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/seq_file.h>
20 #include <linux/ima.h>
21 
22 #include "ima.h"
23 
24 /* flags definitions */
25 #define IMA_FUNC	0x0001
26 #define IMA_MASK	0x0002
27 #define IMA_FSMAGIC	0x0004
28 #define IMA_UID		0x0008
29 #define IMA_FOWNER	0x0010
30 #define IMA_FSUUID	0x0020
31 #define IMA_INMASK	0x0040
32 #define IMA_EUID	0x0080
33 #define IMA_PCR		0x0100
34 #define IMA_FSNAME	0x0200
35 #define IMA_KEYRINGS	0x0400
36 #define IMA_LABEL	0x0800
37 #define IMA_VALIDATE_ALGOS	0x1000
38 #define IMA_GID		0x2000
39 #define IMA_EGID	0x4000
40 #define IMA_FGROUP	0x8000
41 
42 #define UNKNOWN		0
43 #define MEASURE		0x0001	/* same as IMA_MEASURE */
44 #define DONT_MEASURE	0x0002
45 #define APPRAISE	0x0004	/* same as IMA_APPRAISE */
46 #define DONT_APPRAISE	0x0008
47 #define AUDIT		0x0040
48 #define HASH		0x0100
49 #define DONT_HASH	0x0200
50 
51 #define INVALID_PCR(a) (((a) < 0) || \
52 	(a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
53 
54 int ima_policy_flag;
55 static int temp_ima_appraise;
56 static int build_ima_appraise __ro_after_init;
57 
58 atomic_t ima_setxattr_allowed_hash_algorithms;
59 
60 #define MAX_LSM_RULES 6
61 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
62 	LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
63 };
64 
65 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
66 
67 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
68 
69 struct ima_rule_opt_list {
70 	size_t count;
71 	char *items[];
72 };
73 
74 struct ima_rule_entry {
75 	struct list_head list;
76 	int action;
77 	unsigned int flags;
78 	enum ima_hooks func;
79 	int mask;
80 	unsigned long fsmagic;
81 	uuid_t fsuuid;
82 	kuid_t uid;
83 	kgid_t gid;
84 	kuid_t fowner;
85 	kgid_t fgroup;
86 	bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
87 	bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
88 	bool (*fowner_op)(kuid_t cred_uid, kuid_t rule_uid); /* uid_eq(), uid_gt(), uid_lt() */
89 	bool (*fgroup_op)(kgid_t cred_gid, kgid_t rule_gid); /* gid_eq(), gid_gt(), gid_lt() */
90 	int pcr;
91 	unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
92 	struct {
93 		void *rule;	/* LSM file metadata specific */
94 		char *args_p;	/* audit value */
95 		int type;	/* audit type */
96 	} lsm[MAX_LSM_RULES];
97 	char *fsname;
98 	struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
99 	struct ima_rule_opt_list *label; /* Measure data grouped under this label */
100 	struct ima_template_desc *template;
101 };
102 
103 /*
104  * sanity check in case the kernels gains more hash algorithms that can
105  * fit in an unsigned int
106  */
107 static_assert(
108 	8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
109 	"The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
110 
111 /*
112  * Without LSM specific knowledge, the default policy can only be
113  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
114  * .fowner, and .fgroup
115  */
116 
117 /*
118  * The minimum rule set to allow for full TCB coverage.  Measures all files
119  * opened or mmap for exec and everything read by root.  Dangerous because
120  * normal users can easily run the machine out of memory simply building
121  * and running executables.
122  */
123 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
124 	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
125 	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
126 	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
127 	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
128 	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
129 	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
130 	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
131 	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
132 	{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
133 	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
134 	 .flags = IMA_FSMAGIC},
135 	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
136 	 .flags = IMA_FSMAGIC},
137 	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
138 	{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
139 };
140 
141 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
142 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
143 	 .flags = IMA_FUNC | IMA_MASK},
144 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
145 	 .flags = IMA_FUNC | IMA_MASK},
146 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
147 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
148 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
149 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
150 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
151 };
152 
153 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
154 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
155 	 .flags = IMA_FUNC | IMA_MASK},
156 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
157 	 .flags = IMA_FUNC | IMA_MASK},
158 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
159 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
160 	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
161 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
162 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
163 	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
164 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
165 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
166 	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
167 };
168 
169 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
170 	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
171 	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
172 	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
173 	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
174 	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
175 	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
176 	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
177 	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
178 	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
179 	{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
180 	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
181 	{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
182 	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
183 	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
184 #ifdef CONFIG_IMA_WRITE_POLICY
185 	{.action = APPRAISE, .func = POLICY_CHECK,
186 	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
187 #endif
188 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
189 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
190 	 .flags = IMA_FOWNER},
191 #else
192 	/* force signature */
193 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
194 	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
195 #endif
196 };
197 
198 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
199 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
200 	{.action = APPRAISE, .func = MODULE_CHECK,
201 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
202 #endif
203 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
204 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
205 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
206 #endif
207 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
208 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
209 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
210 #endif
211 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
212 	{.action = APPRAISE, .func = POLICY_CHECK,
213 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
214 #endif
215 };
216 
217 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
218 	{.action = APPRAISE, .func = MODULE_CHECK,
219 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
220 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
221 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
222 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
223 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
224 	{.action = APPRAISE, .func = POLICY_CHECK,
225 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
226 };
227 
228 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
229 	{.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
230 };
231 
232 /* An array of architecture specific rules */
233 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
234 
235 static LIST_HEAD(ima_default_rules);
236 static LIST_HEAD(ima_policy_rules);
237 static LIST_HEAD(ima_temp_rules);
238 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
239 
240 static int ima_policy __initdata;
241 
242 static int __init default_measure_policy_setup(char *str)
243 {
244 	if (ima_policy)
245 		return 1;
246 
247 	ima_policy = ORIGINAL_TCB;
248 	return 1;
249 }
250 __setup("ima_tcb", default_measure_policy_setup);
251 
252 static bool ima_use_appraise_tcb __initdata;
253 static bool ima_use_secure_boot __initdata;
254 static bool ima_use_critical_data __initdata;
255 static bool ima_fail_unverifiable_sigs __ro_after_init;
256 static int __init policy_setup(char *str)
257 {
258 	char *p;
259 
260 	while ((p = strsep(&str, " |\n")) != NULL) {
261 		if (*p == ' ')
262 			continue;
263 		if ((strcmp(p, "tcb") == 0) && !ima_policy)
264 			ima_policy = DEFAULT_TCB;
265 		else if (strcmp(p, "appraise_tcb") == 0)
266 			ima_use_appraise_tcb = true;
267 		else if (strcmp(p, "secure_boot") == 0)
268 			ima_use_secure_boot = true;
269 		else if (strcmp(p, "critical_data") == 0)
270 			ima_use_critical_data = true;
271 		else if (strcmp(p, "fail_securely") == 0)
272 			ima_fail_unverifiable_sigs = true;
273 		else
274 			pr_err("policy \"%s\" not found", p);
275 	}
276 
277 	return 1;
278 }
279 __setup("ima_policy=", policy_setup);
280 
281 static int __init default_appraise_policy_setup(char *str)
282 {
283 	ima_use_appraise_tcb = true;
284 	return 1;
285 }
286 __setup("ima_appraise_tcb", default_appraise_policy_setup);
287 
288 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
289 {
290 	struct ima_rule_opt_list *opt_list;
291 	size_t count = 0;
292 	char *src_copy;
293 	char *cur, *next;
294 	size_t i;
295 
296 	src_copy = match_strdup(src);
297 	if (!src_copy)
298 		return ERR_PTR(-ENOMEM);
299 
300 	next = src_copy;
301 	while ((cur = strsep(&next, "|"))) {
302 		/* Don't accept an empty list item */
303 		if (!(*cur)) {
304 			kfree(src_copy);
305 			return ERR_PTR(-EINVAL);
306 		}
307 		count++;
308 	}
309 
310 	/* Don't accept an empty list */
311 	if (!count) {
312 		kfree(src_copy);
313 		return ERR_PTR(-EINVAL);
314 	}
315 
316 	opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
317 	if (!opt_list) {
318 		kfree(src_copy);
319 		return ERR_PTR(-ENOMEM);
320 	}
321 
322 	/*
323 	 * strsep() has already replaced all instances of '|' with '\0',
324 	 * leaving a byte sequence of NUL-terminated strings. Reference each
325 	 * string with the array of items.
326 	 *
327 	 * IMPORTANT: Ownership of the allocated buffer is transferred from
328 	 * src_copy to the first element in the items array. To free the
329 	 * buffer, kfree() must only be called on the first element of the
330 	 * array.
