sched/headers: Prepare for new header dependencies before moving code to <linux/sched...

[mirror_ubuntu-bionic-kernel.git] / security / selinux / selinuxfs.c

/* Updated: Karl MacMillan <kmacmillan@tresys.com>
 *
 *      Added conditional policy language extensions
 *
 *  Updated: Hewlett-Packard <paul@paul-moore.com>
 *
 *      Added support for the policy capability bitmap
 *
 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
 * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation, version 2.
 */

#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/security.h>
#include <linux/major.h>
#include <linux/seq_file.h>
#include <linux/percpu.h>
#include <linux/audit.h>
#include <linux/uaccess.h>
#include <linux/kobject.h>
#include <linux/ctype.h>

/* selinuxfs pseudo filesystem for exporting the security policy API.
   Based on the proc code and the fs/nfsd/nfsctl.c code. */

#include "flask.h"
#include "avc.h"
#include "avc_ss.h"
#include "security.h"
#include "objsec.h"
#include "conditional.h"

/* Policy capability filenames */
static char *policycap_names[] = {
        "network_peer_controls",
        "open_perms",
        "extended_socket_class",
        "always_check_network"
};

unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;

static int __init checkreqprot_setup(char *str)
{
        unsigned long checkreqprot;
        if (!kstrtoul(str, 0, &checkreqprot))
                selinux_checkreqprot = checkreqprot ? 1 : 0;
        return 1;
}
__setup("checkreqprot=", checkreqprot_setup);

static DEFINE_MUTEX(sel_mutex);

/* global data for booleans */
static struct dentry *bool_dir;
static int bool_num;
static char **bool_pending_names;
static int *bool_pending_values;

/* global data for classes */
static struct dentry *class_dir;
static unsigned long last_class_ino;

static char policy_opened;

/* global data for policy capabilities */
static struct dentry *policycap_dir;

enum sel_inos {
        SEL_ROOT_INO = 2,
        SEL_LOAD,       /* load policy */
        SEL_ENFORCE,    /* get or set enforcing status */
        SEL_CONTEXT,    /* validate context */
        SEL_ACCESS,     /* compute access decision */
        SEL_CREATE,     /* compute create labeling decision */
        SEL_RELABEL,    /* compute relabeling decision */
        SEL_USER,       /* compute reachable user contexts */
        SEL_POLICYVERS, /* return policy version for this kernel */
        SEL_COMMIT_BOOLS, /* commit new boolean values */
        SEL_MLS,        /* return if MLS policy is enabled */
        SEL_DISABLE,    /* disable SELinux until next reboot */
        SEL_MEMBER,     /* compute polyinstantiation membership decision */
        SEL_CHECKREQPROT, /* check requested protection, not kernel-applied one */
        SEL_COMPAT_NET, /* whether to use old compat network packet controls */
        SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */
        SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */
        SEL_STATUS,     /* export current status using mmap() */
        SEL_POLICY,     /* allow userspace to read the in kernel policy */
        SEL_VALIDATE_TRANS, /* compute validatetrans decision */
        SEL_INO_NEXT,   /* The next inode number to use */
};

static unsigned long sel_last_ino = SEL_INO_NEXT - 1;

#define SEL_INITCON_INO_OFFSET          0x01000000
#define SEL_BOOL_INO_OFFSET             0x02000000
#define SEL_CLASS_INO_OFFSET            0x04000000
#define SEL_POLICYCAP_INO_OFFSET        0x08000000
#define SEL_INO_MASK                    0x00ffffff

#define TMPBUFLEN       12
static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;

        length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_enforcing);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)

{
        char *page = NULL;
        ssize_t length;
        int new_value;

        if (count >= PAGE_SIZE)
                return -ENOMEM;

        /* No partial writes. */
        if (*ppos != 0)
                return -EINVAL;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page))
                return PTR_ERR(page);

        length = -EINVAL;
        if (sscanf(page, "%d", &new_value) != 1)
                goto out;

        new_value = !!new_value;

        if (new_value != selinux_enforcing) {
                length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                                      SECCLASS_SECURITY, SECURITY__SETENFORCE,
                                      NULL);
                if (length)
                        goto out;
                audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
                        "enforcing=%d old_enforcing=%d auid=%u ses=%u",
                        new_value, selinux_enforcing,
                        from_kuid(&init_user_ns, audit_get_loginuid(current)),
                        audit_get_sessionid(current));
                selinux_enforcing = new_value;
                if (selinux_enforcing)
                        avc_ss_reset(0);
                selnl_notify_setenforce(selinux_enforcing);
                selinux_status_update_setenforce(selinux_enforcing);
        }
        length = count;
out:
        kfree(page);
        return length;
}
#else
#define sel_write_enforce NULL
#endif

static const struct file_operations sel_enforce_ops = {
        .read           = sel_read_enforce,
        .write          = sel_write_enforce,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_read_handle_unknown(struct file *filp, char __user *buf,
                                        size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;
        ino_t ino = file_inode(filp)->i_ino;
        int handle_unknown = (ino == SEL_REJECT_UNKNOWN) ?
                security_get_reject_unknown() : !security_get_allow_unknown();

        length = scnprintf(tmpbuf, TMPBUFLEN, "%d", handle_unknown);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static const struct file_operations sel_handle_unknown_ops = {
        .read           = sel_read_handle_unknown,
        .llseek         = generic_file_llseek,
};

static int sel_open_handle_status(struct inode *inode, struct file *filp)
{
        struct page    *status = selinux_kernel_status_page();

        if (!status)
                return -ENOMEM;

        filp->private_data = status;

        return 0;
}

static ssize_t sel_read_handle_status(struct file *filp, char __user *buf,
                                      size_t count, loff_t *ppos)
{
        struct page    *status = filp->private_data;

