text: /*
   * Copyright (C) 2008 IBM Corporation
   * Author: Mimi Zohar <zohar@us.ibm.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 of the License.
   *
   * ima_policy.c
   *	- initialize default measure policy rules
   *
   */
  #include <linux/module.h>
  #include <linux/list.h>
  #include <linux/security.h>
  #include <linux/magic.h>
  #include <linux/parser.h>
  #include <linux/slab.h>
  #include <linux/genhd.h>
  
  #include "ima.h"
  
  /* flags definitions */
  #define IMA_FUNC	0x0001
  #define IMA_MASK	0x0002
  #define IMA_FSMAGIC	0x0004
  #define IMA_UID		0x0008
  #define IMA_FOWNER	0x0010
  #define IMA_FSUUID	0x0020
  
  #define UNKNOWN		0
  #define MEASURE		0x0001	/* same as IMA_MEASURE */
  #define DONT_MEASURE	0x0002
  #define APPRAISE	0x0004	/* same as IMA_APPRAISE */
  #define DONT_APPRAISE	0x0008
  #define AUDIT		0x0040
  
  int ima_policy_flag;
  
  #define MAX_LSM_RULES 6
  enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  };
  
  struct ima_rule_entry {
  	struct list_head list;
  	int action;
  	unsigned int flags;
  	enum ima_hooks func;
  	int mask;
  	unsigned long fsmagic;
  	u8 fsuuid[16];
  	kuid_t uid;
  	kuid_t fowner;
  	struct {
  		void *rule;	/* LSM file metadata specific */
  		void *args_p;	/* audit value */
  		int type;	/* audit type */
  	} lsm[MAX_LSM_RULES];
  };
  
  /*
   * Without LSM specific knowledge, the default policy can only be
   * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
   */
  
  /*
   * The minimum rule set to allow for full TCB coverage.  Measures all files
   * opened or mmap for exec and everything read by root.  Dangerous because
   * normal users can easily run the machine out of memory simply building
   * and running executables.
   */
  static struct ima_rule_entry default_rules[] = {
  	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
  	 .flags = IMA_FUNC | IMA_MASK},
  	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
  	 .flags = IMA_FUNC | IMA_MASK},
  	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID,
  	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
  	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
  };
  
  static struct ima_rule_entry default_appraise_rules[] = {
  	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
  	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
  #else
  	/* force signature */
  	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
  	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
  #endif
  };
  
  static LIST_HEAD(ima_default_rules);
  static LIST_HEAD(ima_policy_rules);
  static struct list_head *ima_rules;
  
  static DEFINE_MUTEX(ima_rules_mutex);
  
  static bool ima_use_tcb __initdata;
  static int __init default_measure_policy_setup(char *str)
  {
  	ima_use_tcb = 1;
  	return 1;
  }
  __setup("ima_tcb", default_measure_policy_setup);
  
  static bool ima_use_appraise_tcb __initdata;
  static int __init default_appraise_policy_setup(char *str)
  {
  	ima_use_appraise_tcb = 1;
  	return 1;
  }
  __setup("ima_appraise_tcb", default_appraise_policy_setup);
  
  /*
   * Although the IMA policy does not change, the LSM policy can be
   * reloaded, leaving the IMA LSM based rules referring to the old,
   * stale LSM policy.
   *
   * Update the IMA LSM based rules to reflect the reloaded LSM policy.
   * We assume the rules still exist; and BUG_ON() if they don't.
   */
  static void ima_lsm_update_rules(void)
  {
  	struct ima_rule_entry *entry, *tmp;
  	int result;
  	int i;
  
  	mutex_lock(&ima_rules_mutex);
  	list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
  		for (i = 0; i < MAX_LSM_RULES; i++) {
  			if (!entry->lsm[i].rule)
  				continue;
  			result = security_filter_rule_init(entry->lsm[i].type,
  							   Audit_equal,
  							   entry->lsm[i].args_p,
  							   &entry->lsm[i].rule);
  			BUG_ON(!entry->lsm[i].rule);
  		}
  	}
  	mutex_unlock(&ima_rules_mutex);
  }
  
