1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2008 IBM Corporation
4 * Author: Mimi Zohar <zohar@us.ibm.com>
5 *
6 * ima_policy.c
7 * - initialize default measure policy rules
8 */
9
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/kernel_read_file.h>
13 #include <linux/fs.h>
14 #include <linux/security.h>
15 #include <linux/magic.h>
16 #include <linux/parser.h>
17 #include <linux/slab.h>
18 #include <linux/rculist.h>
19 #include <linux/genhd.h>
20 #include <linux/seq_file.h>
21 #include <linux/ima.h>
22
23 #include "ima.h"
24
25 /* flags definitions */
26 #define IMA_FUNC 0x0001
27 #define IMA_MASK 0x0002
28 #define IMA_FSMAGIC 0x0004
29 #define IMA_UID 0x0008
30 #define IMA_FOWNER 0x0010
31 #define IMA_FSUUID 0x0020
32 #define IMA_INMASK 0x0040
33 #define IMA_EUID 0x0080
34 #define IMA_PCR 0x0100
35 #define IMA_FSNAME 0x0200
36 #define IMA_KEYRINGS 0x0400
37
38 #define UNKNOWN 0
39 #define MEASURE 0x0001 /* same as IMA_MEASURE */
40 #define DONT_MEASURE 0x0002
41 #define APPRAISE 0x0004 /* same as IMA_APPRAISE */
42 #define DONT_APPRAISE 0x0008
43 #define AUDIT 0x0040
44 #define HASH 0x0100
45 #define DONT_HASH 0x0200
46
47 #define INVALID_PCR(a) (((a) < 0) || \
48 (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
49
50 int ima_policy_flag;
51 static int temp_ima_appraise;
52 static int build_ima_appraise __ro_after_init;
53
54 #define MAX_LSM_RULES 6
55 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
56 LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
57 };
58
59 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
60
61 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
62
63 struct ima_rule_opt_list {
64 size_t count;
65 char *items[];
66 };
67
68 struct ima_rule_entry {
69 struct list_head list;
70 int action;
71 unsigned int flags;
72 enum ima_hooks func;
73 int mask;
74 unsigned long fsmagic;
75 uuid_t fsuuid;
76 kuid_t uid;
77 kuid_t fowner;
78 bool (*uid_op)(kuid_t, kuid_t); /* Handlers for operators */
79 bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
80 int pcr;
81 struct {
82 void *rule; /* LSM file metadata specific */
83 char *args_p; /* audit value */
84 int type; /* audit type */
85 } lsm[MAX_LSM_RULES];
86 char *fsname;
87 struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
88 struct ima_template_desc *template;
89 };
90
91 /*
92 * Without LSM specific knowledge, the default policy can only be
93 * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
94 */
95
96 /*
97 * The minimum rule set to allow for full TCB coverage. Measures all files
98 * opened or mmap for exec and everything read by root. Dangerous because
99 * normal users can easily run the machine out of memory simply building
100 * and running executables.
101 */
102 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
103 {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
104 {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
105 {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
106 {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
107 {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
108 {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
109 {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
110 {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
111 {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
112 {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
113 .flags = IMA_FSMAGIC},
114 {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
115 .flags = IMA_FSMAGIC},
116 {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
117 {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
118 };
119
120 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
121 {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
122 .flags = IMA_FUNC | IMA_MASK},
123 {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
124 .flags = IMA_FUNC | IMA_MASK},
125 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
126 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
127 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
128 {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
129 {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
130 };
131
132 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
133 {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
134 .flags = IMA_FUNC | IMA_MASK},
135 {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
136 .flags = IMA_FUNC | IMA_MASK},
137 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
138 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
139 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
140 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
141 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
142 .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
143 {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
144 {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
145 {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
146 };
147
148 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
149 {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
150 {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
151 {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
152 {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
153 {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
154 {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
155 {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
156 {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
157 {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
158 {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
159 {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
160 {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
161 {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
162 {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
163 #ifdef CONFIG_IMA_WRITE_POLICY
164 {.action = APPRAISE, .func = POLICY_CHECK,
165 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
166 #endif
167 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
168 {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
169 .flags = IMA_FOWNER},
170 #else
171 /* force signature */
172 {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
173 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
174 #endif
175 };
176
177 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
178 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
179 {.action = APPRAISE, .func = MODULE_CHECK,
180 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
181 #endif
182 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
183 {.action = APPRAISE, .func = FIRMWARE_CHECK,
184 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
185 #endif
186 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
187 {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
188 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
189 #endif
190 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
191 {.action = APPRAISE, .func = POLICY_CHECK,
192 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
193 #endif
194 };
195
196 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
197 {.action = APPRAISE, .func = MODULE_CHECK,
198 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
199 {.action = APPRAISE, .func = FIRMWARE_CHECK,
200 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
201 {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
202 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
203 {.action = APPRAISE, .func = POLICY_CHECK,
204 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
205 };
206
207 /* An array of architecture specific rules */
208 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
209
210 static LIST_HEAD(ima_default_rules);
211 static LIST_HEAD(ima_policy_rules);
212 static LIST_HEAD(ima_temp_rules);
213 static struct list_head *ima_rules = &ima_default_rules;
214
215 static int ima_policy __initdata;
216
default_measure_policy_setup(char * str)217 static int __init default_measure_policy_setup(char *str)
218 {
219 if (ima_policy)
220 return 1;
221
222 ima_policy = ORIGINAL_TCB;
223 return 1;
224 }
225 __setup("ima_tcb", default_measure_policy_setup);
226
227 static bool ima_use_appraise_tcb __initdata;
228 static bool ima_use_secure_boot __initdata;
229 static bool ima_fail_unverifiable_sigs __ro_after_init;
policy_setup(char * str)230 static int __init policy_setup(char *str)
231 {
232 char *p;
233
234 while ((p = strsep(&str, " |\n")) != NULL) {
235 if (*p == ' ')
236 continue;
237 if ((strcmp(p, "tcb") == 0) && !ima_policy)
238 ima_policy = DEFAULT_TCB;
239 else if (strcmp(p, "appraise_tcb") == 0)
240 ima_use_appraise_tcb = true;
241 else if (strcmp(p, "secure_boot") == 0)
242 ima_use_secure_boot = true;
243 else if (strcmp(p, "fail_securely") == 0)
244 ima_fail_unverifiable_sigs = true;
245 else
246 pr_err("policy \"%s\" not found", p);
247 }
248
249 return 1;
250 }
251 __setup("ima_policy=", policy_setup);
252
default_appraise_policy_setup(char * str)253 static int __init default_appraise_policy_setup(char *str)
254 {
255 ima_use_appraise_tcb = true;
256 return 1;
257 }
258 __setup("ima_appraise_tcb", default_appraise_policy_setup);
259
ima_alloc_rule_opt_list(const substring_t * src)260 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
261 {
262 struct ima_rule_opt_list *opt_list;
263 size_t count = 0;
264 char *src_copy;
265 char *cur, *next;
266 size_t i;
267
268 src_copy = match_strdup(src);
269 if (!src_copy)
270 return ERR_PTR(-ENOMEM);
271
272 next = src_copy;
273 while ((cur = strsep(&next, "|"))) {
274 /* Don't accept an empty list item */
275 if (!(*cur)) {
276 kfree(src_copy);
277 return ERR_PTR(-EINVAL);
278 }
279 count++;
280 }
281
282 /* Don't accept an empty list */
283 if (!count) {
284 kfree(src_copy);
285 return ERR_PTR(-EINVAL);
286 }
287
288 opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
289 if (!opt_list) {
290 kfree(src_copy);
291 return ERR_PTR(-ENOMEM);
292 }
293
294 /*
295 * strsep() has already replaced all instances of '|' with '\0',
296 * leaving a byte sequence of NUL-terminated strings. Reference each
297 * string with the array of items.
