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/fs.h>
  #include <linux/security.h>
  #include <linux/magic.h>
  #include <linux/parser.h>
  #include <linux/slab.h>
  #include <linux/rculist.h>
  #include <linux/genhd.h>
  #include <linux/seq_file.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 IMA_INMASK	0x0040
  #define IMA_EUID	0x0080
  #define IMA_PCR		0x0100
  #define IMA_FSNAME	0x0200
  
  #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
  #define HASH		0x0100
  #define DONT_HASH	0x0200
  
  #define INVALID_PCR(a) (((a) < 0) || \
  	(a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))
  
  int ima_policy_flag;
  static int temp_ima_appraise;
  
  #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
  };
  
  enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  
  struct ima_rule_entry {
  	struct list_head list;
  	int action;
  	unsigned int flags;
  	enum ima_hooks func;
  	int mask;
  	unsigned long fsmagic;
  	uuid_t fsuuid;
  	kuid_t uid;
  	kuid_t fowner;
  	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
  	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
  	int pcr;
  	struct {
  		void *rule;	/* LSM file metadata specific */
  		void *args_p;	/* audit value */
  		int type;	/* audit type */
  	} lsm[MAX_LSM_RULES];
  	char *fsname;
  };
  
  /*
   * 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 dont_measure_rules[] __ro_after_init = {
  	{.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 = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
  	 .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
  	 .flags = IMA_FSMAGIC},
  	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}
  };
  
  static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
  	{.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, .uid_op = &uid_eq,
  	 .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_measurement_rules[] __ro_after_init = {
  	{.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, .uid_op = &uid_eq,
  	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
  	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
  	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
  	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
  	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
  	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
  };
  
  static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
  	{.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 = SMACK_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  #ifdef CONFIG_IMA_WRITE_POLICY
  	{.action = APPRAISE, .func = POLICY_CHECK,
  	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
  #endif
  #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
  	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
  	 .flags = IMA_FOWNER},
  #else
  	/* force signature */
  	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
  	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
  #endif
  };
  
  static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
  	{.action = APPRAISE, .func = MODULE_CHECK,
  	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
  	{.action = APPRAISE, .func = FIRMWARE_CHECK,
  	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
  	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
  	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
  	{.action = APPRAISE, .func = POLICY_CHECK,
  	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
  };
  
  static LIST_HEAD(ima_default_rules);
  static LIST_HEAD(ima_policy_rules);
  static LIST_HEAD(ima_temp_rules);
  static struct list_head *ima_rules;
  
  static int ima_policy __initdata;
  
  static int __init default_measure_policy_setup(char *str)
  {
  	if (ima_policy)
  		return 1;
  
  	ima_policy = ORIGINAL_TCB;
  	return 1;
  }
  __setup("ima_tcb", default_measure_policy_setup);
  
  static bool ima_use_appraise_tcb __initdata;
  static bool ima_use_secure_boot __initdata;
  static bool ima_fail_unverifiable_sigs __ro_after_init;
  static int __init policy_setup(char *str)
  {
  	char *p;
  
  	while ((p = strsep(&str, " |\n")) != NULL) {
  		if (*p == ' ')
  			continue;
  		if ((strcmp(p, "tcb") == 0) && !ima_policy)
  			ima_policy = DEFAULT_TCB;
  		else if (strcmp(p, "appraise_tcb") == 0)
  			ima_use_appraise_tcb = true;
  		else if (strcmp(p, "secure_boot") == 0)
  			ima_use_secure_boot = true;
  		else if (strcmp(p, "fail_securely") == 0)
  			ima_fail_unverifiable_sigs = true;
  	}
  
  	return 1;
  }
  __setup("ima_policy=", policy_setup);
  
  static int __init default_appraise_policy_setup(char *str)
  {
  	ima_use_appraise_tcb = true;
  	return 1;
  }
  __setup("ima_appraise_tcb", default_appraise_policy_setup);
  
