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