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smack_lsm.c

/*
 *  Simplified MAC Kernel (smack) security module
 *
 *  This file contains the smack hook function implementations.
 *
 *  Author:
 *    Casey Schaufler <casey@schaufler-ca.com>
 *
 *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
 *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
 *                Paul Moore <paul.moore@hp.com>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License version 2,
 *      as published by the Free Software Foundation.
 */

#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/ext2_fs.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/audit.h>
#include "smack.h"

#define task_security(task)   (task_cred_xxx((task), security))

/*
 * I hope these are the hokeyist lines of code in the module. Casey.
 */
#define DEVPTS_SUPER_MAGIC    0x1cd1
#define SOCKFS_MAGIC          0x534F434B
#define TMPFS_MAGIC           0x01021994

/**
 * smk_fetch - Fetch the smack label from a file.
 * @ip: a pointer to the inode
 * @dp: a pointer to the dentry
 *
 * Returns a pointer to the master list entry for the Smack label
 * or NULL if there was no label to fetch.
 */
static char *smk_fetch(struct inode *ip, struct dentry *dp)
{
      int rc;
      char in[SMK_LABELLEN];

      if (ip->i_op->getxattr == NULL)
            return NULL;

      rc = ip->i_op->getxattr(dp, XATTR_NAME_SMACK, in, SMK_LABELLEN);
      if (rc < 0)
            return NULL;

      return smk_import(in, rc);
}

/**
 * new_inode_smack - allocate an inode security blob
 * @smack: a pointer to the Smack label to use in the blob
 *
 * Returns the new blob or NULL if there's no memory available
 */
struct inode_smack *new_inode_smack(char *smack)
{
      struct inode_smack *isp;

      isp = kzalloc(sizeof(struct inode_smack), GFP_KERNEL);
      if (isp == NULL)
            return NULL;

      isp->smk_inode = smack;
      isp->smk_flags = 0;
      mutex_init(&isp->smk_lock);

      return isp;
}

/*
 * LSM hooks.
 * We he, that is fun!
 */

/**
 * smack_ptrace_may_access - Smack approval on PTRACE_ATTACH
 * @ctp: child task pointer
 * @mode: ptrace attachment mode
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require read and write.
 */
static int smack_ptrace_may_access(struct task_struct *ctp, unsigned int mode)
{
      int rc;
      struct smk_audit_info ad;
      char *sp, *tsp;

      rc = cap_ptrace_may_access(ctp, mode);
      if (rc != 0)
            return rc;

      sp = current_security();
      tsp = task_security(ctp);
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, ctp);

      /* we won't log here, because rc can be overriden */
      rc = smk_access(sp, tsp, MAY_READWRITE, NULL);
      if (rc != 0 && capable(CAP_MAC_OVERRIDE))
            rc = 0;

      smack_log(sp, tsp, MAY_READWRITE, rc, &ad);
      return rc;
}

/**
 * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
 * @ptp: parent task pointer
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require read and write.
 */
static int smack_ptrace_traceme(struct task_struct *ptp)
{
      int rc;
      struct smk_audit_info ad;
      char *sp, *tsp;

      rc = cap_ptrace_traceme(ptp);
      if (rc != 0)
            return rc;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, ptp);

      sp = current_security();
      tsp = task_security(ptp);
      /* we won't log here, because rc can be overriden */
      rc = smk_access(tsp, sp, MAY_READWRITE, NULL);
      if (rc != 0 && has_capability(ptp, CAP_MAC_OVERRIDE))
            rc = 0;

      smack_log(tsp, sp, MAY_READWRITE, rc, &ad);
      return rc;
}

/**
 * smack_syslog - Smack approval on syslog
 * @type: message type
 *
 * Require that the task has the floor label
 *
 * Returns 0 on success, error code otherwise.
 */
static int smack_syslog(int type)
{
      int rc;
      char *sp = current_security();

      rc = cap_syslog(type);
      if (rc != 0)
            return rc;

      if (capable(CAP_MAC_OVERRIDE))
            return 0;

       if (sp != smack_known_floor.smk_known)
            rc = -EACCES;

      return rc;
}


/*
 * Superblock Hooks.
 */

/**
 * smack_sb_alloc_security - allocate a superblock blob
 * @sb: the superblock getting the blob
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_sb_alloc_security(struct super_block *sb)
{
      struct superblock_smack *sbsp;

      sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL);

      if (sbsp == NULL)
            return -ENOMEM;

      sbsp->smk_root = smack_known_floor.smk_known;
      sbsp->smk_default = smack_known_floor.smk_known;
      sbsp->smk_floor = smack_known_floor.smk_known;
      sbsp->smk_hat = smack_known_hat.smk_known;
      sbsp->smk_initialized = 0;
      spin_lock_init(&sbsp->smk_sblock);

      sb->s_security = sbsp;

      return 0;
}

/**
 * smack_sb_free_security - free a superblock blob
 * @sb: the superblock getting the blob
 *
 */
static void smack_sb_free_security(struct super_block *sb)
{
      kfree(sb->s_security);
      sb->s_security = NULL;
}

/**
 * smack_sb_copy_data - copy mount options data for processing
 * @orig: where to start
 * @smackopts: mount options string
 *
 * Returns 0 on success or -ENOMEM on error.
 *
 * Copy the Smack specific mount options out of the mount
 * options list.
 */
static int smack_sb_copy_data(char *orig, char *smackopts)
{
      char *cp, *commap, *otheropts, *dp;

      otheropts = (char *)get_zeroed_page(GFP_KERNEL);
      if (otheropts == NULL)
            return -ENOMEM;

      for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
            if (strstr(cp, SMK_FSDEFAULT) == cp)
                  dp = smackopts;
            else if (strstr(cp, SMK_FSFLOOR) == cp)
                  dp = smackopts;
            else if (strstr(cp, SMK_FSHAT) == cp)
                  dp = smackopts;
            else if (strstr(cp, SMK_FSROOT) == cp)
                  dp = smackopts;
            else
                  dp = otheropts;

            commap = strchr(cp, ',');
            if (commap != NULL)
                  *commap = '\0';

            if (*dp != '\0')
                  strcat(dp, ",");
            strcat(dp, cp);
      }

      strcpy(orig, otheropts);
      free_page((unsigned long)otheropts);

      return 0;
}

/**
 * smack_sb_kern_mount - Smack specific mount processing
 * @sb: the file system superblock
 * @flags: the mount flags
 * @data: the smack mount options
 *
 * Returns 0 on success, an error code on failure
 */
static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
{
      struct dentry *root = sb->s_root;
      struct inode *inode = root->d_inode;
      struct superblock_smack *sp = sb->s_security;
      struct inode_smack *isp;
      char *op;
      char *commap;
      char *nsp;

      spin_lock(&sp->smk_sblock);
      if (sp->smk_initialized != 0) {
            spin_unlock(&sp->smk_sblock);
            return 0;
      }
      sp->smk_initialized = 1;
      spin_unlock(&sp->smk_sblock);

      for (op = data; op != NULL; op = commap) {
            commap = strchr(op, ',');
            if (commap != NULL)
                  *commap++ = '\0';

            if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
                  op += strlen(SMK_FSHAT);
                  nsp = smk_import(op, 0);
                  if (nsp != NULL)
                        sp->smk_hat = nsp;
            } else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
                  op += strlen(SMK_FSFLOOR);
                  nsp = smk_import(op, 0);
                  if (nsp != NULL)
                        sp->smk_floor = nsp;
            } else if (strncmp(op, SMK_FSDEFAULT,
                           strlen(SMK_FSDEFAULT)) == 0) {
                  op += strlen(SMK_FSDEFAULT);
                  nsp = smk_import(op, 0);
                  if (nsp != NULL)
                        sp->smk_default = nsp;
            } else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
                  op += strlen(SMK_FSROOT);
                  nsp = smk_import(op, 0);
                  if (nsp != NULL)
                        sp->smk_root = nsp;
            }
      }

      /*
       * Initialize the root inode.
       */
      isp = inode->i_security;
      if (isp == NULL)
            inode->i_security = new_inode_smack(sp->smk_root);
      else
            isp->smk_inode = sp->smk_root;

      return 0;
}

/**
 * smack_sb_statfs - Smack check on statfs
 * @dentry: identifies the file system in question
 *
 * Returns 0 if current can read the floor of the filesystem,
 * and error code otherwise
 */
static int smack_sb_statfs(struct dentry *dentry)
{
      struct superblock_smack *sbp = dentry->d_sb->s_security;
      int rc;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
      return rc;
}

/**
 * smack_sb_mount - Smack check for mounting
 * @dev_name: unused
 * @path: mount point
 * @type: unused
 * @flags: unused
 * @data: unused
 *
 * Returns 0 if current can write the floor of the filesystem
 * being mounted on, an error code otherwise.
 */
static int smack_sb_mount(char *dev_name, struct path *path,
                    char *type, unsigned long flags, void *data)
{
      struct superblock_smack *sbp = path->mnt->mnt_sb->s_security;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path(&ad, *path);

      return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad);
}

/**
 * smack_sb_umount - Smack check for unmounting
 * @mnt: file system to unmount
 * @flags: unused
 *
 * Returns 0 if current can write the floor of the filesystem
 * being unmounted, an error code otherwise.
 */
static int smack_sb_umount(struct vfsmount *mnt, int flags)
{
      struct superblock_smack *sbp;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, mnt->mnt_mountpoint);
      smk_ad_setfield_u_fs_path_mnt(&ad, mnt);

      sbp = mnt->mnt_sb->s_security;
      return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad);
}