        BUG_ON(!status);

        return simple_read_from_buffer(buf, count, ppos,
                                       page_address(status),
                                       sizeof(struct selinux_kernel_status));
}

static int sel_mmap_handle_status(struct file *filp,
                                  struct vm_area_struct *vma)
{
        struct page    *status = filp->private_data;
        unsigned long   size = vma->vm_end - vma->vm_start;

        BUG_ON(!status);

        /* only allows one page from the head */
        if (vma->vm_pgoff > 0 || size != PAGE_SIZE)
                return -EIO;
        /* disallow writable mapping */
        if (vma->vm_flags & VM_WRITE)
                return -EPERM;
        /* disallow mprotect() turns it into writable */
        vma->vm_flags &= ~VM_MAYWRITE;

        return remap_pfn_range(vma, vma->vm_start,
                               page_to_pfn(status),
                               size, vma->vm_page_prot);
}

static const struct file_operations sel_handle_status_ops = {
        .open           = sel_open_handle_status,
        .read           = sel_read_handle_status,
        .mmap           = sel_mmap_handle_status,
        .llseek         = generic_file_llseek,
};

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
static ssize_t sel_write_disable(struct file *file, const char __user *buf,
                                 size_t count, loff_t *ppos)

{
        char *page;
        ssize_t length;
        int new_value;

        if (count >= PAGE_SIZE)
                return -ENOMEM;

        /* No partial writes. */
        if (*ppos != 0)
                return -EINVAL;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page))
                return PTR_ERR(page);

        length = -EINVAL;
        if (sscanf(page, "%d", &new_value) != 1)
                goto out;

        if (new_value) {
                length = selinux_disable();
                if (length)
                        goto out;
                audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
                        "selinux=0 auid=%u ses=%u",
                        from_kuid(&init_user_ns, audit_get_loginuid(current)),
                        audit_get_sessionid(current));
        }

        length = count;
out:
        kfree(page);
        return length;
}
#else
#define sel_write_disable NULL
#endif

static const struct file_operations sel_disable_ops = {
        .write          = sel_write_disable,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_read_policyvers(struct file *filp, char __user *buf,
                                   size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;

        length = scnprintf(tmpbuf, TMPBUFLEN, "%u", POLICYDB_VERSION_MAX);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static const struct file_operations sel_policyvers_ops = {
        .read           = sel_read_policyvers,
        .llseek         = generic_file_llseek,
};

/* declaration for sel_write_load */
static int sel_make_bools(void);
static int sel_make_classes(void);
static int sel_make_policycap(void);

/* declaration for sel_make_class_dirs */
static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
                        unsigned long *ino);

static ssize_t sel_read_mls(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;

        length = scnprintf(tmpbuf, TMPBUFLEN, "%d",
                           security_mls_enabled());
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static const struct file_operations sel_mls_ops = {
        .read           = sel_read_mls,
        .llseek         = generic_file_llseek,
};

struct policy_load_memory {
        size_t len;
        void *data;
};

static int sel_open_policy(struct inode *inode, struct file *filp)
{
        struct policy_load_memory *plm = NULL;
        int rc;

        BUG_ON(filp->private_data);

        mutex_lock(&sel_mutex);

        rc = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                          SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL);
        if (rc)
                goto err;

        rc = -EBUSY;
        if (policy_opened)
                goto err;

        rc = -ENOMEM;
        plm = kzalloc(sizeof(*plm), GFP_KERNEL);
        if (!plm)
                goto err;

        if (i_size_read(inode) != security_policydb_len()) {
                inode_lock(inode);
                i_size_write(inode, security_policydb_len());
                inode_unlock(inode);
        }

        rc = security_read_policy(&plm->data, &plm->len);
        if (rc)
                goto err;

        policy_opened = 1;

        filp->private_data = plm;

        mutex_unlock(&sel_mutex);

        return 0;
err:
        mutex_unlock(&sel_mutex);

        if (plm)
                vfree(plm->data);
        kfree(plm);
        return rc;
}

static int sel_release_policy(struct inode *inode, struct file *filp)
{
        struct policy_load_memory *plm = filp->private_data;

        BUG_ON(!plm);

        policy_opened = 0;

        vfree(plm->data);
        kfree(plm);

        return 0;
}

static ssize_t sel_read_policy(struct file *filp, char __user *buf,
                               size_t count, loff_t *ppos)
{
        struct policy_load_memory *plm = filp->private_data;
        int ret;

        mutex_lock(&sel_mutex);

        ret = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                          SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL);
        if (ret)
                goto out;

        ret = simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
out:
        mutex_unlock(&sel_mutex);
        return ret;
}

static int sel_mmap_policy_fault(struct vm_fault *vmf)
{
        struct policy_load_memory *plm = vmf->vma->vm_file->private_data;
        unsigned long offset;
        struct page *page;

        if (vmf->flags & (FAULT_FLAG_MKWRITE | FAULT_FLAG_WRITE))
                return VM_FAULT_SIGBUS;

        offset = vmf->pgoff << PAGE_SHIFT;
        if (offset >= roundup(plm->len, PAGE_SIZE))
                return VM_FAULT_SIGBUS;

        page = vmalloc_to_page(plm->data + offset);
        get_page(page);

        vmf->page = page;

        return 0;
}

static const struct vm_operations_struct sel_mmap_policy_ops = {
        .fault = sel_mmap_policy_fault,
        .page_mkwrite = sel_mmap_policy_fault,
};

static int sel_mmap_policy(struct file *filp, struct vm_area_struct *vma)
{
        if (vma->vm_flags & VM_SHARED) {
                /* do not allow mprotect to make mapping writable */
                vma->vm_flags &= ~VM_MAYWRITE;

                if (vma->vm_flags & VM_WRITE)
                        return -EACCES;
        }

        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
        vma->vm_ops = &sel_mmap_policy_ops;

        return 0;
}

static const struct file_operations sel_policy_ops = {
        .open           = sel_open_policy,
        .read           = sel_read_policy,
        .mmap           = sel_mmap_policy,
        .release        = sel_release_policy,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_write_load(struct file *file, const char __user *buf,
                              size_t count, loff_t *ppos)