331 	 */
332 	for (i = 0, cur = src_copy; i < count; i++) {
333 		opt_list->items[i] = cur;
334 		cur = strchr(cur, '\0') + 1;
335 	}
336 	opt_list->count = count;
337 
338 	return opt_list;
339 }
340 
341 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
342 {
343 	if (!opt_list)
344 		return;
345 
346 	if (opt_list->count) {
347 		kfree(opt_list->items[0]);
348 		opt_list->count = 0;
349 	}
350 
351 	kfree(opt_list);
352 }
353 
354 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
355 {
356 	int i;
357 
358 	for (i = 0; i < MAX_LSM_RULES; i++) {
359 		ima_filter_rule_free(entry->lsm[i].rule);
360 		kfree(entry->lsm[i].args_p);
361 	}
362 }
363 
364 static void ima_free_rule(struct ima_rule_entry *entry)
365 {
366 	if (!entry)
367 		return;
368 
369 	/*
370 	 * entry->template->fields may be allocated in ima_parse_rule() but that
371 	 * reference is owned by the corresponding ima_template_desc element in
372 	 * the defined_templates list and cannot be freed here
373 	 */
374 	kfree(entry->fsname);
375 	ima_free_rule_opt_list(entry->keyrings);
376 	ima_lsm_free_rule(entry);
377 	kfree(entry);
378 }
379 
380 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
381 {
382 	struct ima_rule_entry *nentry;
383 	int i;
384 
385 	/*
386 	 * Immutable elements are copied over as pointers and data; only
387 	 * lsm rules can change
388 	 */
389 	nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
390 	if (!nentry)
391 		return NULL;
392 
393 	memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
394 
395 	for (i = 0; i < MAX_LSM_RULES; i++) {
396 		if (!entry->lsm[i].args_p)
397 			continue;
398 
399 		nentry->lsm[i].type = entry->lsm[i].type;
400 		nentry->lsm[i].args_p = entry->lsm[i].args_p;
401 		/*
402 		 * Remove the reference from entry so that the associated
403 		 * memory will not be freed during a later call to
404 		 * ima_lsm_free_rule(entry).
405 		 */
406 		entry->lsm[i].args_p = NULL;
407 
408 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
409 				     nentry->lsm[i].args_p,
410 				     &nentry->lsm[i].rule);
411 		if (!nentry->lsm[i].rule)
412 			pr_warn("rule for LSM \'%s\' is undefined\n",
413 				nentry->lsm[i].args_p);
414 	}
415 	return nentry;
416 }
417 
418 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
419 {
420 	struct ima_rule_entry *nentry;
421 
422 	nentry = ima_lsm_copy_rule(entry);
423 	if (!nentry)
424 		return -ENOMEM;
425 
426 	list_replace_rcu(&entry->list, &nentry->list);
427 	synchronize_rcu();
428 	/*
429 	 * ima_lsm_copy_rule() shallow copied all references, except for the
430 	 * LSM references, from entry to nentry so we only want to free the LSM
431 	 * references and the entry itself. All other memory references will now
432 	 * be owned by nentry.
433 	 */
434 	ima_lsm_free_rule(entry);
435 	kfree(entry);
436 
437 	return 0;
438 }
439 
440 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
441 {
442 	int i;
443 
444 	for (i = 0; i < MAX_LSM_RULES; i++)
445 		if (entry->lsm[i].args_p)
446 			return true;
447 
448 	return false;
449 }
450 
451 /*
452  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
453  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
454  * the reloaded LSM policy.
455  */
456 static void ima_lsm_update_rules(void)
457 {
458 	struct ima_rule_entry *entry, *e;
459 	int result;
460 
461 	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
462 		if (!ima_rule_contains_lsm_cond(entry))
463 			continue;
464 
465 		result = ima_lsm_update_rule(entry);
466 		if (result) {
467 			pr_err("lsm rule update error %d\n", result);
468 			return;
469 		}
470 	}
471 }
472 
473 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
474 			  void *lsm_data)
475 {
476 	if (event != LSM_POLICY_CHANGE)
477 		return NOTIFY_DONE;
478 
479 	ima_lsm_update_rules();
480 	return NOTIFY_OK;
481 }
482 
483 /**
484  * ima_match_rule_data - determine whether func_data matches the policy rule
485  * @rule: a pointer to a rule
486  * @func_data: data to match against the measure rule data
487  * @cred: a pointer to a credentials structure for user validation
488  *
489  * Returns true if func_data matches one in the rule, false otherwise.
490  */
491 static bool ima_match_rule_data(struct ima_rule_entry *rule,
492 				const char *func_data,
493 				const struct cred *cred)
494 {
495 	const struct ima_rule_opt_list *opt_list = NULL;
496 	bool matched = false;
497 	size_t i;
498 
499 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
500 		return false;
501 
502 	switch (rule->func) {
503 	case KEY_CHECK:
504 		if (!rule->keyrings)
505 			return true;
506 
507 		opt_list = rule->keyrings;
508 		break;
509 	case CRITICAL_DATA:
510 		if (!rule->label)
511 			return true;
512 
513 		opt_list = rule->label;
514 		break;
515 	default:
516 		return false;
517 	}
518 
519 	if (!func_data)
520 		return false;
521 
522 	for (i = 0; i < opt_list->count; i++) {
523 		if (!strcmp(opt_list->items[i], func_data)) {
524 			matched = true;
525 			break;
526 		}
527 	}
528 
529 	return matched;
530 }
531 
532 /**
533  * ima_match_rules - determine whether an inode matches the policy rule.
534  * @rule: a pointer to a rule
535  * @mnt_userns:	user namespace of the mount the inode was found from
536  * @inode: a pointer to an inode
537  * @cred: a pointer to a credentials structure for user validation
538  * @secid: the secid of the task to be validated
539  * @func: LIM hook identifier
540  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
541  * @func_data: func specific data, may be NULL
542  *
543  * Returns true on rule match, false on failure.
544  */
545 static bool ima_match_rules(struct ima_rule_entry *rule,
546 			    struct user_namespace *mnt_userns,
547 			    struct inode *inode, const struct cred *cred,
548 			    u32 secid, enum ima_hooks func, int mask,
549 			    const char *func_data)
550 {
551 	int i;
552 
553 	if ((rule->flags & IMA_FUNC) &&
554 	    (rule->func != func && func != POST_SETATTR))
555 		return false;
556 
557 	switch (func) {
558 	case KEY_CHECK:
559 	case CRITICAL_DATA:
560 		return ((rule->func == func) &&
561 			ima_match_rule_data(rule, func_data, cred));
562 	default:
563 		break;
564 	}
565 
566 	if ((rule->flags & IMA_MASK) &&
567 	    (rule->mask != mask && func != POST_SETATTR))
568 		return false;
569 	if ((rule->flags & IMA_INMASK) &&
570 	    (!(rule->mask & mask) && func != POST_SETATTR))
571 		return false;
572 	if ((rule->flags & IMA_FSMAGIC)
573 	    && rule->fsmagic != inode->i_sb->s_magic)
574 		return false;
575 	if ((rule->flags & IMA_FSNAME)
576 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
577 		return false;
578 	if ((rule->flags & IMA_FSUUID) &&
579 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
580 		return false;
581 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
582 		return false;
583 	if (rule->flags & IMA_EUID) {
584 		if (has_capability_noaudit(current, CAP_SETUID)) {
585 			if (!rule->uid_op(cred->euid, rule->uid)
586 			    && !rule->uid_op(cred->suid, rule->uid)
587 			    && !rule->uid_op(cred->uid, rule->uid))
588 				return false;
589 		} else if (!rule->uid_op(cred->euid, rule->uid))
590 			return false;
591 	}
592 	if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
593 		return false;
594 	if (rule->flags & IMA_EGID) {
595 		if (has_capability_noaudit(current, CAP_SETGID)) {
596 			if (!rule->gid_op(cred->egid, rule->gid)
597 			    && !rule->gid_op(cred->sgid, rule->gid)
598 			    && !rule->gid_op(cred->gid, rule->gid))
599 				return false;
600 		} else if (!rule->gid_op(cred->egid, rule->gid))
601 			return false;
602 	}
603 	if ((rule->flags & IMA_FOWNER) &&
604 	    !rule->fowner_op(i_uid_into_mnt(mnt_userns, inode), rule->fowner))
605 		return false;
606 	if ((rule->flags & IMA_FGROUP) &&
607 	    !rule->fgroup_op(i_gid_into_mnt(mnt_userns, inode), rule->fgroup))
608 		return false;
609 	for (i = 0; i < MAX_LSM_RULES; i++) {
610 		int rc = 0;
611 		u32 osid;
612 
613 		if (!rule->lsm[i].rule) {
614 			if (!rule->lsm[i].args_p)
615 				continue;
616 			else
617 				return false;
618 		}
619 		switch (i) {
620 		case LSM_OBJ_USER:
621 		case LSM_OBJ_ROLE:
622 		case LSM_OBJ_TYPE:
623 			security_inode_getsecid(inode, &osid);
624 			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
625 						   Audit_equal,
626 						   rule->lsm[i].rule);
627 			break;
628 		case LSM_SUBJ_USER:
629 		case LSM_SUBJ_ROLE:
630 		case LSM_SUBJ_TYPE:
631 			rc = ima_filter_rule_match(secid, rule->lsm[i].type,
632 						   Audit_equal,
633 						   rule->lsm[i].rule);
634 			break;
635 		default:
636 			break;
637 		}
638 		if (!rc)
639 			return false;
640 	}
641 	return true;
642 }
643 
644 /*
645  * In addition to knowing that we need to appraise the file in general,
646  * we need to differentiate between calling hooks, for hook specific rules.