  /*
   * 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;
  	int result;
  	int i;
  
  	list_for_each_entry(entry, &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);
  		}
  	}
  }
  
  /**
   * ima_match_rules - determine whether an inode matches the measure rule.
   * @rule: a pointer to a rule
   * @inode: a pointer to an inode
   * @cred: a pointer to a credentials structure for user validation
   * @secid: the secid of the task to be validated
   * @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,
  			    const struct cred *cred, u32 secid,
  			    enum ima_hooks func, int mask)
  {
  	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_INMASK) &&
  	    (!(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_FSNAME)
  	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
  		return false;
  	if ((rule->flags & IMA_FSUUID) &&
  	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
  		return false;
  	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
  		return false;
  	if (rule->flags & IMA_EUID) {
  		if (has_capability_noaudit(current, CAP_SETUID)) {
  			if (!rule->uid_op(cred->euid, rule->uid)
  			    && !rule->uid_op(cred->suid, rule->uid)
  			    && !rule->uid_op(cred->uid, rule->uid))
  				return false;
  		} else if (!rule->uid_op(cred->euid, rule->uid))
  			return false;
  	}
  
  	if ((rule->flags & IMA_FOWNER) &&
  	    !rule->fowner_op(inode->i_uid, rule->fowner))
  		return false;
  	for (i = 0; i < MAX_LSM_RULES; i++) {
  		int rc = 0;
  		u32 osid;
  		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:
  			rc = security_filter_rule_match(secid,
  							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, enum ima_hooks 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 CREDS_CHECK:
  		return IMA_CREDS_APPRAISE;
  	case FILE_CHECK:
  	case POST_SETATTR:
  		return IMA_FILE_APPRAISE;
  	case MODULE_CHECK ... MAX_CHECK - 1:
  	default:
  		return IMA_READ_APPRAISE;
  	}
  }
  
  /**
   * ima_match_policy - decision based on LSM and other conditions
   * @inode: pointer to an inode for which the policy decision is being made
   * @cred: pointer to a credentials structure for which the policy decision is
   *        being made
   * @secid: LSM secid of the task to be validated
   * @func: IMA hook identifier
   * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
   * @pcr: set the pcr to extend
   *
   * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
   * conditions.
   *
   * Since the IMA policy may be updated multiple times we need to lock the
   * list when walking it.  Reads are many orders of magnitude more numerous
   * than writes so ima_match_policy() is classical RCU candidate.
   */
  int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
  		     enum ima_hooks func, int mask, int flags, int *pcr)
  {
  	struct ima_rule_entry *entry;
  	int action = 0, actmask = flags | (flags << 1);
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(entry, ima_rules, list) {
  
  		if (!(entry->action & actmask))
  			continue;
  
  		if (!ima_match_rules(entry, inode, cred, secid, 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);
  			action &= ~IMA_HASH;
  			if (ima_fail_unverifiable_sigs)
  				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
  		}
  
  		if (entry->action & IMA_DO_MASK)
  			actmask &= ~(entry->action | entry->action << 1);
  		else
  			actmask &= ~(entry->action | entry->action >> 1);
  
  		if ((pcr) && (entry->flags & IMA_PCR))
  			*pcr = entry->pcr;
  
  		if (!actmask)
  			break;
  	}
  	rcu_read_unlock();
  
  	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;
  
  	list_for_each_entry(entry, ima_rules, list) {
  		if (entry->action & IMA_DO_MASK)
  			ima_policy_flag |= entry->action;
  	}
  
  	ima_appraise |= temp_ima_appraise;
  	if (!ima_appraise)
  		ima_policy_flag &= ~IMA_APPRAISE;
  }
  
  static int ima_appraise_flag(enum ima_hooks func)
  {
  	if (func == MODULE_CHECK)
  		return IMA_APPRAISE_MODULES;
  	else if (func == FIRMWARE_CHECK)
  		return IMA_APPRAISE_FIRMWARE;
  	else if (func == POLICY_CHECK)
  		return IMA_APPRAISE_POLICY;
  	return 0;
  }
  
