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 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/kernel_read_file.h>
13 #include <linux/fs.h>
14 #include <linux/security.h>
15 #include <linux/magic.h>
16 #include <linux/parser.h>
17 #include <linux/slab.h>
18 #include <linux/rculist.h>
19 #include <linux/genhd.h>
20 #include <linux/seq_file.h>
21 #include <linux/ima.h>
22 
23 #include "ima.h"
24 
25 /* flags definitions */
26 #define IMA_FUNC	0x0001
27 #define IMA_MASK	0x0002
28 #define IMA_FSMAGIC	0x0004
29 #define IMA_UID		0x0008
30 #define IMA_FOWNER	0x0010
31 #define IMA_FSUUID	0x0020
32 #define IMA_INMASK	0x0040
33 #define IMA_EUID	0x0080
34 #define IMA_PCR		0x0100
35 #define IMA_FSNAME	0x0200
36 #define IMA_KEYRINGS	0x0400
37 #define IMA_LABEL	0x0800
38 #define IMA_VALIDATE_ALGOS	0x1000
39 #define IMA_GID		0x2000
40 #define IMA_EGID	0x4000
41 #define IMA_FGROUP	0x8000
42 
43 #define UNKNOWN		0
44 #define MEASURE		0x0001	/* same as IMA_MEASURE */
45 #define DONT_MEASURE	0x0002
46 #define APPRAISE	0x0004	/* same as IMA_APPRAISE */
47 #define DONT_APPRAISE	0x0008
48 #define AUDIT		0x0040
49 #define HASH		0x0100
50 #define DONT_HASH	0x0200
51 
52 #define INVALID_PCR(a) (((a) < 0) || \
53 	(a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
54 
55 int ima_policy_flag;
56 static int temp_ima_appraise;
57 static int build_ima_appraise __ro_after_init;
58 
59 atomic_t ima_setxattr_allowed_hash_algorithms;
60 
61 #define MAX_LSM_RULES 6
62 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
63 	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
64 };
65 
66 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
67 
68 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
69 
70 struct ima_rule_opt_list {
71 	size_t count;
72 	char *items[];
73 };
74 
75 struct ima_rule_entry {
76 	struct list_head list;
77 	int action;
78 	unsigned int flags;
79 	enum ima_hooks func;
80 	int mask;
81 	unsigned long fsmagic;
82 	uuid_t fsuuid;
83 	kuid_t uid;
84 	kgid_t gid;
85 	kuid_t fowner;
86 	kgid_t fgroup;
87 	bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
88 	bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
89 	bool (*fowner_op)(kuid_t cred_uid, kuid_t rule_uid); /* uid_eq(), uid_gt(), uid_lt() */
90 	bool (*fgroup_op)(kgid_t cred_gid, kgid_t rule_gid); /* gid_eq(), gid_gt(), gid_lt() */
91 	int pcr;
92 	unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
93 	struct {
94 		void *rule;	/* LSM file metadata specific */
95 		char *args_p;	/* audit value */
96 		int type;	/* audit type */
97 	} lsm[MAX_LSM_RULES];
98 	char *fsname;
99 	struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
100 	struct ima_rule_opt_list *label; /* Measure data grouped under this label */
101 	struct ima_template_desc *template;
102 };
103 
104 /*
105  * sanity check in case the kernels gains more hash algorithms that can
106  * fit in an unsigned int
107  */
108 static_assert(
109 	8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
110 	"The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
111 
112 /*
113  * Without LSM specific knowledge, the default policy can only be
114  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
115  * .fowner, and .fgroup
116  */
117 
118 /*
119  * The minimum rule set to allow for full TCB coverage.  Measures all files
120  * opened or mmap for exec and everything read by root.  Dangerous because
121  * normal users can easily run the machine out of memory simply building
122  * and running executables.
123  */
124 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
125 	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
126 	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
127 	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
128 	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
129 	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
130 	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
131 	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
132 	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
133 	{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
134 	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
135 	 .flags = IMA_FSMAGIC},
136 	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
137 	 .flags = IMA_FSMAGIC},
138 	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
139 	{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
140 };
141 
142 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
143 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
144 	 .flags = IMA_FUNC | IMA_MASK},
145 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
146 	 .flags = IMA_FUNC | IMA_MASK},
147 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
148 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
149 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
150 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
151 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
152 };
153 
154 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
155 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
156 	 .flags = IMA_FUNC | IMA_MASK},
157 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
158 	 .flags = IMA_FUNC | IMA_MASK},
159 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
160 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
161 	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
162 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
163 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
164 	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
165 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
166 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
167 	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
168 };
169 
170 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
171 	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
172 	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
173 	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
174 	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
175 	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
176 	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
177 	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
178 	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
179 	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
180 	{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
181 	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
182 	{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
183 	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
184 	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
185 #ifdef CONFIG_IMA_WRITE_POLICY
186 	{.action = APPRAISE, .func = POLICY_CHECK,
187 	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
188 #endif
189 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
190 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
191 	 .flags = IMA_FOWNER},
192 #else
193 	/* force signature */
194 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
195 	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
196 #endif
197 };
198 
199 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
200 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
201 	{.action = APPRAISE, .func = MODULE_CHECK,
202 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
203 #endif
204 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
205 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
206 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
207 #endif
208 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
209 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
210 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
211 #endif
212 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
213 	{.action = APPRAISE, .func = POLICY_CHECK,
214 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
215 #endif
216 };
217 
218 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
219 	{.action = APPRAISE, .func = MODULE_CHECK,
220 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
221 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
222 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
223 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
224 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
225 	{.action = APPRAISE, .func = POLICY_CHECK,
226 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
227 };
228 
229 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
230 	{.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
231 };
232 
233 /* An array of architecture specific rules */
234 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
235 
236 static LIST_HEAD(ima_default_rules);
237 static LIST_HEAD(ima_policy_rules);
238 static LIST_HEAD(ima_temp_rules);
239 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
240 
241 static int ima_policy __initdata;
242 
243 static int __init default_measure_policy_setup(char *str)
244 {
245 	if (ima_policy)
246 		return 1;
247 
248 	ima_policy = ORIGINAL_TCB;
249 	return 1;
250 }
251 __setup("ima_tcb", default_measure_policy_setup);
252 
253 static bool ima_use_appraise_tcb __initdata;
254 static bool ima_use_secure_boot __initdata;
255 static bool ima_use_critical_data __initdata;
256 static bool ima_fail_unverifiable_sigs __ro_after_init;
257 static int __init policy_setup(char *str)
258 {
259 	char *p;
260 
261 	while ((p = strsep(&str, " |\n")) != NULL) {
262 		if (*p == ' ')
263 			continue;
264 		if ((strcmp(p, "tcb") == 0) && !ima_policy)
265 			ima_policy = DEFAULT_TCB;
266 		else if (strcmp(p, "appraise_tcb") == 0)
267 			ima_use_appraise_tcb = true;
268 		else if (strcmp(p, "secure_boot") == 0)
269 			ima_use_secure_boot = true;
270 		else if (strcmp(p, "critical_data") == 0)
271 			ima_use_critical_data = true;
272 		else if (strcmp(p, "fail_securely") == 0)
273 			ima_fail_unverifiable_sigs = true;
274 		else
275 			pr_err("policy \"%s\" not found", p);
276 	}
277 
278 	return 1;
279 }
280 __setup("ima_policy=", policy_setup);
281 
282 static int __init default_appraise_policy_setup(char *str)
283 {
284 	ima_use_appraise_tcb = true;
285 	return 1;
286 }
287 __setup("ima_appraise_tcb", default_appraise_policy_setup);
288 
289 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
290 {
291 	struct ima_rule_opt_list *opt_list;
292 	size_t count = 0;
293 	char *src_copy;
294 	char *cur, *next;
295 	size_t i;
296 
297 	src_copy = match_strdup(src);
298 	if (!src_copy)
299 		return ERR_PTR(-ENOMEM);
300 
301 	next = src_copy;
302 	while ((cur = strsep(&next, "|"))) {
303 		/* Don't accept an empty list item */
304 		if (!(*cur)) {
305 			kfree(src_copy);
306 			return ERR_PTR(-EINVAL);
307 		}
308 		count++;
309 	}
310 
311 	/* Don't accept an empty list */
312 	if (!count) {
313 		kfree(src_copy);
314 		return ERR_PTR(-EINVAL);
315 	}
316 
317 	opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
318 	if (!opt_list) {
319 		kfree(src_copy);
320 		return ERR_PTR(-ENOMEM);
321 	}
322 
323 	/*
324 	 * strsep() has already replaced all instances of '|' with '\0',
325 	 * leaving a byte sequence of NUL-terminated strings. Reference each
326 	 * string with the array of items.
327 	 *
328 	 * IMPORTANT: Ownership of the allocated buffer is transferred from
329 	 * src_copy to the first element in the items array. To free the
330 	 * buffer, kfree() must only be called on the first element of the
331 	 * array.
