security/smack/smack_access.c - kernel/windcharger - Git at Google

 /*
  * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
  *
  *      This program is free software; you can redistribute it and/or modify
  *      it under the terms of the GNU General Public License as published by
  *      the Free Software Foundation, version 2.
  *
  * Author:
  *      Casey Schaufler <casey@schaufler-ca.com>
  *
  */

 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
 #include "smack.h"

 struct smack_known smack_known_huh = {
 	.smk_known	= "?",
 	.smk_secid	= 2,
 	.smk_cipso	= NULL,
 };

 struct smack_known smack_known_hat = {
 	.smk_known	= "^",
 	.smk_secid	= 3,
 	.smk_cipso	= NULL,
 };

 struct smack_known smack_known_star = {
 	.smk_known	= "*",
 	.smk_secid	= 4,
 	.smk_cipso	= NULL,
 };

 struct smack_known smack_known_floor = {
 	.smk_known	= "_",
 	.smk_secid	= 5,
 	.smk_cipso	= NULL,
 };

 struct smack_known smack_known_invalid = {
 	.smk_known	= "",
 	.smk_secid	= 6,
 	.smk_cipso	= NULL,
 };

 struct smack_known smack_known_web = {
 	.smk_known	= "@",
 	.smk_secid	= 7,
 	.smk_cipso	= NULL,
 };

 LIST_HEAD(smack_known_list);

 /*
  * The initial value needs to be bigger than any of the
  * known values above.
  */
 static u32 smack_next_secid = 10;

 /*
  * what events do we log
  * can be overwritten at run-time by /smack/logging
  */
 int log_policy = SMACK_AUDIT_DENIED;

 /**
  * smk_access_entry - look up matching access rule
  * @subject_label: a pointer to the subject's Smack label
  * @object_label: a pointer to the object's Smack label
  * @rule_list: the list of rules to search
  *
  * This function looks up the subject/object pair in the
  * access rule list and returns the access mode. If no
  * entry is found returns -ENOENT.
  *
  * NOTE:
  *
  * Earlier versions of this function allowed for labels that
  * were not on the label list. This was done to allow for
  * labels to come over the network that had never been seen
  * before on this host. Unless the receiving socket has the
  * star label this will always result in a failure check. The
  * star labeled socket case is now handled in the networking
  * hooks so there is no case where the label is not on the
  * label list. Checking to see if the address of two labels
  * is the same is now a reliable test.
  *
  * Do the object check first because that is more
  * likely to differ.
  */
 int smk_access_entry(char *subject_label, char *object_label,
 			struct list_head *rule_list)
 {
 	int may = -ENOENT;
 	struct smack_rule *srp;

 	list_for_each_entry_rcu(srp, rule_list, list) {
 		if (srp->smk_object == object_label &&
 		    srp->smk_subject == subject_label) {
 			may = srp->smk_access;
 			break;
 		}
 	}

 	return may;
 }

 /**
  * smk_access - determine if a subject has a specific access to an object
  * @subject_label: a pointer to the subject's Smack label
  * @object_label: a pointer to the object's Smack label
  * @request: the access requested, in "MAY" format
  * @a : a pointer to the audit data
  *
  * This function looks up the subject/object pair in the
  * access rule list and returns 0 if the access is permitted,
  * non zero otherwise.
  *
  * Smack labels are shared on smack_list
  */
 int smk_access(char *subject_label, char *object_label, int request,
 	       struct smk_audit_info *a)
 {
 	struct smack_known *skp;
 	int may = MAY_NOT;
 	int rc = 0;

