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