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) && rule->func != func)
 173                 return false;
 174         if ((rule->flags & IMA_MASK) && rule->mask != mask)
 175                 return false;
 176         if ((rule->flags & IMA_INMASK) &&
 177             (!(rule->mask & mask) && func != POST_SETATTR))
 178                 return false;
 179         if ((rule->flags & IMA_FSMAGIC)
 180             && rule->fsmagic != inode->i_sb->s_magic)
 181                 return false;
 182         if ((rule->flags & IMA_FSUUID) &&
 183             memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
 184                 return false;
 185         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
 186                 return false;
 187         if (rule->flags & IMA_EUID) {
 188                 if (has_capability_noaudit(current, CAP_SETUID)) {
 189                         if (!uid_eq(rule->uid, cred->euid)
 190                             && !uid_eq(rule->uid, cred->suid)
 191                             && !uid_eq(rule->uid, cred->uid))
 192                                 return false;
 193                 } else if (!uid_eq(rule->uid, cred->euid))
 194                         return false;
 195         }
 196
 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 FILE_CHECK:
 258         default:
 259                 return IMA_FILE_APPRAISE;
 260         }
 261 }
 262
 263 /**
 264  * ima_match_policy - decision based on LSM and other conditions
 265  * @inode: pointer to an inode for which the policy decision is being made
 266  * @func: IMA hook identifier
 267  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 268  *
 269  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 270  * conditions.
 271  *
 272  * (There is no need for locking when walking the policy list,
 273  * as elements in the list are never deleted, nor does the list
 274  * change.)
 275  */
 276 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 277                      int flags)
 278 {
 279         struct ima_rule_entry *entry;
 280         int action = 0, actmask = flags | (flags << 1);
 281
 282         list_for_each_entry(entry, ima_rules, list) {
 283
 284                 if (!(entry->action & actmask))
 285                         continue;
 286
 287                 if (!ima_match_rules(entry, inode, func, mask))
 288                         continue;
 289
 290                 action |= entry->flags & IMA_ACTION_FLAGS;
 291
 292                 action |= entry->action & IMA_DO_MASK;
 293                 if (entry->action & IMA_APPRAISE)
 294                         action |= get_subaction(entry, func);
 295
 296                 if (entry->action & IMA_DO_MASK)
 297                         actmask &= ~(entry->action | entry->action << 1);
 298                 else
 299                         actmask &= ~(entry->action | entry->action >> 1);
 300
 301                 if (!actmask)
 302                         break;
 303         }
 304
 305         return action;
 306 }
 307
 308 /**
 309  * ima_init_policy - initialize the default measure rules.
 310  *
 311  * ima_rules points to either the ima_default_rules or the
 312  * the new ima_policy_rules.
 313  */
 314 void __init ima_init_policy(void)
 315 {
 316         int i, measure_entries, appraise_entries;
 317
 318         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
 319         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
 320         appraise_entries = ima_use_appraise_tcb ?
 321                          ARRAY_SIZE(default_appraise_rules) : 0;
 322
 323         for (i = 0; i < measure_entries + appraise_entries; i++) {
 324                 if (i < measure_entries)
 325                         list_add_tail(&default_rules[i].list,
 326                                       &ima_default_rules);
 327                 else {
 328                         int j = i - measure_entries;
 329
 330                         list_add_tail(&default_appraise_rules[j].list,
 331                                       &ima_default_rules);
 332                 }
 333         }
 334
 335         ima_rules = &ima_default_rules;
 336 }
 337
 338 /**
 339  * ima_update_policy - update default_rules with new measure rules
 340  *
 341  * Called on file .release to update the default rules with a complete new
 342  * policy.  Once updated, the policy is locked, no additional rules can be
 343  * added to the policy.