  /**
   * ima_match_rules - determine whether an inode matches the measure rule.
   * @rule: a pointer to a rule
   * @inode: a pointer to an inode
   * @func: LIM hook identifier
   * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
   *
   * Returns true on rule match, false on failure.
   */
  static bool ima_match_rules(struct ima_rule_entry *rule,
  			    struct inode *inode, enum ima_hooks func, int mask)
  {
  	struct task_struct *tsk = current;
  	const struct cred *cred = current_cred();
  	int i;
  
  	if ((rule->flags & IMA_FUNC) &&
  	    (rule->func != func && func != POST_SETATTR))
  		return false;
  	if ((rule->flags & IMA_MASK) &&
  	    (rule->mask != mask && func != POST_SETATTR))
  		return false;
  	if ((rule->flags & IMA_FSMAGIC)
  	    && rule->fsmagic != inode->i_sb->s_magic)
  		return false;
  	if ((rule->flags & IMA_FSUUID) &&
  	    memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
  		return false;
  	if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
  		return false;
  	if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
  		return false;
  	for (i = 0; i < MAX_LSM_RULES; i++) {
  		int rc = 0;
  		u32 osid, sid;
  		int retried = 0;
  
  		if (!rule->lsm[i].rule)
  			continue;
  retry:
  		switch (i) {
  		case LSM_OBJ_USER:
  		case LSM_OBJ_ROLE:
  		case LSM_OBJ_TYPE:
  			security_inode_getsecid(inode, &osid);
  			rc = security_filter_rule_match(osid,
  							rule->lsm[i].type,
  							Audit_equal,
  							rule->lsm[i].rule,
  							NULL);
  			break;
  		case LSM_SUBJ_USER:
  		case LSM_SUBJ_ROLE:
  		case LSM_SUBJ_TYPE:
  			security_task_getsecid(tsk, &sid);
  			rc = security_filter_rule_match(sid,
  							rule->lsm[i].type,
  							Audit_equal,
  							rule->lsm[i].rule,
  							NULL);
  		default:
  			break;
  		}
  		if ((rc < 0) && (!retried)) {
  			retried = 1;
  			ima_lsm_update_rules();
  			goto retry;
  		}
  		if (!rc)
  			return false;
  	}
  	return true;
  }
  
  /*
   * In addition to knowing that we need to appraise the file in general,
   * we need to differentiate between calling hooks, for hook specific rules.
   */
  static int get_subaction(struct ima_rule_entry *rule, int func)
  {
  	if (!(rule->flags & IMA_FUNC))
  		return IMA_FILE_APPRAISE;
  
  	switch (func) {
  	case MMAP_CHECK:
  		return IMA_MMAP_APPRAISE;
  	case BPRM_CHECK:
  		return IMA_BPRM_APPRAISE;
  	case MODULE_CHECK:
  		return IMA_MODULE_APPRAISE;
  	case FIRMWARE_CHECK:
  		return IMA_FIRMWARE_APPRAISE;
  	case FILE_CHECK:
  	default:
  		return IMA_FILE_APPRAISE;
  	}
  }
  
  /**
   * ima_match_policy - decision based on LSM and other conditions
   * @inode: pointer to an inode for which the policy decision is being made
   * @func: IMA hook identifier
   * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
   *
   * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
   * conditions.
   *
   * (There is no need for locking when walking the policy list,
   * as elements in the list are never deleted, nor does the list
   * change.)
   */
  int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
  		     int flags)
  {
  	struct ima_rule_entry *entry;
  	int action = 0, actmask = flags | (flags << 1);
  
  	list_for_each_entry(entry, ima_rules, list) {
  
  		if (!(entry->action & actmask))
  			continue;
  
  		if (!ima_match_rules(entry, inode, func, mask))
  			continue;
  
  		action |= entry->flags & IMA_ACTION_FLAGS;
  
  		action |= entry->action & IMA_DO_MASK;
  		if (entry->action & IMA_APPRAISE)
  			action |= get_subaction(entry, func);
  
  		if (entry->action & IMA_DO_MASK)
  			actmask &= ~(entry->action | entry->action << 1);
  		else
  			actmask &= ~(entry->action | entry->action >> 1);
  
