1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2008 IBM Corporation
4  * Author: Mimi Zohar <zohar@us.ibm.com>
5  *
6  * ima_policy.c
7  *	- initialize default measure policy rules
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <linux/init.h>
13 #include <linux/list.h>
14 #include <linux/fs.h>
15 #include <linux/security.h>
16 #include <linux/magic.h>
17 #include <linux/parser.h>
18 #include <linux/slab.h>
19 #include <linux/rculist.h>
20 #include <linux/genhd.h>
21 #include <linux/seq_file.h>
22 #include <linux/ima.h>
23 
24 #include "ima.h"
25 
26 /* flags definitions */
27 #define IMA_FUNC	0x0001
28 #define IMA_MASK	0x0002
29 #define IMA_FSMAGIC	0x0004
30 #define IMA_UID		0x0008
31 #define IMA_FOWNER	0x0010
32 #define IMA_FSUUID	0x0020
33 #define IMA_INMASK	0x0040
34 #define IMA_EUID	0x0080
35 #define IMA_PCR		0x0100
36 #define IMA_FSNAME	0x0200
37 
38 #define UNKNOWN		0
39 #define MEASURE		0x0001	/* same as IMA_MEASURE */
40 #define DONT_MEASURE	0x0002
41 #define APPRAISE	0x0004	/* same as IMA_APPRAISE */
42 #define DONT_APPRAISE	0x0008
43 #define AUDIT		0x0040
44 #define HASH		0x0100
45 #define DONT_HASH	0x0200
46 
47 #define INVALID_PCR(a) (((a) < 0) || \
48 	(a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8))
49 
50 int ima_policy_flag;
51 static int temp_ima_appraise;
52 static int build_ima_appraise __ro_after_init;
53 
54 #define MAX_LSM_RULES 6
55 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
56 	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
57 };
58 
59 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
60 
61 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
62 
63 struct ima_rule_entry {
64 	struct list_head list;
65 	int action;
66 	unsigned int flags;
67 	enum ima_hooks func;
68 	int mask;
69 	unsigned long fsmagic;
70 	uuid_t fsuuid;
71 	kuid_t uid;
72 	kuid_t fowner;
73 	bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
74 	bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
75 	int pcr;
76 	struct {
77 		void *rule;	/* LSM file metadata specific */
78 		void *args_p;	/* audit value */
79 		int type;	/* audit type */
80 	} lsm[MAX_LSM_RULES];
81 	char *fsname;
82 	struct ima_template_desc *template;
83 };
84 
85 /*
86  * Without LSM specific knowledge, the default policy can only be
87  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
88  */
89 
90 /*
91  * The minimum rule set to allow for full TCB coverage.  Measures all files
92  * opened or mmap for exec and everything read by root.  Dangerous because
93  * normal users can easily run the machine out of memory simply building
94  * and running executables.
95  */
96 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
97 	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
98 	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
99 	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
100 	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
101 	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
102 	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
103 	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
104 	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
105 	{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
106 	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
107 	 .flags = IMA_FSMAGIC},
108 	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
109 	 .flags = IMA_FSMAGIC},
110 	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
111 	{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
112 };
113 
114 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
115 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
116 	 .flags = IMA_FUNC | IMA_MASK},
117 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
118 	 .flags = IMA_FUNC | IMA_MASK},
119 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
120 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
121 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
122 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
123 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
124 };
125 
126 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
127 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
128 	 .flags = IMA_FUNC | IMA_MASK},
129 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
130 	 .flags = IMA_FUNC | IMA_MASK},
131 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
132 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
133 	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
134 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
135 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
136 	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
137 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
138 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
139 	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
140 };
141 
142 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
143 	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
144 	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
145 	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
146 	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
147 	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
148 	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
149 	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
150 	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
151 	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
152 	{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
153 	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
154 	{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
155 	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
156 	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
157 #ifdef CONFIG_IMA_WRITE_POLICY
158 	{.action = APPRAISE, .func = POLICY_CHECK,
159 	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
160 #endif
161 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
162 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
163 	 .flags = IMA_FOWNER},
164 #else
165 	/* force signature */
166 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
167 	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
168 #endif
169 };
170 
171 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
172 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
173 	{.action = APPRAISE, .func = MODULE_CHECK,
174 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
175 #endif
176 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
177 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
178 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
179 #endif
180 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
181 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
182 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
183 #endif
184 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
185 	{.action = APPRAISE, .func = POLICY_CHECK,
186 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
187 #endif
188 };
189 
190 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
191 	{.action = APPRAISE, .func = MODULE_CHECK,
192 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
193 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
