[deliverable/linux.git] / security / integrity / ima / ima_policy.c

/*
 * 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 "ima.h"

/* flags definitions */
#define IMA_FUNC 	0x0001
#define IMA_MASK 	0x0002
#define IMA_FSMAGIC	0x0004
#define IMA_UID		0x0008

enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };

#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_measure_rule_entry {
	struct list_head list;
	enum ima_action action;
	unsigned int flags;
	enum ima_hooks func;
	int mask;
	unsigned long fsmagic;
	uid_t uid;
	struct {
		void *rule;	/* LSM file metadata specific */
		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, and .uid
 */

/*
 * 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_measure_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 = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
	{.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
	{.action = MEASURE,.func = FILE_MMAP,.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 = 0,
	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
};

static LIST_HEAD(measure_default_rules);
static LIST_HEAD(measure_policy_rules);
static struct list_head *ima_measure;

static DEFINE_MUTEX(ima_measure_mutex);

static bool ima_use_tcb __initdata;
static int __init default_policy_setup(char *str)
{
	ima_use_tcb = 1;
	return 1;
}
__setup("ima_tcb", default_policy_setup);

/**
 * 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_measure_rule_entry *rule,
			    struct inode *inode, enum ima_hooks func, int mask)
{
	struct task_struct *tsk = current;
	int i;

	if ((rule->flags & IMA_FUNC) && rule->func != func)
		return false;
	if ((rule->flags & IMA_MASK) && rule->mask != mask)
		return false;
	if ((rule->flags & IMA_FSMAGIC)
	    && rule->fsmagic != inode->i_sb->s_magic)
		return false;
	if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
		return false;
	for (i = 0; i < MAX_LSM_RULES; i++) {
		int rc = 0;
		u32 osid, sid;

		if (!rule->lsm[i].rule)
			continue;

		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)
			return false;
	}
	return true;
}

/**
 * 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)
{
	struct ima_measure_rule_entry *entry;

	list_for_each_entry(entry, ima_measure, list) {
		bool rc;

		rc = ima_match_rules(entry, inode, func, mask);
		if (rc)
			return entry->action;
	}
	return 0;
}

/**
 * ima_init_policy - initialize the default measure rules.
 *
 * ima_measure points to either the measure_default_rules or the
 * the new measure_policy_rules.
 */
void __init ima_init_policy(void)
{
	int i, entries;

	/* if !ima_use_tcb set entries = 0 so we load NO default rules */
	if (ima_use_tcb)
		entries = ARRAY_SIZE(default_rules);
	else
		entries = 0;

	for (i = 0; i < entries; i++)
		list_add_tail(&default_rules[i].list, &measure_default_rules);
	ima_measure = &measure_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)
{
	const char *op = "policy_update";
	const char *cause = "already exists";
	int result = 1;
	int audit_info = 0;

	if (ima_measure == &measure_default_rules) {
		ima_measure = &measure_policy_rules;
		cause = "complete";
		result = 0;
	}
	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
			    NULL, op, cause, result, audit_info);
}

enum {
	Opt_err = -1,
	Opt_measure = 1, Opt_dont_measure,
	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
};

static match_table_t policy_tokens = {
	{Opt_measure, "measure"},
	{Opt_dont_measure, "dont_measure"},
	{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_uid, "uid=%s"},
	{Opt_err, NULL}
};

static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
			     char *args, int lsm_rule, int audit_type)
{
	int result;

	if (entry->lsm[lsm_rule].rule)
		return -EINVAL;

	entry->lsm[lsm_rule].type = audit_type;
	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
					   Audit_equal, args,
					   &entry->lsm[lsm_rule].rule);
	return result;
}

static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
{
	struct audit_buffer *ab;
	char *p;
	int result = 0;