647  */
648 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
649 {
650 	if (!(rule->flags & IMA_FUNC))
651 		return IMA_FILE_APPRAISE;
652 
653 	switch (func) {
654 	case MMAP_CHECK:
655 		return IMA_MMAP_APPRAISE;
656 	case BPRM_CHECK:
657 		return IMA_BPRM_APPRAISE;
658 	case CREDS_CHECK:
659 		return IMA_CREDS_APPRAISE;
660 	case FILE_CHECK:
661 	case POST_SETATTR:
662 		return IMA_FILE_APPRAISE;
663 	case MODULE_CHECK ... MAX_CHECK - 1:
664 	default:
665 		return IMA_READ_APPRAISE;
666 	}
667 }
668 
669 /**
670  * ima_match_policy - decision based on LSM and other conditions
671  * @mnt_userns:	user namespace of the mount the inode was found from
672  * @inode: pointer to an inode for which the policy decision is being made
673  * @cred: pointer to a credentials structure for which the policy decision is
674  *        being made
675  * @secid: LSM secid of the task to be validated
676  * @func: IMA hook identifier
677  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
678  * @pcr: set the pcr to extend
679  * @template_desc: the template that should be used for this rule
680  * @func_data: func specific data, may be NULL
681  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
682  *
683  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
684  * conditions.
685  *
686  * Since the IMA policy may be updated multiple times we need to lock the
687  * list when walking it.  Reads are many orders of magnitude more numerous
688  * than writes so ima_match_policy() is classical RCU candidate.
689  */
690 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
691 		     const struct cred *cred, u32 secid, enum ima_hooks func,
692 		     int mask, int flags, int *pcr,
693 		     struct ima_template_desc **template_desc,
694 		     const char *func_data, unsigned int *allowed_algos)
695 {
696 	struct ima_rule_entry *entry;
697 	int action = 0, actmask = flags | (flags << 1);
698 	struct list_head *ima_rules_tmp;
699 
700 	if (template_desc && !*template_desc)
701 		*template_desc = ima_template_desc_current();
702 
703 	rcu_read_lock();
704 	ima_rules_tmp = rcu_dereference(ima_rules);
705 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
706 
707 		if (!(entry->action & actmask))
708 			continue;
709 
710 		if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
711 				     func, mask, func_data))
712 			continue;
713 
714 		action |= entry->flags & IMA_NONACTION_FLAGS;
715 
716 		action |= entry->action & IMA_DO_MASK;
717 		if (entry->action & IMA_APPRAISE) {
718 			action |= get_subaction(entry, func);
719 			action &= ~IMA_HASH;
720 			if (ima_fail_unverifiable_sigs)
721 				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
722 
723 			if (allowed_algos &&
724 			    entry->flags & IMA_VALIDATE_ALGOS)
725 				*allowed_algos = entry->allowed_algos;
726 		}
727 
728 		if (entry->action & IMA_DO_MASK)
729 			actmask &= ~(entry->action | entry->action << 1);
730 		else
731 			actmask &= ~(entry->action | entry->action >> 1);
732 
733 		if ((pcr) && (entry->flags & IMA_PCR))
734 			*pcr = entry->pcr;
735 
736 		if (template_desc && entry->template)
737 			*template_desc = entry->template;
738 
739 		if (!actmask)
740 			break;
741 	}
742 	rcu_read_unlock();
743 
744 	return action;
745 }
746 
747 /**
748  * ima_update_policy_flags() - Update global IMA variables
749  *
750  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
751  * based on the currently loaded policy.
752  *
753  * With ima_policy_flag, the decision to short circuit out of a function
754  * or not call the function in the first place can be made earlier.
755  *
756  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
757  * set of hash algorithms accepted when updating the security.ima xattr of
758  * a file.
759  *
760  * Context: called after a policy update and at system initialization.
761  */
762 void ima_update_policy_flags(void)
763 {
764 	struct ima_rule_entry *entry;
765 	int new_policy_flag = 0;
766 	struct list_head *ima_rules_tmp;
767 
768 	rcu_read_lock();
769 	ima_rules_tmp = rcu_dereference(ima_rules);
770 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
771 		/*
772 		 * SETXATTR_CHECK rules do not implement a full policy check
773 		 * because rule checking would probably have an important
774 		 * performance impact on setxattr(). As a consequence, only one
775 		 * SETXATTR_CHECK can be active at a given time.
776 		 * Because we want to preserve that property, we set out to use
777 		 * atomic_cmpxchg. Either:
778 		 * - the atomic was non-zero: a setxattr hash policy is
779 		 *   already enforced, we do nothing
780 		 * - the atomic was zero: no setxattr policy was set, enable
781 		 *   the setxattr hash policy
782 		 */
783 		if (entry->func == SETXATTR_CHECK) {
784 			atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
785 				       0, entry->allowed_algos);
786 			/* SETXATTR_CHECK doesn't impact ima_policy_flag */
787 			continue;
788 		}
789 
790 		if (entry->action & IMA_DO_MASK)
791 			new_policy_flag |= entry->action;
792 	}
793 	rcu_read_unlock();
794 
795 	ima_appraise |= (build_ima_appraise | temp_ima_appraise);
796 	if (!ima_appraise)
797 		new_policy_flag &= ~IMA_APPRAISE;
798 
799 	ima_policy_flag = new_policy_flag;
800 }
801 
802 static int ima_appraise_flag(enum ima_hooks func)
803 {
804 	if (func == MODULE_CHECK)
805 		return IMA_APPRAISE_MODULES;
806 	else if (func == FIRMWARE_CHECK)
807 		return IMA_APPRAISE_FIRMWARE;
808 	else if (func == POLICY_CHECK)
809 		return IMA_APPRAISE_POLICY;
810 	else if (func == KEXEC_KERNEL_CHECK)
811 		return IMA_APPRAISE_KEXEC;
812 	return 0;
813 }
814 
815 static void add_rules(struct ima_rule_entry *entries, int count,
816 		      enum policy_rule_list policy_rule)
817 {
818 	int i = 0;
819 
820 	for (i = 0; i < count; i++) {
821 		struct ima_rule_entry *entry;
822 
823 		if (policy_rule & IMA_DEFAULT_POLICY)
824 			list_add_tail(&entries[i].list, &ima_default_rules);
825 
826 		if (policy_rule & IMA_CUSTOM_POLICY) {
827 			entry = kmemdup(&entries[i], sizeof(*entry),
828 					GFP_KERNEL);
829 			if (!entry)
830 				continue;
831 
832 			list_add_tail(&entry->list, &ima_policy_rules);
833 		}
834 		if (entries[i].action == APPRAISE) {
835 			if (entries != build_appraise_rules)
836 				temp_ima_appraise |=
837 					ima_appraise_flag(entries[i].func);
838 			else
839 				build_ima_appraise |=
840 					ima_appraise_flag(entries[i].func);
841 		}
842 	}
843 }
844 
845 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
846 
847 static int __init ima_init_arch_policy(void)
848 {
849 	const char * const *arch_rules;
850 	const char * const *rules;
851 	int arch_entries = 0;
852 	int i = 0;
853 
854 	arch_rules = arch_get_ima_policy();
855 	if (!arch_rules)
856 		return arch_entries;
857 
858 	/* Get number of rules */
859 	for (rules = arch_rules; *rules != NULL; rules++)
860 		arch_entries++;
861 
862 	arch_policy_entry = kcalloc(arch_entries + 1,
863 				    sizeof(*arch_policy_entry), GFP_KERNEL);
864 	if (!arch_policy_entry)
865 		return 0;
866 
867 	/* Convert each policy string rules to struct ima_rule_entry format */
868 	for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
869 		char rule[255];
870 		int result;
871 
872 		result = strscpy(rule, *rules, sizeof(rule));
873 
874 		INIT_LIST_HEAD(&arch_policy_entry[i].list);
875 		result = ima_parse_rule(rule, &arch_policy_entry[i]);
876 		if (result) {
877 			pr_warn("Skipping unknown architecture policy rule: %s\n",
878 				rule);
879 			memset(&arch_policy_entry[i], 0,
880 			       sizeof(*arch_policy_entry));
881 			continue;
882 		}
883 		i++;
884 	}
885 	return i;
886 }
887 
888 /**
889  * ima_init_policy - initialize the default measure rules.
890  *
891  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
892  */
893 void __init ima_init_policy(void)
894 {
895 	int build_appraise_entries, arch_entries;
896 
897 	/* if !ima_policy, we load NO default rules */
898 	if (ima_policy)
899 		add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
900 			  IMA_DEFAULT_POLICY);
901 
902 	switch (ima_policy) {
903 	case ORIGINAL_TCB:
904 		add_rules(original_measurement_rules,
905 			  ARRAY_SIZE(original_measurement_rules),
906 			  IMA_DEFAULT_POLICY);
907 		break;
908 	case DEFAULT_TCB:
909 		add_rules(default_measurement_rules,
910 			  ARRAY_SIZE(default_measurement_rules),
911 			  IMA_DEFAULT_POLICY);
912 		break;
913 	default:
914 		break;
915 	}
916 
917 	/*
918 	 * Based on runtime secure boot flags, insert arch specific measurement
919 	 * and appraise rules requiring file signatures for both the initial
920 	 * and custom policies, prior to other appraise rules.