 344  */
 345 void ima_update_policy(void)
 346 {
 347         const char *op = "policy_update";
 348         const char *cause = "already exists";
 349         int result = 1;
 350         int audit_info = 0;
 351
 352         if (ima_rules == &ima_default_rules) {
 353                 ima_rules = &ima_policy_rules;
 354                 cause = "complete";
 355                 result = 0;
 356         }
 357         integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 358                             NULL, op, cause, result, audit_info);
 359 }
 360
 361 enum {
 362         Opt_err = -1,
 363         Opt_measure = 1, Opt_dont_measure,
 364         Opt_appraise, Opt_dont_appraise,
 365         Opt_audit,
 366         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 367         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 368         Opt_func, Opt_mask, Opt_fsmagic,
 369         Opt_uid, Opt_euid, Opt_fowner,
 370         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 371 };
 372
 373 static match_table_t policy_tokens = {
 374         {Opt_measure, "measure"},
 375         {Opt_dont_measure, "dont_measure"},
 376         {Opt_appraise, "appraise"},
 377         {Opt_dont_appraise, "dont_appraise"},
 378         {Opt_audit, "audit"},
 379         {Opt_obj_user, "obj_user=%s"},
 380         {Opt_obj_role, "obj_role=%s"},
 381         {Opt_obj_type, "obj_type=%s"},
 382         {Opt_subj_user, "subj_user=%s"},
 383         {Opt_subj_role, "subj_role=%s"},
 384         {Opt_subj_type, "subj_type=%s"},
 385         {Opt_func, "func=%s"},
 386         {Opt_mask, "mask=%s"},
 387         {Opt_fsmagic, "fsmagic=%s"},
 388         {Opt_fsuuid, "fsuuid=%s"},
 389         {Opt_uid, "uid=%s"},
 390         {Opt_euid, "euid=%s"},
 391         {Opt_fowner, "fowner=%s"},
 392         {Opt_appraise_type, "appraise_type=%s"},
 393         {Opt_permit_directio, "permit_directio"},
 394         {Opt_err, NULL}
 395 };
 396
 397 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 398                              substring_t *args, int lsm_rule, int audit_type)
 399 {
 400         int result;
 401
 402         if (entry->lsm[lsm_rule].rule)
 403                 return -EINVAL;
 404
 405         entry->lsm[lsm_rule].args_p = match_strdup(args);
 406         if (!entry->lsm[lsm_rule].args_p)
 407                 return -ENOMEM;
 408
 409         entry->lsm[lsm_rule].type = audit_type;
 410         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 411                                            Audit_equal,
 412                                            entry->lsm[lsm_rule].args_p,
 413                                            &entry->lsm[lsm_rule].rule);
 414         if (!entry->lsm[lsm_rule].rule) {
 415                 kfree(entry->lsm[lsm_rule].args_p);
 416                 return -EINVAL;
 417         }
 418
 419         return result;
 420 }
 421
 422 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 423 {
 424         audit_log_format(ab, "%s=", key);
 425         audit_log_untrustedstring(ab, value);
 426         audit_log_format(ab, " ");
 427 }
 428
 429 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 430 {
 431         struct audit_buffer *ab;
 432         char *from;
 433         char *p;
 434         int result = 0;
 435
 436         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 437
 438         entry->uid = INVALID_UID;
 439         entry->fowner = INVALID_UID;
 440         entry->action = UNKNOWN;
 441         while ((p = strsep(&rule, " \t")) != NULL) {
 442                 substring_t args[MAX_OPT_ARGS];
 443                 int token;
 444                 unsigned long lnum;
 445
 446                 if (result < 0)
 447                         break;
 448                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 449                         continue;
 450                 token = match_token(p, policy_tokens, args);
 451                 switch (token) {
 452                 case Opt_measure:
 453                         ima_log_string(ab, "action", "measure");
 454
 455                         if (entry->action != UNKNOWN)
 456                                 result = -EINVAL;
 457
 458                         entry->action = MEASURE;
 459                         break;
 460                 case Opt_dont_measure:
 461                         ima_log_string(ab, "action", "dont_measure");
 462
 463                         if (entry->action != UNKNOWN)
 464                                 result = -EINVAL;
 465
 466                         entry->action = DONT_MEASURE;
 467                         break;
 468                 case Opt_appraise:
 469                         ima_log_string(ab, "action", "appraise");
 470
 471                         if (entry->action != UNKNOWN)
 472                                 result = -EINVAL;
 473
 474                         entry->action = APPRAISE;
 475                         break;
 476                 case Opt_dont_appraise:
 477                         ima_log_string(ab, "action", "dont_appraise");
 478
 479                         if (entry->action != UNKNOWN)
 480                                 result = -EINVAL;
 481
 482                         entry->action = DONT_APPRAISE;
 483                         break;
 484                 case Opt_audit:
 485                         ima_log_string(ab, "action", "audit");
 486
 487                         if (entry->action != UNKNOWN)
 488                                 result = -EINVAL;
 489
 490                         entry->action = AUDIT;
 491                         break;
 492                 case Opt_func:
 493                         ima_log_string(ab, "func", args[0].from);
 494
 495                         if (entry->func)
