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 #define IMA_INMASK      0x0040
  31 #define IMA_EUID        0x0080
  32
  33 #define UNKNOWN         0
  34 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  35 #define DONT_MEASURE    0x0002
  36 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  37 #define DONT_APPRAISE   0x0008
  38 #define AUDIT           0x0040
  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 = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
  83          .flags = IMA_FUNC | IMA_MASK},
  84         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
  85          .flags = IMA_FUNC | IMA_MASK},
  86         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID,
  87          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
  88         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  89 };
  90
  91 static struct ima_rule_entry default_appraise_rules[] = {
  92         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  93         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  94         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  95         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  96         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
  97         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  98         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  99         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 100         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 101         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 102         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 103 };
 104
 105 static LIST_HEAD(ima_default_rules);
 106 static LIST_HEAD(ima_policy_rules);
 107 static struct list_head *ima_rules;
 108
 109 static DEFINE_MUTEX(ima_rules_mutex);
 110
 111 static bool ima_use_tcb __initdata;
 112 static int __init default_measure_policy_setup(char *str)
 113 {
 114         ima_use_tcb = 1;
 115         return 1;
 116 }
 117 __setup("ima_tcb", default_measure_policy_setup);
 118
 119 static bool ima_use_appraise_tcb __initdata;
 120 static int __init default_appraise_policy_setup(char *str)
 121 {
 122         ima_use_appraise_tcb = 1;
 123         return 1;
 124 }
 125 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 126
 127 /*
 128  * Although the IMA policy does not change, the LSM policy can be
 129  * reloaded, leaving the IMA LSM based rules referring to the old,
 130  * stale LSM policy.
 131  *
 132  * Update the IMA LSM based rules to reflect the reloaded LSM policy.
 133  * We assume the rules still exist; and BUG_ON() if they don't.
 134  */
 135 static void ima_lsm_update_rules(void)
 136 {
 137         struct ima_rule_entry *entry, *tmp;
 138         int result;
 139         int i;
 140
 141         mutex_lock(&ima_rules_mutex);
 142         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 143                 for (i = 0; i < MAX_LSM_RULES; i++) {
 144                         if (!entry->lsm[i].rule)
 145                                 continue;
 146                         result = security_filter_rule_init(entry->lsm[i].type,
 147                                                            Audit_equal,
 148                                                            entry->lsm[i].args_p,
 149                                                            &entry->lsm[i].rule);
 150                         BUG_ON(!entry->lsm[i].rule);
 151                 }
 152         }
 153         mutex_unlock(&ima_rules_mutex);
 154 }
 155
 156 /**
 157  * ima_match_rules - determine whether an inode matches the measure rule.
 158  * @rule: a pointer to a rule
 159  * @inode: a pointer to an inode
 160  * @func: LIM hook identifier
 161  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 162  *
 163  * Returns true on rule match, false on failure.
 164  */
 165 static bool ima_match_rules(struct ima_rule_entry *rule,
 166                             struct inode *inode, enum ima_hooks func, int mask)
 167 {
 168         struct task_struct *tsk = current;
 169         const struct cred *cred = current_cred();
 170         int i;
 171
 172         if ((rule->flags & IMA_FUNC) &&
 173             (rule->func != func && func != POST_SETATTR))
 174                 return false;
 175         if ((rule->flags & IMA_MASK) &&
 176             (rule->mask != mask && func != POST_SETATTR))
 177                 return false;
 178         if ((rule->flags & IMA_INMASK) &&
 179             (!(rule->mask & mask) && func != POST_SETATTR))
 180                 return false;
 181         if ((rule->flags & IMA_FSMAGIC)
 182             && rule->fsmagic != inode->i_sb->s_magic)
 183                 return false;