194 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
195 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
196 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
197 	{.action = APPRAISE, .func = POLICY_CHECK,
198 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
199 };
200 
201 /* An array of architecture specific rules */
202 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
203 
204 static LIST_HEAD(ima_default_rules);
205 static LIST_HEAD(ima_policy_rules);
206 static LIST_HEAD(ima_temp_rules);
207 static struct list_head *ima_rules;
208 
209 static int ima_policy __initdata;
210 
211 static int __init default_measure_policy_setup(char *str)
212 {
213 	if (ima_policy)
214 		return 1;
215 
216 	ima_policy = ORIGINAL_TCB;
217 	return 1;
218 }
219 __setup("ima_tcb", default_measure_policy_setup);
220 
221 static bool ima_use_appraise_tcb __initdata;
222 static bool ima_use_secure_boot __initdata;
223 static bool ima_fail_unverifiable_sigs __ro_after_init;
224 static int __init policy_setup(char *str)
225 {
226 	char *p;
227 
228 	while ((p = strsep(&str, " |\n")) != NULL) {
229 		if (*p == ' ')
230 			continue;
231 		if ((strcmp(p, "tcb") == 0) && !ima_policy)
232 			ima_policy = DEFAULT_TCB;
233 		else if (strcmp(p, "appraise_tcb") == 0)
234 			ima_use_appraise_tcb = true;
235 		else if (strcmp(p, "secure_boot") == 0)
236 			ima_use_secure_boot = true;
237 		else if (strcmp(p, "fail_securely") == 0)
238 			ima_fail_unverifiable_sigs = true;
239 	}
240 
241 	return 1;
242 }
243 __setup("ima_policy=", policy_setup);
244 
245 static int __init default_appraise_policy_setup(char *str)
246 {
247 	ima_use_appraise_tcb = true;
248 	return 1;
249 }
250 __setup("ima_appraise_tcb", default_appraise_policy_setup);
251 
252 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
253 {
254 	int i;
255 
256 	for (i = 0; i < MAX_LSM_RULES; i++) {
257 		kfree(entry->lsm[i].rule);
258 		kfree(entry->lsm[i].args_p);
259 	}
260 	kfree(entry);
261 }
262 
263 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
264 {
265 	struct ima_rule_entry *nentry;
266 	int i, result;
267 
268 	nentry = kmalloc(sizeof(*nentry), GFP_KERNEL);
269 	if (!nentry)
270 		return NULL;
271 
272 	/*
273 	 * Immutable elements are copied over as pointers and data; only
274 	 * lsm rules can change
275 	 */
276 	memcpy(nentry, entry, sizeof(*nentry));
277 	memset(nentry->lsm, 0, FIELD_SIZEOF(struct ima_rule_entry, lsm));
278 
279 	for (i = 0; i < MAX_LSM_RULES; i++) {
280 		if (!entry->lsm[i].rule)
281 			continue;
282 
283 		nentry->lsm[i].type = entry->lsm[i].type;
284 		nentry->lsm[i].args_p = kstrdup(entry->lsm[i].args_p,
285 						GFP_KERNEL);
286 		if (!nentry->lsm[i].args_p)
287 			goto out_err;
288 
289 		result = security_filter_rule_init(nentry->lsm[i].type,
290 						   Audit_equal,
291 						   nentry->lsm[i].args_p,
292 						   &nentry->lsm[i].rule);
293 		if (result == -EINVAL)
294 			pr_warn("ima: rule for LSM \'%d\' is undefined\n",
295 				entry->lsm[i].type);
296 	}
297 	return nentry;
298 
299 out_err:
300 	ima_lsm_free_rule(nentry);
301 	return NULL;
302 }
303 
304 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
305 {
306 	struct ima_rule_entry *nentry;
307 
308 	nentry = ima_lsm_copy_rule(entry);
309 	if (!nentry)
310 		return -ENOMEM;
311 
312 	list_replace_rcu(&entry->list, &nentry->list);
313 	synchronize_rcu();
314 	ima_lsm_free_rule(entry);
315 
316 	return 0;
317 }
318 
319 /*
320  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
321  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
322  * the reloaded LSM policy.
323  */
324 static void ima_lsm_update_rules(void)
325 {
326 	struct ima_rule_entry *entry, *e;
327 	int i, result, needs_update;
328 
329 	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
330 		needs_update = 0;
331 		for (i = 0; i < MAX_LSM_RULES; i++) {
332 			if (entry->lsm[i].rule) {
333 				needs_update = 1;
334 				break;
335 			}
336 		}
337 		if (!needs_update)
338 			continue;
339 
340 		result = ima_lsm_update_rule(entry);
341 		if (result) {
342 			pr_err("ima: lsm rule update error %d\n",
343 				result);
344 			return;
345 		}
346 	}
347 }
348 
349 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
350 			  void *lsm_data)
351 {
352 	if (event != LSM_POLICY_CHANGE)
353 		return NOTIFY_DONE;
354 
355 	ima_lsm_update_rules();
356 	return NOTIFY_OK;
357 }
358 
359 /**
360  * ima_match_rules - determine whether an inode matches the measure rule.
361  * @rule: a pointer to a rule
362  * @inode: a pointer to an inode
363  * @cred: a pointer to a credentials structure for user validation
364  * @secid: the secid of the task to be validated
365  * @func: LIM hook identifier
366  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
367  *
368  * Returns true on rule match, false on failure.
369  */
370 static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
371 			    const struct cred *cred, u32 secid,
372 			    enum ima_hooks func, int mask)
373 {
374 	int i;
375 
376 	if (func == KEXEC_CMDLINE) {
377 		if ((rule->flags & IMA_FUNC) && (rule->func == func))
378 			return true;
379 		return false;
380 	}
381 	if ((rule->flags & IMA_FUNC) &&
382 	    (rule->func != func && func != POST_SETATTR))
383 		return false;
384 	if ((rule->flags & IMA_MASK) &&
385 	    (rule->mask != mask && func != POST_SETATTR))
386 		return false;
387 	if ((rule->flags & IMA_INMASK) &&
388 	    (!(rule->mask & mask) && func != POST_SETATTR))
389 		return false;
390 	if ((rule->flags & IMA_FSMAGIC)
391 	    && rule->fsmagic != inode->i_sb->s_magic)
392 		return false;
393 	if ((rule->flags & IMA_FSNAME)
394 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
395 		return false;
396 	if ((rule->flags & IMA_FSUUID) &&
397 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
398 		return false;
399 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
400 		return false;
401 	if (rule->flags & IMA_EUID) {
402 		if (has_capability_noaudit(current, CAP_SETUID)) {
403 			if (!rule->uid_op(cred->euid, rule->uid)
404 			    && !rule->uid_op(cred->suid, rule->uid)
405 			    && !rule->uid_op(cred->uid, rule->uid))
406 				return false;
407 		} else if (!rule->uid_op(cred->euid, rule->uid))
408 			return false;
409 	}
410 
411 	if ((rule->flags & IMA_FOWNER) &&
412 	    !rule->fowner_op(inode->i_uid, rule->fowner))
413 		return false;
414 	for (i = 0; i < MAX_LSM_RULES; i++) {
415 		int rc = 0;
416 		u32 osid;
417 
418 		if (!rule->lsm[i].rule)
419 			continue;
420 
421 		switch (i) {
422 		case LSM_OBJ_USER:
423 		case LSM_OBJ_ROLE:
424 		case LSM_OBJ_TYPE:
425 			security_inode_getsecid(inode, &osid);
426 			rc = security_filter_rule_match(osid,
427 							rule->lsm[i].type,
428 							Audit_equal,
429 							rule->lsm[i].rule);
430 			break;
431 		case LSM_SUBJ_USER:
432 		case LSM_SUBJ_ROLE:
433 		case LSM_SUBJ_TYPE:
434 			rc = security_filter_rule_match(secid,
435 							rule->lsm[i].type,
436 							Audit_equal,
437 							rule->lsm[i].rule);
438 		default:
439 			break;
440 		}
441 		if (!rc)
442 			return false;
443 	}
444 	return true;
445 }
446 
447 /*
448  * In addition to knowing that we need to appraise the file in general,
449  * we need to differentiate between calling hooks, for hook specific rules.