  		if (!actmask)
  			break;
  	}
  
  	return action;
  }
  
  /*
   * Initialize the ima_policy_flag variable based on the currently
   * loaded policy.  Based on this flag, the decision to short circuit
   * out of a function or not call the function in the first place
   * can be made earlier.
   */
  void ima_update_policy_flag(void)
  {
  	struct ima_rule_entry *entry;
  
  	ima_policy_flag = 0;
  	list_for_each_entry(entry, ima_rules, list) {
  		if (entry->action & IMA_DO_MASK)
  			ima_policy_flag |= entry->action;
  	}
  
  	if (!ima_appraise)
  		ima_policy_flag &= ~IMA_APPRAISE;
  }
  
  /**
   * ima_init_policy - initialize the default measure rules.
   *
   * ima_rules points to either the ima_default_rules or the
   * the new ima_policy_rules.
   */
  void __init ima_init_policy(void)
  {
  	int i, measure_entries, appraise_entries;
  
  	/* if !ima_use_tcb set entries = 0 so we load NO default rules */
  	measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
  	appraise_entries = ima_use_appraise_tcb ?
  			 ARRAY_SIZE(default_appraise_rules) : 0;
  
  	for (i = 0; i < measure_entries + appraise_entries; i++) {
  		if (i < measure_entries)
  			list_add_tail(&default_rules[i].list,
  				      &ima_default_rules);
  		else {
  			int j = i - measure_entries;
  
  			list_add_tail(&default_appraise_rules[j].list,
  				      &ima_default_rules);
  		}
  	}
  
  	ima_rules = &ima_default_rules;
  }
  
  /**
   * ima_update_policy - update default_rules with new measure rules
   *
   * Called on file .release to update the default rules with a complete new
   * policy.  Once updated, the policy is locked, no additional rules can be
   * added to the policy.
   */
  void ima_update_policy(void)
  {
  	ima_rules = &ima_policy_rules;
  	ima_update_policy_flag();
  }
  
  enum {
  	Opt_err = -1,
  	Opt_measure = 1, Opt_dont_measure,
  	Opt_appraise, Opt_dont_appraise,
  	Opt_audit,
  	Opt_obj_user, Opt_obj_role, Opt_obj_type,
  	Opt_subj_user, Opt_subj_role, Opt_subj_type,
  	Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
  	Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
  };
  
  static match_table_t policy_tokens = {
  	{Opt_measure, "measure"},
  	{Opt_dont_measure, "dont_measure"},
  	{Opt_appraise, "appraise"},
  	{Opt_dont_appraise, "dont_appraise"},
  	{Opt_audit, "audit"},
  	{Opt_obj_user, "obj_user=%s"},
  	{Opt_obj_role, "obj_role=%s"},
  	{Opt_obj_type, "obj_type=%s"},
  	{Opt_subj_user, "subj_user=%s"},
  	{Opt_subj_role, "subj_role=%s"},
  	{Opt_subj_type, "subj_type=%s"},
  	{Opt_func, "func=%s"},
  	{Opt_mask, "mask=%s"},
  	{Opt_fsmagic, "fsmagic=%s"},
  	{Opt_fsuuid, "fsuuid=%s"},
  	{Opt_uid, "uid=%s"},
  	{Opt_fowner, "fowner=%s"},
  	{Opt_appraise_type, "appraise_type=%s"},
  	{Opt_permit_directio, "permit_directio"},
  	{Opt_err, NULL}
  };
  
  static int ima_lsm_rule_init(struct ima_rule_entry *entry,
  			     substring_t *args, int lsm_rule, int audit_type)
  {
  	int result;
  
  	if (entry->lsm[lsm_rule].rule)
  		return -EINVAL;
  
  	entry->lsm[lsm_rule].args_p = match_strdup(args);
  	if (!entry->lsm[lsm_rule].args_p)
  		return -ENOMEM;
  
  	entry->lsm[lsm_rule].type = audit_type;
  	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
  					   Audit_equal,
  					   entry->lsm[lsm_rule].args_p,
  					   &entry->lsm[lsm_rule].rule);
  	if (!entry->lsm[lsm_rule].rule) {
  		kfree(entry->lsm[lsm_rule].args_p);
  		return -EINVAL;
  	}
  
  	return result;
  }
  
  static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
  {
  	audit_log_format(ab, "%s=", key);
  	audit_log_untrustedstring(ab, value);
  	audit_log_format(ab, " ");
  }
  
  static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
  {
  	struct audit_buffer *ab;
  	char *p;
  	int result = 0;
  