 	/*
 	 * Hardcoded comparisons.
 	 *
 	 * A star subject can't access any object.
 	 */
 	if (subject_label == smack_known_star.smk_known) {
 		rc = -EACCES;
 		goto out_audit;
 	}
 	/*
 	 * An internet object can be accessed by any subject.
 	 * Tasks cannot be assigned the internet label.
 	 * An internet subject can access any object.
 	 */
 	if (object_label == smack_known_web.smk_known ||
 	    subject_label == smack_known_web.smk_known)
 		goto out_audit;
 	/*
 	 * A star object can be accessed by any subject.
 	 */
 	if (object_label == smack_known_star.smk_known)
 		goto out_audit;
 	/*
 	 * An object can be accessed in any way by a subject
 	 * with the same label.
 	 */
 	if (subject_label == object_label)
 		goto out_audit;
 	/*
 	 * A hat subject can read any object.
 	 * A floor object can be read by any subject.
 	 */
 	if ((request & MAY_ANYREAD) == request) {
 		if (object_label == smack_known_floor.smk_known)
 			goto out_audit;
 		if (subject_label == smack_known_hat.smk_known)
 			goto out_audit;
 	}
 	/*
 	 * Beyond here an explicit relationship is required.
 	 * If the requested access is contained in the available
 	 * access (e.g. read is included in readwrite) it's
 	 * good. A negative response from smk_access_entry()
 	 * indicates there is no entry for this pair.
 	 */
 	skp = smk_find_entry(subject_label);
 	rcu_read_lock();
 	may = smk_access_entry(subject_label, object_label, &skp->smk_rules);
 	rcu_read_unlock();

 	if (may > 0 && (request & may) == request)
 		goto out_audit;

 	rc = -EACCES;
 out_audit:
 #ifdef CONFIG_AUDIT
 	if (a)
 		smack_log(subject_label, object_label, request, rc, a);
 #endif
 	return rc;
 }

 /**
  * smk_curacc - determine if current has a specific access to an object
  * @obj_label: a pointer to the object's Smack label
  * @mode: the access requested, in "MAY" format
  * @a : common audit data
  *
  * This function checks the current subject label/object label pair
  * in the access rule list and returns 0 if the access is permitted,
  * non zero otherwise. It allows that current may have the capability
  * to override the rules.
  */
 int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
 {
 	struct task_smack *tsp = current_security();
 	char *sp = smk_of_task(tsp);
 	int may;
 	int rc;

 	/*
 	 * Check the global rule list
 	 */
 	rc = smk_access(sp, obj_label, mode, NULL);
 	if (rc == 0) {
 		/*
 		 * If there is an entry in the task's rule list
 		 * it can further restrict access.
 		 */
 		may = smk_access_entry(sp, obj_label, &tsp->smk_rules);
 		if (may < 0)
 			goto out_audit;
 		if ((mode & may) == mode)
 			goto out_audit;
 		rc = -EACCES;
 	}

 	/*
 	 * Return if a specific label has been designated as the
 	 * only one that gets privilege and current does not
 	 * have that label.
 	 */
 	if (smack_onlycap != NULL && smack_onlycap != sp)
 		goto out_audit;

 	if (capable(CAP_MAC_OVERRIDE))
 		rc = 0;

 out_audit:
 #ifdef CONFIG_AUDIT
 	if (a)
 		smack_log(sp, obj_label, mode, rc, a);
 #endif
 	return rc;
 }

 #ifdef CONFIG_AUDIT
 /**
  * smack_str_from_perm : helper to transalate an int to a
  * readable string
  * @string : the string to fill
  * @access : the int
  *
  */
 static inline void smack_str_from_perm(char *string, int access)
 {
 	int i = 0;
 	if (access & MAY_READ)
 		string[i++] = 'r';
 	if (access & MAY_WRITE)
 		string[i++] = 'w';
 	if (access & MAY_EXEC)
 		string[i++] = 'x';
 	if (access & MAY_APPEND)
 		string[i++] = 'a';
 	string[i] = '\0';
 }
 /**
  * smack_log_callback - SMACK specific information
  * will be called by generic audit code
  * @ab : the audit_buffer
  * @a  : audit_data
  *
  */
 static void smack_log_callback(struct audit_buffer *ab, void *a)
 {
 	struct common_audit_data *ad = a;
 	struct smack_audit_data *sad = &ad->smack_audit_data;
 	audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
 			 ad->smack_audit_data.function,
 			 sad->result ? "denied" : "granted");
 	audit_log_format(ab, " subject=");
 	audit_log_untrustedstring(ab, sad->subject);
 	audit_log_format(ab, " object=");
 	audit_log_untrustedstring(ab, sad->object);
 	audit_log_format(ab, " requested=%s", sad->request);
 }