  /**
   * 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, secure_boot_entries;
  
  	/* if !ima_policy set entries = 0 so we load NO default rules */
  	measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0;
  	appraise_entries = ima_use_appraise_tcb ?
  			 ARRAY_SIZE(default_appraise_rules) : 0;
  	secure_boot_entries = ima_use_secure_boot ?
  			ARRAY_SIZE(secure_boot_rules) : 0;
  
  	for (i = 0; i < measure_entries; i++)
  		list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);
  
  	switch (ima_policy) {
  	case ORIGINAL_TCB:
  		for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++)
  			list_add_tail(&original_measurement_rules[i].list,
  				      &ima_default_rules);
  		break;
  	case DEFAULT_TCB:
  		for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++)
  			list_add_tail(&default_measurement_rules[i].list,
  				      &ima_default_rules);
  	default:
  		break;
  	}
  
  	/*
  	 * Insert the appraise rules requiring file signatures, prior to
  	 * any other appraise rules.
  	 */
  	for (i = 0; i < secure_boot_entries; i++) {
  		list_add_tail(&secure_boot_rules[i].list, &ima_default_rules);
  		temp_ima_appraise |=
  		    ima_appraise_flag(secure_boot_rules[i].func);
  	}
  
  	for (i = 0; i < appraise_entries; i++) {
  		list_add_tail(&default_appraise_rules[i].list,
  			      &ima_default_rules);
  		if (default_appraise_rules[i].func == POLICY_CHECK)
  			temp_ima_appraise |= IMA_APPRAISE_POLICY;
  	}
  
  	ima_rules = &ima_default_rules;
  	ima_update_policy_flag();
  }
  
  /* Make sure we have a valid policy, at least containing some rules. */
  int ima_check_policy(void)
  {
  	if (list_empty(&ima_temp_rules))
  		return -EINVAL;
  	return 0;
  }
  
  /**
   * ima_update_policy - update default_rules with new measure rules
   *
   * Called on file .release to update the default rules with a complete new
   * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
   * they make a queue.  The policy may be updated multiple times and this is the
   * RCU updater.
   *
   * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
   * we switch from the default policy to user defined.
   */
  void ima_update_policy(void)
  {
  	struct list_head *policy = &ima_policy_rules;
  
  	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
  
  	if (ima_rules != policy) {
  		ima_policy_flag = 0;
  		ima_rules = policy;
  	}
  	ima_update_policy_flag();
  }
  
  enum {
  	Opt_err = -1,
  	Opt_measure = 1, Opt_dont_measure,
  	Opt_appraise, Opt_dont_appraise,
  	Opt_audit, Opt_hash, Opt_dont_hash,
  	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_fsname,
  	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
  	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
  	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
  	Opt_appraise_type, Opt_permit_directio,
  	Opt_pcr
  };
  
  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_hash, "hash"},
  	{Opt_dont_hash, "dont_hash"},
  	{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_fsname, "fsname=%s"},
  	{Opt_fsuuid, "fsuuid=%s"},
  	{Opt_uid_eq, "uid=%s"},
  	{Opt_euid_eq, "euid=%s"},
  	{Opt_fowner_eq, "fowner=%s"},
  	{Opt_uid_gt, "uid>%s"},
  	{Opt_euid_gt, "euid>%s"},
  	{Opt_fowner_gt, "fowner>%s"},
  	{Opt_uid_lt, "uid<%s"},
  	{Opt_euid_lt, "euid<%s"},
  	{Opt_fowner_lt, "fowner<%s"},
  	{Opt_appraise_type, "appraise_type=%s"},
  	{Opt_permit_directio, "permit_directio"},
  	{Opt_pcr, "pcr=%s"},
  	{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_op(struct audit_buffer *ab, char *key, char *value,
  			      bool (*rule_operator)(kuid_t, kuid_t))
  {
  	if (rule_operator == &uid_gt)
  		audit_log_format(ab, "%s>", key);
  	else if (rule_operator == &uid_lt)
  		audit_log_format(ab, "%s<", key);
  	else
  		audit_log_format(ab, "%s=", key);
  	audit_log_untrustedstring(ab, value);
  	audit_log_format(ab, " ");
  }
  static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
  {
  	ima_log_string_op(ab, key, value, NULL);
  }
  
