
        struct task_security_struct *tsec = cred->security;

        /*
         * cred->security == NULL if security_cred_alloc_blank() or
         * security_prepare_creds() returned an error.
         */
        BUG_ON(cred->security && (unsigned long) cred->security < PAGE_SIZE);
        cred->security = (void *) 0x7UL;
        kfree(tsec);
}

/*
 * prepare a new set of credentials for modification
 */
static int selinux_cred_prepare(struct cred *new, const struct cred *old,
                                gfp_t gfp)
{
        const struct task_security_struct *old_tsec;
        struct task_security_struct *tsec;

        old_tsec = old->security;

        tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp);
        if (!tsec)
                return -ENOMEM;

        new->security = tsec;
        return 0;
}

/*
 * transfer the SELinux data to a blank set of creds
 */
static void selinux_cred_transfer(struct cred *new, const struct cred *old)
{
        const struct task_security_struct *old_tsec = old->security;
        struct task_security_struct *tsec = new->security;

        *tsec = *old_tsec;
}

/*
 * set the security data for a kernel service
 * - all the creation contexts are set to unlabelled
 */
static int selinux_kernel_act_as(struct cred *new, u32 secid)
{
        struct task_security_struct *tsec = new->security;
        u32 sid = current_sid();
        int ret;

        ret = avc_has_perm(sid, secid,
                           SECCLASS_KERNEL_SERVICE,
                           KERNEL_SERVICE__USE_AS_OVERRIDE,
                           NULL);
        if (ret == 0) {
                tsec->sid = secid;
                tsec->create_sid = 0;
                tsec->keycreate_sid = 0;
                tsec->sockcreate_sid = 0;
        }
        return ret;
}

/*
 * set the file creation context in a security record to the same as the
 * objective context of the specified inode
 */
static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode)
{
        struct inode_security_struct *isec = inode->i_security;
        struct task_security_struct *tsec = new->security;
        u32 sid = current_sid();
        int ret;

        ret = avc_has_perm(sid, isec->sid,
                           SECCLASS_KERNEL_SERVICE,
                           KERNEL_SERVICE__CREATE_FILES_AS,
                           NULL);

        if (ret == 0)
                tsec->create_sid = isec->sid;
        return ret;
}

static int selinux_kernel_module_request(char *kmod_name)
{
        u32 sid;
        struct common_audit_data ad;

        sid = task_sid(current);

        ad.type = LSM_AUDIT_DATA_KMOD;
        ad.u.kmod_name = kmod_name;

        return avc_has_perm(sid, SECINITSID_KERNEL, SECCLASS_SYSTEM,
                            SYSTEM__MODULE_REQUEST, &ad);
}

static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)
{
        return current_has_perm(p, PROCESS__SETPGID);
}

static int selinux_task_getpgid(struct task_struct *p)
{
        return current_has_perm(p, PROCESS__GETPGID);
}

static int selinux_task_getsid(struct task_struct *p)
{
        return current_has_perm(p, PROCESS__GETSESSION);
}

static void selinux_task_getsecid(struct task_struct *p, u32 *secid)
{
        *secid = task_sid(p);
}

static int selinux_task_setnice(struct task_struct *p, int nice)
{
        int rc;

        rc = cap_task_setnice(p, nice);
        if (rc)
                return rc;

        return current_has_perm(p, PROCESS__SETSCHED);
}

static int selinux_task_setioprio(struct task_struct *p, int ioprio)
{
        int rc;

        rc = cap_task_setioprio(p, ioprio);
        if (rc)
                return rc;

        return current_has_perm(p, PROCESS__SETSCHED);
}

static int selinux_task_getioprio(struct task_struct *p)
{
        return current_has_perm(p, PROCESS__GETSCHED);
}

static int selinux_task_setrlimit(struct task_struct *p, unsigned int resource,
                struct rlimit *new_rlim)
{
        struct rlimit *old_rlim = p->signal->rlim + resource;

        /* Control the ability to change the hard limit (whether
           lowering or raising it), so that the hard limit can
           later be used as a safe reset point for the soft limit
           upon context transitions.  See selinux_bprm_committing_creds. */
        if (old_rlim->rlim_max != new_rlim->rlim_max)
                return current_has_perm(p, PROCESS__SETRLIMIT);

        return 0;
}

static int selinux_task_setscheduler(struct task_struct *p)
{
        int rc;

        rc = cap_task_setscheduler(p);
        if (rc)
                return rc;

        return current_has_perm(p, PROCESS__SETSCHED);
}

static int selinux_task_getscheduler(struct task_struct *p)
{
        return current_has_perm(p, PROCESS__GETSCHED);
}

static int selinux_task_movememory(struct task_struct *p)
{
        return current_has_perm(p, PROCESS__SETSCHED);
}

static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
                                int sig, u32 secid)
{
        u32 perm;
        int rc;

        if (!sig)
                perm = PROCESS__SIGNULL; /* null signal; existence test */
        else
                perm = signal_to_av(sig);
        if (secid)
                rc = avc_has_perm(secid, task_sid(p),
                                  SECCLASS_PROCESS, perm, NULL);
        else
                rc = current_has_perm(p, perm);
        return rc;
}

static int selinux_task_wait(struct task_struct *p)
{
        return task_has_perm(p, current, PROCESS__SIGCHLD);
}

static void selinux_task_to_inode(struct task_struct *p,
                                  struct inode *inode)
{
        struct inode_security_struct *isec = inode->i_security;
        u32 sid = task_sid(p);

        isec->sid = sid;
        isec->initialized = 1;
}

/* Returns error only if unable to parse addresses */
static int selinux_parse_skb_ipv4(struct sk_buff *skb,
                        struct common_audit_data *ad, u8 *proto)
{
        int offset, ihlen, ret = -EINVAL;
        struct iphdr _iph, *ih;

        offset = skb_network_offset(skb);
        ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
        if (ih == NULL)
                goto out;

        ihlen = ih->ihl * 4;
        if (ihlen < sizeof(_iph))
                goto out;

        ad->u.net->v4info.saddr = ih->saddr;
        ad->u.net->v4info.daddr = ih->daddr;
        ret = 0;

        if (proto)
                *proto = ih->protocol;

        switch (ih->protocol) {
        case IPPROTO_TCP: {
                struct tcphdr _tcph, *th;

                if (ntohs(ih->frag_off) & IP_OFFSET)
                        break;

                offset += ihlen;
                th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
                if (th == NULL)
                        break;

                ad->u.net->sport = th->source;
                ad->u.net->dport = th->dest;
                break;
        }

        case IPPROTO_UDP: {
                struct udphdr _udph, *uh;

                if (ntohs(ih->frag_off) & IP_OFFSET)
                        break;

                offset += ihlen;
                uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
                if (uh == NULL)
                        break;

                ad->u.net->sport = uh->source;
                ad->u.net->dport = uh->dest;
                break;
        }

        case IPPROTO_DCCP: {
                struct dccp_hdr _dccph, *dh;

                if (ntohs(ih->frag_off) & IP_OFFSET)
                        break;

                offset += ihlen;
                dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
                if (dh == NULL)
                        break;

                ad->u.net->sport = dh->dccph_sport;
                ad->u.net->dport = dh->dccph_dport;
                break;
        }

        default:
                break;
        }
out:
        return ret;
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

/* Returns error only if unable to parse addresses */
static int selinux_parse_skb_ipv6(struct sk_buff *skb,
                        struct common_audit_data *ad, u8 *proto)
{
        u8 nexthdr;
        int ret = -EINVAL, offset;
        struct ipv6hdr _ipv6h, *ip6;
        __be16 frag_off;

        offset = skb_network_offset(skb);
        ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
        if (ip6 == NULL)
                goto out;

        ad->u.net->v6info.saddr = ip6->saddr;
        ad->u.net->v6info.daddr = ip6->daddr;
        ret = 0;

        nexthdr = ip6->nexthdr;
        offset += sizeof(_ipv6h);
        offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
        if (offset < 0)
                goto out;

        if (proto)
                *proto = nexthdr;

        switch (nexthdr) {
        case IPPROTO_TCP: {
                struct tcphdr _tcph, *th;

                th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
                if (th == NULL)
                        break;

                ad->u.net->sport = th->source;
                ad->u.net->dport = th->dest;
                break;
        }

        case IPPROTO_UDP: {
                struct udphdr _udph, *uh;

                uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
                if (uh == NULL)
                        break;

                ad->u.net->sport = uh->source;
                ad->u.net->dport = uh->dest;
                break;
        }

        case IPPROTO_DCCP: {
                struct dccp_hdr _dccph, *dh;

                dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
                if (dh == NULL)
                        break;

                ad->u.net->sport = dh->dccph_sport;
                ad->u.net->dport = dh->dccph_dport;
                break;
        }

        /* includes fragments */
        default:
                break;
        }
out:
        return ret;
}

#endif /* IPV6 */

static int selinux_parse_skb(struct sk_buff *skb, struct common_audit_data *ad,
                             char **_addrp, int src, u8 *proto)
{
        char *addrp;
        int ret;

        switch (ad->u.net->family) {
        case PF_INET:
                ret = selinux_parse_skb_ipv4(skb, ad, proto);
                if (ret)
                        goto parse_error;
                addrp = (char *)(src ? &ad->u.net->v4info.saddr :
                                       &ad->u.net->v4info.daddr);
                goto okay;