/*
 * Inode hooks
 */

/**
 * smack_inode_alloc_security - allocate an inode blob
 * @inode: the inode in need of a blob
 *
 * Returns 0 if it gets a blob, -ENOMEM otherwise
 */
static int smack_inode_alloc_security(struct inode *inode)
{
      inode->i_security = new_inode_smack(current_security());
      if (inode->i_security == NULL)
            return -ENOMEM;
      return 0;
}

/**
 * smack_inode_free_security - free an inode blob
 * @inode: the inode with a blob
 *
 * Clears the blob pointer in inode
 */
static void smack_inode_free_security(struct inode *inode)
{
      kfree(inode->i_security);
      inode->i_security = NULL;
}

/**
 * smack_inode_init_security - copy out the smack from an inode
 * @inode: the inode
 * @dir: unused
 * @name: where to put the attribute name
 * @value: where to put the attribute value
 * @len: where to put the length of the attribute
 *
 * Returns 0 if it all works out, -ENOMEM if there's no memory
 */
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
                             char **name, void **value, size_t *len)
{
      char *isp = smk_of_inode(inode);

      if (name) {
            *name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL);
            if (*name == NULL)
                  return -ENOMEM;
      }

      if (value) {
            *value = kstrdup(isp, GFP_KERNEL);
            if (*value == NULL)
                  return -ENOMEM;
      }

      if (len)
            *len = strlen(isp) + 1;

      return 0;
}

/**
 * smack_inode_link - Smack check on link
 * @old_dentry: the existing object
 * @dir: unused
 * @new_dentry: the new object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
                      struct dentry *new_dentry)
{
      char *isp;
      struct smk_audit_info ad;
      int rc;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

      isp = smk_of_inode(old_dentry->d_inode);
      rc = smk_curacc(isp, MAY_WRITE, &ad);

      if (rc == 0 && new_dentry->d_inode != NULL) {
            isp = smk_of_inode(new_dentry->d_inode);
            smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
            rc = smk_curacc(isp, MAY_WRITE, &ad);
      }

      return rc;
}

/**
 * smack_inode_unlink - Smack check on inode deletion
 * @dir: containing directory object
 * @dentry: file to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the object, error code otherwise
 */
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
      struct inode *ip = dentry->d_inode;
      struct smk_audit_info ad;
      int rc;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      /*
       * You need write access to the thing you're unlinking
       */
      rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
      if (rc == 0) {
            /*
             * You also need write access to the containing directory
             */
            smk_ad_setfield_u_fs_path_dentry(&ad, NULL);
            smk_ad_setfield_u_fs_inode(&ad, dir);
            rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
      }
      return rc;
}

/**
 * smack_inode_rmdir - Smack check on directory deletion
 * @dir: containing directory object
 * @dentry: directory to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the directory, error code otherwise
 */
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
      struct smk_audit_info ad;
      int rc;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      /*
       * You need write access to the thing you're removing
       */
      rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
      if (rc == 0) {
            /*
             * You also need write access to the containing directory
             */
            smk_ad_setfield_u_fs_path_dentry(&ad, NULL);
            smk_ad_setfield_u_fs_inode(&ad, dir);
            rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
      }

      return rc;
}

/**
 * smack_inode_rename - Smack check on rename
 * @old_inode: the old directory
 * @old_dentry: unused
 * @new_inode: the new directory
 * @new_dentry: unused
 *
 * Read and write access is required on both the old and
 * new directories.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_rename(struct inode *old_inode,
                        struct dentry *old_dentry,
                        struct inode *new_inode,
                        struct dentry *new_dentry)
{
      int rc;
      char *isp;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

      isp = smk_of_inode(old_dentry->d_inode);
      rc = smk_curacc(isp, MAY_READWRITE, &ad);

      if (rc == 0 && new_dentry->d_inode != NULL) {
            isp = smk_of_inode(new_dentry->d_inode);
            smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
            rc = smk_curacc(isp, MAY_READWRITE, &ad);
      }
      return rc;
}

/**
 * smack_inode_permission - Smack version of permission()
 * @inode: the inode in question
 * @mask: the access requested
 *
 * This is the important Smack hook.
 *
 * Returns 0 if access is permitted, -EACCES otherwise
 */
static int smack_inode_permission(struct inode *inode, int mask)
{
      struct smk_audit_info ad;
      /*
       * No permission to check. Existence test. Yup, it's there.
       */
      if (mask == 0)
            return 0;
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_inode(&ad, inode);
      return smk_curacc(smk_of_inode(inode), mask, &ad);
}

/**
 * smack_inode_setattr - Smack check for setting attributes
 * @dentry: the object
 * @iattr: for the force flag
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
      struct smk_audit_info ad;
      /*
       * Need to allow for clearing the setuid bit.
       */
      if (iattr->ia_valid & ATTR_FORCE)
            return 0;
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
}

/**
 * smack_inode_getattr - Smack check for getting attributes
 * @mnt: unused
 * @dentry: the object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
      smk_ad_setfield_u_fs_path_mnt(&ad, mnt);
      return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}

/**
 * smack_inode_setxattr - Smack check for setting xattrs
 * @dentry: the object
 * @name: name of the attribute
 * @value: unused
 * @size: unused
 * @flags: unused
 *
 * This protects the Smack attribute explicitly.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setxattr(struct dentry *dentry, const char *name,
                        const void *value, size_t size, int flags)
{
      struct smk_audit_info ad;
      int rc = 0;

      if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
          strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
          strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
            if (!capable(CAP_MAC_ADMIN))
                  rc = -EPERM;
            /*
             * check label validity here so import wont fail on
             * post_setxattr
             */
            if (size == 0 || size >= SMK_LABELLEN ||
                smk_import(value, size) == NULL)
                  rc = -EINVAL;
      } else
            rc = cap_inode_setxattr(dentry, name, value, size, flags);

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      if (rc == 0)
            rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);

      return rc;
}

/**
 * smack_inode_post_setxattr - Apply the Smack update approved above
 * @dentry: object
 * @name: attribute name
 * @value: attribute value
 * @size: attribute size
 * @flags: unused
 *
 * Set the pointer in the inode blob to the entry found
 * in the master label list.
 */
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
                              const void *value, size_t size, int flags)
{
      struct inode_smack *isp;
      char *nsp;

      /*
       * Not SMACK
       */
      if (strcmp(name, XATTR_NAME_SMACK))
            return;

      isp = dentry->d_inode->i_security;

      /*
       * No locking is done here. This is a pointer
       * assignment.
       */
      nsp = smk_import(value, size);
      if (nsp != NULL)
            isp->smk_inode = nsp;
      else
            isp->smk_inode = smack_known_invalid.smk_known;

      return;
}

/*
 * smack_inode_getxattr - Smack check on getxattr
 * @dentry: the object
 * @name: unused
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

      return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
}

/*
 * smack_inode_removexattr - Smack check on removexattr
 * @dentry: the object
 * @name: name of the attribute
 *
 * Removing the Smack attribute requires CAP_MAC_ADMIN
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_removexattr(struct dentry *dentry, const char *name)
{
      struct smk_audit_info ad;
      int rc = 0;

      if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
          strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
          strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
            if (!capable(CAP_MAC_ADMIN))
                  rc = -EPERM;
      } else
            rc = cap_inode_removexattr(dentry, name);

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
      if (rc == 0)
            rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);

      return rc;
}

/**
 * smack_inode_getsecurity - get smack xattrs
 * @inode: the object
 * @name: attribute name
 * @buffer: where to put the result
 * @alloc: unused
 *
 * Returns the size of the attribute or an error code
 */
static int smack_inode_getsecurity(const struct inode *inode,
                           const char *name, void **buffer,
                           bool alloc)
{
      struct socket_smack *ssp;
      struct socket *sock;
      struct super_block *sbp;
      struct inode *ip = (struct inode *)inode;
      char *isp;
      int ilen;
      int rc = 0;

      if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
            isp = smk_of_inode(inode);
            ilen = strlen(isp) + 1;
            *buffer = isp;
            return ilen;
      }

      /*
       * The rest of the Smack xattrs are only on sockets.
       */
      sbp = ip->i_sb;
      if (sbp->s_magic != SOCKFS_MAGIC)
            return -EOPNOTSUPP;

      sock = SOCKET_I(ip);
      if (sock == NULL || sock->sk == NULL)
            return -EOPNOTSUPP;

      ssp = sock->sk->sk_security;

      if (strcmp(name, XATTR_SMACK_IPIN) == 0)
            isp = ssp->smk_in;
      else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
            isp = ssp->smk_out;
      else
            return -EOPNOTSUPP;

      ilen = strlen(isp) + 1;
      if (rc == 0) {
            *buffer = isp;
            rc = ilen;
      }

      return rc;
}


/**
 * smack_inode_listsecurity - list the Smack attributes
 * @inode: the object
 * @buffer: where they go
 * @buffer_size: size of buffer
 *
 * Returns 0 on success, -EINVAL otherwise
 */
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
                            size_t buffer_size)
{
      int len = strlen(XATTR_NAME_SMACK);

      if (buffer != NULL && len <= buffer_size) {
            memcpy(buffer, XATTR_NAME_SMACK, len);
            return len;
      }
      return -EINVAL;
}