  	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
  
  	entry->uid = INVALID_UID;
  	entry->fowner = INVALID_UID;
  	entry->action = UNKNOWN;
  	while ((p = strsep(&rule, " \t")) != NULL) {
  		substring_t args[MAX_OPT_ARGS];
  		int token;
  		unsigned long lnum;
  
  		if (result < 0)
  			break;
  		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
  			continue;
  		token = match_token(p, policy_tokens, args);
  		switch (token) {
  		case Opt_measure:
  			ima_log_string(ab, "action", "measure");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = MEASURE;
  			break;
  		case Opt_dont_measure:
  			ima_log_string(ab, "action", "dont_measure");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = DONT_MEASURE;
  			break;
  		case Opt_appraise:
  			ima_log_string(ab, "action", "appraise");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = APPRAISE;
  			break;
  		case Opt_dont_appraise:
  			ima_log_string(ab, "action", "dont_appraise");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = DONT_APPRAISE;
  			break;
  		case Opt_audit:
  			ima_log_string(ab, "action", "audit");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = AUDIT;
  			break;
  		case Opt_func:
  			ima_log_string(ab, "func", args[0].from);
  
  			if (entry->func)
  				result = -EINVAL;
  
  			if (strcmp(args[0].from, "FILE_CHECK") == 0)
  				entry->func = FILE_CHECK;
  			/* PATH_CHECK is for backwards compat */
  			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
  				entry->func = FILE_CHECK;
  			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
  				entry->func = MODULE_CHECK;
  			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
  				entry->func = FIRMWARE_CHECK;
  			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
  				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
  				entry->func = MMAP_CHECK;
  			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
  				entry->func = BPRM_CHECK;
  			else
  				result = -EINVAL;
  			if (!result)
  				entry->flags |= IMA_FUNC;
  			break;
  		case Opt_mask:
  			ima_log_string(ab, "mask", args[0].from);
  
  			if (entry->mask)
  				result = -EINVAL;
  
  			if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
  				entry->mask = MAY_EXEC;
  			else if (strcmp(args[0].from, "MAY_WRITE") == 0)
  				entry->mask = MAY_WRITE;
  			else if (strcmp(args[0].from, "MAY_READ") == 0)
  				entry->mask = MAY_READ;
  			else if (strcmp(args[0].from, "MAY_APPEND") == 0)
  				entry->mask = MAY_APPEND;
  			else
  				result = -EINVAL;
  			if (!result)
  				entry->flags |= IMA_MASK;
  			break;
  		case Opt_fsmagic:
  			ima_log_string(ab, "fsmagic", args[0].from);
  
  			if (entry->fsmagic) {
  				result = -EINVAL;
  				break;
  			}
  
  			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
  			if (!result)
  				entry->flags |= IMA_FSMAGIC;
  			break;
  		case Opt_fsuuid:
  			ima_log_string(ab, "fsuuid", args[0].from);
  
  			if (memchr_inv(entry->fsuuid, 0x00,
  				       sizeof(entry->fsuuid))) {
  				result = -EINVAL;
  				break;
  			}
  
  			result = blk_part_pack_uuid(args[0].from,
  						    entry->fsuuid);
  			if (!result)
  				entry->flags |= IMA_FSUUID;
  			break;
  		case Opt_uid:
  			ima_log_string(ab, "uid", args[0].from);
  
  			if (uid_valid(entry->uid)) {
  				result = -EINVAL;
  				break;
  			}
  
  			result = kstrtoul(args[0].from, 10, &lnum);
  			if (!result) {
  				entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
  				if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
  					result = -EINVAL;
  				else
  					entry->flags |= IMA_UID;
  			}
  			break;
  		case Opt_fowner:
  			ima_log_string(ab, "fowner", args[0].from);
  
