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[] __counted_by(count);
72 };
73 
74 /*
75  * These comparators are needed nowhere outside of ima so just define them here.
76  * This pattern should hopefully never be needed outside of ima.
77  */
78 static inline bool vfsuid_gt_kuid(vfsuid_t vfsuid, kuid_t kuid)
79 {
80 	return __vfsuid_val(vfsuid) > __kuid_val(kuid);
81 }
82 
83 static inline bool vfsgid_gt_kgid(vfsgid_t vfsgid, kgid_t kgid)
84 {
85 	return __vfsgid_val(vfsgid) > __kgid_val(kgid);
86 }
87 
88 static inline bool vfsuid_lt_kuid(vfsuid_t vfsuid, kuid_t kuid)
89 {
90 	return __vfsuid_val(vfsuid) < __kuid_val(kuid);
91 }
92 
93 static inline bool vfsgid_lt_kgid(vfsgid_t vfsgid, kgid_t kgid)
94 {
95 	return __vfsgid_val(vfsgid) < __kgid_val(kgid);
96 }
97 
98 struct ima_rule_entry {
99 	struct list_head list;
100 	int action;
101 	unsigned int flags;
102 	enum ima_hooks func;
103 	int mask;
104 	unsigned long fsmagic;
105 	uuid_t fsuuid;
106 	kuid_t uid;
107 	kgid_t gid;
108 	kuid_t fowner;
109 	kgid_t fgroup;
110 	bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
111 	bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
112 	bool (*fowner_op)(vfsuid_t vfsuid, kuid_t rule_uid); /* vfsuid_eq_kuid(), vfsuid_gt_kuid(), vfsuid_lt_kuid() */
113 	bool (*fgroup_op)(vfsgid_t vfsgid, kgid_t rule_gid); /* vfsgid_eq_kgid(), vfsgid_gt_kgid(), vfsgid_lt_kgid() */
114 	int pcr;
115 	unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
116 	struct {
117 		void *rule;	/* LSM file metadata specific */
118 		char *args_p;	/* audit value */
119 		int type;	/* audit type */
120 	} lsm[MAX_LSM_RULES];
121 	char *fsname;
122 	struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
123 	struct ima_rule_opt_list *label; /* Measure data grouped under this label */
124 	struct ima_template_desc *template;
125 };
126 
127 /*
128  * sanity check in case the kernels gains more hash algorithms that can
129  * fit in an unsigned int
130  */
131 static_assert(
132 	8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
133 	"The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
134 
135 /*
136  * Without LSM specific knowledge, the default policy can only be
137  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
138  * .fowner, and .fgroup
139  */
140 
141 /*
142  * The minimum rule set to allow for full TCB coverage.  Measures all files
143  * opened or mmap for exec and everything read by root.  Dangerous because
144  * normal users can easily run the machine out of memory simply building
145  * and running executables.
146  */
147 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
148 	{.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
149 	{.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
150 	{.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
151 	{.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
152 	{.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
153 	{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
154 	{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
155 	{.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
156 	{.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
157 	{.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
158 	 .flags = IMA_FSMAGIC},
159 	{.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
160 	 .flags = IMA_FSMAGIC},
161 	{.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
162 	{.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
163 };
164 
165 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
166 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
167 	 .flags = IMA_FUNC | IMA_MASK},
168 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
169 	 .flags = IMA_FUNC | IMA_MASK},
170 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
171 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
172 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
173 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
174 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
175 };
176 
177 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
178 	{.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
179 	 .flags = IMA_FUNC | IMA_MASK},
180 	{.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
181 	 .flags = IMA_FUNC | IMA_MASK},
182 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
183 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
184 	 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
185 	{.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
186 	 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
187 	 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
188 	{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
189 	{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
190 	{.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
191 };
192 
193 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
194 	{.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
195 	{.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
196 	{.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
197 	{.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
198 	{.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
199 	{.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
200 	{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
201 	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
202 	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
203 	{.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
204 	{.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
205 	{.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
206 	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
207 	{.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
208 #ifdef CONFIG_IMA_WRITE_POLICY
209 	{.action = APPRAISE, .func = POLICY_CHECK,
210 	.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
211 #endif
212 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
213 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
214 	 .flags = IMA_FOWNER},
215 #else
216 	/* force signature */
217 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
218 	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
219 #endif
220 };
221 
222 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
223 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
224 	{.action = APPRAISE, .func = MODULE_CHECK,
225 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
226 #endif
227 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
228 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
229 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
230 #endif
231 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
232 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
233 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
234 #endif
235 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
236 	{.action = APPRAISE, .func = POLICY_CHECK,
237 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
238 #endif
239 };
240 
241 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
242 	{.action = APPRAISE, .func = MODULE_CHECK,
243 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
244 	{.action = APPRAISE, .func = FIRMWARE_CHECK,
245 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
246 	{.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
247 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
248 	{.action = APPRAISE, .func = POLICY_CHECK,
249 	 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
250 };
251 
252 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
253 	{.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
254 };
255 
256 /* An array of architecture specific rules */
257 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
258 
259 static LIST_HEAD(ima_default_rules);
260 static LIST_HEAD(ima_policy_rules);
261 static LIST_HEAD(ima_temp_rules);
262 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
263 
264 static int ima_policy __initdata;
265 
266 static int __init default_measure_policy_setup(char *str)
267 {
268 	if (ima_policy)
269 		return 1;
270 
271 	ima_policy = ORIGINAL_TCB;
272 	return 1;
273 }
274 __setup("ima_tcb", default_measure_policy_setup);
275 
276 static bool ima_use_appraise_tcb __initdata;
277 static bool ima_use_secure_boot __initdata;
278 static bool ima_use_critical_data __initdata;
279 static bool ima_fail_unverifiable_sigs __ro_after_init;
280 static int __init policy_setup(char *str)
281 {
282 	char *p;
283 
284 	while ((p = strsep(&str, " |\n")) != NULL) {
285 		if (*p == ' ')
286 			continue;
287 		if ((strcmp(p, "tcb") == 0) && !ima_policy)
288 			ima_policy = DEFAULT_TCB;
289 		else if (strcmp(p, "appraise_tcb") == 0)
290 			ima_use_appraise_tcb = true;
291 		else if (strcmp(p, "secure_boot") == 0)
292 			ima_use_secure_boot = true;
293 		else if (strcmp(p, "critical_data") == 0)
294 			ima_use_critical_data = true;
295 		else if (strcmp(p, "fail_securely") == 0)
296 			ima_fail_unverifiable_sigs = true;
297 		else
298 			pr_err("policy \"%s\" not found", p);
299 	}
300 
301 	return 1;
302 }
303 __setup("ima_policy=", policy_setup);
304 
305 static int __init default_appraise_policy_setup(char *str)
306 {
307 	ima_use_appraise_tcb = true;
308 	return 1;
309 }
310 __setup("ima_appraise_tcb", default_appraise_policy_setup);
311 
312 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
313 {
314 	struct ima_rule_opt_list *opt_list;
315 	size_t count = 0;
316 	char *src_copy;
317 	char *cur, *next;
318 	size_t i;
319 
320 	src_copy = match_strdup(src);
321 	if (!src_copy)
322 		return ERR_PTR(-ENOMEM);
323 
324 	next = src_copy;
325 	while ((cur = strsep(&next, "|"))) {
326 		/* Don't accept an empty list item */
327 		if (!(*cur)) {
328 			kfree(src_copy);
329 			return ERR_PTR(-EINVAL);
330 		}
331 		count++;
332 	}
333 
334 	/* Don't accept an empty list */
335 	if (!count) {
336 		kfree(src_copy);
337 		return ERR_PTR(-EINVAL);
338 	}
339 
340 	opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
341 	if (!opt_list) {
342 		kfree(src_copy);
343 		return ERR_PTR(-ENOMEM);
344 	}
345 	opt_list->count = count;
346 
347 	/*
348 	 * strsep() has already replaced all instances of '|' with '\0',
349 	 * leaving a byte sequence of NUL-terminated strings. Reference each
350 	 * string with the array of items.
351 	 *
352 	 * IMPORTANT: Ownership of the allocated buffer is transferred from
353 	 * src_copy to the first element in the items array. To free the
354 	 * buffer, kfree() must only be called on the first element of the
355 	 * array.
356 	 */
357 	for (i = 0, cur = src_copy; i < count; i++) {
358 		opt_list->items[i] = cur;
359 		cur = strchr(cur, '\0') + 1;
360 	}
361 
362 	return opt_list;
363 }
364 
365 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
366 {
367 	if (!opt_list)
368 		return;
369 
370 	if (opt_list->count) {
371 		kfree(opt_list->items[0]);
372 		opt_list->count = 0;
373 	}
374 
375 	kfree(opt_list);
376 }
377 
378 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
379 {
380 	int i;
381 
382 	for (i = 0; i < MAX_LSM_RULES; i++) {
383 		ima_filter_rule_free(entry->lsm[i].rule);
384 		kfree(entry->lsm[i].args_p);
385 	}
386 }
387 
388 static void ima_free_rule(struct ima_rule_entry *entry)
389 {
390 	if (!entry)
391 		return;
392 
393 	/*
394 	 * entry->template->fields may be allocated in ima_parse_rule() but that
395 	 * reference is owned by the corresponding ima_template_desc element in
396 	 * the defined_templates list and cannot be freed here
397 	 */
398 	kfree(entry->fsname);
399 	ima_free_rule_opt_list(entry->keyrings);
400 	ima_lsm_free_rule(entry);
401 	kfree(entry);
402 }
403 
404 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
405 {
406 	struct ima_rule_entry *nentry;
407 	int i;
408 
409 	/*
410 	 * Immutable elements are copied over as pointers and data; only
411 	 * lsm rules can change
412 	 */
413 	nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
414 	if (!nentry)
415 		return NULL;
416 
417 	memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
418 
419 	for (i = 0; i < MAX_LSM_RULES; i++) {
420 		if (!entry->lsm[i].args_p)
421 			continue;
422 
423 		nentry->lsm[i].type = entry->lsm[i].type;
424 		nentry->lsm[i].args_p = entry->lsm[i].args_p;
425 
426 		ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
427 				     nentry->lsm[i].args_p,
428 				     &nentry->lsm[i].rule);
429 		if (!nentry->lsm[i].rule)
430 			pr_warn("rule for LSM \'%s\' is undefined\n",
431 				nentry->lsm[i].args_p);
432 	}
433 	return nentry;
434 }
435 
436 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
437 {
438 	int i;
439 	struct ima_rule_entry *nentry;
440 
441 	nentry = ima_lsm_copy_rule(entry);
442 	if (!nentry)
443 		return -ENOMEM;
444 
445 	list_replace_rcu(&entry->list, &nentry->list);
446 	synchronize_rcu();
447 	/*
448 	 * ima_lsm_copy_rule() shallow copied all references, except for the
449 	 * LSM references, from entry to nentry so we only want to free the LSM
450 	 * references and the entry itself. All other memory references will now
451 	 * be owned by nentry.