{
        ssize_t length;
        void *data = NULL;

        mutex_lock(&sel_mutex);

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__LOAD_POLICY, NULL);
        if (length)
                goto out;

        /* No partial writes. */
        length = -EINVAL;
        if (*ppos != 0)
                goto out;

        length = -EFBIG;
        if (count > 64 * 1024 * 1024)
                goto out;

        length = -ENOMEM;
        data = vmalloc(count);
        if (!data)
                goto out;

        length = -EFAULT;
        if (copy_from_user(data, buf, count) != 0)
                goto out;

        length = security_load_policy(data, count);
        if (length) {
                pr_warn_ratelimited("SELinux: failed to load policy\n");
                goto out;
        }

        length = sel_make_bools();
        if (length) {
                pr_err("SELinux: failed to load policy booleans\n");
                goto out1;
        }

        length = sel_make_classes();
        if (length) {
                pr_err("SELinux: failed to load policy classes\n");
                goto out1;
        }

        length = sel_make_policycap();
        if (length) {
                pr_err("SELinux: failed to load policy capabilities\n");
                goto out1;
        }

        length = count;

out1:
        audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
                "policy loaded auid=%u ses=%u",
                from_kuid(&init_user_ns, audit_get_loginuid(current)),
                audit_get_sessionid(current));
out:
        mutex_unlock(&sel_mutex);
        vfree(data);
        return length;
}

static const struct file_operations sel_load_ops = {
        .write          = sel_write_load,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
{
        char *canon = NULL;
        u32 sid, len;
        ssize_t length;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__CHECK_CONTEXT, NULL);
        if (length)
                goto out;

        length = security_context_to_sid(buf, size, &sid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_sid_to_context(sid, &canon, &len);
        if (length)
                goto out;

        length = -ERANGE;
        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
                        "payload max\n", __func__, len);
                goto out;
        }

        memcpy(buf, canon, len);
        length = len;
out:
        kfree(canon);
        return length;
}

static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf,
                                     size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;

        length = scnprintf(tmpbuf, TMPBUFLEN, "%u", selinux_checkreqprot);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
                                      size_t count, loff_t *ppos)
{
        char *page;
        ssize_t length;
        unsigned int new_value;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__SETCHECKREQPROT,
                              NULL);
        if (length)
                return length;

        if (count >= PAGE_SIZE)
                return -ENOMEM;

        /* No partial writes. */
        if (*ppos != 0)
                return -EINVAL;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page))
                return PTR_ERR(page);

        length = -EINVAL;
        if (sscanf(page, "%u", &new_value) != 1)
                goto out;

        selinux_checkreqprot = new_value ? 1 : 0;
        length = count;
out:
        kfree(page);
        return length;
}
static const struct file_operations sel_checkreqprot_ops = {
        .read           = sel_read_checkreqprot,
        .write          = sel_write_checkreqprot,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_write_validatetrans(struct file *file,
                                        const char __user *buf,
                                        size_t count, loff_t *ppos)
{
        char *oldcon = NULL, *newcon = NULL, *taskcon = NULL;
        char *req = NULL;
        u32 osid, nsid, tsid;
        u16 tclass;
        int rc;

        rc = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                          SECCLASS_SECURITY, SECURITY__VALIDATE_TRANS, NULL);
        if (rc)
                goto out;

        rc = -ENOMEM;
        if (count >= PAGE_SIZE)
                goto out;

        /* No partial writes. */
        rc = -EINVAL;
        if (*ppos != 0)
                goto out;

        rc = -ENOMEM;
        req = kzalloc(count + 1, GFP_KERNEL);
        if (!req)
                goto out;

        rc = -EFAULT;
        if (copy_from_user(req, buf, count))
                goto out;

        rc = -ENOMEM;
        oldcon = kzalloc(count + 1, GFP_KERNEL);
        if (!oldcon)
                goto out;

        newcon = kzalloc(count + 1, GFP_KERNEL);
        if (!newcon)
                goto out;

        taskcon = kzalloc(count + 1, GFP_KERNEL);
        if (!taskcon)
                goto out;

        rc = -EINVAL;
        if (sscanf(req, "%s %s %hu %s", oldcon, newcon, &tclass, taskcon) != 4)
                goto out;

        rc = security_context_str_to_sid(oldcon, &osid, GFP_KERNEL);
        if (rc)
                goto out;

        rc = security_context_str_to_sid(newcon, &nsid, GFP_KERNEL);
        if (rc)
                goto out;

        rc = security_context_str_to_sid(taskcon, &tsid, GFP_KERNEL);
        if (rc)
                goto out;

        rc = security_validate_transition_user(osid, nsid, tsid, tclass);
        if (!rc)
                rc = count;
out:
        kfree(req);
        kfree(oldcon);
        kfree(newcon);
        kfree(taskcon);
        return rc;
}

static const struct file_operations sel_transition_ops = {
        .write          = sel_write_validatetrans,
        .llseek         = generic_file_llseek,
};

/*
 * Remaining nodes use transaction based IO methods like nfsd/nfsctl.c
 */
static ssize_t sel_write_access(struct file *file, char *buf, size_t size);
static ssize_t sel_write_create(struct file *file, char *buf, size_t size);
static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size);
static ssize_t sel_write_user(struct file *file, char *buf, size_t size);
static ssize_t sel_write_member(struct file *file, char *buf, size_t size);

static ssize_t (*write_op[])(struct file *, char *, size_t) = {
        [SEL_ACCESS] = sel_write_access,
        [SEL_CREATE] = sel_write_create,
        [SEL_RELABEL] = sel_write_relabel,
        [SEL_USER] = sel_write_user,
        [SEL_MEMBER] = sel_write_member,
        [SEL_CONTEXT] = sel_write_context,
};

static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
{
        ino_t ino = file_inode(file)->i_ino;
        char *data;
        ssize_t rv;

        if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
                return -EINVAL;

        data = simple_transaction_get(file, buf, size);
        if (IS_ERR(data))
                return PTR_ERR(data);

        rv = write_op[ino](file, data, size);
        if (rv > 0) {
                simple_transaction_set(file, rv);
                rv = size;
        }
        return rv;
}

static const struct file_operations transaction_ops = {
        .write          = selinux_transaction_write,
        .read           = simple_transaction_read,
        .release        = simple_transaction_release,
        .llseek         = generic_file_llseek,
};

