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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 char **bool_pending_names;
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 = filep->f_path.dentry->d_inode;
      unsigned index = inode->i_ino & SEL_INO_MASK;
      const char *name = filep->f_path.dentry->d_name.name;

      mutex_lock(&sel_mutex);

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

      if (count > PAGE_SIZE) {
            ret = -EINVAL;
            goto out;
      }
      if (!(page = (char*)get_zeroed_page(GFP_KERNEL))) {
            ret = -ENOMEM;
            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);
      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;
      int new_value;
      struct inode *inode = filep->f_path.dentry->d_inode;
      unsigned index = inode->i_ino & SEL_INO_MASK;
      const char *name = filep->f_path.dentry->d_name.name;

      mutex_lock(&sel_mutex);

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

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

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

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

      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)
            new_value = 1;

      bool_pending_values[index] = 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;
      int new_value;

      mutex_lock(&sel_mutex);

      length = task_has_security(current, SECURITY__SETBOOL);
      if (length)
            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;
      }

      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 && 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,
};

static void sel_remove_entries(struct dentry *de)
{
      struct list_head *node;

      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);
}

#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_names);
      kfree(bool_pending_values);
      bool_pending_names = NULL;
      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_names = names;
      bool_pending_values = values;
out:
      free_page((unsigned long)page);
      return ret;
err:
      if (names) {
            for (i = 0; i < num; i++)
                  kfree(names[i]);
            kfree(names);
      }
      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

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