450  */
451 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
452 {
453 	if (!(rule->flags & IMA_FUNC))
454 		return IMA_FILE_APPRAISE;
455 
456 	switch (func) {
457 	case MMAP_CHECK:
458 		return IMA_MMAP_APPRAISE;
459 	case BPRM_CHECK:
460 		return IMA_BPRM_APPRAISE;
461 	case CREDS_CHECK:
462 		return IMA_CREDS_APPRAISE;
463 	case FILE_CHECK:
464 	case POST_SETATTR:
465 		return IMA_FILE_APPRAISE;
466 	case MODULE_CHECK ... MAX_CHECK - 1:
467 	default:
468 		return IMA_READ_APPRAISE;
469 	}
470 }
471 
472 /**
473  * ima_match_policy - decision based on LSM and other conditions
474  * @inode: pointer to an inode for which the policy decision is being made
475  * @cred: pointer to a credentials structure for which the policy decision is
476  *        being made
477  * @secid: LSM secid of the task to be validated
478  * @func: IMA hook identifier
479  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
480  * @pcr: set the pcr to extend
481  * @template_desc: the template that should be used for this rule
482  *
483  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
484  * conditions.
485  *
486  * Since the IMA policy may be updated multiple times we need to lock the
487  * list when walking it.  Reads are many orders of magnitude more numerous
488  * than writes so ima_match_policy() is classical RCU candidate.
489  */
490 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
491 		     enum ima_hooks func, int mask, int flags, int *pcr,
492 		     struct ima_template_desc **template_desc)
493 {
494 	struct ima_rule_entry *entry;
495 	int action = 0, actmask = flags | (flags << 1);
496 
497 	if (template_desc)
498 		*template_desc = ima_template_desc_current();
499 
500 	rcu_read_lock();
501 	list_for_each_entry_rcu(entry, ima_rules, list) {
502 
503 		if (!(entry->action & actmask))
504 			continue;
505 
506 		if (!ima_match_rules(entry, inode, cred, secid, func, mask))
507 			continue;
508 
509 		action |= entry->flags & IMA_ACTION_FLAGS;
510 
511 		action |= entry->action & IMA_DO_MASK;
512 		if (entry->action & IMA_APPRAISE) {
513 			action |= get_subaction(entry, func);
514 			action &= ~IMA_HASH;
515 			if (ima_fail_unverifiable_sigs)
516 				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
517 		}
518 
519 
520 		if (entry->action & IMA_DO_MASK)
521 			actmask &= ~(entry->action | entry->action << 1);
522 		else
523 			actmask &= ~(entry->action | entry->action >> 1);
524 
525 		if ((pcr) && (entry->flags & IMA_PCR))
526 			*pcr = entry->pcr;
527 
528 		if (template_desc && entry->template)
529 			*template_desc = entry->template;
530 
531 		if (!actmask)
532 			break;
533 	}
534 	rcu_read_unlock();
535 
536 	return action;
537 }
538 
539 /*
540  * Initialize the ima_policy_flag variable based on the currently
541  * loaded policy.  Based on this flag, the decision to short circuit
542  * out of a function or not call the function in the first place
543  * can be made earlier.
544  */
545 void ima_update_policy_flag(void)
546 {
547 	struct ima_rule_entry *entry;
548 
549 	list_for_each_entry(entry, ima_rules, list) {
550 		if (entry->action & IMA_DO_MASK)
551 			ima_policy_flag |= entry->action;
552 	}
553 
554 	ima_appraise |= (build_ima_appraise | temp_ima_appraise);
555 	if (!ima_appraise)
556 		ima_policy_flag &= ~IMA_APPRAISE;
557 }
558 
559 static int ima_appraise_flag(enum ima_hooks func)
560 {
561 	if (func == MODULE_CHECK)
562 		return IMA_APPRAISE_MODULES;
563 	else if (func == FIRMWARE_CHECK)
564 		return IMA_APPRAISE_FIRMWARE;
565 	else if (func == POLICY_CHECK)
566 		return IMA_APPRAISE_POLICY;
567 	else if (func == KEXEC_KERNEL_CHECK)
568 		return IMA_APPRAISE_KEXEC;
569 	return 0;
570 }
571 
572 static void add_rules(struct ima_rule_entry *entries, int count,
573 		      enum policy_rule_list policy_rule)
574 {
575 	int i = 0;
576 
577 	for (i = 0; i < count; i++) {
578 		struct ima_rule_entry *entry;
579 
580 		if (policy_rule & IMA_DEFAULT_POLICY)
581 			list_add_tail(&entries[i].list, &ima_default_rules);
582 
583 		if (policy_rule & IMA_CUSTOM_POLICY) {
584 			entry = kmemdup(&entries[i], sizeof(*entry),
585 					GFP_KERNEL);
586 			if (!entry)
587 				continue;
588 
589 			list_add_tail(&entry->list, &ima_policy_rules);
590 		}
591 		if (entries[i].action == APPRAISE) {
592 			temp_ima_appraise |= ima_appraise_flag(entries[i].func);
593 			if (entries[i].func == POLICY_CHECK)
594 				temp_ima_appraise |= IMA_APPRAISE_POLICY;
595 		}
596 	}
597 }
598 
599 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
600 
601 static int __init ima_init_arch_policy(void)
602 {
603 	const char * const *arch_rules;
604 	const char * const *rules;
605 	int arch_entries = 0;
606 	int i = 0;
607 
608 	arch_rules = arch_get_ima_policy();
609 	if (!arch_rules)
610 		return arch_entries;
611 
612 	/* Get number of rules */
613 	for (rules = arch_rules; *rules != NULL; rules++)
614 		arch_entries++;
615 
616 	arch_policy_entry = kcalloc(arch_entries + 1,
617 				    sizeof(*arch_policy_entry), GFP_KERNEL);
618 	if (!arch_policy_entry)
619 		return 0;
620 
621 	/* Convert each policy string rules to struct ima_rule_entry format */
622 	for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
623 		char rule[255];
624 		int result;
625 
626 		result = strlcpy(rule, *rules, sizeof(rule));
627 
628 		INIT_LIST_HEAD(&arch_policy_entry[i].list);
629 		result = ima_parse_rule(rule, &arch_policy_entry[i]);
630 		if (result) {
631 			pr_warn("Skipping unknown architecture policy rule: %s\n",
632 				rule);
633 			memset(&arch_policy_entry[i], 0,
634 			       sizeof(*arch_policy_entry));
635 			continue;
636 		}
637 		i++;
638 	}
639 	return i;
640 }
641 
642 /**
643  * ima_init_policy - initialize the default measure rules.
644  *
645  * ima_rules points to either the ima_default_rules or the
646  * the new ima_policy_rules.