452 	 */
453 	for (i = 0; i < MAX_LSM_RULES; i++)
454 		ima_filter_rule_free(entry->lsm[i].rule);
455 	kfree(entry);
456 
457 	return 0;
458 }
459 
460 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
461 {
462 	int i;
463 
464 	for (i = 0; i < MAX_LSM_RULES; i++)
465 		if (entry->lsm[i].args_p)
466 			return true;
467 
468 	return false;
469 }
470 
471 /*
472  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
473  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
474  * the reloaded LSM policy.
475  */
476 static void ima_lsm_update_rules(void)
477 {
478 	struct ima_rule_entry *entry, *e;
479 	int result;
480 
481 	list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
482 		if (!ima_rule_contains_lsm_cond(entry))
483 			continue;
484 
485 		result = ima_lsm_update_rule(entry);
486 		if (result) {
487 			pr_err("lsm rule update error %d\n", result);
488 			return;
489 		}
490 	}
491 }
492 
493 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
494 			  void *lsm_data)
495 {
496 	if (event != LSM_POLICY_CHANGE)
497 		return NOTIFY_DONE;
498 
499 	ima_lsm_update_rules();
500 	return NOTIFY_OK;
501 }
502 
503 /**
504  * ima_match_rule_data - determine whether func_data matches the policy rule
505  * @rule: a pointer to a rule
506  * @func_data: data to match against the measure rule data
507  * @cred: a pointer to a credentials structure for user validation
508  *
509  * Returns true if func_data matches one in the rule, false otherwise.
510  */
511 static bool ima_match_rule_data(struct ima_rule_entry *rule,
512 				const char *func_data,
513 				const struct cred *cred)
514 {
515 	const struct ima_rule_opt_list *opt_list = NULL;
516 	bool matched = false;
517 	size_t i;
518 
519 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
520 		return false;
521 
522 	switch (rule->func) {
523 	case KEY_CHECK:
524 		if (!rule->keyrings)
525 			return true;
526 
527 		opt_list = rule->keyrings;
528 		break;
529 	case CRITICAL_DATA:
530 		if (!rule->label)
531 			return true;
532 
533 		opt_list = rule->label;
534 		break;
535 	default:
536 		return false;
537 	}
538 
539 	if (!func_data)
540 		return false;
541 
542 	for (i = 0; i < opt_list->count; i++) {
543 		if (!strcmp(opt_list->items[i], func_data)) {
544 			matched = true;
545 			break;
546 		}
547 	}
548 
549 	return matched;
550 }
551 
552 /**
553  * ima_match_rules - determine whether an inode matches the policy rule.
554  * @rule: a pointer to a rule
555  * @idmap: idmap of the mount the inode was found from
556  * @inode: a pointer to an inode
557  * @cred: a pointer to a credentials structure for user validation
558  * @secid: the secid of the task to be validated
559  * @func: LIM hook identifier
560  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
561  * @func_data: func specific data, may be NULL
562  *
563  * Returns true on rule match, false on failure.
564  */
565 static bool ima_match_rules(struct ima_rule_entry *rule,
566 			    struct mnt_idmap *idmap,
567 			    struct inode *inode, const struct cred *cred,
568 			    u32 secid, enum ima_hooks func, int mask,
569 			    const char *func_data)
570 {
571 	int i;
572 	bool result = false;
573 	struct ima_rule_entry *lsm_rule = rule;
574 	bool rule_reinitialized = false;
575 
576 	if ((rule->flags & IMA_FUNC) &&
577 	    (rule->func != func && func != POST_SETATTR))
578 		return false;
579 
580 	switch (func) {
581 	case KEY_CHECK:
582 	case CRITICAL_DATA:
583 		return ((rule->func == func) &&
584 			ima_match_rule_data(rule, func_data, cred));
585 	default:
586 		break;
587 	}
588 
589 	if ((rule->flags & IMA_MASK) &&
590 	    (rule->mask != mask && func != POST_SETATTR))
591 		return false;
592 	if ((rule->flags & IMA_INMASK) &&
593 	    (!(rule->mask & mask) && func != POST_SETATTR))
594 		return false;
595 	if ((rule->flags & IMA_FSMAGIC)
596 	    && rule->fsmagic != inode->i_sb->s_magic)
597 		return false;
598 	if ((rule->flags & IMA_FSNAME)
599 	    && strcmp(rule->fsname, inode->i_sb->s_type->name))
600 		return false;
601 	if ((rule->flags & IMA_FSUUID) &&
602 	    !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
603 		return false;
604 	if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
605 		return false;
606 	if (rule->flags & IMA_EUID) {
607 		if (has_capability_noaudit(current, CAP_SETUID)) {
608 			if (!rule->uid_op(cred->euid, rule->uid)
609 			    && !rule->uid_op(cred->suid, rule->uid)
610 			    && !rule->uid_op(cred->uid, rule->uid))
611 				return false;
612 		} else if (!rule->uid_op(cred->euid, rule->uid))
613 			return false;
614 	}
615 	if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
616 		return false;
617 	if (rule->flags & IMA_EGID) {
618 		if (has_capability_noaudit(current, CAP_SETGID)) {
619 			if (!rule->gid_op(cred->egid, rule->gid)
620 			    && !rule->gid_op(cred->sgid, rule->gid)
621 			    && !rule->gid_op(cred->gid, rule->gid))
622 				return false;
623 		} else if (!rule->gid_op(cred->egid, rule->gid))
624 			return false;
625 	}
626 	if ((rule->flags & IMA_FOWNER) &&
627 	    !rule->fowner_op(i_uid_into_vfsuid(idmap, inode),
628 			     rule->fowner))
629 		return false;
630 	if ((rule->flags & IMA_FGROUP) &&
631 	    !rule->fgroup_op(i_gid_into_vfsgid(idmap, inode),
632 			     rule->fgroup))
633 		return false;
634 	for (i = 0; i < MAX_LSM_RULES; i++) {
635 		int rc = 0;
636 		u32 osid;
637 
638 		if (!lsm_rule->lsm[i].rule) {
639 			if (!lsm_rule->lsm[i].args_p)
640 				continue;
641 			else
642 				return false;
643 		}
644 
645 retry:
646 		switch (i) {
647 		case LSM_OBJ_USER:
648 		case LSM_OBJ_ROLE:
649 		case LSM_OBJ_TYPE:
650 			security_inode_getsecid(inode, &osid);
651 			rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
652 						   Audit_equal,
653 						   lsm_rule->lsm[i].rule);
654 			break;
655 		case LSM_SUBJ_USER:
656 		case LSM_SUBJ_ROLE:
657 		case LSM_SUBJ_TYPE:
658 			rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
659 						   Audit_equal,
660 						   lsm_rule->lsm[i].rule);
661 			break;
662 		default:
663 			break;
664 		}
665 
666 		if (rc == -ESTALE && !rule_reinitialized) {
667 			lsm_rule = ima_lsm_copy_rule(rule);
668 			if (lsm_rule) {
669 				rule_reinitialized = true;
670 				goto retry;
671 			}
672 		}
673 		if (!rc) {
674 			result = false;
675 			goto out;
676 		}
677 	}
678 	result = true;
679 
680 out:
681 	if (rule_reinitialized) {
682 		for (i = 0; i < MAX_LSM_RULES; i++)
683 			ima_filter_rule_free(lsm_rule->lsm[i].rule);
684 		kfree(lsm_rule);
685 	}
686 	return result;
687 }
688 
689 /*
690  * In addition to knowing that we need to appraise the file in general,
691  * we need to differentiate between calling hooks, for hook specific rules.
692  */
693 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
694 {
695 	if (!(rule->flags & IMA_FUNC))
696 		return IMA_FILE_APPRAISE;
697 
698 	switch (func) {
699 	case MMAP_CHECK:
700 	case MMAP_CHECK_REQPROT:
701 		return IMA_MMAP_APPRAISE;
702 	case BPRM_CHECK:
703 		return IMA_BPRM_APPRAISE;
704 	case CREDS_CHECK:
705 		return IMA_CREDS_APPRAISE;
706 	case FILE_CHECK:
707 	case POST_SETATTR:
708 		return IMA_FILE_APPRAISE;
709 	case MODULE_CHECK ... MAX_CHECK - 1:
710 	default:
711 		return IMA_READ_APPRAISE;
712 	}
713 }
714 
715 /**
716  * ima_match_policy - decision based on LSM and other conditions
717  * @idmap: idmap of the mount the inode was found from
718  * @inode: pointer to an inode for which the policy decision is being made
719  * @cred: pointer to a credentials structure for which the policy decision is
720  *        being made
721  * @secid: LSM secid of the task to be validated
722  * @func: IMA hook identifier
723  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
724  * @flags: IMA actions to consider (e.g. IMA_MEASURE | IMA_APPRAISE)
725  * @pcr: set the pcr to extend
726  * @template_desc: the template that should be used for this rule
727  * @func_data: func specific data, may be NULL
728  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
729  *
730  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
731  * conditions.