298 *
299 * IMPORTANT: Ownership of the allocated buffer is transferred from
300 * src_copy to the first element in the items array. To free the
301 * buffer, kfree() must only be called on the first element of the
302 * array.
303 */
304 for (i = 0, cur = src_copy; i < count; i++) {
305 opt_list->items[i] = cur;
306 cur = strchr(cur, '\0') + 1;
307 }
308 opt_list->count = count;
309
310 return opt_list;
311 }
312
ima_free_rule_opt_list(struct ima_rule_opt_list * opt_list)313 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
314 {
315 if (!opt_list)
316 return;
317
318 if (opt_list->count) {
319 kfree(opt_list->items[0]);
320 opt_list->count = 0;
321 }
322
323 kfree(opt_list);
324 }
325
ima_lsm_free_rule(struct ima_rule_entry * entry)326 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
327 {
328 int i;
329
330 for (i = 0; i < MAX_LSM_RULES; i++) {
331 ima_filter_rule_free(entry->lsm[i].rule);
332 kfree(entry->lsm[i].args_p);
333 }
334 }
335
ima_free_rule(struct ima_rule_entry * entry)336 static void ima_free_rule(struct ima_rule_entry *entry)
337 {
338 if (!entry)
339 return;
340
341 /*
342 * entry->template->fields may be allocated in ima_parse_rule() but that
343 * reference is owned by the corresponding ima_template_desc element in
344 * the defined_templates list and cannot be freed here
345 */
346 kfree(entry->fsname);
347 ima_free_rule_opt_list(entry->keyrings);
348 ima_lsm_free_rule(entry);
349 kfree(entry);
350 }
351
ima_lsm_copy_rule(struct ima_rule_entry * entry)352 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
353 {
354 struct ima_rule_entry *nentry;
355 int i;
356
357 /*
358 * Immutable elements are copied over as pointers and data; only
359 * lsm rules can change
360 */
361 nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
362 if (!nentry)
363 return NULL;
364
365 memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
366
367 for (i = 0; i < MAX_LSM_RULES; i++) {
368 if (!entry->lsm[i].args_p)
369 continue;
370
371 nentry->lsm[i].type = entry->lsm[i].type;
372 nentry->lsm[i].args_p = entry->lsm[i].args_p;
373
374 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
375 nentry->lsm[i].args_p,
376 &nentry->lsm[i].rule);
377 if (!nentry->lsm[i].rule)
378 pr_warn("rule for LSM \'%s\' is undefined\n",
379 nentry->lsm[i].args_p);
380 }
381 return nentry;
382 }
383
ima_lsm_update_rule(struct ima_rule_entry * entry)384 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
385 {
386 int i;
387 struct ima_rule_entry *nentry;
388
389 nentry = ima_lsm_copy_rule(entry);
390 if (!nentry)
391 return -ENOMEM;
392
393 list_replace_rcu(&entry->list, &nentry->list);
394 synchronize_rcu();
395 /*
396 * ima_lsm_copy_rule() shallow copied all references, except for the
397 * LSM references, from entry to nentry so we only want to free the LSM
398 * references and the entry itself. All other memory refrences will now
399 * be owned by nentry.
400 */
401 for (i = 0; i < MAX_LSM_RULES; i++)
402 ima_filter_rule_free(entry->lsm[i].rule);
403 kfree(entry);
404
405 return 0;
406 }
407
ima_rule_contains_lsm_cond(struct ima_rule_entry * entry)408 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
409 {
410 int i;
411
412 for (i = 0; i < MAX_LSM_RULES; i++)
413 if (entry->lsm[i].args_p)
414 return true;
415
416 return false;
417 }
418
419 /*
420 * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
421 * to the old, stale LSM policy. Update the IMA LSM based rules to reflect
422 * the reloaded LSM policy.
423 */
ima_lsm_update_rules(void)424 static void ima_lsm_update_rules(void)
425 {
426 struct ima_rule_entry *entry, *e;
427 int result;
428
429 list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
430 if (!ima_rule_contains_lsm_cond(entry))
431 continue;
432
433 result = ima_lsm_update_rule(entry);
434 if (result) {
435 pr_err("lsm rule update error %d\n", result);
436 return;
437 }
438 }
439 }
440
ima_lsm_policy_change(struct notifier_block * nb,unsigned long event,void * lsm_data)441 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
442 void *lsm_data)
443 {
444 if (event != LSM_POLICY_CHANGE)
445 return NOTIFY_DONE;
446
447 ima_lsm_update_rules();
448 return NOTIFY_OK;
449 }
450
451 /**
452 * ima_match_keyring - determine whether the keyring matches the measure rule
453 * @rule: a pointer to a rule
454 * @keyring: name of the keyring to match against the measure rule
455 * @cred: a pointer to a credentials structure for user validation
456 *
457 * Returns true if keyring matches one in the rule, false otherwise.
458 */
ima_match_keyring(struct ima_rule_entry * rule,const char * keyring,const struct cred * cred)459 static bool ima_match_keyring(struct ima_rule_entry *rule,
460 const char *keyring, const struct cred *cred)
461 {
462 bool matched = false;
463 size_t i;
464
465 if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
466 return false;
467
468 if (!rule->keyrings)
469 return true;
470
471 if (!keyring)
472 return false;
473
474 for (i = 0; i < rule->keyrings->count; i++) {
475 if (!strcmp(rule->keyrings->items[i], keyring)) {
476 matched = true;
477 break;
478 }
479 }
480
481 return matched;
482 }
483
484 /**
485 * ima_match_rules - determine whether an inode matches the policy rule.
486 * @rule: a pointer to a rule
487 * @inode: a pointer to an inode
488 * @cred: a pointer to a credentials structure for user validation
489 * @secid: the secid of the task to be validated
490 * @func: LIM hook identifier
491 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
492 * @keyring: keyring name to check in policy for KEY_CHECK func
493 *
494 * Returns true on rule match, false on failure.