647  */
648 void __init ima_init_policy(void)
649 {
650 	int build_appraise_entries, arch_entries;
651 
652 	/* if !ima_policy, we load NO default rules */
653 	if (ima_policy)
654 		add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
655 			  IMA_DEFAULT_POLICY);
656 
657 	switch (ima_policy) {
658 	case ORIGINAL_TCB:
659 		add_rules(original_measurement_rules,
660 			  ARRAY_SIZE(original_measurement_rules),
661 			  IMA_DEFAULT_POLICY);
662 		break;
663 	case DEFAULT_TCB:
664 		add_rules(default_measurement_rules,
665 			  ARRAY_SIZE(default_measurement_rules),
666 			  IMA_DEFAULT_POLICY);
667 	default:
668 		break;
669 	}
670 
671 	/*
672 	 * Based on runtime secure boot flags, insert arch specific measurement
673 	 * and appraise rules requiring file signatures for both the initial
674 	 * and custom policies, prior to other appraise rules.
675 	 * (Highest priority)
676 	 */
677 	arch_entries = ima_init_arch_policy();
678 	if (!arch_entries)
679 		pr_info("No architecture policies found\n");
680 	else
681 		add_rules(arch_policy_entry, arch_entries,
682 			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
683 
684 	/*
685 	 * Insert the builtin "secure_boot" policy rules requiring file
686 	 * signatures, prior to other appraise rules.
687 	 */
688 	if (ima_use_secure_boot)
689 		add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
690 			  IMA_DEFAULT_POLICY);
691 
692 	/*
693 	 * Insert the build time appraise rules requiring file signatures
694 	 * for both the initial and custom policies, prior to other appraise
695 	 * rules. As the secure boot rules includes all of the build time
696 	 * rules, include either one or the other set of rules, but not both.
697 	 */
698 	build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
699 	if (build_appraise_entries) {
700 		if (ima_use_secure_boot)
701 			add_rules(build_appraise_rules, build_appraise_entries,
702 				  IMA_CUSTOM_POLICY);
703 		else
704 			add_rules(build_appraise_rules, build_appraise_entries,
705 				  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
706 	}
707 
708 	if (ima_use_appraise_tcb)
709 		add_rules(default_appraise_rules,
710 			  ARRAY_SIZE(default_appraise_rules),
711 			  IMA_DEFAULT_POLICY);
712 
713 	ima_rules = &ima_default_rules;
714 	ima_update_policy_flag();
715 }
716 
717 /* Make sure we have a valid policy, at least containing some rules. */
718 int ima_check_policy(void)
719 {
720 	if (list_empty(&ima_temp_rules))
721 		return -EINVAL;
722 	return 0;
723 }
724 
725 /**
726  * ima_update_policy - update default_rules with new measure rules
727  *
728  * Called on file .release to update the default rules with a complete new
729  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
730  * they make a queue.  The policy may be updated multiple times and this is the
731  * RCU updater.
732  *
733  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
734  * we switch from the default policy to user defined.
735  */
736 void ima_update_policy(void)
737 {
738 	struct list_head *policy = &ima_policy_rules;
739 
740 	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
741 
742 	if (ima_rules != policy) {
743 		ima_policy_flag = 0;
744 		ima_rules = policy;
745 
746 		/*
747 		 * IMA architecture specific policy rules are specified
748 		 * as strings and converted to an array of ima_entry_rules
749 		 * on boot.  After loading a custom policy, free the
750 		 * architecture specific rules stored as an array.
751 		 */
752 		kfree(arch_policy_entry);
753 	}
754 	ima_update_policy_flag();
755 }
756 
757 /* Keep the enumeration in sync with the policy_tokens! */
758 enum {
759 	Opt_measure, Opt_dont_measure,
760 	Opt_appraise, Opt_dont_appraise,
761 	Opt_audit, Opt_hash, Opt_dont_hash,
762 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
763 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
764 	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
765 	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
766 	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
767 	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
768 	Opt_appraise_type, Opt_appraise_flag,
769 	Opt_permit_directio, Opt_pcr, Opt_template, Opt_err
770 };
771 
772 static const match_table_t policy_tokens = {
773 	{Opt_measure, "measure"},
774 	{Opt_dont_measure, "dont_measure"},
775 	{Opt_appraise, "appraise"},
776 	{Opt_dont_appraise, "dont_appraise"},
777 	{Opt_audit, "audit"},
778 	{Opt_hash, "hash"},
779 	{Opt_dont_hash, "dont_hash"},
780 	{Opt_obj_user, "obj_user=%s"},
781 	{Opt_obj_role, "obj_role=%s"},
782 	{Opt_obj_type, "obj_type=%s"},
783 	{Opt_subj_user, "subj_user=%s"},
784 	{Opt_subj_role, "subj_role=%s"},
785 	{Opt_subj_type, "subj_type=%s"},
786 	{Opt_func, "func=%s"},
787 	{Opt_mask, "mask=%s"},
788 	{Opt_fsmagic, "fsmagic=%s"},
789 	{Opt_fsname, "fsname=%s"},
790 	{Opt_fsuuid, "fsuuid=%s"},
791 	{Opt_uid_eq, "uid=%s"},
792 	{Opt_euid_eq, "euid=%s"},
793 	{Opt_fowner_eq, "fowner=%s"},
794 	{Opt_uid_gt, "uid>%s"},
795 	{Opt_euid_gt, "euid>%s"},
796 	{Opt_fowner_gt, "fowner>%s"},
797 	{Opt_uid_lt, "uid<%s"},
798 	{Opt_euid_lt, "euid<%s"},
799 	{Opt_fowner_lt, "fowner<%s"},
800 	{Opt_appraise_type, "appraise_type=%s"},
801 	{Opt_appraise_flag, "appraise_flag=%s"},
802 	{Opt_permit_directio, "permit_directio"},
803 	{Opt_pcr, "pcr=%s"},
804 	{Opt_template, "template=%s"},
805 	{Opt_err, NULL}
806 };
807 
808 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
809 			     substring_t *args, int lsm_rule, int audit_type)
810 {
811 	int result;
812 
813 	if (entry->lsm[lsm_rule].rule)
814 		return -EINVAL;
815 
816 	entry->lsm[lsm_rule].args_p = match_strdup(args);
817 	if (!entry->lsm[lsm_rule].args_p)
818 		return -ENOMEM;
819 
820 	entry->lsm[lsm_rule].type = audit_type;
821 	result = security_filter_rule_init(entry->lsm[lsm_rule].type,
822 					   Audit_equal,
823 					   entry->lsm[lsm_rule].args_p,
824 					   &entry->lsm[lsm_rule].rule);
825 	if (!entry->lsm[lsm_rule].rule) {
826 		kfree(entry->lsm[lsm_rule].args_p);
827 		return -EINVAL;
828 	}
829 
830 	return result;
831 }
832 
833 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
834 			      bool (*rule_operator)(kuid_t, kuid_t))
835 {
836 	if (!ab)
837 		return;
838 
839 	if (rule_operator == &uid_gt)
840 		audit_log_format(ab, "%s>", key);
841 	else if (rule_operator == &uid_lt)
842 		audit_log_format(ab, "%s<", key);
843 	else
844 		audit_log_format(ab, "%s=", key);
845 	audit_log_format(ab, "%s ", value);
846 }
847 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
848 {
849 	ima_log_string_op(ab, key, value, NULL);
850 }
851 
852 /*
853  * Validating the appended signature included in the measurement list requires
854  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
855  * field). Therefore, notify the user if they have the 'modsig' field but not
856  * the 'd-modsig' field in the template.