732  *
733  * Since the IMA policy may be updated multiple times we need to lock the
734  * list when walking it.  Reads are many orders of magnitude more numerous
735  * than writes so ima_match_policy() is classical RCU candidate.
736  */
737 int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
738 		     const struct cred *cred, u32 secid, enum ima_hooks func,
739 		     int mask, int flags, int *pcr,
740 		     struct ima_template_desc **template_desc,
741 		     const char *func_data, unsigned int *allowed_algos)
742 {
743 	struct ima_rule_entry *entry;
744 	int action = 0, actmask = flags | (flags << 1);
745 	struct list_head *ima_rules_tmp;
746 
747 	if (template_desc && !*template_desc)
748 		*template_desc = ima_template_desc_current();
749 
750 	rcu_read_lock();
751 	ima_rules_tmp = rcu_dereference(ima_rules);
752 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
753 
754 		if (!(entry->action & actmask))
755 			continue;
756 
757 		if (!ima_match_rules(entry, idmap, inode, cred, secid,
758 				     func, mask, func_data))
759 			continue;
760 
761 		action |= entry->flags & IMA_NONACTION_FLAGS;
762 
763 		action |= entry->action & IMA_DO_MASK;
764 		if (entry->action & IMA_APPRAISE) {
765 			action |= get_subaction(entry, func);
766 			action &= ~IMA_HASH;
767 			if (ima_fail_unverifiable_sigs)
768 				action |= IMA_FAIL_UNVERIFIABLE_SIGS;
769 
770 			if (allowed_algos &&
771 			    entry->flags & IMA_VALIDATE_ALGOS)
772 				*allowed_algos = entry->allowed_algos;
773 		}
774 
775 		if (entry->action & IMA_DO_MASK)
776 			actmask &= ~(entry->action | entry->action << 1);
777 		else
778 			actmask &= ~(entry->action | entry->action >> 1);
779 
780 		if ((pcr) && (entry->flags & IMA_PCR))
781 			*pcr = entry->pcr;
782 
783 		if (template_desc && entry->template)
784 			*template_desc = entry->template;
785 
786 		if (!actmask)
787 			break;
788 	}
789 	rcu_read_unlock();
790 
791 	return action;
792 }
793 
794 /**
795  * ima_update_policy_flags() - Update global IMA variables
796  *
797  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
798  * based on the currently loaded policy.
799  *
800  * With ima_policy_flag, the decision to short circuit out of a function
801  * or not call the function in the first place can be made earlier.
802  *
803  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
804  * set of hash algorithms accepted when updating the security.ima xattr of
805  * a file.
806  *
807  * Context: called after a policy update and at system initialization.
808  */
809 void ima_update_policy_flags(void)
810 {
811 	struct ima_rule_entry *entry;
812 	int new_policy_flag = 0;
813 	struct list_head *ima_rules_tmp;
814 
815 	rcu_read_lock();
816 	ima_rules_tmp = rcu_dereference(ima_rules);
817 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
818 		/*
819 		 * SETXATTR_CHECK rules do not implement a full policy check
820 		 * because rule checking would probably have an important
821 		 * performance impact on setxattr(). As a consequence, only one
822 		 * SETXATTR_CHECK can be active at a given time.
823 		 * Because we want to preserve that property, we set out to use
824 		 * atomic_cmpxchg. Either:
825 		 * - the atomic was non-zero: a setxattr hash policy is
826 		 *   already enforced, we do nothing
827 		 * - the atomic was zero: no setxattr policy was set, enable
828 		 *   the setxattr hash policy
829 		 */
830 		if (entry->func == SETXATTR_CHECK) {
831 			atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
832 				       0, entry->allowed_algos);
833 			/* SETXATTR_CHECK doesn't impact ima_policy_flag */
834 			continue;
835 		}
836 
837 		if (entry->action & IMA_DO_MASK)
838 			new_policy_flag |= entry->action;
839 	}
840 	rcu_read_unlock();
841 
842 	ima_appraise |= (build_ima_appraise | temp_ima_appraise);
843 	if (!ima_appraise)
844 		new_policy_flag &= ~IMA_APPRAISE;
845 
846 	ima_policy_flag = new_policy_flag;
847 }
848 
849 static int ima_appraise_flag(enum ima_hooks func)
850 {
851 	if (func == MODULE_CHECK)
852 		return IMA_APPRAISE_MODULES;
853 	else if (func == FIRMWARE_CHECK)
854 		return IMA_APPRAISE_FIRMWARE;
855 	else if (func == POLICY_CHECK)
856 		return IMA_APPRAISE_POLICY;
857 	else if (func == KEXEC_KERNEL_CHECK)
858 		return IMA_APPRAISE_KEXEC;
859 	return 0;
860 }
861 
862 static void add_rules(struct ima_rule_entry *entries, int count,
863 		      enum policy_rule_list policy_rule)
864 {
865 	int i = 0;
866 
867 	for (i = 0; i < count; i++) {
868 		struct ima_rule_entry *entry;
869 
870 		if (policy_rule & IMA_DEFAULT_POLICY)
871 			list_add_tail(&entries[i].list, &ima_default_rules);
872 
873 		if (policy_rule & IMA_CUSTOM_POLICY) {
874 			entry = kmemdup(&entries[i], sizeof(*entry),
875 					GFP_KERNEL);
876 			if (!entry)
877 				continue;
878 
879 			list_add_tail(&entry->list, &ima_policy_rules);
880 		}
881 		if (entries[i].action == APPRAISE) {
882 			if (entries != build_appraise_rules)
883 				temp_ima_appraise |=
884 					ima_appraise_flag(entries[i].func);
885 			else
886 				build_ima_appraise |=
887 					ima_appraise_flag(entries[i].func);
888 		}
889 	}
890 }
891 
892 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
893 
894 static int __init ima_init_arch_policy(void)
895 {
896 	const char * const *arch_rules;
897 	const char * const *rules;
898 	int arch_entries = 0;
899 	int i = 0;
900 
901 	arch_rules = arch_get_ima_policy();
902 	if (!arch_rules)
903 		return arch_entries;
904 
905 	/* Get number of rules */
906 	for (rules = arch_rules; *rules != NULL; rules++)
907 		arch_entries++;
908 
909 	arch_policy_entry = kcalloc(arch_entries + 1,
910 				    sizeof(*arch_policy_entry), GFP_KERNEL);
911 	if (!arch_policy_entry)
912 		return 0;
913 
914 	/* Convert each policy string rules to struct ima_rule_entry format */
915 	for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
916 		char rule[255];
917 		int result;
918 
919 		result = strscpy(rule, *rules, sizeof(rule));
920 
921 		INIT_LIST_HEAD(&arch_policy_entry[i].list);
922 		result = ima_parse_rule(rule, &arch_policy_entry[i]);
923 		if (result) {
924 			pr_warn("Skipping unknown architecture policy rule: %s\n",
925 				rule);
926 			memset(&arch_policy_entry[i], 0,
927 			       sizeof(*arch_policy_entry));
928 			continue;
929 		}
930 		i++;
931 	}
932 	return i;
933 }
934 
935 /**
936  * ima_init_policy - initialize the default measure rules.
937  *
938  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
939  */
940 void __init ima_init_policy(void)
941 {
942 	int build_appraise_entries, arch_entries;
943 
944 	/* if !ima_policy, we load NO default rules */
945 	if (ima_policy)
946 		add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
947 			  IMA_DEFAULT_POLICY);
948 
949 	switch (ima_policy) {
950 	case ORIGINAL_TCB:
951 		add_rules(original_measurement_rules,
952 			  ARRAY_SIZE(original_measurement_rules),
953 			  IMA_DEFAULT_POLICY);
954 		break;
955 	case DEFAULT_TCB:
956 		add_rules(default_measurement_rules,
957 			  ARRAY_SIZE(default_measurement_rules),
958 			  IMA_DEFAULT_POLICY);
959 		break;
960 	default:
961 		break;
962 	}
963 
964 	/*
965 	 * Based on runtime secure boot flags, insert arch specific measurement
966 	 * and appraise rules requiring file signatures for both the initial
967 	 * and custom policies, prior to other appraise rules.
968 	 * (Highest priority)
969 	 */
970 	arch_entries = ima_init_arch_policy();
971 	if (!arch_entries)
972 		pr_info("No architecture policies found\n");
973 	else
974 		add_rules(arch_policy_entry, arch_entries,
975 			  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
976 
977 	/*
978 	 * Insert the builtin "secure_boot" policy rules requiring file
979 	 * signatures, prior to other appraise rules.
980 	 */
981 	if (ima_use_secure_boot)
982 		add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
983 			  IMA_DEFAULT_POLICY);
984 
985 	/*
986 	 * Insert the build time appraise rules requiring file signatures
987 	 * for both the initial and custom policies, prior to other appraise
988 	 * rules. As the secure boot rules includes all of the build time
989 	 * rules, include either one or the other set of rules, but not both.