 /**
  *  smack_log - Audit the granting or denial of permissions.
  *  @subject_label : smack label of the requester
  *  @object_label  : smack label of the object being accessed
  *  @request: requested permissions
  *  @result: result from smk_access
  *  @a:  auxiliary audit data
  *
  * Audit the granting or denial of permissions in accordance
  * with the policy.
  */
 void smack_log(char *subject_label, char *object_label, int request,
 	       int result, struct smk_audit_info *ad)
 {
 	char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
 	struct smack_audit_data *sad;
 	struct common_audit_data *a = &ad->a;

 	/* check if we have to log the current event */
 	if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
 		return;
 	if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
 		return;

 	if (a->smack_audit_data.function == NULL)
 		a->smack_audit_data.function = "unknown";

 	/* end preparing the audit data */
 	sad = &a->smack_audit_data;
 	smack_str_from_perm(request_buffer, request);
 	sad->subject = subject_label;
 	sad->object  = object_label;
 	sad->request = request_buffer;
 	sad->result  = result;
 	a->lsm_pre_audit = smack_log_callback;

 	common_lsm_audit(a);
 }
 #else /* #ifdef CONFIG_AUDIT */
 void smack_log(char *subject_label, char *object_label, int request,
                int result, struct smk_audit_info *ad)
 {
 }
 #endif

 static DEFINE_MUTEX(smack_known_lock);

 /**
  * smk_find_entry - find a label on the list, return the list entry
  * @string: a text string that might be a Smack label
  *
  * Returns a pointer to the entry in the label list that
  * matches the passed string.
  */
 struct smack_known *smk_find_entry(const char *string)
 {
 	struct smack_known *skp;

 	list_for_each_entry_rcu(skp, &smack_known_list, list) {
 		if (strncmp(skp->smk_known, string, SMK_MAXLEN) == 0)
 			return skp;
 	}

 	return NULL;
 }

 /**
  * smk_parse_smack - parse smack label from a text string
  * @string: a text string that might contain a Smack label
  * @len: the maximum size, or zero if it is NULL terminated.
  * @smack: parsed smack label, or NULL if parse error
  */
 void smk_parse_smack(const char *string, int len, char *smack)
 {
 	int found;
 	int i;

 	if (len <= 0 || len > SMK_MAXLEN)
 		len = SMK_MAXLEN;

 	for (i = 0, found = 0; i < SMK_LABELLEN; i++) {
 		if (found)
 			smack[i] = '\0';
 		else if (i >= len || string[i] > '~' || string[i] <= ' ' ||
 			 string[i] == '/' || string[i] == '"' ||
 			 string[i] == '\\' || string[i] == '\'') {
 			smack[i] = '\0';
 			found = 1;
 		} else
 			smack[i] = string[i];
 	}
 }

 /**
  * smk_import_entry - import a label, return the list entry
  * @string: a text string that might be a Smack label
  * @len: the maximum size, or zero if it is NULL terminated.
  *
  * Returns a pointer to the entry in the label list that
  * matches the passed string, adding it if necessary.
  */
 struct smack_known *smk_import_entry(const char *string, int len)
 {
 	struct smack_known *skp;
 	char smack[SMK_LABELLEN];

 	smk_parse_smack(string, len, smack);
 	if (smack[0] == '\0')
 		return NULL;

 	mutex_lock(&smack_known_lock);

 	skp = smk_find_entry(smack);