/*
 * payload - write methods
 * If the method has a response, the response should be put in buf,
 * and the length returned.  Otherwise return 0 or and -error.
 */

static ssize_t sel_write_access(struct file *file, char *buf, size_t size)
{
        char *scon = NULL, *tcon = NULL;
        u32 ssid, tsid;
        u16 tclass;
        struct av_decision avd;
        ssize_t length;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__COMPUTE_AV, NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        scon = kzalloc(size + 1, GFP_KERNEL);
        if (!scon)
                goto out;

        length = -ENOMEM;
        tcon = kzalloc(size + 1, GFP_KERNEL);
        if (!tcon)
                goto out;

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out;

        length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
        if (length)
                goto out;

        security_compute_av_user(ssid, tsid, tclass, &avd);

        length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
                          "%x %x %x %x %u %x",
                          avd.allowed, 0xffffffff,
                          avd.auditallow, avd.auditdeny,
                          avd.seqno, avd.flags);
out:
        kfree(tcon);
        kfree(scon);
        return length;
}

static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
{
        char *scon = NULL, *tcon = NULL;
        char *namebuf = NULL, *objname = NULL;
        u32 ssid, tsid, newsid;
        u16 tclass;
        ssize_t length;
        char *newcon = NULL;
        u32 len;
        int nargs;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__COMPUTE_CREATE,
                              NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        scon = kzalloc(size + 1, GFP_KERNEL);
        if (!scon)
                goto out;

        length = -ENOMEM;
        tcon = kzalloc(size + 1, GFP_KERNEL);
        if (!tcon)
                goto out;

        length = -ENOMEM;
        namebuf = kzalloc(size + 1, GFP_KERNEL);
        if (!namebuf)
                goto out;

        length = -EINVAL;
        nargs = sscanf(buf, "%s %s %hu %s", scon, tcon, &tclass, namebuf);
        if (nargs < 3 || nargs > 4)
                goto out;
        if (nargs == 4) {
                /*
                 * If and when the name of new object to be queried contains
                 * either whitespace or multibyte characters, they shall be
                 * encoded based on the percentage-encoding rule.
                 * If not encoded, the sscanf logic picks up only left-half
                 * of the supplied name; splitted by a whitespace unexpectedly.
                 */
                char   *r, *w;
                int     c1, c2;

                r = w = namebuf;
                do {
                        c1 = *r++;
                        if (c1 == '+')
                                c1 = ' ';
                        else if (c1 == '%') {
                                c1 = hex_to_bin(*r++);
                                if (c1 < 0)
                                        goto out;
                                c2 = hex_to_bin(*r++);
                                if (c2 < 0)
                                        goto out;
                                c1 = (c1 << 4) | c2;
                        }
                        *w++ = c1;
                } while (c1 != '\0');

                objname = namebuf;
        }

        length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_transition_sid_user(ssid, tsid, tclass,
                                              objname, &newsid);
        if (length)
                goto out;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length)
                goto out;

        length = -ERANGE;
        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
                        "payload max\n", __func__, len);
                goto out;
        }

        memcpy(buf, newcon, len);
        length = len;
out:
        kfree(newcon);
        kfree(namebuf);
        kfree(tcon);
        kfree(scon);
        return length;
}

static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
{
        char *scon = NULL, *tcon = NULL;
        u32 ssid, tsid, newsid;
        u16 tclass;
        ssize_t length;
        char *newcon = NULL;
        u32 len;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__COMPUTE_RELABEL,
                              NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        scon = kzalloc(size + 1, GFP_KERNEL);
        if (!scon)
                goto out;

        length = -ENOMEM;
        tcon = kzalloc(size + 1, GFP_KERNEL);
        if (!tcon)
                goto out;

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out;

        length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_change_sid(ssid, tsid, tclass, &newsid);
        if (length)
                goto out;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length)
                goto out;

        length = -ERANGE;
        if (len > SIMPLE_TRANSACTION_LIMIT)
                goto out;

        memcpy(buf, newcon, len);
        length = len;
out:
        kfree(newcon);
        kfree(tcon);
        kfree(scon);
        return length;
}

static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
{
        char *con = NULL, *user = NULL, *ptr;
        u32 sid, *sids = NULL;
        ssize_t length;
        char *newcon;
        int i, rc;
        u32 len, nsids;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__COMPUTE_USER,
                              NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        con = kzalloc(size + 1, GFP_KERNEL);
        if (!con)
                goto out;

        length = -ENOMEM;
        user = kzalloc(size + 1, GFP_KERNEL);
        if (!user)
                goto out;

        length = -EINVAL;
        if (sscanf(buf, "%s %s", con, user) != 2)
                goto out;

        length = security_context_str_to_sid(con, &sid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_get_user_sids(sid, user, &sids, &nsids);
        if (length)
                goto out;

        length = sprintf(buf, "%u", nsids) + 1;
        ptr = buf + length;
        for (i = 0; i < nsids; i++) {
                rc = security_sid_to_context(sids[i], &newcon, &len);
                if (rc) {
                        length = rc;
                        goto out;
                }
                if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
                        kfree(newcon);
                        length = -ERANGE;
                        goto out;
                }
                memcpy(ptr, newcon, len);
                kfree(newcon);
                ptr += len;
                length += len;
        }
out:
        kfree(sids);
        kfree(user);
        kfree(con);
        return length;
}

static ssize_t sel_write_member(struct file *file, char *buf, size_t size)
{
        char *scon = NULL, *tcon = NULL;
        u32 ssid, tsid, newsid;
        u16 tclass;
        ssize_t length;
        char *newcon = NULL;
        u32 len;