332 	 */
333 	for (i = 0, cur = src_copy; i < count; i++) {
334 		opt_list->items[i] = cur;
335 		cur = strchr(cur, '\0') + 1;
336 	}
337 	opt_list->count = count;
338 
339 	return opt_list;
340 }
341 
342 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
343 {
344 	if (!opt_list)
345 		return;
346 
347 	if (opt_list->count) {
348 		kfree(opt_list->items[0]);
349 		opt_list->count = 0;
350 	}
351 
352 	kfree(opt_list);
353 }
354 
355 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
356 {
357 	int i;
358 
359 	for (i = 0; i < MAX_LSM_RULES; i++) {
360 		ima_filter_rule_free(entry->lsm[i].rule);
361 		kfree(entry->lsm[i].args_p);
362 	}
363 }
364 
365 static void ima_free_rule(struct ima_rule_entry *entry)
366 {
367 	if (!entry)
368 		return;
369 
370 	/*
371 	 * entry->template->fields may be allocated in ima_parse_rule() but that
372 	 * reference is owned by the corresponding ima_template_desc element in
373 	 * the defined_templates list and cannot be freed here
374 	 */
375 	kfree(entry->fsname);
376 	ima_free_rule_opt_list(entry->keyrings);
377 	ima_lsm_free_rule(entry);
378 	kfree(entry);
379 }
380 
381 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
382 {
383 	struct ima_rule_entry *nentry;
384 	int i;
385 
386 	/*
387 	 * Immutable elements are copied over as pointers and data; only
388 	 * lsm rules can change
389 	 */
390 	nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
391 	if (!nentry)
392 		return NULL;
393 
394 	memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
395 
396 	for (i = 0; i < MAX_LSM_RULES; i++) {
397 		if (!entry->lsm[i].args_p)
398 			continue;
399 
400 		nentry->lsm[i].type = entry->lsm[i].type;
401 		nentry->lsm[i].args_p = entry->lsm[i].args_p;
402 		/*
403 		 * Remove the reference from entry so that the associated
404 		 * memory will not be freed during a later call to
405 		 * ima_lsm_free_rule(entry).
406 		 */
407 		entry->lsm[i].args_p = NULL;
408 
409 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
410 				     nentry->lsm[i].args_p,
411 				     &nentry->lsm[i].rule);
412 		if (!nentry->lsm[i].rule)
413 			pr_warn("rule for LSM \'%s\' is undefined\n",
414 				nentry->lsm[i].args_p);
415 	}
416 	return nentry;
417 }
418 
419 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
420 {
421 	struct ima_rule_entry *nentry;
422 
423 	nentry = ima_lsm_copy_rule(entry);
424 	if (!nentry)
425 		return -ENOMEM;
426 
427 	list_replace_rcu(&entry->list, &nentry->list);
428 	synchronize_rcu();
429 	/*
430 	 * ima_lsm_copy_rule() shallow copied all references, except for the
431 	 * LSM references, from entry to nentry so we only want to free the LSM
432 	 * references and the entry itself. All other memory refrences will now
433 	 * be owned by nentry.
434 	 */
435 	ima_lsm_free_rule(entry);
436 	kfree(entry);
437 
438 	return 0;
439 }
440 
441 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
442 {
443 	int i;
444 
445 	for (i = 0; i < MAX_LSM_RULES; i++)
446 		if (entry->lsm[i].args_p)
447 			return true;
448 
449 	return false;
450 }
451 
452 /*
453  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
454  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
455  * the reloaded LSM policy.
456  */
457 static void ima_lsm_update_rules(void)
458 {
459 	struct ima_rule_entry *entry, *e;
460 	int result;
461 
462 	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
463 		if (!ima_rule_contains_lsm_cond(entry))
464 			continue;
465 
466 		result = ima_lsm_update_rule(entry);
467 		if (result) {
468 			pr_err("lsm rule update error %d\n", result);
469 			return;
470 		}
471 	}
472 }
473 
474 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
475 			  void *lsm_data)
476 {
477 	if (event != LSM_POLICY_CHANGE)
478 		return NOTIFY_DONE;
479 
480 	ima_lsm_update_rules();
481 	return NOTIFY_OK;
482 }
483 
484 /**
485  * ima_match_rule_data - determine whether func_data matches the policy rule
486  * @rule: a pointer to a rule
487  * @func_data: data to match against the measure rule data
488  * @cred: a pointer to a credentials structure for user validation
489  *
490  * Returns true if func_data matches one in the rule, false otherwise.
491  */
492 static bool ima_match_rule_data(struct ima_rule_entry *rule,
493 				const char *func_data,
494 				const struct cred *cred)
495 {
496 	const struct ima_rule_opt_list *opt_list = NULL;
497 	bool matched = false;
498 	size_t i;
499 
500 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
501 		return false;
502 
503 	switch (rule->func) {
504 	case KEY_CHECK:
505 		if (!rule->keyrings)
506 			return true;
507 
508 		opt_list = rule->keyrings;
509 		break;
510 	case CRITICAL_DATA:
511 		if (!rule->label)
512 			return true;
513 
514 		opt_list = rule->label;
515 		break;
516 	default:
517 		return false;
518 	}
519 
520 	if (!func_data)
521 		return false;
522 
523 	for (i = 0; i < opt_list->count; i++) {
524 		if (!strcmp(opt_list->items[i], func_data)) {
525 			matched = true;
526 			break;
527 		}
528 	}
529 
530 	return matched;
531 }
532 
533 /**
534  * ima_match_rules - determine whether an inode matches the policy rule.
535  * @rule: a pointer to a rule
536  * @mnt_userns:	user namespace of the mount the inode was found from
537  * @inode: a pointer to an inode
538  * @cred: a pointer to a credentials structure for user validation
539  * @secid: the secid of the task to be validated
540  * @func: LIM hook identifier
541  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
542  * @func_data: func specific data, may be NULL
543  *
544  * Returns true on rule match, false on failure.
545  */
546 static bool ima_match_rules(struct ima_rule_entry *rule,
547 			    struct user_namespace *mnt_userns,
548 			    struct inode *inode, const struct cred *cred,
549 			    u32 secid, enum ima_hooks func, int mask,
550 			    const char *func_data)
551 {
552 	int i;
553 
554 	if ((rule->flags & IMA_FUNC) &&
555 	    (rule->func != func && func != POST_SETATTR))
556 		return false;
557 
558 	switch (func) {
559 	case KEY_CHECK:
560 	case CRITICAL_DATA:
561 		return ((rule->func == func) &&
562 			ima_match_rule_data(rule, func_data, cred));
563 	default:
564 		break;
565 	}
566 
567 	if ((rule->flags & IMA_MASK) &&
568 	    (rule->mask != mask && func != POST_SETATTR))
569 		return false;
570 	if ((rule->flags & IMA_INMASK) &&
571 	    (!(rule->mask & mask) && func != POST_SETATTR))
572 		return false;
573 	if ((rule->flags & IMA_FSMAGIC)
574 	    && rule->fsmagic != inode->i_sb->s_magic)
575 		return false;
576 	if ((rule->flags & IMA_FSNAME)
577 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
578 		return false;
579 	if ((rule->flags & IMA_FSUUID) &&
580 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
581 		return false;
582 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
583 		return false;
584 	if (rule->flags & IMA_EUID) {
585 		if (has_capability_noaudit(current, CAP_SETUID)) {
586 			if (!rule->uid_op(cred->euid, rule->uid)
587 			    && !rule->uid_op(cred->suid, rule->uid)
588 			    && !rule->uid_op(cred->uid, rule->uid))
589 				return false;
590 		} else if (!rule->uid_op(cred->euid, rule->uid))
591 			return false;
592 	}
593 	if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
594 		return false;
595 	if (rule->flags & IMA_EGID) {
596 		if (has_capability_noaudit(current, CAP_SETGID)) {
597 			if (!rule->gid_op(cred->egid, rule->gid)
598 			    && !rule->gid_op(cred->sgid, rule->gid)
599 			    && !rule->gid_op(cred->gid, rule->gid))
600 				return false;
601 		} else if (!rule->gid_op(cred->egid, rule->gid))
602 			return false;
603 	}
604 	if ((rule->flags & IMA_FOWNER) &&
605 	    !rule->fowner_op(i_uid_into_mnt(mnt_userns, inode), rule->fowner))
606 		return false;
607 	if ((rule->flags & IMA_FGROUP) &&
608 	    !rule->fgroup_op(i_gid_into_mnt(mnt_userns, inode), rule->fgroup))
609 		return false;
610 	for (i = 0; i < MAX_LSM_RULES; i++) {
611 		int rc = 0;
612 		u32 osid;
613 
614 		if (!rule->lsm[i].rule) {
615 			if (!rule->lsm[i].args_p)
616 				continue;
617 			else
618 				return false;
619 		}
620 		switch (i) {
621 		case LSM_OBJ_USER:
622 		case LSM_OBJ_ROLE:
623 		case LSM_OBJ_TYPE:
624 			security_inode_getsecid(inode, &osid);
625 			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
626 						   Audit_equal,
627 						   rule->lsm[i].rule);
628 			break;
629 		case LSM_SUBJ_USER:
630 		case LSM_SUBJ_ROLE:
631 		case LSM_SUBJ_TYPE:
632 			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
633 						   Audit_equal,
634 						   rule->lsm[i].rule);
635 			break;
636 		default:
637 			break;
638 		}
639 		if (!rc)
640 			return false;
641 	}
642 	return true;
643 }
644 
645 /*
646  * In addition to knowing that we need to appraise the file in general,
647  * we need to differentiate between calling hooks, for hook specific rules.