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
        case PF_INET6:
                ret = selinux_parse_skb_ipv6(skb, ad, proto);
                if (ret)
                        goto parse_error;
                addrp = (char *)(src ? &ad->u.net->v6info.saddr :
                                       &ad->u.net->v6info.daddr);
                goto okay;
#endif  /* IPV6 */
        default:
                addrp = NULL;
                goto okay;
        }

parse_error:
        printk(KERN_WARNING
               "SELinux: failure in selinux_parse_skb(),"
               " unable to parse packet\n");
        return ret;

okay:
        if (_addrp)
                *_addrp = addrp;
        return 0;
}

/**
 * selinux_skb_peerlbl_sid - Determine the peer label of a packet
 * @skb: the packet
 * @family: protocol family
 * @sid: the packet's peer label SID
 *
 * Description:
 * Check the various different forms of network peer labeling and determine
 * the peer label/SID for the packet; most of the magic actually occurs in
 * the security server function security_net_peersid_cmp().  The function
 * returns zero if the value in @sid is valid (although it may be SECSID_NULL)
 * or -EACCES if @sid is invalid due to inconsistencies with the different
 * peer labels.
 *
 */
static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
{
        int err;
        u32 xfrm_sid;
        u32 nlbl_sid;
        u32 nlbl_type;

        err = selinux_xfrm_skb_sid(skb, &xfrm_sid);
        if (unlikely(err))
                return -EACCES;
        err = selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
        if (unlikely(err))
                return -EACCES;

        err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid);
        if (unlikely(err)) {
                printk(KERN_WARNING
                       "SELinux: failure in selinux_skb_peerlbl_sid(),"
                       " unable to determine packet's peer label\n");
                return -EACCES;
        }

        return 0;
}

/**
 * selinux_conn_sid - Determine the child socket label for a connection
 * @sk_sid: the parent socket's SID
 * @skb_sid: the packet's SID
 * @conn_sid: the resulting connection SID
 *
 * If @skb_sid is valid then the user:role:type information from @sk_sid is
 * combined with the MLS information from @skb_sid in order to create
 * @conn_sid.  If @skb_sid is not valid then then @conn_sid is simply a copy
 * of @sk_sid.  Returns zero on success, negative values on failure.
 *
 */
static int selinux_conn_sid(u32 sk_sid, u32 skb_sid, u32 *conn_sid)
{
        int err = 0;

        if (skb_sid != SECSID_NULL)
                err = security_sid_mls_copy(sk_sid, skb_sid, conn_sid);
        else
                *conn_sid = sk_sid;

        return err;
}

/* socket security operations */

static int socket_sockcreate_sid(const struct task_security_struct *tsec,
                                 u16 secclass, u32 *socksid)
{
        if (tsec->sockcreate_sid > SECSID_NULL) {
                *socksid = tsec->sockcreate_sid;
                return 0;
        }

        return security_transition_sid(tsec->sid, tsec->sid, secclass, NULL,
                                       socksid);
}

static int sock_has_perm(struct task_struct *task, struct sock *sk, u32 perms)
{
        struct sk_security_struct *sksec = sk->sk_security;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        u32 tsid = task_sid(task);

        if (sksec->sid == SECINITSID_KERNEL)
                return 0;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->sk = sk;

        return avc_has_perm(tsid, sksec->sid, sksec->sclass, perms, &ad);
}

static int selinux_socket_create(int family, int type,
                                 int protocol, int kern)
{
        const struct task_security_struct *tsec = current_security();
        u32 newsid;
        u16 secclass;
        int rc;

        if (kern)
                return 0;

        secclass = socket_type_to_security_class(family, type, protocol);
        rc = socket_sockcreate_sid(tsec, secclass, &newsid);
        if (rc)
                return rc;

        return avc_has_perm(tsec->sid, newsid, secclass, SOCKET__CREATE, NULL);
}

static int selinux_socket_post_create(struct socket *sock, int family,
                                      int type, int protocol, int kern)
{
        const struct task_security_struct *tsec = current_security();
        struct inode_security_struct *isec = SOCK_INODE(sock)->i_security;
        struct sk_security_struct *sksec;
        int err = 0;

        isec->sclass = socket_type_to_security_class(family, type, protocol);

        if (kern)
                isec->sid = SECINITSID_KERNEL;
        else {
                err = socket_sockcreate_sid(tsec, isec->sclass, &(isec->sid));
                if (err)
                        return err;
        }

        isec->initialized = 1;

        if (sock->sk) {
                sksec = sock->sk->sk_security;
                sksec->sid = isec->sid;
                sksec->sclass = isec->sclass;
                err = selinux_netlbl_socket_post_create(sock->sk, family);
        }

        return err;
}

/* Range of port numbers used to automatically bind.
   Need to determine whether we should perform a name_bind
   permission check between the socket and the port number. */

static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
{
        struct sock *sk = sock->sk;
        u16 family;
        int err;

        err = sock_has_perm(current, sk, SOCKET__BIND);
        if (err)
                goto out;

        /*
         * If PF_INET or PF_INET6, check name_bind permission for the port.
         * Multiple address binding for SCTP is not supported yet: we just
         * check the first address now.
         */
        family = sk->sk_family;
        if (family == PF_INET || family == PF_INET6) {
                char *addrp;
                struct sk_security_struct *sksec = sk->sk_security;
                struct common_audit_data ad;
                struct lsm_network_audit net = {0,};
                struct sockaddr_in *addr4 = NULL;
                struct sockaddr_in6 *addr6 = NULL;
                unsigned short snum;
                u32 sid, node_perm;

                if (family == PF_INET) {
                        addr4 = (struct sockaddr_in *)address;
                        snum = ntohs(addr4->sin_port);
                        addrp = (char *)&addr4->sin_addr.s_addr;
                } else {
                        addr6 = (struct sockaddr_in6 *)address;
                        snum = ntohs(addr6->sin6_port);
                        addrp = (char *)&addr6->sin6_addr.s6_addr;
                }

                if (snum) {
                        int low, high;

                        inet_get_local_port_range(sock_net(sk), &low, &high);

                        if (snum < max(PROT_SOCK, low) || snum > high) {
                                err = sel_netport_sid(sk->sk_protocol,
                                                      snum, &sid);
                                if (err)
                                        goto out;
                                ad.type = LSM_AUDIT_DATA_NET;
                                ad.u.net = &net;
                                ad.u.net->sport = htons(snum);
                                ad.u.net->family = family;
                                err = avc_has_perm(sksec->sid, sid,
                                                   sksec->sclass,
                                                   SOCKET__NAME_BIND, &ad);
                                if (err)
                                        goto out;
                        }
                }

                switch (sksec->sclass) {
                case SECCLASS_TCP_SOCKET:
                        node_perm = TCP_SOCKET__NODE_BIND;
                        break;

                case SECCLASS_UDP_SOCKET:
                        node_perm = UDP_SOCKET__NODE_BIND;
                        break;

                case SECCLASS_DCCP_SOCKET:
                        node_perm = DCCP_SOCKET__NODE_BIND;
                        break;

                default:
                        node_perm = RAWIP_SOCKET__NODE_BIND;
                        break;
                }

                err = sel_netnode_sid(addrp, family, &sid);
                if (err)
                        goto out;

                ad.type = LSM_AUDIT_DATA_NET;
                ad.u.net = &net;
                ad.u.net->sport = htons(snum);
                ad.u.net->family = family;

                if (family == PF_INET)
                        ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
                else
                        ad.u.net->v6info.saddr = addr6->sin6_addr;

                err = avc_has_perm(sksec->sid, sid,
                                   sksec->sclass, node_perm, &ad);
                if (err)
                        goto out;
        }
out:
        return err;
}

static int selinux_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen)
{
        struct sock *sk = sock->sk;
        struct sk_security_struct *sksec = sk->sk_security;
        int err;

        err = sock_has_perm(current, sk, SOCKET__CONNECT);
        if (err)
                return err;

        /*
         * If a TCP or DCCP socket, check name_connect permission for the port.
         */
        if (sksec->sclass == SECCLASS_TCP_SOCKET ||
            sksec->sclass == SECCLASS_DCCP_SOCKET) {
                struct common_audit_data ad;
                struct lsm_network_audit net = {0,};
                struct sockaddr_in *addr4 = NULL;
                struct sockaddr_in6 *addr6 = NULL;
                unsigned short snum;
                u32 sid, perm;

                if (sk->sk_family == PF_INET) {
                        addr4 = (struct sockaddr_in *)address;
                        if (addrlen < sizeof(struct sockaddr_in))
                                return -EINVAL;
                        snum = ntohs(addr4->sin_port);
                } else {
                        addr6 = (struct sockaddr_in6 *)address;
                        if (addrlen < SIN6_LEN_RFC2133)
                                return -EINVAL;
                        snum = ntohs(addr6->sin6_port);
                }

                err = sel_netport_sid(sk->sk_protocol, snum, &sid);
                if (err)
                        goto out;

                perm = (sksec->sclass == SECCLASS_TCP_SOCKET) ?
                       TCP_SOCKET__NAME_CONNECT : DCCP_SOCKET__NAME_CONNECT;

                ad.type = LSM_AUDIT_DATA_NET;
                ad.u.net = &net;
                ad.u.net->dport = htons(snum);
                ad.u.net->family = sk->sk_family;
                err = avc_has_perm(sksec->sid, sid, sksec->sclass, perm, &ad);
                if (err)
                        goto out;
        }

        err = selinux_netlbl_socket_connect(sk, address);

out:
        return err;
}

static int selinux_socket_listen(struct socket *sock, int backlog)
{
        return sock_has_perm(current, sock->sk, SOCKET__LISTEN);
}

static int selinux_socket_accept(struct socket *sock, struct socket *newsock)
{
        int err;
        struct inode_security_struct *isec;
        struct inode_security_struct *newisec;

        err = sock_has_perm(current, sock->sk, SOCKET__ACCEPT);
        if (err)
                return err;

        newisec = SOCK_INODE(newsock)->i_security;

        isec = SOCK_INODE(sock)->i_security;
        newisec->sclass = isec->sclass;
        newisec->sid = isec->sid;
        newisec->initialized = 1;