/**
 * smack_inode_getsecid - Extract inode's security id
 * @inode: inode to extract the info from
 * @secid: where result will be saved
 */
static void smack_inode_getsecid(const struct inode *inode, u32 *secid)
{
      struct inode_smack *isp = inode->i_security;

      *secid = smack_to_secid(isp->smk_inode);
}

/*
 * File Hooks
 */

/**
 * smack_file_permission - Smack check on file operations
 * @file: unused
 * @mask: unused
 *
 * Returns 0
 *
 * Should access checks be done on each read or write?
 * UNICOS and SELinux say yes.
 * Trusted Solaris, Trusted Irix, and just about everyone else says no.
 *
 * I'll say no for now. Smack does not do the frequent
 * label changing that SELinux does.
 */
static int smack_file_permission(struct file *file, int mask)
{
      return 0;
}

/**
 * smack_file_alloc_security - assign a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no allocation is done.
 *
 * Returns 0
 */
static int smack_file_alloc_security(struct file *file)
{
      file->f_security = current_security();
      return 0;
}

/**
 * smack_file_free_security - clear a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no memory is freed.
 */
static void smack_file_free_security(struct file *file)
{
      file->f_security = NULL;
}

/**
 * smack_file_ioctl - Smack check on ioctls
 * @file: the object
 * @cmd: what to do
 * @arg: unused
 *
 * Relies heavily on the correct use of the ioctl command conventions.
 *
 * Returns 0 if allowed, error code otherwise
 */
static int smack_file_ioctl(struct file *file, unsigned int cmd,
                      unsigned long arg)
{
      int rc = 0;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path(&ad, file->f_path);

      if (_IOC_DIR(cmd) & _IOC_WRITE)
            rc = smk_curacc(file->f_security, MAY_WRITE, &ad);

      if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
            rc = smk_curacc(file->f_security, MAY_READ, &ad);

      return rc;
}

/**
 * smack_file_lock - Smack check on file locking
 * @file: the object
 * @cmd: unused
 *
 * Returns 0 if current has write access, error code otherwise
 */
static int smack_file_lock(struct file *file, unsigned int cmd)
{
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path_dentry(&ad, file->f_path.dentry);
      return smk_curacc(file->f_security, MAY_WRITE, &ad);
}

/**
 * smack_file_fcntl - Smack check on fcntl
 * @file: the object
 * @cmd: what action to check
 * @arg: unused
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_fcntl(struct file *file, unsigned int cmd,
                      unsigned long arg)
{
      struct smk_audit_info ad;
      int rc;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
      smk_ad_setfield_u_fs_path(&ad, file->f_path);

      switch (cmd) {
      case F_DUPFD:
      case F_GETFD:
      case F_GETFL:
      case F_GETLK:
      case F_GETOWN:
      case F_GETSIG:
            rc = smk_curacc(file->f_security, MAY_READ, &ad);
            break;
      case F_SETFD:
      case F_SETFL:
      case F_SETLK:
      case F_SETLKW:
      case F_SETOWN:
      case F_SETSIG:
            rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
            break;
      default:
            rc = smk_curacc(file->f_security, MAY_READWRITE, &ad);
      }

      return rc;
}

/**
 * smack_file_set_fowner - set the file security blob value
 * @file: object in question
 *
 * Returns 0
 * Further research may be required on this one.
 */
static int smack_file_set_fowner(struct file *file)
{
      file->f_security = current_security();
      return 0;
}

/**
 * smack_file_send_sigiotask - Smack on sigio
 * @tsk: The target task
 * @fown: the object the signal come from
 * @signum: unused
 *
 * Allow a privileged task to get signals even if it shouldn't
 *
 * Returns 0 if a subject with the object's smack could
 * write to the task, an error code otherwise.
 */
static int smack_file_send_sigiotask(struct task_struct *tsk,
                             struct fown_struct *fown, int signum)
{
      struct file *file;
      int rc;
      char *tsp = tsk->cred->security;
      struct smk_audit_info ad;

      /*
       * struct fown_struct is never outside the context of a struct file
       */
      file = container_of(fown, struct file, f_owner);
      /* we don't log here as rc can be overriden */
      rc = smk_access(file->f_security, tsp, MAY_WRITE, NULL);
      if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
            rc = 0;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, tsk);
      smack_log(file->f_security, tsp, MAY_WRITE, rc, &ad);
      return rc;
}

/**
 * smack_file_receive - Smack file receive check
 * @file: the object
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_receive(struct file *file)
{
      int may = 0;
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_fs_path(&ad, file->f_path);
      /*
       * This code relies on bitmasks.
       */
      if (file->f_mode & FMODE_READ)
            may = MAY_READ;
      if (file->f_mode & FMODE_WRITE)
            may |= MAY_WRITE;

      return smk_curacc(file->f_security, may, &ad);
}

/*
 * Task hooks
 */

/**
 * smack_cred_free - "free" task-level security credentials
 * @cred: the credentials in question
 *
 * Smack isn't using copies of blobs. Everyone
 * points to an immutable list. The blobs never go away.
 * There is no leak here.
 */
static void smack_cred_free(struct cred *cred)
{
      cred->security = NULL;
}

/**
 * smack_cred_prepare - prepare new set of credentials for modification
 * @new: the new credentials
 * @old: the original credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a new set of credentials for modification.
 */
static int smack_cred_prepare(struct cred *new, const struct cred *old,
                        gfp_t gfp)
{
      new->security = old->security;
      return 0;
}

/**
 * smack_cred_commit - commit new credentials
 * @new: the new credentials
 * @old: the original credentials
 */
static void smack_cred_commit(struct cred *new, const struct cred *old)
{
}

/**
 * smack_kernel_act_as - Set the subjective context in a set of credentials
 * @new: points to the set of credentials to be modified.
 * @secid: specifies the security ID to be set
 *
 * Set the security data for a kernel service.
 */
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
      char *smack = smack_from_secid(secid);

      if (smack == NULL)
            return -EINVAL;

      new->security = smack;
      return 0;
}

/**
 * smack_kernel_create_files_as - Set the file creation label in a set of creds
 * @new: points to the set of credentials to be modified
 * @inode: points to the inode to use as a reference
 *
 * Set the file creation context in a set of credentials to the same
 * as the objective context of the specified inode
 */
static int smack_kernel_create_files_as(struct cred *new,
                              struct inode *inode)
{
      struct inode_smack *isp = inode->i_security;

      new->security = isp->smk_inode;
      return 0;
}

/**
 * smk_curacc_on_task - helper to log task related access
 * @p: the task object
 * @access : the access requested
 *
 * Return 0 if access is permitted
 */
static int smk_curacc_on_task(struct task_struct *p, int access)
{
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, p);
      return smk_curacc(task_security(p), access, &ad);
}

/**
 * smack_task_setpgid - Smack check on setting pgid
 * @p: the task object
 * @pgid: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
      return smk_curacc_on_task(p, MAY_WRITE);
}

/**
 * smack_task_getpgid - Smack access check for getpgid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getpgid(struct task_struct *p)
{
      return smk_curacc_on_task(p, MAY_READ);
}

/**
 * smack_task_getsid - Smack access check for getsid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getsid(struct task_struct *p)
{
      return smk_curacc_on_task(p, MAY_READ);
}

/**
 * smack_task_getsecid - get the secid of the task
 * @p: the object task
 * @secid: where to put the result
 *
 * Sets the secid to contain a u32 version of the smack label.
 */
static void smack_task_getsecid(struct task_struct *p, u32 *secid)
{
      *secid = smack_to_secid(task_security(p));
}

/**
 * smack_task_setnice - Smack check on setting nice
 * @p: the task object
 * @nice: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setnice(struct task_struct *p, int nice)
{
      int rc;

      rc = cap_task_setnice(p, nice);
      if (rc == 0)
            rc = smk_curacc_on_task(p, MAY_WRITE);
      return rc;
}

/**
 * smack_task_setioprio - Smack check on setting ioprio
 * @p: the task object
 * @ioprio: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
      int rc;

      rc = cap_task_setioprio(p, ioprio);
      if (rc == 0)
            rc = smk_curacc_on_task(p, MAY_WRITE);
      return rc;
}

/**
 * smack_task_getioprio - Smack check on reading ioprio
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getioprio(struct task_struct *p)
{
      return smk_curacc_on_task(p, MAY_READ);
}

/**
 * smack_task_setscheduler - Smack check on setting scheduler
 * @p: the task object
 * @policy: unused
 * @lp: unused
 *
 * Return 0 if read access is permitted
 */
static int smack_task_setscheduler(struct task_struct *p, int policy,
                           struct sched_param *lp)
{
      int rc;

      rc = cap_task_setscheduler(p, policy, lp);
      if (rc == 0)
            rc = smk_curacc_on_task(p, MAY_WRITE);
      return rc;
}

/**
 * smack_task_getscheduler - Smack check on reading scheduler
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getscheduler(struct task_struct *p)
{
      return smk_curacc_on_task(p, MAY_READ);
}