	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);

	entry->uid = -1;
	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:
			audit_log_format(ab, "%s ", "measure");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = MEASURE;
			break;
		case Opt_dont_measure:
			audit_log_format(ab, "%s ", "dont_measure");

			if (entry->action != UNKNOWN)
				result = -EINVAL;

			entry->action = DONT_MEASURE;
			break;
		case Opt_func:
			audit_log_format(ab, "func=%s ", 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, "FILE_MMAP") == 0)
				entry->func = FILE_MMAP;
			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:
			audit_log_format(ab, "mask=%s ", 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:
			audit_log_format(ab, "fsmagic=%s ", args[0].from);

			if (entry->fsmagic) {
				result = -EINVAL;
				break;
			}

			result = strict_strtoul(args[0].from, 16,
						&entry->fsmagic);
			if (!result)
				entry->flags |= IMA_FSMAGIC;
			break;
		case Opt_uid:
			audit_log_format(ab, "uid=%s ", args[0].from);

			if (entry->uid != -1) {
				result = -EINVAL;
				break;
			}

			result = strict_strtoul(args[0].from, 10, &lnum);
			if (!result) {
				entry->uid = (uid_t) lnum;
				if (entry->uid != lnum)
					result = -EINVAL;
				else
					entry->flags |= IMA_UID;
			}
			break;
		case Opt_obj_user:
			audit_log_format(ab, "obj_user=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_OBJ_USER,
						   AUDIT_OBJ_USER);
			break;
		case Opt_obj_role:
			audit_log_format(ab, "obj_role=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_OBJ_ROLE,
						   AUDIT_OBJ_ROLE);
			break;
		case Opt_obj_type:
			audit_log_format(ab, "obj_type=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_OBJ_TYPE,
						   AUDIT_OBJ_TYPE);
			break;
		case Opt_subj_user:
			audit_log_format(ab, "subj_user=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_SUBJ_USER,
						   AUDIT_SUBJ_USER);
			break;
		case Opt_subj_role:
			audit_log_format(ab, "subj_role=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_SUBJ_ROLE,
						   AUDIT_SUBJ_ROLE);
			break;
		case Opt_subj_type:
			audit_log_format(ab, "subj_type=%s ", args[0].from);
			result = ima_lsm_rule_init(entry, args[0].from,
						   LSM_SUBJ_TYPE,
						   AUDIT_SUBJ_TYPE);
			break;
		case Opt_err:
			result = -EINVAL;
			audit_log_format(ab, "UNKNOWN=%s ", p);
			break;
		}
	}
	if (!result && (entry->action == UNKNOWN))
		result = -EINVAL;

	audit_log_format(ab, "res=%d", !!result);
	audit_log_end(ab);
	return result;
}

/**
 * ima_parse_add_rule - add a rule to measure_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)
{
	const char *op = "update_policy";
	char *p;
	struct ima_measure_rule_entry *entry;
	ssize_t result, len;
	int audit_info = 0;

	/* Prevent installed policy from changing */
	if (ima_measure != &measure_default_rules) {
		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
				    NULL, op, "already exists",
				    -EACCES, audit_info);
		return -EACCES;
	}

	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);

	p = strsep(&rule, "\n");
	len = strlen(p) + 1;

	if (*p == '#') {
		kfree(entry);
		return len;
	}

	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_measure_mutex);
	list_add_tail(&entry->list, &measure_policy_rules);
	mutex_unlock(&ima_measure_mutex);

	return len;
}

/* ima_delete_rules called to cleanup invalid policy */
void ima_delete_rules(void)
{
	struct ima_measure_rule_entry *entry, *tmp;