        return 0;
}

static int selinux_socket_sendmsg(struct socket *sock, struct msghdr *msg,
                                  int size)
{
        return sock_has_perm(current, sock->sk, SOCKET__WRITE);
}

static int selinux_socket_recvmsg(struct socket *sock, struct msghdr *msg,
                                  int size, int flags)
{
        return sock_has_perm(current, sock->sk, SOCKET__READ);
}

static int selinux_socket_getsockname(struct socket *sock)
{
        return sock_has_perm(current, sock->sk, SOCKET__GETATTR);
}

static int selinux_socket_getpeername(struct socket *sock)
{
        return sock_has_perm(current, sock->sk, SOCKET__GETATTR);
}

static int selinux_socket_setsockopt(struct socket *sock, int level, int optname)
{
        int err;

        err = sock_has_perm(current, sock->sk, SOCKET__SETOPT);
        if (err)
                return err;

        return selinux_netlbl_socket_setsockopt(sock, level, optname);
}

static int selinux_socket_getsockopt(struct socket *sock, int level,
                                     int optname)
{
        return sock_has_perm(current, sock->sk, SOCKET__GETOPT);
}

static int selinux_socket_shutdown(struct socket *sock, int how)
{
        return sock_has_perm(current, sock->sk, SOCKET__SHUTDOWN);
}

static int selinux_socket_unix_stream_connect(struct sock *sock,
                                              struct sock *other,
                                              struct sock *newsk)
{
        struct sk_security_struct *sksec_sock = sock->sk_security;
        struct sk_security_struct *sksec_other = other->sk_security;
        struct sk_security_struct *sksec_new = newsk->sk_security;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        int err;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->sk = other;

        err = avc_has_perm(sksec_sock->sid, sksec_other->sid,
                           sksec_other->sclass,
                           UNIX_STREAM_SOCKET__CONNECTTO, &ad);
        if (err)
                return err;

        /* server child socket */
        sksec_new->peer_sid = sksec_sock->sid;
        err = security_sid_mls_copy(sksec_other->sid, sksec_sock->sid,
                                    &sksec_new->sid);
        if (err)
                return err;

        /* connecting socket */
        sksec_sock->peer_sid = sksec_new->sid;

        return 0;
}

static int selinux_socket_unix_may_send(struct socket *sock,
                                        struct socket *other)
{
        struct sk_security_struct *ssec = sock->sk->sk_security;
        struct sk_security_struct *osec = other->sk->sk_security;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->sk = other->sk;

        return avc_has_perm(ssec->sid, osec->sid, osec->sclass, SOCKET__SENDTO,
                            &ad);
}

static int selinux_inet_sys_rcv_skb(struct net *ns, int ifindex,
                                    char *addrp, u16 family, u32 peer_sid,
                                    struct common_audit_data *ad)
{
        int err;
        u32 if_sid;
        u32 node_sid;

        err = sel_netif_sid(ns, ifindex, &if_sid);
        if (err)
                return err;
        err = avc_has_perm(peer_sid, if_sid,
                           SECCLASS_NETIF, NETIF__INGRESS, ad);
        if (err)
                return err;

        err = sel_netnode_sid(addrp, family, &node_sid);
        if (err)
                return err;
        return avc_has_perm(peer_sid, node_sid,
                            SECCLASS_NODE, NODE__RECVFROM, ad);
}

static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
                                       u16 family)
{
        int err = 0;
        struct sk_security_struct *sksec = sk->sk_security;
        u32 sk_sid = sksec->sid;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        char *addrp;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->netif = skb->skb_iif;
        ad.u.net->family = family;
        err = selinux_parse_skb(skb, &ad, &addrp, 1, NULL);
        if (err)
                return err;

        if (selinux_secmark_enabled()) {
                err = avc_has_perm(sk_sid, skb->secmark, SECCLASS_PACKET,
                                   PACKET__RECV, &ad);
                if (err)
                        return err;
        }

        err = selinux_netlbl_sock_rcv_skb(sksec, skb, family, &ad);
        if (err)
                return err;
        err = selinux_xfrm_sock_rcv_skb(sksec->sid, skb, &ad);

        return err;
}

static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        int err;
        struct sk_security_struct *sksec = sk->sk_security;
        u16 family = sk->sk_family;
        u32 sk_sid = sksec->sid;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        char *addrp;
        u8 secmark_active;
        u8 peerlbl_active;

        if (family != PF_INET && family != PF_INET6)
                return 0;

        /* Handle mapped IPv4 packets arriving via IPv6 sockets */
        if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
                family = PF_INET;

        /* If any sort of compatibility mode is enabled then handoff processing
         * to the selinux_sock_rcv_skb_compat() function to deal with the
         * special handling.  We do this in an attempt to keep this function
         * as fast and as clean as possible. */
        if (!selinux_policycap_netpeer)
                return selinux_sock_rcv_skb_compat(sk, skb, family);

        secmark_active = selinux_secmark_enabled();
        peerlbl_active = selinux_peerlbl_enabled();
        if (!secmark_active && !peerlbl_active)
                return 0;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->netif = skb->skb_iif;
        ad.u.net->family = family;
        err = selinux_parse_skb(skb, &ad, &addrp, 1, NULL);
        if (err)
                return err;

        if (peerlbl_active) {
                u32 peer_sid;

                err = selinux_skb_peerlbl_sid(skb, family, &peer_sid);
                if (err)
                        return err;
                err = selinux_inet_sys_rcv_skb(sock_net(sk), skb->skb_iif,
                                               addrp, family, peer_sid, &ad);
                if (err) {
                        selinux_netlbl_err(skb, err, 0);
                        return err;
                }
                err = avc_has_perm(sk_sid, peer_sid, SECCLASS_PEER,
                                   PEER__RECV, &ad);
                if (err) {
                        selinux_netlbl_err(skb, err, 0);
                        return err;
                }
        }

        if (secmark_active) {
                err = avc_has_perm(sk_sid, skb->secmark, SECCLASS_PACKET,
                                   PACKET__RECV, &ad);
                if (err)
                        return err;
        }

        return err;
}

static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *optval,
                                            int __user *optlen, unsigned len)
{
        int err = 0;
        char *scontext;
        u32 scontext_len;
        struct sk_security_struct *sksec = sock->sk->sk_security;
        u32 peer_sid = SECSID_NULL;

        if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
            sksec->sclass == SECCLASS_TCP_SOCKET)
                peer_sid = sksec->peer_sid;
        if (peer_sid == SECSID_NULL)
                return -ENOPROTOOPT;

        err = security_sid_to_context(peer_sid, &scontext, &scontext_len);
        if (err)
                return err;

        if (scontext_len > len) {
                err = -ERANGE;
                goto out_len;
        }

        if (copy_to_user(optval, scontext, scontext_len))
                err = -EFAULT;

out_len:
        if (put_user(scontext_len, optlen))
                err = -EFAULT;
        kfree(scontext);
        return err;
}

static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
{
        u32 peer_secid = SECSID_NULL;
        u16 family;

        if (skb && skb->protocol == htons(ETH_P_IP))
                family = PF_INET;
        else if (skb && skb->protocol == htons(ETH_P_IPV6))
                family = PF_INET6;
        else if (sock)
                family = sock->sk->sk_family;
        else
                goto out;

        if (sock && family == PF_UNIX)
                selinux_inode_getsecid(SOCK_INODE(sock), &peer_secid);
        else if (skb)
                selinux_skb_peerlbl_sid(skb, family, &peer_secid);

out:
        *secid = peer_secid;
        if (peer_secid == SECSID_NULL)
                return -EINVAL;
        return 0;
}

static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
{
        struct sk_security_struct *sksec;

        sksec = kzalloc(sizeof(*sksec), priority);
        if (!sksec)
                return -ENOMEM;

        sksec->peer_sid = SECINITSID_UNLABELED;
        sksec->sid = SECINITSID_UNLABELED;
        selinux_netlbl_sk_security_reset(sksec);
        sk->sk_security = sksec;

        return 0;
}

static void selinux_sk_free_security(struct sock *sk)
{
        struct sk_security_struct *sksec = sk->sk_security;

        sk->sk_security = NULL;
        selinux_netlbl_sk_security_free(sksec);
        kfree(sksec);
}

static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk)
{
        struct sk_security_struct *sksec = sk->sk_security;
        struct sk_security_struct *newsksec = newsk->sk_security;

        newsksec->sid = sksec->sid;
        newsksec->peer_sid = sksec->peer_sid;
        newsksec->sclass = sksec->sclass;

        selinux_netlbl_sk_security_reset(newsksec);
}

static void selinux_sk_getsecid(struct sock *sk, u32 *secid)
{
        if (!sk)
                *secid = SECINITSID_ANY_SOCKET;
        else {
                struct sk_security_struct *sksec = sk->sk_security;

                *secid = sksec->sid;
        }
}

static void selinux_sock_graft(struct sock *sk, struct socket *parent)
{
        struct inode_security_struct *isec = SOCK_INODE(parent)->i_security;
        struct sk_security_struct *sksec = sk->sk_security;

        if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 ||
            sk->sk_family == PF_UNIX)
                isec->sid = sksec->sid;
        sksec->sclass = isec->sclass;
}

static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
                                     struct request_sock *req)
{
        struct sk_security_struct *sksec = sk->sk_security;
        int err;
        u16 family = req->rsk_ops->family;
        u32 connsid;
        u32 peersid;

        err = selinux_skb_peerlbl_sid(skb, family, &peersid);
        if (err)
                return err;
        err = selinux_conn_sid(sksec->sid, peersid, &connsid);
        if (err)
                return err;
        req->secid = connsid;
        req->peer_secid = peersid;

        return selinux_netlbl_inet_conn_request(req, family);
}

static void selinux_inet_csk_clone(struct sock *newsk,
                                   const struct request_sock *req)
{
        struct sk_security_struct *newsksec = newsk->sk_security;

        newsksec->sid = req->secid;
        newsksec->peer_sid = req->peer_secid;
        /* NOTE: Ideally, we should also get the isec->sid for the
           new socket in sync, but we don't have the isec available yet.
           So we will wait until sock_graft to do it, by which
           time it will have been created and available. */