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__COMPUTE_MEMBER,
                              NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        scon = kzalloc(size + 1, GFP_KERNEL);
        if (!scon)
                goto out;

        length = -ENOMEM;
        tcon = kzalloc(size + 1, GFP_KERNEL);
        if (!tcon)
                goto out;

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out;

        length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
        if (length)
                goto out;

        length = security_member_sid(ssid, tsid, tclass, &newsid);
        if (length)
                goto out;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length)
                goto out;

        length = -ERANGE;
        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
                        "payload max\n", __func__, len);
                goto out;
        }

        memcpy(buf, newcon, len);
        length = len;
out:
        kfree(newcon);
        kfree(tcon);
        kfree(scon);
        return length;
}

static struct inode *sel_make_inode(struct super_block *sb, int mode)
{
        struct inode *ret = new_inode(sb);

        if (ret) {
                ret->i_mode = mode;
                ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
        }
        return ret;
}

static ssize_t sel_read_bool(struct file *filep, char __user *buf,
                             size_t count, loff_t *ppos)
{
        char *page = NULL;
        ssize_t length;
        ssize_t ret;
        int cur_enforcing;
        unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
        const char *name = filep->f_path.dentry->d_name.name;

        mutex_lock(&sel_mutex);

        ret = -EINVAL;
        if (index >= bool_num || strcmp(name, bool_pending_names[index]))
                goto out;

        ret = -ENOMEM;
        page = (char *)get_zeroed_page(GFP_KERNEL);
        if (!page)
                goto out;

        cur_enforcing = security_get_bool_value(index);
        if (cur_enforcing < 0) {
                ret = cur_enforcing;
                goto out;
        }
        length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
                          bool_pending_values[index]);
        ret = simple_read_from_buffer(buf, count, ppos, page, length);
out:
        mutex_unlock(&sel_mutex);
        free_page((unsigned long)page);
        return ret;
}

static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
                              size_t count, loff_t *ppos)
{
        char *page = NULL;
        ssize_t length;
        int new_value;
        unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
        const char *name = filep->f_path.dentry->d_name.name;

        mutex_lock(&sel_mutex);

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__SETBOOL,
                              NULL);
        if (length)
                goto out;

        length = -EINVAL;
        if (index >= bool_num || strcmp(name, bool_pending_names[index]))
                goto out;

        length = -ENOMEM;
        if (count >= PAGE_SIZE)
                goto out;

        /* No partial writes. */
        length = -EINVAL;
        if (*ppos != 0)
                goto out;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page)) {
                length = PTR_ERR(page);
                page = NULL;
                goto out;
        }

        length = -EINVAL;
        if (sscanf(page, "%d", &new_value) != 1)
                goto out;

        if (new_value)
                new_value = 1;

        bool_pending_values[index] = new_value;
        length = count;

out:
        mutex_unlock(&sel_mutex);
        kfree(page);
        return length;
}

static const struct file_operations sel_bool_ops = {
        .read           = sel_read_bool,
        .write          = sel_write_bool,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_commit_bools_write(struct file *filep,
                                      const char __user *buf,
                                      size_t count, loff_t *ppos)
{
        char *page = NULL;
        ssize_t length;
        int new_value;

        mutex_lock(&sel_mutex);

        length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                              SECCLASS_SECURITY, SECURITY__SETBOOL,
                              NULL);
        if (length)
                goto out;

        length = -ENOMEM;
        if (count >= PAGE_SIZE)
                goto out;

        /* No partial writes. */
        length = -EINVAL;
        if (*ppos != 0)
                goto out;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page)) {
                length = PTR_ERR(page);
                page = NULL;
                goto out;
        }

        length = -EINVAL;
        if (sscanf(page, "%d", &new_value) != 1)
                goto out;

        length = 0;
        if (new_value && bool_pending_values)
                length = security_set_bools(bool_num, bool_pending_values);

        if (!length)
                length = count;

out:
        mutex_unlock(&sel_mutex);
        kfree(page);
        return length;
}

static const struct file_operations sel_commit_bools_ops = {
        .write          = sel_commit_bools_write,
        .llseek         = generic_file_llseek,
};

static void sel_remove_entries(struct dentry *de)
{
        d_genocide(de);
        shrink_dcache_parent(de);
}

#define BOOL_DIR_NAME "booleans"

static int sel_make_bools(void)
{
        int i, ret;
        ssize_t len;
        struct dentry *dentry = NULL;
        struct dentry *dir = bool_dir;
        struct inode *inode = NULL;
        struct inode_security_struct *isec;
        char **names = NULL, *page;
        int num;
        int *values = NULL;
        u32 sid;

        /* remove any existing files */
        for (i = 0; i < bool_num; i++)
                kfree(bool_pending_names[i]);
        kfree(bool_pending_names);
        kfree(bool_pending_values);
        bool_num = 0;
        bool_pending_names = NULL;
        bool_pending_values = NULL;

        sel_remove_entries(dir);

        ret = -ENOMEM;
        page = (char *)get_zeroed_page(GFP_KERNEL);
        if (!page)
                goto out;

        ret = security_get_bools(&num, &names, &values);
        if (ret)
                goto out;

        for (i = 0; i < num; i++) {
                ret = -ENOMEM;
                dentry = d_alloc_name(dir, names[i]);
                if (!dentry)
                        goto out;

                ret = -ENOMEM;
                inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
                if (!inode)
                        goto out;

                ret = -ENAMETOOLONG;
                len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
                if (len >= PAGE_SIZE)
                        goto out;