/**
 * smack_task_movememory - Smack check on moving memory
 * @p: the task object
 *
 * Return 0 if write access is permitted
 */
static int smack_task_movememory(struct task_struct *p)
{
      return smk_curacc_on_task(p, MAY_WRITE);
}

/**
 * smack_task_kill - Smack check on signal delivery
 * @p: the task object
 * @info: unused
 * @sig: unused
 * @secid: identifies the smack to use in lieu of current's
 *
 * Return 0 if write access is permitted
 *
 * The secid behavior is an artifact of an SELinux hack
 * in the USB code. Someday it may go away.
 */
static int smack_task_kill(struct task_struct *p, struct siginfo *info,
                     int sig, u32 secid)
{
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, p);
      /*
       * Sending a signal requires that the sender
       * can write the receiver.
       */
      if (secid == 0)
            return smk_curacc(task_security(p), MAY_WRITE, &ad);
      /*
       * If the secid isn't 0 we're dealing with some USB IO
       * specific behavior. This is not clean. For one thing
       * we can't take privilege into account.
       */
      return smk_access(smack_from_secid(secid), task_security(p),
                    MAY_WRITE, &ad);
}

/**
 * smack_task_wait - Smack access check for waiting
 * @p: task to wait for
 *
 * Returns 0 if current can wait for p, error code otherwise
 */
static int smack_task_wait(struct task_struct *p)
{
      struct smk_audit_info ad;
      char *sp = current_security();
      char *tsp = task_security(p);
      int rc;

      /* we don't log here, we can be overriden */
      rc = smk_access(sp, tsp, MAY_WRITE, NULL);
      if (rc == 0)
            goto out_log;

      /*
       * Allow the operation to succeed if either task
       * has privilege to perform operations that might
       * account for the smack labels having gotten to
       * be different in the first place.
       *
       * This breaks the strict subject/object access
       * control ideal, taking the object's privilege
       * state into account in the decision as well as
       * the smack value.
       */
      if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE))
            rc = 0;
      /* we log only if we didn't get overriden */
 out_log:
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
      smk_ad_setfield_u_tsk(&ad, p);
      smack_log(sp, tsp, MAY_WRITE, rc, &ad);
      return rc;
}

/**
 * smack_task_to_inode - copy task smack into the inode blob
 * @p: task to copy from
 * @inode: inode to copy to
 *
 * Sets the smack pointer in the inode security blob
 */
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
      struct inode_smack *isp = inode->i_security;
      isp->smk_inode = task_security(p);
}

/*
 * Socket hooks.
 */

/**
 * smack_sk_alloc_security - Allocate a socket blob
 * @sk: the socket
 * @family: unused
 * @gfp_flags: memory allocation flags
 *
 * Assign Smack pointers to current
 *
 * Returns 0 on success, -ENOMEM is there's no memory
 */
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
      char *csp = current_security();
      struct socket_smack *ssp;

      ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
      if (ssp == NULL)
            return -ENOMEM;

      ssp->smk_in = csp;
      ssp->smk_out = csp;
      ssp->smk_packet[0] = '\0';

      sk->sk_security = ssp;

      return 0;
}

/**
 * smack_sk_free_security - Free a socket blob
 * @sk: the socket
 *
 * Clears the blob pointer
 */
static void smack_sk_free_security(struct sock *sk)
{
      kfree(sk->sk_security);
}

/**
* smack_host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts.  The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static char *smack_host_label(struct sockaddr_in *sip)
{
      struct smk_netlbladdr *snp;
      struct in_addr *siap = &sip->sin_addr;

      if (siap->s_addr == 0)
            return NULL;

      list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list)
            /*
            * we break after finding the first match because
            * the list is sorted from longest to shortest mask
            * so we have found the most specific match
            */
            if ((&snp->smk_host.sin_addr)->s_addr ==
                (siap->s_addr & (&snp->smk_mask)->s_addr)) {
                  /* we have found the special CIPSO option */
                  if (snp->smk_label == smack_cipso_option)
                        return NULL;
                  return snp->smk_label;
            }

      return NULL;
}

/**
 * smack_set_catset - convert a capset to netlabel mls categories
 * @catset: the Smack categories
 * @sap: where to put the netlabel categories
 *
 * Allocates and fills attr.mls.cat
 */
static void smack_set_catset(char *catset, struct netlbl_lsm_secattr *sap)
{
      unsigned char *cp;
      unsigned char m;
      int cat;
      int rc;
      int byte;

      if (!catset)
            return;

      sap->flags |= NETLBL_SECATTR_MLS_CAT;
      sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
      sap->attr.mls.cat->startbit = 0;

      for (cat = 1, cp = catset, byte = 0; byte < SMK_LABELLEN; cp++, byte++)
            for (m = 0x80; m != 0; m >>= 1, cat++) {
                  if ((m & *cp) == 0)
                        continue;
                  rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
                                            cat, GFP_ATOMIC);
            }
}

/**
 * smack_to_secattr - fill a secattr from a smack value
 * @smack: the smack value
 * @nlsp: where the result goes
 *
 * Casey says that CIPSO is good enough for now.
 * It can be used to effect.
 * It can also be abused to effect when necessary.
 * Appologies to the TSIG group in general and GW in particular.
 */
static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
{
      struct smack_cipso cipso;
      int rc;

      nlsp->domain = smack;
      nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;

      rc = smack_to_cipso(smack, &cipso);
      if (rc == 0) {
            nlsp->attr.mls.lvl = cipso.smk_level;
            smack_set_catset(cipso.smk_catset, nlsp);
      } else {
            nlsp->attr.mls.lvl = smack_cipso_direct;
            smack_set_catset(smack, nlsp);
      }
}

/**
 * smack_netlabel - Set the secattr on a socket
 * @sk: the socket
 * @labeled: socket label scheme
 *
 * Convert the outbound smack value (smk_out) to a
 * secattr and attach it to the socket.
 *
 * Returns 0 on success or an error code
 */
static int smack_netlabel(struct sock *sk, int labeled)
{
      struct socket_smack *ssp = sk->sk_security;
      struct netlbl_lsm_secattr secattr;
      int rc = 0;

      /*
       * Usually the netlabel code will handle changing the
       * packet labeling based on the label.
       * The case of a single label host is different, because
       * a single label host should never get a labeled packet
       * even though the label is usually associated with a packet
       * label.
       */
      local_bh_disable();
      bh_lock_sock_nested(sk);

      if (ssp->smk_out == smack_net_ambient ||
          labeled == SMACK_UNLABELED_SOCKET)
            netlbl_sock_delattr(sk);
      else {
            netlbl_secattr_init(&secattr);
            smack_to_secattr(ssp->smk_out, &secattr);
            rc = netlbl_sock_setattr(sk, sk->sk_family, &secattr);
            netlbl_secattr_destroy(&secattr);
      }

      bh_unlock_sock(sk);
      local_bh_enable();

      return rc;
}

/**
 * smack_netlbel_send - Set the secattr on a socket and perform access checks
 * @sk: the socket
 * @sap: the destination address
 *
 * Set the correct secattr for the given socket based on the destination
 * address and perform any outbound access checks needed.
 *
 * Returns 0 on success or an error code.
 *
 */
static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
{
      int rc;
      int sk_lbl;
      char *hostsp;
      struct socket_smack *ssp = sk->sk_security;
      struct smk_audit_info ad;

      rcu_read_lock();
      hostsp = smack_host_label(sap);
      if (hostsp != NULL) {
            sk_lbl = SMACK_UNLABELED_SOCKET;
#ifdef CONFIG_AUDIT
            smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
            ad.a.u.net.family = sap->sin_family;
            ad.a.u.net.dport = sap->sin_port;
            ad.a.u.net.v4info.daddr = sap->sin_addr.s_addr;
#endif
            rc = smk_access(ssp->smk_out, hostsp, MAY_WRITE, &ad);
      } else {
            sk_lbl = SMACK_CIPSO_SOCKET;
            rc = 0;
      }
      rcu_read_unlock();
      if (rc != 0)
            return rc;

      return smack_netlabel(sk, sk_lbl);
}

/**
 * smack_inode_setsecurity - set smack xattrs
 * @inode: the object
 * @name: attribute name
 * @value: attribute value
 * @size: size of the attribute
 * @flags: unused
 *
 * Sets the named attribute in the appropriate blob
 *
 * Returns 0 on success, or an error code
 */
static int smack_inode_setsecurity(struct inode *inode, const char *name,
                           const void *value, size_t size, int flags)
{
      char *sp;
      struct inode_smack *nsp = inode->i_security;
      struct socket_smack *ssp;
      struct socket *sock;
      int rc = 0;

      if (value == NULL || size > SMK_LABELLEN || size == 0)
            return -EACCES;

      sp = smk_import(value, size);
      if (sp == NULL)
            return -EINVAL;

      if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
            nsp->smk_inode = sp;
            return 0;
      }
      /*
       * The rest of the Smack xattrs are only on sockets.
       */
      if (inode->i_sb->s_magic != SOCKFS_MAGIC)
            return -EOPNOTSUPP;

      sock = SOCKET_I(inode);
      if (sock == NULL || sock->sk == NULL)
            return -EOPNOTSUPP;

      ssp = sock->sk->sk_security;

      if (strcmp(name, XATTR_SMACK_IPIN) == 0)
            ssp->smk_in = sp;
      else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
            ssp->smk_out = sp;
            rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
            if (rc != 0)
                  printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
                         __func__, -rc);
      } else
            return -EOPNOTSUPP;

      return 0;
}

/**
 * smack_socket_post_create - finish socket setup
 * @sock: the socket
 * @family: protocol family
 * @type: unused
 * @protocol: unused
 * @kern: unused
 *
 * Sets the netlabel information on the socket
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_post_create(struct socket *sock, int family,
                            int type, int protocol, int kern)
{
      if (family != PF_INET || sock->sk == NULL)
            return 0;
      /*
       * Set the outbound netlbl.
       */
      return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
}