 	if (skp == NULL) {
 		skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
 		if (skp != NULL) {
 			strncpy(skp->smk_known, smack, SMK_MAXLEN);
 			skp->smk_secid = smack_next_secid++;
 			skp->smk_cipso = NULL;
 			INIT_LIST_HEAD(&skp->smk_rules);
 			spin_lock_init(&skp->smk_cipsolock);
 			mutex_init(&skp->smk_rules_lock);
 			/*
 			 * Make sure that the entry is actually
 			 * filled before putting it on the list.
 			 */
 			list_add_rcu(&skp->list, &smack_known_list);
 		}
 	}

 	mutex_unlock(&smack_known_lock);

 	return skp;
 }

 /**
  * smk_import - import a smack label
  * @string: a text string that might be a Smack label
  * @len: the maximum size, or zero if it is NULL terminated.
  *
  * Returns a pointer to the label in the label list that
  * matches the passed string, adding it if necessary.
  */
 char *smk_import(const char *string, int len)
 {
 	struct smack_known *skp;

 	/* labels cannot begin with a '-' */
 	if (string[0] == '-')
 		return NULL;
 	skp = smk_import_entry(string, len);
 	if (skp == NULL)
 		return NULL;
 	return skp->smk_known;
 }

 /**
  * smack_from_secid - find the Smack label associated with a secid
  * @secid: an integer that might be associated with a Smack label
  *
  * Returns a pointer to the appropriate Smack label if there is one,
  * otherwise a pointer to the invalid Smack label.
  */
 char *smack_from_secid(const u32 secid)
 {
 	struct smack_known *skp;

 	rcu_read_lock();
 	list_for_each_entry_rcu(skp, &smack_known_list, list) {
 		if (skp->smk_secid == secid) {
 			rcu_read_unlock();
 			return skp->smk_known;
 		}
 	}

 	/*
 	 * If we got this far someone asked for the translation
 	 * of a secid that is not on the list.
 	 */
 	rcu_read_unlock();
 	return smack_known_invalid.smk_known;
 }

 /**
  * smack_to_secid - find the secid associated with a Smack label
  * @smack: the Smack label
  *
  * Returns the appropriate secid if there is one,
  * otherwise 0
  */
 u32 smack_to_secid(const char *smack)
 {
 	struct smack_known *skp;

 	rcu_read_lock();
 	list_for_each_entry_rcu(skp, &smack_known_list, list) {
 		if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
 			rcu_read_unlock();
 			return skp->smk_secid;
 		}
 	}
 	rcu_read_unlock();
 	return 0;
 }

 /**
  * smack_from_cipso - find the Smack label associated with a CIPSO option
  * @level: Bell & LaPadula level from the network
  * @cp: Bell & LaPadula categories from the network
  *
  * This is a simple lookup in the label table.
  *
  * Return the matching label from the label list or NULL.
  */
 char *smack_from_cipso(u32 level, char *cp)
 {
 	struct smack_known *kp;
 	char *final = NULL;

 	rcu_read_lock();
 	list_for_each_entry(kp, &smack_known_list, list) {
 		if (kp->smk_cipso == NULL)
 			continue;

 		spin_lock_bh(&kp->smk_cipsolock);

 		if (kp->smk_cipso->smk_level == level &&
 		    memcmp(kp->smk_cipso->smk_catset, cp, SMK_LABELLEN) == 0)
 			final = kp->smk_known;

 		spin_unlock_bh(&kp->smk_cipsolock);

 		if (final != NULL)
 			break;
 	}
 	rcu_read_unlock();

 	return final;
 }

 /**
  * smack_to_cipso - find the CIPSO option to go with a Smack label
  * @smack: a pointer to the smack label in question
  * @cp: where to put the result
  *
  * Returns zero if a value is available, non-zero otherwise.
  */
 int smack_to_cipso(const char *smack, struct smack_cipso *cp)
 {
 	struct smack_known *kp;
 	int found = 0;

 	rcu_read_lock();
 	list_for_each_entry_rcu(kp, &smack_known_list, list) {
 		if (kp->smk_known == smack ||
 		    strcmp(kp->smk_known, smack) == 0) {
 			found = 1;
 			break;
 		}
 	}
 	rcu_read_unlock();

 	if (found == 0 || kp->smk_cipso == NULL)
 		return -ENOENT;

 	memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));
 	return 0;
 }
	/*
	* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, version 2.
	*
	* Author:
	* Casey Schaufler <casey@schaufler-ca.com>
	*
	*/