        /* We don't need to take any sort of lock here as we are the only
         * thread with access to newsksec */
        selinux_netlbl_inet_csk_clone(newsk, req->rsk_ops->family);
}

static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
{
        u16 family = sk->sk_family;
        struct sk_security_struct *sksec = sk->sk_security;

        /* handle mapped IPv4 packets arriving via IPv6 sockets */
        if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
                family = PF_INET;

        selinux_skb_peerlbl_sid(skb, family, &sksec->peer_sid);
}

static int selinux_secmark_relabel_packet(u32 sid)
{
        const struct task_security_struct *__tsec;
        u32 tsid;

        __tsec = current_security();
        tsid = __tsec->sid;

        return avc_has_perm(tsid, sid, SECCLASS_PACKET, PACKET__RELABELTO, NULL);
}

static void selinux_secmark_refcount_inc(void)
{
        atomic_inc(&selinux_secmark_refcount);
}

static void selinux_secmark_refcount_dec(void)
{
        atomic_dec(&selinux_secmark_refcount);
}

static void selinux_req_classify_flow(const struct request_sock *req,
                                      struct flowi *fl)
{
        fl->flowi_secid = req->secid;
}

static int selinux_tun_dev_alloc_security(void **security)
{
        struct tun_security_struct *tunsec;

        tunsec = kzalloc(sizeof(*tunsec), GFP_KERNEL);
        if (!tunsec)
                return -ENOMEM;
        tunsec->sid = current_sid();

        *security = tunsec;
        return 0;
}

static void selinux_tun_dev_free_security(void *security)
{
        kfree(security);
}

static int selinux_tun_dev_create(void)
{
        u32 sid = current_sid();

        /* we aren't taking into account the "sockcreate" SID since the socket
         * that is being created here is not a socket in the traditional sense,
         * instead it is a private sock, accessible only to the kernel, and
         * representing a wide range of network traffic spanning multiple
         * connections unlike traditional sockets - check the TUN driver to
         * get a better understanding of why this socket is special */

        return avc_has_perm(sid, sid, SECCLASS_TUN_SOCKET, TUN_SOCKET__CREATE,
                            NULL);
}

static int selinux_tun_dev_attach_queue(void *security)
{
        struct tun_security_struct *tunsec = security;

        return avc_has_perm(current_sid(), tunsec->sid, SECCLASS_TUN_SOCKET,
                            TUN_SOCKET__ATTACH_QUEUE, NULL);
}

static int selinux_tun_dev_attach(struct sock *sk, void *security)
{
        struct tun_security_struct *tunsec = security;
        struct sk_security_struct *sksec = sk->sk_security;

        /* we don't currently perform any NetLabel based labeling here and it
         * isn't clear that we would want to do so anyway; while we could apply
         * labeling without the support of the TUN user the resulting labeled
         * traffic from the other end of the connection would almost certainly
         * cause confusion to the TUN user that had no idea network labeling
         * protocols were being used */

        sksec->sid = tunsec->sid;
        sksec->sclass = SECCLASS_TUN_SOCKET;

        return 0;
}

static int selinux_tun_dev_open(void *security)
{
        struct tun_security_struct *tunsec = security;
        u32 sid = current_sid();
        int err;

        err = avc_has_perm(sid, tunsec->sid, SECCLASS_TUN_SOCKET,
                           TUN_SOCKET__RELABELFROM, NULL);
        if (err)
                return err;
        err = avc_has_perm(sid, sid, SECCLASS_TUN_SOCKET,
                           TUN_SOCKET__RELABELTO, NULL);
        if (err)
                return err;
        tunsec->sid = sid;

        return 0;
}

static int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
{
        int err = 0;
        u32 perm;
        struct nlmsghdr *nlh;
        struct sk_security_struct *sksec = sk->sk_security;

        if (skb->len < NLMSG_HDRLEN) {
                err = -EINVAL;
                goto out;
        }
        nlh = nlmsg_hdr(skb);

        err = selinux_nlmsg_lookup(sksec->sclass, nlh->nlmsg_type, &perm);
        if (err) {
                if (err == -EINVAL) {
                        printk(KERN_WARNING
                               "SELinux: unrecognized netlink message:"
                               " protocol=%hu nlmsg_type=%hu sclass=%hu\n",
                               sk->sk_protocol, nlh->nlmsg_type, sksec->sclass);
                        if (!selinux_enforcing || security_get_allow_unknown())
                                err = 0;
                }

                /* Ignore */
                if (err == -ENOENT)
                        err = 0;
                goto out;
        }

        err = sock_has_perm(current, sk, perm);
out:
        return err;
}

#ifdef CONFIG_NETFILTER

static unsigned int selinux_ip_forward(struct sk_buff *skb,
                                       const struct net_device *indev,
                                       u16 family)
{
        int err;
        char *addrp;
        u32 peer_sid;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        u8 secmark_active;
        u8 netlbl_active;
        u8 peerlbl_active;

        if (!selinux_policycap_netpeer)
                return NF_ACCEPT;

        secmark_active = selinux_secmark_enabled();
        netlbl_active = netlbl_enabled();
        peerlbl_active = selinux_peerlbl_enabled();
        if (!secmark_active && !peerlbl_active)
                return NF_ACCEPT;

        if (selinux_skb_peerlbl_sid(skb, family, &peer_sid) != 0)
                return NF_DROP;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->netif = indev->ifindex;
        ad.u.net->family = family;
        if (selinux_parse_skb(skb, &ad, &addrp, 1, NULL) != 0)
                return NF_DROP;

        if (peerlbl_active) {
                err = selinux_inet_sys_rcv_skb(dev_net(indev), indev->ifindex,
                                               addrp, family, peer_sid, &ad);
                if (err) {
                        selinux_netlbl_err(skb, err, 1);
                        return NF_DROP;
                }
        }

        if (secmark_active)
                if (avc_has_perm(peer_sid, skb->secmark,
                                 SECCLASS_PACKET, PACKET__FORWARD_IN, &ad))
                        return NF_DROP;

        if (netlbl_active)
                /* we do this in the FORWARD path and not the POST_ROUTING
                 * path because we want to make sure we apply the necessary
                 * labeling before IPsec is applied so we can leverage AH
                 * protection */
                if (selinux_netlbl_skbuff_setsid(skb, family, peer_sid) != 0)
                        return NF_DROP;

        return NF_ACCEPT;
}

static unsigned int selinux_ipv4_forward(const struct nf_hook_ops *ops,
                                         struct sk_buff *skb,
                                         const struct nf_hook_state *state)
{
        return selinux_ip_forward(skb, state->in, PF_INET);
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops,
                                         struct sk_buff *skb,
                                         const struct nf_hook_state *state)
{
        return selinux_ip_forward(skb, state->in, PF_INET6);
}
#endif  /* IPV6 */

static unsigned int selinux_ip_output(struct sk_buff *skb,
                                      u16 family)
{
        struct sock *sk;
        u32 sid;

        if (!netlbl_enabled())
                return NF_ACCEPT;

        /* we do this in the LOCAL_OUT path and not the POST_ROUTING path
         * because we want to make sure we apply the necessary labeling
         * before IPsec is applied so we can leverage AH protection */
        sk = skb->sk;
        if (sk) {
                struct sk_security_struct *sksec;

                if (sk->sk_state == TCP_LISTEN)
                        /* if the socket is the listening state then this
                         * packet is a SYN-ACK packet which means it needs to
                         * be labeled based on the connection/request_sock and
                         * not the parent socket.  unfortunately, we can't
                         * lookup the request_sock yet as it isn't queued on
                         * the parent socket until after the SYN-ACK is sent.
                         * the "solution" is to simply pass the packet as-is
                         * as any IP option based labeling should be copied
                         * from the initial connection request (in the IP
                         * layer).  it is far from ideal, but until we get a
                         * security label in the packet itself this is the
                         * best we can do. */
                        return NF_ACCEPT;

                /* standard practice, label using the parent socket */
                sksec = sk->sk_security;
                sid = sksec->sid;
        } else
                sid = SECINITSID_KERNEL;
        if (selinux_netlbl_skbuff_setsid(skb, family, sid) != 0)
                return NF_DROP;

        return NF_ACCEPT;
}

static unsigned int selinux_ipv4_output(const struct nf_hook_ops *ops,
                                        struct sk_buff *skb,
                                        const struct nf_hook_state *state)
{
        return selinux_ip_output(skb, PF_INET);
}

static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb,
                                                int ifindex,
                                                u16 family)
{
        struct sock *sk = skb->sk;
        struct sk_security_struct *sksec;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        char *addrp;
        u8 proto;

        if (sk == NULL)
                return NF_ACCEPT;
        sksec = sk->sk_security;

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->netif = ifindex;
        ad.u.net->family = family;
        if (selinux_parse_skb(skb, &ad, &addrp, 0, &proto))
                return NF_DROP;

        if (selinux_secmark_enabled())
                if (avc_has_perm(sksec->sid, skb->secmark,
                                 SECCLASS_PACKET, PACKET__SEND, &ad))
                        return NF_DROP_ERR(-ECONNREFUSED);

        if (selinux_xfrm_postroute_last(sksec->sid, skb, &ad, proto))
                return NF_DROP_ERR(-ECONNREFUSED);

        return NF_ACCEPT;
}

static unsigned int selinux_ip_postroute(struct sk_buff *skb,
                                         const struct net_device *outdev,
                                         u16 family)
{
        u32 secmark_perm;
        u32 peer_sid;
        int ifindex = outdev->ifindex;
        struct sock *sk;
        struct common_audit_data ad;
        struct lsm_network_audit net = {0,};
        char *addrp;
        u8 secmark_active;
        u8 peerlbl_active;