495 */
ima_match_rules(struct ima_rule_entry * rule,struct inode * inode,const struct cred * cred,u32 secid,enum ima_hooks func,int mask,const char * keyring)496 static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
497 const struct cred *cred, u32 secid,
498 enum ima_hooks func, int mask,
499 const char *keyring)
500 {
501 int i;
502 bool result = false;
503 struct ima_rule_entry *lsm_rule = rule;
504 bool rule_reinitialized = false;
505
506 if (func == KEY_CHECK) {
507 return (rule->flags & IMA_FUNC) && (rule->func == func) &&
508 ima_match_keyring(rule, keyring, cred);
509 }
510 if ((rule->flags & IMA_FUNC) &&
511 (rule->func != func && func != POST_SETATTR))
512 return false;
513 if ((rule->flags & IMA_MASK) &&
514 (rule->mask != mask && func != POST_SETATTR))
515 return false;
516 if ((rule->flags & IMA_INMASK) &&
517 (!(rule->mask & mask) && func != POST_SETATTR))
518 return false;
519 if ((rule->flags & IMA_FSMAGIC)
520 && rule->fsmagic != inode->i_sb->s_magic)
521 return false;
522 if ((rule->flags & IMA_FSNAME)
523 && strcmp(rule->fsname, inode->i_sb->s_type->name))
524 return false;
525 if ((rule->flags & IMA_FSUUID) &&
526 !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
527 return false;
528 if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
529 return false;
530 if (rule->flags & IMA_EUID) {
531 if (has_capability_noaudit(current, CAP_SETUID)) {
532 if (!rule->uid_op(cred->euid, rule->uid)
533 && !rule->uid_op(cred->suid, rule->uid)
534 && !rule->uid_op(cred->uid, rule->uid))
535 return false;
536 } else if (!rule->uid_op(cred->euid, rule->uid))
537 return false;
538 }
539
540 if ((rule->flags & IMA_FOWNER) &&
541 !rule->fowner_op(inode->i_uid, rule->fowner))
542 return false;
543 for (i = 0; i < MAX_LSM_RULES; i++) {
544 int rc = 0;
545 u32 osid;
546
547 if (!lsm_rule->lsm[i].rule) {
548 if (!lsm_rule->lsm[i].args_p)
549 continue;
550 else
551 return false;
552 }
553
554 retry:
555 switch (i) {
556 case LSM_OBJ_USER:
557 case LSM_OBJ_ROLE:
558 case LSM_OBJ_TYPE:
559 security_inode_getsecid(inode, &osid);
560 rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
561 Audit_equal,
562 lsm_rule->lsm[i].rule);
563 break;
564 case LSM_SUBJ_USER:
565 case LSM_SUBJ_ROLE:
566 case LSM_SUBJ_TYPE:
567 rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
568 Audit_equal,
569 lsm_rule->lsm[i].rule);
570 break;
571 default:
572 break;
573 }
574
575 if (rc == -ESTALE && !rule_reinitialized) {
576 lsm_rule = ima_lsm_copy_rule(rule);
577 if (lsm_rule) {
578 rule_reinitialized = true;
579 goto retry;
580 }
581 }
582 if (!rc) {
583 result = false;
584 goto out;
585 }
586 }
587 result = true;
588
589 out:
590 if (rule_reinitialized) {
591 for (i = 0; i < MAX_LSM_RULES; i++)
592 ima_filter_rule_free(lsm_rule->lsm[i].rule);
593 kfree(lsm_rule);
594 }
595 return result;
596 }
597
598 /*
599 * In addition to knowing that we need to appraise the file in general,
600 * we need to differentiate between calling hooks, for hook specific rules.
601 */
get_subaction(struct ima_rule_entry * rule,enum ima_hooks func)602 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
603 {
604 if (!(rule->flags & IMA_FUNC))
605 return IMA_FILE_APPRAISE;
606
607 switch (func) {
608 case MMAP_CHECK:
609 return IMA_MMAP_APPRAISE;
610 case BPRM_CHECK:
611 return IMA_BPRM_APPRAISE;
612 case CREDS_CHECK:
613 return IMA_CREDS_APPRAISE;
614 case FILE_CHECK:
615 case POST_SETATTR:
616 return IMA_FILE_APPRAISE;
617 case MODULE_CHECK ... MAX_CHECK - 1:
618 default:
619 return IMA_READ_APPRAISE;
620 }
621 }
622
623 /**
624 * ima_match_policy - decision based on LSM and other conditions
625 * @inode: pointer to an inode for which the policy decision is being made
626 * @cred: pointer to a credentials structure for which the policy decision is
627 * being made
628 * @secid: LSM secid of the task to be validated
629 * @func: IMA hook identifier
630 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
631 * @pcr: set the pcr to extend
632 * @template_desc: the template that should be used for this rule
633 * @keyring: the keyring name, if given, to be used to check in the policy.
634 * keyring can be NULL if func is anything other than KEY_CHECK.
635 *
636 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
637 * conditions.
638 *
639 * Since the IMA policy may be updated multiple times we need to lock the
640 * list when walking it. Reads are many orders of magnitude more numerous
641 * than writes so ima_match_policy() is classical RCU candidate.
642 */
ima_match_policy(struct inode * inode,const struct cred * cred,u32 secid,enum ima_hooks func,int mask,int flags,int * pcr,struct ima_template_desc ** template_desc,const char * keyring)643 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
644 enum ima_hooks func, int mask, int flags, int *pcr,
645 struct ima_template_desc **template_desc,
646 const char *keyring)
647 {
648 struct ima_rule_entry *entry;
649 int action = 0, actmask = flags | (flags << 1);
650
651 if (template_desc)
652 *template_desc = ima_template_desc_current();
653
654 rcu_read_lock();
655 list_for_each_entry_rcu(entry, ima_rules, list) {
656
657 if (!(entry->action & actmask))
658 continue;
659
660 if (!ima_match_rules(entry, inode, cred, secid, func, mask,
661 keyring))
662 continue;
663
664 action |= entry->flags & IMA_ACTION_FLAGS;
665
666 action |= entry->action & IMA_DO_MASK;
667 if (entry->action & IMA_APPRAISE) {
668 action |= get_subaction(entry, func);
669 action &= ~IMA_HASH;
670 if (ima_fail_unverifiable_sigs)
671 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
672 }
673
674
675 if (entry->action & IMA_DO_MASK)
676 actmask &= ~(entry->action | entry->action << 1);
677 else
678 actmask &= ~(entry->action | entry->action >> 1);
679
680 if ((pcr) && (entry->flags & IMA_PCR))
681 *pcr = entry->pcr;
682
683 if (template_desc && entry->template)
684 *template_desc = entry->template;
685
686 if (!actmask)
687 break;
688 }
689 rcu_read_unlock();
690
691 return action;
692 }
693
694 /*
695 * Initialize the ima_policy_flag variable based on the currently
696 * loaded policy. Based on this flag, the decision to short circuit
697 * out of a function or not call the function in the first place
698 * can be made earlier.
699 */
ima_update_policy_flag(void)700 void ima_update_policy_flag(void)
701 {
702 struct ima_rule_entry *entry;
703
704 list_for_each_entry(entry, ima_rules, list) {
705 if (entry->action & IMA_DO_MASK)
706 ima_policy_flag |= entry->action;
707 }
708
709 ima_appraise |= (build_ima_appraise | temp_ima_appraise);
710 if (!ima_appraise)
711 ima_policy_flag &= ~IMA_APPRAISE;
712 }
713
ima_appraise_flag(enum ima_hooks func)714 static int ima_appraise_flag(enum ima_hooks func)
715 {
716 if (func == MODULE_CHECK)
717 return IMA_APPRAISE_MODULES;
718 else if (func == FIRMWARE_CHECK)
719 return IMA_APPRAISE_FIRMWARE;
720 else if (func == POLICY_CHECK)
721 return IMA_APPRAISE_POLICY;
722 else if (func == KEXEC_KERNEL_CHECK)
723 return IMA_APPRAISE_KEXEC;
724 return 0;
725 }
726
add_rules(struct ima_rule_entry * entries,int count,enum policy_rule_list policy_rule)727 static void add_rules(struct ima_rule_entry *entries, int count,
728 enum policy_rule_list policy_rule)
729 {
730 int i = 0;
731
732 for (i = 0; i < count; i++) {
733 struct ima_rule_entry *entry;
734
735 if (policy_rule & IMA_DEFAULT_POLICY)
736 list_add_tail(&entries[i].list, &ima_default_rules);
737
738 if (policy_rule & IMA_CUSTOM_POLICY) {
739 entry = kmemdup(&entries[i], sizeof(*entry),
740 GFP_KERNEL);
741 if (!entry)
742 continue;
743
744 list_add_tail(&entry->list, &ima_policy_rules);
745 }
746 if (entries[i].action == APPRAISE) {
747 if (entries != build_appraise_rules)
748 temp_ima_appraise |=
749 ima_appraise_flag(entries[i].func);
750 else
751 build_ima_appraise |=
752 ima_appraise_flag(entries[i].func);
753 }
754 }
755 }
756
757 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
758
ima_init_arch_policy(void)759 static int __init ima_init_arch_policy(void)
760 {
761 const char * const *arch_rules;
762 const char * const *rules;
763 int arch_entries = 0;
764 int i = 0;
765
766 arch_rules = arch_get_ima_policy();
767 if (!arch_rules)
768 return arch_entries;
769
770 /* Get number of rules */
771 for (rules = arch_rules; *rules != NULL; rules++)
772 arch_entries++;
773
774 arch_policy_entry = kcalloc(arch_entries + 1,
775 sizeof(*arch_policy_entry), GFP_KERNEL);
776 if (!arch_policy_entry)
777 return 0;
778
779 /* Convert each policy string rules to struct ima_rule_entry format */
780 for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
781 char rule[255];
782 int result;
783
784 result = strlcpy(rule, *rules, sizeof(rule));
785
786 INIT_LIST_HEAD(&arch_policy_entry[i].list);
787 result = ima_parse_rule(rule, &arch_policy_entry[i]);
788 if (result) {
789 pr_warn("Skipping unknown architecture policy rule: %s\n",
790 rule);
791 memset(&arch_policy_entry[i], 0,
792 sizeof(*arch_policy_entry));
793 continue;
794 }
795 i++;
796 }
797 return i;
798 }
799
800 /**
801 * ima_init_policy - initialize the default measure rules.