857  */
858 static void check_template_modsig(const struct ima_template_desc *template)
859 {
860 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
861 	bool has_modsig, has_dmodsig;
862 	static bool checked;
863 	int i;
864 
865 	/* We only need to notify the user once. */
866 	if (checked)
867 		return;
868 
869 	has_modsig = has_dmodsig = false;
870 	for (i = 0; i < template->num_fields; i++) {
871 		if (!strcmp(template->fields[i]->field_id, "modsig"))
872 			has_modsig = true;
873 		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
874 			has_dmodsig = true;
875 	}
876 
877 	if (has_modsig && !has_dmodsig)
878 		pr_notice(MSG);
879 
880 	checked = true;
881 #undef MSG
882 }
883 
884 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
885 {
886 	struct audit_buffer *ab;
887 	char *from;
888 	char *p;
889 	bool uid_token;
890 	struct ima_template_desc *template_desc;
891 	int result = 0;
892 
893 	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
894 				       AUDIT_INTEGRITY_POLICY_RULE);
895 
896 	entry->uid = INVALID_UID;
897 	entry->fowner = INVALID_UID;
898 	entry->uid_op = &uid_eq;
899 	entry->fowner_op = &uid_eq;
900 	entry->action = UNKNOWN;
901 	while ((p = strsep(&rule, " \t")) != NULL) {
902 		substring_t args[MAX_OPT_ARGS];
903 		int token;
904 		unsigned long lnum;
905 
906 		if (result < 0)
907 			break;
908 		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
909 			continue;
910 		token = match_token(p, policy_tokens, args);
911 		switch (token) {
912 		case Opt_measure:
913 			ima_log_string(ab, "action", "measure");
914 
915 			if (entry->action != UNKNOWN)
916 				result = -EINVAL;
917 
918 			entry->action = MEASURE;
919 			break;
920 		case Opt_dont_measure:
921 			ima_log_string(ab, "action", "dont_measure");
922 
923 			if (entry->action != UNKNOWN)
924 				result = -EINVAL;
925 
926 			entry->action = DONT_MEASURE;
927 			break;
928 		case Opt_appraise:
929 			ima_log_string(ab, "action", "appraise");
930 
931 			if (entry->action != UNKNOWN)
932 				result = -EINVAL;
933 
934 			entry->action = APPRAISE;
935 			break;
936 		case Opt_dont_appraise:
937 			ima_log_string(ab, "action", "dont_appraise");
938 
939 			if (entry->action != UNKNOWN)
940 				result = -EINVAL;
941 
942 			entry->action = DONT_APPRAISE;
943 			break;
944 		case Opt_audit:
945 			ima_log_string(ab, "action", "audit");
946 
947 			if (entry->action != UNKNOWN)
948 				result = -EINVAL;
949 
950 			entry->action = AUDIT;
951 			break;
952 		case Opt_hash:
953 			ima_log_string(ab, "action", "hash");
954 
955 			if (entry->action != UNKNOWN)
956 				result = -EINVAL;
957 
958 			entry->action = HASH;
959 			break;
960 		case Opt_dont_hash:
961 			ima_log_string(ab, "action", "dont_hash");
962 
963 			if (entry->action != UNKNOWN)
964 				result = -EINVAL;
965 
966 			entry->action = DONT_HASH;
967 			break;
968 		case Opt_func:
969 			ima_log_string(ab, "func", args[0].from);
970 
971 			if (entry->func)
972 				result = -EINVAL;
973 
974 			if (strcmp(args[0].from, "FILE_CHECK") == 0)
975 				entry->func = FILE_CHECK;
976 			/* PATH_CHECK is for backwards compat */
977 			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
978 				entry->func = FILE_CHECK;
979 			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
980 				entry->func = MODULE_CHECK;
981 			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
982 				entry->func = FIRMWARE_CHECK;
983 			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
984 				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
985 				entry->func = MMAP_CHECK;
986 			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
987 				entry->func = BPRM_CHECK;
988 			else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
989 				entry->func = CREDS_CHECK;
990 			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
991 				 0)
992 				entry->func = KEXEC_KERNEL_CHECK;
993 			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
994 				 == 0)
995 				entry->func = KEXEC_INITRAMFS_CHECK;
996 			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
997 				entry->func = POLICY_CHECK;
998 			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
999 				entry->func = KEXEC_CMDLINE;
1000 			else
1001 				result = -EINVAL;
1002 			if (!result)
1003 				entry->flags |= IMA_FUNC;
1004 			break;
1005 		case Opt_mask:
1006 			ima_log_string(ab, "mask", args[0].from);
1007 
1008 			if (entry->mask)
1009 				result = -EINVAL;
1010 
1011 			from = args[0].from;
1012 			if (*from == '^')
1013 				from++;
1014 
1015 			if ((strcmp(from, "MAY_EXEC")) == 0)
1016 				entry->mask = MAY_EXEC;
1017 			else if (strcmp(from, "MAY_WRITE") == 0)
1018 				entry->mask = MAY_WRITE;
1019 			else if (strcmp(from, "MAY_READ") == 0)
1020 				entry->mask = MAY_READ;
1021 			else if (strcmp(from, "MAY_APPEND") == 0)
1022 				entry->mask = MAY_APPEND;
1023 			else
1024 				result = -EINVAL;
1025 			if (!result)
1026 				entry->flags |= (*args[0].from == '^')
1027 				     ? IMA_INMASK : IMA_MASK;
1028 			break;
1029 		case Opt_fsmagic:
1030 			ima_log_string(ab, "fsmagic", args[0].from);
1031 
1032 			if (entry->fsmagic) {
1033 				result = -EINVAL;
1034 				break;
1035 			}
1036 
1037 			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1038 			if (!result)
