Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...

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

/* Updated: Karl MacMillan <kmacmillan@tresys.com>
 *
 *      Added conditional policy language extensions
 *
 * 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 <asm/uaccess.h>
#include <asm/semaphore.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"

unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;

#ifdef CONFIG_SECURITY_SELINUX_ENABLE_SECMARK_DEFAULT
#define SELINUX_COMPAT_NET_VALUE 0
#else
#define SELINUX_COMPAT_NET_VALUE 1
#endif

int selinux_compat_net = SELINUX_COMPAT_NET_VALUE;

static int __init checkreqprot_setup(char *str)
{
        selinux_checkreqprot = simple_strtoul(str,NULL,0) ? 1 : 0;
        return 1;
}
__setup("checkreqprot=", checkreqprot_setup);

static int __init selinux_compat_net_setup(char *str)
{
        selinux_compat_net = simple_strtoul(str,NULL,0) ? 1 : 0;
        return 1;
}
__setup("selinux_compat_net=", selinux_compat_net_setup);


static DEFINE_MUTEX(sel_mutex);

/* global data for booleans */
static struct dentry *bool_dir = NULL;
static int bool_num = 0;
static int *bool_pending_values = NULL;

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

extern void selnl_notify_setenforce(int val);

/* Check whether a task is allowed to use a security operation. */
static int task_has_security(struct task_struct *tsk,
                             u32 perms)
{
        struct task_security_struct *tsec;

        tsec = tsk->security;
        if (!tsec)
                return -EACCES;

        return avc_has_perm(tsec->sid, SECINITSID_SECURITY,
                            SECCLASS_SECURITY, perms, NULL);
}

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_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_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;
        ssize_t length;
        int new_value;

        if (count >= PAGE_SIZE)
                return -ENOMEM;
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;

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

        if (new_value != selinux_enforcing) {
                length = task_has_security(current, SECURITY__SETENFORCE);
                if (length)
                        goto out;
                audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
                        "enforcing=%d old_enforcing=%d auid=%u", new_value, 
                        selinux_enforcing,
                        audit_get_loginuid(current->audit_context));
                selinux_enforcing = new_value;
                if (selinux_enforcing)
                        avc_ss_reset(0);
                selnl_notify_setenforce(selinux_enforcing);
        }
        length = count;
out:
        free_page((unsigned long) 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,
};

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 = filp->f_path.dentry->d_inode->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,
};

#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;
        extern int selinux_disable(void);

        if (count >= PAGE_SIZE)
                return -ENOMEM;
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;

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

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

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

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

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,
};

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

/* declaration for sel_make_class_dirs */
static int sel_make_dir(struct inode *dir, struct dentry *dentry,
                        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", selinux_mls_enabled);
        return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
}

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

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

{
        int ret;
        ssize_t length;
        void *data = NULL;

        mutex_lock(&sel_mutex);

        length = task_has_security(current, SECURITY__LOAD_POLICY);
        if (length)
                goto out;

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

        if ((count > 64 * 1024 * 1024)
            || (data = vmalloc(count)) == NULL) {
                length = -ENOMEM;
                goto out;
        }

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

        length = security_load_policy(data, count);
        if (length)
                goto out;

        ret = sel_make_bools();
        if (ret) {
                length = ret;
                goto out1;
        }

        ret = sel_make_classes();
        if (ret)
                length = ret;
        else
                length = count;

out1:

        printk(KERN_INFO "SELinux: policy loaded with handle_unknown=%s\n",
               (security_get_reject_unknown() ? "reject" :
                (security_get_allow_unknown() ? "allow" : "deny")));

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

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

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

        length = task_has_security(current, SECURITY__CHECK_CONTEXT);
        if (length)
                return length;

        length = security_context_to_sid(buf, size, &sid);
        if (length < 0)
                return length;

        length = security_sid_to_context(sid, &canon, &len);
        if (length < 0)
                return length;

        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "%s:  context size (%u) exceeds payload "
                       "max\n", __FUNCTION__, len);
                length = -ERANGE;
                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 = task_has_security(current, SECURITY__SETCHECKREQPROT);
        if (length)
                return length;

        if (count >= PAGE_SIZE)
                return -ENOMEM;
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;

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

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

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

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

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

        length = task_has_security(current, SECURITY__LOAD_POLICY);
        if (length)
                return length;

        if (count >= PAGE_SIZE)
                return -ENOMEM;
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;