  static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
  {
  	struct audit_buffer *ab;
  	char *from;
  	char *p;
  	bool uid_token;
  	int result = 0;
  
  	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
  
  	entry->uid = INVALID_UID;
  	entry->fowner = INVALID_UID;
  	entry->uid_op = &uid_eq;
  	entry->fowner_op = &uid_eq;
  	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_hash:
  			ima_log_string(ab, "action", "hash");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = HASH;
  			break;
  		case Opt_dont_hash:
  			ima_log_string(ab, "action", "dont_hash");
  
  			if (entry->action != UNKNOWN)
  				result = -EINVAL;
  
  			entry->action = DONT_HASH;
  			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 if (strcmp(args[0].from, "CREDS_CHECK") == 0)
  				entry->func = CREDS_CHECK;
  			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
  				 0)
  				entry->func = KEXEC_KERNEL_CHECK;
  			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
  				 == 0)
  				entry->func = KEXEC_INITRAMFS_CHECK;
  			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
  				entry->func = POLICY_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;
  
  			from = args[0].from;
  			if (*from == '^')
  				from++;
  
  			if ((strcmp(from, "MAY_EXEC")) == 0)
  				entry->mask = MAY_EXEC;
  			else if (strcmp(from, "MAY_WRITE") == 0)
  				entry->mask = MAY_WRITE;
  			else if (strcmp(from, "MAY_READ") == 0)
  				entry->mask = MAY_READ;
  			else if (strcmp(from, "MAY_APPEND") == 0)
  				entry->mask = MAY_APPEND;
  			else
  				result = -EINVAL;
  			if (!result)
  				entry->flags |= (*args[0].from == '^')
  				     ? IMA_INMASK : 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_fsname:
  			ima_log_string(ab, "fsname", args[0].from);
  
  			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
  			if (!entry->fsname) {
  				result = -ENOMEM;
  				break;
  			}
  			result = 0;
  			entry->flags |= IMA_FSNAME;
  			break;
  		case Opt_fsuuid:
  			ima_log_string(ab, "fsuuid", args[0].from);
  
  			if (!uuid_is_null(&entry->fsuuid)) {
  				result = -EINVAL;
  				break;
  			}
  
  			result = uuid_parse(args[0].from, &entry->fsuuid);
  			if (!result)
  				entry->flags |= IMA_FSUUID;
  			break;
  		case Opt_uid_gt:
  		case Opt_euid_gt:
  			entry->uid_op = &uid_gt;
  		case Opt_uid_lt:
  		case Opt_euid_lt:
  			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
  				entry->uid_op = &uid_lt;
  		case Opt_uid_eq:
  		case Opt_euid_eq:
  			uid_token = (token == Opt_uid_eq) ||
  				    (token == Opt_uid_gt) ||
  				    (token == Opt_uid_lt);
  
  			ima_log_string_op(ab, uid_token ? "uid" : "euid",
  					  args[0].from, entry->uid_op);
  
  			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 |= uid_token
  					    ? IMA_UID : IMA_EUID;
  			}
  			break;
  		case Opt_fowner_gt:
  			entry->fowner_op = &uid_gt;
  		case Opt_fowner_lt:
  			if (token == Opt_fowner_lt)
  				entry->fowner_op = &uid_lt;
  		case Opt_fowner_eq:
  			ima_log_string_op(ab, "fowner", args[0].from,
  					  entry->fowner_op);
  