921 	 * (Highest priority)
922 	 */
923 	arch_entries = ima_init_arch_policy();
924 	if (!arch_entries)
925 		pr_info("No architecture policies found\n");
926 	else
927 		add_rules(arch_policy_entry, arch_entries,
928 			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
929 
930 	/*
931 	 * Insert the builtin "secure_boot" policy rules requiring file
932 	 * signatures, prior to other appraise rules.
933 	 */
934 	if (ima_use_secure_boot)
935 		add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
936 			  IMA_DEFAULT_POLICY);
937 
938 	/*
939 	 * Insert the build time appraise rules requiring file signatures
940 	 * for both the initial and custom policies, prior to other appraise
941 	 * rules. As the secure boot rules includes all of the build time
942 	 * rules, include either one or the other set of rules, but not both.
943 	 */
944 	build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
945 	if (build_appraise_entries) {
946 		if (ima_use_secure_boot)
947 			add_rules(build_appraise_rules, build_appraise_entries,
948 				  IMA_CUSTOM_POLICY);
949 		else
950 			add_rules(build_appraise_rules, build_appraise_entries,
951 				  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
952 	}
953 
954 	if (ima_use_appraise_tcb)
955 		add_rules(default_appraise_rules,
956 			  ARRAY_SIZE(default_appraise_rules),
957 			  IMA_DEFAULT_POLICY);
958 
959 	if (ima_use_critical_data)
960 		add_rules(critical_data_rules,
961 			  ARRAY_SIZE(critical_data_rules),
962 			  IMA_DEFAULT_POLICY);
963 
964 	atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
965 
966 	ima_update_policy_flags();
967 }
968 
969 /* Make sure we have a valid policy, at least containing some rules. */
970 int ima_check_policy(void)
971 {
972 	if (list_empty(&ima_temp_rules))
973 		return -EINVAL;
974 	return 0;
975 }
976 
977 /**
978  * ima_update_policy - update default_rules with new measure rules
979  *
980  * Called on file .release to update the default rules with a complete new
981  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
982  * they make a queue.  The policy may be updated multiple times and this is the
983  * RCU updater.
984  *
985  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
986  * we switch from the default policy to user defined.
987  */
988 void ima_update_policy(void)
989 {
990 	struct list_head *policy = &ima_policy_rules;
991 
992 	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
993 
994 	if (ima_rules != (struct list_head __rcu *)policy) {
995 		ima_policy_flag = 0;
996 
997 		rcu_assign_pointer(ima_rules, policy);
998 		/*
999 		 * IMA architecture specific policy rules are specified
1000 		 * as strings and converted to an array of ima_entry_rules
1001 		 * on boot.  After loading a custom policy, free the
1002 		 * architecture specific rules stored as an array.
1003 		 */
1004 		kfree(arch_policy_entry);
1005 	}
1006 	ima_update_policy_flags();
1007 
1008 	/* Custom IMA policy has been loaded */
1009 	ima_process_queued_keys();
1010 }
1011 
1012 /* Keep the enumeration in sync with the policy_tokens! */
1013 enum policy_opt {
1014 	Opt_measure, Opt_dont_measure,
1015 	Opt_appraise, Opt_dont_appraise,
1016 	Opt_audit, Opt_hash, Opt_dont_hash,
1017 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
1018 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
1019 	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1020 	Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1021 	Opt_fowner_eq, Opt_fgroup_eq,
1022 	Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1023 	Opt_fowner_gt, Opt_fgroup_gt,
1024 	Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1025 	Opt_fowner_lt, Opt_fgroup_lt,
1026 	Opt_digest_type,
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_digest_type, "digest_type=%s"},
1070 	{Opt_appraise_type, "appraise_type=%s"},
1071 	{Opt_appraise_flag, "appraise_flag=%s"},
1072 	{Opt_appraise_algos, "appraise_algos=%s"},
1073 	{Opt_permit_directio, "permit_directio"},
1074 	{Opt_pcr, "pcr=%s"},
1075 	{Opt_template, "template=%s"},
1076 	{Opt_keyrings, "keyrings=%s"},
1077 	{Opt_label, "label=%s"},
1078 	{Opt_err, NULL}
1079 };
1080 
1081 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1082 			     substring_t *args, int lsm_rule, int audit_type)
1083 {
1084 	int result;
1085 
1086 	if (entry->lsm[lsm_rule].rule)
1087 		return -EINVAL;
1088 
1089 	entry->lsm[lsm_rule].args_p = match_strdup(args);
1090 	if (!entry->lsm[lsm_rule].args_p)
1091 		return -ENOMEM;
1092 
1093 	entry->lsm[lsm_rule].type = audit_type;
1094 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1095 				      entry->lsm[lsm_rule].args_p,
1096 				      &entry->lsm[lsm_rule].rule);
1097 	if (!entry->lsm[lsm_rule].rule) {
1098 		pr_warn("rule for LSM \'%s\' is undefined\n",
1099 			entry->lsm[lsm_rule].args_p);
1100 
1101 		if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1102 			kfree(entry->lsm[lsm_rule].args_p);
1103 			entry->lsm[lsm_rule].args_p = NULL;
1104 			result = -EINVAL;
1105 		} else
1106 			result = 0;
1107 	}
1108 
1109 	return result;
1110 }
1111 
1112 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1113 			      enum policy_opt rule_operator)
1114 {
1115 	if (!ab)
1116 		return;
1117 
1118 	switch (rule_operator) {
1119 	case Opt_uid_gt:
1120 	case Opt_euid_gt:
1121 	case Opt_gid_gt:
1122 	case Opt_egid_gt:
1123 	case Opt_fowner_gt:
1124 	case Opt_fgroup_gt:
1125 		audit_log_format(ab, "%s>", key);
1126 		break;
1127 	case Opt_uid_lt:
1128 	case Opt_euid_lt:
1129 	case Opt_gid_lt:
1130 	case Opt_egid_lt:
1131 	case Opt_fowner_lt:
1132 	case Opt_fgroup_lt:
1133 		audit_log_format(ab, "%s<", key);
1134 		break;
1135 	default:
1136 		audit_log_format(ab, "%s=", key);
1137 	}
1138 	audit_log_format(ab, "%s ", value);
1139 }
1140 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1141 {
1142 	ima_log_string_op(ab, key, value, Opt_err);
1143 }
1144 
1145 /*
1146  * Validating the appended signature included in the measurement list requires
1147  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1148  * field). Therefore, notify the user if they have the 'modsig' field but not
1149  * the 'd-modsig' field in the template.
1150  */
1151 static void check_template_modsig(const struct ima_template_desc *template)
1152 {
1153 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1154 	bool has_modsig, has_dmodsig;
1155 	static bool checked;
1156 	int i;
1157 
1158 	/* We only need to notify the user once. */
1159 	if (checked)
1160 		return;
1161 
1162 	has_modsig = has_dmodsig = false;
1163 	for (i = 0; i < template->num_fields; i++) {
1164 		if (!strcmp(template->fields[i]->field_id, "modsig"))
1165 			has_modsig = true;
1166 		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1167 			has_dmodsig = true;
1168 	}
1169 
1170 	if (has_modsig && !has_dmodsig)
1171 		pr_notice(MSG);
1172 
1173 	checked = true;
1174 #undef MSG
1175 }
1176 
1177 /*
1178  * Warn if the template does not contain the given field.
1179  */
1180 static void check_template_field(const struct ima_template_desc *template,
1181 				 const char *field, const char *msg)
1182 {
1183 	int i;
1184 
1185 	for (i = 0; i < template->num_fields; i++)
1186 		if (!strcmp(template->fields[i]->field_id, field))
1187 			return;
1188 
1189 	pr_notice_once("%s", msg);
1190 }
1191 
1192 static bool ima_validate_rule(struct ima_rule_entry *entry)
1193 {
1194 	/* Ensure that the action is set and is compatible with the flags */
1195 	if (entry->action == UNKNOWN)
1196 		return false;
1197 
1198 	if (entry->action != MEASURE && entry->flags & IMA_PCR)
1199 		return false;
1200 
1201 	if (entry->action != APPRAISE &&
1202 	    entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1203 			    IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1204 		return false;
1205 
1206 	/*
1207 	 * The IMA_FUNC bit must be set if and only if there's a valid hook
1208 	 * function specified, and vice versa. Enforcing this property allows
1209 	 * for the NONE case below to validate a rule without an explicit hook
1210 	 * function.