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

        selinux_compat_net = new_value ? 1 : 0;
        length = count;
out:
        free_page((unsigned long) page);
        return length;
}
static const struct file_operations sel_compat_net_ops = {
        .read           = sel_read_compat_net,
        .write          = sel_write_compat_net,
};

/*
 * 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->f_path.dentry->d_inode->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,
};

/*
 * 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, *tcon;
        u32 ssid, tsid;
        u16 tclass;
        u32 req;
        struct av_decision avd;
        ssize_t length;

        length = task_has_security(current, SECURITY__COMPUTE_AV);
        if (length)
                return length;

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

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

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu %x", scon, tcon, &tclass, &req) != 4)
                goto out2;

        length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
        if (length < 0)
                goto out2;
        length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
        if (length < 0)
                goto out2;

        length = security_compute_av(ssid, tsid, tclass, req, &avd);
        if (length < 0)
                goto out2;

        length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
                          "%x %x %x %x %u",
                          avd.allowed, avd.decided,
                          avd.auditallow, avd.auditdeny,
                          avd.seqno);
out2:
        kfree(tcon);
out:
        kfree(scon);
        return length;
}

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

        length = task_has_security(current, SECURITY__COMPUTE_CREATE);
        if (length)
                return length;

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

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

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out2;

        length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
        if (length < 0)
                goto out2;
        length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
        if (length < 0)
                goto out2;

        length = security_transition_sid(ssid, tsid, tclass, &newsid);
        if (length < 0)
                goto out2;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length < 0)
                goto out2;

        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "%s:  context size (%u) exceeds payload "
                       "max\n", __FUNCTION__, len);
                length = -ERANGE;
                goto out3;
        }

        memcpy(buf, newcon, len);
        length = len;
out3:
        kfree(newcon);
out2:
        kfree(tcon);
out:
        kfree(scon);
        return length;
}

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

        length = task_has_security(current, SECURITY__COMPUTE_RELABEL);
        if (length)
                return length;

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

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

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out2;

        length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
        if (length < 0)
                goto out2;
        length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
        if (length < 0)
                goto out2;

        length = security_change_sid(ssid, tsid, tclass, &newsid);
        if (length < 0)
                goto out2;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length < 0)
                goto out2;

        if (len > SIMPLE_TRANSACTION_LIMIT) {
                length = -ERANGE;
                goto out3;
        }

        memcpy(buf, newcon, len);
        length = len;
out3:
        kfree(newcon);
out2:
        kfree(tcon);
out:
        kfree(scon);
        return length;
}

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

        length = task_has_security(current, SECURITY__COMPUTE_USER);
        if (length)
                return length;

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

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

        length = -EINVAL;
        if (sscanf(buf, "%s %s", con, user) != 2)
                goto out2;

        length = security_context_to_sid(con, strlen(con)+1, &sid);
        if (length < 0)
                goto out2;

        length = security_get_user_sids(sid, user, &sids, &nsids);
        if (length < 0)
                goto out2;

        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 out3;
                }
                if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
                        kfree(newcon);
                        length = -ERANGE;
                        goto out3;
                }
                memcpy(ptr, newcon, len);
                kfree(newcon);
                ptr += len;
                length += len;
        }
out3:
        kfree(sids);
out2:
        kfree(user);
out:
        kfree(con);
        return length;
}

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

        length = task_has_security(current, SECURITY__COMPUTE_MEMBER);
        if (length)
                return length;

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

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

        length = -EINVAL;
        if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
                goto out2;

        length = security_context_to_sid(scon, strlen(scon)+1, &ssid);
        if (length < 0)
                goto out2;
        length = security_context_to_sid(tcon, strlen(tcon)+1, &tsid);
        if (length < 0)
                goto out2;

        length = security_member_sid(ssid, tsid, tclass, &newsid);
        if (length < 0)
                goto out2;

        length = security_sid_to_context(newsid, &newcon, &len);
        if (length < 0)
                goto out2;

        if (len > SIMPLE_TRANSACTION_LIMIT) {
                printk(KERN_ERR "%s:  context size (%u) exceeds payload "
                       "max\n", __FUNCTION__, len);
                length = -ERANGE;
                goto out3;
        }

        memcpy(buf, newcon, len);
        length = len;
out3:
        kfree(newcon);
out2:
        kfree(tcon);
out:
        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_uid = ret->i_gid = 0;
                ret->i_blocks = 0;
                ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
        }
        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;
        struct inode *inode;

        mutex_lock(&sel_mutex);

        ret = -EFAULT;