  			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_pcr:
  			if (entry->action != MEASURE) {
  				result = -EINVAL;
  				break;
  			}
  			ima_log_string(ab, "pcr", args[0].from);
  
  			result = kstrtoint(args[0].from, 10, &entry->pcr);
  			if (result || INVALID_PCR(entry->pcr))
  				result = -EINVAL;
  			else
  				entry->flags |= IMA_PCR;
  
  			break;
  		case Opt_err:
  			ima_log_string(ab, "UNKNOWN", p);
  			result = -EINVAL;
  			break;
  		}
  	}
  	if (!result && (entry->action == UNKNOWN))
  		result = -EINVAL;
  	else if (entry->action == APPRAISE)
  		temp_ima_appraise |= ima_appraise_flag(entry->func);
  
  	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
   *
   * Avoid locking by allowing just one writer at a time in ima_write_policy()
   * 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;
  	}
  
  	list_add_tail(&entry->list, &ima_temp_rules);
  
  	return len;
  }
  
  /**
   * ima_delete_rules() called to cleanup invalid in-flight policy.
   * We don't need locking as we operate on the temp list, which is
   * different from the active one.  There is also only one user of
   * ima_delete_rules() at a time.
   */
  void ima_delete_rules(void)
  {
  	struct ima_rule_entry *entry, *tmp;
  	int i;
  
  	temp_ima_appraise = 0;
  	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
  		for (i = 0; i < MAX_LSM_RULES; i++)
  			kfree(entry->lsm[i].args_p);
  
  		list_del(&entry->list);
  		kfree(entry);
  	}
  }
  
  #ifdef	CONFIG_IMA_READ_POLICY
  enum {
  	mask_exec = 0, mask_write, mask_read, mask_append
  };
  
  static const char *const mask_tokens[] = {
  	"MAY_EXEC",
  	"MAY_WRITE",
  	"MAY_READ",
  	"MAY_APPEND"
  };
  
  #define __ima_hook_stringify(str)	(#str),
  
  static const char *const func_tokens[] = {
  	__ima_hooks(__ima_hook_stringify)
  };
  
  void *ima_policy_start(struct seq_file *m, loff_t *pos)
  {
  	loff_t l = *pos;
  	struct ima_rule_entry *entry;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(entry, ima_rules, list) {
  		if (!l--) {
  			rcu_read_unlock();
  			return entry;
  		}
  	}
  	rcu_read_unlock();
  	return NULL;
  }
  
  void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	struct ima_rule_entry *entry = v;
  
  	rcu_read_lock();
  	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
  	rcu_read_unlock();
  	(*pos)++;
  
  	return (&entry->list == ima_rules) ? NULL : entry;
  }
  
  void ima_policy_stop(struct seq_file *m, void *v)
  {
  }
  
  #define pt(token)	policy_tokens[token + Opt_err].pattern
  #define mt(token)	mask_tokens[token]
  
  /*
   * policy_func_show - display the ima_hooks policy rule
   */
  static void policy_func_show(struct seq_file *m, enum ima_hooks func)
  {
  	if (func > 0 && func < MAX_CHECK)
  		seq_printf(m, "func=%s ", func_tokens[func]);
  	else
  		seq_printf(m, "func=%d ", func);
  }
  
  int ima_policy_show(struct seq_file *m, void *v)
  {
  	struct ima_rule_entry *entry = v;
  	int i;
  	char tbuf[64] = {0,};
  
  	rcu_read_lock();
  