 496                                 result = -EINVAL;
 497
 498                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 499                                 entry->func = FILE_CHECK;
 500                         /* PATH_CHECK is for backwards compat */
 501                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 502                                 entry->func = FILE_CHECK;
 503                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 504                                 entry->func = MODULE_CHECK;
 505                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 506                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 507                                 entry->func = MMAP_CHECK;
 508                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 509                                 entry->func = BPRM_CHECK;
 510                         else
 511                                 result = -EINVAL;
 512                         if (!result)
 513                                 entry->flags |= IMA_FUNC;
 514                         break;
 515                 case Opt_mask:
 516                         ima_log_string(ab, "mask", args[0].from);
 517
 518                         if (entry->mask)
 519                                 result = -EINVAL;
 520
 521                         from = args[0].from;
 522                         if (*from == '^')
 523                                 from++;
 524
 525                         if ((strcmp(from, "MAY_EXEC")) == 0)
 526                                 entry->mask = MAY_EXEC;
 527                         else if (strcmp(from, "MAY_WRITE") == 0)
 528                                 entry->mask = MAY_WRITE;
 529                         else if (strcmp(from, "MAY_READ") == 0)
 530                                 entry->mask = MAY_READ;
 531                         else if (strcmp(from, "MAY_APPEND") == 0)
 532                                 entry->mask = MAY_APPEND;
 533                         else
 534                                 result = -EINVAL;
 535                         if (!result)
 536                                 entry->flags |= (*args[0].from == '^')
 537                                      ? IMA_INMASK : IMA_MASK;
 538                         break;
 539                 case Opt_fsmagic:
 540                         ima_log_string(ab, "fsmagic", args[0].from);
 541
 542                         if (entry->fsmagic) {
 543                                 result = -EINVAL;
 544                                 break;
 545                         }
 546
 547                         result = strict_strtoul(args[0].from, 16,
 548                                                 &entry->fsmagic);
 549                         if (!result)
 550                                 entry->flags |= IMA_FSMAGIC;
 551                         break;
 552                 case Opt_fsuuid:
 553                         ima_log_string(ab, "fsuuid", args[0].from);
 554
 555                         if (memchr_inv(entry->fsuuid, 0x00,
 556                                        sizeof(entry->fsuuid))) {
 557                                 result = -EINVAL;
 558                                 break;
 559                         }
 560
 561                         result = blk_part_pack_uuid(args[0].from,
 562                                                     entry->fsuuid);
 563                         if (!result)
 564                                 entry->flags |= IMA_FSUUID;
 565                         break;
 566                 case Opt_uid:
 567                         ima_log_string(ab, "uid", args[0].from);
 568                 case Opt_euid:
 569                         if (token == Opt_euid)
 570                                 ima_log_string(ab, "euid", args[0].from);
 571
 572                         if (uid_valid(entry->uid)) {
 573                                 result = -EINVAL;
 574                                 break;
 575                         }
 576
 577                         result = strict_strtoul(args[0].from, 10, &lnum);
 578                         if (!result) {
 579                                 entry->uid = make_kuid(current_user_ns(),
 580                                                        (uid_t) lnum);
 581                                 if (!uid_valid(entry->uid) ||
 582                                     (uid_t)lnum != lnum)
 583                                         result = -EINVAL;
 584                                 else
 585                                         entry->flags |= (token == Opt_uid)
 586                                             ? IMA_UID : IMA_EUID;
 587                         }
 588                         break;
 589                 case Opt_fowner:
 590                         ima_log_string(ab, "fowner", args[0].from);
 591
 592                         if (uid_valid(entry->fowner)) {
 593                                 result = -EINVAL;
 594                                 break;
 595                         }
 596
 597                         result = strict_strtoul(args[0].from, 10, &lnum);
 598                         if (!result) {
 599                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
 600                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
 601                                         result = -EINVAL;
 602                                 else
 603                                         entry->flags |= IMA_FOWNER;
 604                         }
 605                         break;
 606                 case Opt_obj_user:
 607                         ima_log_string(ab, "obj_user", args[0].from);
 608                         result = ima_lsm_rule_init(entry, args,
 609                                                    LSM_OBJ_USER,