        /* check to see if this file has been deleted */
        if (!filep->f_op)
                goto out;

        if (count > PAGE_SIZE) {
                ret = -EINVAL;
                goto out;
        }
        if (!(page = (char*)get_zeroed_page(GFP_KERNEL))) {
                ret = -ENOMEM;
                goto out;
        }

        inode = filep->f_path.dentry->d_inode;
        cur_enforcing = security_get_bool_value(inode->i_ino&SEL_INO_MASK);
        if (cur_enforcing < 0) {
                ret = cur_enforcing;
                goto out;
        }

        length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
                          bool_pending_values[inode->i_ino&SEL_INO_MASK]);
        ret = simple_read_from_buffer(buf, count, ppos, page, length);
out:
        mutex_unlock(&sel_mutex);
        if (page)
                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 = -EFAULT;
        int new_value;
        struct inode *inode;

        mutex_lock(&sel_mutex);

        length = task_has_security(current, SECURITY__SETBOOL);
        if (length)
                goto out;

        /* check to see if this file has been deleted */
        if (!filep->f_op)
                goto out;

        if (count >= PAGE_SIZE) {
                length = -ENOMEM;
                goto out;
        }
        if (*ppos != 0) {
                /* No partial writes. */
                goto out;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page) {
                length = -ENOMEM;
                goto out;
        }

        if (copy_from_user(page, buf, count))
                goto out;

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

        if (new_value)
                new_value = 1;

        inode = filep->f_path.dentry->d_inode;
        bool_pending_values[inode->i_ino&SEL_INO_MASK] = new_value;
        length = count;

out:
        mutex_unlock(&sel_mutex);
        if (page)
                free_page((unsigned long) page);
        return length;
}

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

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 = -EFAULT;
        int new_value;

        mutex_lock(&sel_mutex);

        length = task_has_security(current, SECURITY__SETBOOL);
        if (length)
                goto out;

        /* check to see if this file has been deleted */
        if (!filep->f_op)
                goto out;

        if (count >= PAGE_SIZE) {
                length = -ENOMEM;
                goto out;
        }
        if (*ppos != 0) {
                /* No partial writes. */
                goto out;
        }
        page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page) {
                length = -ENOMEM;
                goto out;
        }

        if (copy_from_user(page, buf, count))
                goto out;

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

        if (new_value && bool_pending_values) {
                security_set_bools(bool_num, bool_pending_values);
        }

        length = count;

out:
        mutex_unlock(&sel_mutex);
        if (page)
                free_page((unsigned long) page);
        return length;
}

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

/* partial revoke() from fs/proc/generic.c proc_kill_inodes */
static void sel_remove_entries(struct dentry *de)
{
        struct list_head *p, *node;
        struct super_block *sb = de->d_sb;

        spin_lock(&dcache_lock);
        node = de->d_subdirs.next;
        while (node != &de->d_subdirs) {
                struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
                list_del_init(node);

                if (d->d_inode) {
                        d = dget_locked(d);
                        spin_unlock(&dcache_lock);
                        d_delete(d);
                        simple_unlink(de->d_inode, d);
                        dput(d);
                        spin_lock(&dcache_lock);
                }
                node = de->d_subdirs.next;
        }

        spin_unlock(&dcache_lock);

        file_list_lock();
        list_for_each(p, &sb->s_files) {
                struct file * filp = list_entry(p, struct file, f_u.fu_list);
                struct dentry * dentry = filp->f_path.dentry;

                if (dentry->d_parent != de) {
                        continue;
                }
                filp->f_op = NULL;
        }
        file_list_unlock();
}

#define BOOL_DIR_NAME "booleans"

static int sel_make_bools(void)
{
        int i, ret = 0;
        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 */
        kfree(bool_pending_values);
        bool_pending_values = NULL;

        sel_remove_entries(dir);