	#include <linux/types.h>
	#include <linux/slab.h>
	#include <linux/fs.h>
	#include <linux/sched.h>
	#include "smack.h"

	struct smack_known smack_known_huh = {
	.smk_known = "?",
	.smk_secid = 2,
	.smk_cipso = NULL,
	};

	struct smack_known smack_known_hat = {
	.smk_known = "^",
	.smk_secid = 3,
	.smk_cipso = NULL,
	};

	struct smack_known smack_known_star = {
	.smk_known = "*",
	.smk_secid = 4,
	.smk_cipso = NULL,
	};

	struct smack_known smack_known_floor = {
	.smk_known = "_",
	.smk_secid = 5,
	.smk_cipso = NULL,
	};

	struct smack_known smack_known_invalid = {
	.smk_known = "",
	.smk_secid = 6,
	.smk_cipso = NULL,
	};

	struct smack_known smack_known_web = {
	.smk_known = "@",
	.smk_secid = 7,
	.smk_cipso = NULL,
	};

	LIST_HEAD(smack_known_list);

	/*
	* The initial value needs to be bigger than any of the
	* known values above.
	*/
	static u32 smack_next_secid = 10;

	/*
	* what events do we log
	* can be overwritten at run-time by /smack/logging
	*/
	int log_policy = SMACK_AUDIT_DENIED;

	/**
	* smk_access_entry - look up matching access rule
	* @subject_label: a pointer to the subject's Smack label
	* @object_label: a pointer to the object's Smack label
	* @rule_list: the list of rules to search
	*
	* This function looks up the subject/object pair in the
	* access rule list and returns the access mode. If no
	* entry is found returns -ENOENT.
	*
	* NOTE:
	*
	* Earlier versions of this function allowed for labels that
	* were not on the label list. This was done to allow for
	* labels to come over the network that had never been seen
	* before on this host. Unless the receiving socket has the
	* star label this will always result in a failure check. The
	* star labeled socket case is now handled in the networking
	* hooks so there is no case where the label is not on the
	* label list. Checking to see if the address of two labels
	* is the same is now a reliable test.
	*
	* Do the object check first because that is more
	* likely to differ.
	*/
	int smk_access_entry(char subject_label, char object_label,
	struct list_head *rule_list)
	{
	int may = -ENOENT;
	struct smack_rule *srp;

	list_for_each_entry_rcu(srp, rule_list, list) {
	if (srp->smk_object == object_label &&
	srp->smk_subject == subject_label) {
	may = srp->smk_access;
	break;
	}
	}

	return may;
	}

	/**
	* smk_access - determine if a subject has a specific access to an object
	* @subject_label: a pointer to the subject's Smack label
	* @object_label: a pointer to the object's Smack label
	* @request: the access requested, in "MAY" format
	* @a : a pointer to the audit data
	*
	* This function looks up the subject/object pair in the
	* access rule list and returns 0 if the access is permitted,
	* non zero otherwise.
	*
	* Smack labels are shared on smack_list
	*/
	int smk_access(char subject_label, char object_label, int request,
	struct smk_audit_info *a)
	{
	struct smack_known *skp;
	int may = MAY_NOT;
	int rc = 0;