1211 	 */
1212 	if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1213 	    (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1214 		return false;
1215 
1216 	/*
1217 	 * Ensure that the hook function is compatible with the other
1218 	 * components of the rule
1219 	 */
1220 	switch (entry->func) {
1221 	case NONE:
1222 	case FILE_CHECK:
1223 	case MMAP_CHECK:
1224 	case BPRM_CHECK:
1225 	case CREDS_CHECK:
1226 	case POST_SETATTR:
1227 	case FIRMWARE_CHECK:
1228 	case POLICY_CHECK:
1229 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1230 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1231 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1232 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1233 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1234 				     IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1235 				     IMA_VERITY_REQUIRED))
1236 			return false;
1237 
1238 		break;
1239 	case MODULE_CHECK:
1240 	case KEXEC_KERNEL_CHECK:
1241 	case KEXEC_INITRAMFS_CHECK:
1242 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1243 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1244 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1245 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1246 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1247 				     IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1248 				     IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1249 			return false;
1250 
1251 		break;
1252 	case KEXEC_CMDLINE:
1253 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1254 			return false;
1255 
1256 		if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1257 				     IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1258 				     IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1259 				     IMA_FGROUP))
1260 			return false;
1261 
1262 		break;
1263 	case KEY_CHECK:
1264 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1265 			return false;
1266 
1267 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1268 				     IMA_KEYRINGS))
1269 			return false;
1270 
1271 		if (ima_rule_contains_lsm_cond(entry))
1272 			return false;
1273 
1274 		break;
1275 	case CRITICAL_DATA:
1276 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1277 			return false;
1278 
1279 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1280 				     IMA_LABEL))
1281 			return false;
1282 
1283 		if (ima_rule_contains_lsm_cond(entry))
1284 			return false;
1285 
1286 		break;
1287 	case SETXATTR_CHECK:
1288 		/* any action other than APPRAISE is unsupported */
1289 		if (entry->action != APPRAISE)
1290 			return false;
1291 
1292 		/* SETXATTR_CHECK requires an appraise_algos parameter */
1293 		if (!(entry->flags & IMA_VALIDATE_ALGOS))
1294 			return false;
1295 
1296 		/*
1297 		 * full policies are not supported, they would have too
1298 		 * much of a performance impact
1299 		 */
1300 		if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1301 			return false;
1302 
1303 		break;
1304 	default:
1305 		return false;
1306 	}
1307 
1308 	/* Ensure that combinations of flags are compatible with each other */
1309 	if (entry->flags & IMA_CHECK_BLACKLIST &&
1310 	    !(entry->flags & IMA_MODSIG_ALLOWED))
1311 		return false;
1312 
1313 	/*
1314 	 * Unlike for regular IMA 'appraise' policy rules where security.ima
1315 	 * xattr may contain either a file hash or signature, the security.ima
1316 	 * xattr for fsverity must contain a file signature (sigv3).  Ensure
1317 	 * that 'appraise' rules for fsverity require file signatures by
1318 	 * checking the IMA_DIGSIG_REQUIRED flag is set.
1319 	 */
1320 	if (entry->action == APPRAISE &&
1321 	    (entry->flags & IMA_VERITY_REQUIRED) &&
1322 	    !(entry->flags & IMA_DIGSIG_REQUIRED))
1323 		return false;
1324 
1325 	return true;
1326 }
1327 
1328 static unsigned int ima_parse_appraise_algos(char *arg)
1329 {
1330 	unsigned int res = 0;
1331 	int idx;
1332 	char *token;
1333 
1334 	while ((token = strsep(&arg, ",")) != NULL) {
1335 		idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1336 
1337 		if (idx < 0) {
1338 			pr_err("unknown hash algorithm \"%s\"",
1339 			       token);
1340 			return 0;
1341 		}
1342 
1343 		if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1344 			pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1345 			       token);
1346 			return 0;
1347 		}
1348 
1349 		/* Add the hash algorithm to the 'allowed' bitfield */
1350 		res |= (1U << idx);
1351 	}
1352 
1353 	return res;
1354 }
1355 
1356 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1357 {
1358 	struct audit_buffer *ab;
1359 	char *from;
1360 	char *p;
1361 	bool eid_token; /* either euid or egid */
1362 	struct ima_template_desc *template_desc;
1363 	int result = 0;
1364 
1365 	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1366 				       AUDIT_INTEGRITY_POLICY_RULE);
1367 
1368 	entry->uid = INVALID_UID;
1369 	entry->gid = INVALID_GID;
1370 	entry->fowner = INVALID_UID;
1371 	entry->fgroup = INVALID_GID;
1372 	entry->uid_op = &uid_eq;
1373 	entry->gid_op = &gid_eq;
1374 	entry->fowner_op = &uid_eq;
1375 	entry->fgroup_op = &gid_eq;
1376 	entry->action = UNKNOWN;
1377 	while ((p = strsep(&rule, " \t")) != NULL) {
1378 		substring_t args[MAX_OPT_ARGS];
1379 		int token;
1380 		unsigned long lnum;
1381 
1382 		if (result < 0)
1383 			break;
1384 		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1385 			continue;
1386 		token = match_token(p, policy_tokens, args);
1387 		switch (token) {
1388 		case Opt_measure:
1389 			ima_log_string(ab, "action", "measure");
1390 
1391 			if (entry->action != UNKNOWN)
1392 				result = -EINVAL;
1393 
1394 			entry->action = MEASURE;
1395 			break;
1396 		case Opt_dont_measure:
1397 			ima_log_string(ab, "action", "dont_measure");
1398 
1399 			if (entry->action != UNKNOWN)
1400 				result = -EINVAL;
1401 
1402 			entry->action = DONT_MEASURE;
1403 			break;
1404 		case Opt_appraise:
1405 			ima_log_string(ab, "action", "appraise");
1406 
1407 			if (entry->action != UNKNOWN)
1408 				result = -EINVAL;
1409 
1410 			entry->action = APPRAISE;
1411 			break;
1412 		case Opt_dont_appraise:
1413 			ima_log_string(ab, "action", "dont_appraise");
1414 
1415 			if (entry->action != UNKNOWN)
1416 				result = -EINVAL;
1417 
1418 			entry->action = DONT_APPRAISE;
1419 			break;
1420 		case Opt_audit:
1421 			ima_log_string(ab, "action", "audit");
1422 
1423 			if (entry->action != UNKNOWN)
1424 				result = -EINVAL;
1425 
1426 			entry->action = AUDIT;
1427 			break;
1428 		case Opt_hash:
1429 			ima_log_string(ab, "action", "hash");
1430 
1431 			if (entry->action != UNKNOWN)
1432 				result = -EINVAL;
1433 
1434 			entry->action = HASH;
1435 			break;
1436 		case Opt_dont_hash:
1437 			ima_log_string(ab, "action", "dont_hash");
1438 
1439 			if (entry->action != UNKNOWN)
1440 				result = -EINVAL;
1441 
1442 			entry->action = DONT_HASH;
1443 			break;
1444 		case Opt_func:
1445 			ima_log_string(ab, "func", args[0].from);
1446 
1447 			if (entry->func)
1448 				result = -EINVAL;
1449 
1450 			if (strcmp(args[0].from, "FILE_CHECK") == 0)
1451 				entry->func = FILE_CHECK;
1452 			/* PATH_CHECK is for backwards compat */
1453 			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1454 				entry->func = FILE_CHECK;
1455 			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1456 				entry->func = MODULE_CHECK;
1457 			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1458 				entry->func = FIRMWARE_CHECK;
1459 			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1460 				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
1461 				entry->func = MMAP_CHECK;
1462 			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1463 				entry->func = BPRM_CHECK;
1464 			else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1465 				entry->func = CREDS_CHECK;
1466 			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1467 				 0)
1468 				entry->func = KEXEC_KERNEL_CHECK;
1469 			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1470 				 == 0)
1471 				entry->func = KEXEC_INITRAMFS_CHECK;
1472 			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1473 				entry->func = POLICY_CHECK;