990 	 */
991 	build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
992 	if (build_appraise_entries) {
993 		if (ima_use_secure_boot)
994 			add_rules(build_appraise_rules, build_appraise_entries,
995 				  IMA_CUSTOM_POLICY);
996 		else
997 			add_rules(build_appraise_rules, build_appraise_entries,
998 				  IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
999 	}
1000 
1001 	if (ima_use_appraise_tcb)
1002 		add_rules(default_appraise_rules,
1003 			  ARRAY_SIZE(default_appraise_rules),
1004 			  IMA_DEFAULT_POLICY);
1005 
1006 	if (ima_use_critical_data)
1007 		add_rules(critical_data_rules,
1008 			  ARRAY_SIZE(critical_data_rules),
1009 			  IMA_DEFAULT_POLICY);
1010 
1011 	atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
1012 
1013 	ima_update_policy_flags();
1014 }
1015 
1016 /* Make sure we have a valid policy, at least containing some rules. */
1017 int ima_check_policy(void)
1018 {
1019 	if (list_empty(&ima_temp_rules))
1020 		return -EINVAL;
1021 	return 0;
1022 }
1023 
1024 /**
1025  * ima_update_policy - update default_rules with new measure rules
1026  *
1027  * Called on file .release to update the default rules with a complete new
1028  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
1029  * they make a queue.  The policy may be updated multiple times and this is the
1030  * RCU updater.
1031  *
1032  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
1033  * we switch from the default policy to user defined.
1034  */
1035 void ima_update_policy(void)
1036 {
1037 	struct list_head *policy = &ima_policy_rules;
1038 
1039 	list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
1040 
1041 	if (ima_rules != (struct list_head __rcu *)policy) {
1042 		ima_policy_flag = 0;
1043 
1044 		rcu_assign_pointer(ima_rules, policy);
1045 		/*
1046 		 * IMA architecture specific policy rules are specified
1047 		 * as strings and converted to an array of ima_entry_rules
1048 		 * on boot.  After loading a custom policy, free the
1049 		 * architecture specific rules stored as an array.
1050 		 */
1051 		kfree(arch_policy_entry);
1052 	}
1053 	ima_update_policy_flags();
1054 
1055 	/* Custom IMA policy has been loaded */
1056 	ima_process_queued_keys();
1057 }
1058 
1059 /* Keep the enumeration in sync with the policy_tokens! */
1060 enum policy_opt {
1061 	Opt_measure, Opt_dont_measure,
1062 	Opt_appraise, Opt_dont_appraise,
1063 	Opt_audit, Opt_hash, Opt_dont_hash,
1064 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
1065 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
1066 	Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1067 	Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1068 	Opt_fowner_eq, Opt_fgroup_eq,
1069 	Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1070 	Opt_fowner_gt, Opt_fgroup_gt,
1071 	Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1072 	Opt_fowner_lt, Opt_fgroup_lt,
1073 	Opt_digest_type,
1074 	Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1075 	Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1076 	Opt_label, Opt_err
1077 };
1078 
1079 static const match_table_t policy_tokens = {
1080 	{Opt_measure, "measure"},
1081 	{Opt_dont_measure, "dont_measure"},
1082 	{Opt_appraise, "appraise"},
1083 	{Opt_dont_appraise, "dont_appraise"},
1084 	{Opt_audit, "audit"},
1085 	{Opt_hash, "hash"},
1086 	{Opt_dont_hash, "dont_hash"},
1087 	{Opt_obj_user, "obj_user=%s"},
1088 	{Opt_obj_role, "obj_role=%s"},
1089 	{Opt_obj_type, "obj_type=%s"},
1090 	{Opt_subj_user, "subj_user=%s"},
1091 	{Opt_subj_role, "subj_role=%s"},
1092 	{Opt_subj_type, "subj_type=%s"},
1093 	{Opt_func, "func=%s"},
1094 	{Opt_mask, "mask=%s"},
1095 	{Opt_fsmagic, "fsmagic=%s"},
1096 	{Opt_fsname, "fsname=%s"},
1097 	{Opt_fsuuid, "fsuuid=%s"},
1098 	{Opt_uid_eq, "uid=%s"},
1099 	{Opt_euid_eq, "euid=%s"},
1100 	{Opt_gid_eq, "gid=%s"},
1101 	{Opt_egid_eq, "egid=%s"},
1102 	{Opt_fowner_eq, "fowner=%s"},
1103 	{Opt_fgroup_eq, "fgroup=%s"},
1104 	{Opt_uid_gt, "uid>%s"},
1105 	{Opt_euid_gt, "euid>%s"},
1106 	{Opt_gid_gt, "gid>%s"},
1107 	{Opt_egid_gt, "egid>%s"},
1108 	{Opt_fowner_gt, "fowner>%s"},
1109 	{Opt_fgroup_gt, "fgroup>%s"},
1110 	{Opt_uid_lt, "uid<%s"},
1111 	{Opt_euid_lt, "euid<%s"},
1112 	{Opt_gid_lt, "gid<%s"},
1113 	{Opt_egid_lt, "egid<%s"},
1114 	{Opt_fowner_lt, "fowner<%s"},
1115 	{Opt_fgroup_lt, "fgroup<%s"},
1116 	{Opt_digest_type, "digest_type=%s"},
1117 	{Opt_appraise_type, "appraise_type=%s"},
1118 	{Opt_appraise_flag, "appraise_flag=%s"},
1119 	{Opt_appraise_algos, "appraise_algos=%s"},
1120 	{Opt_permit_directio, "permit_directio"},
1121 	{Opt_pcr, "pcr=%s"},
1122 	{Opt_template, "template=%s"},
1123 	{Opt_keyrings, "keyrings=%s"},
1124 	{Opt_label, "label=%s"},
1125 	{Opt_err, NULL}
1126 };
1127 
1128 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1129 			     substring_t *args, int lsm_rule, int audit_type)
1130 {
1131 	int result;
1132 
1133 	if (entry->lsm[lsm_rule].rule)
1134 		return -EINVAL;
1135 
1136 	entry->lsm[lsm_rule].args_p = match_strdup(args);
1137 	if (!entry->lsm[lsm_rule].args_p)
1138 		return -ENOMEM;
1139 
1140 	entry->lsm[lsm_rule].type = audit_type;
1141 	result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1142 				      entry->lsm[lsm_rule].args_p,
1143 				      &entry->lsm[lsm_rule].rule);
1144 	if (!entry->lsm[lsm_rule].rule) {
1145 		pr_warn("rule for LSM \'%s\' is undefined\n",
1146 			entry->lsm[lsm_rule].args_p);
1147 
1148 		if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1149 			kfree(entry->lsm[lsm_rule].args_p);
1150 			entry->lsm[lsm_rule].args_p = NULL;
1151 			result = -EINVAL;
1152 		} else
1153 			result = 0;
1154 	}
1155 
1156 	return result;
1157 }
1158 
1159 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1160 			      enum policy_opt rule_operator)
1161 {
1162 	if (!ab)
1163 		return;
1164 
1165 	switch (rule_operator) {
1166 	case Opt_uid_gt:
1167 	case Opt_euid_gt:
1168 	case Opt_gid_gt:
1169 	case Opt_egid_gt:
1170 	case Opt_fowner_gt:
1171 	case Opt_fgroup_gt:
1172 		audit_log_format(ab, "%s>", key);
1173 		break;
1174 	case Opt_uid_lt:
1175 	case Opt_euid_lt:
1176 	case Opt_gid_lt:
1177 	case Opt_egid_lt:
1178 	case Opt_fowner_lt:
1179 	case Opt_fgroup_lt:
1180 		audit_log_format(ab, "%s<", key);
1181 		break;
1182 	default:
1183 		audit_log_format(ab, "%s=", key);
1184 	}
1185 	audit_log_format(ab, "%s ", value);
1186 }
1187 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1188 {
1189 	ima_log_string_op(ab, key, value, Opt_err);
1190 }
1191 
1192 /*
1193  * Validating the appended signature included in the measurement list requires
1194  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1195  * field). Therefore, notify the user if they have the 'modsig' field but not
1196  * the 'd-modsig' field in the template.
1197  */
1198 static void check_template_modsig(const struct ima_template_desc *template)
1199 {
1200 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1201 	bool has_modsig, has_dmodsig;
1202 	static bool checked;
1203 	int i;
1204 
1205 	/* We only need to notify the user once. */
1206 	if (checked)
1207 		return;
1208 
1209 	has_modsig = has_dmodsig = false;
1210 	for (i = 0; i < template->num_fields; i++) {
1211 		if (!strcmp(template->fields[i]->field_id, "modsig"))
1212 			has_modsig = true;
1213 		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1214 			has_dmodsig = true;
1215 	}
1216 
1217 	if (has_modsig && !has_dmodsig)
1218 		pr_notice(MSG);
1219 
1220 	checked = true;
1221 #undef MSG
1222 }
1223 
1224 /*
1225  * Warn if the template does not contain the given field.
1226  */
1227 static void check_template_field(const struct ima_template_desc *template,
1228 				 const char *field, const char *msg)
1229 {
1230 	int i;
1231 
1232 	for (i = 0; i < template->num_fields; i++)
1233 		if (!strcmp(template->fields[i]->field_id, field))
1234 			return;
1235 
1236 	pr_notice_once("%s", msg);
1237 }
1238 
1239 static bool ima_validate_rule(struct ima_rule_entry *entry)
1240 {
1241 	/* Ensure that the action is set and is compatible with the flags */
1242 	if (entry->action == UNKNOWN)
1243 		return false;
1244 
1245 	if (entry->action != MEASURE && entry->flags & IMA_PCR)
1246 		return false;
1247 
1248 	if (entry->action != APPRAISE &&
1249 	    entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1250 			    IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1251 		return false;
1252 
1253 	/*
1254 	 * The IMA_FUNC bit must be set if and only if there's a valid hook
1255 	 * function specified, and vice versa. Enforcing this property allows
1256 	 * for the NONE case below to validate a rule without an explicit hook
1257 	 * function.