648  */
649 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
650 {
651 	if (!(rule->flags & IMA_FUNC))
652 		return IMA_FILE_APPRAISE;
653 
654 	switch (func) {
655 	case MMAP_CHECK:
656 		return IMA_MMAP_APPRAISE;
657 	case BPRM_CHECK:
658 		return IMA_BPRM_APPRAISE;
659 	case CREDS_CHECK:
660 		return IMA_CREDS_APPRAISE;
661 	case FILE_CHECK:
662 	case POST_SETATTR:
663 		return IMA_FILE_APPRAISE;
664 	case MODULE_CHECK ... MAX_CHECK - 1:
665 	default:
666 		return IMA_READ_APPRAISE;
667 	}
668 }
669 
670 /**
671  * ima_match_policy - decision based on LSM and other conditions
672  * @mnt_userns:	user namespace of the mount the inode was found from
673  * @inode: pointer to an inode for which the policy decision is being made
674  * @cred: pointer to a credentials structure for which the policy decision is
675  *        being made
676  * @secid: LSM secid of the task to be validated
677  * @func: IMA hook identifier
678  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
679  * @pcr: set the pcr to extend
680  * @template_desc: the template that should be used for this rule
681  * @func_data: func specific data, may be NULL
682  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
683  *
684  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
685  * conditions.
686  *
687  * Since the IMA policy may be updated multiple times we need to lock the
688  * list when walking it.  Reads are many orders of magnitude more numerous
689  * than writes so ima_match_policy() is classical RCU candidate.
690  */
691 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
692 		     const struct cred *cred, u32 secid, enum ima_hooks func,
693 		     int mask, int flags, int *pcr,
694 		     struct ima_template_desc **template_desc,
695 		     const char *func_data, unsigned int *allowed_algos)
696 {
697 	struct ima_rule_entry *entry;
698 	int action = 0, actmask = flags | (flags << 1);
699 	struct list_head *ima_rules_tmp;
700 
701 	if (template_desc && !*template_desc)
702 		*template_desc = ima_template_desc_current();
703 
704 	rcu_read_lock();
705 	ima_rules_tmp = rcu_dereference(ima_rules);
706 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
707 
708 		if (!(entry->action & actmask))
709 			continue;
710 
711 		if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
712 				     func, mask, func_data))
713 			continue;
714 
715 		action |= entry->flags & IMA_ACTION_FLAGS;
716 
717 		action |= entry->action & IMA_DO_MASK;
718 		if (entry->action & IMA_APPRAISE) {
719 			action |= get_subaction(entry, func);
720 			action &= ~IMA_HASH;
721 			if (ima_fail_unverifiable_sigs)
722 				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
723 
724 			if (allowed_algos &&
725 			    entry->flags & IMA_VALIDATE_ALGOS)
726 				*allowed_algos = entry->allowed_algos;
727 		}
728 
729 		if (entry->action & IMA_DO_MASK)
730 			actmask &= ~(entry->action | entry->action << 1);
731 		else
732 			actmask &= ~(entry->action | entry->action >> 1);
733 
734 		if ((pcr) && (entry->flags & IMA_PCR))
735 			*pcr = entry->pcr;
736 
737 		if (template_desc && entry->template)
738 			*template_desc = entry->template;
739 
740 		if (!actmask)
741 			break;
742 	}
743 	rcu_read_unlock();
744 
745 	return action;
746 }
747 
748 /**
749  * ima_update_policy_flags() - Update global IMA variables
750  *
751  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
752  * based on the currently loaded policy.
753  *
754  * With ima_policy_flag, the decision to short circuit out of a function
755  * or not call the function in the first place can be made earlier.
756  *
757  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
758  * set of hash algorithms accepted when updating the security.ima xattr of
759  * a file.
760  *
761  * Context: called after a policy update and at system initialization.
762  */
763 void ima_update_policy_flags(void)
764 {
765 	struct ima_rule_entry *entry;
766 	int new_policy_flag = 0;
767 	struct list_head *ima_rules_tmp;
768 
769 	rcu_read_lock();
770 	ima_rules_tmp = rcu_dereference(ima_rules);
771 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
772 		/*
773 		 * SETXATTR_CHECK rules do not implement a full policy check
774 		 * because rule checking would probably have an important
775 		 * performance impact on setxattr(). As a consequence, only one
776 		 * SETXATTR_CHECK can be active at a given time.
777 		 * Because we want to preserve that property, we set out to use
778 		 * atomic_cmpxchg. Either:
779 		 * - the atomic was non-zero: a setxattr hash policy is
780 		 *   already enforced, we do nothing
781 		 * - the atomic was zero: no setxattr policy was set, enable
782 		 *   the setxattr hash policy
783 		 */
784 		if (entry->func == SETXATTR_CHECK) {
785 			atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
786 				       0, entry->allowed_algos);
787 			/* SETXATTR_CHECK doesn't impact ima_policy_flag */
788 			continue;
789 		}
790 
791 		if (entry->action & IMA_DO_MASK)
792 			new_policy_flag |= entry->action;
793 	}
794 	rcu_read_unlock();
795 
796 	ima_appraise |= (build_ima_appraise | temp_ima_appraise);
797 	if (!ima_appraise)
798 		new_policy_flag &= ~IMA_APPRAISE;
799 
800 	ima_policy_flag = new_policy_flag;
801 }
802 
803 static int ima_appraise_flag(enum ima_hooks func)
804 {
805 	if (func == MODULE_CHECK)
806 		return IMA_APPRAISE_MODULES;
807 	else if (func == FIRMWARE_CHECK)
808 		return IMA_APPRAISE_FIRMWARE;
809 	else if (func == POLICY_CHECK)
810 		return IMA_APPRAISE_POLICY;
811 	else if (func == KEXEC_KERNEL_CHECK)
812 		return IMA_APPRAISE_KEXEC;
813 	return 0;
814 }
815 
816 static void add_rules(struct ima_rule_entry *entries, int count,
817 		      enum policy_rule_list policy_rule)
818 {
819 	int i = 0;
820 
821 	for (i = 0; i < count; i++) {
822 		struct ima_rule_entry *entry;
823 
824 		if (policy_rule & IMA_DEFAULT_POLICY)
825 			list_add_tail(&entries[i].list, &ima_default_rules);
826 
827 		if (policy_rule & IMA_CUSTOM_POLICY) {
828 			entry = kmemdup(&entries[i], sizeof(*entry),
829 					GFP_KERNEL);
830 			if (!entry)
831 				continue;
832 
833 			list_add_tail(&entry->list, &ima_policy_rules);
834 		}
835 		if (entries[i].action == APPRAISE) {
836 			if (entries != build_appraise_rules)
837 				temp_ima_appraise |=
838 					ima_appraise_flag(entries[i].func);
839 			else
840 				build_ima_appraise |=
841 					ima_appraise_flag(entries[i].func);
842 		}
843 	}
844 }
845 
846 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
847 
848 static int __init ima_init_arch_policy(void)
849 {
850 	const char * const *arch_rules;
851 	const char * const *rules;
852 	int arch_entries = 0;
853 	int i = 0;
854 
855 	arch_rules = arch_get_ima_policy();
856 	if (!arch_rules)
857 		return arch_entries;
858 
859 	/* Get number of rules */
860 	for (rules = arch_rules; *rules != NULL; rules++)
861 		arch_entries++;
862 
863 	arch_policy_entry = kcalloc(arch_entries + 1,
864 				    sizeof(*arch_policy_entry), GFP_KERNEL);
865 	if (!arch_policy_entry)
866 		return 0;
867 
868 	/* Convert each policy string rules to struct ima_rule_entry format */
869 	for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
870 		char rule[255];
871 		int result;
872 
873 		result = strscpy(rule, *rules, sizeof(rule));
874 
875 		INIT_LIST_HEAD(&arch_policy_entry[i].list);
876 		result = ima_parse_rule(rule, &arch_policy_entry[i]);
877 		if (result) {
878 			pr_warn("Skipping unknown architecture policy rule: %s\n",
879 				rule);
880 			memset(&arch_policy_entry[i], 0,
881 			       sizeof(*arch_policy_entry));
882 			continue;
883 		}
884 		i++;
885 	}
886 	return i;
887 }
888 
889 /**
890  * ima_init_policy - initialize the default measure rules.
891  *
892  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
893  */
894 void __init ima_init_policy(void)
895 {
896 	int build_appraise_entries, arch_entries;
897 
898 	/* if !ima_policy, we load NO default rules */
899 	if (ima_policy)
900 		add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
901 			  IMA_DEFAULT_POLICY);
902 
903 	switch (ima_policy) {
904 	case ORIGINAL_TCB:
905 		add_rules(original_measurement_rules,
906 			  ARRAY_SIZE(original_measurement_rules),
907 			  IMA_DEFAULT_POLICY);
908 		break;
909 	case DEFAULT_TCB:
910 		add_rules(default_measurement_rules,
911 			  ARRAY_SIZE(default_measurement_rules),
912 			  IMA_DEFAULT_POLICY);
913 		break;
914 	default:
915 		break;
916 	}
917 
918 	/*
919 	 * Based on runtime secure boot flags, insert arch specific measurement
920 	 * and appraise rules requiring file signatures for both the initial
921 	 * and custom policies, prior to other appraise rules.