 184         if ((rule->flags & IMA_FSUUID) &&
 185             memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
 186                 return false;
 187         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
 188                 return false;
 189         if (rule->flags & IMA_EUID) {
 190                 if (has_capability_noaudit(current, CAP_SETUID)) {
 191                         if (!uid_eq(rule->uid, cred->euid)
 192                             && !uid_eq(rule->uid, cred->suid)
 193                             && !uid_eq(rule->uid, cred->uid))
 194                                 return false;
 195                 } else if (!uid_eq(rule->uid, cred->euid))
 196                         return false;
 197         }
 198
 199         if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
 200                 return false;
 201         for (i = 0; i < MAX_LSM_RULES; i++) {
 202                 int rc = 0;
 203                 u32 osid, sid;
 204                 int retried = 0;
 205
 206                 if (!rule->lsm[i].rule)
 207                         continue;
 208 retry:
 209                 switch (i) {
 210                 case LSM_OBJ_USER:
 211                 case LSM_OBJ_ROLE:
 212                 case LSM_OBJ_TYPE:
 213                         security_inode_getsecid(inode, &osid);
 214                         rc = security_filter_rule_match(osid,
 215                                                         rule->lsm[i].type,
 216                                                         Audit_equal,
 217                                                         rule->lsm[i].rule,
 218                                                         NULL);
 219                         break;
 220                 case LSM_SUBJ_USER:
 221                 case LSM_SUBJ_ROLE:
 222                 case LSM_SUBJ_TYPE:
 223                         security_task_getsecid(tsk, &sid);
 224                         rc = security_filter_rule_match(sid,
 225                                                         rule->lsm[i].type,
 226                                                         Audit_equal,
 227                                                         rule->lsm[i].rule,
 228                                                         NULL);
 229                 default:
 230                         break;
 231                 }
 232                 if ((rc < 0) && (!retried)) {
 233                         retried = 1;
 234                         ima_lsm_update_rules();
 235                         goto retry;
 236                 }
 237                 if (!rc)
 238                         return false;
 239         }
 240         return true;
 241 }
 242
 243 /*
 244  * In addition to knowing that we need to appraise the file in general,
 245  * we need to differentiate between calling hooks, for hook specific rules.
 246  */
 247 static int get_subaction(struct ima_rule_entry *rule, int func)
 248 {
 249         if (!(rule->flags & IMA_FUNC))
 250                 return IMA_FILE_APPRAISE;
 251
 252         switch (func) {
 253         case MMAP_CHECK:
 254                 return IMA_MMAP_APPRAISE;
 255         case BPRM_CHECK:
 256                 return IMA_BPRM_APPRAISE;
 257         case MODULE_CHECK:
 258                 return IMA_MODULE_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  * ima_init_policy - initialize the default measure rules.
 312  *
 313  * ima_rules points to either the ima_default_rules or the
 314  * the new ima_policy_rules.
 315  */
 316 void __init ima_init_policy(void)
 317 {
 318         int i, measure_entries, appraise_entries;
 319
 320         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
 321         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
 322         appraise_entries = ima_use_appraise_tcb ?
 323                          ARRAY_SIZE(default_appraise_rules) : 0;
 324
 325         for (i = 0; i < measure_entries + appraise_entries; i++) {
 326                 if (i < measure_entries)
 327                         list_add_tail(&default_rules[i].list,
 328                                       &ima_default_rules);
 329                 else {
 330                         int j = i - measure_entries;
 331
 332                         list_add_tail(&default_appraise_rules[j].list,
 333                                       &ima_default_rules);
 334                 }
 335         }
 336
 337         ima_rules = &ima_default_rules;
 338 }
 339
 340 /**
 341  * ima_update_policy - update default_rules with new measure rules
 342  *
 343  * Called on file .release to update the default rules with a complete new
 344  * policy.  Once updated, the policy is locked, no additional rules can be
 345  * added to the policy.