                isec = (struct inode_security_struct *)inode->i_security;
                ret = security_genfs_sid("selinuxfs", page, SECCLASS_FILE, &sid);
                if (ret) {
                        pr_warn_ratelimited("SELinux: no sid found, defaulting to security isid for %s\n",
                                           page);
                        sid = SECINITSID_SECURITY;
                }

                isec->sid = sid;
                isec->initialized = LABEL_INITIALIZED;
                inode->i_fop = &sel_bool_ops;
                inode->i_ino = i|SEL_BOOL_INO_OFFSET;
                d_add(dentry, inode);
        }
        bool_num = num;
        bool_pending_names = names;
        bool_pending_values = values;

        free_page((unsigned long)page);
        return 0;
out:
        free_page((unsigned long)page);

        if (names) {
                for (i = 0; i < num; i++)
                        kfree(names[i]);
                kfree(names);
        }
        kfree(values);
        sel_remove_entries(dir);

        return ret;
}

#define NULL_FILE_NAME "null"

struct path selinux_null;

static ssize_t sel_read_avc_cache_threshold(struct file *filp, char __user *buf,
                                            size_t count, loff_t *ppos)
{
        char tmpbuf[TMPBUFLEN];
        ssize_t length;

        length = scnprintf(tmpbuf, TMPBUFLEN, "%u", avc_cache_threshold);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static ssize_t sel_write_avc_cache_threshold(struct file *file,
                                             const char __user *buf,
                                             size_t count, loff_t *ppos)

{
        char *page;
        ssize_t ret;
        unsigned int new_value;

        ret = avc_has_perm(current_sid(), SECINITSID_SECURITY,
                           SECCLASS_SECURITY, SECURITY__SETSECPARAM,
                           NULL);
        if (ret)
                return ret;

        if (count >= PAGE_SIZE)
                return -ENOMEM;

        /* No partial writes. */
        if (*ppos != 0)
                return -EINVAL;

        page = memdup_user_nul(buf, count);
        if (IS_ERR(page))
                return PTR_ERR(page);

        ret = -EINVAL;
        if (sscanf(page, "%u", &new_value) != 1)
                goto out;

        avc_cache_threshold = new_value;

        ret = count;
out:
        kfree(page);
        return ret;
}

static ssize_t sel_read_avc_hash_stats(struct file *filp, char __user *buf,
                                       size_t count, loff_t *ppos)
{
        char *page;
        ssize_t length;

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

        length = avc_get_hash_stats(page);
        if (length >= 0)
                length = simple_read_from_buffer(buf, count, ppos, page, length);
        free_page((unsigned long)page);

        return length;
}

static const struct file_operations sel_avc_cache_threshold_ops = {
        .read           = sel_read_avc_cache_threshold,
        .write          = sel_write_avc_cache_threshold,
        .llseek         = generic_file_llseek,
};

static const struct file_operations sel_avc_hash_stats_ops = {
        .read           = sel_read_avc_hash_stats,
        .llseek         = generic_file_llseek,
};

#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
{
        int cpu;

        for (cpu = *idx; cpu < nr_cpu_ids; ++cpu) {
                if (!cpu_possible(cpu))
                        continue;
                *idx = cpu + 1;
                return &per_cpu(avc_cache_stats, cpu);
        }
        return NULL;
}

static void *sel_avc_stats_seq_start(struct seq_file *seq, loff_t *pos)
{
        loff_t n = *pos - 1;

        if (*pos == 0)
                return SEQ_START_TOKEN;

        return sel_avc_get_stat_idx(&n);
}

static void *sel_avc_stats_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        return sel_avc_get_stat_idx(pos);
}

static int sel_avc_stats_seq_show(struct seq_file *seq, void *v)
{
        struct avc_cache_stats *st = v;

        if (v == SEQ_START_TOKEN)
                seq_printf(seq, "lookups hits misses allocations reclaims "
                           "frees\n");
        else {
                unsigned int lookups = st->lookups;
                unsigned int misses = st->misses;
                unsigned int hits = lookups - misses;
                seq_printf(seq, "%u %u %u %u %u %u\n", lookups,
                           hits, misses, st->allocations,
                           st->reclaims, st->frees);
        }
        return 0;
}

static void sel_avc_stats_seq_stop(struct seq_file *seq, void *v)
{ }

static const struct seq_operations sel_avc_cache_stats_seq_ops = {
        .start          = sel_avc_stats_seq_start,
        .next           = sel_avc_stats_seq_next,
        .show           = sel_avc_stats_seq_show,
        .stop           = sel_avc_stats_seq_stop,
};

static int sel_open_avc_cache_stats(struct inode *inode, struct file *file)
{
        return seq_open(file, &sel_avc_cache_stats_seq_ops);
}

static const struct file_operations sel_avc_cache_stats_ops = {
        .open           = sel_open_avc_cache_stats,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};
#endif

static int sel_make_avc_files(struct dentry *dir)
{
        int i;
        static struct tree_descr files[] = {
                { "cache_threshold",
                  &sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
                { "hash_stats", &sel_avc_hash_stats_ops, S_IRUGO },
#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
                { "cache_stats", &sel_avc_cache_stats_ops, S_IRUGO },
#endif
        };

        for (i = 0; i < ARRAY_SIZE(files); i++) {
                struct inode *inode;
                struct dentry *dentry;

                dentry = d_alloc_name(dir, files[i].name);
                if (!dentry)
                        return -ENOMEM;

                inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
                if (!inode)
                        return -ENOMEM;

                inode->i_fop = files[i].ops;
                inode->i_ino = ++sel_last_ino;
                d_add(dentry, inode);
        }

        return 0;
}

static ssize_t sel_read_initcon(struct file *file, char __user *buf,
                                size_t count, loff_t *ppos)
{
        char *con;
        u32 sid, len;
        ssize_t ret;

