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 int ima_policy_flag;
  39
  40 #define MAX_LSM_RULES 6
  41 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  42         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  43 };
  44
  45 struct ima_rule_entry {
  46         struct list_head list;
  47         int action;
  48         unsigned int flags;
  49         enum ima_hooks func;
  50         int mask;
  51         unsigned long fsmagic;
  52         u8 fsuuid[16];
  53         kuid_t uid;
  54         kuid_t fowner;
  55         struct {
  56                 void *rule;     /* LSM file metadata specific */
  57                 void *args_p;   /* audit value */
  58                 int type;       /* audit type */
  59         } lsm[MAX_LSM_RULES];
  60 };
  61
  62 /*
  63  * Without LSM specific knowledge, the default policy can only be
  64  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  65  */
  66
  67 /*
  68  * The minimum rule set to allow for full TCB coverage.  Measures all files
  69  * opened or mmap for exec and everything read by root.  Dangerous because
  70  * normal users can easily run the machine out of memory simply building
  71  * and running executables.
  72  */
  73 static struct ima_rule_entry default_rules[] = {
  74         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  75         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  76         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  77         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  78         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  79         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  80         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  81         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  82         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
  83          .flags = IMA_FSMAGIC},
  84         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
  85         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
  86          .flags = IMA_FUNC | IMA_MASK},
  87         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
  88          .flags = IMA_FUNC | IMA_MASK},
  89         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID,
  90          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
  91         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  92         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
  93 };
  94
  95 static struct ima_rule_entry default_appraise_rules[] = {
  96         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  97         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  98         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  99         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 100         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 101         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 102         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 103         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 104         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 105         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 106         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 107 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 108         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 109 #else
 110         /* force signature */
 111         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
 112          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 113 #endif
 114 };
 115
 116 static LIST_HEAD(ima_default_rules);
 117 static LIST_HEAD(ima_policy_rules);
 118 static struct list_head *ima_rules;
 119
 120 static DEFINE_MUTEX(ima_rules_mutex);
 121
 122 static bool ima_use_tcb __initdata;
 123 static int __init default_measure_policy_setup(char *str)
 124 {
 125         ima_use_tcb = 1;
 126         return 1;
 127 }
 128 __setup("ima_tcb", default_measure_policy_setup);
 129
 130 static bool ima_use_appraise_tcb __initdata;
 131 static int __init default_appraise_policy_setup(char *str)
 132 {
 133         ima_use_appraise_tcb = 1;
 134         return 1;
 135 }
 136 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 137
 138 /*
 139  * Although the IMA policy does not change, the LSM policy can be
 140  * reloaded, leaving the IMA LSM based rules referring to the old,
 141  * stale LSM policy.
 142  *
 143  * Update the IMA LSM based rules to reflect the reloaded LSM policy.
 144  * We assume the rules still exist; and BUG_ON() if they don't.
 145  */
 146 static void ima_lsm_update_rules(void)
 147 {
 148         struct ima_rule_entry *entry, *tmp;
 149         int result;
 150         int i;
 151
 152         mutex_lock(&ima_rules_mutex);
 153         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 154                 for (i = 0; i < MAX_LSM_RULES; i++) {
 155                         if (!entry->lsm[i].rule)
 156                                 continue;
 157                         result = security_filter_rule_init(entry->lsm[i].type,
 158                                                            Audit_equal,
 159                                                            entry->lsm[i].args_p,
 160                                                            &entry->lsm[i].rule);
 161                         BUG_ON(!entry->lsm[i].rule);
 162                 }
 163         }
 164         mutex_unlock(&ima_rules_mutex);
 165 }
 166
 167 /**
 168  * ima_match_rules - determine whether an inode matches the measure rule.
 169  * @rule: a pointer to a rule
 170  * @inode: a pointer to an inode
 171  * @func: LIM hook identifier
 172  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 173  *
 174  * Returns true on rule match, false on failure.