/**
 * smack_socket_connect - connect access check
 * @sock: the socket
 * @sap: the other end
 * @addrlen: size of sap
 *
 * Verifies that a connection may be possible
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
                        int addrlen)
{
      if (sock->sk == NULL || sock->sk->sk_family != PF_INET)
            return 0;
      if (addrlen < sizeof(struct sockaddr_in))
            return -EINVAL;

      return smack_netlabel_send(sock->sk, (struct sockaddr_in *)sap);
}

/**
 * smack_flags_to_may - convert S_ to MAY_ values
 * @flags: the S_ value
 *
 * Returns the equivalent MAY_ value
 */
static int smack_flags_to_may(int flags)
{
      int may = 0;

      if (flags & S_IRUGO)
            may |= MAY_READ;
      if (flags & S_IWUGO)
            may |= MAY_WRITE;
      if (flags & S_IXUGO)
            may |= MAY_EXEC;

      return may;
}

/**
 * smack_msg_msg_alloc_security - Set the security blob for msg_msg
 * @msg: the object
 *
 * Returns 0
 */
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
      msg->security = current_security();
      return 0;
}

/**
 * smack_msg_msg_free_security - Clear the security blob for msg_msg
 * @msg: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_msg_free_security(struct msg_msg *msg)
{
      msg->security = NULL;
}

/**
 * smack_of_shm - the smack pointer for the shm
 * @shp: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_shm(struct shmid_kernel *shp)
{
      return (char *)shp->shm_perm.security;
}

/**
 * smack_shm_alloc_security - Set the security blob for shm
 * @shp: the object
 *
 * Returns 0
 */
static int smack_shm_alloc_security(struct shmid_kernel *shp)
{
      struct kern_ipc_perm *isp = &shp->shm_perm;

      isp->security = current_security();
      return 0;
}

/**
 * smack_shm_free_security - Clear the security blob for shm
 * @shp: the object
 *
 * Clears the blob pointer
 */
static void smack_shm_free_security(struct shmid_kernel *shp)
{
      struct kern_ipc_perm *isp = &shp->shm_perm;

      isp->security = NULL;
}

/**
 * smk_curacc_shm : check if current has access on shm
 * @shp : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_shm(struct shmid_kernel *shp, int access)
{
      char *ssp = smack_of_shm(shp);
      struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
      ad.a.u.ipc_id = shp->shm_perm.id;
#endif
      return smk_curacc(ssp, access, &ad);
}

/**
 * smack_shm_associate - Smack access check for shm
 * @shp: the object
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_associate(struct shmid_kernel *shp, int shmflg)
{
      int may;

      may = smack_flags_to_may(shmflg);
      return smk_curacc_shm(shp, may);
}

/**
 * smack_shm_shmctl - Smack access check for shm
 * @shp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd)
{
      int may;

      switch (cmd) {
      case IPC_STAT:
      case SHM_STAT:
            may = MAY_READ;
            break;
      case IPC_SET:
      case SHM_LOCK:
      case SHM_UNLOCK:
      case IPC_RMID:
            may = MAY_READWRITE;
            break;
      case IPC_INFO:
      case SHM_INFO:
            /*
             * System level information.
             */
            return 0;
      default:
            return -EINVAL;
      }
      return smk_curacc_shm(shp, may);
}

/**
 * smack_shm_shmat - Smack access for shmat
 * @shp: the object
 * @shmaddr: unused
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
                     int shmflg)
{
      int may;

      may = smack_flags_to_may(shmflg);
      return smk_curacc_shm(shp, may);
}

/**
 * smack_of_sem - the smack pointer for the sem
 * @sma: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_sem(struct sem_array *sma)
{
      return (char *)sma->sem_perm.security;
}

/**
 * smack_sem_alloc_security - Set the security blob for sem
 * @sma: the object
 *
 * Returns 0
 */
static int smack_sem_alloc_security(struct sem_array *sma)
{
      struct kern_ipc_perm *isp = &sma->sem_perm;

      isp->security = current_security();
      return 0;
}

/**
 * smack_sem_free_security - Clear the security blob for sem
 * @sma: the object
 *
 * Clears the blob pointer
 */
static void smack_sem_free_security(struct sem_array *sma)
{
      struct kern_ipc_perm *isp = &sma->sem_perm;

      isp->security = NULL;
}

/**
 * smk_curacc_sem : check if current has access on sem
 * @sma : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_sem(struct sem_array *sma, int access)
{
      char *ssp = smack_of_sem(sma);
      struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
      ad.a.u.ipc_id = sma->sem_perm.id;
#endif
      return smk_curacc(ssp, access, &ad);
}

/**
 * smack_sem_associate - Smack access check for sem
 * @sma: the object
 * @semflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_associate(struct sem_array *sma, int semflg)
{
      int may;

      may = smack_flags_to_may(semflg);
      return smk_curacc_sem(sma, may);
}

/**
 * smack_sem_shmctl - Smack access check for sem
 * @sma: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_semctl(struct sem_array *sma, int cmd)
{
      int may;

      switch (cmd) {
      case GETPID:
      case GETNCNT:
      case GETZCNT:
      case GETVAL:
      case GETALL:
      case IPC_STAT:
      case SEM_STAT:
            may = MAY_READ;
            break;
      case SETVAL:
      case SETALL:
      case IPC_RMID:
      case IPC_SET:
            may = MAY_READWRITE;
            break;
      case IPC_INFO:
      case SEM_INFO:
            /*
             * System level information
             */
            return 0;
      default:
            return -EINVAL;
      }

      return smk_curacc_sem(sma, may);
}

/**
 * smack_sem_semop - Smack checks of semaphore operations
 * @sma: the object
 * @sops: unused
 * @nsops: unused
 * @alter: unused
 *
 * Treated as read and write in all cases.
 *
 * Returns 0 if access is allowed, error code otherwise
 */
static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
                     unsigned nsops, int alter)
{
      return smk_curacc_sem(sma, MAY_READWRITE);
}

/**
 * smack_msg_alloc_security - Set the security blob for msg
 * @msq: the object
 *
 * Returns 0
 */
static int smack_msg_queue_alloc_security(struct msg_queue *msq)
{
      struct kern_ipc_perm *kisp = &msq->q_perm;

      kisp->security = current_security();
      return 0;
}

/**
 * smack_msg_free_security - Clear the security blob for msg
 * @msq: the object
 *
 * Clears the blob pointer
 */
static void smack_msg_queue_free_security(struct msg_queue *msq)
{
      struct kern_ipc_perm *kisp = &msq->q_perm;

      kisp->security = NULL;
}

/**
 * smack_of_msq - the smack pointer for the msq
 * @msq: the object
 *
 * Returns a pointer to the smack value
 */
static char *smack_of_msq(struct msg_queue *msq)
{
      return (char *)msq->q_perm.security;
}

/**
 * smk_curacc_msq : helper to check if current has access on msq
 * @msq : the msq
 * @access : access requested
 *
 * return 0 if current has access, error otherwise
 */
static int smk_curacc_msq(struct msg_queue *msq, int access)
{
      char *msp = smack_of_msq(msq);
      struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
      ad.a.u.ipc_id = msq->q_perm.id;
#endif
      return smk_curacc(msp, access, &ad);
}

/**
 * smack_msg_queue_associate - Smack access check for msg_queue
 * @msq: the object
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg)
{
      int may;

      may = smack_flags_to_may(msqflg);
      return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgctl - Smack access check for msg_queue
 * @msq: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
{
      int may;

      switch (cmd) {
      case IPC_STAT:
      case MSG_STAT:
            may = MAY_READ;
            break;
      case IPC_SET:
      case IPC_RMID:
            may = MAY_READWRITE;
            break;
      case IPC_INFO:
      case MSG_INFO:
            /*
             * System level information
             */
            return 0;
      default:
            return -EINVAL;
      }

      return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg,
                          int msqflg)
{
      int may;

      may = smack_flags_to_may(msqflg);
      return smk_curacc_msq(msq, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @msq: the object
 * @msg: unused
 * @target: unused
 * @type: unused
 * @mode: unused
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
                  struct task_struct *target, long type, int mode)
{
      return smk_curacc_msq(msq, MAY_READWRITE);
}

/**
 * smack_ipc_permission - Smack access for ipc_permission()
 * @ipp: the object permissions
 * @flag: access requested
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
      char *isp = ipp->security;
      int may = smack_flags_to_may(flag);
      struct smk_audit_info ad;

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
      ad.a.u.ipc_id = ipp->id;
#endif
      return smk_curacc(isp, may, &ad);
}

/**
 * smack_ipc_getsecid - Extract smack security id
 * @ipp: the object permissions
 * @secid: where result will be saved
 */
static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
{
      char *smack = ipp->security;