1258 	 */
1259 	if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1260 	    (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1261 		return false;
1262 
1263 	/*
1264 	 * Ensure that the hook function is compatible with the other
1265 	 * components of the rule
1266 	 */
1267 	switch (entry->func) {
1268 	case NONE:
1269 	case FILE_CHECK:
1270 	case MMAP_CHECK:
1271 	case MMAP_CHECK_REQPROT:
1272 	case BPRM_CHECK:
1273 	case CREDS_CHECK:
1274 	case POST_SETATTR:
1275 	case FIRMWARE_CHECK:
1276 	case POLICY_CHECK:
1277 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1278 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1279 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1280 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1281 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1282 				     IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1283 				     IMA_CHECK_BLACKLIST | IMA_VERITY_REQUIRED))
1284 			return false;
1285 
1286 		break;
1287 	case MODULE_CHECK:
1288 	case KEXEC_KERNEL_CHECK:
1289 	case KEXEC_INITRAMFS_CHECK:
1290 		if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1291 				     IMA_UID | IMA_FOWNER | IMA_FSUUID |
1292 				     IMA_INMASK | IMA_EUID | IMA_PCR |
1293 				     IMA_FSNAME | IMA_GID | IMA_EGID |
1294 				     IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1295 				     IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1296 				     IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1297 			return false;
1298 
1299 		break;
1300 	case KEXEC_CMDLINE:
1301 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1302 			return false;
1303 
1304 		if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1305 				     IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1306 				     IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1307 				     IMA_FGROUP))
1308 			return false;
1309 
1310 		break;
1311 	case KEY_CHECK:
1312 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1313 			return false;
1314 
1315 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1316 				     IMA_KEYRINGS))
1317 			return false;
1318 
1319 		if (ima_rule_contains_lsm_cond(entry))
1320 			return false;
1321 
1322 		break;
1323 	case CRITICAL_DATA:
1324 		if (entry->action & ~(MEASURE | DONT_MEASURE))
1325 			return false;
1326 
1327 		if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1328 				     IMA_LABEL))
1329 			return false;
1330 
1331 		if (ima_rule_contains_lsm_cond(entry))
1332 			return false;
1333 
1334 		break;
1335 	case SETXATTR_CHECK:
1336 		/* any action other than APPRAISE is unsupported */
1337 		if (entry->action != APPRAISE)
1338 			return false;
1339 
1340 		/* SETXATTR_CHECK requires an appraise_algos parameter */
1341 		if (!(entry->flags & IMA_VALIDATE_ALGOS))
1342 			return false;
1343 
1344 		/*
1345 		 * full policies are not supported, they would have too
1346 		 * much of a performance impact
1347 		 */
1348 		if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1349 			return false;
1350 
1351 		break;
1352 	default:
1353 		return false;
1354 	}
1355 
1356 	/* Ensure that combinations of flags are compatible with each other */
1357 	if (entry->flags & IMA_CHECK_BLACKLIST &&
1358 	    !(entry->flags & IMA_DIGSIG_REQUIRED))
1359 		return false;
1360 
1361 	/*
1362 	 * Unlike for regular IMA 'appraise' policy rules where security.ima
1363 	 * xattr may contain either a file hash or signature, the security.ima
1364 	 * xattr for fsverity must contain a file signature (sigv3).  Ensure
1365 	 * that 'appraise' rules for fsverity require file signatures by
1366 	 * checking the IMA_DIGSIG_REQUIRED flag is set.
1367 	 */
1368 	if (entry->action == APPRAISE &&
1369 	    (entry->flags & IMA_VERITY_REQUIRED) &&
1370 	    !(entry->flags & IMA_DIGSIG_REQUIRED))
1371 		return false;
1372 
1373 	return true;
1374 }
1375 
1376 static unsigned int ima_parse_appraise_algos(char *arg)
1377 {
1378 	unsigned int res = 0;
1379 	int idx;
1380 	char *token;
1381 
1382 	while ((token = strsep(&arg, ",")) != NULL) {
1383 		idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1384 
1385 		if (idx < 0) {
1386 			pr_err("unknown hash algorithm \"%s\"",
1387 			       token);
1388 			return 0;
1389 		}
1390 
1391 		if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1392 			pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1393 			       token);
1394 			return 0;
1395 		}
1396 
1397 		/* Add the hash algorithm to the 'allowed' bitfield */
1398 		res |= (1U << idx);
1399 	}
1400 
1401 	return res;
1402 }
1403 
1404 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1405 {
1406 	struct audit_buffer *ab;
1407 	char *from;
1408 	char *p;
1409 	bool eid_token; /* either euid or egid */
1410 	struct ima_template_desc *template_desc;
1411 	int result = 0;
1412 
1413 	ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1414 				       AUDIT_INTEGRITY_POLICY_RULE);
1415 
1416 	entry->uid = INVALID_UID;
1417 	entry->gid = INVALID_GID;
1418 	entry->fowner = INVALID_UID;
1419 	entry->fgroup = INVALID_GID;
1420 	entry->uid_op = &uid_eq;
1421 	entry->gid_op = &gid_eq;
1422 	entry->fowner_op = &vfsuid_eq_kuid;
1423 	entry->fgroup_op = &vfsgid_eq_kgid;
1424 	entry->action = UNKNOWN;
1425 	while ((p = strsep(&rule, " \t")) != NULL) {
1426 		substring_t args[MAX_OPT_ARGS];
1427 		int token;
1428 		unsigned long lnum;
1429 
1430 		if (result < 0)
1431 			break;
1432 		if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1433 			continue;
1434 		token = match_token(p, policy_tokens, args);
1435 		switch (token) {
1436 		case Opt_measure:
1437 			ima_log_string(ab, "action", "measure");
1438 
1439 			if (entry->action != UNKNOWN)
1440 				result = -EINVAL;
1441 
1442 			entry->action = MEASURE;
1443 			break;
1444 		case Opt_dont_measure:
1445 			ima_log_string(ab, "action", "dont_measure");
1446 
1447 			if (entry->action != UNKNOWN)
1448 				result = -EINVAL;
1449 
1450 			entry->action = DONT_MEASURE;
1451 			break;
1452 		case Opt_appraise:
1453 			ima_log_string(ab, "action", "appraise");
1454 
1455 			if (entry->action != UNKNOWN)
1456 				result = -EINVAL;
1457 
1458 			entry->action = APPRAISE;
1459 			break;
1460 		case Opt_dont_appraise:
1461 			ima_log_string(ab, "action", "dont_appraise");
1462 
1463 			if (entry->action != UNKNOWN)
1464 				result = -EINVAL;
1465 
1466 			entry->action = DONT_APPRAISE;
1467 			break;
1468 		case Opt_audit:
1469 			ima_log_string(ab, "action", "audit");
1470 
1471 			if (entry->action != UNKNOWN)
1472 				result = -EINVAL;
1473 
1474 			entry->action = AUDIT;
1475 			break;
1476 		case Opt_hash:
1477 			ima_log_string(ab, "action", "hash");
1478 
1479 			if (entry->action != UNKNOWN)
1480 				result = -EINVAL;
1481 
1482 			entry->action = HASH;
1483 			break;
1484 		case Opt_dont_hash:
1485 			ima_log_string(ab, "action", "dont_hash");
1486 
1487 			if (entry->action != UNKNOWN)
1488 				result = -EINVAL;
1489 
1490 			entry->action = DONT_HASH;
1491 			break;
1492 		case Opt_func:
1493 			ima_log_string(ab, "func", args[0].from);
1494 
1495 			if (entry->func)
1496 				result = -EINVAL;
1497 
1498 			if (strcmp(args[0].from, "FILE_CHECK") == 0)
1499 				entry->func = FILE_CHECK;
1500 			/* PATH_CHECK is for backwards compat */
1501 			else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1502 				entry->func = FILE_CHECK;
1503 			else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1504 				entry->func = MODULE_CHECK;
1505 			else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1506 				entry->func = FIRMWARE_CHECK;
1507 			else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1508 				|| (strcmp(args[0].from, "MMAP_CHECK") == 0))
1509 				entry->func = MMAP_CHECK;
1510 			else if ((strcmp(args[0].from, "MMAP_CHECK_REQPROT") == 0))
1511 				entry->func = MMAP_CHECK_REQPROT;
1512 			else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1513 				entry->func = BPRM_CHECK;
1514 			else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1515 				entry->func = CREDS_CHECK;
1516 			else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1517 				 0)
1518 				entry->func = KEXEC_KERNEL_CHECK;
1519 			else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1520 				 == 0)