802 *
803 * ima_rules points to either the ima_default_rules or the
804 * the new ima_policy_rules.
805 */
ima_init_policy(void)806 void __init ima_init_policy(void)
807 {
808 int build_appraise_entries, arch_entries;
809
810 /* if !ima_policy, we load NO default rules */
811 if (ima_policy)
812 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
813 IMA_DEFAULT_POLICY);
814
815 switch (ima_policy) {
816 case ORIGINAL_TCB:
817 add_rules(original_measurement_rules,
818 ARRAY_SIZE(original_measurement_rules),
819 IMA_DEFAULT_POLICY);
820 break;
821 case DEFAULT_TCB:
822 add_rules(default_measurement_rules,
823 ARRAY_SIZE(default_measurement_rules),
824 IMA_DEFAULT_POLICY);
825 break;
826 default:
827 break;
828 }
829
830 /*
831 * Based on runtime secure boot flags, insert arch specific measurement
832 * and appraise rules requiring file signatures for both the initial
833 * and custom policies, prior to other appraise rules.
834 * (Highest priority)
835 */
836 arch_entries = ima_init_arch_policy();
837 if (!arch_entries)
838 pr_info("No architecture policies found\n");
839 else
840 add_rules(arch_policy_entry, arch_entries,
841 IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
842
843 /*
844 * Insert the builtin "secure_boot" policy rules requiring file
845 * signatures, prior to other appraise rules.
846 */
847 if (ima_use_secure_boot)
848 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
849 IMA_DEFAULT_POLICY);
850
851 /*
852 * Insert the build time appraise rules requiring file signatures
853 * for both the initial and custom policies, prior to other appraise
854 * rules. As the secure boot rules includes all of the build time
855 * rules, include either one or the other set of rules, but not both.
856 */
857 build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
858 if (build_appraise_entries) {
859 if (ima_use_secure_boot)
860 add_rules(build_appraise_rules, build_appraise_entries,
861 IMA_CUSTOM_POLICY);
862 else
863 add_rules(build_appraise_rules, build_appraise_entries,
864 IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
865 }
866
867 if (ima_use_appraise_tcb)
868 add_rules(default_appraise_rules,
869 ARRAY_SIZE(default_appraise_rules),
870 IMA_DEFAULT_POLICY);
871
872 ima_update_policy_flag();
873 }
874
875 /* Make sure we have a valid policy, at least containing some rules. */
ima_check_policy(void)876 int ima_check_policy(void)
877 {
878 if (list_empty(&ima_temp_rules))
879 return -EINVAL;
880 return 0;
881 }
882
883 /**
884 * ima_update_policy - update default_rules with new measure rules
885 *
886 * Called on file .release to update the default rules with a complete new
887 * policy. What we do here is to splice ima_policy_rules and ima_temp_rules so
888 * they make a queue. The policy may be updated multiple times and this is the
889 * RCU updater.
890 *
891 * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
892 * we switch from the default policy to user defined.
893 */
ima_update_policy(void)894 void ima_update_policy(void)
895 {
896 struct list_head *policy = &ima_policy_rules;
897
898 list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
899
900 if (ima_rules != policy) {
901 ima_policy_flag = 0;
902 ima_rules = policy;
903
904 /*
905 * IMA architecture specific policy rules are specified
906 * as strings and converted to an array of ima_entry_rules
907 * on boot. After loading a custom policy, free the
908 * architecture specific rules stored as an array.
909 */
910 kfree(arch_policy_entry);
911 }
912 ima_update_policy_flag();
913
914 /* Custom IMA policy has been loaded */
915 ima_process_queued_keys();
916 }
917
918 /* Keep the enumeration in sync with the policy_tokens! */
919 enum {
920 Opt_measure, Opt_dont_measure,
921 Opt_appraise, Opt_dont_appraise,
922 Opt_audit, Opt_hash, Opt_dont_hash,
923 Opt_obj_user, Opt_obj_role, Opt_obj_type,
924 Opt_subj_user, Opt_subj_role, Opt_subj_type,
925 Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
926 Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
927 Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
928 Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
929 Opt_appraise_type, Opt_appraise_flag,
930 Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
931 Opt_err
932 };
933
934 static const match_table_t policy_tokens = {
935 {Opt_measure, "measure"},
936 {Opt_dont_measure, "dont_measure"},
937 {Opt_appraise, "appraise"},
938 {Opt_dont_appraise, "dont_appraise"},
939 {Opt_audit, "audit"},
940 {Opt_hash, "hash"},
941 {Opt_dont_hash, "dont_hash"},
942 {Opt_obj_user, "obj_user=%s"},
943 {Opt_obj_role, "obj_role=%s"},
944 {Opt_obj_type, "obj_type=%s"},
945 {Opt_subj_user, "subj_user=%s"},
946 {Opt_subj_role, "subj_role=%s"},
947 {Opt_subj_type, "subj_type=%s"},
948 {Opt_func, "func=%s"},
949 {Opt_mask, "mask=%s"},
950 {Opt_fsmagic, "fsmagic=%s"},
951 {Opt_fsname, "fsname=%s"},
952 {Opt_fsuuid, "fsuuid=%s"},
953 {Opt_uid_eq, "uid=%s"},
954 {Opt_euid_eq, "euid=%s"},
955 {Opt_fowner_eq, "fowner=%s"},
956 {Opt_uid_gt, "uid>%s"},
957 {Opt_euid_gt, "euid>%s"},
958 {Opt_fowner_gt, "fowner>%s"},
959 {Opt_uid_lt, "uid<%s"},
960 {Opt_euid_lt, "euid<%s"},
961 {Opt_fowner_lt, "fowner<%s"},
962 {Opt_appraise_type, "appraise_type=%s"},
963 {Opt_appraise_flag, "appraise_flag=%s"},
964 {Opt_permit_directio, "permit_directio"},
965 {Opt_pcr, "pcr=%s"},
966 {Opt_template, "template=%s"},
967 {Opt_keyrings, "keyrings=%s"},
968 {Opt_err, NULL}
969 };
970
ima_lsm_rule_init(struct ima_rule_entry * entry,substring_t * args,int lsm_rule,int audit_type)971 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
972 substring_t *args, int lsm_rule, int audit_type)
973 {
974 int result;
975
976 if (entry->lsm[lsm_rule].rule)
977 return -EINVAL;
978
979 entry->lsm[lsm_rule].args_p = match_strdup(args);
980 if (!entry->lsm[lsm_rule].args_p)
981 return -ENOMEM;
982
983 entry->lsm[lsm_rule].type = audit_type;
984 result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
985 entry->lsm[lsm_rule].args_p,
986 &entry->lsm[lsm_rule].rule);
987 if (!entry->lsm[lsm_rule].rule) {
988 pr_warn("rule for LSM \'%s\' is undefined\n",
989 entry->lsm[lsm_rule].args_p);
990
991 if (ima_rules == &ima_default_rules) {
992 kfree(entry->lsm[lsm_rule].args_p);
993 entry->lsm[lsm_rule].args_p = NULL;
994 result = -EINVAL;
995 } else
996 result = 0;
997 }
998
999 return result;
1000 }
1001
ima_log_string_op(struct audit_buffer * ab,char * key,char * value,bool (* rule_operator)(kuid_t,kuid_t))1002 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1003 bool (*rule_operator)(kuid_t, kuid_t))
1004 {
1005 if (!ab)
1006 return;
1007
1008 if (rule_operator == &uid_gt)
1009 audit_log_format(ab, "%s>", key);
1010 else if (rule_operator == &uid_lt)
1011 audit_log_format(ab, "%s<", key);
1012 else
1013 audit_log_format(ab, "%s=", key);
1014 audit_log_format(ab, "%s ", value);
1015 }
ima_log_string(struct audit_buffer * ab,char * key,char * value)1016 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1017 {
1018 ima_log_string_op(ab, key, value, NULL);
1019 }
1020
1021 /*
1022 * Validating the appended signature included in the measurement list requires
1023 * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1024 * field). Therefore, notify the user if they have the 'modsig' field but not
1025 * the 'd-modsig' field in the template.