  	if (entry->action & MEASURE)
  		seq_puts(m, pt(Opt_measure));
  	if (entry->action & DONT_MEASURE)
  		seq_puts(m, pt(Opt_dont_measure));
  	if (entry->action & APPRAISE)
  		seq_puts(m, pt(Opt_appraise));
  	if (entry->action & DONT_APPRAISE)
  		seq_puts(m, pt(Opt_dont_appraise));
  	if (entry->action & AUDIT)
  		seq_puts(m, pt(Opt_audit));
  	if (entry->action & HASH)
  		seq_puts(m, pt(Opt_hash));
  	if (entry->action & DONT_HASH)
  		seq_puts(m, pt(Opt_dont_hash));
  
  	seq_puts(m, " ");
  
  	if (entry->flags & IMA_FUNC)
  		policy_func_show(m, entry->func);
  
  	if (entry->flags & IMA_MASK) {
  		if (entry->mask & MAY_EXEC)
  			seq_printf(m, pt(Opt_mask), mt(mask_exec));
  		if (entry->mask & MAY_WRITE)
  			seq_printf(m, pt(Opt_mask), mt(mask_write));
  		if (entry->mask & MAY_READ)
  			seq_printf(m, pt(Opt_mask), mt(mask_read));
  		if (entry->mask & MAY_APPEND)
  			seq_printf(m, pt(Opt_mask), mt(mask_append));
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_FSMAGIC) {
  		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
  		seq_printf(m, pt(Opt_fsmagic), tbuf);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_FSNAME) {
  		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
  		seq_printf(m, pt(Opt_fsname), tbuf);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_PCR) {
  		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
  		seq_printf(m, pt(Opt_pcr), tbuf);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_FSUUID) {
  		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_UID) {
  		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
  		if (entry->uid_op == &uid_gt)
  			seq_printf(m, pt(Opt_uid_gt), tbuf);
  		else if (entry->uid_op == &uid_lt)
  			seq_printf(m, pt(Opt_uid_lt), tbuf);
  		else
  			seq_printf(m, pt(Opt_uid_eq), tbuf);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_EUID) {
  		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
  		if (entry->uid_op == &uid_gt)
  			seq_printf(m, pt(Opt_euid_gt), tbuf);
  		else if (entry->uid_op == &uid_lt)
  			seq_printf(m, pt(Opt_euid_lt), tbuf);
  		else
  			seq_printf(m, pt(Opt_euid_eq), tbuf);
  		seq_puts(m, " ");
  	}
  
  	if (entry->flags & IMA_FOWNER) {
  		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
  		if (entry->fowner_op == &uid_gt)
  			seq_printf(m, pt(Opt_fowner_gt), tbuf);
  		else if (entry->fowner_op == &uid_lt)
  			seq_printf(m, pt(Opt_fowner_lt), tbuf);
  		else
  			seq_printf(m, pt(Opt_fowner_eq), tbuf);
  		seq_puts(m, " ");
  	}
  
  	for (i = 0; i < MAX_LSM_RULES; i++) {
  		if (entry->lsm[i].rule) {
  			switch (i) {
  			case LSM_OBJ_USER:
  				seq_printf(m, pt(Opt_obj_user),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			case LSM_OBJ_ROLE:
  				seq_printf(m, pt(Opt_obj_role),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			case LSM_OBJ_TYPE:
  				seq_printf(m, pt(Opt_obj_type),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			case LSM_SUBJ_USER:
  				seq_printf(m, pt(Opt_subj_user),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			case LSM_SUBJ_ROLE:
  				seq_printf(m, pt(Opt_subj_role),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			case LSM_SUBJ_TYPE:
  				seq_printf(m, pt(Opt_subj_type),
  					   (char *)entry->lsm[i].args_p);
  				break;
  			}
  		}
  	}
  	if (entry->flags & IMA_DIGSIG_REQUIRED)
  		seq_puts(m, "appraise_type=imasig ");
  	if (entry->flags & IMA_PERMIT_DIRECTIO)
  		seq_puts(m, "permit_directio ");
  	rcu_read_unlock();
  	seq_puts(m, "\n");
  	return 0;
  }
  #endif	/* CONFIG_IMA_READ_POLICY */
  