	mutex_lock(&ima_measure_mutex);
	list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) {
		list_del(&entry->list);
		kfree(entry);
	}
	mutex_unlock(&ima_measure_mutex);
}
Commit	Line	Data
3323eec9 MZ	1	/*
	2	* Copyright (C) 2008 IBM Corporation
	3	* Author: Mimi Zohar <zohar@us.ibm.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation, version 2 of the License.
	8	*
	9	* ima_policy.c
	10	* - initialize default measure policy rules
	11	*
	12	*/
	13	#include <linux/module.h>
	14	#include <linux/list.h>
3323eec9 MZ	15	#include <linux/security.h>
3323eec9 MZ	16	#include <linux/magic.h>
4af4662f	17	#include <linux/parser.h>
3323eec9 MZ	18
	19	#include "ima.h"
	20
	21	/* flags definitions */
	22	#define IMA_FUNC 0x0001
	23	#define IMA_MASK 0x0002
	24	#define IMA_FSMAGIC 0x0004
	25	#define IMA_UID 0x0008
	26
4af4662f MZ	27	enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };
	28
	29	#define MAX_LSM_RULES 6
	30	enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
	31	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
	32	};
3323eec9 MZ	33
	34	struct ima_measure_rule_entry {
	35	struct list_head list;
	36	enum ima_action action;
	37	unsigned int flags;
	38	enum ima_hooks func;
	39	int mask;
	40	unsigned long fsmagic;
	41	uid_t uid;
4af4662f MZ	42	struct {
	43	void rule; / LSM file metadata specific */
	44	int type; /* audit type */
	45	} lsm[MAX_LSM_RULES];
3323eec9 MZ	46	};
3323eec9 MZ	47
5789ba3b EP	48	/*
5789ba3b EP	49	* Without LSM specific knowledge, the default policy can only be
4af4662f MZ	50	* written in terms of .action, .func, .mask, .fsmagic, and .uid
4af4662f MZ	51	*/
5789ba3b EP	52
	53	/*
	54	* The minimum rule set to allow for full TCB coverage. Measures all files
	55	* opened or mmap for exec and everything read by root. Dangerous because
	56	* normal users can easily run the machine out of memory simply building
	57	* and running executables.
	58	*/
3323eec9	59	static struct ima_measure_rule_entry default_rules[] = {
75834fc3	60	{.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
3323eec9 MZ	61	{.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
	62	{.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
	63	{.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
75834fc3 EP	64	{.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
75834fc3 EP	65	{.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
3323eec9 MZ	66	{.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC,
	67	.flags = IMA_FUNC \| IMA_MASK},
	68	{.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
	69	.flags = IMA_FUNC \| IMA_MASK},
1e93d005	70	{.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = 0,
5789ba3b	71	.flags = IMA_FUNC \| IMA_MASK \| IMA_UID},
3323eec9 MZ	72	};
	73
	74	static LIST_HEAD(measure_default_rules);
4af4662f	75	static LIST_HEAD(measure_policy_rules);
3323eec9 MZ	76	static struct list_head *ima_measure;
3323eec9 MZ	77
4af4662f MZ	78	static DEFINE_MUTEX(ima_measure_mutex);
4af4662f MZ	79
5789ba3b EP	80	static bool ima_use_tcb __initdata;
	81	static int __init default_policy_setup(char *str)
	82	{
	83	ima_use_tcb = 1;
	84	return 1;
	85	}
	86	__setup("ima_tcb", default_policy_setup);
	87
3323eec9 MZ	88	/**
	89	* ima_match_rules - determine whether an inode matches the measure rule.
	90	* @rule: a pointer to a rule
	91	* @inode: a pointer to an inode
	92	* @func: LIM hook identifier
	93	* @mask: requested action (MAY_READ \| MAY_WRITE \| MAY_APPEND \| MAY_EXEC)
	94	*
	95	* Returns true on rule match, false on failure.
	96	*/
	97	static bool ima_match_rules(struct ima_measure_rule_entry *rule,
	98	struct inode *inode, enum ima_hooks func, int mask)
	99	{
	100	struct task_struct *tsk = current;
4af4662f	101	int i;
3323eec9 MZ	102
