ima: rename hash calculation functions
[linux-3.10.git] / security / integrity / ima / ima_policy.c
1 /*
2  * Copyright (C) 2008 IBM Corporation
3  * Author: Mimi Zohar <zohar@us.ibm.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation, version 2 of the License.
8  *
9  * ima_policy.c
10  *      - initialize default measure policy rules
11  *
12  */
13 #include <linux/module.h>
14 #include <linux/list.h>
15 #include <linux/security.h>
16 #include <linux/magic.h>
17 #include <linux/parser.h>
18 #include <linux/slab.h>
19 #include <linux/genhd.h>
20
21 #include "ima.h"
22
23 /* flags definitions */
24 #define IMA_FUNC        0x0001
25 #define IMA_MASK        0x0002
26 #define IMA_FSMAGIC     0x0004
27 #define IMA_UID         0x0008
28 #define IMA_FOWNER      0x0010
29 #define IMA_FSUUID      0x0020
30
31 #define UNKNOWN         0
32 #define MEASURE         0x0001  /* same as IMA_MEASURE */
33 #define DONT_MEASURE    0x0002
34 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
35 #define DONT_APPRAISE   0x0008
36 #define AUDIT           0x0040
37
38 #define MAX_LSM_RULES 6
39 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
40         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
41 };
42
43 struct ima_rule_entry {
44         struct list_head list;
45         int action;
46         unsigned int flags;
47         enum ima_hooks func;
48         int mask;
49         unsigned long fsmagic;
50         u8 fsuuid[16];
51         kuid_t uid;
52         kuid_t fowner;
53         struct {
54                 void *rule;     /* LSM file metadata specific */
55                 void *args_p;   /* audit value */
56                 int type;       /* audit type */
57         } lsm[MAX_LSM_RULES];
58 };
59
60 /*
61  * Without LSM specific knowledge, the default policy can only be
62  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
63  */
64
65 /*
66  * The minimum rule set to allow for full TCB coverage.  Measures all files
67  * opened or mmap for exec and everything read by root.  Dangerous because
68  * normal users can easily run the machine out of memory simply building
69  * and running executables.
70  */
71 static struct ima_rule_entry default_rules[] = {
72         {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
73         {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
74         {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
75         {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
76         {.action = DONT_MEASURE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC},
77         {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC},
78         {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC},
79         {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
80         {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
81         {.action = MEASURE,.func = MMAP_CHECK,.mask = MAY_EXEC,
82          .flags = IMA_FUNC | IMA_MASK},
83         {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
84          .flags = IMA_FUNC | IMA_MASK},
85         {.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID,
86          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
87         {.action = MEASURE,.func = MODULE_CHECK, .flags = IMA_FUNC},
88 };
89
90 static struct ima_rule_entry default_appraise_rules[] = {
91         {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
92         {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
93         {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
94         {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
95         {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC},
96         {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC},
97         {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC},
98         {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
99         {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
100         {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC},
101         {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER},
102 };
103
104 static LIST_HEAD(ima_default_rules);
105 static LIST_HEAD(ima_policy_rules);
106 static struct list_head *ima_rules;
107
108 static DEFINE_MUTEX(ima_rules_mutex);
109
110 static bool ima_use_tcb __initdata;
111 static int __init default_measure_policy_setup(char *str)
112 {
113         ima_use_tcb = 1;
114         return 1;
115 }
116 __setup("ima_tcb", default_measure_policy_setup);
117
118 static bool ima_use_appraise_tcb __initdata;
119 static int __init default_appraise_policy_setup(char *str)
120 {
121         ima_use_appraise_tcb = 1;
122         return 1;
123 }
124 __setup("ima_appraise_tcb", default_appraise_policy_setup);
125
126 /* 
127  * Although the IMA policy does not change, the LSM policy can be
128  * reloaded, leaving the IMA LSM based rules referring to the old,
129  * stale LSM policy.
130  *
131  * Update the IMA LSM based rules to reflect the reloaded LSM policy. 
132  * We assume the rules still exist; and BUG_ON() if they don't.
133  */
134 static void ima_lsm_update_rules(void)
135 {
136         struct ima_rule_entry *entry, *tmp;
137         int result;
138         int i;
139
140         mutex_lock(&ima_rules_mutex);
141         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
142                 for (i = 0; i < MAX_LSM_RULES; i++) {
143                         if (!entry->lsm[i].rule)
144                                 continue;
145                         result = security_filter_rule_init(entry->lsm[i].type,
146                                                            Audit_equal,
147                                                            entry->lsm[i].args_p,
148                                                            &entry->lsm[i].rule);
149                         BUG_ON(!entry->lsm[i].rule);
150                 }
151         }
152         mutex_unlock(&ima_rules_mutex);
153 }
154
155 /**
156  * ima_match_rules - determine whether an inode matches the measure rule.