	/*
	* Hardcoded comparisons.
	*
	* A star subject can't access any object.
	*/
	if (subject_label == smack_known_star.smk_known) {
	rc = -EACCES;
	goto out_audit;
	}
	/*
	* An internet object can be accessed by any subject.
	* Tasks cannot be assigned the internet label.
	* An internet subject can access any object.
	*/
	if (object_label == smack_known_web.smk_known \|\|
	subject_label == smack_known_web.smk_known)
	goto out_audit;
	/*
	* A star object can be accessed by any subject.
	*/
	if (object_label == smack_known_star.smk_known)
	goto out_audit;
	/*
	* An object can be accessed in any way by a subject
	* with the same label.
	*/
	if (subject_label == object_label)
	goto out_audit;
	/*
	* A hat subject can read any object.
	* A floor object can be read by any subject.
	*/
	if ((request & MAY_ANYREAD) == request) {
	if (object_label == smack_known_floor.smk_known)
	goto out_audit;
	if (subject_label == smack_known_hat.smk_known)
	goto out_audit;
	}
	/*
	* Beyond here an explicit relationship is required.
	* If the requested access is contained in the available
	* access (e.g. read is included in readwrite) it's
	* good. A negative response from smk_access_entry()
	* indicates there is no entry for this pair.
	*/
	skp = smk_find_entry(subject_label);
	rcu_read_lock();
	may = smk_access_entry(subject_label, object_label, &skp->smk_rules);
	rcu_read_unlock();

	if (may > 0 && (request & may) == request)
	goto out_audit;

	rc = -EACCES;
	out_audit:
	#ifdef CONFIG_AUDIT
	if (a)
	smack_log(subject_label, object_label, request, rc, a);
	#endif
	return rc;
	}

	/**
	* smk_curacc - determine if current has a specific access to an object
	* @obj_label: a pointer to the object's Smack label
	* @mode: the access requested, in "MAY" format
	* @a : common audit data
	*
	* This function checks the current subject label/object label pair
	* in the access rule list and returns 0 if the access is permitted,
	* non zero otherwise. It allows that current may have the capability
	* to override the rules.
	*/
	int smk_curacc(char obj_label, u32 mode, struct smk_audit_info a)
	{
	struct task_smack *tsp = current_security();
	char *sp = smk_of_task(tsp);
	int may;
	int rc;

	/*
	* Check the global rule list
	*/
	rc = smk_access(sp, obj_label, mode, NULL);
	if (rc == 0) {
	/*
	* If there is an entry in the task's rule list
	* it can further restrict access.
	*/
	may = smk_access_entry(sp, obj_label, &tsp->smk_rules);
	if (may < 0)
	goto out_audit;
	if ((mode & may) == mode)
	goto out_audit;
	rc = -EACCES;
	}

	/*
	* Return if a specific label has been designated as the
	* only one that gets privilege and current does not
	* have that label.
	*/
	if (smack_onlycap != NULL && smack_onlycap != sp)
	goto out_audit;

	if (capable(CAP_MAC_OVERRIDE))
	rc = 0;

	out_audit:
	#ifdef CONFIG_AUDIT
	if (a)
	smack_log(sp, obj_label, mode, rc, a);
	#endif
	return rc;
	}

	#ifdef CONFIG_AUDIT
	/**
	* smack_str_from_perm : helper to transalate an int to a
	* readable string
	* @string : the string to fill
	* @access : the int
	*
	*/
	static inline void smack_str_from_perm(char *string, int access)
	{
	int i = 0;
	if (access & MAY_READ)
	string[i++] = 'r';
	if (access & MAY_WRITE)
	string[i++] = 'w';
	if (access & MAY_EXEC)
	string[i++] = 'x';
	if (access & MAY_APPEND)
	string[i++] = 'a';
	string[i] = '\0';
	}
	/**
	* smack_log_callback - SMACK specific information
	* will be called by generic audit code
	* @ab : the audit_buffer
	* @a : audit_data
	*
	*/
	static void smack_log_callback(struct audit_buffer ab, void a)
	{
	struct common_audit_data *ad = a;
	struct smack_audit_data *sad = &ad->smack_audit_data;
	audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
	ad->smack_audit_data.function,
	sad->result ? "denied" : "granted");
	audit_log_format(ab, " subject=");
	audit_log_untrustedstring(ab, sad->subject);
	audit_log_format(ab, " object=");
	audit_log_untrustedstring(ab, sad->object);
	audit_log_format(ab, " requested=%s", sad->request);
	}