        /* If any sort of compatibility mode is enabled then handoff processing
         * to the selinux_ip_postroute_compat() function to deal with the
         * special handling.  We do this in an attempt to keep this function
         * as fast and as clean as possible. */
        if (!selinux_policycap_netpeer)
                return selinux_ip_postroute_compat(skb, ifindex, family);

        secmark_active = selinux_secmark_enabled();
        peerlbl_active = selinux_peerlbl_enabled();
        if (!secmark_active && !peerlbl_active)
                return NF_ACCEPT;

        sk = skb->sk;

#ifdef CONFIG_XFRM
        /* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec
         * packet transformation so allow the packet to pass without any checks
         * since we'll have another chance to perform access control checks
         * when the packet is on it's final way out.
         * NOTE: there appear to be some IPv6 multicast cases where skb->dst
         *       is NULL, in this case go ahead and apply access control.
         * NOTE: if this is a local socket (skb->sk != NULL) that is in the
         *       TCP listening state we cannot wait until the XFRM processing
         *       is done as we will miss out on the SA label if we do;
         *       unfortunately, this means more work, but it is only once per
         *       connection. */
        if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL &&
            !(sk != NULL && sk->sk_state == TCP_LISTEN))
                return NF_ACCEPT;
#endif

        if (sk == NULL) {
                /* Without an associated socket the packet is either coming
                 * from the kernel or it is being forwarded; check the packet
                 * to determine which and if the packet is being forwarded
                 * query the packet directly to determine the security label. */
                if (skb->skb_iif) {
                        secmark_perm = PACKET__FORWARD_OUT;
                        if (selinux_skb_peerlbl_sid(skb, family, &peer_sid))
                                return NF_DROP;
                } else {
                        secmark_perm = PACKET__SEND;
                        peer_sid = SECINITSID_KERNEL;
                }
        } else if (sk->sk_state == TCP_LISTEN) {
                /* Locally generated packet but the associated socket is in the
                 * listening state which means this is a SYN-ACK packet.  In
                 * this particular case the correct security label is assigned
                 * to the connection/request_sock but unfortunately we can't
                 * query the request_sock as it isn't queued on the parent
                 * socket until after the SYN-ACK packet is sent; the only
                 * viable choice is to regenerate the label like we do in
                 * selinux_inet_conn_request().  See also selinux_ip_output()
                 * for similar problems. */
                u32 skb_sid;
                struct sk_security_struct *sksec = sk->sk_security;
                if (selinux_skb_peerlbl_sid(skb, family, &skb_sid))
                        return NF_DROP;
                /* At this point, if the returned skb peerlbl is SECSID_NULL
                 * and the packet has been through at least one XFRM
                 * transformation then we must be dealing with the "final"
                 * form of labeled IPsec packet; since we've already applied
                 * all of our access controls on this packet we can safely
                 * pass the packet. */
                if (skb_sid == SECSID_NULL) {
                        switch (family) {
                        case PF_INET:
                                if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
                                        return NF_ACCEPT;
                                break;
                        case PF_INET6:
                                if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
                                        return NF_ACCEPT;
                                break;
                        default:
                                return NF_DROP_ERR(-ECONNREFUSED);
                        }
                }
                if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid))
                        return NF_DROP;
                secmark_perm = PACKET__SEND;
        } else {
                /* Locally generated packet, fetch the security label from the
                 * associated socket. */
                struct sk_security_struct *sksec = sk->sk_security;
                peer_sid = sksec->sid;
                secmark_perm = PACKET__SEND;
        }

        ad.type = LSM_AUDIT_DATA_NET;
        ad.u.net = &net;
        ad.u.net->netif = ifindex;
        ad.u.net->family = family;
        if (selinux_parse_skb(skb, &ad, &addrp, 0, NULL))
                return NF_DROP;

        if (secmark_active)
                if (avc_has_perm(peer_sid, skb->secmark,
                                 SECCLASS_PACKET, secmark_perm, &ad))
                        return NF_DROP_ERR(-ECONNREFUSED);

        if (peerlbl_active) {
                u32 if_sid;
                u32 node_sid;

                if (sel_netif_sid(dev_net(outdev), ifindex, &if_sid))
                        return NF_DROP;
                if (avc_has_perm(peer_sid, if_sid,
                                 SECCLASS_NETIF, NETIF__EGRESS, &ad))
                        return NF_DROP_ERR(-ECONNREFUSED);

                if (sel_netnode_sid(addrp, family, &node_sid))
                        return NF_DROP;
                if (avc_has_perm(peer_sid, node_sid,
                                 SECCLASS_NODE, NODE__SENDTO, &ad))
                        return NF_DROP_ERR(-ECONNREFUSED);
        }

        return NF_ACCEPT;
}

static unsigned int selinux_ipv4_postroute(const struct nf_hook_ops *ops,
                                           struct sk_buff *skb,
                                           const struct nf_hook_state *state)
{
        return selinux_ip_postroute(skb, state->out, PF_INET);
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static unsigned int selinux_ipv6_postroute(const struct nf_hook_ops *ops,
                                           struct sk_buff *skb,
                                           const struct nf_hook_state *state)
{
        return selinux_ip_postroute(skb, state->out, PF_INET6);
}
#endif  /* IPV6 */

#endif  /* CONFIG_NETFILTER */

static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb)
{
        int err;

        err = cap_netlink_send(sk, skb);
        if (err)
                return err;

        return selinux_nlmsg_perm(sk, skb);
}

static int ipc_alloc_security(struct task_struct *task,
                              struct kern_ipc_perm *perm,
                              u16 sclass)
{
        struct ipc_security_struct *isec;
        u32 sid;

        isec = kzalloc(sizeof(struct ipc_security_struct), GFP_KERNEL);
        if (!isec)
                return -ENOMEM;

        sid = task_sid(task);
        isec->sclass = sclass;
        isec->sid = sid;
        perm->security = isec;

        return 0;
}

static void ipc_free_security(struct kern_ipc_perm *perm)
{
        struct ipc_security_struct *isec = perm->security;
        perm->security = NULL;
        kfree(isec);
}

static int msg_msg_alloc_security(struct msg_msg *msg)
{
        struct msg_security_struct *msec;

        msec = kzalloc(sizeof(struct msg_security_struct), GFP_KERNEL);
        if (!msec)
                return -ENOMEM;

        msec->sid = SECINITSID_UNLABELED;
        msg->security = msec;

        return 0;
}

static void msg_msg_free_security(struct msg_msg *msg)
{
        struct msg_security_struct *msec = msg->security;

        msg->security = NULL;
        kfree(msec);
}

static int ipc_has_perm(struct kern_ipc_perm *ipc_perms,
                        u32 perms)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();

        isec = ipc_perms->security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = ipc_perms->key;

        return avc_has_perm(sid, isec->sid, isec->sclass, perms, &ad);
}

static int selinux_msg_msg_alloc_security(struct msg_msg *msg)
{
        return msg_msg_alloc_security(msg);
}

static void selinux_msg_msg_free_security(struct msg_msg *msg)
{
        msg_msg_free_security(msg);
}

/* message queue security operations */
static int selinux_msg_queue_alloc_security(struct msg_queue *msq)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        int rc;

        rc = ipc_alloc_security(current, &msq->q_perm, SECCLASS_MSGQ);
        if (rc)
                return rc;

        isec = msq->q_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = msq->q_perm.key;

        rc = avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
                          MSGQ__CREATE, &ad);
        if (rc) {
                ipc_free_security(&msq->q_perm);
                return rc;
        }
        return 0;
}

static void selinux_msg_queue_free_security(struct msg_queue *msq)
{
        ipc_free_security(&msq->q_perm);
}

static int selinux_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();

        isec = msq->q_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = msq->q_perm.key;

        return avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
                            MSGQ__ASSOCIATE, &ad);
}

static int selinux_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
        int err;
        int perms;

        switch (cmd) {
        case IPC_INFO:
        case MSG_INFO:
                /* No specific object, just general system-wide information. */
                return task_has_system(current, SYSTEM__IPC_INFO);
        case IPC_STAT:
        case MSG_STAT:
                perms = MSGQ__GETATTR | MSGQ__ASSOCIATE;
                break;
        case IPC_SET:
                perms = MSGQ__SETATTR;
                break;
        case IPC_RMID:
                perms = MSGQ__DESTROY;
                break;
        default:
                return 0;
        }

        err = ipc_has_perm(&msq->q_perm, perms);
        return err;
}

static int selinux_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg, int msqflg)
{
        struct ipc_security_struct *isec;
        struct msg_security_struct *msec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        int rc;

        isec = msq->q_perm.security;
        msec = msg->security;

        /*
         * First time through, need to assign label to the message
         */
        if (msec->sid == SECINITSID_UNLABELED) {
                /*
                 * Compute new sid based on current process and
                 * message queue this message will be stored in
                 */
                rc = security_transition_sid(sid, isec->sid, SECCLASS_MSG,
                                             NULL, &msec->sid);
                if (rc)
                        return rc;
        }

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = msq->q_perm.key;