  			if (uid_valid(entry->fowner)) {
  				result = -EINVAL;
  				break;
  			}
  
  			result = kstrtoul(args[0].from, 10, &lnum);
  			if (!result) {
  				entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
  				if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
  					result = -EINVAL;
  				else
  					entry->flags |= IMA_FOWNER;
  			}
  			break;
  		case Opt_obj_user:
  			ima_log_string(ab, "obj_user", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_OBJ_USER,
  						   AUDIT_OBJ_USER);
  			break;
  		case Opt_obj_role:
  			ima_log_string(ab, "obj_role", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_OBJ_ROLE,
  						   AUDIT_OBJ_ROLE);
  			break;
  		case Opt_obj_type:
  			ima_log_string(ab, "obj_type", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_OBJ_TYPE,
  						   AUDIT_OBJ_TYPE);
  			break;
  		case Opt_subj_user:
  			ima_log_string(ab, "subj_user", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_SUBJ_USER,
  						   AUDIT_SUBJ_USER);
  			break;
  		case Opt_subj_role:
  			ima_log_string(ab, "subj_role", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_SUBJ_ROLE,
  						   AUDIT_SUBJ_ROLE);
  			break;
  		case Opt_subj_type:
  			ima_log_string(ab, "subj_type", args[0].from);
  			result = ima_lsm_rule_init(entry, args,
  						   LSM_SUBJ_TYPE,
  						   AUDIT_SUBJ_TYPE);
  			break;
  		case Opt_appraise_type:
  			if (entry->action != APPRAISE) {
  				result = -EINVAL;
  				break;
  			}
  
  			ima_log_string(ab, "appraise_type", args[0].from);
  			if ((strcmp(args[0].from, "imasig")) == 0)
  				entry->flags |= IMA_DIGSIG_REQUIRED;
  			else
  				result = -EINVAL;
  			break;
  		case Opt_permit_directio:
  			entry->flags |= IMA_PERMIT_DIRECTIO;
  			break;
  		case Opt_err:
  			ima_log_string(ab, "UNKNOWN", p);
  			result = -EINVAL;
  			break;
  		}
  	}
  	if (!result && (entry->action == UNKNOWN))
  		result = -EINVAL;
  	else if (entry->func == MODULE_CHECK)
  		ima_appraise |= IMA_APPRAISE_MODULES;
  	else if (entry->func == FIRMWARE_CHECK)
  		ima_appraise |= IMA_APPRAISE_FIRMWARE;
  	audit_log_format(ab, "res=%d", !result);
  	audit_log_end(ab);
  	return result;
  }
  
  /**
   * ima_parse_add_rule - add a rule to ima_policy_rules
   * @rule - ima measurement policy rule
   *
   * Uses a mutex to protect the policy list from multiple concurrent writers.
   * Returns the length of the rule parsed, an error code on failure
   */
  ssize_t ima_parse_add_rule(char *rule)
  {
  	static const char op[] = "update_policy";
  	char *p;
  	struct ima_rule_entry *entry;
  	ssize_t result, len;
  	int audit_info = 0;
  
  	p = strsep(&rule, "\n");
  	len = strlen(p) + 1;
  	p += strspn(p, " \t");
  
  	if (*p == '#' || *p == '\0')
  		return len;
  
  	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
  	if (!entry) {
  		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
  				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
  		return -ENOMEM;
  	}
  
  	INIT_LIST_HEAD(&entry->list);
  
  	result = ima_parse_rule(p, entry);
  	if (result) {
  		kfree(entry);
  		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
  				    NULL, op, "invalid-policy", result,
  				    audit_info);
  		return result;
  	}
  
  	mutex_lock(&ima_rules_mutex);
  	list_add_tail(&entry->list, &ima_policy_rules);
  	mutex_unlock(&ima_rules_mutex);
  
  	return len;
  }
  
  /* ima_delete_rules called to cleanup invalid policy */
  void ima_delete_rules(void)
  {
  	struct ima_rule_entry *entry, *tmp;
  	int i;
  
  	mutex_lock(&ima_rules_mutex);
  	list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
  		for (i = 0; i < MAX_LSM_RULES; i++)
  			kfree(entry->lsm[i].args_p);
  
  		list_del(&entry->list);
  		kfree(entry);
  	}
  	mutex_unlock(&ima_rules_mutex);
  }
  