 346  */
 347 void ima_update_policy(void)
 348 {
 349         static const char op[] = "policy_update";
 350         const char *cause = "already exists";
 351         int result = 1;
 352         int audit_info = 0;
 353
 354         if (ima_rules == &ima_default_rules) {
 355                 ima_rules = &ima_policy_rules;
 356                 cause = "complete";
 357                 result = 0;
 358         }
 359         integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 360                             NULL, op, cause, result, audit_info);
 361 }
 362
 363 enum {
 364         Opt_err = -1,
 365         Opt_measure = 1, Opt_dont_measure,
 366         Opt_appraise, Opt_dont_appraise,
 367         Opt_audit,
 368         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 369         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 370         Opt_func, Opt_mask, Opt_fsmagic,
 371         Opt_uid, Opt_euid, Opt_fowner,
 372         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 373 };
 374
 375 static match_table_t policy_tokens = {
 376         {Opt_measure, "measure"},
 377         {Opt_dont_measure, "dont_measure"},
 378         {Opt_appraise, "appraise"},
 379         {Opt_dont_appraise, "dont_appraise"},
 380         {Opt_audit, "audit"},
 381         {Opt_obj_user, "obj_user=%s"},
 382         {Opt_obj_role, "obj_role=%s"},
 383         {Opt_obj_type, "obj_type=%s"},
 384         {Opt_subj_user, "subj_user=%s"},
 385         {Opt_subj_role, "subj_role=%s"},
 386         {Opt_subj_type, "subj_type=%s"},
 387         {Opt_func, "func=%s"},
 388         {Opt_mask, "mask=%s"},
 389         {Opt_fsmagic, "fsmagic=%s"},
 390         {Opt_fsuuid, "fsuuid=%s"},
 391         {Opt_uid, "uid=%s"},
 392         {Opt_euid, "euid=%s"},
 393         {Opt_fowner, "fowner=%s"},
 394         {Opt_appraise_type, "appraise_type=%s"},
 395         {Opt_permit_directio, "permit_directio"},
 396         {Opt_err, NULL}
 397 };
 398
 399 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 400                              substring_t *args, int lsm_rule, int audit_type)
 401 {
 402         int result;
 403
 404         if (entry->lsm[lsm_rule].rule)
 405                 return -EINVAL;
 406
 407         entry->lsm[lsm_rule].args_p = match_strdup(args);
 408         if (!entry->lsm[lsm_rule].args_p)
 409                 return -ENOMEM;
 410
 411         entry->lsm[lsm_rule].type = audit_type;
 412         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 413                                            Audit_equal,
 414                                            entry->lsm[lsm_rule].args_p,
 415                                            &entry->lsm[lsm_rule].rule);
 416         if (!entry->lsm[lsm_rule].rule) {
 417                 kfree(entry->lsm[lsm_rule].args_p);
 418                 return -EINVAL;
 419         }
 420
 421         return result;
 422 }
 423
 424 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 425 {
 426         audit_log_format(ab, "%s=", key);
 427         audit_log_untrustedstring(ab, value);
 428         audit_log_format(ab, " ");
 429 }
 430
 431 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 432 {
 433         struct audit_buffer *ab;
 434         char *from;
 435         char *p;
 436         int result = 0;
 437
 438         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 439
 440         entry->uid = INVALID_UID;
 441         entry->fowner = INVALID_UID;
 442         entry->action = UNKNOWN;
 443         while ((p = strsep(&rule, " \t")) != NULL) {
 444                 substring_t args[MAX_OPT_ARGS];
 445                 int token;
 446                 unsigned long lnum;
 447
 448                 if (result < 0)
 449                         break;
 450                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 451                         continue;
 452                 token = match_token(p, policy_tokens, args);
 453                 switch (token) {
 454                 case Opt_measure:
 455                         ima_log_string(ab, "action", "measure");
 456
 457                         if (entry->action != UNKNOWN)
 458                                 result = -EINVAL;
 459
 460                         entry->action = MEASURE;
 461                         break;
 462                 case Opt_dont_measure:
 463                         ima_log_string(ab, "action", "dont_measure");
 464
 465                         if (entry->action != UNKNOWN)
 466                                 result = -EINVAL;
 467
 468                         entry->action = DONT_MEASURE;
 469                         break;
 470                 case Opt_appraise:
 471                         ima_log_string(ab, "action", "appraise");
 472
 473                         if (entry->action != UNKNOWN)
 474                                 result = -EINVAL;
 475
 476                         entry->action = APPRAISE;
 477                         break;
 478                 case Opt_dont_appraise:
 479                         ima_log_string(ab, "action", "dont_appraise");
 480
 481                         if (entry->action != UNKNOWN)
 482                                 result = -EINVAL;
 483
 484                         entry->action = DONT_APPRAISE;
 485                         break;
 486                 case Opt_audit:
 487                         ima_log_string(ab, "action", "audit");
 488
 489                         if (entry->action != UNKNOWN)
 490                                 result = -EINVAL;
 491
 492                         entry->action = AUDIT;
 493                         break;
 494                 case Opt_func:
 495                         ima_log_string(ab, "func", args[0].from);
 496
 497                         if (entry->func)
 498                                 result = -EINVAL;
 499
 500                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 501                                 entry->func = FILE_CHECK;
 502                         /* PATH_CHECK is for backwards compat */
 503                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 504                                 entry->func = FILE_CHECK;
 505                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 506                                 entry->func = MODULE_CHECK;
 507                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 508                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 509                                 entry->func = MMAP_CHECK;
 510                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 511                                 entry->func = BPRM_CHECK;
 512                         else
 513                                 result = -EINVAL;
 514                         if (!result)
 515                                 entry->flags |= IMA_FUNC;
 516                         break;
 517                 case Opt_mask:
 518                         ima_log_string(ab, "mask", args[0].from);
 519
 520                         if (entry->mask)
 521                                 result = -EINVAL;
 522
 523                         from = args[0].from;
 524                         if (*from == '^')
 525                                 from++;
 526
 527                         if ((strcmp(from, "MAY_EXEC")) == 0)
 528                                 entry->mask = MAY_EXEC;
 529                         else if (strcmp(from, "MAY_WRITE") == 0)
 530                                 entry->mask = MAY_WRITE;
 531                         else if (strcmp(from, "MAY_READ") == 0)
 532                                 entry->mask = MAY_READ;
 533                         else if (strcmp(from, "MAY_APPEND") == 0)
 534                                 entry->mask = MAY_APPEND;
 535                         else
 536                                 result = -EINVAL;
 537                         if (!result)
 538                                 entry->flags |= (*args[0].from == '^')
 539                                      ? IMA_INMASK : 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                 case Opt_euid:
 570                         if (token == Opt_euid)
 571                                 ima_log_string(ab, "euid", args[0].from);
 572
 573                         if (uid_valid(entry->uid)) {
 574                                 result = -EINVAL;
 575                                 break;
 576                         }
 577
 578                         result = kstrtoul(args[0].from, 10, &lnum);
 579                         if (!result) {
 580                                 entry->uid = make_kuid(current_user_ns(),
 581                                                        (uid_t) lnum);
 582                                 if (!uid_valid(entry->uid) ||
 583                                     (uid_t)lnum != lnum)
 584                                         result = -EINVAL;
 585                                 else
 586                                         entry->flags |= (token == Opt_uid)
 587                                             ? IMA_UID : IMA_EUID;
 588                         }
 589                         break;
 590                 case Opt_fowner:
 591                         ima_log_string(ab, "fowner", args[0].from);
 592
 593                         if (uid_valid(entry->fowner)) {
 594                                 result = -EINVAL;
 595                                 break;
 596                         }
 597
 598                         result = kstrtoul(args[0].from, 10, &lnum);
 599                         if (!result) {
 600                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
 601                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
 602                                         result = -EINVAL;
 603                                 else
 604                                         entry->flags |= IMA_FOWNER;
 605                         }
 606                         break;
 607                 case Opt_obj_user:
 608                         ima_log_string(ab, "obj_user", args[0].from);
 609                         result = ima_lsm_rule_init(entry, args,
 610                                                    LSM_OBJ_USER,
 611                                                    AUDIT_OBJ_USER);
 612                         break;
 613                 case Opt_obj_role:
 614                         ima_log_string(ab, "obj_role", args[0].from);
 615                         result = ima_lsm_rule_init(entry, args,
 616                                                    LSM_OBJ_ROLE,
 617                                                    AUDIT_OBJ_ROLE);