922 	 * (Highest priority)
923 	 */
924 	arch_entries = ima_init_arch_policy();
925 	if (!arch_entries)
926 		pr_info("No architecture policies found\n");
927 	else
928 		add_rules(arch_policy_entry, arch_entries,
929 			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
930 
931 	/*
932 	 * Insert the builtin "secure_boot" policy rules requiring file
933 	 * signatures, prior to other appraise rules.
934 	 */
935 	if (ima_use_secure_boot)
936 		add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
937 			  IMA_DEFAULT_POLICY);
938 
939 	/*
940 	 * Insert the build time appraise rules requiring file signatures
941 	 * for both the initial and custom policies, prior to other appraise
942 	 * rules. As the secure boot rules includes all of the build time
943 	 * rules, include either one or the other set of rules, but not both.
944 	 */
945 	build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
946 	if (build_appraise_entries) {
947 		if (ima_use_secure_boot)
948 			add_rules(build_appraise_rules, build_appraise_entries,
949 				  IMA_CUSTOM_POLICY);
950 		else
951 			add_rules(build_appraise_rules, build_appraise_entries,
952 				  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
953 	}
954 
955 	if (ima_use_appraise_tcb)
956 		add_rules(default_appraise_rules,
957 			  ARRAY_SIZE(default_appraise_rules),
958 			  IMA_DEFAULT_POLICY);
959 
960 	if (ima_use_critical_data)
961 		add_rules(critical_data_rules,
962 			  ARRAY_SIZE(critical_data_rules),
963 			  IMA_DEFAULT_POLICY);
964 
965 	atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
966 
967 	ima_update_policy_flags();
968 }
969 
970 /* Make sure we have a valid policy, at least containing some rules. */
971 int ima_check_policy(void)
972 {
973 	if (list_empty(&ima_temp_rules))
974 		return -EINVAL;
975 	return 0;
976 }
977 
978 /**
979  * ima_update_policy - update default_rules with new measure rules
980  *
981  * Called on file .release to update the default rules with a complete new
982  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
983  * they make a queue.  The policy may be updated multiple times and this is the
984  * RCU updater.
985  *
986  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
987  * we switch from the default policy to user defined.
988  */
989 void ima_update_policy(void)
990 {
991 	struct list_head *policy = &ima_policy_rules;
992 
993 	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
994 
995 	if (ima_rules != (struct list_head __rcu *)policy) {
996 		ima_policy_flag = 0;
997 
998 		rcu_assign_pointer(ima_rules, policy);
999 		/*
1000 		 * IMA architecture specific policy rules are specified
1001 		 * as strings and converted to an array of ima_entry_rules
1002 		 * on boot.  After loading a custom policy, free the
1003 		 * architecture specific rules stored as an array.
1004 		 */
1005 		kfree(arch_policy_entry);
1006 	}
1007 	ima_update_policy_flags();
1008 
1009 	/* Custom IMA policy has been loaded */
1010 	ima_process_queued_keys();
1011 }
1012 
1013 /* Keep the enumeration in sync with the policy_tokens! */
1014 enum policy_opt {
1015 	Opt_measure, Opt_dont_measure,
1016 	Opt_appraise, Opt_dont_appraise,
1017 	Opt_audit, Opt_hash, Opt_dont_hash,
1018 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
1019 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
1020 	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1021 	Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1022 	Opt_fowner_eq, Opt_fgroup_eq,
1023 	Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1024 	Opt_fowner_gt, Opt_fgroup_gt,
1025 	Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1026 	Opt_fowner_lt, Opt_fgroup_lt,
1027 	Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1028 	Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1029 	Opt_label, Opt_err
1030 };
1031 
1032 static const match_table_t policy_tokens = {
1033 	{Opt_measure, "measure"},
1034 	{Opt_dont_measure, "dont_measure"},
1035 	{Opt_appraise, "appraise"},
1036 	{Opt_dont_appraise, "dont_appraise"},
1037 	{Opt_audit, "audit"},
1038 	{Opt_hash, "hash"},
1039 	{Opt_dont_hash, "dont_hash"},
1040 	{Opt_obj_user, "obj_user=%s"},
1041 	{Opt_obj_role, "obj_role=%s"},
1042 	{Opt_obj_type, "obj_type=%s"},
1043 	{Opt_subj_user, "subj_user=%s"},
1044 	{Opt_subj_role, "subj_role=%s"},
1045 	{Opt_subj_type, "subj_type=%s"},
1046 	{Opt_func, "func=%s"},
1047 	{Opt_mask, "mask=%s"},
1048 	{Opt_fsmagic, "fsmagic=%s"},
1049 	{Opt_fsname, "fsname=%s"},
1050 	{Opt_fsuuid, "fsuuid=%s"},
1051 	{Opt_uid_eq, "uid=%s"},
1052 	{Opt_euid_eq, "euid=%s"},
1053 	{Opt_gid_eq, "gid=%s"},
1054 	{Opt_egid_eq, "egid=%s"},
1055 	{Opt_fowner_eq, "fowner=%s"},
1056 	{Opt_fgroup_eq, "fgroup=%s"},
1057 	{Opt_uid_gt, "uid>%s"},
1058 	{Opt_euid_gt, "euid>%s"},
1059 	{Opt_gid_gt, "gid>%s"},
1060 	{Opt_egid_gt, "egid>%s"},
1061 	{Opt_fowner_gt, "fowner>%s"},
1062 	{Opt_fgroup_gt, "fgroup>%s"},
1063 	{Opt_uid_lt, "uid<%s"},
1064 	{Opt_euid_lt, "euid<%s"},
1065 	{Opt_gid_lt, "gid<%s"},
1066 	{Opt_egid_lt, "egid<%s"},
1067 	{Opt_fowner_lt, "fowner<%s"},
1068 	{Opt_fgroup_lt, "fgroup<%s"},
1069 	{Opt_appraise_type, "appraise_type=%s"},
1070 	{Opt_appraise_flag, "appraise_flag=%s"},
1071 	{Opt_appraise_algos, "appraise_algos=%s"},
1072 	{Opt_permit_directio, "permit_directio"},
1073 	{Opt_pcr, "pcr=%s"},
1074 	{Opt_template, "template=%s"},
1075 	{Opt_keyrings, "keyrings=%s"},
1076 	{Opt_label, "label=%s"},
1077 	{Opt_err, NULL}
1078 };
1079 
1080 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1081 			     substring_t *args, int lsm_rule, int audit_type)
1082 {
1083 	int result;
1084 
1085 	if (entry->lsm[lsm_rule].rule)
1086 		return -EINVAL;
1087 
1088 	entry->lsm[lsm_rule].args_p = match_strdup(args);
1089 	if (!entry->lsm[lsm_rule].args_p)
1090 		return -ENOMEM;
1091 
1092 	entry->lsm[lsm_rule].type = audit_type;
1093 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1094 				      entry->lsm[lsm_rule].args_p,
1095 				      &entry->lsm[lsm_rule].rule);
1096 	if (!entry->lsm[lsm_rule].rule) {
1097 		pr_warn("rule for LSM \'%s\' is undefined\n",
1098 			entry->lsm[lsm_rule].args_p);
1099 
1100 		if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1101 			kfree(entry->lsm[lsm_rule].args_p);
1102 			entry->lsm[lsm_rule].args_p = NULL;
1103 			result = -EINVAL;
1104 		} else
1105 			result = 0;
1106 	}
1107 
1108 	return result;
1109 }
1110 
1111 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1112 			      enum policy_opt rule_operator)
1113 {
1114 	if (!ab)
1115 		return;
1116 
1117 	switch (rule_operator) {
1118 	case Opt_uid_gt:
1119 	case Opt_euid_gt:
1120 	case Opt_gid_gt:
1121 	case Opt_egid_gt:
1122 	case Opt_fowner_gt:
1123 	case Opt_fgroup_gt:
1124 		audit_log_format(ab, "%s>", key);
1125 		break;
1126 	case Opt_uid_lt:
1127 	case Opt_euid_lt:
1128 	case Opt_gid_lt:
1129 	case Opt_egid_lt:
1130 	case Opt_fowner_lt:
1131 	case Opt_fgroup_lt:
1132 		audit_log_format(ab, "%s<", key);
1133 		break;
1134 	default:
1135 		audit_log_format(ab, "%s=", key);
1136 	}
1137 	audit_log_format(ab, "%s ", value);
1138 }
1139 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1140 {
1141 	ima_log_string_op(ab, key, value, Opt_err);
1142 }
1143 
1144 /*
1145  * Validating the appended signature included in the measurement list requires
1146  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1147  * field). Therefore, notify the user if they have the 'modsig' field but not
1148  * the 'd-modsig' field in the template.