      *secid = smack_to_secid(smack);
}

/**
 * smack_d_instantiate - Make sure the blob is correct on an inode
 * @opt_dentry: unused
 * @inode: the object
 *
 * Set the inode's security blob if it hasn't been done already.
 */
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
      struct super_block *sbp;
      struct superblock_smack *sbsp;
      struct inode_smack *isp;
      char *csp = current_security();
      char *fetched;
      char *final;
      struct dentry *dp;

      if (inode == NULL)
            return;

      isp = inode->i_security;

      mutex_lock(&isp->smk_lock);
      /*
       * If the inode is already instantiated
       * take the quick way out
       */
      if (isp->smk_flags & SMK_INODE_INSTANT)
            goto unlockandout;

      sbp = inode->i_sb;
      sbsp = sbp->s_security;
      /*
       * We're going to use the superblock default label
       * if there's no label on the file.
       */
      final = sbsp->smk_default;

      /*
       * If this is the root inode the superblock
       * may be in the process of initialization.
       * If that is the case use the root value out
       * of the superblock.
       */
      if (opt_dentry->d_parent == opt_dentry) {
            isp->smk_inode = sbsp->smk_root;
            isp->smk_flags |= SMK_INODE_INSTANT;
            goto unlockandout;
      }

      /*
       * This is pretty hackish.
       * Casey says that we shouldn't have to do
       * file system specific code, but it does help
       * with keeping it simple.
       */
      switch (sbp->s_magic) {
      case SMACK_MAGIC:
            /*
             * Casey says that it's a little embarassing
             * that the smack file system doesn't do
             * extended attributes.
             */
            final = smack_known_star.smk_known;
            break;
      case PIPEFS_MAGIC:
            /*
             * Casey says pipes are easy (?)
             */
            final = smack_known_star.smk_known;
            break;
      case DEVPTS_SUPER_MAGIC:
            /*
             * devpts seems content with the label of the task.
             * Programs that change smack have to treat the
             * pty with respect.
             */
            final = csp;
            break;
      case SOCKFS_MAGIC:
            /*
             * Casey says sockets get the smack of the task.
             */
            final = csp;
            break;
      case PROC_SUPER_MAGIC:
            /*
             * Casey says procfs appears not to care.
             * The superblock default suffices.
             */
            break;
      case TMPFS_MAGIC:
            /*
             * Device labels should come from the filesystem,
             * but watch out, because they're volitile,
             * getting recreated on every reboot.
             */
            final = smack_known_star.smk_known;
            /*
             * No break.
             *
             * If a smack value has been set we want to use it,
             * but since tmpfs isn't giving us the opportunity
             * to set mount options simulate setting the
             * superblock default.
             */
      default:
            /*
             * This isn't an understood special case.
             * Get the value from the xattr.
             *
             * No xattr support means, alas, no SMACK label.
             * Use the aforeapplied default.
             * It would be curious if the label of the task
             * does not match that assigned.
             */
            if (inode->i_op->getxattr == NULL)
                  break;
            /*
             * Get the dentry for xattr.
             */
            if (opt_dentry == NULL) {
                  dp = d_find_alias(inode);
                  if (dp == NULL)
                        break;
            } else {
                  dp = dget(opt_dentry);
                  if (dp == NULL)
                        break;
            }

            fetched = smk_fetch(inode, dp);
            if (fetched != NULL)
                  final = fetched;

            dput(dp);
            break;
      }

      if (final == NULL)
            isp->smk_inode = csp;
      else
            isp->smk_inode = final;

      isp->smk_flags |= SMK_INODE_INSTANT;

unlockandout:
      mutex_unlock(&isp->smk_lock);
      return;
}

/**
 * smack_getprocattr - Smack process attribute access
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: where to put the result
 *
 * Places a copy of the task Smack into value
 *
 * Returns the length of the smack label or an error code
 */
static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
      char *cp;
      int slen;

      if (strcmp(name, "current") != 0)
            return -EINVAL;

      cp = kstrdup(task_security(p), GFP_KERNEL);
      if (cp == NULL)
            return -ENOMEM;

      slen = strlen(cp);
      *value = cp;
      return slen;
}

/**
 * smack_setprocattr - Smack process attribute setting
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: the value to set
 * @size: the size of the value
 *
 * Sets the Smack value of the task. Only setting self
 * is permitted and only with privilege
 *
 * Returns the length of the smack label or an error code
 */
static int smack_setprocattr(struct task_struct *p, char *name,
                       void *value, size_t size)
{
      struct cred *new;
      char *newsmack;

      /*
       * Changing another process' Smack value is too dangerous
       * and supports no sane use case.
       */
      if (p != current)
            return -EPERM;

      if (!capable(CAP_MAC_ADMIN))
            return -EPERM;

      if (value == NULL || size == 0 || size >= SMK_LABELLEN)
            return -EINVAL;

      if (strcmp(name, "current") != 0)
            return -EINVAL;

      newsmack = smk_import(value, size);
      if (newsmack == NULL)
            return -EINVAL;

      /*
       * No process is ever allowed the web ("@") label.
       */
      if (newsmack == smack_known_web.smk_known)
            return -EPERM;

      new = prepare_creds();
      if (new == NULL)
            return -ENOMEM;
      new->security = newsmack;
      commit_creds(new);
      return size;
}

/**
 * smack_unix_stream_connect - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 * @newsk: unused
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_stream_connect(struct socket *sock,
                             struct socket *other, struct sock *newsk)
{
      struct inode *sp = SOCK_INODE(sock);
      struct inode *op = SOCK_INODE(other);
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
      smk_ad_setfield_u_net_sk(&ad, other->sk);
      return smk_access(smk_of_inode(sp), smk_of_inode(op),
                         MAY_READWRITE, &ad);
}

/**
 * smack_unix_may_send - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
      struct inode *sp = SOCK_INODE(sock);
      struct inode *op = SOCK_INODE(other);
      struct smk_audit_info ad;

      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
      smk_ad_setfield_u_net_sk(&ad, other->sk);
      return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_WRITE, &ad);
}

/**
 * smack_socket_sendmsg - Smack check based on destination host
 * @sock: the socket
 * @msg: the message
 * @size: the size of the message
 *
 * Return 0 if the current subject can write to the destination
 * host. This is only a question if the destination is a single
 * label host.
 */
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
                        int size)
{
      struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;

      /*
       * Perfectly reasonable for this to be NULL
       */
      if (sip == NULL || sip->sin_family != PF_INET)
            return 0;

      return smack_netlabel_send(sock->sk, sip);
}


/**
 * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
 * @sap: netlabel secattr
 * @sip: where to put the result
 *
 * Copies a smack label into sip
 */
static void smack_from_secattr(struct netlbl_lsm_secattr *sap, char *sip)
{
      char smack[SMK_LABELLEN];
      char *sp;
      int pcat;

      if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
            /*
             * Looks like a CIPSO packet.
             * If there are flags but no level netlabel isn't
             * behaving the way we expect it to.
             *
             * Get the categories, if any
             * Without guidance regarding the smack value
             * for the packet fall back on the network
             * ambient value.
             */
            memset(smack, '\0', SMK_LABELLEN);
            if ((sap->flags & NETLBL_SECATTR_MLS_CAT) != 0)
                  for (pcat = -1;;) {
                        pcat = netlbl_secattr_catmap_walk(
                              sap->attr.mls.cat, pcat + 1);
                        if (pcat < 0)
                              break;
                        smack_catset_bit(pcat, smack);
                  }
            /*
             * If it is CIPSO using smack direct mapping
             * we are already done. WeeHee.
             */
            if (sap->attr.mls.lvl == smack_cipso_direct) {
                  memcpy(sip, smack, SMK_MAXLEN);
                  return;
            }
            /*
             * Look it up in the supplied table if it is not
             * a direct mapping.
             */
            smack_from_cipso(sap->attr.mls.lvl, smack, sip);
            return;
      }
      if ((sap->flags & NETLBL_SECATTR_SECID) != 0) {
            /*
             * Looks like a fallback, which gives us a secid.
             */
            sp = smack_from_secid(sap->attr.secid);
            /*
             * This has got to be a bug because it is
             * impossible to specify a fallback without
             * specifying the label, which will ensure
             * it has a secid, and the only way to get a
             * secid is from a fallback.
             */
            BUG_ON(sp == NULL);
            strncpy(sip, sp, SMK_MAXLEN);
            return;
      }
      /*
       * Without guidance regarding the smack value
       * for the packet fall back on the network
       * ambient value.
       */
      strncpy(sip, smack_net_ambient, SMK_MAXLEN);
      return;
}

/**
 * smack_socket_sock_rcv_skb - Smack packet delivery access check
 * @sk: socket
 * @skb: packet
 *
 * Returns 0 if the packet should be delivered, an error code otherwise
 */
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
      struct netlbl_lsm_secattr secattr;
      struct socket_smack *ssp = sk->sk_security;
      char smack[SMK_LABELLEN];
      char *csp;
      int rc;
      struct smk_audit_info ad;
      if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
            return 0;

      /*
       * Translate what netlabel gave us.
       */
      netlbl_secattr_init(&secattr);

      rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr);
      if (rc == 0) {
            smack_from_secattr(&secattr, smack);
            csp = smack;
      } else
            csp = smack_net_ambient;

      netlbl_secattr_destroy(&secattr);