        sid = file_inode(file)->i_ino&SEL_INO_MASK;
        ret = security_sid_to_context(sid, &con, &len);
        if (ret)
                return ret;

        ret = simple_read_from_buffer(buf, count, ppos, con, len);
        kfree(con);
        return ret;
}

static const struct file_operations sel_initcon_ops = {
        .read           = sel_read_initcon,
        .llseek         = generic_file_llseek,
};

static int sel_make_initcon_files(struct dentry *dir)
{
        int i;

        for (i = 1; i <= SECINITSID_NUM; i++) {
                struct inode *inode;
                struct dentry *dentry;
                dentry = d_alloc_name(dir, security_get_initial_sid_context(i));
                if (!dentry)
                        return -ENOMEM;

                inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
                if (!inode)
                        return -ENOMEM;

                inode->i_fop = &sel_initcon_ops;
                inode->i_ino = i|SEL_INITCON_INO_OFFSET;
                d_add(dentry, inode);
        }

        return 0;
}

static inline unsigned long sel_class_to_ino(u16 class)
{
        return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;
}

static inline u16 sel_ino_to_class(unsigned long ino)
{
        return (ino & SEL_INO_MASK) / (SEL_VEC_MAX + 1);
}

static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)
{
        return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;
}

static inline u32 sel_ino_to_perm(unsigned long ino)
{
        return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);
}

static ssize_t sel_read_class(struct file *file, char __user *buf,
                                size_t count, loff_t *ppos)
{
        unsigned long ino = file_inode(file)->i_ino;
        char res[TMPBUFLEN];
        ssize_t len = snprintf(res, sizeof(res), "%d", sel_ino_to_class(ino));
        return simple_read_from_buffer(buf, count, ppos, res, len);
}

static const struct file_operations sel_class_ops = {
        .read           = sel_read_class,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_read_perm(struct file *file, char __user *buf,
                                size_t count, loff_t *ppos)
{
        unsigned long ino = file_inode(file)->i_ino;
        char res[TMPBUFLEN];
        ssize_t len = snprintf(res, sizeof(res), "%d", sel_ino_to_perm(ino));
        return simple_read_from_buffer(buf, count, ppos, res, len);
}

static const struct file_operations sel_perm_ops = {
        .read           = sel_read_perm,
        .llseek         = generic_file_llseek,
};

static ssize_t sel_read_policycap(struct file *file, char __user *buf,
                                  size_t count, loff_t *ppos)
{
        int value;
        char tmpbuf[TMPBUFLEN];
        ssize_t length;
        unsigned long i_ino = file_inode(file)->i_ino;

        value = security_policycap_supported(i_ino & SEL_INO_MASK);
        length = scnprintf(tmpbuf, TMPBUFLEN, "%d", value);

        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

static const struct file_operations sel_policycap_ops = {
        .read           = sel_read_policycap,
        .llseek         = generic_file_llseek,
};

static int sel_make_perm_files(char *objclass, int classvalue,
                                struct dentry *dir)
{
        int i, rc, nperms;
        char **perms;

        rc = security_get_permissions(objclass, &perms, &nperms);
        if (rc)
                return rc;

        for (i = 0; i < nperms; i++) {
                struct inode *inode;
                struct dentry *dentry;

                rc = -ENOMEM;
                dentry = d_alloc_name(dir, perms[i]);
                if (!dentry)
                        goto out;

                rc = -ENOMEM;
                inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
                if (!inode)
                        goto out;

                inode->i_fop = &sel_perm_ops;
                /* i+1 since perm values are 1-indexed */
                inode->i_ino = sel_perm_to_ino(classvalue, i + 1);
                d_add(dentry, inode);
        }
        rc = 0;
out:
        for (i = 0; i < nperms; i++)
                kfree(perms[i]);
        kfree(perms);
        return rc;
}

static int sel_make_class_dir_entries(char *classname, int index,
                                        struct dentry *dir)
{
        struct dentry *dentry = NULL;
        struct inode *inode = NULL;
        int rc;

        dentry = d_alloc_name(dir, "index");
        if (!dentry)
                return -ENOMEM;

        inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
        if (!inode)
                return -ENOMEM;

        inode->i_fop = &sel_class_ops;
        inode->i_ino = sel_class_to_ino(index);
        d_add(dentry, inode);

        dentry = sel_make_dir(dir, "perms", &last_class_ino);
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);

        rc = sel_make_perm_files(classname, index, dentry);

        return rc;
}

static int sel_make_classes(void)
{
        int rc, nclasses, i;
        char **classes;

        /* delete any existing entries */
        sel_remove_entries(class_dir);

        rc = security_get_classes(&classes, &nclasses);
        if (rc)
                return rc;

        /* +2 since classes are 1-indexed */
        last_class_ino = sel_class_to_ino(nclasses + 2);

        for (i = 0; i < nclasses; i++) {
                struct dentry *class_name_dir;

                class_name_dir = sel_make_dir(class_dir, classes[i],
                                &last_class_ino);
                if (IS_ERR(class_name_dir)) {
                        rc = PTR_ERR(class_name_dir);
                        goto out;
                }