	103	if ((rule->flags & IMA_FUNC) && rule->func != func)
	104	return false;
	105	if ((rule->flags & IMA_MASK) && rule->mask != mask)
	106	return false;
	107	if ((rule->flags & IMA_FSMAGIC)
	108	&& rule->fsmagic != inode->i_sb->s_magic)
	109	return false;
	110	if ((rule->flags & IMA_UID) && rule->uid != tsk->cred->uid)
	111	return false;
4af4662f	112	for (i = 0; i < MAX_LSM_RULES; i++) {
53fc0e22	113	int rc = 0;
4af4662f MZ	114	u32 osid, sid;
	115
	116	if (!rule->lsm[i].rule)
	117	continue;
	118
	119	switch (i) {
	120	case LSM_OBJ_USER:
	121	case LSM_OBJ_ROLE:
	122	case LSM_OBJ_TYPE:
	123	security_inode_getsecid(inode, &osid);
	124	rc = security_filter_rule_match(osid,
	125	rule->lsm[i].type,
53fc0e22	126	Audit_equal,
4af4662f MZ	127	rule->lsm[i].rule,
	128	NULL);
	129	break;
	130	case LSM_SUBJ_USER:
	131	case LSM_SUBJ_ROLE:
	132	case LSM_SUBJ_TYPE:
	133	security_task_getsecid(tsk, &sid);
	134	rc = security_filter_rule_match(sid,
	135	rule->lsm[i].type,
53fc0e22	136	Audit_equal,
4af4662f MZ	137	rule->lsm[i].rule,
	138	NULL);
	139	default:
	140	break;
	141	}
	142	if (!rc)
	143	return false;
	144	}
3323eec9 MZ	145	return true;
	146	}
	147
	148	/**
	149	* ima_match_policy - decision based on LSM and other conditions
	150	* @inode: pointer to an inode for which the policy decision is being made
	151	* @func: IMA hook identifier
	152	* @mask: requested action (MAY_READ \| MAY_WRITE \| MAY_APPEND \| MAY_EXEC)
	153	*
	154	* Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
	155	* conditions.
	156	*
	157	* (There is no need for locking when walking the policy list,
	158	* as elements in the list are never deleted, nor does the list
	159	* change.)
	160	*/
	161	int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
	162	{
	163	struct ima_measure_rule_entry *entry;
	164
	165	list_for_each_entry(entry, ima_measure, list) {
	166	bool rc;
	167
	168	rc = ima_match_rules(entry, inode, func, mask);
	169	if (rc)
	170	return entry->action;
	171	}
	172	return 0;
	173	}
	174
	175	/**
	176	* ima_init_policy - initialize the default measure rules.
	177	*
3323eec9	178	* ima_measure points to either the measure_default_rules or the
4af4662f	179	* the new measure_policy_rules.
3323eec9	180	*/
932995f0	181	void __init ima_init_policy(void)
3323eec9	182	{
5789ba3b EP	183	int i, entries;
	184
	185	/* if !ima_use_tcb set entries = 0 so we load NO default rules */
	186	if (ima_use_tcb)
	187	entries = ARRAY_SIZE(default_rules);
	188	else
	189	entries = 0;
3323eec9	190
5789ba3b	191	for (i = 0; i < entries; i++)
3323eec9 MZ	192	list_add_tail(&default_rules[i].list, &measure_default_rules);
	193	ima_measure = &measure_default_rules;
	194	}
4af4662f MZ	195
	196	/**
	197	* ima_update_policy - update default_rules with new measure rules
	198	*
	199	* Called on file .release to update the default rules with a complete new
	200	* policy. Once updated, the policy is locked, no additional rules can be
	201	* added to the policy.
	202	*/
	203	void ima_update_policy(void)
	204	{
	205	const char *op = "policy_update";
	206	const char *cause = "already exists";
	207	int result = 1;
	208	int audit_info = 0;
	209
	210	if (ima_measure == &measure_default_rules) {
	211	ima_measure = &measure_policy_rules;
	212	cause = "complete";
	213	result = 0;
	214	}
	215	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
	216	NULL, op, cause, result, audit_info);
	217	}
	218
	219	enum {
	220	Opt_err = -1,
	221	Opt_measure = 1, Opt_dont_measure,
	222	Opt_obj_user, Opt_obj_role, Opt_obj_type,
	223	Opt_subj_user, Opt_subj_role, Opt_subj_type,
	224	Opt_func, Opt_mask, Opt_fsmagic, Opt_uid
	225	};
	226
	227	static match_table_t policy_tokens = {
	228	{Opt_measure, "measure"},
	229	{Opt_dont_measure, "dont_measure"},