1474 			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1475 				entry->func = KEXEC_CMDLINE;
1476 			else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1477 				 strcmp(args[0].from, "KEY_CHECK") == 0)
1478 				entry->func = KEY_CHECK;
1479 			else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1480 				entry->func = CRITICAL_DATA;
1481 			else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1482 				entry->func = SETXATTR_CHECK;
1483 			else
1484 				result = -EINVAL;
1485 			if (!result)
1486 				entry->flags |= IMA_FUNC;
1487 			break;
1488 		case Opt_mask:
1489 			ima_log_string(ab, "mask", args[0].from);
1490 
1491 			if (entry->mask)
1492 				result = -EINVAL;
1493 
1494 			from = args[0].from;
1495 			if (*from == '^')
1496 				from++;
1497 
1498 			if ((strcmp(from, "MAY_EXEC")) == 0)
1499 				entry->mask = MAY_EXEC;
1500 			else if (strcmp(from, "MAY_WRITE") == 0)
1501 				entry->mask = MAY_WRITE;
1502 			else if (strcmp(from, "MAY_READ") == 0)
1503 				entry->mask = MAY_READ;
1504 			else if (strcmp(from, "MAY_APPEND") == 0)
1505 				entry->mask = MAY_APPEND;
1506 			else
1507 				result = -EINVAL;
1508 			if (!result)
1509 				entry->flags |= (*args[0].from == '^')
1510 				     ? IMA_INMASK : IMA_MASK;
1511 			break;
1512 		case Opt_fsmagic:
1513 			ima_log_string(ab, "fsmagic", args[0].from);
1514 
1515 			if (entry->fsmagic) {
1516 				result = -EINVAL;
1517 				break;
1518 			}
1519 
1520 			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1521 			if (!result)
1522 				entry->flags |= IMA_FSMAGIC;
1523 			break;
1524 		case Opt_fsname:
1525 			ima_log_string(ab, "fsname", args[0].from);
1526 
1527 			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1528 			if (!entry->fsname) {
1529 				result = -ENOMEM;
1530 				break;
1531 			}
1532 			result = 0;
1533 			entry->flags |= IMA_FSNAME;
1534 			break;
1535 		case Opt_keyrings:
1536 			ima_log_string(ab, "keyrings", args[0].from);
1537 
1538 			if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1539 			    entry->keyrings) {
1540 				result = -EINVAL;
1541 				break;
1542 			}
1543 
1544 			entry->keyrings = ima_alloc_rule_opt_list(args);
1545 			if (IS_ERR(entry->keyrings)) {
1546 				result = PTR_ERR(entry->keyrings);
1547 				entry->keyrings = NULL;
1548 				break;
1549 			}
1550 
1551 			entry->flags |= IMA_KEYRINGS;
1552 			break;
1553 		case Opt_label:
1554 			ima_log_string(ab, "label", args[0].from);
1555 
1556 			if (entry->label) {
1557 				result = -EINVAL;
1558 				break;
1559 			}
1560 
1561 			entry->label = ima_alloc_rule_opt_list(args);
1562 			if (IS_ERR(entry->label)) {
1563 				result = PTR_ERR(entry->label);
1564 				entry->label = NULL;
1565 				break;
1566 			}
1567 
1568 			entry->flags |= IMA_LABEL;
1569 			break;
1570 		case Opt_fsuuid:
1571 			ima_log_string(ab, "fsuuid", args[0].from);
1572 
1573 			if (!uuid_is_null(&entry->fsuuid)) {
1574 				result = -EINVAL;
1575 				break;
1576 			}
1577 
1578 			result = uuid_parse(args[0].from, &entry->fsuuid);
1579 			if (!result)
1580 				entry->flags |= IMA_FSUUID;
1581 			break;
1582 		case Opt_uid_gt:
1583 		case Opt_euid_gt:
1584 			entry->uid_op = &uid_gt;
1585 			fallthrough;
1586 		case Opt_uid_lt:
1587 		case Opt_euid_lt:
1588 			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1589 				entry->uid_op = &uid_lt;
1590 			fallthrough;
1591 		case Opt_uid_eq:
1592 		case Opt_euid_eq:
1593 			eid_token = (token == Opt_euid_eq) ||
1594 				    (token == Opt_euid_gt) ||
1595 				    (token == Opt_euid_lt);
1596 
1597 			ima_log_string_op(ab, eid_token ? "euid" : "uid",
1598 					  args[0].from, token);
1599 
1600 			if (uid_valid(entry->uid)) {
1601 				result = -EINVAL;
1602 				break;
1603 			}
1604 
1605 			result = kstrtoul(args[0].from, 10, &lnum);
1606 			if (!result) {
1607 				entry->uid = make_kuid(current_user_ns(),
1608 						       (uid_t) lnum);
1609 				if (!uid_valid(entry->uid) ||
1610 				    (uid_t)lnum != lnum)
1611 					result = -EINVAL;
1612 				else
1613 					entry->flags |= eid_token
1614 					    ? IMA_EUID : IMA_UID;
1615 			}
1616 			break;
1617 		case Opt_gid_gt:
1618 		case Opt_egid_gt:
1619 			entry->gid_op = &gid_gt;
1620 			fallthrough;
1621 		case Opt_gid_lt:
1622 		case Opt_egid_lt:
1623 			if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1624 				entry->gid_op = &gid_lt;
1625 			fallthrough;
1626 		case Opt_gid_eq:
1627 		case Opt_egid_eq:
1628 			eid_token = (token == Opt_egid_eq) ||
1629 				    (token == Opt_egid_gt) ||
1630 				    (token == Opt_egid_lt);
1631 
1632 			ima_log_string_op(ab, eid_token ? "egid" : "gid",
1633 					  args[0].from, token);
1634 
1635 			if (gid_valid(entry->gid)) {
1636 				result = -EINVAL;
1637 				break;
1638 			}
1639 
1640 			result = kstrtoul(args[0].from, 10, &lnum);
1641 			if (!result) {
1642 				entry->gid = make_kgid(current_user_ns(),
1643 						       (gid_t)lnum);
1644 				if (!gid_valid(entry->gid) ||
1645 				    (((gid_t)lnum) != lnum))
1646 					result = -EINVAL;
1647 				else
1648 					entry->flags |= eid_token
1649 					    ? IMA_EGID : IMA_GID;
1650 			}
1651 			break;
1652 		case Opt_fowner_gt:
1653 			entry->fowner_op = &uid_gt;
1654 			fallthrough;
1655 		case Opt_fowner_lt:
1656 			if (token == Opt_fowner_lt)
1657 				entry->fowner_op = &uid_lt;
1658 			fallthrough;
1659 		case Opt_fowner_eq:
1660 			ima_log_string_op(ab, "fowner", args[0].from, token);
1661 
1662 			if (uid_valid(entry->fowner)) {
1663 				result = -EINVAL;
1664 				break;
1665 			}
1666 
1667 			result = kstrtoul(args[0].from, 10, &lnum);
1668 			if (!result) {
1669 				entry->fowner = make_kuid(current_user_ns(),
1670 							  (uid_t)lnum);
1671 				if (!uid_valid(entry->fowner) ||
1672 				    (((uid_t)lnum) != lnum))
1673 					result = -EINVAL;
1674 				else
1675 					entry->flags |= IMA_FOWNER;
1676 			}
1677 			break;
1678 		case Opt_fgroup_gt:
1679 			entry->fgroup_op = &gid_gt;
1680 			fallthrough;
1681 		case Opt_fgroup_lt:
1682 			if (token == Opt_fgroup_lt)
1683 				entry->fgroup_op = &gid_lt;
1684 			fallthrough;
1685 		case Opt_fgroup_eq:
1686 			ima_log_string_op(ab, "fgroup", args[0].from, token);
1687 
1688 			if (gid_valid(entry->fgroup)) {
1689 				result = -EINVAL;
1690 				break;
1691 			}
1692 
1693 			result = kstrtoul(args[0].from, 10, &lnum);
1694 			if (!result) {
1695 				entry->fgroup = make_kgid(current_user_ns(),
1696 							  (gid_t)lnum);
1697 				if (!gid_valid(entry->fgroup) ||
1698 				    (((gid_t)lnum) != lnum))
1699 					result = -EINVAL;
1700 				else
1701 					entry->flags |= IMA_FGROUP;
1702 			}
1703 			break;
1704 		case Opt_obj_user:
1705 			ima_log_string(ab, "obj_user", args[0].from);
1706 			result = ima_lsm_rule_init(entry, args,
1707 						   LSM_OBJ_USER,
1708 						   AUDIT_OBJ_USER);
1709 			break;
1710 		case Opt_obj_role:
1711 			ima_log_string(ab, "obj_role", args[0].from);
1712 			result = ima_lsm_rule_init(entry, args,
1713 						   LSM_OBJ_ROLE,
1714 						   AUDIT_OBJ_ROLE);
1715 			break;
1716 		case Opt_obj_type:
1717 			ima_log_string(ab, "obj_type", args[0].from);
1718 			result = ima_lsm_rule_init(entry, args,
1719 						   LSM_OBJ_TYPE,
1720 						   AUDIT_OBJ_TYPE);
1721 			break;
1722 		case Opt_subj_user:
1723 			ima_log_string(ab, "subj_user", args[0].from);
1724 			result = ima_lsm_rule_init(entry, args,
1725 						   LSM_SUBJ_USER,
1726 						   AUDIT_SUBJ_USER);
1727 			break;
1728 		case Opt_subj_role:
1729 			ima_log_string(ab, "subj_role", args[0].from);
1730 			result = ima_lsm_rule_init(entry, args,
1731 						   LSM_SUBJ_ROLE,
1732 						   AUDIT_SUBJ_ROLE);
1733 			break;
1734 		case Opt_subj_type:
1735 			ima_log_string(ab, "subj_type", args[0].from);
1736 			result = ima_lsm_rule_init(entry, args,
1737 						   LSM_SUBJ_TYPE,
1738 						   AUDIT_SUBJ_TYPE);
1739 			break;
1740 		case Opt_digest_type:
1741 			ima_log_string(ab, "digest_type", args[0].from);
1742 			if (entry->flags & IMA_DIGSIG_REQUIRED)
1743 				result = -EINVAL;
1744 			else if ((strcmp(args[0].from, "verity")) == 0)
1745 				entry->flags |= IMA_VERITY_REQUIRED;
1746 			else
1747 				result = -EINVAL;
1748 			break;
1749 		case Opt_appraise_type:
1750 			ima_log_string(ab, "appraise_type", args[0].from);
1751 
1752 			if ((strcmp(args[0].from, "imasig")) == 0) {
1753 				if (entry->flags & IMA_VERITY_REQUIRED)
1754 					result = -EINVAL;
1755 				else
1756 					entry->flags |= IMA_DIGSIG_REQUIRED;
1757 			} else if (strcmp(args[0].from, "sigv3") == 0) {
1758 				/* Only fsverity supports sigv3 for now */
1759 				if (entry->flags & IMA_VERITY_REQUIRED)
1760 					entry->flags |= IMA_DIGSIG_REQUIRED;
1761 				else
1762 					result = -EINVAL;
1763 			} else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1764 				 strcmp(args[0].from, "imasig|modsig") == 0) {
1765 				if (entry->flags & IMA_VERITY_REQUIRED)
1766 					result = -EINVAL;
1767 				else
1768 					entry->flags |= IMA_DIGSIG_REQUIRED |
1769 						IMA_MODSIG_ALLOWED;
1770 			} else {
1771 				result = -EINVAL;
1772 			}
1773 			break;
1774 		case Opt_appraise_flag:
1775 			ima_log_string(ab, "appraise_flag", args[0].from);
1776 			if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1777 			    strstr(args[0].from, "blacklist"))
1778 				entry->flags |= IMA_CHECK_BLACKLIST;
1779 			else
1780 				result = -EINVAL;
1781 			break;
1782 		case Opt_appraise_algos:
1783 			ima_log_string(ab, "appraise_algos", args[0].from);
1784 
1785 			if (entry->allowed_algos) {
1786 				result = -EINVAL;
1787 				break;
1788 			}
1789 
1790 			entry->allowed_algos =
1791 				ima_parse_appraise_algos(args[0].from);
1792 			/* invalid or empty list of algorithms */
1793 			if (!entry->allowed_algos) {
1794 				result = -EINVAL;
1795 				break;
1796 			}
1797 
1798 			entry->flags |= IMA_VALIDATE_ALGOS;
1799 
1800 			break;
1801 		case Opt_permit_directio:
1802 			entry->flags |= IMA_PERMIT_DIRECTIO;
1803 			break;
1804 		case Opt_pcr:
1805 			ima_log_string(ab, "pcr", args[0].from);
1806 
1807 			result = kstrtoint(args[0].from, 10, &entry->pcr);
1808 			if (result || INVALID_PCR(entry->pcr))
1809 				result = -EINVAL;
1810 			else
1811 				entry->flags |= IMA_PCR;
1812 
1813 			break;
1814 		case Opt_template:
1815 			ima_log_string(ab, "template", args[0].from);
1816 			if (entry->action != MEASURE) {
1817 				result = -EINVAL;
1818 				break;
1819 			}
1820 			template_desc = lookup_template_desc(args[0].from);
1821 			if (!template_desc || entry->template) {
1822 				result = -EINVAL;
1823 				break;
1824 			}
1825 
1826 			/*
1827 			 * template_desc_init_fields() does nothing if
1828 			 * the template is already initialised, so
1829 			 * it's safe to do this unconditionally
1830 			 */
1831 			template_desc_init_fields(template_desc->fmt,
1832 						 &(template_desc->fields),
1833 						 &(template_desc->num_fields));
1834 			entry->template = template_desc;
1835 			break;
1836 		case Opt_err:
1837 			ima_log_string(ab, "UNKNOWN", p);
1838 			result = -EINVAL;
1839 			break;
1840 		}
1841 	}
1842 	if (!result && !ima_validate_rule(entry))
1843 		result = -EINVAL;
1844 	else if (entry->action == APPRAISE)
1845 		temp_ima_appraise |= ima_appraise_flag(entry->func);
1846 
1847 	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1848 		template_desc = entry->template ? entry->template :
1849 						  ima_template_desc_current();
1850 		check_template_modsig(template_desc);
1851 	}
1852 
1853 	/* d-ngv2 template field recommended for unsigned fs-verity digests */
1854 	if (!result && entry->action == MEASURE &&
1855 	    entry->flags & IMA_VERITY_REQUIRED) {
1856 		template_desc = entry->template ? entry->template :
1857 						  ima_template_desc_current();
1858 		check_template_field(template_desc, "d-ngv2",
1859 				     "verity rules should include d-ngv2");
1860 	}
1861 
1862 	audit_log_format(ab, "res=%d", !result);
1863 	audit_log_end(ab);
1864 	return result;
1865 }
1866 
1867 /**
1868  * ima_parse_add_rule - add a rule to ima_policy_rules
1869  * @rule - ima measurement policy rule
1870  *
1871  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1872  * Returns the length of the rule parsed, an error code on failure
1873  */
1874 ssize_t ima_parse_add_rule(char *rule)
1875 {
1876 	static const char op[] = "update_policy";
1877 	char *p;
1878 	struct ima_rule_entry *entry;
1879 	ssize_t result, len;
1880 	int audit_info = 0;
1881 
1882 	p = strsep(&rule, "\n");
1883 	len = strlen(p) + 1;
1884 	p += strspn(p, " \t");
1885 
1886 	if (*p == '#' || *p == '\0')
1887 		return len;
1888 
1889 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1890 	if (!entry) {
1891 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1892 				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1893 		return -ENOMEM;
1894 	}
1895 
1896 	INIT_LIST_HEAD(&entry->list);
1897 
1898 	result = ima_parse_rule(p, entry);
1899 	if (result) {
1900 		ima_free_rule(entry);
1901 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1902 				    NULL, op, "invalid-policy", result,
1903 				    audit_info);
1904 		return result;
1905 	}
1906 
1907 	list_add_tail(&entry->list, &ima_temp_rules);
1908 
1909 	return len;
1910 }
1911 
1912 /**
1913  * ima_delete_rules() called to cleanup invalid in-flight policy.
1914  * We don't need locking as we operate on the temp list, which is
1915  * different from the active one.  There is also only one user of
1916  * ima_delete_rules() at a time.
1917  */
1918 void ima_delete_rules(void)
1919 {
1920 	struct ima_rule_entry *entry, *tmp;
1921 
1922 	temp_ima_appraise = 0;
1923 	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1924 		list_del(&entry->list);
1925 		ima_free_rule(entry);
1926 	}
1927 }
1928 
1929 #define __ima_hook_stringify(func, str)	(#func),
1930 
1931 const char *const func_tokens[] = {
1932 	__ima_hooks(__ima_hook_stringify)
1933 };
1934 
1935 #ifdef	CONFIG_IMA_READ_POLICY
1936 enum {
1937 	mask_exec = 0, mask_write, mask_read, mask_append
1938 };
1939 
1940 static const char *const mask_tokens[] = {
1941 	"^MAY_EXEC",
1942 	"^MAY_WRITE",
1943 	"^MAY_READ",
1944 	"^MAY_APPEND"
1945 };
1946 
1947 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1948 {
1949 	loff_t l = *pos;
1950 	struct ima_rule_entry *entry;
1951 	struct list_head *ima_rules_tmp;
1952 
1953 	rcu_read_lock();
1954 	ima_rules_tmp = rcu_dereference(ima_rules);
1955 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
1956 		if (!l--) {
1957 			rcu_read_unlock();
1958 			return entry;
1959 		}
1960 	}
1961 	rcu_read_unlock();
1962 	return NULL;
1963 }
1964 
1965 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1966 {
1967 	struct ima_rule_entry *entry = v;
1968 
1969 	rcu_read_lock();
1970 	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1971 	rcu_read_unlock();
1972 	(*pos)++;
1973 
1974 	return (&entry->list == &ima_default_rules ||
1975 		&entry->list == &ima_policy_rules) ? NULL : entry;
1976 }
1977 
1978 void ima_policy_stop(struct seq_file *m, void *v)
1979 {
1980 }
1981 
1982 #define pt(token)	policy_tokens[token].pattern
1983 #define mt(token)	mask_tokens[token]
1984 
1985 /*
1986  * policy_func_show - display the ima_hooks policy rule
1987  */
1988 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1989 {
1990 	if (func > 0 && func < MAX_CHECK)
1991 		seq_printf(m, "func=%s ", func_tokens[func]);
1992 	else
1993 		seq_printf(m, "func=%d ", func);
1994 }
1995 
1996 static void ima_show_rule_opt_list(struct seq_file *m,
1997 				   const struct ima_rule_opt_list *opt_list)
1998 {
1999 	size_t i;
2000 
2001 	for (i = 0; i < opt_list->count; i++)
2002 		seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
2003 }
2004 
2005 static void ima_policy_show_appraise_algos(struct seq_file *m,
2006 					   unsigned int allowed_hashes)
2007 {
2008 	int idx, list_size = 0;
2009 
2010 	for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
2011 		if (!(allowed_hashes & (1U << idx)))
2012 			continue;
2013 
2014 		/* only add commas if the list contains multiple entries */
2015 		if (list_size++)
2016 			seq_puts(m, ",");
2017 
2018 		seq_puts(m, hash_algo_name[idx]);
2019 	}
2020 }
2021 
2022 int ima_policy_show(struct seq_file *m, void *v)
2023 {
2024 	struct ima_rule_entry *entry = v;
2025 	int i;
2026 	char tbuf[64] = {0,};
2027 	int offset = 0;
2028 
2029 	rcu_read_lock();
2030 
2031 	/* Do not print rules with inactive LSM labels */