1039 				entry->flags |= IMA_FSMAGIC;
1040 			break;
1041 		case Opt_fsname:
1042 			ima_log_string(ab, "fsname", args[0].from);
1043 
1044 			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1045 			if (!entry->fsname) {
1046 				result = -ENOMEM;
1047 				break;
1048 			}
1049 			result = 0;
1050 			entry->flags |= IMA_FSNAME;
1051 			break;
1052 		case Opt_fsuuid:
1053 			ima_log_string(ab, "fsuuid", args[0].from);
1054 
1055 			if (!uuid_is_null(&entry->fsuuid)) {
1056 				result = -EINVAL;
1057 				break;
1058 			}
1059 
1060 			result = uuid_parse(args[0].from, &entry->fsuuid);
1061 			if (!result)
1062 				entry->flags |= IMA_FSUUID;
1063 			break;
1064 		case Opt_uid_gt:
1065 		case Opt_euid_gt:
1066 			entry->uid_op = &uid_gt;
1067 			/* fall through */
1068 		case Opt_uid_lt:
1069 		case Opt_euid_lt:
1070 			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1071 				entry->uid_op = &uid_lt;
1072 			/* fall through */
1073 		case Opt_uid_eq:
1074 		case Opt_euid_eq:
1075 			uid_token = (token == Opt_uid_eq) ||
1076 				    (token == Opt_uid_gt) ||
1077 				    (token == Opt_uid_lt);
1078 
1079 			ima_log_string_op(ab, uid_token ? "uid" : "euid",
1080 					  args[0].from, entry->uid_op);
1081 
1082 			if (uid_valid(entry->uid)) {
1083 				result = -EINVAL;
1084 				break;
1085 			}
1086 
1087 			result = kstrtoul(args[0].from, 10, &lnum);
1088 			if (!result) {
1089 				entry->uid = make_kuid(current_user_ns(),
1090 						       (uid_t) lnum);
1091 				if (!uid_valid(entry->uid) ||
1092 				    (uid_t)lnum != lnum)
1093 					result = -EINVAL;
1094 				else
1095 					entry->flags |= uid_token
1096 					    ? IMA_UID : IMA_EUID;
1097 			}
1098 			break;
1099 		case Opt_fowner_gt:
1100 			entry->fowner_op = &uid_gt;
1101 			/* fall through */
1102 		case Opt_fowner_lt:
1103 			if (token == Opt_fowner_lt)
1104 				entry->fowner_op = &uid_lt;
1105 			/* fall through */
1106 		case Opt_fowner_eq:
1107 			ima_log_string_op(ab, "fowner", args[0].from,
1108 					  entry->fowner_op);
1109 
1110 			if (uid_valid(entry->fowner)) {
1111 				result = -EINVAL;
1112 				break;
1113 			}
1114 
1115 			result = kstrtoul(args[0].from, 10, &lnum);
1116 			if (!result) {
1117 				entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
1118 				if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
1119 					result = -EINVAL;
1120 				else
1121 					entry->flags |= IMA_FOWNER;
1122 			}
1123 			break;
1124 		case Opt_obj_user:
1125 			ima_log_string(ab, "obj_user", args[0].from);
1126 			result = ima_lsm_rule_init(entry, args,
1127 						   LSM_OBJ_USER,
1128 						   AUDIT_OBJ_USER);
1129 			break;
1130 		case Opt_obj_role:
1131 			ima_log_string(ab, "obj_role", args[0].from);
1132 			result = ima_lsm_rule_init(entry, args,
1133 						   LSM_OBJ_ROLE,
1134 						   AUDIT_OBJ_ROLE);
1135 			break;
1136 		case Opt_obj_type:
1137 			ima_log_string(ab, "obj_type", args[0].from);
1138 			result = ima_lsm_rule_init(entry, args,
1139 						   LSM_OBJ_TYPE,
1140 						   AUDIT_OBJ_TYPE);
1141 			break;
1142 		case Opt_subj_user:
1143 			ima_log_string(ab, "subj_user", args[0].from);
1144 			result = ima_lsm_rule_init(entry, args,
1145 						   LSM_SUBJ_USER,
1146 						   AUDIT_SUBJ_USER);
1147 			break;
1148 		case Opt_subj_role:
1149 			ima_log_string(ab, "subj_role", args[0].from);
1150 			result = ima_lsm_rule_init(entry, args,
1151 						   LSM_SUBJ_ROLE,
1152 						   AUDIT_SUBJ_ROLE);
1153 			break;
1154 		case Opt_subj_type:
1155 			ima_log_string(ab, "subj_type", args[0].from);
1156 			result = ima_lsm_rule_init(entry, args,
1157 						   LSM_SUBJ_TYPE,
1158 						   AUDIT_SUBJ_TYPE);
1159 			break;
1160 		case Opt_appraise_type:
1161 			if (entry->action != APPRAISE) {
1162 				result = -EINVAL;
1163 				break;
1164 			}
1165 
1166 			ima_log_string(ab, "appraise_type", args[0].from);
1167 			if ((strcmp(args[0].from, "imasig")) == 0)
1168 				entry->flags |= IMA_DIGSIG_REQUIRED;
1169 			else if (ima_hook_supports_modsig(entry->func) &&
1170 				 strcmp(args[0].from, "imasig|modsig") == 0)
1171 				entry->flags |= IMA_DIGSIG_REQUIRED |
1172 						IMA_MODSIG_ALLOWED;
1173 			else
1174 				result = -EINVAL;
1175 			break;
1176 		case Opt_appraise_flag:
1177 			ima_log_string(ab, "appraise_flag", args[0].from);
1178 			if (strstr(args[0].from, "blacklist"))
1179 				entry->flags |= IMA_CHECK_BLACKLIST;
1180 			break;
1181 		case Opt_permit_directio:
1182 			entry->flags |= IMA_PERMIT_DIRECTIO;
1183 			break;
1184 		case Opt_pcr:
1185 			if (entry->action != MEASURE) {
1186 				result = -EINVAL;
1187 				break;
1188 			}
1189 			ima_log_string(ab, "pcr", args[0].from);
1190 
1191 			result = kstrtoint(args[0].from, 10, &entry->pcr);
1192 			if (result || INVALID_PCR(entry->pcr))
1193 				result = -EINVAL;
1194 			else
1195 				entry->flags |= IMA_PCR;
1196 
1197 			break;
1198 		case Opt_template:
1199 			ima_log_string(ab, "template", args[0].from);
1200 			if (entry->action != MEASURE) {
1201 				result = -EINVAL;
1202 				break;
1203 			}
1204 			template_desc = lookup_template_desc(args[0].from);
1205 			if (!template_desc || entry->template) {
1206 				result = -EINVAL;
1207 				break;
1208 			}
1209 
1210 			/*
1211 			 * template_desc_init_fields() does nothing if