1149  */
1150 static void check_template_modsig(const struct ima_template_desc *template)
1151 {
1152 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1153 	bool has_modsig, has_dmodsig;
1154 	static bool checked;
1155 	int i;
1156 
1157 	/* We only need to notify the user once. */
1158 	if (checked)
1159 		return;
1160 
1161 	has_modsig = has_dmodsig = false;
1162 	for (i = 0; i < template->num_fields; i++) {
1163 		if (!strcmp(template->fields[i]->field_id, "modsig"))
1164 			has_modsig = true;
1165 		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1166 			has_dmodsig = true;
1167 	}
1168 
1169 	if (has_modsig && !has_dmodsig)
1170 		pr_notice(MSG);
1171 
1172 	checked = true;
1173 #undef MSG
1174 }
1175 
1176 static bool ima_validate_rule(struct ima_rule_entry *entry)
1177 {
1178 	/* Ensure that the action is set and is compatible with the flags */
1179 	if (entry->action == UNKNOWN)
1180 		return false;
1181 
1182 	if (entry->action != MEASURE && entry->flags & IMA_PCR)
1183 		return false;
1184 
1185 	if (entry->action != APPRAISE &&
1186 	    entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1187 			    IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1188 		return false;
1189 
1190 	/*
1191 	 * The IMA_FUNC bit must be set if and only if there's a valid hook
1192 	 * function specified, and vice versa. Enforcing this property allows
1193 	 * for the NONE case below to validate a rule without an explicit hook
1194 	 * function.
1195 	 */
1196 	if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1197 	    (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1198 		return false;
1199 
1200 	/*
1201 	 * Ensure that the hook function is compatible with the other
1202 	 * components of the rule
1203 	 */
1204 	switch (entry->func) {
1205 	case NONE:
1206 	case FILE_CHECK:
1207 	case MMAP_CHECK:
1208 	case BPRM_CHECK:
1209 	case CREDS_CHECK:
1210 	case POST_SETATTR:
1211 	case FIRMWARE_CHECK:
1212 	case POLICY_CHECK:
1213 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1214 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1215 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1216 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1217 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1218 				     IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS))
1219 			return false;
1220 
1221 		break;
1222 	case MODULE_CHECK:
1223 	case KEXEC_KERNEL_CHECK:
1224 	case KEXEC_INITRAMFS_CHECK:
1225 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1226 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1227 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1228 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1229 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1230 				     IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1231 				     IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1232 			return false;
1233 
1234 		break;
1235 	case KEXEC_CMDLINE:
1236 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1237 			return false;
1238 
1239 		if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1240 				     IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1241 				     IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1242 				     IMA_FGROUP))
1243 			return false;
1244 
1245 		break;
1246 	case KEY_CHECK:
1247 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1248 			return false;
1249 
1250 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1251 				     IMA_KEYRINGS))
1252 			return false;
1253 
1254 		if (ima_rule_contains_lsm_cond(entry))
1255 			return false;
1256 
1257 		break;
1258 	case CRITICAL_DATA:
1259 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1260 			return false;
1261 
1262 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1263 				     IMA_LABEL))
1264 			return false;
1265 
1266 		if (ima_rule_contains_lsm_cond(entry))
1267 			return false;
1268 
1269 		break;
1270 	case SETXATTR_CHECK:
1271 		/* any action other than APPRAISE is unsupported */
1272 		if (entry->action != APPRAISE)
1273 			return false;
1274 
1275 		/* SETXATTR_CHECK requires an appraise_algos parameter */
1276 		if (!(entry->flags & IMA_VALIDATE_ALGOS))
1277 			return false;
1278 
1279 		/*
1280 		 * full policies are not supported, they would have too
1281 		 * much of a performance impact
1282 		 */
1283 		if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1284 			return false;
1285 
1286 		break;
1287 	default:
1288 		return false;
1289 	}
1290 
1291 	/* Ensure that combinations of flags are compatible with each other */
1292 	if (entry->flags & IMA_CHECK_BLACKLIST &&
1293 	    !(entry->flags & IMA_MODSIG_ALLOWED))
1294 		return false;
1295 
1296 	return true;
1297 }
1298 
1299 static unsigned int ima_parse_appraise_algos(char *arg)
1300 {
1301 	unsigned int res = 0;
1302 	int idx;
1303 	char *token;
1304 
1305 	while ((token = strsep(&arg, ",")) != NULL) {
1306 		idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1307 
1308 		if (idx < 0) {
1309 			pr_err("unknown hash algorithm \"%s\"",
1310 			       token);
1311 			return 0;
1312 		}
1313 
1314 		if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1315 			pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1316 			       token);
1317 			return 0;
1318 		}
1319 
1320 		/* Add the hash algorithm to the 'allowed' bitfield */
1321 		res |= (1U << idx);
1322 	}
1323 
1324 	return res;
1325 }
1326 
1327 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1328 {
1329 	struct audit_buffer *ab;
1330 	char *from;
1331 	char *p;
1332 	bool eid_token; /* either euid or egid */
1333 	struct ima_template_desc *template_desc;
1334 	int result = 0;
1335 
1336 	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1337 				       AUDIT_INTEGRITY_POLICY_RULE);
1338 
1339 	entry->uid = INVALID_UID;
1340 	entry->gid = INVALID_GID;
1341 	entry->fowner = INVALID_UID;
1342 	entry->fgroup = INVALID_GID;
1343 	entry->uid_op = &uid_eq;
1344 	entry->gid_op = &gid_eq;
1345 	entry->fowner_op = &uid_eq;
1346 	entry->fgroup_op = &gid_eq;
1347 	entry->action = UNKNOWN;
1348 	while ((p = strsep(&rule, " \t")) != NULL) {
1349 		substring_t args[MAX_OPT_ARGS];
1350 		int token;
1351 		unsigned long lnum;
1352 
1353 		if (result < 0)
1354 			break;
1355 		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1356 			continue;
1357 		token = match_token(p, policy_tokens, args);
1358 		switch (token) {
1359 		case Opt_measure:
1360 			ima_log_string(ab, "action", "measure");
1361 
1362 			if (entry->action != UNKNOWN)
1363 				result = -EINVAL;
1364 
1365 			entry->action = MEASURE;
1366 			break;
1367 		case Opt_dont_measure:
1368 			ima_log_string(ab, "action", "dont_measure");
1369 
1370 			if (entry->action != UNKNOWN)
1371 				result = -EINVAL;
1372 
1373 			entry->action = DONT_MEASURE;
1374 			break;
1375 		case Opt_appraise:
1376 			ima_log_string(ab, "action", "appraise");
1377 
1378 			if (entry->action != UNKNOWN)
1379 				result = -EINVAL;
1380 
1381 			entry->action = APPRAISE;
1382 			break;
1383 		case Opt_dont_appraise:
1384 			ima_log_string(ab, "action", "dont_appraise");
1385 
1386 			if (entry->action != UNKNOWN)
1387 				result = -EINVAL;
1388 
1389 			entry->action = DONT_APPRAISE;
1390 			break;
1391 		case Opt_audit:
1392 			ima_log_string(ab, "action", "audit");
1393 
1394 			if (entry->action != UNKNOWN)
1395 				result = -EINVAL;
1396 
1397 			entry->action = AUDIT;
1398 			break;
1399 		case Opt_hash:
1400 			ima_log_string(ab, "action", "hash");
1401 
1402 			if (entry->action != UNKNOWN)
1403 				result = -EINVAL;
1404 
1405 			entry->action = HASH;
1406 			break;
1407 		case Opt_dont_hash:
1408 			ima_log_string(ab, "action", "dont_hash");
1409 
1410 			if (entry->action != UNKNOWN)
1411 				result = -EINVAL;
1412 
1413 			entry->action = DONT_HASH;
1414 			break;
1415 		case Opt_func:
1416 			ima_log_string(ab, "func", args[0].from);
1417 
1418 			if (entry->func)
1419 				result = -EINVAL;
1420 
1421 			if (strcmp(args[0].from, "FILE_CHECK") == 0)