1521 				entry->func = KEXEC_INITRAMFS_CHECK;
1522 			else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1523 				entry->func = POLICY_CHECK;
1524 			else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1525 				entry->func = KEXEC_CMDLINE;
1526 			else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1527 				 strcmp(args[0].from, "KEY_CHECK") == 0)
1528 				entry->func = KEY_CHECK;
1529 			else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1530 				entry->func = CRITICAL_DATA;
1531 			else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1532 				entry->func = SETXATTR_CHECK;
1533 			else
1534 				result = -EINVAL;
1535 			if (!result)
1536 				entry->flags |= IMA_FUNC;
1537 			break;
1538 		case Opt_mask:
1539 			ima_log_string(ab, "mask", args[0].from);
1540 
1541 			if (entry->mask)
1542 				result = -EINVAL;
1543 
1544 			from = args[0].from;
1545 			if (*from == '^')
1546 				from++;
1547 
1548 			if ((strcmp(from, "MAY_EXEC")) == 0)
1549 				entry->mask = MAY_EXEC;
1550 			else if (strcmp(from, "MAY_WRITE") == 0)
1551 				entry->mask = MAY_WRITE;
1552 			else if (strcmp(from, "MAY_READ") == 0)
1553 				entry->mask = MAY_READ;
1554 			else if (strcmp(from, "MAY_APPEND") == 0)
1555 				entry->mask = MAY_APPEND;
1556 			else
1557 				result = -EINVAL;
1558 			if (!result)
1559 				entry->flags |= (*args[0].from == '^')
1560 				     ? IMA_INMASK : IMA_MASK;
1561 			break;
1562 		case Opt_fsmagic:
1563 			ima_log_string(ab, "fsmagic", args[0].from);
1564 
1565 			if (entry->fsmagic) {
1566 				result = -EINVAL;
1567 				break;
1568 			}
1569 
1570 			result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1571 			if (!result)
1572 				entry->flags |= IMA_FSMAGIC;
1573 			break;
1574 		case Opt_fsname:
1575 			ima_log_string(ab, "fsname", args[0].from);
1576 
1577 			entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1578 			if (!entry->fsname) {
1579 				result = -ENOMEM;
1580 				break;
1581 			}
1582 			result = 0;
1583 			entry->flags |= IMA_FSNAME;
1584 			break;
1585 		case Opt_keyrings:
1586 			ima_log_string(ab, "keyrings", args[0].from);
1587 
1588 			if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1589 			    entry->keyrings) {
1590 				result = -EINVAL;
1591 				break;
1592 			}
1593 
1594 			entry->keyrings = ima_alloc_rule_opt_list(args);
1595 			if (IS_ERR(entry->keyrings)) {
1596 				result = PTR_ERR(entry->keyrings);
1597 				entry->keyrings = NULL;
1598 				break;
1599 			}
1600 
1601 			entry->flags |= IMA_KEYRINGS;
1602 			break;
1603 		case Opt_label:
1604 			ima_log_string(ab, "label", args[0].from);
1605 
1606 			if (entry->label) {
1607 				result = -EINVAL;
1608 				break;
1609 			}
1610 
1611 			entry->label = ima_alloc_rule_opt_list(args);
1612 			if (IS_ERR(entry->label)) {
1613 				result = PTR_ERR(entry->label);
1614 				entry->label = NULL;
1615 				break;
1616 			}
1617 
1618 			entry->flags |= IMA_LABEL;
1619 			break;
1620 		case Opt_fsuuid:
1621 			ima_log_string(ab, "fsuuid", args[0].from);
1622 
1623 			if (!uuid_is_null(&entry->fsuuid)) {
1624 				result = -EINVAL;
1625 				break;
1626 			}
1627 
1628 			result = uuid_parse(args[0].from, &entry->fsuuid);
1629 			if (!result)
1630 				entry->flags |= IMA_FSUUID;
1631 			break;
1632 		case Opt_uid_gt:
1633 		case Opt_euid_gt:
1634 			entry->uid_op = &uid_gt;
1635 			fallthrough;
1636 		case Opt_uid_lt:
1637 		case Opt_euid_lt:
1638 			if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1639 				entry->uid_op = &uid_lt;
1640 			fallthrough;
1641 		case Opt_uid_eq:
1642 		case Opt_euid_eq:
1643 			eid_token = (token == Opt_euid_eq) ||
1644 				    (token == Opt_euid_gt) ||
1645 				    (token == Opt_euid_lt);
1646 
1647 			ima_log_string_op(ab, eid_token ? "euid" : "uid",
1648 					  args[0].from, token);
1649 
1650 			if (uid_valid(entry->uid)) {
1651 				result = -EINVAL;
1652 				break;
1653 			}
1654 
1655 			result = kstrtoul(args[0].from, 10, &lnum);
1656 			if (!result) {
1657 				entry->uid = make_kuid(current_user_ns(),
1658 						       (uid_t) lnum);
1659 				if (!uid_valid(entry->uid) ||
1660 				    (uid_t)lnum != lnum)
1661 					result = -EINVAL;
1662 				else
1663 					entry->flags |= eid_token
1664 					    ? IMA_EUID : IMA_UID;
1665 			}
1666 			break;
1667 		case Opt_gid_gt:
1668 		case Opt_egid_gt:
1669 			entry->gid_op = &gid_gt;
1670 			fallthrough;
1671 		case Opt_gid_lt:
1672 		case Opt_egid_lt:
1673 			if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1674 				entry->gid_op = &gid_lt;
1675 			fallthrough;
1676 		case Opt_gid_eq:
1677 		case Opt_egid_eq:
1678 			eid_token = (token == Opt_egid_eq) ||
1679 				    (token == Opt_egid_gt) ||
1680 				    (token == Opt_egid_lt);
1681 
1682 			ima_log_string_op(ab, eid_token ? "egid" : "gid",
1683 					  args[0].from, token);
1684 
1685 			if (gid_valid(entry->gid)) {
1686 				result = -EINVAL;
1687 				break;
1688 			}
1689 
1690 			result = kstrtoul(args[0].from, 10, &lnum);
1691 			if (!result) {
1692 				entry->gid = make_kgid(current_user_ns(),
1693 						       (gid_t)lnum);
1694 				if (!gid_valid(entry->gid) ||
1695 				    (((gid_t)lnum) != lnum))
1696 					result = -EINVAL;
1697 				else
1698 					entry->flags |= eid_token
1699 					    ? IMA_EGID : IMA_GID;
1700 			}
1701 			break;
1702 		case Opt_fowner_gt:
1703 			entry->fowner_op = &vfsuid_gt_kuid;
1704 			fallthrough;
1705 		case Opt_fowner_lt:
1706 			if (token == Opt_fowner_lt)
1707 				entry->fowner_op = &vfsuid_lt_kuid;
1708 			fallthrough;
1709 		case Opt_fowner_eq:
1710 			ima_log_string_op(ab, "fowner", args[0].from, token);
1711 
1712 			if (uid_valid(entry->fowner)) {
1713 				result = -EINVAL;
1714 				break;
1715 			}
1716 
1717 			result = kstrtoul(args[0].from, 10, &lnum);
1718 			if (!result) {
1719 				entry->fowner = make_kuid(current_user_ns(),
1720 							  (uid_t)lnum);
1721 				if (!uid_valid(entry->fowner) ||
1722 				    (((uid_t)lnum) != lnum))
1723 					result = -EINVAL;
1724 				else
1725 					entry->flags |= IMA_FOWNER;
1726 			}
1727 			break;
1728 		case Opt_fgroup_gt:
1729 			entry->fgroup_op = &vfsgid_gt_kgid;
1730 			fallthrough;
1731 		case Opt_fgroup_lt:
1732 			if (token == Opt_fgroup_lt)
1733 				entry->fgroup_op = &vfsgid_lt_kgid;
1734 			fallthrough;
1735 		case Opt_fgroup_eq:
1736 			ima_log_string_op(ab, "fgroup", args[0].from, token);
1737 
1738 			if (gid_valid(entry->fgroup)) {
1739 				result = -EINVAL;
1740 				break;
1741 			}
1742 
1743 			result = kstrtoul(args[0].from, 10, &lnum);
1744 			if (!result) {
1745 				entry->fgroup = make_kgid(current_user_ns(),
1746 							  (gid_t)lnum);
1747 				if (!gid_valid(entry->fgroup) ||
1748 				    (((gid_t)lnum) != lnum))
1749 					result = -EINVAL;
1750 				else
1751 					entry->flags |= IMA_FGROUP;
1752 			}
1753 			break;
1754 		case Opt_obj_user:
1755 			ima_log_string(ab, "obj_user", args[0].from);
1756 			result = ima_lsm_rule_init(entry, args,
1757 						   LSM_OBJ_USER,
1758 						   AUDIT_OBJ_USER);
1759 			break;
1760 		case Opt_obj_role:
1761 			ima_log_string(ab, "obj_role", args[0].from);
1762 			result = ima_lsm_rule_init(entry, args,
1763 						   LSM_OBJ_ROLE,
1764 						   AUDIT_OBJ_ROLE);
1765 			break;
1766 		case Opt_obj_type:
1767 			ima_log_string(ab, "obj_type", args[0].from);
1768 			result = ima_lsm_rule_init(entry, args,
1769 						   LSM_OBJ_TYPE,
1770 						   AUDIT_OBJ_TYPE);
1771 			break;
1772 		case Opt_subj_user:
1773 			ima_log_string(ab, "subj_user", args[0].from);
1774 			result = ima_lsm_rule_init(entry, args,
1775 						   LSM_SUBJ_USER,
1776 						   AUDIT_SUBJ_USER);
1777 			break;
1778 		case Opt_subj_role:
1779 			ima_log_string(ab, "subj_role", args[0].from);
1780 			result = ima_lsm_rule_init(entry, args,
1781 						   LSM_SUBJ_ROLE,
1782 						   AUDIT_SUBJ_ROLE);
1783 			break;
1784 		case Opt_subj_type:
1785 			ima_log_string(ab, "subj_type", args[0].from);
1786 			result = ima_lsm_rule_init(entry, args,
1787 						   LSM_SUBJ_TYPE,
1788 						   AUDIT_SUBJ_TYPE);
1789 			break;
1790 		case Opt_digest_type:
1791 			ima_log_string(ab, "digest_type", args[0].from);
1792 			if (entry->flags & IMA_DIGSIG_REQUIRED)
1793 				result = -EINVAL;