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

        ret = security_get_bools(&num, &names, &values);
        if (ret != 0)
                goto out;

        for (i = 0; i < num; i++) {
                dentry = d_alloc_name(dir, names[i]);
                if (!dentry) {
                        ret = -ENOMEM;
                        goto err;
                }
                inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
                if (!inode) {
                        ret = -ENOMEM;
                        goto err;
                }

                len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
                if (len < 0) {
                        ret = -EINVAL;
                        goto err;
                } else if (len >= PAGE_SIZE) {
                        ret = -ENAMETOOLONG;
                        goto err;
                }
                isec = (struct inode_security_struct*)inode->i_security;
                if ((ret = security_genfs_sid("selinuxfs", page, SECCLASS_FILE, &sid)))
                        goto err;
                isec->sid = sid;
                isec->initialized = 1;
                inode->i_fop = &sel_bool_ops;
                inode->i_ino = i|SEL_BOOL_INO_OFFSET;
                d_add(dentry, inode);
        }
        bool_num = num;
        bool_pending_values = values;
out:
        free_page((unsigned long)page);
        if (names) {
                for (i = 0; i < num; i++)
                        kfree(names[i]);
                kfree(names);
        }
        return ret;
err:
        kfree(values);
        sel_remove_entries(dir);
        ret = -ENOMEM;
        goto out;
}

#define NULL_FILE_NAME "null"

struct dentry *selinux_null = 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;
        int new_value;

        if (count >= PAGE_SIZE) {
                ret = -ENOMEM;
                goto out;
        }

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

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

        if (copy_from_user(page, buf, count)) {
                ret = -EFAULT;
                goto out_free;
        }

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

        if (new_value != avc_cache_threshold) {
                ret = task_has_security(current, SECURITY__SETSECPARAM);
                if (ret)
                        goto out_free;
                avc_cache_threshold = new_value;
        }
        ret = count;
out_free:
        free_page((unsigned long)page);
out:
        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 ret = 0;

        page = (char *)__get_free_page(GFP_KERNEL);
        if (!page) {
                ret = -ENOMEM;
                goto out;
        }
        ret = avc_get_hash_stats(page);
        if (ret >= 0)
                ret = simple_read_from_buffer(buf, count, ppos, page, ret);
        free_page((unsigned long)page);
out:
        return ret;
}

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

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

#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_CPUS; ++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
                seq_printf(seq, "%u %u %u %u %u %u\n", st->lookups,
                           st->hits, st->misses, st->allocations,
                           st->reclaims, st->frees);
        return 0;
}

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

static 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, ret = 0;
        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) {
                        ret = -ENOMEM;
                        goto out;
                }

                inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
                if (!inode) {
                        ret = -ENOMEM;
                        goto out;
                }
                inode->i_fop = files[i].ops;
                inode->i_ino = ++sel_last_ino;
                d_add(dentry, inode);
        }
out:
        return ret;
}

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

        inode = file->f_path.dentry->d_inode;
        sid = inode->i_ino&SEL_INO_MASK;
        ret = security_sid_to_context(sid, &con, &len);
        if (ret < 0)
                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,
};

static int sel_make_initcon_files(struct dentry *dir)
{
        int i, ret = 0;

        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) {
                        ret = -ENOMEM;
                        goto out;
                }

                inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
                if (!inode) {
                        ret = -ENOMEM;
                        goto out;
                }
                inode->i_fop = &sel_initcon_ops;
                inode->i_ino = i|SEL_INITCON_INO_OFFSET;
                d_add(dentry, inode);
        }
out:
        return ret;
}

static inline unsigned int sel_div(unsigned long a, unsigned long b)
{
        return a / b - (a % b < 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 sel_div(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)
{
        ssize_t rc, len;
        char *page;
        unsigned long ino = file->f_path.dentry->d_inode->i_ino;

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

        len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));
        rc = simple_read_from_buffer(buf, count, ppos, page, len);
        free_page((unsigned long)page);
out:
        return rc;
}

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

static ssize_t sel_read_perm(struct file * file, char __user *buf,
                                size_t count, loff_t *ppos)
{
        ssize_t rc, len;
        char *page;
        unsigned long ino = file->f_path.dentry->d_inode->i_ino;

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

        len = snprintf(page, PAGE_SIZE,"%d", sel_ino_to_perm(ino));
        rc = simple_read_from_buffer(buf, count, ppos, page, len);
        free_page((unsigned long)page);
out:
        return rc;
}

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

static int sel_make_perm_files(char *objclass, int classvalue,
                                struct dentry *dir)
{
        int i, rc = 0, nperms;
        char **perms;