 610                                                    AUDIT_OBJ_USER);
 611                         break;
 612                 case Opt_obj_role:
 613                         ima_log_string(ab, "obj_role", args[0].from);
 614                         result = ima_lsm_rule_init(entry, args,
 615                                                    LSM_OBJ_ROLE,
 616                                                    AUDIT_OBJ_ROLE);
 617                         break;
 618                 case Opt_obj_type:
 619                         ima_log_string(ab, "obj_type", args[0].from);
 620                         result = ima_lsm_rule_init(entry, args,
 621                                                    LSM_OBJ_TYPE,
 622                                                    AUDIT_OBJ_TYPE);
 623                         break;
 624                 case Opt_subj_user:
 625                         ima_log_string(ab, "subj_user", args[0].from);
 626                         result = ima_lsm_rule_init(entry, args,
 627                                                    LSM_SUBJ_USER,
 628                                                    AUDIT_SUBJ_USER);
 629                         break;
 630                 case Opt_subj_role:
 631                         ima_log_string(ab, "subj_role", args[0].from);
 632                         result = ima_lsm_rule_init(entry, args,
 633                                                    LSM_SUBJ_ROLE,
 634                                                    AUDIT_SUBJ_ROLE);
 635                         break;
 636                 case Opt_subj_type:
 637                         ima_log_string(ab, "subj_type", args[0].from);
 638                         result = ima_lsm_rule_init(entry, args,
 639                                                    LSM_SUBJ_TYPE,
 640                                                    AUDIT_SUBJ_TYPE);
 641                         break;
 642                 case Opt_appraise_type:
 643                         if (entry->action != APPRAISE) {
 644                                 result = -EINVAL;
 645                                 break;
 646                         }
 647
 648                         ima_log_string(ab, "appraise_type", args[0].from);
 649                         if ((strcmp(args[0].from, "imasig")) == 0)
 650                                 entry->flags |= IMA_DIGSIG_REQUIRED;
 651                         else
 652                                 result = -EINVAL;
 653                         break;
 654                 case Opt_permit_directio:
 655                         entry->flags |= IMA_PERMIT_DIRECTIO;
 656                         break;
 657                 case Opt_err:
 658                         ima_log_string(ab, "UNKNOWN", p);
 659                         result = -EINVAL;
 660                         break;
 661                 }
 662         }
 663         if (!result && (entry->action == UNKNOWN))
 664                 result = -EINVAL;
 665         else if (entry->func == MODULE_CHECK)
 666                 ima_appraise |= IMA_APPRAISE_MODULES;
 667         audit_log_format(ab, "res=%d", !result);
 668         audit_log_end(ab);
 669         return result;
 670 }
 671
 672 /**
 673  * ima_parse_add_rule - add a rule to ima_policy_rules
 674  * @rule - ima measurement policy rule
 675  *
 676  * Uses a mutex to protect the policy list from multiple concurrent writers.
 677  * Returns the length of the rule parsed, an error code on failure
 678  */
 679 ssize_t ima_parse_add_rule(char *rule)
 680 {
 681         const char *op = "update_policy";
 682         char *p;
 683         struct ima_rule_entry *entry;
 684         ssize_t result, len;
 685         int audit_info = 0;
 686
 687         /* Prevent installed policy from changing */
 688         if (ima_rules != &ima_default_rules) {
 689                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 690                                     NULL, op, "already exists",
 691                                     -EACCES, audit_info);
 692                 return -EACCES;
 693         }
 694
 695         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 696         if (!entry) {
 697                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 698                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 699                 return -ENOMEM;
 700         }
 701
 702         INIT_LIST_HEAD(&entry->list);
 703
 704         p = strsep(&rule, "\n");
 705         len = strlen(p) + 1;
 706
 707         if (*p == '#') {
 708                 kfree(entry);
 709                 return len;
 710         }
 711
 712         result = ima_parse_rule(p, entry);
 713         if (result) {
 714                 kfree(entry);
 715                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 716                                     NULL, op, "invalid policy", result,
 717                                     audit_info);
 718                 return result;
 719         }
 720
 721         mutex_lock(&ima_rules_mutex);
 722         list_add_tail(&entry->list, &ima_policy_rules);
 723         mutex_unlock(&ima_rules_mutex);
 724
 725         return len;
 726 }
 727
 728 /* ima_delete_rules called to cleanup invalid policy */
 729 void ima_delete_rules(void)
 730 {
 731         struct ima_rule_entry *entry, *tmp;
 732         int i;
 733
 734         mutex_lock(&ima_rules_mutex);
 735         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 736                 for (i = 0; i < MAX_LSM_RULES; i++)
 737                         kfree(entry->lsm[i].args_p);
 738
 739                 list_del(&entry->list);
 740                 kfree(entry);
 741         }
 742         mutex_unlock(&ima_rules_mutex);
 743 }