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
      ad.a.u.net.family = sk->sk_family;
      ad.a.u.net.netif = skb->iif;
      ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
      /*
       * Receiving a packet requires that the other end
       * be able to write here. Read access is not required.
       * This is the simplist possible security model
       * for networking.
       */
      rc = smk_access(csp, ssp->smk_in, MAY_WRITE, &ad);
      if (rc != 0)
            netlbl_skbuff_err(skb, rc, 0);
      return rc;
}

/**
 * smack_socket_getpeersec_stream - pull in packet label
 * @sock: the socket
 * @optval: user's destination
 * @optlen: size thereof
 * @len: max thereof
 *
 * returns zero on success, an error code otherwise
 */
static int smack_socket_getpeersec_stream(struct socket *sock,
                                char __user *optval,
                                int __user *optlen, unsigned len)
{
      struct socket_smack *ssp;
      int slen;
      int rc = 0;

      ssp = sock->sk->sk_security;
      slen = strlen(ssp->smk_packet) + 1;

      if (slen > len)
            rc = -ERANGE;
      else if (copy_to_user(optval, ssp->smk_packet, slen) != 0)
            rc = -EFAULT;

      if (put_user(slen, optlen) != 0)
            rc = -EFAULT;

      return rc;
}


/**
 * smack_socket_getpeersec_dgram - pull in packet label
 * @sock: the socket
 * @skb: packet data
 * @secid: pointer to where to put the secid of the packet
 *
 * Sets the netlabel socket state on sk from parent
 */
static int smack_socket_getpeersec_dgram(struct socket *sock,
                               struct sk_buff *skb, u32 *secid)

{
      struct netlbl_lsm_secattr secattr;
      struct sock *sk;
      char smack[SMK_LABELLEN];
      int family = PF_INET;
      u32 s;
      int rc;

      /*
       * Only works for families with packets.
       */
      if (sock != NULL) {
            sk = sock->sk;
            if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)
                  return 0;
            family = sk->sk_family;
      }
      /*
       * Translate what netlabel gave us.
       */
      netlbl_secattr_init(&secattr);
      rc = netlbl_skbuff_getattr(skb, family, &secattr);
      if (rc == 0)
            smack_from_secattr(&secattr, smack);
      netlbl_secattr_destroy(&secattr);

      /*
       * Give up if we couldn't get anything
       */
      if (rc != 0)
            return rc;

      s = smack_to_secid(smack);
      if (s == 0)
            return -EINVAL;

      *secid = s;
      return 0;
}

/**
 * smack_sock_graft - Initialize a newly created socket with an existing sock
 * @sk: child sock
 * @parent: parent socket
 *
 * Set the smk_{in,out} state of an existing sock based on the process that
 * is creating the new socket.
 */
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
      struct socket_smack *ssp;

      if (sk == NULL ||
          (sk->sk_family != PF_INET && sk->sk_family != PF_INET6))
            return;

      ssp = sk->sk_security;
      ssp->smk_in = ssp->smk_out = current_security();
      /* cssp->smk_packet is already set in smack_inet_csk_clone() */
}

/**
 * smack_inet_conn_request - Smack access check on connect
 * @sk: socket involved
 * @skb: packet
 * @req: unused
 *
 * Returns 0 if a task with the packet label could write to
 * the socket, otherwise an error code
 */
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
                           struct request_sock *req)
{
      u16 family = sk->sk_family;
      struct socket_smack *ssp = sk->sk_security;
      struct netlbl_lsm_secattr secattr;
      struct sockaddr_in addr;
      struct iphdr *hdr;
      char smack[SMK_LABELLEN];
      int rc;
      struct smk_audit_info ad;

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

      netlbl_secattr_init(&secattr);
      rc = netlbl_skbuff_getattr(skb, family, &secattr);
      if (rc == 0)
            smack_from_secattr(&secattr, smack);
      else
            strncpy(smack, smack_known_huh.smk_known, SMK_MAXLEN);
      netlbl_secattr_destroy(&secattr);

#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET);
      ad.a.u.net.family = family;
      ad.a.u.net.netif = skb->iif;
      ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
      /*
       * Receiving a packet requires that the other end be able to write
       * here. Read access is not required.
       */
      rc = smk_access(smack, ssp->smk_in, MAY_WRITE, &ad);
      if (rc != 0)
            return rc;

      /*
       * Save the peer's label in the request_sock so we can later setup
       * smk_packet in the child socket so that SO_PEERCRED can report it.
       */
      req->peer_secid = smack_to_secid(smack);

      /*
       * We need to decide if we want to label the incoming connection here
       * if we do we only need to label the request_sock and the stack will
       * propogate the wire-label to the sock when it is created.
       */
      hdr = ip_hdr(skb);
      addr.sin_addr.s_addr = hdr->saddr;
      rcu_read_lock();
      if (smack_host_label(&addr) == NULL) {
            rcu_read_unlock();
            netlbl_secattr_init(&secattr);
            smack_to_secattr(smack, &secattr);
            rc = netlbl_req_setattr(req, &secattr);
            netlbl_secattr_destroy(&secattr);
      } else {
            rcu_read_unlock();
            netlbl_req_delattr(req);
      }

      return rc;
}

/**
 * smack_inet_csk_clone - Copy the connection information to the new socket
 * @sk: the new socket
 * @req: the connection's request_sock
 *
 * Transfer the connection's peer label to the newly created socket.
 */
static void smack_inet_csk_clone(struct sock *sk,
                         const struct request_sock *req)
{
      struct socket_smack *ssp = sk->sk_security;
      char *smack;

      if (req->peer_secid != 0) {
            smack = smack_from_secid(req->peer_secid);
            strncpy(ssp->smk_packet, smack, SMK_MAXLEN);
      } else
            ssp->smk_packet[0] = '\0';
}

/*
 * Key management security hooks
 *
 * Casey has not tested key support very heavily.
 * The permission check is most likely too restrictive.
 * If you care about keys please have a look.
 */
#ifdef CONFIG_KEYS

/**
 * smack_key_alloc - Set the key security blob
 * @key: object
 * @cred: the credentials to use
 * @flags: unused
 *
 * No allocation required
 *
 * Returns 0
 */
static int smack_key_alloc(struct key *key, const struct cred *cred,
                     unsigned long flags)
{
      key->security = cred->security;
      return 0;
}

/**
 * smack_key_free - Clear the key security blob
 * @key: the object
 *
 * Clear the blob pointer
 */
static void smack_key_free(struct key *key)
{
      key->security = NULL;
}

/*
 * smack_key_permission - Smack access on a key
 * @key_ref: gets to the object
 * @cred: the credentials to use
 * @perm: unused
 *
 * Return 0 if the task has read and write to the object,
 * an error code otherwise
 */
static int smack_key_permission(key_ref_t key_ref,
                        const struct cred *cred, key_perm_t perm)
{
      struct key *keyp;
      struct smk_audit_info ad;

      keyp = key_ref_to_ptr(key_ref);
      if (keyp == NULL)
            return -EINVAL;
      /*
       * If the key hasn't been initialized give it access so that
       * it may do so.
       */
      if (keyp->security == NULL)
            return 0;
      /*
       * This should not occur
       */
      if (cred->security == NULL)
            return -EACCES;
#ifdef CONFIG_AUDIT
      smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
      ad.a.u.key_struct.key = keyp->serial;
      ad.a.u.key_struct.key_desc = keyp->description;
#endif
      return smk_access(cred->security, keyp->security,
                         MAY_READWRITE, &ad);
}
#endif /* CONFIG_KEYS */

/*
 * Smack Audit hooks
 *
 * Audit requires a unique representation of each Smack specific
 * rule. This unique representation is used to distinguish the
 * object to be audited from remaining kernel objects and also
 * works as a glue between the audit hooks.
 *
 * Since repository entries are added but never deleted, we'll use
 * the smack_known label address related to the given audit rule as
 * the needed unique representation. This also better fits the smack
 * model where nearly everything is a label.
 */
#ifdef CONFIG_AUDIT

/**
 * smack_audit_rule_init - Initialize a smack audit rule
 * @field: audit rule fields given from user-space (audit.h)
 * @op: required testing operator (=, !=, >, <, ...)
 * @rulestr: smack label to be audited
 * @vrule: pointer to save our own audit rule representation
 *
 * Prepare to audit cases where (@field @op @rulestr) is true.
 * The label to be audited is created if necessay.
 */
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
      char **rule = (char **)vrule;
      *rule = NULL;

      if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
            return -EINVAL;

      if (op != Audit_equal && op != Audit_not_equal)
            return -EINVAL;

      *rule = smk_import(rulestr, 0);

      return 0;
}

/**
 * smack_audit_rule_known - Distinguish Smack audit rules
 * @krule: rule of interest, in Audit kernel representation format
 *
 * This is used to filter Smack rules from remaining Audit ones.
 * If it's proved that this rule belongs to us, the
 * audit_rule_match hook will be called to do the final judgement.
 */
static int smack_audit_rule_known(struct audit_krule *krule)
{
      struct audit_field *f;
      int i;

      for (i = 0; i < krule->field_count; i++) {
            f = &krule->fields[i];

            if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
                  return 1;
      }

      return 0;
}

/**
 * smack_audit_rule_match - Audit given object ?
 * @secid: security id for identifying the object to test
 * @field: audit rule flags given from user-space
 * @op: required testing operator
 * @vrule: smack internal rule presentation
 * @actx: audit context associated with the check
 *
 * The core Audit hook. It's used to take the decision of
 * whether to audit or not to audit a given object.
 */
static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule,
                          struct audit_context *actx)
{
      char *smack;
      char *rule = vrule;

      if (!rule) {
            audit_log(actx, GFP_KERNEL, AUDIT_SELINUX_ERR,
                    "Smack: missing rule\n");
            return -ENOENT;
      }

      if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
            return 0;

      smack = smack_from_secid(secid);