        /* Can this process write to the queue? */
        rc = avc_has_perm(sid, isec->sid, SECCLASS_MSGQ,
                          MSGQ__WRITE, &ad);
        if (!rc)
                /* Can this process send the message */
                rc = avc_has_perm(sid, msec->sid, SECCLASS_MSG,
                                  MSG__SEND, &ad);
        if (!rc)
                /* Can the message be put in the queue? */
                rc = avc_has_perm(msec->sid, isec->sid, SECCLASS_MSGQ,
                                  MSGQ__ENQUEUE, &ad);

        return rc;
}

static int selinux_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
                                    struct task_struct *target,
                                    long type, int mode)
{
        struct ipc_security_struct *isec;
        struct msg_security_struct *msec;
        struct common_audit_data ad;
        u32 sid = task_sid(target);
        int rc;

        isec = msq->q_perm.security;
        msec = msg->security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = msq->q_perm.key;

        rc = avc_has_perm(sid, isec->sid,
                          SECCLASS_MSGQ, MSGQ__READ, &ad);
        if (!rc)
                rc = avc_has_perm(sid, msec->sid,
                                  SECCLASS_MSG, MSG__RECEIVE, &ad);
        return rc;
}

/* Shared Memory security operations */
static int selinux_shm_alloc_security(struct shmid_kernel *shp)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        int rc;

        rc = ipc_alloc_security(current, &shp->shm_perm, SECCLASS_SHM);
        if (rc)
                return rc;

        isec = shp->shm_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = shp->shm_perm.key;

        rc = avc_has_perm(sid, isec->sid, SECCLASS_SHM,
                          SHM__CREATE, &ad);
        if (rc) {
                ipc_free_security(&shp->shm_perm);
                return rc;
        }
        return 0;
}

static void selinux_shm_free_security(struct shmid_kernel *shp)
{
        ipc_free_security(&shp->shm_perm);
}

static int selinux_shm_associate(struct shmid_kernel *shp, int shmflg)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();

        isec = shp->shm_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = shp->shm_perm.key;

        return avc_has_perm(sid, isec->sid, SECCLASS_SHM,
                            SHM__ASSOCIATE, &ad);
}

/* Note, at this point, shp is locked down */
static int selinux_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
        int perms;
        int err;

        switch (cmd) {
        case IPC_INFO:
        case SHM_INFO:
                /* No specific object, just general system-wide information. */
                return task_has_system(current, SYSTEM__IPC_INFO);
        case IPC_STAT:
        case SHM_STAT:
                perms = SHM__GETATTR | SHM__ASSOCIATE;
                break;
        case IPC_SET:
                perms = SHM__SETATTR;
                break;
        case SHM_LOCK:
        case SHM_UNLOCK:
                perms = SHM__LOCK;
                break;
        case IPC_RMID:
                perms = SHM__DESTROY;
                break;
        default:
                return 0;
        }

        err = ipc_has_perm(&shp->shm_perm, perms);
        return err;
}

static int selinux_shm_shmat(struct shmid_kernel *shp,
                             char __user *shmaddr, int shmflg)
{
        u32 perms;

        if (shmflg & SHM_RDONLY)
                perms = SHM__READ;
        else
                perms = SHM__READ | SHM__WRITE;

        return ipc_has_perm(&shp->shm_perm, perms);
}

/* Semaphore security operations */
static int selinux_sem_alloc_security(struct sem_array *sma)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();
        int rc;

        rc = ipc_alloc_security(current, &sma->sem_perm, SECCLASS_SEM);
        if (rc)
                return rc;

        isec = sma->sem_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = sma->sem_perm.key;

        rc = avc_has_perm(sid, isec->sid, SECCLASS_SEM,
                          SEM__CREATE, &ad);
        if (rc) {
                ipc_free_security(&sma->sem_perm);
                return rc;
        }
        return 0;
}

static void selinux_sem_free_security(struct sem_array *sma)
{
        ipc_free_security(&sma->sem_perm);
}

static int selinux_sem_associate(struct sem_array *sma, int semflg)
{
        struct ipc_security_struct *isec;
        struct common_audit_data ad;
        u32 sid = current_sid();

        isec = sma->sem_perm.security;

        ad.type = LSM_AUDIT_DATA_IPC;
        ad.u.ipc_id = sma->sem_perm.key;

        return avc_has_perm(sid, isec->sid, SECCLASS_SEM,
                            SEM__ASSOCIATE, &ad);
}

/* Note, at this point, sma is locked down */
static int selinux_sem_semctl(struct sem_array *sma, int cmd)
{
        int err;
        u32 perms;

        switch (cmd) {
        case IPC_INFO:
        case SEM_INFO:
                /* No specific object, just general system-wide information. */
                return task_has_system(current, SYSTEM__IPC_INFO);
        case GETPID:
        case GETNCNT:
        case GETZCNT:
                perms = SEM__GETATTR;
                break;
        case GETVAL:
        case GETALL:
                perms = SEM__READ;
                break;
        case SETVAL:
        case SETALL:
                perms = SEM__WRITE;
                break;
        case IPC_RMID:
                perms = SEM__DESTROY;
                break;
        case IPC_SET:
                perms = SEM__SETATTR;
                break;
        case IPC_STAT:
        case SEM_STAT:
                perms = SEM__GETATTR | SEM__ASSOCIATE;
                break;
        default:
                return 0;
        }

        err = ipc_has_perm(&sma->sem_perm, perms);
        return err;
}

static int selinux_sem_semop(struct sem_array *sma,
                             struct sembuf *sops, unsigned nsops, int alter)
{
        u32 perms;

        if (alter)
                perms = SEM__READ | SEM__WRITE;
        else
                perms = SEM__READ;

        return ipc_has_perm(&sma->sem_perm, perms);
}

static int selinux_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
{
        u32 av = 0;

        av = 0;
        if (flag & S_IRUGO)
                av |= IPC__UNIX_READ;
        if (flag & S_IWUGO)
                av |= IPC__UNIX_WRITE;

        if (av == 0)
                return 0;

        return ipc_has_perm(ipcp, av);
}

static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
{
        struct ipc_security_struct *isec = ipcp->security;
        *secid = isec->sid;
}

static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
{
        if (inode)
                inode_doinit_with_dentry(inode, dentry);
}

static int selinux_getprocattr(struct task_struct *p,
                               char *name, char **value)
{
        const struct task_security_struct *__tsec;
        u32 sid;
        int error;
        unsigned len;

        if (current != p) {
                error = current_has_perm(p, PROCESS__GETATTR);
                if (error)
                        return error;
        }

        rcu_read_lock();
        __tsec = __task_cred(p)->security;

        if (!strcmp(name, "current"))
                sid = __tsec->sid;
        else if (!strcmp(name, "prev"))
                sid = __tsec->osid;
        else if (!strcmp(name, "exec"))
                sid = __tsec->exec_sid;
        else if (!strcmp(name, "fscreate"))
                sid = __tsec->create_sid;
        else if (!strcmp(name, "keycreate"))
                sid = __tsec->keycreate_sid;
        else if (!strcmp(name, "sockcreate"))
                sid = __tsec->sockcreate_sid;
        else
                goto invalid;
        rcu_read_unlock();

        if (!sid)
                return 0;

        error = security_sid_to_context(sid, value, &len);
        if (error)
                return error;
        return len;

invalid:
        rcu_read_unlock();
        return -EINVAL;
}

static int selinux_setprocattr(struct task_struct *p,
                               char *name, void *value, size_t size)
{
        struct task_security_struct *tsec;
        struct task_struct *tracer;
        struct cred *new;
        u32 sid = 0, ptsid;
        int error;
        char *str = value;

        if (current != p) {
                /* SELinux only allows a process to change its own
                   security attributes. */
                return -EACCES;
        }

        /*
         * Basic control over ability to set these attributes at all.
         * current == p, but we'll pass them separately in case the
         * above restriction is ever removed.
         */
        if (!strcmp(name, "exec"))
                error = current_has_perm(p, PROCESS__SETEXEC);
        else if (!strcmp(name, "fscreate"))
                error = current_has_perm(p, PROCESS__SETFSCREATE);
        else if (!strcmp(name, "keycreate"))
                error = current_has_perm(p, PROCESS__SETKEYCREATE);
        else if (!strcmp(name, "sockcreate"))
                error = current_has_perm(p, PROCESS__SETSOCKCREATE);
        else if (!strcmp(name, "current"))
                error = current_has_perm(p, PROCESS__SETCURRENT);
        else
                error = -EINVAL;
        if (error)
                return error;

        /* Obtain a SID for the context, if one was specified. */
        if (size && str[1] && str[1] != '\n') {
                if (str[size-1] == '\n') {
                        str[size-1] = 0;
                        size--;
                }
                error = security_context_to_sid(value, size, &sid, GFP_KERNEL);
                if (error == -EINVAL && !strcmp(name, "fscreate")) {
                        if (!capable(CAP_MAC_ADMIN)) {
                                struct audit_buffer *ab;
                                size_t audit_size;

                                /* We strip a nul only if it is at the end, otherwise the
                                 * context contains a nul and we should audit that */
                                if (str[size - 1] == '\0')
                                        audit_size = size - 1;
                                else
                                        audit_size = size;
                                ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_SELINUX_ERR);
                                audit_log_format(ab, "op=fscreate invalid_context=");
                                audit_log_n_untrustedstring(ab, value, audit_size);
                                audit_log_end(ab);

                                return error;
                        }
                        error = security_context_to_sid_force(value, size,
                                                              &sid);
                }
                if (error)
                        return error;
        }

        new = prepare_creds();
        if (!new)
                return -ENOMEM;

        /* Permission checking based on the specified context is
           performed during the actual operation (execve,
           open/mkdir/...), when we know the full context of the
           operation.  See selinux_bprm_set_creds for the execve
           checks and may_create for the file creation checks. The
           operation will then fail if the context is not permitted. */
        tsec = new->security;
        if (!strcmp(name, "exec")) {
                tsec->exec_sid = sid;
        } else if (!strcmp(name, "fscreate")) {
                tsec->create_sid = sid;
        } else if (!strcmp(name, "keycreate")) {
                error = may_create_key(sid, p);
                if (error)
                        goto abort_change;
                tsec->keycreate_sid = sid;
        } else if (!strcmp(name, "sockcreate")) {
                tsec->sockcreate_sid = sid;
        } else if (!strcmp(name, "current")) {
                error = -EINVAL;
                if (sid == 0)
                        goto abort_change;