1212 			 * the template is already initialised, so
1213 			 * it's safe to do this unconditionally
1214 			 */
1215 			template_desc_init_fields(template_desc->fmt,
1216 						 &(template_desc->fields),
1217 						 &(template_desc->num_fields));
1218 			entry->template = template_desc;
1219 			break;
1220 		case Opt_err:
1221 			ima_log_string(ab, "UNKNOWN", p);
1222 			result = -EINVAL;
1223 			break;
1224 		}
1225 	}
1226 	if (!result && (entry->action == UNKNOWN))
1227 		result = -EINVAL;
1228 	else if (entry->action == APPRAISE)
1229 		temp_ima_appraise |= ima_appraise_flag(entry->func);
1230 
1231 	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1232 		template_desc = entry->template ? entry->template :
1233 						  ima_template_desc_current();
1234 		check_template_modsig(template_desc);
1235 	}
1236 
1237 	audit_log_format(ab, "res=%d", !result);
1238 	audit_log_end(ab);
1239 	return result;
1240 }
1241 
1242 /**
1243  * ima_parse_add_rule - add a rule to ima_policy_rules
1244  * @rule - ima measurement policy rule
1245  *
1246  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1247  * Returns the length of the rule parsed, an error code on failure
1248  */
1249 ssize_t ima_parse_add_rule(char *rule)
1250 {
1251 	static const char op[] = "update_policy";
1252 	char *p;
1253 	struct ima_rule_entry *entry;
1254 	ssize_t result, len;
1255 	int audit_info = 0;
1256 
1257 	p = strsep(&rule, "\n");
1258 	len = strlen(p) + 1;
1259 	p += strspn(p, " \t");
1260 
1261 	if (*p == '#' || *p == '\0')
1262 		return len;
1263 
1264 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1265 	if (!entry) {
1266 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1267 				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1268 		return -ENOMEM;
1269 	}
1270 
1271 	INIT_LIST_HEAD(&entry->list);
1272 
1273 	result = ima_parse_rule(p, entry);
1274 	if (result) {
1275 		kfree(entry);
1276 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1277 				    NULL, op, "invalid-policy", result,
1278 				    audit_info);
1279 		return result;
1280 	}
1281 
1282 	list_add_tail(&entry->list, &ima_temp_rules);
1283 
1284 	return len;
1285 }
1286 
1287 /**
1288  * ima_delete_rules() called to cleanup invalid in-flight policy.
1289  * We don't need locking as we operate on the temp list, which is
1290  * different from the active one.  There is also only one user of
1291  * ima_delete_rules() at a time.
1292  */
1293 void ima_delete_rules(void)
1294 {
1295 	struct ima_rule_entry *entry, *tmp;
1296 	int i;
1297 
1298 	temp_ima_appraise = 0;
1299 	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1300 		for (i = 0; i < MAX_LSM_RULES; i++)
1301 			kfree(entry->lsm[i].args_p);
1302 
1303 		list_del(&entry->list);
1304 		kfree(entry);
1305 	}
1306 }
1307 
1308 #define __ima_hook_stringify(str)	(#str),
1309 
1310 const char *const func_tokens[] = {
1311 	__ima_hooks(__ima_hook_stringify)
1312 };
1313 
1314 #ifdef	CONFIG_IMA_READ_POLICY
1315 enum {
1316 	mask_exec = 0, mask_write, mask_read, mask_append
1317 };
1318 
1319 static const char *const mask_tokens[] = {
1320 	"^MAY_EXEC",
1321 	"^MAY_WRITE",
1322 	"^MAY_READ",
1323 	"^MAY_APPEND"
1324 };
1325 
1326 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1327 {
1328 	loff_t l = *pos;
1329 	struct ima_rule_entry *entry;
1330 
1331 	rcu_read_lock();
1332 	list_for_each_entry_rcu(entry, ima_rules, list) {
1333 		if (!l--) {
1334 			rcu_read_unlock();
1335 			return entry;
1336 		}
1337 	}
1338 	rcu_read_unlock();
1339 	return NULL;
1340 }
1341 
1342 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1343 {
1344 	struct ima_rule_entry *entry = v;
1345 
1346 	rcu_read_lock();
1347 	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1348 	rcu_read_unlock();
1349 	(*pos)++;
1350 
1351 	return (&entry->list == ima_rules) ? NULL : entry;
1352 }
1353 
1354 void ima_policy_stop(struct seq_file *m, void *v)
1355 {
1356 }
1357 
1358 #define pt(token)	policy_tokens[token].pattern
1359 #define mt(token)	mask_tokens[token]
1360 
1361 /*
1362  * policy_func_show - display the ima_hooks policy rule
1363  */
1364 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1365 {
1366 	if (func > 0 && func < MAX_CHECK)
1367 		seq_printf(m, "func=%s ", func_tokens[func]);
1368 	else
1369 		seq_printf(m, "func=%d ", func);
1370 }
1371 
1372 int ima_policy_show(struct seq_file *m, void *v)
1373 {
1374 	struct ima_rule_entry *entry = v;
1375 	int i;
1376 	char tbuf[64] = {0,};
1377 	int offset = 0;
1378 
1379 	rcu_read_lock();
1380 
1381 	if (entry->action & MEASURE)
1382 		seq_puts(m, pt(Opt_measure));
1383 	if (entry->action & DONT_MEASURE)
1384 		seq_puts(m, pt(Opt_dont_measure));
1385 	if (entry->action & APPRAISE)
1386 		seq_puts(m, pt(Opt_appraise));
1387 	if (entry->action & DONT_APPRAISE)
1388 		seq_puts(m, pt(Opt_dont_appraise));
1389 	if (entry->action & AUDIT)
1390 		seq_puts(m, pt(Opt_audit));
1391 	if (entry->action & HASH)
1392 		seq_puts(m, pt(Opt_hash));
1393 	if (entry->action & DONT_HASH)
1394 		seq_puts(m, pt(Opt_dont_hash));
1395 
1396 	seq_puts(m, " ");
1397 
1398 	if (entry->flags & IMA_FUNC)
1399 		policy_func_show(m, entry->func);
1400 
1401 	if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1402 		if (entry->flags & IMA_MASK)