 175  */
 176 static bool ima_match_rules(struct ima_rule_entry *rule,
 177                             struct inode *inode, enum ima_hooks func, int mask)
 178 {
 179         struct task_struct *tsk = current;
 180         const struct cred *cred = current_cred();
 181         int i;
 182
 183         if ((rule->flags & IMA_FUNC) &&
 184             (rule->func != func && func != POST_SETATTR))
 185                 return false;
 186         if ((rule->flags & IMA_MASK) &&
 187             (rule->mask != mask && func != POST_SETATTR))
 188                 return false;
 189         if ((rule->flags & IMA_FSMAGIC)
 190             && rule->fsmagic != inode->i_sb->s_magic)
 191                 return false;
 192         if ((rule->flags & IMA_FSUUID) &&
 193             memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
 194                 return false;
 195         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
 196                 return false;
 197         if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
 198                 return false;
 199         for (i = 0; i < MAX_LSM_RULES; i++) {
 200                 int rc = 0;
 201                 u32 osid, sid;
 202                 int retried = 0;
 203
 204                 if (!rule->lsm[i].rule)
 205                         continue;
 206 retry:
 207                 switch (i) {
 208                 case LSM_OBJ_USER:
 209                 case LSM_OBJ_ROLE:
 210                 case LSM_OBJ_TYPE:
 211                         security_inode_getsecid(inode, &osid);
 212                         rc = security_filter_rule_match(osid,
 213                                                         rule->lsm[i].type,
 214                                                         Audit_equal,
 215                                                         rule->lsm[i].rule,
 216                                                         NULL);
 217                         break;
 218                 case LSM_SUBJ_USER:
 219                 case LSM_SUBJ_ROLE:
 220                 case LSM_SUBJ_TYPE:
 221                         security_task_getsecid(tsk, &sid);
 222                         rc = security_filter_rule_match(sid,
 223                                                         rule->lsm[i].type,
 224                                                         Audit_equal,
 225                                                         rule->lsm[i].rule,
 226                                                         NULL);
 227                 default:
 228                         break;
 229                 }
 230                 if ((rc < 0) && (!retried)) {
 231                         retried = 1;
 232                         ima_lsm_update_rules();
 233                         goto retry;
 234                 }
 235                 if (!rc)
 236                         return false;
 237         }
 238         return true;
 239 }
 240
 241 /*
 242  * In addition to knowing that we need to appraise the file in general,
 243  * we need to differentiate between calling hooks, for hook specific rules.
 244  */
 245 static int get_subaction(struct ima_rule_entry *rule, int func)
 246 {
 247         if (!(rule->flags & IMA_FUNC))
 248                 return IMA_FILE_APPRAISE;
 249
 250         switch (func) {
 251         case MMAP_CHECK:
 252                 return IMA_MMAP_APPRAISE;
 253         case BPRM_CHECK:
 254                 return IMA_BPRM_APPRAISE;
 255         case MODULE_CHECK:
 256                 return IMA_MODULE_APPRAISE;
 257         case FIRMWARE_CHECK:
 258                 return IMA_FIRMWARE_APPRAISE;
 259         case FILE_CHECK:
 260         default:
 261                 return IMA_FILE_APPRAISE;
 262         }
 263 }
 264
 265 /**
 266  * ima_match_policy - decision based on LSM and other conditions
 267  * @inode: pointer to an inode for which the policy decision is being made
 268  * @func: IMA hook identifier
 269  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 270  *
 271  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 272  * conditions.
 273  *
 274  * (There is no need for locking when walking the policy list,
 275  * as elements in the list are never deleted, nor does the list
 276  * change.)