                /* Only allow single threaded processes to change context */
                error = -EPERM;
                if (!current_is_single_threaded()) {
                        error = security_bounded_transition(tsec->sid, sid);
                        if (error)
                                goto abort_change;
                }

                /* Check permissions for the transition. */
                error = avc_has_perm(tsec->sid, sid, SECCLASS_PROCESS,
                                     PROCESS__DYNTRANSITION, NULL);
                if (error)
                        goto abort_change;

                /* Check for ptracing, and update the task SID if ok.
                   Otherwise, leave SID unchanged and fail. */
                ptsid = 0;
                rcu_read_lock();
                tracer = ptrace_parent(p);
                if (tracer)
                        ptsid = task_sid(tracer);
                rcu_read_unlock();

                if (tracer) {
                        error = avc_has_perm(ptsid, sid, SECCLASS_PROCESS,
                                             PROCESS__PTRACE, NULL);
                        if (error)
                                goto abort_change;
                }

                tsec->sid = sid;
        } else {
                error = -EINVAL;
                goto abort_change;
        }

        commit_creds(new);
        return size;

abort_change:
        abort_creds(new);
        return error;
}

static int selinux_ismaclabel(const char *name)
{
        return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0);
}

static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
        return security_sid_to_context(secid, secdata, seclen);
}

static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
        return security_context_to_sid(secdata, seclen, secid, GFP_KERNEL);
}

static void selinux_release_secctx(char *secdata, u32 seclen)
{
        kfree(secdata);
}

/*
 *      called with inode->i_mutex locked
 */
static int selinux_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
{
        return selinux_inode_setsecurity(inode, XATTR_SELINUX_SUFFIX, ctx, ctxlen, 0);
}

/*
 *      called with inode->i_mutex locked
 */
static int selinux_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
{
        return __vfs_setxattr_noperm(dentry, XATTR_NAME_SELINUX, ctx, ctxlen, 0);
}

static int selinux_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
{
        int len = 0;
        len = selinux_inode_getsecurity(inode, XATTR_SELINUX_SUFFIX,
                                                ctx, true);
        if (len < 0)
                return len;
        *ctxlen = len;
        return 0;
}
#ifdef CONFIG_KEYS

static int selinux_key_alloc(struct key *k, const struct cred *cred,
                             unsigned long flags)
{
        const struct task_security_struct *tsec;
        struct key_security_struct *ksec;

        ksec = kzalloc(sizeof(struct key_security_struct), GFP_KERNEL);
        if (!ksec)
                return -ENOMEM;

        tsec = cred->security;
        if (tsec->keycreate_sid)
                ksec->sid = tsec->keycreate_sid;
        else
                ksec->sid = tsec->sid;

        k->security = ksec;
        return 0;
}

static void selinux_key_free(struct key *k)
{
        struct key_security_struct *ksec = k->security;

        k->security = NULL;
        kfree(ksec);
}

static int selinux_key_permission(key_ref_t key_ref,
                                  const struct cred *cred,
                                  unsigned perm)
{
        struct key *key;
        struct key_security_struct *ksec;
        u32 sid;

        /* if no specific permissions are requested, we skip the
           permission check. No serious, additional covert channels
           appear to be created. */
        if (perm == 0)
                return 0;

        sid = cred_sid(cred);

        key = key_ref_to_ptr(key_ref);
        ksec = key->security;

        return avc_has_perm(sid, ksec->sid, SECCLASS_KEY, perm, NULL);
}

static int selinux_key_getsecurity(struct key *key, char **_buffer)
{
        struct key_security_struct *ksec = key->security;
        char *context = NULL;
        unsigned len;
        int rc;

        rc = security_sid_to_context(ksec->sid, &context, &len);
        if (!rc)
                rc = len;
        *_buffer = context;
        return rc;
}

#endif

static struct security_operations selinux_ops = {
        .name =                         "selinux",

        .binder_set_context_mgr =       selinux_binder_set_context_mgr,
        .binder_transaction =           selinux_binder_transaction,
        .binder_transfer_binder =       selinux_binder_transfer_binder,
        .binder_transfer_file =         selinux_binder_transfer_file,

        .ptrace_access_check =          selinux_ptrace_access_check,
        .ptrace_traceme =               selinux_ptrace_traceme,
        .capget =                       selinux_capget,
        .capset =                       selinux_capset,
        .capable =                      selinux_capable,
        .quotactl =                     selinux_quotactl,
        .quota_on =                     selinux_quota_on,
        .syslog =                       selinux_syslog,
        .vm_enough_memory =             selinux_vm_enough_memory,

        .netlink_send =                 selinux_netlink_send,

        .bprm_set_creds =               selinux_bprm_set_creds,
        .bprm_committing_creds =        selinux_bprm_committing_creds,
        .bprm_committed_creds =         selinux_bprm_committed_creds,
        .bprm_secureexec =              selinux_bprm_secureexec,

        .sb_alloc_security =            selinux_sb_alloc_security,
        .sb_free_security =             selinux_sb_free_security,
        .sb_copy_data =                 selinux_sb_copy_data,
        .sb_remount =                   selinux_sb_remount,
        .sb_kern_mount =                selinux_sb_kern_mount,
        .sb_show_options =              selinux_sb_show_options,
        .sb_statfs =                    selinux_sb_statfs,
        .sb_mount =                     selinux_mount,
        .sb_umount =                    selinux_umount,
        .sb_set_mnt_opts =              selinux_set_mnt_opts,
        .sb_clone_mnt_opts =            selinux_sb_clone_mnt_opts,
        .sb_parse_opts_str =            selinux_parse_opts_str,

        .dentry_init_security =         selinux_dentry_init_security,

        .inode_alloc_security =         selinux_inode_alloc_security,
        .inode_free_security =          selinux_inode_free_security,
        .inode_init_security =          selinux_inode_init_security,
        .inode_create =                 selinux_inode_create,
        .inode_link =                   selinux_inode_link,
        .inode_unlink =                 selinux_inode_unlink,
        .inode_symlink =                selinux_inode_symlink,
        .inode_mkdir =                  selinux_inode_mkdir,
        .inode_rmdir =                  selinux_inode_rmdir,
        .inode_mknod =                  selinux_inode_mknod,
        .inode_rename =                 selinux_inode_rename,
        .inode_readlink =               selinux_inode_readlink,
        .inode_follow_link =            selinux_inode_follow_link,
        .inode_permission =             selinux_inode_permission,
        .inode_setattr =                selinux_inode_setattr,
        .inode_getattr =                selinux_inode_getattr,
        .inode_setxattr =               selinux_inode_setxattr,
        .inode_post_setxattr =          selinux_inode_post_setxattr,
        .inode_getxattr =               selinux_inode_getxattr,
        .inode_listxattr =              selinux_inode_listxattr,
        .inode_removexattr =            selinux_inode_removexattr,
        .inode_getsecurity =            selinux_inode_getsecurity,
        .inode_setsecurity =            selinux_inode_setsecurity,
        .inode_listsecurity =           selinux_inode_listsecurity,
        .inode_getsecid =               selinux_inode_getsecid,

        .file_permission =              selinux_file_permission,
        .file_alloc_security =          selinux_file_alloc_security,
        .file_free_security =           selinux_file_free_security,
        .file_ioctl =                   selinux_file_ioctl,
        .mmap_file =                    selinux_mmap_file,
        .mmap_addr =                    selinux_mmap_addr,
        .file_mprotect =                selinux_file_mprotect,
        .file_lock =                    selinux_file_lock,
        .file_fcntl =                   selinux_file_fcntl,
        .file_set_fowner =              selinux_file_set_fowner,
        .file_send_sigiotask =          selinux_file_send_sigiotask,
        .file_receive =                 selinux_file_receive,

        .file_open =                    selinux_file_open,

        .task_create =                  selinux_task_create,
        .cred_alloc_blank =             selinux_cred_alloc_blank,
        .cred_free =                    selinux_cred_free,
        .cred_prepare =                 selinux_cred_prepare,
        .cred_transfer =                selinux_cred_transfer,
        .kernel_act_as =                selinux_kernel_act_as,
        .kernel_create_files_as =       selinux_kernel_create_files_as,
        .kernel_module_request =        selinux_kernel_module_request,
        .task_setpgid =                 selinux_task_setpgid,
        .task_getpgid =                 selinux_task_getpgid,
        .task_getsid =                  selinux_task_getsid,
        .task_getsecid =                selinux_task_getsecid,
        .task_setnice =                 selinux_task_setnice,
        .task_setioprio =               selinux_task_setioprio,
        .task_getioprio =               selinux_task_getioprio,
        .task_setrlimit =               selinux_task_setrlimit,
        .task_setscheduler =            selinux_task_setscheduler,
        .task_getscheduler =            selinux_task_getscheduler,
        .task_movememory =              selinux_task_movememory,
        .task_kill =                    selinux_task_kill,
        .task_wait =                    selinux_task_wait,
        .task_to_inode =                selinux_task_to_inode,

        .ipc_permission =               selinux_ipc_permission,
        .ipc_getsecid =                 selinux_ipc_getsecid,

        .msg_msg_alloc_security =       selinux_msg_msg_alloc_security,
        .msg_msg_free_security =        selinux_msg_msg_free_security,

        .msg_queue_alloc_security =     selinux_msg_queue_alloc_security,
        .msg_queue_free_security =      selinux_msg_queue_free_security,
        .msg_queue_associate =          selinux_msg_queue_associate,
        .msg_queue_msgctl =             selinux_msg_queue_msgctl,
        .msg_queue_msgsnd =             selinux_msg_queue_msgsnd,
        .msg_queue_msgrcv =             selinux_msg_queue_msgrcv,