157  * @rule: a pointer to a rule
158  * @inode: a pointer to an inode
159  * @func: LIM hook identifier
160  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
161  *
162  * Returns true on rule match, false on failure.
163  */
164 static bool ima_match_rules(struct ima_rule_entry *rule,
165                             struct inode *inode, enum ima_hooks func, int mask)
166 {
167         struct task_struct *tsk = current;
168         const struct cred *cred = current_cred();
169         int i;
170
171         if ((rule->flags & IMA_FUNC) && rule->func != func)
172                 return false;
173         if ((rule->flags & IMA_MASK) && rule->mask != mask)
174                 return false;
175         if ((rule->flags & IMA_FSMAGIC)
176             && rule->fsmagic != inode->i_sb->s_magic)
177                 return false;
178         if ((rule->flags & IMA_FSUUID) &&
179                 memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
180                 return false;
181         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
182                 return false;
183         if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
184                 return false;
185         for (i = 0; i < MAX_LSM_RULES; i++) {
186                 int rc = 0;
187                 u32 osid, sid;
188                 int retried = 0;
189
190                 if (!rule->lsm[i].rule)
191                         continue;
192 retry:
193                 switch (i) {
194                 case LSM_OBJ_USER:
195                 case LSM_OBJ_ROLE:
196                 case LSM_OBJ_TYPE:
197                         security_inode_getsecid(inode, &osid);
198                         rc = security_filter_rule_match(osid,
199                                                         rule->lsm[i].type,
200                                                         Audit_equal,
201                                                         rule->lsm[i].rule,
202                                                         NULL);
203                         break;
204                 case LSM_SUBJ_USER:
205                 case LSM_SUBJ_ROLE:
206                 case LSM_SUBJ_TYPE:
207                         security_task_getsecid(tsk, &sid);
208                         rc = security_filter_rule_match(sid,
209                                                         rule->lsm[i].type,
210                                                         Audit_equal,
211                                                         rule->lsm[i].rule,
212                                                         NULL);
213                 default:
214                         break;
215                 }
216                 if ((rc < 0) && (!retried)) {
217                         retried = 1;
218                         ima_lsm_update_rules();
219                         goto retry;
220                 } 
221                 if (!rc)
222                         return false;
223         }
224         return true;
225 }
226
227 /*
228  * In addition to knowing that we need to appraise the file in general,
229  * we need to differentiate between calling hooks, for hook specific rules.
230  */
231 static int get_subaction(struct ima_rule_entry *rule, int func)
232 {
233         if (!(rule->flags & IMA_FUNC))
234                 return IMA_FILE_APPRAISE;
235
236         switch(func) {
237         case MMAP_CHECK:
238                 return IMA_MMAP_APPRAISE;
239         case BPRM_CHECK:
240                 return IMA_BPRM_APPRAISE;
241         case MODULE_CHECK:
242                 return IMA_MODULE_APPRAISE;
243         case FILE_CHECK:
244         default:
245                 return IMA_FILE_APPRAISE;
246         }
247 }
248
249 /**
250  * ima_match_policy - decision based on LSM and other conditions
251  * @inode: pointer to an inode for which the policy decision is being made
252  * @func: IMA hook identifier
253  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
254  *
255  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
256  * conditions.
257  *
258  * (There is no need for locking when walking the policy list,
259  * as elements in the list are never deleted, nor does the list
260  * change.)
261  */
262 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
263                      int flags)
264 {
265         struct ima_rule_entry *entry;
266         int action = 0, actmask = flags | (flags << 1);
267
268         list_for_each_entry(entry, ima_rules, list) {
269
270                 if (!(entry->action & actmask))
271                         continue;
272
273                 if (!ima_match_rules(entry, inode, func, mask))
274                         continue;
275
276                 action |= entry->flags & IMA_ACTION_FLAGS;
277
278                 action |= entry->action & IMA_DO_MASK;
279                 if (entry->action & IMA_APPRAISE)
280                         action |= get_subaction(entry, func);
281
282                 if (entry->action & IMA_DO_MASK)
283                         actmask &= ~(entry->action | entry->action << 1);
284                 else
285                         actmask &= ~(entry->action | entry->action >> 1);
286
287                 if (!actmask)
288                         break;
289         }
290
291         return action;
292 }
293
294 /**
295  * ima_init_policy - initialize the default measure rules.