      /*
       * No need to do string comparisons. If a match occurs,
       * both pointers will point to the same smack_known
       * label.
       */
      if (op == Audit_equal)
            return (rule == smack);
      if (op == Audit_not_equal)
            return (rule != smack);

      return 0;
}

/**
 * smack_audit_rule_free - free smack rule representation
 * @vrule: rule to be freed.
 *
 * No memory was allocated.
 */
static void smack_audit_rule_free(void *vrule)
{
      /* No-op */
}

#endif /* CONFIG_AUDIT */

/**
 * smack_secid_to_secctx - return the smack label for a secid
 * @secid: incoming integer
 * @secdata: destination
 * @seclen: how long it is
 *
 * Exists for networking code.
 */
static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
      char *sp = smack_from_secid(secid);

      *secdata = sp;
      *seclen = strlen(sp);
      return 0;
}

/**
 * smack_secctx_to_secid - return the secid for a smack label
 * @secdata: smack label
 * @seclen: how long result is
 * @secid: outgoing integer
 *
 * Exists for audit and networking code.
 */
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
      *secid = smack_to_secid(secdata);
      return 0;
}

/**
 * smack_release_secctx - don't do anything.
 * @secdata: unused
 * @seclen: unused
 *
 * Exists to make sure nothing gets done, and properly
 */
static void smack_release_secctx(char *secdata, u32 seclen)
{
}

struct security_operations smack_ops = {
      .name =                       "smack",

      .ptrace_may_access =          smack_ptrace_may_access,
      .ptrace_traceme =       smack_ptrace_traceme,
      .syslog =               smack_syslog,

      .sb_alloc_security =          smack_sb_alloc_security,
      .sb_free_security =           smack_sb_free_security,
      .sb_copy_data =         smack_sb_copy_data,
      .sb_kern_mount =        smack_sb_kern_mount,
      .sb_statfs =                  smack_sb_statfs,
      .sb_mount =                   smack_sb_mount,
      .sb_umount =                  smack_sb_umount,

      .inode_alloc_security =       smack_inode_alloc_security,
      .inode_free_security =        smack_inode_free_security,
      .inode_init_security =        smack_inode_init_security,
      .inode_link =                 smack_inode_link,
      .inode_unlink =         smack_inode_unlink,
      .inode_rmdir =                smack_inode_rmdir,
      .inode_rename =         smack_inode_rename,
      .inode_permission =           smack_inode_permission,
      .inode_setattr =        smack_inode_setattr,
      .inode_getattr =        smack_inode_getattr,
      .inode_setxattr =             smack_inode_setxattr,
      .inode_post_setxattr =        smack_inode_post_setxattr,
      .inode_getxattr =             smack_inode_getxattr,
      .inode_removexattr =          smack_inode_removexattr,
      .inode_getsecurity =          smack_inode_getsecurity,
      .inode_setsecurity =          smack_inode_setsecurity,
      .inode_listsecurity =         smack_inode_listsecurity,
      .inode_getsecid =       smack_inode_getsecid,

      .file_permission =            smack_file_permission,
      .file_alloc_security =        smack_file_alloc_security,
      .file_free_security =         smack_file_free_security,
      .file_ioctl =                 smack_file_ioctl,
      .file_lock =                  smack_file_lock,
      .file_fcntl =                 smack_file_fcntl,
      .file_set_fowner =            smack_file_set_fowner,
      .file_send_sigiotask =        smack_file_send_sigiotask,
      .file_receive =         smack_file_receive,

      .cred_free =                  smack_cred_free,
      .cred_prepare =               smack_cred_prepare,
      .cred_commit =                smack_cred_commit,
      .kernel_act_as =        smack_kernel_act_as,
      .kernel_create_files_as =     smack_kernel_create_files_as,
      .task_setpgid =         smack_task_setpgid,
      .task_getpgid =         smack_task_getpgid,
      .task_getsid =                smack_task_getsid,
      .task_getsecid =        smack_task_getsecid,
      .task_setnice =         smack_task_setnice,
      .task_setioprio =             smack_task_setioprio,
      .task_getioprio =             smack_task_getioprio,
      .task_setscheduler =          smack_task_setscheduler,
      .task_getscheduler =          smack_task_getscheduler,
      .task_movememory =            smack_task_movememory,
      .task_kill =                  smack_task_kill,
      .task_wait =                  smack_task_wait,
      .task_to_inode =        smack_task_to_inode,

      .ipc_permission =             smack_ipc_permission,
      .ipc_getsecid =               smack_ipc_getsecid,

      .msg_msg_alloc_security =     smack_msg_msg_alloc_security,
      .msg_msg_free_security =      smack_msg_msg_free_security,

      .msg_queue_alloc_security =   smack_msg_queue_alloc_security,
      .msg_queue_free_security =    smack_msg_queue_free_security,
      .msg_queue_associate =        smack_msg_queue_associate,
      .msg_queue_msgctl =           smack_msg_queue_msgctl,
      .msg_queue_msgsnd =           smack_msg_queue_msgsnd,
      .msg_queue_msgrcv =           smack_msg_queue_msgrcv,

      .shm_alloc_security =         smack_shm_alloc_security,
      .shm_free_security =          smack_shm_free_security,
      .shm_associate =        smack_shm_associate,
      .shm_shmctl =                 smack_shm_shmctl,
      .shm_shmat =                  smack_shm_shmat,

      .sem_alloc_security =         smack_sem_alloc_security,
      .sem_free_security =          smack_sem_free_security,
      .sem_associate =        smack_sem_associate,
      .sem_semctl =                 smack_sem_semctl,
      .sem_semop =                  smack_sem_semop,

      .d_instantiate =        smack_d_instantiate,

      .getprocattr =                smack_getprocattr,
      .setprocattr =                smack_setprocattr,

      .unix_stream_connect =        smack_unix_stream_connect,
      .unix_may_send =        smack_unix_may_send,

      .socket_post_create =         smack_socket_post_create,
      .socket_connect =       smack_socket_connect,
      .socket_sendmsg =       smack_socket_sendmsg,
      .socket_sock_rcv_skb =        smack_socket_sock_rcv_skb,
      .socket_getpeersec_stream =   smack_socket_getpeersec_stream,
      .socket_getpeersec_dgram =    smack_socket_getpeersec_dgram,
      .sk_alloc_security =          smack_sk_alloc_security,
      .sk_free_security =           smack_sk_free_security,
      .sock_graft =                 smack_sock_graft,
      .inet_conn_request =          smack_inet_conn_request,
      .inet_csk_clone =       smack_inet_csk_clone,

 /* key management security hooks */
#ifdef CONFIG_KEYS
      .key_alloc =                  smack_key_alloc,
      .key_free =                   smack_key_free,
      .key_permission =             smack_key_permission,
#endif /* CONFIG_KEYS */

 /* Audit hooks */
#ifdef CONFIG_AUDIT
      .audit_rule_init =            smack_audit_rule_init,
      .audit_rule_known =           smack_audit_rule_known,
      .audit_rule_match =           smack_audit_rule_match,
      .audit_rule_free =            smack_audit_rule_free,
#endif /* CONFIG_AUDIT */

      .secid_to_secctx =            smack_secid_to_secctx,
      .secctx_to_secid =            smack_secctx_to_secid,
      .release_secctx =             smack_release_secctx,
};


static __init void init_smack_know_list(void)
{
      list_add(&smack_known_huh.list, &smack_known_list);
      list_add(&smack_known_hat.list, &smack_known_list);
      list_add(&smack_known_star.list, &smack_known_list);
      list_add(&smack_known_floor.list, &smack_known_list);
      list_add(&smack_known_invalid.list, &smack_known_list);
      list_add(&smack_known_web.list, &smack_known_list);
}

/**
 * smack_init - initialize the smack system
 *
 * Returns 0
 */
static __init int smack_init(void)
{
      struct cred *cred;

      if (!security_module_enable(&smack_ops))
            return 0;

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

      /*
       * Set the security state for the initial task.
       */
      cred = (struct cred *) current->cred;
      cred->security = &smack_known_floor.smk_known;

      /* initilize the smack_know_list */
      init_smack_know_list();
      /*
       * Initialize locks
       */
      spin_lock_init(&smack_known_huh.smk_cipsolock);
      spin_lock_init(&smack_known_hat.smk_cipsolock);
      spin_lock_init(&smack_known_star.smk_cipsolock);
      spin_lock_init(&smack_known_floor.smk_cipsolock);
      spin_lock_init(&smack_known_invalid.smk_cipsolock);

      /*
       * Register with LSM
       */
      if (register_security(&smack_ops))
            panic("smack: Unable to register with kernel.\n");

      return 0;
}

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

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