	/**
	* smack_log - Audit the granting or denial of permissions.
	* @subject_label : smack label of the requester
	* @object_label : smack label of the object being accessed
	* @request: requested permissions
	* @result: result from smk_access
	* @a: auxiliary audit data
	*
	* Audit the granting or denial of permissions in accordance
	* with the policy.
	*/
	void smack_log(char subject_label, char object_label, int request,
	int result, struct smk_audit_info *ad)
	{
	char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
	struct smack_audit_data *sad;
	struct common_audit_data *a = &ad->a;

	/* check if we have to log the current event */
	if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
	return;
	if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
	return;

	if (a->smack_audit_data.function == NULL)
	a->smack_audit_data.function = "unknown";

	/* end preparing the audit data */
	sad = &a->smack_audit_data;
	smack_str_from_perm(request_buffer, request);
	sad->subject = subject_label;
	sad->object = object_label;
	sad->request = request_buffer;
	sad->result = result;
	a->lsm_pre_audit = smack_log_callback;

	common_lsm_audit(a);
	}
	#else /* #ifdef CONFIG_AUDIT */
	void smack_log(char subject_label, char object_label, int request,
	int result, struct smk_audit_info *ad)
	{
	}
	#endif

	static DEFINE_MUTEX(smack_known_lock);

	/**
	* smk_find_entry - find a label on the list, return the list entry
	* @string: a text string that might be a Smack label
	*
	* Returns a pointer to the entry in the label list that
	* matches the passed string.
	*/
	struct smack_known smk_find_entry(const char string)
	{
	struct smack_known *skp;

	list_for_each_entry_rcu(skp, &smack_known_list, list) {
	if (strncmp(skp->smk_known, string, SMK_MAXLEN) == 0)
	return skp;
	}

	return NULL;
	}

	/**
	* smk_parse_smack - parse smack label from a text string
	* @string: a text string that might contain a Smack label
	* @len: the maximum size, or zero if it is NULL terminated.
	* @smack: parsed smack label, or NULL if parse error
	*/
	void smk_parse_smack(const char string, int len, char smack)
	{
	int found;
	int i;

	if (len <= 0 \|\| len > SMK_MAXLEN)
	len = SMK_MAXLEN;

	for (i = 0, found = 0; i < SMK_LABELLEN; i++) {
	if (found)
	smack[i] = '\0';
	else if (i >= len \|\| string[i] > '~' \|\| string[i] <= ' ' \|\|
	string[i] == '/' \|\| string[i] == '"' \|\|
	string[i] == '\\' \|\| string[i] == '\'') {
	smack[i] = '\0';
	found = 1;
	} else
	smack[i] = string[i];
	}
	}

	/**
	* smk_import_entry - import a label, return the list entry
	* @string: a text string that might be a Smack label
	* @len: the maximum size, or zero if it is NULL terminated.
	*
	* Returns a pointer to the entry in the label list that
	* matches the passed string, adding it if necessary.
	*/
	struct smack_known smk_import_entry(const char string, int len)
	{
	struct smack_known *skp;
	char smack[SMK_LABELLEN];

	smk_parse_smack(string, len, smack);
	if (smack[0] == '\0')
	return NULL;

	mutex_lock(&smack_known_lock);

	skp = smk_find_entry(smack);