296  *
297  * ima_rules points to either the ima_default_rules or the
298  * the new ima_policy_rules.
299  */
300 void __init ima_init_policy(void)
301 {
302         int i, measure_entries, appraise_entries;
303
304         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
305         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
306         appraise_entries = ima_use_appraise_tcb ?
307                          ARRAY_SIZE(default_appraise_rules) : 0;
308         
309         for (i = 0; i < measure_entries + appraise_entries; i++) {
310                 if (i < measure_entries)
311                         list_add_tail(&default_rules[i].list,
312                                       &ima_default_rules);
313                 else {
314                         int j = i - measure_entries;
315
316                         list_add_tail(&default_appraise_rules[j].list,
317                                       &ima_default_rules);
318                 }
319         }
320
321         ima_rules = &ima_default_rules;
322 }
323
324 /**
325  * ima_update_policy - update default_rules with new measure rules
326  *
327  * Called on file .release to update the default rules with a complete new
328  * policy.  Once updated, the policy is locked, no additional rules can be
329  * added to the policy.
330  */
331 void ima_update_policy(void)
332 {
333         const char *op = "policy_update";
334         const char *cause = "already exists";
335         int result = 1;
336         int audit_info = 0;
337
338         if (ima_rules == &ima_default_rules) {
339                 ima_rules = &ima_policy_rules;
340                 cause = "complete";
341                 result = 0;
342         }
343         integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
344                             NULL, op, cause, result, audit_info);
345 }
346
347 enum {
348         Opt_err = -1,
349         Opt_measure = 1, Opt_dont_measure,
350         Opt_appraise, Opt_dont_appraise,
351         Opt_audit,
352         Opt_obj_user, Opt_obj_role, Opt_obj_type,
353         Opt_subj_user, Opt_subj_role, Opt_subj_type,
354         Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
355         Opt_appraise_type, Opt_fsuuid
356 };
357
358 static match_table_t policy_tokens = {
359         {Opt_measure, "measure"},
360         {Opt_dont_measure, "dont_measure"},
361         {Opt_appraise, "appraise"},
362         {Opt_dont_appraise, "dont_appraise"},
363         {Opt_audit, "audit"},
364         {Opt_obj_user, "obj_user=%s"},
365         {Opt_obj_role, "obj_role=%s"},
366         {Opt_obj_type, "obj_type=%s"},
367         {Opt_subj_user, "subj_user=%s"},
368         {Opt_subj_role, "subj_role=%s"},
369         {Opt_subj_type, "subj_type=%s"},
370         {Opt_func, "func=%s"},
371         {Opt_mask, "mask=%s"},
372         {Opt_fsmagic, "fsmagic=%s"},
373         {Opt_fsuuid, "fsuuid=%s"},
374         {Opt_uid, "uid=%s"},
375         {Opt_fowner, "fowner=%s"},
376         {Opt_appraise_type, "appraise_type=%s"},
377         {Opt_err, NULL}
378 };
379
380 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
381                              substring_t *args, int lsm_rule, int audit_type)
382 {
383         int result;
384
385         if (entry->lsm[lsm_rule].rule)
386                 return -EINVAL;
387
388         entry->lsm[lsm_rule].args_p = match_strdup(args);
389         if (!entry->lsm[lsm_rule].args_p)
390                 return -ENOMEM;
391
392         entry->lsm[lsm_rule].type = audit_type;
393         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
394                                            Audit_equal,
395                                            entry->lsm[lsm_rule].args_p,
396                                            &entry->lsm[lsm_rule].rule);
397         if (!entry->lsm[lsm_rule].rule) {
398                 kfree(entry->lsm[lsm_rule].args_p);
399                 return -EINVAL;
400         }
401
402         return result;
403 }
404
405 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
406 {
407         audit_log_format(ab, "%s=", key);
408         audit_log_untrustedstring(ab, value);
409         audit_log_format(ab, " ");
410 }
411
412 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
413 {
414         struct audit_buffer *ab;
415         char *p;
416         int result = 0;
417
418         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
419
420         entry->uid = INVALID_UID;
421         entry->fowner = INVALID_UID;
422         entry->action = UNKNOWN;
423         while ((p = strsep(&rule, " \t")) != NULL) {
424                 substring_t args[MAX_OPT_ARGS];
425                 int token;
426                 unsigned long lnum;
427
428                 if (result < 0)
429                         break;
430                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
431                         continue;
432                 token = match_token(p, policy_tokens, args);
433                 switch (token) {
434                 case Opt_measure:
435                         ima_log_string(ab, "action", "measure");
436
437                         if (entry->action != UNKNOWN)
438                                 result = -EINVAL;
439
440                         entry->action = MEASURE;
441                         break;
442                 case Opt_dont_measure:
443                         ima_log_string(ab, "action", "dont_measure");
444
445                         if (entry->action != UNKNOWN)
446                                 result = -EINVAL;
447
448                         entry->action = DONT_MEASURE;
449                         break;
450                 case Opt_appraise:
451                         ima_log_string(ab, "action", "appraise");