2032 	for (i = 0; i < MAX_LSM_RULES; i++) {
2033 		if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
2034 			rcu_read_unlock();
2035 			return 0;
2036 		}
2037 	}
2038 
2039 	if (entry->action & MEASURE)
2040 		seq_puts(m, pt(Opt_measure));
2041 	if (entry->action & DONT_MEASURE)
2042 		seq_puts(m, pt(Opt_dont_measure));
2043 	if (entry->action & APPRAISE)
2044 		seq_puts(m, pt(Opt_appraise));
2045 	if (entry->action & DONT_APPRAISE)
2046 		seq_puts(m, pt(Opt_dont_appraise));
2047 	if (entry->action & AUDIT)
2048 		seq_puts(m, pt(Opt_audit));
2049 	if (entry->action & HASH)
2050 		seq_puts(m, pt(Opt_hash));
2051 	if (entry->action & DONT_HASH)
2052 		seq_puts(m, pt(Opt_dont_hash));
2053 
2054 	seq_puts(m, " ");
2055 
2056 	if (entry->flags & IMA_FUNC)
2057 		policy_func_show(m, entry->func);
2058 
2059 	if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
2060 		if (entry->flags & IMA_MASK)
2061 			offset = 1;
2062 		if (entry->mask & MAY_EXEC)
2063 			seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2064 		if (entry->mask & MAY_WRITE)
2065 			seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2066 		if (entry->mask & MAY_READ)
2067 			seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2068 		if (entry->mask & MAY_APPEND)
2069 			seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2070 		seq_puts(m, " ");
2071 	}
2072 
2073 	if (entry->flags & IMA_FSMAGIC) {
2074 		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2075 		seq_printf(m, pt(Opt_fsmagic), tbuf);
2076 		seq_puts(m, " ");
2077 	}
2078 
2079 	if (entry->flags & IMA_FSNAME) {
2080 		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2081 		seq_printf(m, pt(Opt_fsname), tbuf);
2082 		seq_puts(m, " ");
2083 	}
2084 
2085 	if (entry->flags & IMA_KEYRINGS) {
2086 		seq_puts(m, "keyrings=");
2087 		ima_show_rule_opt_list(m, entry->keyrings);
2088 		seq_puts(m, " ");
2089 	}
2090 
2091 	if (entry->flags & IMA_LABEL) {
2092 		seq_puts(m, "label=");
2093 		ima_show_rule_opt_list(m, entry->label);
2094 		seq_puts(m, " ");
2095 	}
2096 
2097 	if (entry->flags & IMA_PCR) {
2098 		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2099 		seq_printf(m, pt(Opt_pcr), tbuf);
2100 		seq_puts(m, " ");
2101 	}
2102 
2103 	if (entry->flags & IMA_FSUUID) {
2104 		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2105 		seq_puts(m, " ");
2106 	}
2107 
2108 	if (entry->flags & IMA_UID) {
2109 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2110 		if (entry->uid_op == &uid_gt)
2111 			seq_printf(m, pt(Opt_uid_gt), tbuf);
2112 		else if (entry->uid_op == &uid_lt)
2113 			seq_printf(m, pt(Opt_uid_lt), tbuf);
2114 		else
2115 			seq_printf(m, pt(Opt_uid_eq), tbuf);
2116 		seq_puts(m, " ");
2117 	}
2118 
2119 	if (entry->flags & IMA_EUID) {
2120 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2121 		if (entry->uid_op == &uid_gt)
2122 			seq_printf(m, pt(Opt_euid_gt), tbuf);
2123 		else if (entry->uid_op == &uid_lt)
2124 			seq_printf(m, pt(Opt_euid_lt), tbuf);
2125 		else
2126 			seq_printf(m, pt(Opt_euid_eq), tbuf);
2127 		seq_puts(m, " ");
2128 	}
2129 
2130 	if (entry->flags & IMA_GID) {
2131 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2132 		if (entry->gid_op == &gid_gt)
2133 			seq_printf(m, pt(Opt_gid_gt), tbuf);
2134 		else if (entry->gid_op == &gid_lt)
2135 			seq_printf(m, pt(Opt_gid_lt), tbuf);
2136 		else
2137 			seq_printf(m, pt(Opt_gid_eq), tbuf);
2138 		seq_puts(m, " ");
2139 	}
2140 
2141 	if (entry->flags & IMA_EGID) {
2142 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2143 		if (entry->gid_op == &gid_gt)
2144 			seq_printf(m, pt(Opt_egid_gt), tbuf);
2145 		else if (entry->gid_op == &gid_lt)
2146 			seq_printf(m, pt(Opt_egid_lt), tbuf);
2147 		else
2148 			seq_printf(m, pt(Opt_egid_eq), tbuf);
2149 		seq_puts(m, " ");
2150 	}
2151 
2152 	if (entry->flags & IMA_FOWNER) {
2153 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2154 		if (entry->fowner_op == &uid_gt)
2155 			seq_printf(m, pt(Opt_fowner_gt), tbuf);
2156 		else if (entry->fowner_op == &uid_lt)
2157 			seq_printf(m, pt(Opt_fowner_lt), tbuf);
2158 		else
2159 			seq_printf(m, pt(Opt_fowner_eq), tbuf);
2160 		seq_puts(m, " ");
2161 	}
2162 
2163 	if (entry->flags & IMA_FGROUP) {
2164 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2165 		if (entry->fgroup_op == &gid_gt)
2166 			seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2167 		else if (entry->fgroup_op == &gid_lt)
2168 			seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2169 		else
2170 			seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2171 		seq_puts(m, " ");
2172 	}
2173 
2174 	if (entry->flags & IMA_VALIDATE_ALGOS) {
2175 		seq_puts(m, "appraise_algos=");
2176 		ima_policy_show_appraise_algos(m, entry->allowed_algos);
2177 		seq_puts(m, " ");
2178 	}
2179 
2180 	for (i = 0; i < MAX_LSM_RULES; i++) {
2181 		if (entry->lsm[i].rule) {
2182 			switch (i) {
2183 			case LSM_OBJ_USER:
2184 				seq_printf(m, pt(Opt_obj_user),
2185 					   entry->lsm[i].args_p);
2186 				break;
2187 			case LSM_OBJ_ROLE:
2188 				seq_printf(m, pt(Opt_obj_role),
2189 					   entry->lsm[i].args_p);
2190 				break;
2191 			case LSM_OBJ_TYPE:
2192 				seq_printf(m, pt(Opt_obj_type),
2193 					   entry->lsm[i].args_p);
2194 				break;
2195 			case LSM_SUBJ_USER:
2196 				seq_printf(m, pt(Opt_subj_user),
2197 					   entry->lsm[i].args_p);
2198 				break;
2199 			case LSM_SUBJ_ROLE:
2200 				seq_printf(m, pt(Opt_subj_role),
2201 					   entry->lsm[i].args_p);
2202 				break;
2203 			case LSM_SUBJ_TYPE:
2204 				seq_printf(m, pt(Opt_subj_type),
2205 					   entry->lsm[i].args_p);
2206 				break;
2207 			}
2208 			seq_puts(m, " ");
2209 		}
2210 	}
2211 	if (entry->template)
2212 		seq_printf(m, "template=%s ", entry->template->name);
2213 	if (entry->flags & IMA_DIGSIG_REQUIRED) {
2214 		if (entry->flags & IMA_VERITY_REQUIRED)
2215 			seq_puts(m, "appraise_type=sigv3 ");
2216 		else if (entry->flags & IMA_MODSIG_ALLOWED)
2217 			seq_puts(m, "appraise_type=imasig|modsig ");
2218 		else
2219 			seq_puts(m, "appraise_type=imasig ");
2220 	}
2221 	if (entry->flags & IMA_VERITY_REQUIRED)
2222 		seq_puts(m, "digest_type=verity ");
2223 	if (entry->flags & IMA_CHECK_BLACKLIST)
2224 		seq_puts(m, "appraise_flag=check_blacklist ");
2225 	if (entry->flags & IMA_PERMIT_DIRECTIO)
2226 		seq_puts(m, "permit_directio ");
2227 	rcu_read_unlock();
2228 	seq_puts(m, "\n");
2229 	return 0;
2230 }
2231 #endif	/* CONFIG_IMA_READ_POLICY */
2232 
2233 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2234 /*
2235  * ima_appraise_signature: whether IMA will appraise a given function using
2236  * an IMA digital signature. This is restricted to cases where the kernel
2237  * has a set of built-in trusted keys in order to avoid an attacker simply
2238  * loading additional keys.
2239  */
2240 bool ima_appraise_signature(enum kernel_read_file_id id)
2241 {
2242 	struct ima_rule_entry *entry;
2243 	bool found = false;
2244 	enum ima_hooks func;
2245 	struct list_head *ima_rules_tmp;
2246 
2247 	if (id >= READING_MAX_ID)
2248 		return false;
2249 
2250 	if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2251 	    && security_locked_down(LOCKDOWN_KEXEC))
2252 		return false;
2253 
2254 	func = read_idmap[id] ?: FILE_CHECK;
2255 
2256 	rcu_read_lock();
2257 	ima_rules_tmp = rcu_dereference(ima_rules);
2258 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2259 		if (entry->action != APPRAISE)
2260 			continue;
2261 
2262 		/*
2263 		 * A generic entry will match, but otherwise require that it
2264 		 * match the func we're looking for
2265 		 */
2266 		if (entry->func && entry->func != func)
2267 			continue;
2268 
2269 		/*
2270 		 * We require this to be a digital signature, not a raw IMA
2271 		 * hash.
2272 		 */
2273 		if (entry->flags & IMA_DIGSIG_REQUIRED)
2274 			found = true;
2275 
2276 		/*
2277 		 * We've found a rule that matches, so break now even if it
2278 		 * didn't require a digital signature - a later rule that does
2279 		 * won't override it, so would be a false positive.
2280 		 */
2281 		break;
2282 	}
2283 
2284 	rcu_read_unlock();
2285 	return found;
2286 }
2287 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
2288