1403 			offset = 1;
1404 		if (entry->mask & MAY_EXEC)
1405 			seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
1406 		if (entry->mask & MAY_WRITE)
1407 			seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
1408 		if (entry->mask & MAY_READ)
1409 			seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
1410 		if (entry->mask & MAY_APPEND)
1411 			seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
1412 		seq_puts(m, " ");
1413 	}
1414 
1415 	if (entry->flags & IMA_FSMAGIC) {
1416 		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
1417 		seq_printf(m, pt(Opt_fsmagic), tbuf);
1418 		seq_puts(m, " ");
1419 	}
1420 
1421 	if (entry->flags & IMA_FSNAME) {
1422 		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
1423 		seq_printf(m, pt(Opt_fsname), tbuf);
1424 		seq_puts(m, " ");
1425 	}
1426 
1427 	if (entry->flags & IMA_PCR) {
1428 		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
1429 		seq_printf(m, pt(Opt_pcr), tbuf);
1430 		seq_puts(m, " ");
1431 	}
1432 
1433 	if (entry->flags & IMA_FSUUID) {
1434 		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
1435 		seq_puts(m, " ");
1436 	}
1437 
1438 	if (entry->flags & IMA_UID) {
1439 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1440 		if (entry->uid_op == &uid_gt)
1441 			seq_printf(m, pt(Opt_uid_gt), tbuf);
1442 		else if (entry->uid_op == &uid_lt)
1443 			seq_printf(m, pt(Opt_uid_lt), tbuf);
1444 		else
1445 			seq_printf(m, pt(Opt_uid_eq), tbuf);
1446 		seq_puts(m, " ");
1447 	}
1448 
1449 	if (entry->flags & IMA_EUID) {
1450 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1451 		if (entry->uid_op == &uid_gt)
1452 			seq_printf(m, pt(Opt_euid_gt), tbuf);
1453 		else if (entry->uid_op == &uid_lt)
1454 			seq_printf(m, pt(Opt_euid_lt), tbuf);
1455 		else
1456 			seq_printf(m, pt(Opt_euid_eq), tbuf);
1457 		seq_puts(m, " ");
1458 	}
1459 
1460 	if (entry->flags & IMA_FOWNER) {
1461 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
1462 		if (entry->fowner_op == &uid_gt)
1463 			seq_printf(m, pt(Opt_fowner_gt), tbuf);
1464 		else if (entry->fowner_op == &uid_lt)
1465 			seq_printf(m, pt(Opt_fowner_lt), tbuf);
1466 		else
1467 			seq_printf(m, pt(Opt_fowner_eq), tbuf);
1468 		seq_puts(m, " ");
1469 	}
1470 
1471 	for (i = 0; i < MAX_LSM_RULES; i++) {
1472 		if (entry->lsm[i].rule) {
1473 			switch (i) {
1474 			case LSM_OBJ_USER:
1475 				seq_printf(m, pt(Opt_obj_user),
1476 					   (char *)entry->lsm[i].args_p);
1477 				break;
1478 			case LSM_OBJ_ROLE:
1479 				seq_printf(m, pt(Opt_obj_role),
1480 					   (char *)entry->lsm[i].args_p);
1481 				break;
1482 			case LSM_OBJ_TYPE:
1483 				seq_printf(m, pt(Opt_obj_type),
1484 					   (char *)entry->lsm[i].args_p);
1485 				break;
1486 			case LSM_SUBJ_USER:
1487 				seq_printf(m, pt(Opt_subj_user),
1488 					   (char *)entry->lsm[i].args_p);
1489 				break;
1490 			case LSM_SUBJ_ROLE:
1491 				seq_printf(m, pt(Opt_subj_role),
1492 					   (char *)entry->lsm[i].args_p);
1493 				break;
1494 			case LSM_SUBJ_TYPE:
1495 				seq_printf(m, pt(Opt_subj_type),
1496 					   (char *)entry->lsm[i].args_p);
1497 				break;
1498 			}
1499 		}
1500 	}
1501 	if (entry->template)
1502 		seq_printf(m, "template=%s ", entry->template->name);
1503 	if (entry->flags & IMA_DIGSIG_REQUIRED) {
1504 		if (entry->flags & IMA_MODSIG_ALLOWED)
1505 			seq_puts(m, "appraise_type=imasig|modsig ");
1506 		else
1507 			seq_puts(m, "appraise_type=imasig ");
1508 	}
1509 	if (entry->flags & IMA_CHECK_BLACKLIST)
1510 		seq_puts(m, "appraise_flag=check_blacklist ");
1511 	if (entry->flags & IMA_PERMIT_DIRECTIO)
1512 		seq_puts(m, "permit_directio ");
1513 	rcu_read_unlock();
1514 	seq_puts(m, "\n");
1515 	return 0;
1516 }
1517 #endif	/* CONFIG_IMA_READ_POLICY */
1518 
1519 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
1520 /*
1521  * ima_appraise_signature: whether IMA will appraise a given function using
1522  * an IMA digital signature. This is restricted to cases where the kernel
1523  * has a set of built-in trusted keys in order to avoid an attacker simply
1524  * loading additional keys.
1525  */
1526 bool ima_appraise_signature(enum kernel_read_file_id id)
1527 {
1528 	struct ima_rule_entry *entry;
1529 	bool found = false;
1530 	enum ima_hooks func;
1531 
1532 	if (id >= READING_MAX_ID)
1533 		return false;
1534 
1535 	func = read_idmap[id] ?: FILE_CHECK;
1536 
1537 	rcu_read_lock();
1538 	list_for_each_entry_rcu(entry, ima_rules, list) {
1539 		if (entry->action != APPRAISE)
1540 			continue;
1541 
1542 		/*
1543 		 * A generic entry will match, but otherwise require that it
1544 		 * match the func we're looking for
1545 		 */
1546 		if (entry->func && entry->func != func)
1547 			continue;
1548 
1549 		/*
1550 		 * We require this to be a digital signature, not a raw IMA
1551 		 * hash.
1552 		 */
1553 		if (entry->flags & IMA_DIGSIG_REQUIRED)
1554 			found = true;
1555 
1556 		/*
1557 		 * We've found a rule that matches, so break now even if it
1558 		 * didn't require a digital signature - a later rule that does
1559 		 * won't override it, so would be a false positive.
1560 		 */
1561 		break;
1562 	}
1563 
1564 	rcu_read_unlock();
1565 	return found;
1566 }
1567 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
1568