452
453                         if (entry->action != UNKNOWN)
454                                 result = -EINVAL;
455
456                         entry->action = APPRAISE;
457                         break;
458                 case Opt_dont_appraise:
459                         ima_log_string(ab, "action", "dont_appraise");
460
461                         if (entry->action != UNKNOWN)
462                                 result = -EINVAL;
463
464                         entry->action = DONT_APPRAISE;
465                         break;
466                 case Opt_audit:
467                         ima_log_string(ab, "action", "audit");
468
469                         if (entry->action != UNKNOWN)
470                                 result = -EINVAL;
471
472                         entry->action = AUDIT;
473                         break;
474                 case Opt_func:
475                         ima_log_string(ab, "func", args[0].from);
476
477                         if (entry->func)
478                                 result = -EINVAL;
479
480                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
481                                 entry->func = FILE_CHECK;
482                         /* PATH_CHECK is for backwards compat */
483                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
484                                 entry->func = FILE_CHECK;
485                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
486                                 entry->func = MODULE_CHECK;
487                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
488                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
489                                 entry->func = MMAP_CHECK;
490                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
491                                 entry->func = BPRM_CHECK;
492                         else
493                                 result = -EINVAL;
494                         if (!result)
495                                 entry->flags |= IMA_FUNC;
496                         break;
497                 case Opt_mask:
498                         ima_log_string(ab, "mask", args[0].from);
499
500                         if (entry->mask)
501                                 result = -EINVAL;
502
503                         if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
504                                 entry->mask = MAY_EXEC;
505                         else if (strcmp(args[0].from, "MAY_WRITE") == 0)
506                                 entry->mask = MAY_WRITE;
507                         else if (strcmp(args[0].from, "MAY_READ") == 0)
508                                 entry->mask = MAY_READ;
509                         else if (strcmp(args[0].from, "MAY_APPEND") == 0)
510                                 entry->mask = MAY_APPEND;
511                         else
512                                 result = -EINVAL;
513                         if (!result)
514                                 entry->flags |= IMA_MASK;
515                         break;
516                 case Opt_fsmagic:
517                         ima_log_string(ab, "fsmagic", args[0].from);
518
519                         if (entry->fsmagic) {
520                                 result = -EINVAL;
521                                 break;
522                         }
523
524                         result = strict_strtoul(args[0].from, 16,
525                                                 &entry->fsmagic);
526                         if (!result)
527                                 entry->flags |= IMA_FSMAGIC;
528                         break;
529                 case Opt_fsuuid:
530                         ima_log_string(ab, "fsuuid", args[0].from);
531
532                         if (memchr_inv(entry->fsuuid, 0x00,
533                             sizeof(entry->fsuuid))) {
534                                 result = -EINVAL;
535                                 break;
536                         }
537
538                         part_pack_uuid(args[0].from, entry->fsuuid);
539                         entry->flags |= IMA_FSUUID;
540                         result = 0;
541                         break;
542                 case Opt_uid:
543                         ima_log_string(ab, "uid", args[0].from);
544
545                         if (uid_valid(entry->uid)) {
546                                 result = -EINVAL;
547                                 break;
548                         }
549
550                         result = strict_strtoul(args[0].from, 10, &lnum);
551                         if (!result) {
552                                 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
553                                 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
554                                         result = -EINVAL;
555                                 else
556                                         entry->flags |= IMA_UID;
557                         }
558                         break;
559                 case Opt_fowner:
560                         ima_log_string(ab, "fowner", args[0].from);
561
562                         if (uid_valid(entry->fowner)) {
563                                 result = -EINVAL;
564                                 break;
565                         }
566
567                         result = strict_strtoul(args[0].from, 10, &lnum);
568                         if (!result) {
569                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
570                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
571                                         result = -EINVAL;
572                                 else