	if (skp == NULL) {
	skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
	if (skp != NULL) {
	strncpy(skp->smk_known, smack, SMK_MAXLEN);
	skp->smk_secid = smack_next_secid++;
	skp->smk_cipso = NULL;
	INIT_LIST_HEAD(&skp->smk_rules);
	spin_lock_init(&skp->smk_cipsolock);
	mutex_init(&skp->smk_rules_lock);
	/*
	* Make sure that the entry is actually
	* filled before putting it on the list.
	*/
	list_add_rcu(&skp->list, &smack_known_list);
	}
	}

	mutex_unlock(&smack_known_lock);

	return skp;
	}

	/**
	* smk_import - import a smack label
	* @string: a text string that might be a Smack label
	* @len: the maximum size, or zero if it is NULL terminated.
	*
	* Returns a pointer to the label in the label list that
	* matches the passed string, adding it if necessary.
	*/
	char smk_import(const char string, int len)
	{
	struct smack_known *skp;

	/* labels cannot begin with a '-' */
	if (string[0] == '-')
	return NULL;
	skp = smk_import_entry(string, len);
	if (skp == NULL)
	return NULL;
	return skp->smk_known;
	}

	/**
	* smack_from_secid - find the Smack label associated with a secid
	* @secid: an integer that might be associated with a Smack label
	*
	* Returns a pointer to the appropriate Smack label if there is one,
	* otherwise a pointer to the invalid Smack label.
	*/
	char *smack_from_secid(const u32 secid)
	{
	struct smack_known *skp;

	rcu_read_lock();
	list_for_each_entry_rcu(skp, &smack_known_list, list) {
	if (skp->smk_secid == secid) {
	rcu_read_unlock();
	return skp->smk_known;
	}
	}

	/*
	* If we got this far someone asked for the translation
	* of a secid that is not on the list.
	*/
	rcu_read_unlock();
	return smack_known_invalid.smk_known;
	}

	/**
	* smack_to_secid - find the secid associated with a Smack label
	* @smack: the Smack label
	*
	* Returns the appropriate secid if there is one,
	* otherwise 0
	*/
	u32 smack_to_secid(const char *smack)
	{
	struct smack_known *skp;

	rcu_read_lock();
	list_for_each_entry_rcu(skp, &smack_known_list, list) {
	if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
	rcu_read_unlock();
	return skp->smk_secid;
	}
	}
	rcu_read_unlock();
	return 0;
	}

	/**
	* smack_from_cipso - find the Smack label associated with a CIPSO option
	* @level: Bell & LaPadula level from the network
	* @cp: Bell & LaPadula categories from the network
	*
	* This is a simple lookup in the label table.
	*
	* Return the matching label from the label list or NULL.
	*/
	char smack_from_cipso(u32 level, char cp)
	{
	struct smack_known *kp;
	char *final = NULL;

	rcu_read_lock();
	list_for_each_entry(kp, &smack_known_list, list) {
	if (kp->smk_cipso == NULL)
	continue;

	spin_lock_bh(&kp->smk_cipsolock);

	if (kp->smk_cipso->smk_level == level &&
	memcmp(kp->smk_cipso->smk_catset, cp, SMK_LABELLEN) == 0)
	final = kp->smk_known;

	spin_unlock_bh(&kp->smk_cipsolock);

	if (final != NULL)
	break;
	}
	rcu_read_unlock();

	return final;
	}

	/**
	* smack_to_cipso - find the CIPSO option to go with a Smack label
	* @smack: a pointer to the smack label in question
	* @cp: where to put the result
	*
	* Returns zero if a value is available, non-zero otherwise.
	*/
	int smack_to_cipso(const char smack, struct smack_cipso cp)
	{
	struct smack_known *kp;
	int found = 0;

	rcu_read_lock();
	list_for_each_entry_rcu(kp, &smack_known_list, list) {
	if (kp->smk_known == smack \|\|
	strcmp(kp->smk_known, smack) == 0) {
	found = 1;
	break;
	}
	}
	rcu_read_unlock();

	if (found == 0 \|\| kp->smk_cipso == NULL)
	return -ENOENT;

	memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));
	return 0;
	}