 277  */
 278 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 279                      int flags)
 280 {
 281         struct ima_rule_entry *entry;
 282         int action = 0, actmask = flags | (flags << 1);
 283
 284         list_for_each_entry(entry, ima_rules, list) {
 285
 286                 if (!(entry->action & actmask))
 287                         continue;
 288
 289                 if (!ima_match_rules(entry, inode, func, mask))
 290                         continue;
 291
 292                 action |= entry->flags & IMA_ACTION_FLAGS;
 293
 294                 action |= entry->action & IMA_DO_MASK;
 295                 if (entry->action & IMA_APPRAISE)
 296                         action |= get_subaction(entry, func);
 297
 298                 if (entry->action & IMA_DO_MASK)
 299                         actmask &= ~(entry->action | entry->action << 1);
 300                 else
 301                         actmask &= ~(entry->action | entry->action >> 1);
 302
 303                 if (!actmask)
 304                         break;
 305         }
 306
 307         return action;
 308 }
 309
 310 /*
 311  * Initialize the ima_policy_flag variable based on the currently
 312  * loaded policy.  Based on this flag, the decision to short circuit
 313  * out of a function or not call the function in the first place
 314  * can be made earlier.
 315  */
 316 void ima_update_policy_flag(void)
 317 {
 318         struct ima_rule_entry *entry;
 319
 320         ima_policy_flag = 0;
 321         list_for_each_entry(entry, ima_rules, list) {
 322                 if (entry->action & IMA_DO_MASK)
 323                         ima_policy_flag |= entry->action;
 324         }
 325
 326         if (!ima_appraise)
 327                 ima_policy_flag &= ~IMA_APPRAISE;
 328 }
 329
 330 /**
 331  * ima_init_policy - initialize the default measure rules.
 332  *
 333  * ima_rules points to either the ima_default_rules or the
 334  * the new ima_policy_rules.
 335  */
 336 void __init ima_init_policy(void)
 337 {
 338         int i, measure_entries, appraise_entries;
 339
 340         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
 341         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
 342         appraise_entries = ima_use_appraise_tcb ?
 343                          ARRAY_SIZE(default_appraise_rules) : 0;
 344
 345         for (i = 0; i < measure_entries; i++)
 346                 list_add_tail(&default_rules[i].list, &ima_default_rules);
 347
 348         for (i = 0; i < appraise_entries; i++) {
 349                 list_add_tail(&default_appraise_rules[i].list,
 350                               &ima_default_rules);
 351         }
 352
 353         ima_rules = &ima_default_rules;
 354 }
 355
 356 /**
 357  * ima_update_policy - update default_rules with new measure rules
 358  *
 359  * Called on file .release to update the default rules with a complete new
 360  * policy.  Once updated, the policy is locked, no additional rules can be
 361  * added to the policy.
 362  */
 363 void ima_update_policy(void)
 364 {
 365         ima_rules = &ima_policy_rules;
 366         ima_update_policy_flag();
 367 }
 368
 369 enum {
 370         Opt_err = -1,
 371         Opt_measure = 1, Opt_dont_measure,
 372         Opt_appraise, Opt_dont_appraise,
 373         Opt_audit,
 374         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 375         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 376         Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
 377         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 378 };
 379
 380 static match_table_t policy_tokens = {
 381         {Opt_measure, "measure"},
 382         {Opt_dont_measure, "dont_measure"},
 383         {Opt_appraise, "appraise"},
 384         {Opt_dont_appraise, "dont_appraise"},
 385         {Opt_audit, "audit"},
 386         {Opt_obj_user, "obj_user=%s"},
 387         {Opt_obj_role, "obj_role=%s"},
 388         {Opt_obj_type, "obj_type=%s"},
 389         {Opt_subj_user, "subj_user=%s"},
 390         {Opt_subj_role, "subj_role=%s"},
 391         {Opt_subj_type, "subj_type=%s"},
 392         {Opt_func, "func=%s"},
 393         {Opt_mask, "mask=%s"},
 394         {Opt_fsmagic, "fsmagic=%s"},
 395         {Opt_fsuuid, "fsuuid=%s"},
 396         {Opt_uid, "uid=%s"},
 397         {Opt_fowner, "fowner=%s"},
 398         {Opt_appraise_type, "appraise_type=%s"},
 399         {Opt_permit_directio, "permit_directio"},
 400         {Opt_err, NULL}
 401 };
 402
 403 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 404                              substring_t *args, int lsm_rule, int audit_type)
 405 {
 406         int result;
 407
 408         if (entry->lsm[lsm_rule].rule)
 409                 return -EINVAL;
 410