	230	{Opt_obj_user, "obj_user=%s"},
	231	{Opt_obj_role, "obj_role=%s"},
	232	{Opt_obj_type, "obj_type=%s"},
	233	{Opt_subj_user, "subj_user=%s"},
	234	{Opt_subj_role, "subj_role=%s"},
	235	{Opt_subj_type, "subj_type=%s"},
	236	{Opt_func, "func=%s"},
	237	{Opt_mask, "mask=%s"},
	238	{Opt_fsmagic, "fsmagic=%s"},
	239	{Opt_uid, "uid=%s"},
	240	{Opt_err, NULL}
	241	};
	242
	243	static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry,
	244	char *args, int lsm_rule, int audit_type)
	245	{
	246	int result;
	247
7b62e162 EP	248	if (entry->lsm[lsm_rule].rule)
	249	return -EINVAL;
	250
4af4662f MZ	251	entry->lsm[lsm_rule].type = audit_type;
4af4662f MZ	252	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
53fc0e22	253	Audit_equal, args,
4af4662f MZ	254	&entry->lsm[lsm_rule].rule);
	255	return result;
	256	}
	257
	258	static int ima_parse_rule(char rule, struct ima_measure_rule_entry entry)
	259	{
	260	struct audit_buffer *ab;
	261	char *p;
	262	int result = 0;
	263
523979ad	264	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
4af4662f	265
7b62e162	266	entry->uid = -1;
b9035b1f	267	entry->action = UNKNOWN;
28ef4002	268	while ((p = strsep(&rule, " \t")) != NULL) {
4af4662f MZ	269	substring_t args[MAX_OPT_ARGS];
	270	int token;
	271	unsigned long lnum;
	272
	273	if (result < 0)
	274	break;
28ef4002 EP	275	if ((p == '\0') \|\| (p == ' ') \|\| (*p == '\t'))
28ef4002 EP	276	continue;
4af4662f MZ	277	token = match_token(p, policy_tokens, args);
	278	switch (token) {
	279	case Opt_measure:
	280	audit_log_format(ab, "%s ", "measure");
7b62e162 EP	281
	282	if (entry->action != UNKNOWN)
	283	result = -EINVAL;
	284
4af4662f MZ	285	entry->action = MEASURE;
	286	break;
	287	case Opt_dont_measure:
	288	audit_log_format(ab, "%s ", "dont_measure");
7b62e162 EP	289
	290	if (entry->action != UNKNOWN)
	291	result = -EINVAL;
	292
4af4662f MZ	293	entry->action = DONT_MEASURE;
	294	break;
	295	case Opt_func:
	296	audit_log_format(ab, "func=%s ", args[0].from);
7b62e162 EP	297
	298	if (entry->func)
	299	result = -EINVAL;
	300
1e93d005 MZ	301	if (strcmp(args[0].from, "FILE_CHECK") == 0)
	302	entry->func = FILE_CHECK;
	303	/* PATH_CHECK is for backwards compat */
	304	else if (strcmp(args[0].from, "PATH_CHECK") == 0)
	305	entry->func = FILE_CHECK;
4af4662f MZ	306	else if (strcmp(args[0].from, "FILE_MMAP") == 0)
	307	entry->func = FILE_MMAP;
	308	else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
	309	entry->func = BPRM_CHECK;
	310	else
	311	result = -EINVAL;
	312	if (!result)
	313	entry->flags \|= IMA_FUNC;
	314	break;
	315	case Opt_mask:
	316	audit_log_format(ab, "mask=%s ", args[0].from);
7b62e162 EP	317
	318	if (entry->mask)
	319	result = -EINVAL;
	320
4af4662f MZ	321	if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
	322	entry->mask = MAY_EXEC;
	323	else if (strcmp(args[0].from, "MAY_WRITE") == 0)
	324	entry->mask = MAY_WRITE;
	325	else if (strcmp(args[0].from, "MAY_READ") == 0)
	326	entry->mask = MAY_READ;
	327	else if (strcmp(args[0].from, "MAY_APPEND") == 0)
	328	entry->mask = MAY_APPEND;
	329	else
	330	result = -EINVAL;
	331	if (!result)
	332	entry->flags \|= IMA_MASK;
	333	break;
	334	case Opt_fsmagic:
	335	audit_log_format(ab, "fsmagic=%s ", args[0].from);
7b62e162 EP	336
	337	if (entry->fsmagic) {
	338	result = -EINVAL;
	339	break;
	340	}
	341
4af4662f MZ	342	result = strict_strtoul(args[0].from, 16,
	343	&entry->fsmagic);
	344	if (!result)
	345	entry->flags \|= IMA_FSMAGIC;
	346	break;
	347	case Opt_uid:
	348	audit_log_format(ab, "uid=%s ", args[0].from);
7b62e162 EP	349
	350	if (entry->uid != -1) {
	351	result = -EINVAL;
	352	break;
	353	}
	354
4af4662f MZ	355	result = strict_strtoul(args[0].from, 10, &lnum);
	356	if (!result) {