        .shm_alloc_security =           selinux_shm_alloc_security,
        .shm_free_security =            selinux_shm_free_security,
        .shm_associate =                selinux_shm_associate,
        .shm_shmctl =                   selinux_shm_shmctl,
        .shm_shmat =                    selinux_shm_shmat,

        .sem_alloc_security =           selinux_sem_alloc_security,
        .sem_free_security =            selinux_sem_free_security,
        .sem_associate =                selinux_sem_associate,
        .sem_semctl =                   selinux_sem_semctl,
        .sem_semop =                    selinux_sem_semop,

        .d_instantiate =                selinux_d_instantiate,

        .getprocattr =                  selinux_getprocattr,
        .setprocattr =                  selinux_setprocattr,

        .ismaclabel =                   selinux_ismaclabel,
        .secid_to_secctx =              selinux_secid_to_secctx,
        .secctx_to_secid =              selinux_secctx_to_secid,
        .release_secctx =               selinux_release_secctx,
        .inode_notifysecctx =           selinux_inode_notifysecctx,
        .inode_setsecctx =              selinux_inode_setsecctx,
        .inode_getsecctx =              selinux_inode_getsecctx,

        .unix_stream_connect =          selinux_socket_unix_stream_connect,
        .unix_may_send =                selinux_socket_unix_may_send,

        .socket_create =                selinux_socket_create,
        .socket_post_create =           selinux_socket_post_create,
        .socket_bind =                  selinux_socket_bind,
        .socket_connect =               selinux_socket_connect,
        .socket_listen =                selinux_socket_listen,
        .socket_accept =                selinux_socket_accept,
        .socket_sendmsg =               selinux_socket_sendmsg,
        .socket_recvmsg =               selinux_socket_recvmsg,
        .socket_getsockname =           selinux_socket_getsockname,
        .socket_getpeername =           selinux_socket_getpeername,
        .socket_getsockopt =            selinux_socket_getsockopt,
        .socket_setsockopt =            selinux_socket_setsockopt,
        .socket_shutdown =              selinux_socket_shutdown,
        .socket_sock_rcv_skb =          selinux_socket_sock_rcv_skb,
        .socket_getpeersec_stream =     selinux_socket_getpeersec_stream,
        .socket_getpeersec_dgram =      selinux_socket_getpeersec_dgram,
        .sk_alloc_security =            selinux_sk_alloc_security,
        .sk_free_security =             selinux_sk_free_security,
        .sk_clone_security =            selinux_sk_clone_security,
        .sk_getsecid =                  selinux_sk_getsecid,
        .sock_graft =                   selinux_sock_graft,
        .inet_conn_request =            selinux_inet_conn_request,
        .inet_csk_clone =               selinux_inet_csk_clone,
        .inet_conn_established =        selinux_inet_conn_established,
        .secmark_relabel_packet =       selinux_secmark_relabel_packet,
        .secmark_refcount_inc =         selinux_secmark_refcount_inc,
        .secmark_refcount_dec =         selinux_secmark_refcount_dec,
        .req_classify_flow =            selinux_req_classify_flow,
        .tun_dev_alloc_security =       selinux_tun_dev_alloc_security,
        .tun_dev_free_security =        selinux_tun_dev_free_security,
        .tun_dev_create =               selinux_tun_dev_create,
        .tun_dev_attach_queue =         selinux_tun_dev_attach_queue,
        .tun_dev_attach =               selinux_tun_dev_attach,
        .tun_dev_open =                 selinux_tun_dev_open,

#ifdef CONFIG_SECURITY_NETWORK_XFRM
        .xfrm_policy_alloc_security =   selinux_xfrm_policy_alloc,
        .xfrm_policy_clone_security =   selinux_xfrm_policy_clone,
        .xfrm_policy_free_security =    selinux_xfrm_policy_free,
        .xfrm_policy_delete_security =  selinux_xfrm_policy_delete,
        .xfrm_state_alloc =             selinux_xfrm_state_alloc,
        .xfrm_state_alloc_acquire =     selinux_xfrm_state_alloc_acquire,
        .xfrm_state_free_security =     selinux_xfrm_state_free,
        .xfrm_state_delete_security =   selinux_xfrm_state_delete,
        .xfrm_policy_lookup =           selinux_xfrm_policy_lookup,
        .xfrm_state_pol_flow_match =    selinux_xfrm_state_pol_flow_match,
        .xfrm_decode_session =          selinux_xfrm_decode_session,
#endif

#ifdef CONFIG_KEYS
        .key_alloc =                    selinux_key_alloc,
        .key_free =                     selinux_key_free,
        .key_permission =               selinux_key_permission,
        .key_getsecurity =              selinux_key_getsecurity,
#endif

#ifdef CONFIG_AUDIT
        .audit_rule_init =              selinux_audit_rule_init,
        .audit_rule_known =             selinux_audit_rule_known,
        .audit_rule_match =             selinux_audit_rule_match,
        .audit_rule_free =              selinux_audit_rule_free,
#endif
};

static __init int selinux_init(void)
{
        if (!security_module_enable(&selinux_ops)) {
                selinux_enabled = 0;
                return 0;
        }

        if (!selinux_enabled) {
                printk(KERN_INFO "SELinux:  Disabled at boot.\n");
                return 0;
        }

        printk(KERN_INFO "SELinux:  Initializing.\n");

        /* Set the security state for the initial task. */
        cred_init_security();

        default_noexec = !(VM_DATA_DEFAULT_FLAGS & VM_EXEC);

        sel_inode_cache = kmem_cache_create("selinux_inode_security",
                                            sizeof(struct inode_security_struct),
                                            0, SLAB_PANIC, NULL);
        avc_init();

        if (register_security(&selinux_ops))
                panic("SELinux: Unable to register with kernel.\n");

        if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
                panic("SELinux: Unable to register AVC netcache callback\n");

        if (selinux_enforcing)
                printk(KERN_DEBUG "SELinux:  Starting in enforcing mode\n");
        else
                printk(KERN_DEBUG "SELinux:  Starting in permissive mode\n");

        return 0;
}

static void delayed_superblock_init(struct super_block *sb, void *unused)
{
        superblock_doinit(sb, NULL);
}

void selinux_complete_init(void)
{
        printk(KERN_DEBUG "SELinux:  Completing initialization.\n");

        /* Set up any superblocks initialized prior to the policy load. */
        printk(KERN_DEBUG "SELinux:  Setting up existing superblocks.\n");
        iterate_supers(delayed_superblock_init, NULL);
}

/* SELinux requires early initialization in order to label
   all processes and objects when they are created. */
security_initcall(selinux_init);

#if defined(CONFIG_NETFILTER)

static struct nf_hook_ops selinux_nf_ops[] = {
        {
                .hook =         selinux_ipv4_postroute,
                .owner =        THIS_MODULE,
                .pf =           NFPROTO_IPV4,
                .hooknum =      NF_INET_POST_ROUTING,
                .priority =     NF_IP_PRI_SELINUX_LAST,
        },
        {
                .hook =         selinux_ipv4_forward,
                .owner =        THIS_MODULE,
                .pf =           NFPROTO_IPV4,
                .hooknum =      NF_INET_FORWARD,
                .priority =     NF_IP_PRI_SELINUX_FIRST,
        },
        {
                .hook =         selinux_ipv4_output,
                .owner =        THIS_MODULE,
                .pf =           NFPROTO_IPV4,
                .hooknum =      NF_INET_LOCAL_OUT,
                .priority =     NF_IP_PRI_SELINUX_FIRST,
        },
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
        {
                .hook =         selinux_ipv6_postroute,
                .owner =        THIS_MODULE,
                .pf =           NFPROTO_IPV6,
                .hooknum =      NF_INET_POST_ROUTING,
                .priority =     NF_IP6_PRI_SELINUX_LAST,
        },
        {
                .hook =         selinux_ipv6_forward,
                .owner =        THIS_MODULE,
                .pf =           NFPROTO_IPV6,
                .hooknum =      NF_INET_FORWARD,
                .priority =     NF_IP6_PRI_SELINUX_FIRST,
        },
#endif  /* IPV6 */
};

static int __init selinux_nf_ip_init(void)
{
        int err;

        if (!selinux_enabled)
                return 0;

        printk(KERN_DEBUG "SELinux:  Registering netfilter hooks\n");

        err = nf_register_hooks(selinux_nf_ops, ARRAY_SIZE(selinux_nf_ops));
        if (err)
                panic("SELinux: nf_register_hooks: error %d\n", err);

        return 0;
}

__initcall(selinux_nf_ip_init);

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static void selinux_nf_ip_exit(void)
{
        printk(KERN_DEBUG "SELinux:  Unregistering netfilter hooks\n");

        nf_unregister_hooks(selinux_nf_ops, ARRAY_SIZE(selinux_nf_ops));
}
#endif

#else /* CONFIG_NETFILTER */

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
#define selinux_nf_ip_exit()
#endif

#endif /* CONFIG_NETFILTER */

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static int selinux_disabled;

int selinux_disable(void)
{
        if (ss_initialized) {
                /* Not permitted after initial policy load. */
                return -EINVAL;
        }

        if (selinux_disabled) {
                /* Only do this once. */
                return -EINVAL;
        }

        printk(KERN_INFO "SELinux:  Disabled at runtime.\n");

        selinux_disabled = 1;
        selinux_enabled = 0;

        reset_security_ops();

        /* Try to destroy the avc node cache */
        avc_disable();

        /* Unregister netfilter hooks. */
        selinux_nf_ip_exit();

        /* Unregister selinuxfs. */
        exit_sel_fs();

        return 0;
}
#endif