1026 */
check_template_modsig(const struct ima_template_desc * template)1027 static void check_template_modsig(const struct ima_template_desc *template)
1028 {
1029 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1030 bool has_modsig, has_dmodsig;
1031 static bool checked;
1032 int i;
1033
1034 /* We only need to notify the user once. */
1035 if (checked)
1036 return;
1037
1038 has_modsig = has_dmodsig = false;
1039 for (i = 0; i < template->num_fields; i++) {
1040 if (!strcmp(template->fields[i]->field_id, "modsig"))
1041 has_modsig = true;
1042 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1043 has_dmodsig = true;
1044 }
1045
1046 if (has_modsig && !has_dmodsig)
1047 pr_notice(MSG);
1048
1049 checked = true;
1050 #undef MSG
1051 }
1052
ima_validate_rule(struct ima_rule_entry * entry)1053 static bool ima_validate_rule(struct ima_rule_entry *entry)
1054 {
1055 /* Ensure that the action is set and is compatible with the flags */
1056 if (entry->action == UNKNOWN)
1057 return false;
1058
1059 if (entry->action != MEASURE && entry->flags & IMA_PCR)
1060 return false;
1061
1062 if (entry->action != APPRAISE &&
1063 entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
1064 return false;
1065
1066 /*
1067 * The IMA_FUNC bit must be set if and only if there's a valid hook
1068 * function specified, and vice versa. Enforcing this property allows
1069 * for the NONE case below to validate a rule without an explicit hook
1070 * function.
1071 */
1072 if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1073 (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1074 return false;
1075
1076 /*
1077 * Ensure that the hook function is compatible with the other
1078 * components of the rule
1079 */
1080 switch (entry->func) {
1081 case NONE:
1082 case FILE_CHECK:
1083 case MMAP_CHECK:
1084 case BPRM_CHECK:
1085 case CREDS_CHECK:
1086 case POST_SETATTR:
1087 case FIRMWARE_CHECK:
1088 case POLICY_CHECK:
1089 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1090 IMA_UID | IMA_FOWNER | IMA_FSUUID |
1091 IMA_INMASK | IMA_EUID | IMA_PCR |
1092 IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1093 IMA_PERMIT_DIRECTIO))
1094 return false;
1095
1096 break;
1097 case MODULE_CHECK:
1098 case KEXEC_KERNEL_CHECK:
1099 case KEXEC_INITRAMFS_CHECK:
1100 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1101 IMA_UID | IMA_FOWNER | IMA_FSUUID |
1102 IMA_INMASK | IMA_EUID | IMA_PCR |
1103 IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1104 IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1105 IMA_CHECK_BLACKLIST))
1106 return false;
1107
1108 break;
1109 case KEXEC_CMDLINE:
1110 if (entry->action & ~(MEASURE | DONT_MEASURE))
1111 return false;
1112
1113 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1114 IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1115 IMA_PCR | IMA_FSNAME))
1116 return false;
1117
1118 break;
1119 case KEY_CHECK:
1120 if (entry->action & ~(MEASURE | DONT_MEASURE))
1121 return false;
1122
1123 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1124 IMA_KEYRINGS))
1125 return false;
1126
1127 if (ima_rule_contains_lsm_cond(entry))
1128 return false;
1129
1130 break;
1131 default:
1132 return false;
1133 }
1134
1135 /* Ensure that combinations of flags are compatible with each other */
1136 if (entry->flags & IMA_CHECK_BLACKLIST &&
1137 !(entry->flags & IMA_MODSIG_ALLOWED))
1138 return false;
1139
1140 return true;
1141 }
1142
ima_parse_rule(char * rule,struct ima_rule_entry * entry)1143 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1144 {
1145 struct audit_buffer *ab;
1146 char *from;
1147 char *p;
1148 bool uid_token;
1149 struct ima_template_desc *template_desc;
1150 int result = 0;
1151
1152 ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1153 AUDIT_INTEGRITY_POLICY_RULE);
1154
1155 entry->uid = INVALID_UID;
1156 entry->fowner = INVALID_UID;
1157 entry->uid_op = &uid_eq;
1158 entry->fowner_op = &uid_eq;
1159 entry->action = UNKNOWN;
1160 while ((p = strsep(&rule, " \t")) != NULL) {
1161 substring_t args[MAX_OPT_ARGS];
1162 int token;
1163 unsigned long lnum;
1164
1165 if (result < 0)
1166 break;
1167 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1168 continue;
1169 token = match_token(p, policy_tokens, args);
1170 switch (token) {
1171 case Opt_measure:
1172 ima_log_string(ab, "action", "measure");
1173
1174 if (entry->action != UNKNOWN)
1175 result = -EINVAL;
1176
1177 entry->action = MEASURE;
1178 break;
1179 case Opt_dont_measure:
1180 ima_log_string(ab, "action", "dont_measure");
1181
1182 if (entry->action != UNKNOWN)
1183 result = -EINVAL;
1184
1185 entry->action = DONT_MEASURE;
1186 break;
1187 case Opt_appraise:
1188 ima_log_string(ab, "action", "appraise");
1189
1190 if (entry->action != UNKNOWN)
1191 result = -EINVAL;
1192
1193 entry->action = APPRAISE;
1194 break;
1195 case Opt_dont_appraise:
1196 ima_log_string(ab, "action", "dont_appraise");
1197
1198 if (entry->action != UNKNOWN)
1199 result = -EINVAL;
1200
1201 entry->action = DONT_APPRAISE;
1202 break;
1203 case Opt_audit:
1204 ima_log_string(ab, "action", "audit");
1205
1206 if (entry->action != UNKNOWN)
1207 result = -EINVAL;
1208
1209 entry->action = AUDIT;
1210 break;
1211 case Opt_hash:
1212 ima_log_string(ab, "action", "hash");
1213
1214 if (entry->action != UNKNOWN)
1215 result = -EINVAL;
1216
1217 entry->action = HASH;
1218 break;
1219 case Opt_dont_hash:
1220 ima_log_string(ab, "action", "dont_hash");
1221
1222 if (entry->action != UNKNOWN)
1223 result = -EINVAL;
1224
1225 entry->action = DONT_HASH;
1226 break;
1227 case Opt_func:
1228 ima_log_string(ab, "func", args[0].from);
1229
1230 if (entry->func)
1231 result = -EINVAL;
1232
1233 if (strcmp(args[0].from, "FILE_CHECK") == 0)
1234 entry->func = FILE_CHECK;
1235 /* PATH_CHECK is for backwards compat */
1236 else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1237 entry->func = FILE_CHECK;
1238 else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1239 entry->func = MODULE_CHECK;