1794 			else if ((strcmp(args[0].from, "verity")) == 0)
1795 				entry->flags |= IMA_VERITY_REQUIRED;
1796 			else
1797 				result = -EINVAL;
1798 			break;
1799 		case Opt_appraise_type:
1800 			ima_log_string(ab, "appraise_type", args[0].from);
1801 
1802 			if ((strcmp(args[0].from, "imasig")) == 0) {
1803 				if (entry->flags & IMA_VERITY_REQUIRED)
1804 					result = -EINVAL;
1805 				else
1806 					entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
1807 			} else if (strcmp(args[0].from, "sigv3") == 0) {
1808 				/* Only fsverity supports sigv3 for now */
1809 				if (entry->flags & IMA_VERITY_REQUIRED)
1810 					entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
1811 				else
1812 					result = -EINVAL;
1813 			} else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1814 				 strcmp(args[0].from, "imasig|modsig") == 0) {
1815 				if (entry->flags & IMA_VERITY_REQUIRED)
1816 					result = -EINVAL;
1817 				else
1818 					entry->flags |= IMA_DIGSIG_REQUIRED |
1819 						IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST;
1820 			} else {
1821 				result = -EINVAL;
1822 			}
1823 			break;
1824 		case Opt_appraise_flag:
1825 			ima_log_string(ab, "appraise_flag", args[0].from);
1826 			break;
1827 		case Opt_appraise_algos:
1828 			ima_log_string(ab, "appraise_algos", args[0].from);
1829 
1830 			if (entry->allowed_algos) {
1831 				result = -EINVAL;
1832 				break;
1833 			}
1834 
1835 			entry->allowed_algos =
1836 				ima_parse_appraise_algos(args[0].from);
1837 			/* invalid or empty list of algorithms */
1838 			if (!entry->allowed_algos) {
1839 				result = -EINVAL;
1840 				break;
1841 			}
1842 
1843 			entry->flags |= IMA_VALIDATE_ALGOS;
1844 
1845 			break;
1846 		case Opt_permit_directio:
1847 			entry->flags |= IMA_PERMIT_DIRECTIO;
1848 			break;
1849 		case Opt_pcr:
1850 			ima_log_string(ab, "pcr", args[0].from);
1851 
1852 			result = kstrtoint(args[0].from, 10, &entry->pcr);
1853 			if (result || INVALID_PCR(entry->pcr))
1854 				result = -EINVAL;
1855 			else
1856 				entry->flags |= IMA_PCR;
1857 
1858 			break;
1859 		case Opt_template:
1860 			ima_log_string(ab, "template", args[0].from);
1861 			if (entry->action != MEASURE) {
1862 				result = -EINVAL;
1863 				break;
1864 			}
1865 			template_desc = lookup_template_desc(args[0].from);
1866 			if (!template_desc || entry->template) {
1867 				result = -EINVAL;
1868 				break;
1869 			}
1870 
1871 			/*
1872 			 * template_desc_init_fields() does nothing if
1873 			 * the template is already initialised, so
1874 			 * it's safe to do this unconditionally
1875 			 */
1876 			template_desc_init_fields(template_desc->fmt,
1877 						 &(template_desc->fields),
1878 						 &(template_desc->num_fields));
1879 			entry->template = template_desc;
1880 			break;
1881 		case Opt_err:
1882 			ima_log_string(ab, "UNKNOWN", p);
1883 			result = -EINVAL;
1884 			break;
1885 		}
1886 	}
1887 	if (!result && !ima_validate_rule(entry))
1888 		result = -EINVAL;
1889 	else if (entry->action == APPRAISE)
1890 		temp_ima_appraise |= ima_appraise_flag(entry->func);
1891 
1892 	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1893 		template_desc = entry->template ? entry->template :
1894 						  ima_template_desc_current();
1895 		check_template_modsig(template_desc);
1896 	}
1897 
1898 	/* d-ngv2 template field recommended for unsigned fs-verity digests */
1899 	if (!result && entry->action == MEASURE &&
1900 	    entry->flags & IMA_VERITY_REQUIRED) {
1901 		template_desc = entry->template ? entry->template :
1902 						  ima_template_desc_current();
1903 		check_template_field(template_desc, "d-ngv2",
1904 				     "verity rules should include d-ngv2");
1905 	}
1906 
1907 	audit_log_format(ab, "res=%d", !result);
1908 	audit_log_end(ab);
1909 	return result;
1910 }
1911 
1912 /**
1913  * ima_parse_add_rule - add a rule to ima_policy_rules
1914  * @rule: ima measurement policy rule
1915  *
1916  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1917  * Returns the length of the rule parsed, an error code on failure
1918  */
1919 ssize_t ima_parse_add_rule(char *rule)
1920 {
1921 	static const char op[] = "update_policy";
1922 	char *p;
1923 	struct ima_rule_entry *entry;
1924 	ssize_t result, len;
1925 	int audit_info = 0;
1926 
1927 	p = strsep(&rule, "\n");
1928 	len = strlen(p) + 1;
1929 	p += strspn(p, " \t");
1930 
1931 	if (*p == '#' || *p == '\0')
1932 		return len;
1933 
1934 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1935 	if (!entry) {
1936 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1937 				    NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1938 		return -ENOMEM;
1939 	}
1940 
1941 	INIT_LIST_HEAD(&entry->list);
1942 
1943 	result = ima_parse_rule(p, entry);
1944 	if (result) {
1945 		ima_free_rule(entry);
1946 		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1947 				    NULL, op, "invalid-policy", result,
1948 				    audit_info);
1949 		return result;
1950 	}
1951 
1952 	list_add_tail(&entry->list, &ima_temp_rules);
1953 
1954 	return len;
1955 }
1956 
1957 /**
1958  * ima_delete_rules() - called to cleanup invalid in-flight policy.
1959  *
1960  * We don't need locking as we operate on the temp list, which is
1961  * different from the active one.  There is also only one user of
1962  * ima_delete_rules() at a time.
1963  */
1964 void ima_delete_rules(void)
1965 {
1966 	struct ima_rule_entry *entry, *tmp;
1967 
1968 	temp_ima_appraise = 0;
1969 	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1970 		list_del(&entry->list);
1971 		ima_free_rule(entry);
1972 	}
1973 }
1974 
1975 #define __ima_hook_stringify(func, str)	(#func),
1976 
1977 const char *const func_tokens[] = {
1978 	__ima_hooks(__ima_hook_stringify)
1979 };
1980 
1981 #ifdef	CONFIG_IMA_READ_POLICY
1982 enum {
1983 	mask_exec = 0, mask_write, mask_read, mask_append
1984 };
1985 
1986 static const char *const mask_tokens[] = {
1987 	"^MAY_EXEC",
1988 	"^MAY_WRITE",
1989 	"^MAY_READ",
1990 	"^MAY_APPEND"
1991 };
1992 
1993 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1994 {
1995 	loff_t l = *pos;
1996 	struct ima_rule_entry *entry;
1997 	struct list_head *ima_rules_tmp;
1998 
1999 	rcu_read_lock();
2000 	ima_rules_tmp = rcu_dereference(ima_rules);
2001 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2002 		if (!l--) {
2003 			rcu_read_unlock();
2004 			return entry;
2005 		}
2006 	}
2007 	rcu_read_unlock();
2008 	return NULL;
2009 }
2010 
2011 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
2012 {
2013 	struct ima_rule_entry *entry = v;
2014 
2015 	rcu_read_lock();
2016 	entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
2017 	rcu_read_unlock();
2018 	(*pos)++;
2019 
2020 	return (&entry->list == &ima_default_rules ||
2021 		&entry->list == &ima_policy_rules) ? NULL : entry;
2022 }
2023 
2024 void ima_policy_stop(struct seq_file *m, void *v)
2025 {
2026 }
2027 
2028 #define pt(token)	policy_tokens[token].pattern
2029 #define mt(token)	mask_tokens[token]
2030 
2031 /*
2032  * policy_func_show - display the ima_hooks policy rule
2033  */
2034 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
2035 {
2036 	if (func > 0 && func < MAX_CHECK)
2037 		seq_printf(m, "func=%s ", func_tokens[func]);
2038 	else
2039 		seq_printf(m, "func=%d ", func);
2040 }
2041 
2042 static void ima_show_rule_opt_list(struct seq_file *m,
2043 				   const struct ima_rule_opt_list *opt_list)
2044 {
2045 	size_t i;
2046 
2047 	for (i = 0; i < opt_list->count; i++)
2048 		seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
2049 }
2050 
2051 static void ima_policy_show_appraise_algos(struct seq_file *m,
2052 					   unsigned int allowed_hashes)
2053 {
2054 	int idx, list_size = 0;
2055 
2056 	for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
2057 		if (!(allowed_hashes & (1U << idx)))
2058 			continue;
2059 
2060 		/* only add commas if the list contains multiple entries */
2061 		if (list_size++)
2062 			seq_puts(m, ",");
2063 
2064 		seq_puts(m, hash_algo_name[idx]);
2065 	}
2066 }
2067 
2068 int ima_policy_show(struct seq_file *m, void *v)
2069 {
2070 	struct ima_rule_entry *entry = v;
2071 	int i;
2072 	char tbuf[64] = {0,};
2073 	int offset = 0;
2074 
2075 	rcu_read_lock();