1422 				entry->func = FILE_CHECK;
1423 			/* PATH_CHECK is for backwards compat */
1424 			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1425 				entry->func = FILE_CHECK;
1426 			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1427 				entry->func = MODULE_CHECK;
1428 			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1429 				entry->func = FIRMWARE_CHECK;
1430 			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1431 				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
1432 				entry->func = MMAP_CHECK;
1433 			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1434 				entry->func = BPRM_CHECK;
1435 			else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1436 				entry->func = CREDS_CHECK;
1437 			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1438 				 0)
1439 				entry->func = KEXEC_KERNEL_CHECK;
1440 			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1441 				 == 0)
1442 				entry->func = KEXEC_INITRAMFS_CHECK;
1443 			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1444 				entry->func = POLICY_CHECK;
1445 			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1446 				entry->func = KEXEC_CMDLINE;
1447 			else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1448 				 strcmp(args[0].from, "KEY_CHECK") == 0)
1449 				entry->func = KEY_CHECK;
1450 			else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1451 				entry->func = CRITICAL_DATA;
1452 			else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1453 				entry->func = SETXATTR_CHECK;
1454 			else
1455 				result = -EINVAL;
1456 			if (!result)
1457 				entry->flags |= IMA_FUNC;
1458 			break;
1459 		case Opt_mask:
1460 			ima_log_string(ab, "mask", args[0].from);
1461 
1462 			if (entry->mask)
1463 				result = -EINVAL;
1464 
1465 			from = args[0].from;
1466 			if (*from == '^')
1467 				from++;
1468 
1469 			if ((strcmp(from, "MAY_EXEC")) == 0)
1470 				entry->mask = MAY_EXEC;
1471 			else if (strcmp(from, "MAY_WRITE") == 0)
1472 				entry->mask = MAY_WRITE;
1473 			else if (strcmp(from, "MAY_READ") == 0)
1474 				entry->mask = MAY_READ;
1475 			else if (strcmp(from, "MAY_APPEND") == 0)
1476 				entry->mask = MAY_APPEND;
1477 			else
1478 				result = -EINVAL;
1479 			if (!result)
1480 				entry->flags |= (*args[0].from == '^')
1481 				     ? IMA_INMASK : IMA_MASK;
1482 			break;
1483 		case Opt_fsmagic:
1484 			ima_log_string(ab, "fsmagic", args[0].from);
1485 
1486 			if (entry->fsmagic) {
1487 				result = -EINVAL;
1488 				break;
1489 			}
1490 
1491 			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1492 			if (!result)
1493 				entry->flags |= IMA_FSMAGIC;
1494 			break;
1495 		case Opt_fsname:
1496 			ima_log_string(ab, "fsname", args[0].from);
1497 
1498 			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1499 			if (!entry->fsname) {
1500 				result = -ENOMEM;
1501 				break;
1502 			}
1503 			result = 0;
1504 			entry->flags |= IMA_FSNAME;
1505 			break;
1506 		case Opt_keyrings:
1507 			ima_log_string(ab, "keyrings", args[0].from);
1508 
1509 			if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1510 			    entry->keyrings) {
1511 				result = -EINVAL;
1512 				break;
1513 			}
1514 
1515 			entry->keyrings = ima_alloc_rule_opt_list(args);
1516 			if (IS_ERR(entry->keyrings)) {
1517 				result = PTR_ERR(entry->keyrings);
1518 				entry->keyrings = NULL;
1519 				break;
1520 			}
1521 
1522 			entry->flags |= IMA_KEYRINGS;
1523 			break;
1524 		case Opt_label:
1525 			ima_log_string(ab, "label", args[0].from);
1526 
1527 			if (entry->label) {
1528 				result = -EINVAL;
1529 				break;
1530 			}
1531 
1532 			entry->label = ima_alloc_rule_opt_list(args);
1533 			if (IS_ERR(entry->label)) {
1534 				result = PTR_ERR(entry->label);
1535 				entry->label = NULL;
1536 				break;
1537 			}
1538 
1539 			entry->flags |= IMA_LABEL;
1540 			break;
1541 		case Opt_fsuuid:
1542 			ima_log_string(ab, "fsuuid", args[0].from);
1543 
1544 			if (!uuid_is_null(&entry->fsuuid)) {
1545 				result = -EINVAL;
1546 				break;
1547 			}
1548 
1549 			result = uuid_parse(args[0].from, &entry->fsuuid);
1550 			if (!result)
1551 				entry->flags |= IMA_FSUUID;
1552 			break;
1553 		case Opt_uid_gt:
1554 		case Opt_euid_gt:
1555 			entry->uid_op = &uid_gt;
1556 			fallthrough;
1557 		case Opt_uid_lt:
1558 		case Opt_euid_lt:
1559 			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1560 				entry->uid_op = &uid_lt;
1561 			fallthrough;
1562 		case Opt_uid_eq:
1563 		case Opt_euid_eq:
1564 			eid_token = (token == Opt_euid_eq) ||
1565 				    (token == Opt_euid_gt) ||
1566 				    (token == Opt_euid_lt);
1567 
1568 			ima_log_string_op(ab, eid_token ? "euid" : "uid",
1569 					  args[0].from, token);
1570 
1571 			if (uid_valid(entry->uid)) {
1572 				result = -EINVAL;
1573 				break;
1574 			}
1575 
1576 			result = kstrtoul(args[0].from, 10, &lnum);
1577 			if (!result) {
1578 				entry->uid = make_kuid(current_user_ns(),
1579 						       (uid_t) lnum);
1580 				if (!uid_valid(entry->uid) ||
1581 				    (uid_t)lnum != lnum)
1582 					result = -EINVAL;
1583 				else
1584 					entry->flags |= eid_token
1585 					    ? IMA_EUID : IMA_UID;
1586 			}
1587 			break;
1588 		case Opt_gid_gt:
1589 		case Opt_egid_gt:
1590 			entry->gid_op = &gid_gt;
1591 			fallthrough;
1592 		case Opt_gid_lt:
1593 		case Opt_egid_lt:
1594 			if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1595 				entry->gid_op = &gid_lt;
1596 			fallthrough;
1597 		case Opt_gid_eq:
1598 		case Opt_egid_eq:
1599 			eid_token = (token == Opt_egid_eq) ||
1600 				    (token == Opt_egid_gt) ||
1601 				    (token == Opt_egid_lt);
1602 
1603 			ima_log_string_op(ab, eid_token ? "egid" : "gid",
1604 					  args[0].from, token);
1605 
1606 			if (gid_valid(entry->gid)) {
1607 				result = -EINVAL;
1608 				break;
1609 			}
1610 
1611 			result = kstrtoul(args[0].from, 10, &lnum);
1612 			if (!result) {
1613 				entry->gid = make_kgid(current_user_ns(),
1614 						       (gid_t)lnum);
1615 				if (!gid_valid(entry->gid) ||
1616 				    (((gid_t)lnum) != lnum))
1617 					result = -EINVAL;
1618 				else
1619 					entry->flags |= eid_token
1620 					    ? IMA_EGID : IMA_GID;
1621 			}
1622 			break;
1623 		case Opt_fowner_gt:
1624 			entry->fowner_op = &uid_gt;
1625 			fallthrough;
1626 		case Opt_fowner_lt:
1627 			if (token == Opt_fowner_lt)
1628 				entry->fowner_op = &uid_lt;
1629 			fallthrough;
1630 		case Opt_fowner_eq:
1631 			ima_log_string_op(ab, "fowner", args[0].from, token);
1632 
1633 			if (uid_valid(entry->fowner)) {
1634 				result = -EINVAL;
1635 				break;
1636 			}
1637 
1638 			result = kstrtoul(args[0].from, 10, &lnum);
1639 			if (!result) {
1640 				entry->fowner = make_kuid(current_user_ns(),
1641 							  (uid_t)lnum);
1642 				if (!uid_valid(entry->fowner) ||
1643 				    (((uid_t)lnum) != lnum))
1644 					result = -EINVAL;
1645 				else
1646 					entry->flags |= IMA_FOWNER;
1647 			}
1648 			break;
1649 		case Opt_fgroup_gt:
1650 			entry->fgroup_op = &gid_gt;
1651 			fallthrough;
1652 		case Opt_fgroup_lt:
1653 			if (token == Opt_fgroup_lt)
1654 				entry->fgroup_op = &gid_lt;
1655 			fallthrough;
1656 		case Opt_fgroup_eq:
1657 			ima_log_string_op(ab, "fgroup", args[0].from, token);
1658 
1659 			if (gid_valid(entry->fgroup)) {
1660 				result = -EINVAL;
1661 				break;
1662 			}
1663 
1664 			result = kstrtoul(args[0].from, 10, &lnum);
1665 			if (!result) {
1666 				entry->fgroup = make_kgid(current_user_ns(),
1667 							  (gid_t)lnum);
1668 				if (!gid_valid(entry->fgroup) ||
1669 				    (((gid_t)lnum) != lnum))
1670 					result = -EINVAL;
1671 				else
1672 					entry->flags |= IMA_FGROUP;
1673 			}
1674 			break;
1675 		case Opt_obj_user:
1676 			ima_log_string(ab, "obj_user", args[0].from);
1677 			result = ima_lsm_rule_init(entry, args,
1678 						   LSM_OBJ_USER,
1679 						   AUDIT_OBJ_USER);
1680 			break;
1681 		case Opt_obj_role:
1682 			ima_log_string(ab, "obj_role", args[0].from);
1683 			result = ima_lsm_rule_init(entry, args,
1684 						   LSM_OBJ_ROLE,
1685 						   AUDIT_OBJ_ROLE);