573                                         entry->flags |= IMA_FOWNER;
574                         }
575                         break;
576                 case Opt_obj_user:
577                         ima_log_string(ab, "obj_user", args[0].from);
578                         result = ima_lsm_rule_init(entry, args,
579                                                    LSM_OBJ_USER,
580                                                    AUDIT_OBJ_USER);
581                         break;
582                 case Opt_obj_role:
583                         ima_log_string(ab, "obj_role", args[0].from);
584                         result = ima_lsm_rule_init(entry, args,
585                                                    LSM_OBJ_ROLE,
586                                                    AUDIT_OBJ_ROLE);
587                         break;
588                 case Opt_obj_type:
589                         ima_log_string(ab, "obj_type", args[0].from);
590                         result = ima_lsm_rule_init(entry, args,
591                                                    LSM_OBJ_TYPE,
592                                                    AUDIT_OBJ_TYPE);
593                         break;
594                 case Opt_subj_user:
595                         ima_log_string(ab, "subj_user", args[0].from);
596                         result = ima_lsm_rule_init(entry, args,
597                                                    LSM_SUBJ_USER,
598                                                    AUDIT_SUBJ_USER);
599                         break;
600                 case Opt_subj_role:
601                         ima_log_string(ab, "subj_role", args[0].from);
602                         result = ima_lsm_rule_init(entry, args,
603                                                    LSM_SUBJ_ROLE,
604                                                    AUDIT_SUBJ_ROLE);
605                         break;
606                 case Opt_subj_type:
607                         ima_log_string(ab, "subj_type", args[0].from);
608                         result = ima_lsm_rule_init(entry, args,
609                                                    LSM_SUBJ_TYPE,
610                                                    AUDIT_SUBJ_TYPE);
611                         break;
612                 case Opt_appraise_type:
613                         if (entry->action != APPRAISE) {
614                                 result = -EINVAL;
615                                 break;
616                         }
617
618                         ima_log_string(ab, "appraise_type", args[0].from);
619                         if ((strcmp(args[0].from, "imasig")) == 0)
620                                 entry->flags |= IMA_DIGSIG_REQUIRED;
621                         else
622                                 result = -EINVAL;
623                         break;
624                 case Opt_err:
625                         ima_log_string(ab, "UNKNOWN", p);
626                         result = -EINVAL;
627                         break;
628                 }
629         }
630         if (!result && (entry->action == UNKNOWN))
631                 result = -EINVAL;
632
633         audit_log_format(ab, "res=%d", !result);
634         audit_log_end(ab);
635         return result;
636 }
637
638 /**
639  * ima_parse_add_rule - add a rule to ima_policy_rules
640  * @rule - ima measurement policy rule
641  *
642  * Uses a mutex to protect the policy list from multiple concurrent writers.
643  * Returns the length of the rule parsed, an error code on failure
644  */
645 ssize_t ima_parse_add_rule(char *rule)
646 {
647         const char *op = "update_policy";
648         char *p;
649         struct ima_rule_entry *entry;
650         ssize_t result, len;
651         int audit_info = 0;
652
653         /* Prevent installed policy from changing */
654         if (ima_rules != &ima_default_rules) {
655                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
656                                     NULL, op, "already exists",
657                                     -EACCES, audit_info);
658                 return -EACCES;
659         }
660
661         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
662         if (!entry) {
663                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
664                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
665                 return -ENOMEM;
666         }
667
668         INIT_LIST_HEAD(&entry->list);
669
670         p = strsep(&rule, "\n");
671         len = strlen(p) + 1;
672
673         if (*p == '#') {
674                 kfree(entry);
675                 return len;
676         }
677
678         result = ima_parse_rule(p, entry);
679         if (result) {
680                 kfree(entry);
681                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
682                                     NULL, op, "invalid policy", result,
683                                     audit_info);
684                 return result;
685         }
686
687         mutex_lock(&ima_rules_mutex);
688         list_add_tail(&entry->list, &ima_policy_rules);
689         mutex_unlock(&ima_rules_mutex);
690
691         return len;
692 }
693
694 /* ima_delete_rules called to cleanup invalid policy */
695 void ima_delete_rules(void)
696 {
697         struct ima_rule_entry *entry, *tmp;
698         int i;
699
700         mutex_lock(&ima_rules_mutex);
701         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
702                 for (i = 0; i < MAX_LSM_RULES; i++)
703                         kfree(entry->lsm[i].args_p);
704
705                 list_del(&entry->list);
706                 kfree(entry);
707         }
708         mutex_unlock(&ima_rules_mutex);
709 }