1240 else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1241 entry->func = FIRMWARE_CHECK;
1242 else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1243 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1244 entry->func = MMAP_CHECK;
1245 else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1246 entry->func = BPRM_CHECK;
1247 else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1248 entry->func = CREDS_CHECK;
1249 else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1250 0)
1251 entry->func = KEXEC_KERNEL_CHECK;
1252 else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1253 == 0)
1254 entry->func = KEXEC_INITRAMFS_CHECK;
1255 else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1256 entry->func = POLICY_CHECK;
1257 else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1258 entry->func = KEXEC_CMDLINE;
1259 else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1260 strcmp(args[0].from, "KEY_CHECK") == 0)
1261 entry->func = KEY_CHECK;
1262 else
1263 result = -EINVAL;
1264 if (!result)
1265 entry->flags |= IMA_FUNC;
1266 break;
1267 case Opt_mask:
1268 ima_log_string(ab, "mask", args[0].from);
1269
1270 if (entry->mask)
1271 result = -EINVAL;
1272
1273 from = args[0].from;
1274 if (*from == '^')
1275 from++;
1276
1277 if ((strcmp(from, "MAY_EXEC")) == 0)
1278 entry->mask = MAY_EXEC;
1279 else if (strcmp(from, "MAY_WRITE") == 0)
1280 entry->mask = MAY_WRITE;
1281 else if (strcmp(from, "MAY_READ") == 0)
1282 entry->mask = MAY_READ;
1283 else if (strcmp(from, "MAY_APPEND") == 0)
1284 entry->mask = MAY_APPEND;
1285 else
1286 result = -EINVAL;
1287 if (!result)
1288 entry->flags |= (*args[0].from == '^')
1289 ? IMA_INMASK : IMA_MASK;
1290 break;
1291 case Opt_fsmagic:
1292 ima_log_string(ab, "fsmagic", args[0].from);
1293
1294 if (entry->fsmagic) {
1295 result = -EINVAL;
1296 break;
1297 }
1298
1299 result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1300 if (!result)
1301 entry->flags |= IMA_FSMAGIC;
1302 break;
1303 case Opt_fsname:
1304 ima_log_string(ab, "fsname", args[0].from);
1305
1306 entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1307 if (!entry->fsname) {
1308 result = -ENOMEM;
1309 break;
1310 }
1311 result = 0;
1312 entry->flags |= IMA_FSNAME;
1313 break;
1314 case Opt_keyrings:
1315 ima_log_string(ab, "keyrings", args[0].from);
1316
1317 if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1318 entry->keyrings) {
1319 result = -EINVAL;
1320 break;
1321 }
1322
1323 entry->keyrings = ima_alloc_rule_opt_list(args);
1324 if (IS_ERR(entry->keyrings)) {
1325 result = PTR_ERR(entry->keyrings);
1326 entry->keyrings = NULL;
1327 break;
1328 }
1329
1330 entry->flags |= IMA_KEYRINGS;
1331 break;
1332 case Opt_fsuuid:
1333 ima_log_string(ab, "fsuuid", args[0].from);
1334
1335 if (!uuid_is_null(&entry->fsuuid)) {
1336 result = -EINVAL;
1337 break;
1338 }
1339
1340 result = uuid_parse(args[0].from, &entry->fsuuid);
1341 if (!result)
1342 entry->flags |= IMA_FSUUID;
1343 break;
1344 case Opt_uid_gt:
1345 case Opt_euid_gt:
1346 entry->uid_op = &uid_gt;
1347 fallthrough;
1348 case Opt_uid_lt:
1349 case Opt_euid_lt:
1350 if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1351 entry->uid_op = &uid_lt;
1352 fallthrough;
1353 case Opt_uid_eq:
1354 case Opt_euid_eq:
1355 uid_token = (token == Opt_uid_eq) ||
1356 (token == Opt_uid_gt) ||
1357 (token == Opt_uid_lt);
1358
1359 ima_log_string_op(ab, uid_token ? "uid" : "euid",
1360 args[0].from, entry->uid_op);
1361
1362 if (uid_valid(entry->uid)) {
1363 result = -EINVAL;
1364 break;
1365 }
1366
1367 result = kstrtoul(args[0].from, 10, &lnum);
1368 if (!result) {
1369 entry->uid = make_kuid(current_user_ns(),
1370 (uid_t) lnum);
1371 if (!uid_valid(entry->uid) ||
1372 (uid_t)lnum != lnum)
1373 result = -EINVAL;
1374 else
1375 entry->flags |= uid_token
1376 ? IMA_UID : IMA_EUID;
1377 }
1378 break;
1379 case Opt_fowner_gt:
1380 entry->fowner_op = &uid_gt;
1381 fallthrough;
1382 case Opt_fowner_lt:
1383 if (token == Opt_fowner_lt)
1384 entry->fowner_op = &uid_lt;
1385 fallthrough;
1386 case Opt_fowner_eq:
1387 ima_log_string_op(ab, "fowner", args[0].from,
1388 entry->fowner_op);
1389
1390 if (uid_valid(entry->fowner)) {
1391 result = -EINVAL;
1392 break;
1393 }
1394
1395 result = kstrtoul(args[0].from, 10, &lnum);
1396 if (!result) {
1397 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
1398 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
1399 result = -EINVAL;
1400 else
1401 entry->flags |= IMA_FOWNER;
1402 }
1403 break;
1404 case Opt_obj_user:
1405 ima_log_string(ab, "obj_user", args[0].from);
1406 result = ima_lsm_rule_init(entry, args,
1407 LSM_OBJ_USER,
1408 AUDIT_OBJ_USER);
1409 break;
1410 case Opt_obj_role:
1411 ima_log_string(ab, "obj_role", args[0].from);
1412 result = ima_lsm_rule_init(entry, args,
1413 LSM_OBJ_ROLE,
1414 AUDIT_OBJ_ROLE);
1415 break;
1416 case Opt_obj_type:
1417 ima_log_string(ab, "obj_type", args[0].from);
1418 result = ima_lsm_rule_init(entry, args,
1419 LSM_OBJ_TYPE,
1420 AUDIT_OBJ_TYPE);
1421 break;
1422 case Opt_subj_user:
1423 ima_log_string(ab, "subj_user", args[0].from);
1424 result = ima_lsm_rule_init(entry, args,
1425 LSM_SUBJ_USER,
1426 AUDIT_SUBJ_USER);
1427 break;
1428 case Opt_subj_role:
1429 ima_log_string(ab, "subj_role", args[0].from);
1430 result = ima_lsm_rule_init(entry, args,
1431 LSM_SUBJ_ROLE,
1432 AUDIT_SUBJ_ROLE);
1433 break;
1434 case Opt_subj_type:
1435 ima_log_string(ab, "subj_type", args[0].from);
1436 result = ima_lsm_rule_init(entry, args,
1437 LSM_SUBJ_TYPE,
1438 AUDIT_SUBJ_TYPE);
1439 break;
1440 case Opt_appraise_type:
1441 ima_log_string(ab, "appraise_type", args[0].from);
1442 if ((strcmp(args[0].from, "imasig")) == 0)
1443 entry->flags |= IMA_DIGSIG_REQUIRED;
1444 else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1445 strcmp(args[0].from, "imasig|modsig") == 0)
1446 entry->flags |= IMA_DIGSIG_REQUIRED |
1447 IMA_MODSIG_ALLOWED;
1448 else
1449 result = -EINVAL;
1450 break;
1451 case Opt_appraise_flag:
1452 ima_log_string(ab, "appraise_flag", args[0].from);
1453 if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1454 strstr(args[0].from, "blacklist"))
1455 entry->flags |= IMA_CHECK_BLACKLIST;
1456 else
1457 result = -EINVAL;
1458 break;
1459 case Opt_permit_directio:
1460 entry->flags |= IMA_PERMIT_DIRECTIO;
1461 break;
1462 case Opt_pcr:
1463 ima_log_string(ab, "pcr", args[0].from);
1464
1465 result = kstrtoint(args[0].from, 10, &entry->pcr);
1466 if (result || INVALID_PCR(entry->pcr))
1467 result = -EINVAL;
1468 else
1469 entry->flags |= IMA_PCR;
1470
1471 break;
1472 case Opt_template:
1473 ima_log_string(ab, "template", args[0].from);
1474 if (entry->action != MEASURE) {
1475 result = -EINVAL;
1476 break;
1477 }
1478 template_desc = lookup_template_desc(args[0].from);
1479 if (!template_desc || entry->template) {
1480 result = -EINVAL;
1481 break;
1482 }
1483
1484 /*
1485 * template_desc_init_fields() does nothing if
1486 * the template is already initialised, so
1487 * it's safe to do this unconditionally
1488 */
1489 template_desc_init_fields(template_desc->fmt,
1490 &(template_desc->fields),
1491 &(template_desc->num_fields));
1492 entry->template = template_desc;
1493 break;
1494 case Opt_err:
1495 ima_log_string(ab, "UNKNOWN", p);
1496 result = -EINVAL;
1497 break;
1498 }
1499 }
1500 if (!result && !ima_validate_rule(entry))
1501 result = -EINVAL;
1502 else if (entry->action == APPRAISE)
1503 temp_ima_appraise |= ima_appraise_flag(entry->func);
1504
1505 if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1506 template_desc = entry->template ? entry->template :
1507 ima_template_desc_current();
1508 check_template_modsig(template_desc);
1509 }
1510
1511 audit_log_format(ab, "res=%d", !result);
1512 audit_log_end(ab);
1513 return result;
1514 }
1515
1516 /**
1517 * ima_parse_add_rule - add a rule to ima_policy_rules
1518 * @rule - ima measurement policy rule
1519 *
1520 * Avoid locking by allowing just one writer at a time in ima_write_policy()
1521 * Returns the length of the rule parsed, an error code on failure
1522 */
ima_parse_add_rule(char * rule)1523 ssize_t ima_parse_add_rule(char *rule)
1524 {
1525 static const char op[] = "update_policy";
1526 char *p;
1527 struct ima_rule_entry *entry;
1528 ssize_t result, len;
1529 int audit_info = 0;
1530
1531 p = strsep(&rule, "\n");
1532 len = strlen(p) + 1;
1533 p += strspn(p, " \t");
1534
1535 if (*p == '#' || *p == '\0')
1536 return len;
1537
1538 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1539 if (!entry) {
1540 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1541 NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1542 return -ENOMEM;
1543 }
1544
1545 INIT_LIST_HEAD(&entry->list);
1546
1547 result = ima_parse_rule(p, entry);
1548 if (result) {
1549 ima_free_rule(entry);
1550 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1551 NULL, op, "invalid-policy", result,
1552 audit_info);
1553 return result;
1554 }
1555
1556 list_add_tail(&entry->list, &ima_temp_rules);
1557
1558 return len;
1559 }
1560
1561 /**
1562 * ima_delete_rules() called to cleanup invalid in-flight policy.
1563 * We don't need locking as we operate on the temp list, which is
1564 * different from the active one. There is also only one user of
1565 * ima_delete_rules() at a time.
1566 */
ima_delete_rules(void)1567 void ima_delete_rules(void)
1568 {
1569 struct ima_rule_entry *entry, *tmp;
1570
1571 temp_ima_appraise = 0;
1572 list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1573 list_del(&entry->list);
1574 ima_free_rule(entry);
1575 }
1576 }
1577
1578 #define __ima_hook_stringify(func, str) (#func),
1579
1580 const char *const func_tokens[] = {
1581 __ima_hooks(__ima_hook_stringify)
1582 };
1583
1584 #ifdef CONFIG_IMA_READ_POLICY
1585 enum {
1586 mask_exec = 0, mask_write, mask_read, mask_append
1587 };
1588
1589 static const char *const mask_tokens[] = {
1590 "^MAY_EXEC",
1591 "^MAY_WRITE",
1592 "^MAY_READ",
1593 "^MAY_APPEND"
1594 };
1595
ima_policy_start(struct seq_file * m,loff_t * pos)1596 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1597 {
1598 loff_t l = *pos;
1599 struct ima_rule_entry *entry;
1600
1601 rcu_read_lock();
1602 list_for_each_entry_rcu(entry, ima_rules, list) {
1603 if (!l--) {
1604 rcu_read_unlock();
1605 return entry;
1606 }
1607 }
1608 rcu_read_unlock();
1609 return NULL;
1610 }
1611
ima_policy_next(struct seq_file * m,void * v,loff_t * pos)1612 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1613 {
1614 struct ima_rule_entry *entry = v;
1615
1616 rcu_read_lock();
1617 entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1618 rcu_read_unlock();
1619 (*pos)++;
1620
1621 return (&entry->list == ima_rules) ? NULL : entry;
1622 }
1623
ima_policy_stop(struct seq_file * m,void * v)1624 void ima_policy_stop(struct seq_file *m, void *v)
1625 {
1626 }
1627
1628 #define pt(token) policy_tokens[token].pattern
1629 #define mt(token) mask_tokens[token]
1630
1631 /*
1632 * policy_func_show - display the ima_hooks policy rule
1633 */
policy_func_show(struct seq_file * m,enum ima_hooks func)1634 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1635 {
1636 if (func > 0 && func < MAX_CHECK)
1637 seq_printf(m, "func=%s ", func_tokens[func]);
1638 else
1639 seq_printf(m, "func=%d ", func);
1640 }
1641
ima_show_rule_opt_list(struct seq_file * m,const struct ima_rule_opt_list * opt_list)1642 static void ima_show_rule_opt_list(struct seq_file *m,
1643 const struct ima_rule_opt_list *opt_list)
1644 {
1645 size_t i;
1646
1647 for (i = 0; i < opt_list->count; i++)
1648 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
1649 }
1650
ima_policy_show(struct seq_file * m,void * v)1651 int ima_policy_show(struct seq_file *m, void *v)
1652 {
1653 struct ima_rule_entry *entry = v;
1654 int i;
1655 char tbuf[64] = {0,};
1656 int offset = 0;
1657
1658 rcu_read_lock();
1659
1660 /* Do not print rules with inactive LSM labels */
1661 for (i = 0; i < MAX_LSM_RULES; i++) {
1662 if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