	357	entry->uid = (uid_t) lnum;
	358	if (entry->uid != lnum)
	359	result = -EINVAL;
	360	else
	361	entry->flags \|= IMA_UID;
	362	}
	363	break;
	364	case Opt_obj_user:
	365	audit_log_format(ab, "obj_user=%s ", args[0].from);
	366	result = ima_lsm_rule_init(entry, args[0].from,
	367	LSM_OBJ_USER,
	368	AUDIT_OBJ_USER);
	369	break;
	370	case Opt_obj_role:
	371	audit_log_format(ab, "obj_role=%s ", args[0].from);
	372	result = ima_lsm_rule_init(entry, args[0].from,
	373	LSM_OBJ_ROLE,
	374	AUDIT_OBJ_ROLE);
	375	break;
	376	case Opt_obj_type:
	377	audit_log_format(ab, "obj_type=%s ", args[0].from);
	378	result = ima_lsm_rule_init(entry, args[0].from,
	379	LSM_OBJ_TYPE,
	380	AUDIT_OBJ_TYPE);
	381	break;
	382	case Opt_subj_user:
	383	audit_log_format(ab, "subj_user=%s ", args[0].from);
	384	result = ima_lsm_rule_init(entry, args[0].from,
	385	LSM_SUBJ_USER,
	386	AUDIT_SUBJ_USER);
	387	break;
	388	case Opt_subj_role:
	389	audit_log_format(ab, "subj_role=%s ", args[0].from);
	390	result = ima_lsm_rule_init(entry, args[0].from,
	391	LSM_SUBJ_ROLE,
	392	AUDIT_SUBJ_ROLE);
	393	break;
	394	case Opt_subj_type:
	395	audit_log_format(ab, "subj_type=%s ", args[0].from);
	396	result = ima_lsm_rule_init(entry, args[0].from,
	397	LSM_SUBJ_TYPE,
	398	AUDIT_SUBJ_TYPE);
	399	break;
	400	case Opt_err:
e9d393bf	401	result = -EINVAL;
523979ad	402	audit_log_format(ab, "UNKNOWN=%s ", p);
4af4662f MZ	403	break;
	404	}
	405	}
7b62e162	406	if (!result && (entry->action == UNKNOWN))
4af4662f MZ	407	result = -EINVAL;
4af4662f MZ	408
6ccd0456	409	audit_log_format(ab, "res=%d", !!result);
4af4662f MZ	410	audit_log_end(ab);
	411	return result;
	412	}
	413
	414	/**
	415	* ima_parse_add_rule - add a rule to measure_policy_rules
	416	* @rule - ima measurement policy rule
	417	*
	418	* Uses a mutex to protect the policy list from multiple concurrent writers.
6ccd0456	419	* Returns the length of the rule parsed, an error code on failure
4af4662f	420	*/
6ccd0456	421	ssize_t ima_parse_add_rule(char *rule)
4af4662f	422	{
523979ad	423	const char *op = "update_policy";
6ccd0456	424	char *p;
4af4662f	425	struct ima_measure_rule_entry *entry;
6ccd0456	426	ssize_t result, len;
4af4662f MZ	427	int audit_info = 0;
	428
	429	/* Prevent installed policy from changing */
	430	if (ima_measure != &measure_default_rules) {
	431	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
	432	NULL, op, "already exists",
	433	-EACCES, audit_info);
	434	return -EACCES;
	435	}
	436
	437	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	438	if (!entry) {
	439	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
	440	NULL, op, "-ENOMEM", -ENOMEM, audit_info);
	441	return -ENOMEM;
	442	}
	443
	444	INIT_LIST_HEAD(&entry->list);
	445
6ccd0456 EP	446	p = strsep(&rule, "\n");
6ccd0456 EP	447	len = strlen(p) + 1;
7233e3ee EP	448
	449	if (*p == '#') {
	450	kfree(entry);
	451	return len;
	452	}
	453
6ccd0456	454	result = ima_parse_rule(p, entry);
7233e3ee	455	if (result) {
4af4662f	456	kfree(entry);
523979ad MZ	457	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
	458	NULL, op, "invalid policy", result,
	459	audit_info);
7233e3ee	460	return result;
523979ad	461	}
7233e3ee EP	462
	463	mutex_lock(&ima_measure_mutex);
	464	list_add_tail(&entry->list, &measure_policy_rules);
	465	mutex_unlock(&ima_measure_mutex);
	466
	467	return len;
4af4662f MZ	468	}
	469
	470	/* ima_delete_rules called to cleanup invalid policy */
64c61d80	471	void ima_delete_rules(void)
4af4662f MZ	472	{
	473	struct ima_measure_rule_entry entry, tmp;
	474
	475	mutex_lock(&ima_measure_mutex);
	476	list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) {
	477	list_del(&entry->list);
	478	kfree(entry);
	479	}
	480	mutex_unlock(&ima_measure_mutex);
	481	}