                /* i+1 since class values are 1-indexed */
                rc = sel_make_class_dir_entries(classes[i], i + 1,
                                class_name_dir);
                if (rc)
                        goto out;
        }
        rc = 0;
out:
        for (i = 0; i < nclasses; i++)
                kfree(classes[i]);
        kfree(classes);
        return rc;
}

static int sel_make_policycap(void)
{
        unsigned int iter;
        struct dentry *dentry = NULL;
        struct inode *inode = NULL;

        sel_remove_entries(policycap_dir);

        for (iter = 0; iter <= POLICYDB_CAPABILITY_MAX; iter++) {
                if (iter < ARRAY_SIZE(policycap_names))
                        dentry = d_alloc_name(policycap_dir,
                                              policycap_names[iter]);
                else
                        dentry = d_alloc_name(policycap_dir, "unknown");

                if (dentry == NULL)
                        return -ENOMEM;

                inode = sel_make_inode(policycap_dir->d_sb, S_IFREG | S_IRUGO);
                if (inode == NULL)
                        return -ENOMEM;

                inode->i_fop = &sel_policycap_ops;
                inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
                d_add(dentry, inode);
        }

        return 0;
}

static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
                        unsigned long *ino)
{
        struct dentry *dentry = d_alloc_name(dir, name);
        struct inode *inode;

        if (!dentry)
                return ERR_PTR(-ENOMEM);

        inode = sel_make_inode(dir->d_sb, S_IFDIR | S_IRUGO | S_IXUGO);
        if (!inode) {
                dput(dentry);
                return ERR_PTR(-ENOMEM);
        }

        inode->i_op = &simple_dir_inode_operations;
        inode->i_fop = &simple_dir_operations;
        inode->i_ino = ++(*ino);
        /* directory inodes start off with i_nlink == 2 (for "." entry) */
        inc_nlink(inode);
        d_add(dentry, inode);
        /* bump link count on parent directory, too */
        inc_nlink(d_inode(dir));

        return dentry;
}

static int sel_fill_super(struct super_block *sb, void *data, int silent)
{
        int ret;
        struct dentry *dentry;
        struct inode *inode;
        struct inode_security_struct *isec;

        static struct tree_descr selinux_files[] = {
                [SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
                [SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
                [SEL_CONTEXT] = {"context", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_USER] = {"user", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_POLICYVERS] = {"policyvers", &sel_policyvers_ops, S_IRUGO},
                [SEL_COMMIT_BOOLS] = {"commit_pending_bools", &sel_commit_bools_ops, S_IWUSR},
                [SEL_MLS] = {"mls", &sel_mls_ops, S_IRUGO},
                [SEL_DISABLE] = {"disable", &sel_disable_ops, S_IWUSR},
                [SEL_MEMBER] = {"member", &transaction_ops, S_IRUGO|S_IWUGO},
                [SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR},
                [SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO},
                [SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO},
                [SEL_STATUS] = {"status", &sel_handle_status_ops, S_IRUGO},
                [SEL_POLICY] = {"policy", &sel_policy_ops, S_IRUGO},
                [SEL_VALIDATE_TRANS] = {"validatetrans", &sel_transition_ops,
                                        S_IWUGO},
                /* last one */ {""}
        };
        ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
        if (ret)
                goto err;

        bool_dir = sel_make_dir(sb->s_root, BOOL_DIR_NAME, &sel_last_ino);
        if (IS_ERR(bool_dir)) {
                ret = PTR_ERR(bool_dir);
                bool_dir = NULL;
                goto err;
        }

        ret = -ENOMEM;
        dentry = d_alloc_name(sb->s_root, NULL_FILE_NAME);
        if (!dentry)
                goto err;

        ret = -ENOMEM;
        inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
        if (!inode)
                goto err;

        inode->i_ino = ++sel_last_ino;
        isec = (struct inode_security_struct *)inode->i_security;
        isec->sid = SECINITSID_DEVNULL;
        isec->sclass = SECCLASS_CHR_FILE;
        isec->initialized = LABEL_INITIALIZED;

        init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
        d_add(dentry, inode);
        selinux_null.dentry = dentry;

        dentry = sel_make_dir(sb->s_root, "avc", &sel_last_ino);
        if (IS_ERR(dentry)) {
                ret = PTR_ERR(dentry);
                goto err;
        }

        ret = sel_make_avc_files(dentry);
        if (ret)
                goto err;

        dentry = sel_make_dir(sb->s_root, "initial_contexts", &sel_last_ino);
        if (IS_ERR(dentry)) {
                ret = PTR_ERR(dentry);
                goto err;
        }

        ret = sel_make_initcon_files(dentry);
        if (ret)
                goto err;

        class_dir = sel_make_dir(sb->s_root, "class", &sel_last_ino);
        if (IS_ERR(class_dir)) {
                ret = PTR_ERR(class_dir);
                class_dir = NULL;
                goto err;
        }

        policycap_dir = sel_make_dir(sb->s_root, "policy_capabilities", &sel_last_ino);
        if (IS_ERR(policycap_dir)) {
                ret = PTR_ERR(policycap_dir);
                policycap_dir = NULL;
                goto err;
        }
        return 0;
err:
        printk(KERN_ERR "SELinux: %s:  failed while creating inodes\n",
                __func__);
        return ret;
}

static struct dentry *sel_mount(struct file_system_type *fs_type,
                      int flags, const char *dev_name, void *data)
{
        return mount_single(fs_type, flags, data, sel_fill_super);
}

static struct file_system_type sel_fs_type = {
        .name           = "selinuxfs",
        .mount          = sel_mount,
        .kill_sb        = kill_litter_super,
};

struct vfsmount *selinuxfs_mount;

static int __init init_sel_fs(void)
{
        int err;

        if (!selinux_enabled)
                return 0;

        err = sysfs_create_mount_point(fs_kobj, "selinux");
        if (err)
                return err;

        err = register_filesystem(&sel_fs_type);
        if (err) {
                sysfs_remove_mount_point(fs_kobj, "selinux");
                return err;
        }

        selinux_null.mnt = selinuxfs_mount = kern_mount(&sel_fs_type);
        if (IS_ERR(selinuxfs_mount)) {
                printk(KERN_ERR "selinuxfs:  could not mount!\n");
                err = PTR_ERR(selinuxfs_mount);
                selinuxfs_mount = NULL;
        }

        return err;
}

__initcall(init_sel_fs);

#ifdef CONFIG_SECURITY_SELINUX_DISABLE
void exit_sel_fs(void)
{
        sysfs_remove_mount_point(fs_kobj, "selinux");
        kern_unmount(selinuxfs_mount);
        unregister_filesystem(&sel_fs_type);
}
#endif