 411         entry->lsm[lsm_rule].args_p = match_strdup(args);
 412         if (!entry->lsm[lsm_rule].args_p)
 413                 return -ENOMEM;
 414
 415         entry->lsm[lsm_rule].type = audit_type;
 416         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 417                                            Audit_equal,
 418                                            entry->lsm[lsm_rule].args_p,
 419                                            &entry->lsm[lsm_rule].rule);
 420         if (!entry->lsm[lsm_rule].rule) {
 421                 kfree(entry->lsm[lsm_rule].args_p);
 422                 return -EINVAL;
 423         }
 424
 425         return result;
 426 }
 427
 428 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 429 {
 430         audit_log_format(ab, "%s=", key);
 431         audit_log_untrustedstring(ab, value);
 432         audit_log_format(ab, " ");
 433 }
 434
 435 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 436 {
 437         struct audit_buffer *ab;
 438         char *p;
 439         int result = 0;
 440
 441         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 442
 443         entry->uid = INVALID_UID;
 444         entry->fowner = INVALID_UID;
 445         entry->action = UNKNOWN;
 446         while ((p = strsep(&rule, " \t")) != NULL) {
 447                 substring_t args[MAX_OPT_ARGS];
 448                 int token;
 449                 unsigned long lnum;
 450
 451                 if (result < 0)
 452                         break;
 453                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 454                         continue;
 455                 token = match_token(p, policy_tokens, args);
 456                 switch (token) {
 457                 case Opt_measure:
 458                         ima_log_string(ab, "action", "measure");
 459
 460                         if (entry->action != UNKNOWN)
 461                                 result = -EINVAL;
 462
 463                         entry->action = MEASURE;
 464                         break;
 465                 case Opt_dont_measure:
 466                         ima_log_string(ab, "action", "dont_measure");
 467
 468                         if (entry->action != UNKNOWN)
 469                                 result = -EINVAL;
 470
 471                         entry->action = DONT_MEASURE;
 472                         break;
 473                 case Opt_appraise:
 474                         ima_log_string(ab, "action", "appraise");
 475
 476                         if (entry->action != UNKNOWN)
 477                                 result = -EINVAL;
 478
 479                         entry->action = APPRAISE;
 480                         break;
 481                 case Opt_dont_appraise:
 482                         ima_log_string(ab, "action", "dont_appraise");
 483
 484                         if (entry->action != UNKNOWN)
 485                                 result = -EINVAL;
 486
 487                         entry->action = DONT_APPRAISE;
 488                         break;
 489                 case Opt_audit:
 490                         ima_log_string(ab, "action", "audit");
 491
 492                         if (entry->action != UNKNOWN)
 493                                 result = -EINVAL;
 494
 495                         entry->action = AUDIT;
 496                         break;
 497                 case Opt_func:
 498                         ima_log_string(ab, "func", args[0].from);
 499
 500                         if (entry->func)
 501                                 result = -EINVAL;
 502
 503                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 504                                 entry->func = FILE_CHECK;
 505                         /* PATH_CHECK is for backwards compat */
 506                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 507                                 entry->func = FILE_CHECK;
 508                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 509                                 entry->func = MODULE_CHECK;
 510                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
 511                                 entry->func = FIRMWARE_CHECK;
 512                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 513                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 514                                 entry->func = MMAP_CHECK;
 515                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 516                                 entry->func = BPRM_CHECK;
 517                         else
 518                                 result = -EINVAL;
 519                         if (!result)
 520                                 entry->flags |= IMA_FUNC;
 521                         break;
 522                 case Opt_mask:
 523                         ima_log_string(ab, "mask", args[0].from);
 524
 525                         if (entry->mask)
 526                                 result = -EINVAL;
 527
 528                         if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
 529                                 entry->mask = MAY_EXEC;
 530                         else if (strcmp(args[0].from, "MAY_WRITE") == 0)
 531                                 entry->mask = MAY_WRITE;
 532                         else if (strcmp(args[0].from, "MAY_READ") == 0)
 533                                 entry->mask = MAY_READ;
 534                         else if (strcmp(args[0].from, "MAY_APPEND") == 0)
 535                                 entry->mask = MAY_APPEND;
 536                         else
 537                                 result = -EINVAL;
 538                         if (!result)
 539                                 entry->flags |= IMA_MASK;
 540                         break;
 541                 case Opt_fsmagic:
 542                         ima_log_string(ab, "fsmagic", args[0].from);
 543
 544                         if (entry->fsmagic) {
 545                                 result = -EINVAL;
 546                                 break;
 547                         }
 548
 549                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
 550                         if (!result)
 551                                 entry->flags |= IMA_FSMAGIC;
 552                         break;
 553                 case Opt_fsuuid:
 554                         ima_log_string(ab, "fsuuid", args[0].from);
 555
 556                         if (memchr_inv(entry->fsuuid, 0x00,
 557                                        sizeof(entry->fsuuid))) {
 558                                 result = -EINVAL;
 559                                 break;
 560                         }
 561
 562                         result = blk_part_pack_uuid(args[0].from,
 563                                                     entry->fsuuid);
 564                         if (!result)
 565                                 entry->flags |= IMA_FSUUID;
 566                         break;
 567                 case Opt_uid:
 568                         ima_log_string(ab, "uid", args[0].from);
 569
 570                         if (uid_valid(entry->uid)) {
 571                                 result = -EINVAL;
 572                                 break;
 573                         }
 574
 575                         result = kstrtoul(args[0].from, 10, &lnum);
 576                         if (!result) {
 577                                 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
 578                                 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
 579                                         result = -EINVAL;
 580                                 else
 581                                         entry->flags |= IMA_UID;
 582                         }
 583                         break;
 584                 case Opt_fowner:
 585                         ima_log_string(ab, "fowner", args[0].from);
 586
 587                         if (uid_valid(entry->fowner)) {
 588                                 result = -EINVAL;
 589                                 break;
 590                         }
 591
 592                         result = kstrtoul(args[0].from, 10, &lnum);
 593                         if (!result) {
 594                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
 595                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
 596                                         result = -EINVAL;
 597                                 else
 598                                         entry->flags |= IMA_FOWNER;
 599                         }
 600                         break;
 601                 case Opt_obj_user:
 602                         ima_log_string(ab, "obj_user", args[0].from);
 603                         result = ima_lsm_rule_init(entry, args,
 604                                                    LSM_OBJ_USER,
 605                                                    AUDIT_OBJ_USER);
 606                         break;
 607                 case Opt_obj_role:
 608                         ima_log_string(ab, "obj_role", args[0].from);
 609                         result = ima_lsm_rule_init(entry, args,
 610                                                    LSM_OBJ_ROLE,
 611                                                    AUDIT_OBJ_ROLE);
 612                         break;
 613                 case Opt_obj_type:
 614                         ima_log_string(ab, "obj_type", args[0].from);
 615                         result = ima_lsm_rule_init(entry, args,
 616                                                    LSM_OBJ_TYPE,