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

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

                dentry = d_alloc_name(dir, perms[i]);
                if (!dentry) {
                        rc = -ENOMEM;
                        goto out1;
                }

                inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
                if (!inode) {
                        rc = -ENOMEM;
                        goto out1;
                }
                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);
        }

out1:
        for (i = 0; i < nperms; i++)
                kfree(perms[i]);
        kfree(perms);
out:
        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) {
                rc = -ENOMEM;
                goto out;
        }

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

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

        dentry = d_alloc_name(dir, "perms");
        if (!dentry) {
                rc = -ENOMEM;
                goto out;
        }

        rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino);
        if (rc)
                goto out;

        rc = sel_make_perm_files(classname, index, dentry);

out:
        return rc;
}

static void sel_remove_classes(void)
{
        struct list_head *class_node;

        list_for_each(class_node, &class_dir->d_subdirs) {
                struct dentry *class_subdir = list_entry(class_node,
                                        struct dentry, d_u.d_child);
                struct list_head *class_subdir_node;

                list_for_each(class_subdir_node, &class_subdir->d_subdirs) {
                        struct dentry *d = list_entry(class_subdir_node,
                                                struct dentry, d_u.d_child);

                        if (d->d_inode)
                                if (d->d_inode->i_mode & S_IFDIR)
                                        sel_remove_entries(d);
                }

                sel_remove_entries(class_subdir);
        }

        sel_remove_entries(class_dir);
}

static int sel_make_classes(void)
{
        int rc = 0, nclasses, i;
        char **classes;

        /* delete any existing entries */
        sel_remove_classes();

        rc = security_get_classes(&classes, &nclasses);
        if (rc < 0)
                goto out;

        /* +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 = d_alloc_name(class_dir, classes[i]);
                if (!class_name_dir) {
                        rc = -ENOMEM;
                        goto out1;
                }

                rc = sel_make_dir(class_dir->d_inode, class_name_dir,
                                &last_class_ino);
                if (rc)
                        goto out1;

                /* i+1 since class values are 1-indexed */
                rc = sel_make_class_dir_entries(classes[i], i+1,
                                class_name_dir);
                if (rc)
                        goto out1;
        }

out1:
        for (i = 0; i < nclasses; i++)
                kfree(classes[i]);
        kfree(classes);
out:
        return rc;
}

static int sel_make_dir(struct inode *dir, struct dentry *dentry,
                        unsigned long *ino)
{
        int ret = 0;
        struct inode *inode;

        inode = sel_make_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
        if (!inode) {
                ret = -ENOMEM;
                goto out;
        }
        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(dir);
out:
        return ret;
}

static int sel_fill_super(struct super_block * sb, void * data, int silent)
{
        int ret;
        struct dentry *dentry;
        struct inode *inode, *root_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_COMPAT_NET] = {"compat_net", &sel_compat_net_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},
                /* last one */ {""}
        };
        ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
        if (ret)
                goto err;

        root_inode = sb->s_root->d_inode;

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

        ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
        if (ret)
                goto err;

        bool_dir = dentry;

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

        inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
        if (!inode) {
                ret = -ENOMEM;
                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 = 1;

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

        dentry = d_alloc_name(sb->s_root, "avc");
        if (!dentry) {
                ret = -ENOMEM;
                goto err;
        }

        ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
        if (ret)
                goto err;

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

        dentry = d_alloc_name(sb->s_root, "initial_contexts");
        if (!dentry) {
                ret = -ENOMEM;
                goto err;
        }

        ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
        if (ret)
                goto err;

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

        dentry = d_alloc_name(sb->s_root, "class");
        if (!dentry) {
                ret = -ENOMEM;
                goto err;
        }

        ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
        if (ret)
                goto err;

        class_dir = dentry;

out:
        return ret;
err:
        printk(KERN_ERR "%s:  failed while creating inodes\n", __FUNCTION__);
        goto out;
}

static int sel_get_sb(struct file_system_type *fs_type,
                      int flags, const char *dev_name, void *data,
                      struct vfsmount *mnt)
{
        return get_sb_single(fs_type, flags, data, sel_fill_super, mnt);
}

static struct file_system_type sel_fs_type = {
        .name           = "selinuxfs",
        .get_sb         = sel_get_sb,
        .kill_sb        = kill_litter_super,
};

struct vfsmount *selinuxfs_mount;

static int __init init_sel_fs(void)
{
        int err;

        if (!selinux_enabled)
                return 0;
        err = register_filesystem(&sel_fs_type);
        if (!err) {
                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)
{
        unregister_filesystem(&sel_fs_type);
}
#endif