/*
   *  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/kd.h>
  #include <asm/ioctls.h>

  #include <linux/ip.h>

  #include <linux/tcp.h>
  #include <linux/udp.h>

  #include <linux/slab.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 <linux/magic.h>

  #include "smack.h"

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

  /**
   * 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_access_check - 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_access_check(struct task_struct *ctp, unsigned int mode)

  {
  	int rc;

  	struct smk_audit_info ad;
  	char *sp, *tsp;

  	rc = cap_ptrace_access_check(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, bool from_file)

  {
  	int rc;

  	char *sp = current_security();

  	rc = cap_syslog(type, from_file);

  	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_root);

  	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;

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

  	/*
  	 * 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_alloc_blank - "allocate" blank task-level security credentials
   * @new: the new credentials
   * @gfp: the atomicity of any memory allocations
   *
   * Prepare a blank set of credentials for modification.  This must allocate all
   * the memory the LSM module might require such that cred_transfer() can
   * complete without error.
   */
  static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
  {
  	cred->security = NULL;
  	return 0;
  }
  
  
  /**

   * 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_transfer - Transfer the old credentials to the new credentials
   * @new: the new credentials
   * @old: the original credentials
   *
   * Fill in a set of blank credentials from another set of credentials.
   */
  static void smack_cred_transfer(struct cred *new, const struct cred *old)
  {
  	new->security = old->security;
  }
  
  /**

   * 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;

  		nsp->smk_flags |= SMK_INODE_INSTANT;

  		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.
  ",
  			       __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: dentry where inode will be attached

   * @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.
  		 */

  		dp = dget(opt_dentry);

  		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 != AF_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->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->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
  ");
  		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)
  {
  }

  static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
  {
  	return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0);
  }
  
  static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
  {
  	return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
  }
  
  static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
  {
  	int len = 0;
  	len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true);
  
  	if (len < 0)
  		return len;
  	*ctxlen = len;
  	return 0;
  }

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

  	.ptrace_access_check =		smack_ptrace_access_check,

  	.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_alloc_blank =		smack_cred_alloc_blank,

  	.cred_free =			smack_cred_free,

  	.cred_prepare =			smack_cred_prepare,

  	.cred_transfer =		smack_cred_transfer,

  	.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,

  	.inode_notifysecctx =		smack_inode_notifysecctx,
  	.inode_setsecctx =		smack_inode_setsecctx,
  	.inode_getsecctx =		smack_inode_getsecctx,

  };

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

  	cred = (struct cred *) current->cred;
  	cred->security = &smack_known_floor.smk_known;

  	/* initialize 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.
  ");
  
  	return 0;
  }
  
  /*
   * Smack requires early initialization in order to label
   * all processes and objects when they are created.
   */
  security_initcall(smack_init);