 618                         break;
 619                 case Opt_obj_type:
 620                         ima_log_string(ab, "obj_type", args[0].from);
 621                         result = ima_lsm_rule_init(entry, args,
 622                                                    LSM_OBJ_TYPE,
 623                                                    AUDIT_OBJ_TYPE);
 624                         break;
 625                 case Opt_subj_user:
 626                         ima_log_string(ab, "subj_user", args[0].from);
 627                         result = ima_lsm_rule_init(entry, args,
 628                                                    LSM_SUBJ_USER,
 629                                                    AUDIT_SUBJ_USER);
 630                         break;
 631                 case Opt_subj_role:
 632                         ima_log_string(ab, "subj_role", args[0].from);
 633                         result = ima_lsm_rule_init(entry, args,
 634                                                    LSM_SUBJ_ROLE,
 635                                                    AUDIT_SUBJ_ROLE);
 636                         break;
 637                 case Opt_subj_type:
 638                         ima_log_string(ab, "subj_type", args[0].from);
 639                         result = ima_lsm_rule_init(entry, args,
 640                                                    LSM_SUBJ_TYPE,
 641                                                    AUDIT_SUBJ_TYPE);
 642                         break;
 643                 case Opt_appraise_type:
 644                         if (entry->action != APPRAISE) {
 645                                 result = -EINVAL;
 646                                 break;
 647                         }
 648
 649                         ima_log_string(ab, "appraise_type", args[0].from);
 650                         if ((strcmp(args[0].from, "imasig")) == 0)
 651                                 entry->flags |= IMA_DIGSIG_REQUIRED;
 652                         else
 653                                 result = -EINVAL;
 654                         break;
 655                 case Opt_permit_directio:
 656                         entry->flags |= IMA_PERMIT_DIRECTIO;
 657                         break;
 658                 case Opt_err:
 659                         ima_log_string(ab, "UNKNOWN", p);
 660                         result = -EINVAL;
 661                         break;
 662                 }
 663         }
 664         if (!result && (entry->action == UNKNOWN))
 665                 result = -EINVAL;
 666         else if (entry->func == MODULE_CHECK)
 667                 ima_appraise |= IMA_APPRAISE_MODULES;
 668         audit_log_format(ab, "res=%d", !result);
 669         audit_log_end(ab);
 670         return result;
 671 }
 672
 673 /**
 674  * ima_parse_add_rule - add a rule to ima_policy_rules
 675  * @rule - ima measurement policy rule
 676  *
 677  * Uses a mutex to protect the policy list from multiple concurrent writers.
 678  * Returns the length of the rule parsed, an error code on failure
 679  */
 680 ssize_t ima_parse_add_rule(char *rule)
 681 {
 682         static const char op[] = "update_policy";
 683         char *p;
 684         struct ima_rule_entry *entry;
 685         ssize_t result, len;
 686         int audit_info = 0;
 687
 688         /* Prevent installed policy from changing */
 689         if (ima_rules != &ima_default_rules) {
 690                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 691                                     NULL, op, "already exists",
 692                                     -EACCES, audit_info);
 693                 return -EACCES;
 694         }
 695
 696         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 697         if (!entry) {
 698                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 699                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 700                 return -ENOMEM;
 701         }
 702
 703         INIT_LIST_HEAD(&entry->list);
 704
 705         p = strsep(&rule, "\n");
 706         len = strlen(p) + 1;
 707
 708         if (*p == '#') {
 709                 kfree(entry);
 710                 return len;
 711         }
 712
 713         result = ima_parse_rule(p, entry);
 714         if (result) {
 715                 kfree(entry);
 716                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 717                                     NULL, op, "invalid policy", result,
 718                                     audit_info);
 719                 return result;
 720         }
 721
 722         mutex_lock(&ima_rules_mutex);
 723         list_add_tail(&entry->list, &ima_policy_rules);
 724         mutex_unlock(&ima_rules_mutex);
 725
 726         return len;
 727 }
 728
 729 /* ima_delete_rules called to cleanup invalid policy */
 730 void ima_delete_rules(void)
 731 {
 732         struct ima_rule_entry *entry, *tmp;
 733         int i;
 734
 735         mutex_lock(&ima_rules_mutex);
 736         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 737                 for (i = 0; i < MAX_LSM_RULES; i++)
 738                         kfree(entry->lsm[i].args_p);
 739
 740                 list_del(&entry->list);
 741                 kfree(entry);
 742         }
 743         mutex_unlock(&ima_rules_mutex);
 744 }