 617                                                    AUDIT_OBJ_TYPE);
 618                         break;
 619                 case Opt_subj_user:
 620                         ima_log_string(ab, "subj_user", args[0].from);
 621                         result = ima_lsm_rule_init(entry, args,
 622                                                    LSM_SUBJ_USER,
 623                                                    AUDIT_SUBJ_USER);
 624                         break;
 625                 case Opt_subj_role:
 626                         ima_log_string(ab, "subj_role", args[0].from);
 627                         result = ima_lsm_rule_init(entry, args,
 628                                                    LSM_SUBJ_ROLE,
 629                                                    AUDIT_SUBJ_ROLE);
 630                         break;
 631                 case Opt_subj_type:
 632                         ima_log_string(ab, "subj_type", args[0].from);
 633                         result = ima_lsm_rule_init(entry, args,
 634                                                    LSM_SUBJ_TYPE,
 635                                                    AUDIT_SUBJ_TYPE);
 636                         break;
 637                 case Opt_appraise_type:
 638                         if (entry->action != APPRAISE) {
 639                                 result = -EINVAL;
 640                                 break;
 641                         }
 642
 643                         ima_log_string(ab, "appraise_type", args[0].from);
 644                         if ((strcmp(args[0].from, "imasig")) == 0)
 645                                 entry->flags |= IMA_DIGSIG_REQUIRED;
 646                         else
 647                                 result = -EINVAL;
 648                         break;
 649                 case Opt_permit_directio:
 650                         entry->flags |= IMA_PERMIT_DIRECTIO;
 651                         break;
 652                 case Opt_err:
 653                         ima_log_string(ab, "UNKNOWN", p);
 654                         result = -EINVAL;
 655                         break;
 656                 }
 657         }
 658         if (!result && (entry->action == UNKNOWN))
 659                 result = -EINVAL;
 660         else if (entry->func == MODULE_CHECK)
 661                 ima_appraise |= IMA_APPRAISE_MODULES;
 662         else if (entry->func == FIRMWARE_CHECK)
 663                 ima_appraise |= IMA_APPRAISE_FIRMWARE;
 664         audit_log_format(ab, "res=%d", !result);
 665         audit_log_end(ab);
 666         return result;
 667 }
 668
 669 /**
 670  * ima_parse_add_rule - add a rule to ima_policy_rules
 671  * @rule - ima measurement policy rule
 672  *
 673  * Uses a mutex to protect the policy list from multiple concurrent writers.
 674  * Returns the length of the rule parsed, an error code on failure
 675  */
 676 ssize_t ima_parse_add_rule(char *rule)
 677 {
 678         static const char op[] = "update_policy";
 679         char *p;
 680         struct ima_rule_entry *entry;
 681         ssize_t result, len;
 682         int audit_info = 0;
 683
 684         p = strsep(&rule, "\n");
 685         len = strlen(p) + 1;
 686         p += strspn(p, " \t");
 687
 688         if (*p == '#' || *p == '\0')
 689                 return len;
 690
 691         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 692         if (!entry) {
 693                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 694                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 695                 return -ENOMEM;
 696         }
 697
 698         INIT_LIST_HEAD(&entry->list);
 699
 700         result = ima_parse_rule(p, entry);
 701         if (result) {
 702                 kfree(entry);
 703                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 704                                     NULL, op, "invalid-policy", result,
 705                                     audit_info);
 706                 return result;
 707         }
 708
 709         mutex_lock(&ima_rules_mutex);
 710         list_add_tail(&entry->list, &ima_policy_rules);
 711         mutex_unlock(&ima_rules_mutex);
 712
 713         return len;
 714 }
 715
 716 /* ima_delete_rules called to cleanup invalid policy */
 717 void ima_delete_rules(void)
 718 {
 719         struct ima_rule_entry *entry, *tmp;
 720         int i;
 721
 722         mutex_lock(&ima_rules_mutex);
 723         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 724                 for (i = 0; i < MAX_LSM_RULES; i++)
 725                         kfree(entry->lsm[i].args_p);
 726
 727                 list_del(&entry->list);
 728                 kfree(entry);
 729         }
 730         mutex_unlock(&ima_rules_mutex);
 731 }