2076 
2077 	/* Do not print rules with inactive LSM labels */
2078 	for (i = 0; i < MAX_LSM_RULES; i++) {
2079 		if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
2080 			rcu_read_unlock();
2081 			return 0;
2082 		}
2083 	}
2084 
2085 	if (entry->action & MEASURE)
2086 		seq_puts(m, pt(Opt_measure));
2087 	if (entry->action & DONT_MEASURE)
2088 		seq_puts(m, pt(Opt_dont_measure));
2089 	if (entry->action & APPRAISE)
2090 		seq_puts(m, pt(Opt_appraise));
2091 	if (entry->action & DONT_APPRAISE)
2092 		seq_puts(m, pt(Opt_dont_appraise));
2093 	if (entry->action & AUDIT)
2094 		seq_puts(m, pt(Opt_audit));
2095 	if (entry->action & HASH)
2096 		seq_puts(m, pt(Opt_hash));
2097 	if (entry->action & DONT_HASH)
2098 		seq_puts(m, pt(Opt_dont_hash));
2099 
2100 	seq_puts(m, " ");
2101 
2102 	if (entry->flags & IMA_FUNC)
2103 		policy_func_show(m, entry->func);
2104 
2105 	if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
2106 		if (entry->flags & IMA_MASK)
2107 			offset = 1;
2108 		if (entry->mask & MAY_EXEC)
2109 			seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2110 		if (entry->mask & MAY_WRITE)
2111 			seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2112 		if (entry->mask & MAY_READ)
2113 			seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2114 		if (entry->mask & MAY_APPEND)
2115 			seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2116 		seq_puts(m, " ");
2117 	}
2118 
2119 	if (entry->flags & IMA_FSMAGIC) {
2120 		snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2121 		seq_printf(m, pt(Opt_fsmagic), tbuf);
2122 		seq_puts(m, " ");
2123 	}
2124 
2125 	if (entry->flags & IMA_FSNAME) {
2126 		snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2127 		seq_printf(m, pt(Opt_fsname), tbuf);
2128 		seq_puts(m, " ");
2129 	}
2130 
2131 	if (entry->flags & IMA_KEYRINGS) {
2132 		seq_puts(m, "keyrings=");
2133 		ima_show_rule_opt_list(m, entry->keyrings);
2134 		seq_puts(m, " ");
2135 	}
2136 
2137 	if (entry->flags & IMA_LABEL) {
2138 		seq_puts(m, "label=");
2139 		ima_show_rule_opt_list(m, entry->label);
2140 		seq_puts(m, " ");
2141 	}
2142 
2143 	if (entry->flags & IMA_PCR) {
2144 		snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2145 		seq_printf(m, pt(Opt_pcr), tbuf);
2146 		seq_puts(m, " ");
2147 	}
2148 
2149 	if (entry->flags & IMA_FSUUID) {
2150 		seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2151 		seq_puts(m, " ");
2152 	}
2153 
2154 	if (entry->flags & IMA_UID) {
2155 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2156 		if (entry->uid_op == &uid_gt)
2157 			seq_printf(m, pt(Opt_uid_gt), tbuf);
2158 		else if (entry->uid_op == &uid_lt)
2159 			seq_printf(m, pt(Opt_uid_lt), tbuf);
2160 		else
2161 			seq_printf(m, pt(Opt_uid_eq), tbuf);
2162 		seq_puts(m, " ");
2163 	}
2164 
2165 	if (entry->flags & IMA_EUID) {
2166 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2167 		if (entry->uid_op == &uid_gt)
2168 			seq_printf(m, pt(Opt_euid_gt), tbuf);
2169 		else if (entry->uid_op == &uid_lt)
2170 			seq_printf(m, pt(Opt_euid_lt), tbuf);
2171 		else
2172 			seq_printf(m, pt(Opt_euid_eq), tbuf);
2173 		seq_puts(m, " ");
2174 	}
2175 
2176 	if (entry->flags & IMA_GID) {
2177 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2178 		if (entry->gid_op == &gid_gt)
2179 			seq_printf(m, pt(Opt_gid_gt), tbuf);
2180 		else if (entry->gid_op == &gid_lt)
2181 			seq_printf(m, pt(Opt_gid_lt), tbuf);
2182 		else
2183 			seq_printf(m, pt(Opt_gid_eq), tbuf);
2184 		seq_puts(m, " ");
2185 	}
2186 
2187 	if (entry->flags & IMA_EGID) {
2188 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2189 		if (entry->gid_op == &gid_gt)
2190 			seq_printf(m, pt(Opt_egid_gt), tbuf);
2191 		else if (entry->gid_op == &gid_lt)
2192 			seq_printf(m, pt(Opt_egid_lt), tbuf);
2193 		else
2194 			seq_printf(m, pt(Opt_egid_eq), tbuf);
2195 		seq_puts(m, " ");
2196 	}
2197 
2198 	if (entry->flags & IMA_FOWNER) {
2199 		snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2200 		if (entry->fowner_op == &vfsuid_gt_kuid)
2201 			seq_printf(m, pt(Opt_fowner_gt), tbuf);
2202 		else if (entry->fowner_op == &vfsuid_lt_kuid)
2203 			seq_printf(m, pt(Opt_fowner_lt), tbuf);
2204 		else
2205 			seq_printf(m, pt(Opt_fowner_eq), tbuf);
2206 		seq_puts(m, " ");
2207 	}
2208 
2209 	if (entry->flags & IMA_FGROUP) {
2210 		snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2211 		if (entry->fgroup_op == &vfsgid_gt_kgid)
2212 			seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2213 		else if (entry->fgroup_op == &vfsgid_lt_kgid)
2214 			seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2215 		else
2216 			seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2217 		seq_puts(m, " ");
2218 	}
2219 
2220 	if (entry->flags & IMA_VALIDATE_ALGOS) {
2221 		seq_puts(m, "appraise_algos=");
2222 		ima_policy_show_appraise_algos(m, entry->allowed_algos);
2223 		seq_puts(m, " ");
2224 	}
2225 
2226 	for (i = 0; i < MAX_LSM_RULES; i++) {
2227 		if (entry->lsm[i].rule) {
2228 			switch (i) {
2229 			case LSM_OBJ_USER:
2230 				seq_printf(m, pt(Opt_obj_user),
2231 					   entry->lsm[i].args_p);
2232 				break;
2233 			case LSM_OBJ_ROLE:
2234 				seq_printf(m, pt(Opt_obj_role),
2235 					   entry->lsm[i].args_p);
2236 				break;
2237 			case LSM_OBJ_TYPE:
2238 				seq_printf(m, pt(Opt_obj_type),
2239 					   entry->lsm[i].args_p);
2240 				break;
2241 			case LSM_SUBJ_USER:
2242 				seq_printf(m, pt(Opt_subj_user),
2243 					   entry->lsm[i].args_p);
2244 				break;
2245 			case LSM_SUBJ_ROLE:
2246 				seq_printf(m, pt(Opt_subj_role),
2247 					   entry->lsm[i].args_p);
2248 				break;
2249 			case LSM_SUBJ_TYPE:
2250 				seq_printf(m, pt(Opt_subj_type),
2251 					   entry->lsm[i].args_p);
2252 				break;
2253 			}
2254 			seq_puts(m, " ");
2255 		}
2256 	}
2257 	if (entry->template)
2258 		seq_printf(m, "template=%s ", entry->template->name);
2259 	if (entry->flags & IMA_DIGSIG_REQUIRED) {
2260 		if (entry->flags & IMA_VERITY_REQUIRED)
2261 			seq_puts(m, "appraise_type=sigv3 ");
2262 		else if (entry->flags & IMA_MODSIG_ALLOWED)
2263 			seq_puts(m, "appraise_type=imasig|modsig ");
2264 		else
2265 			seq_puts(m, "appraise_type=imasig ");
2266 	}
2267 	if (entry->flags & IMA_VERITY_REQUIRED)
2268 		seq_puts(m, "digest_type=verity ");
2269 	if (entry->flags & IMA_PERMIT_DIRECTIO)
2270 		seq_puts(m, "permit_directio ");
2271 	rcu_read_unlock();
2272 	seq_puts(m, "\n");
2273 	return 0;
2274 }
2275 #endif	/* CONFIG_IMA_READ_POLICY */
2276 
2277 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2278 /*
2279  * ima_appraise_signature: whether IMA will appraise a given function using
2280  * an IMA digital signature. This is restricted to cases where the kernel
2281  * has a set of built-in trusted keys in order to avoid an attacker simply
2282  * loading additional keys.
2283  */
2284 bool ima_appraise_signature(enum kernel_read_file_id id)
2285 {
2286 	struct ima_rule_entry *entry;
2287 	bool found = false;
2288 	enum ima_hooks func;
2289 	struct list_head *ima_rules_tmp;
2290 
2291 	if (id >= READING_MAX_ID)
2292 		return false;
2293 
2294 	if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2295 	    && security_locked_down(LOCKDOWN_KEXEC))
2296 		return false;
2297 
2298 	func = read_idmap[id] ?: FILE_CHECK;
2299 
2300 	rcu_read_lock();
2301 	ima_rules_tmp = rcu_dereference(ima_rules);
2302 	list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2303 		if (entry->action != APPRAISE)
2304 			continue;
2305 
2306 		/*
2307 		 * A generic entry will match, but otherwise require that it
2308 		 * match the func we're looking for
2309 		 */
2310 		if (entry->func && entry->func != func)
2311 			continue;
2312 
2313 		/*
2314 		 * We require this to be a digital signature, not a raw IMA
2315 		 * hash.
2316 		 */
2317 		if (entry->flags & IMA_DIGSIG_REQUIRED)
2318 			found = true;
2319 
2320 		/*
2321 		 * We've found a rule that matches, so break now even if it
2322 		 * didn't require a digital signature - a later rule that does
2323 		 * won't override it, so would be a false positive.
2324 		 */
2325 		break;
2326 	}
2327 
2328 	rcu_read_unlock();
2329 	return found;
2330 }
2331 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
2332