1663 rcu_read_unlock();
1664 return 0;
1665 }
1666 }
1667
1668 if (entry->action & MEASURE)
1669 seq_puts(m, pt(Opt_measure));
1670 if (entry->action & DONT_MEASURE)
1671 seq_puts(m, pt(Opt_dont_measure));
1672 if (entry->action & APPRAISE)
1673 seq_puts(m, pt(Opt_appraise));
1674 if (entry->action & DONT_APPRAISE)
1675 seq_puts(m, pt(Opt_dont_appraise));
1676 if (entry->action & AUDIT)
1677 seq_puts(m, pt(Opt_audit));
1678 if (entry->action & HASH)
1679 seq_puts(m, pt(Opt_hash));
1680 if (entry->action & DONT_HASH)
1681 seq_puts(m, pt(Opt_dont_hash));
1682
1683 seq_puts(m, " ");
1684
1685 if (entry->flags & IMA_FUNC)
1686 policy_func_show(m, entry->func);
1687
1688 if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1689 if (entry->flags & IMA_MASK)
1690 offset = 1;
1691 if (entry->mask & MAY_EXEC)
1692 seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
1693 if (entry->mask & MAY_WRITE)
1694 seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
1695 if (entry->mask & MAY_READ)
1696 seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
1697 if (entry->mask & MAY_APPEND)
1698 seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
1699 seq_puts(m, " ");
1700 }
1701
1702 if (entry->flags & IMA_FSMAGIC) {
1703 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
1704 seq_printf(m, pt(Opt_fsmagic), tbuf);
1705 seq_puts(m, " ");
1706 }
1707
1708 if (entry->flags & IMA_FSNAME) {
1709 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
1710 seq_printf(m, pt(Opt_fsname), tbuf);
1711 seq_puts(m, " ");
1712 }
1713
1714 if (entry->flags & IMA_KEYRINGS) {
1715 seq_puts(m, "keyrings=");
1716 ima_show_rule_opt_list(m, entry->keyrings);
1717 seq_puts(m, " ");
1718 }
1719
1720 if (entry->flags & IMA_PCR) {
1721 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
1722 seq_printf(m, pt(Opt_pcr), tbuf);
1723 seq_puts(m, " ");
1724 }
1725
1726 if (entry->flags & IMA_FSUUID) {
1727 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
1728 seq_puts(m, " ");
1729 }
1730
1731 if (entry->flags & IMA_UID) {
1732 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1733 if (entry->uid_op == &uid_gt)
1734 seq_printf(m, pt(Opt_uid_gt), tbuf);
1735 else if (entry->uid_op == &uid_lt)
1736 seq_printf(m, pt(Opt_uid_lt), tbuf);
1737 else
1738 seq_printf(m, pt(Opt_uid_eq), tbuf);
1739 seq_puts(m, " ");
1740 }
1741
1742 if (entry->flags & IMA_EUID) {
1743 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1744 if (entry->uid_op == &uid_gt)
1745 seq_printf(m, pt(Opt_euid_gt), tbuf);
1746 else if (entry->uid_op == &uid_lt)
1747 seq_printf(m, pt(Opt_euid_lt), tbuf);
1748 else
1749 seq_printf(m, pt(Opt_euid_eq), tbuf);
1750 seq_puts(m, " ");
1751 }
1752
1753 if (entry->flags & IMA_FOWNER) {
1754 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
1755 if (entry->fowner_op == &uid_gt)
1756 seq_printf(m, pt(Opt_fowner_gt), tbuf);
1757 else if (entry->fowner_op == &uid_lt)
1758 seq_printf(m, pt(Opt_fowner_lt), tbuf);
1759 else
1760 seq_printf(m, pt(Opt_fowner_eq), tbuf);
1761 seq_puts(m, " ");
1762 }
1763
1764 for (i = 0; i < MAX_LSM_RULES; i++) {
1765 if (entry->lsm[i].rule) {
1766 switch (i) {
1767 case LSM_OBJ_USER:
1768 seq_printf(m, pt(Opt_obj_user),
1769 entry->lsm[i].args_p);
1770 break;
1771 case LSM_OBJ_ROLE:
1772 seq_printf(m, pt(Opt_obj_role),
1773 entry->lsm[i].args_p);
1774 break;
1775 case LSM_OBJ_TYPE:
1776 seq_printf(m, pt(Opt_obj_type),
1777 entry->lsm[i].args_p);
1778 break;
1779 case LSM_SUBJ_USER:
1780 seq_printf(m, pt(Opt_subj_user),
1781 entry->lsm[i].args_p);
1782 break;
1783 case LSM_SUBJ_ROLE:
1784 seq_printf(m, pt(Opt_subj_role),
1785 entry->lsm[i].args_p);
1786 break;
1787 case LSM_SUBJ_TYPE:
1788 seq_printf(m, pt(Opt_subj_type),
1789 entry->lsm[i].args_p);
1790 break;
1791 }
1792 seq_puts(m, " ");
1793 }
1794 }
1795 if (entry->template)
1796 seq_printf(m, "template=%s ", entry->template->name);
1797 if (entry->flags & IMA_DIGSIG_REQUIRED) {
1798 if (entry->flags & IMA_MODSIG_ALLOWED)
1799 seq_puts(m, "appraise_type=imasig|modsig ");
1800 else
1801 seq_puts(m, "appraise_type=imasig ");
1802 }
1803 if (entry->flags & IMA_CHECK_BLACKLIST)
1804 seq_puts(m, "appraise_flag=check_blacklist ");
1805 if (entry->flags & IMA_PERMIT_DIRECTIO)
1806 seq_puts(m, "permit_directio ");
1807 rcu_read_unlock();
1808 seq_puts(m, "\n");
1809 return 0;
1810 }
1811 #endif /* CONFIG_IMA_READ_POLICY */
1812
1813 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
1814 /*
1815 * ima_appraise_signature: whether IMA will appraise a given function using
1816 * an IMA digital signature. This is restricted to cases where the kernel
1817 * has a set of built-in trusted keys in order to avoid an attacker simply
1818 * loading additional keys.
1819 */
ima_appraise_signature(enum kernel_read_file_id id)1820 bool ima_appraise_signature(enum kernel_read_file_id id)
1821 {
1822 struct ima_rule_entry *entry;
1823 bool found = false;
1824 enum ima_hooks func;
1825
1826 if (id >= READING_MAX_ID)
1827 return false;
1828
1829 if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
1830 && security_locked_down(LOCKDOWN_KEXEC))
1831 return false;
1832
1833 func = read_idmap[id] ?: FILE_CHECK;
1834
1835 rcu_read_lock();
1836 list_for_each_entry_rcu(entry, ima_rules, list) {
1837 if (entry->action != APPRAISE)
1838 continue;
1839
1840 /*
1841 * A generic entry will match, but otherwise require that it
1842 * match the func we're looking for
1843 */
1844 if (entry->func && entry->func != func)
1845 continue;
1846
1847 /*
1848 * We require this to be a digital signature, not a raw IMA
1849 * hash.
1850 */
1851 if (entry->flags & IMA_DIGSIG_REQUIRED)
1852 found = true;
1853
1854 /*
1855 * We've found a rule that matches, so break now even if it
1856 * didn't require a digital signature - a later rule that does
1857 * won't override it, so would be a false positive.
1858 */
1859 break;
1860 }
1861
1862 rcu_read_unlock();
1863 return found;
1864 }
1865 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
1866