1686 			break;
1687 		case Opt_obj_type:
1688 			ima_log_string(ab, "obj_type", args[0].from);
1689 			result = ima_lsm_rule_init(entry, args,
1690 						   LSM_OBJ_TYPE,
1691 						   AUDIT_OBJ_TYPE);
1692 			break;
1693 		case Opt_subj_user:
1694 			ima_log_string(ab, "subj_user", args[0].from);
1695 			result = ima_lsm_rule_init(entry, args,
1696 						   LSM_SUBJ_USER,
1697 						   AUDIT_SUBJ_USER);
1698 			break;
1699 		case Opt_subj_role:
1700 			ima_log_string(ab, "subj_role", args[0].from);
1701 			result = ima_lsm_rule_init(entry, args,
1702 						   LSM_SUBJ_ROLE,
1703 						   AUDIT_SUBJ_ROLE);
1704 			break;
1705 		case Opt_subj_type:
1706 			ima_log_string(ab, "subj_type", args[0].from);
1707 			result = ima_lsm_rule_init(entry, args,
1708 						   LSM_SUBJ_TYPE,
1709 						   AUDIT_SUBJ_TYPE);
1710 			break;
1711 		case Opt_appraise_type:
1712 			ima_log_string(ab, "appraise_type", args[0].from);
1713 			if ((strcmp(args[0].from, "imasig")) == 0)
1714 				entry->flags |= IMA_DIGSIG_REQUIRED;
1715 			else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1716 				 strcmp(args[0].from, "imasig|modsig") == 0)
1717 				entry->flags |= IMA_DIGSIG_REQUIRED |
1718 						IMA_MODSIG_ALLOWED;
1719 			else
1720 				result = -EINVAL;
1721 			break;
1722 		case Opt_appraise_flag:
1723 			ima_log_string(ab, "appraise_flag", args[0].from);
1724 			if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1725 			    strstr(args[0].from, "blacklist"))
1726 				entry->flags |= IMA_CHECK_BLACKLIST;
1727 			else
1728 				result = -EINVAL;
1729 			break;
1730 		case Opt_appraise_algos:
1731 			ima_log_string(ab, "appraise_algos", args[0].from);
1732 
1733 			if (entry->allowed_algos) {
1734 				result = -EINVAL;
1735 				break;
1736 			}
1737 
1738 			entry->allowed_algos =
1739 				ima_parse_appraise_algos(args[0].from);
1740 			/* invalid or empty list of algorithms */
1741 			if (!entry->allowed_algos) {
1742 				result = -EINVAL;
1743 				break;
1744 			}
1745 
1746 			entry->flags |= IMA_VALIDATE_ALGOS;
1747 
1748 			break;
1749 		case Opt_permit_directio:
1750 			entry->flags |= IMA_PERMIT_DIRECTIO;
1751 			break;
1752 		case Opt_pcr:
1753 			ima_log_string(ab, "pcr", args[0].from);
1754 
1755 			result = kstrtoint(args[0].from, 10, &entry->pcr);
1756 			if (result || INVALID_PCR(entry->pcr))
1757 				result = -EINVAL;
1758 			else
1759 				entry->flags |= IMA_PCR;
1760 
1761 			break;
1762 		case Opt_template:
1763 			ima_log_string(ab, "template", args[0].from);
1764 			if (entry->action != MEASURE) {
1765 				result = -EINVAL;
1766 				break;
1767 			}
1768 			template_desc = lookup_template_desc(args[0].from);
1769 			if (!template_desc || entry->template) {
1770 				result = -EINVAL;
1771 				break;
1772 			}
1773 
1774 			/*
1775 			 * template_desc_init_fields() does nothing if
1776 			 * the template is already initialised, so
1777 			 * it's safe to do this unconditionally
1778 			 */
1779 			template_desc_init_fields(template_desc->fmt,
1780 						 &(template_desc->fields),
1781 						 &(template_desc->num_fields));
1782 			entry->template = template_desc;
1783 			break;
1784 		case Opt_err:
1785 			ima_log_string(ab, "UNKNOWN", p);
1786 			result = -EINVAL;
1787 			break;
1788 		}
1789 	}
1790 	if (!result && !ima_validate_rule(entry))
1791 		result = -EINVAL;
1792 	else if (entry->action == APPRAISE)
1793 		temp_ima_appraise |= ima_appraise_flag(entry->func);
1794 
1795 	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1796 		template_desc = entry->template ? entry->template :
1797 						  ima_template_desc_current();
1798 		check_template_modsig(template_desc);
1799 	}
1800 
1801 	audit_log_format(ab, "res=%d", !result);
1802 	audit_log_end(ab);
1803 	return result;
1804 }
1805 
1806 /**
1807  * ima_parse_add_rule - add a rule to ima_policy_rules
1808  * @rule - ima measurement policy rule
1809  *
1810  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1811  * Returns the length of the rule parsed, an error code on failure
1812  */
1813 ssize_t ima_parse_add_rule(char *rule)
1814 {
1815 	static const char op[] = "update_policy";
1816 	char *p;
1817 	struct ima_rule_entry *entry;
1818 	ssize_t result, len;
1819 	int audit_info = 0;
1820 
1821 	p = strsep(&rule, "\n");
1822 	len = strlen(p) + 1;
1823 	p += strspn(p, " \t");
1824 
1825 	if (*p == '#' || *p == '\0')
1826 		return len;
1827 
1828 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1829 	if (!entry) {
1830 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1831 				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1832 		return -ENOMEM;
1833 	}
1834 
1835 	INIT_LIST_HEAD(&entry->list);
1836 
1837 	result = ima_parse_rule(p, entry);
1838 	if (result) {
1839 		ima_free_rule(entry);
1840 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1841 				    NULL, op, "invalid-policy", result,
1842 				    audit_info);
1843 		return result;
1844 	}
1845 
1846 	list_add_tail(&entry->list, &ima_temp_rules);
1847 
1848 	return len;
1849 }
1850 
1851 /**
1852  * ima_delete_rules() called to cleanup invalid in-flight policy.
1853  * We don't need locking as we operate on the temp list, which is
1854  * different from the active one.  There is also only one user of
1855  * ima_delete_rules() at a time.
1856  */
1857 void ima_delete_rules(void)
1858 {
1859 	struct ima_rule_entry *entry, *tmp;
1860 
1861 	temp_ima_appraise = 0;
1862 	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1863 		list_del(&entry->list);
1864 		ima_free_rule(entry);
1865 	}
1866 }
1867 
1868 #define __ima_hook_stringify(func, str)	(#func),
1869 
1870 const char *const func_tokens[] = {
1871 	__ima_hooks(__ima_hook_stringify)
1872 };
1873 
1874 #ifdef	CONFIG_IMA_READ_POLICY
1875 enum {
1876 	mask_exec = 0, mask_write, mask_read, mask_append
1877 };
1878 
1879 static const char *const mask_tokens[] = {
1880 	"^MAY_EXEC",
1881 	"^MAY_WRITE",
1882 	"^MAY_READ",
1883 	"^MAY_APPEND"
1884 };
1885 
1886 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1887 {
1888 	loff_t l = *pos;
1889 	struct ima_rule_entry *entry;
1890 	struct list_head *ima_rules_tmp;
1891 
1892 	rcu_read_lock();
1893 	ima_rules_tmp = rcu_dereference(ima_rules);
1894 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
1895 		if (!l--) {
1896 			rcu_read_unlock();
1897 			return entry;
1898 		}
1899 	}
1900 	rcu_read_unlock();
1901 	return NULL;
1902 }
1903 
1904 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1905 {
1906 	struct ima_rule_entry *entry = v;
1907 
1908 	rcu_read_lock();
1909 	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1910 	rcu_read_unlock();
1911 	(*pos)++;
1912 
1913 	return (&entry->list == &ima_default_rules ||
1914 		&entry->list == &ima_policy_rules) ? NULL : entry;
1915 }
1916 
1917 void ima_policy_stop(struct seq_file *m, void *v)
1918 {
1919 }
1920 
1921 #define pt(token)	policy_tokens[token].pattern
1922 #define mt(token)	mask_tokens[token]
1923 
1924 /*
1925  * policy_func_show - display the ima_hooks policy rule
1926  */
1927 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1928 {
1929 	if (func > 0 && func < MAX_CHECK)
1930 		seq_printf(m, "func=%s ", func_tokens[func]);
1931 	else
1932 		seq_printf(m, "func=%d ", func);
1933 }
1934 
1935 static void ima_show_rule_opt_list(struct seq_file *m,
1936 				   const struct ima_rule_opt_list *opt_list)
1937 {
1938 	size_t i;
1939 
1940 	for (i = 0; i < opt_list->count; i++)
1941 		seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
1942 }
1943 
1944 static void ima_policy_show_appraise_algos(struct seq_file *m,
1945 					   unsigned int allowed_hashes)
1946 {
1947 	int idx, list_size = 0;
1948 
1949 	for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
1950 		if (!(allowed_hashes & (1U << idx)))
1951 			continue;
1952 
1953 		/* only add commas if the list contains multiple entries */
1954 		if (list_size++)
1955 			seq_puts(m, ",");
1956 
1957 		seq_puts(m, hash_algo_name[idx]);
1958 	}
1959 }
1960 
1961 int ima_policy_show(struct seq_file *m, void *v)
1962 {
1963 	struct ima_rule_entry *entry = v;
1964 	int i;
1965 	char tbuf[64] = {0,};
1966 	int offset = 0;
1967 
1968 	rcu_read_lock();
1969 
1970 	/* Do not print rules with inactive LSM labels */
1971 	for (i = 0; i < MAX_LSM_RULES; i++) {
1972 		if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
1973 			rcu_read_unlock();
1974 			return 0;
1975 		}
1976 	}
1977 
1978 	if (entry->action & MEASURE)
1979 		seq_puts(m, pt(Opt_measure));
1980 	if (entry->action & DONT_MEASURE)
1981 		seq_puts(m, pt(Opt_dont_measure));
1982 	if (entry->action & APPRAISE)
1983 		seq_puts(m, pt(Opt_appraise));
1984 	if (entry->action & DONT_APPRAISE)
1985 		seq_puts(m, pt(Opt_dont_appraise));
1986 	if (entry->action & AUDIT)
1987 		seq_puts(m, pt(Opt_audit));
1988 	if (entry->action & HASH)
1989 		seq_puts(m, pt(Opt_hash));
1990 	if (entry->action & DONT_HASH)
1991 		seq_puts(m, pt(Opt_dont_hash));
1992 
1993 	seq_puts(m, " ");
1994 
1995 	if (entry->flags & IMA_FUNC)
1996 		policy_func_show(m, entry->func);
1997 
1998 	if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1999 		if (entry->flags & IMA_MASK)
2000 			offset = 1;
2001 		if (entry->mask & MAY_EXEC)
2002 			seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2003 		if (entry->mask & MAY_WRITE)
2004 			seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2005 		if (entry->mask & MAY_READ)
2006 			seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2007 		if (entry->mask & MAY_APPEND)
2008 			seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2009 		seq_puts(m, " ");
2010 	}
2011 
2012 	if (entry->flags & IMA_FSMAGIC) {
2013 		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2014 		seq_printf(m, pt(Opt_fsmagic), tbuf);
2015 		seq_puts(m, " ");
2016 	}
2017 
2018 	if (entry->flags & IMA_FSNAME) {
2019 		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2020 		seq_printf(m, pt(Opt_fsname), tbuf);
2021 		seq_puts(m, " ");
2022 	}
2023 
2024 	if (entry->flags & IMA_KEYRINGS) {
2025 		seq_puts(m, "keyrings=");
2026 		ima_show_rule_opt_list(m, entry->keyrings);
2027 		seq_puts(m, " ");
2028 	}
2029 
2030 	if (entry->flags & IMA_LABEL) {
2031 		seq_puts(m, "label=");
2032 		ima_show_rule_opt_list(m, entry->label);
2033 		seq_puts(m, " ");
2034 	}
2035 
2036 	if (entry->flags & IMA_PCR) {
2037 		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2038 		seq_printf(m, pt(Opt_pcr), tbuf);
2039 		seq_puts(m, " ");
2040 	}
2041 
2042 	if (entry->flags & IMA_FSUUID) {
2043 		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2044 		seq_puts(m, " ");
2045 	}
2046 
2047 	if (entry->flags & IMA_UID) {
2048 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2049 		if (entry->uid_op == &uid_gt)
2050 			seq_printf(m, pt(Opt_uid_gt), tbuf);
2051 		else if (entry->uid_op == &uid_lt)
2052 			seq_printf(m, pt(Opt_uid_lt), tbuf);
2053 		else
2054 			seq_printf(m, pt(Opt_uid_eq), tbuf);
2055 		seq_puts(m, " ");
2056 	}
2057 
2058 	if (entry->flags & IMA_EUID) {
2059 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2060 		if (entry->uid_op == &uid_gt)
2061 			seq_printf(m, pt(Opt_euid_gt), tbuf);
2062 		else if (entry->uid_op == &uid_lt)
2063 			seq_printf(m, pt(Opt_euid_lt), tbuf);
2064 		else
2065 			seq_printf(m, pt(Opt_euid_eq), tbuf);
2066 		seq_puts(m, " ");
2067 	}
2068 
2069 	if (entry->flags & IMA_GID) {
2070 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2071 		if (entry->gid_op == &gid_gt)
2072 			seq_printf(m, pt(Opt_gid_gt), tbuf);
2073 		else if (entry->gid_op == &gid_lt)
2074 			seq_printf(m, pt(Opt_gid_lt), tbuf);
2075 		else
2076 			seq_printf(m, pt(Opt_gid_eq), tbuf);
2077 		seq_puts(m, " ");
2078 	}
2079 
2080 	if (entry->flags & IMA_EGID) {
2081 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2082 		if (entry->gid_op == &gid_gt)
2083 			seq_printf(m, pt(Opt_egid_gt), tbuf);
2084 		else if (entry->gid_op == &gid_lt)
2085 			seq_printf(m, pt(Opt_egid_lt), tbuf);
2086 		else
2087 			seq_printf(m, pt(Opt_egid_eq), tbuf);
2088 		seq_puts(m, " ");
2089 	}
2090 
2091 	if (entry->flags & IMA_FOWNER) {
2092 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2093 		if (entry->fowner_op == &uid_gt)
2094 			seq_printf(m, pt(Opt_fowner_gt), tbuf);
2095 		else if (entry->fowner_op == &uid_lt)
2096 			seq_printf(m, pt(Opt_fowner_lt), tbuf);
2097 		else
2098 			seq_printf(m, pt(Opt_fowner_eq), tbuf);
2099 		seq_puts(m, " ");
2100 	}
2101 
2102 	if (entry->flags & IMA_FGROUP) {
2103 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2104 		if (entry->fgroup_op == &gid_gt)
2105 			seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2106 		else if (entry->fgroup_op == &gid_lt)
2107 			seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2108 		else
2109 			seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2110 		seq_puts(m, " ");
2111 	}
2112 
2113 	if (entry->flags & IMA_VALIDATE_ALGOS) {
2114 		seq_puts(m, "appraise_algos=");
2115 		ima_policy_show_appraise_algos(m, entry->allowed_algos);
2116 		seq_puts(m, " ");
2117 	}
2118 
2119 	for (i = 0; i < MAX_LSM_RULES; i++) {
2120 		if (entry->lsm[i].rule) {
2121 			switch (i) {
2122 			case LSM_OBJ_USER:
2123 				seq_printf(m, pt(Opt_obj_user),
2124 					   entry->lsm[i].args_p);
2125 				break;
2126 			case LSM_OBJ_ROLE:
2127 				seq_printf(m, pt(Opt_obj_role),
2128 					   entry->lsm[i].args_p);
2129 				break;
2130 			case LSM_OBJ_TYPE:
2131 				seq_printf(m, pt(Opt_obj_type),
2132 					   entry->lsm[i].args_p);
2133 				break;
2134 			case LSM_SUBJ_USER:
2135 				seq_printf(m, pt(Opt_subj_user),
2136 					   entry->lsm[i].args_p);
2137 				break;
2138 			case LSM_SUBJ_ROLE:
2139 				seq_printf(m, pt(Opt_subj_role),
2140 					   entry->lsm[i].args_p);
2141 				break;
2142 			case LSM_SUBJ_TYPE:
2143 				seq_printf(m, pt(Opt_subj_type),
2144 					   entry->lsm[i].args_p);
2145 				break;
2146 			}
2147 			seq_puts(m, " ");
2148 		}
2149 	}
2150 	if (entry->template)
2151 		seq_printf(m, "template=%s ", entry->template->name);
2152 	if (entry->flags & IMA_DIGSIG_REQUIRED) {
2153 		if (entry->flags & IMA_MODSIG_ALLOWED)
2154 			seq_puts(m, "appraise_type=imasig|modsig ");
2155 		else
2156 			seq_puts(m, "appraise_type=imasig ");
2157 	}
2158 	if (entry->flags & IMA_CHECK_BLACKLIST)
2159 		seq_puts(m, "appraise_flag=check_blacklist ");
2160 	if (entry->flags & IMA_PERMIT_DIRECTIO)
2161 		seq_puts(m, "permit_directio ");
2162 	rcu_read_unlock();
2163 	seq_puts(m, "\n");
2164 	return 0;
2165 }
2166 #endif	/* CONFIG_IMA_READ_POLICY */
2167 
2168 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2169 /*
2170  * ima_appraise_signature: whether IMA will appraise a given function using
2171  * an IMA digital signature. This is restricted to cases where the kernel
2172  * has a set of built-in trusted keys in order to avoid an attacker simply
2173  * loading additional keys.
2174  */
2175 bool ima_appraise_signature(enum kernel_read_file_id id)
2176 {
2177 	struct ima_rule_entry *entry;
2178 	bool found = false;
2179 	enum ima_hooks func;
2180 	struct list_head *ima_rules_tmp;
2181 
2182 	if (id >= READING_MAX_ID)
2183 		return false;
2184 
2185 	func = read_idmap[id] ?: FILE_CHECK;
2186 
2187 	rcu_read_lock();
2188 	ima_rules_tmp = rcu_dereference(ima_rules);
2189 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2190 		if (entry->action != APPRAISE)
2191 			continue;
2192 
2193 		/*
2194 		 * A generic entry will match, but otherwise require that it
2195 		 * match the func we're looking for
2196 		 */
2197 		if (entry->func && entry->func != func)
2198 			continue;
2199 
2200 		/*
2201 		 * We require this to be a digital signature, not a raw IMA
2202 		 * hash.
2203 		 */
2204 		if (entry->flags & IMA_DIGSIG_REQUIRED)
2205 			found = true;
2206 
2207 		/*
2208 		 * We've found a rule that matches, so break now even if it
2209 		 * didn't require a digital signature - a later rule that does
2210 		 * won't override it, so would be a false positive.
2211 		 */
2212 		break;
2213 	}
2214 
2215 	rcu_read_unlock();
2216 	return found;
2217 }
2218 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
2219