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 int ima_policy_flag;
  41
  42 #define MAX_LSM_RULES 6
  43 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  44         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  45 };
  46
  47 struct ima_rule_entry {
  48         struct list_head list;
  49         int action;
  50         unsigned int flags;
  51         enum ima_hooks func;
  52         int mask;
  53         unsigned long fsmagic;
  54         u8 fsuuid[16];
  55         kuid_t uid;
  56         kuid_t fowner;
  57         struct {
  58                 void *rule;     /* LSM file metadata specific */
  59                 void *args_p;   /* audit value */
  60                 int type;       /* audit type */
  61         } lsm[MAX_LSM_RULES];
  62 };
  63
  64 /*
  65  * Without LSM specific knowledge, the default policy can only be
  66  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  67  */
  68
  69 /*
  70  * The minimum rule set to allow for full TCB coverage.  Measures all files
  71  * opened or mmap for exec and everything read by root.  Dangerous because
  72  * normal users can easily run the machine out of memory simply building
  73  * and running executables.
  74  */
  75 static struct ima_rule_entry default_rules[] = {
  76         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  77         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  78         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  79         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  80         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  81         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  82         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  83         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  84         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
  85          .flags = IMA_FSMAGIC},
  86         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
  87         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
  88          .flags = IMA_FUNC | IMA_MASK},
  89         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
  90          .flags = IMA_FUNC | IMA_MASK},
  91         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID,
  92          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
  93         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  94         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
  95 };
  96
  97 static struct ima_rule_entry default_appraise_rules[] = {
  98         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  99         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 100         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 101         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 102         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 103         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 104         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 105         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 106         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 107         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 108         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 109 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 110         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 111 #else
 112         /* force signature */
 113         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
 114          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 115 #endif
 116 };
 117
 118 static LIST_HEAD(ima_default_rules);
 119 static LIST_HEAD(ima_policy_rules);
 120 static struct list_head *ima_rules;
 121
 122 static DEFINE_MUTEX(ima_rules_mutex);
 123
 124 static bool ima_use_tcb __initdata;
 125 static int __init default_measure_policy_setup(char *str)
 126 {
 127         ima_use_tcb = 1;
 128         return 1;
 129 }
 130 __setup("ima_tcb", default_measure_policy_setup);
 131
 132 static bool ima_use_appraise_tcb __initdata;
 133 static int __init default_appraise_policy_setup(char *str)
 134 {
 135         ima_use_appraise_tcb = 1;
 136         return 1;
 137 }
 138 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 139
 140 /*
 141  * Although the IMA policy does not change, the LSM policy can be
 142  * reloaded, leaving the IMA LSM based rules referring to the old,
 143  * stale LSM policy.
 144  *
 145  * Update the IMA LSM based rules to reflect the reloaded LSM policy.
 146  * We assume the rules still exist; and BUG_ON() if they don't.
 147  */
 148 static void ima_lsm_update_rules(void)
 149 {
 150         struct ima_rule_entry *entry, *tmp;
 151         int result;
 152         int i;
 153
 154         mutex_lock(&ima_rules_mutex);
 155         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 156                 for (i = 0; i < MAX_LSM_RULES; i++) {
 157                         if (!entry->lsm[i].rule)
 158                                 continue;
 159                         result = security_filter_rule_init(entry->lsm[i].type,
 160                                                            Audit_equal,
 161                                                            entry->lsm[i].args_p,
 162                                                            &entry->lsm[i].rule);
 163                         BUG_ON(!entry->lsm[i].rule);
 164                 }
 165         }
 166         mutex_unlock(&ima_rules_mutex);
 167 }
 168
 169 /**
 170  * ima_match_rules - determine whether an inode matches the measure rule.
 171  * @rule: a pointer to a rule
 172  * @inode: a pointer to an inode
 173  * @func: LIM hook identifier
 174  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 175  *
 176  * Returns true on rule match, false on failure.
 177  */
 178 static bool ima_match_rules(struct ima_rule_entry *rule,
 179                             struct inode *inode, enum ima_hooks func, int mask)
 180 {
 181         struct task_struct *tsk = current;
 182         const struct cred *cred = current_cred();
 183         int i;
 184
 185         if ((rule->flags & IMA_FUNC) &&
 186             (rule->func != func && func != POST_SETATTR))
 187                 return false;
 188         if ((rule->flags & IMA_MASK) &&
 189             (rule->mask != mask && func != POST_SETATTR))
 190                 return false;
 191         if ((rule->flags & IMA_INMASK) &&
 192             (!(rule->mask & mask) && func != POST_SETATTR))
 193                 return false;
 194         if ((rule->flags & IMA_FSMAGIC)
 195             && rule->fsmagic != inode->i_sb->s_magic)
 196                 return false;
 197         if ((rule->flags & IMA_FSUUID) &&
 198             memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
 199                 return false;
 200         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
 201                 return false;
 202         if (rule->flags & IMA_EUID) {
 203                 if (has_capability_noaudit(current, CAP_SETUID)) {
 204                         if (!uid_eq(rule->uid, cred->euid)
 205                             && !uid_eq(rule->uid, cred->suid)
 206                             && !uid_eq(rule->uid, cred->uid))
 207                                 return false;
 208                 } else if (!uid_eq(rule->uid, cred->euid))
 209                         return false;
 210         }
 211
 212         if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
 213                 return false;
 214         for (i = 0; i < MAX_LSM_RULES; i++) {
 215                 int rc = 0;
 216                 u32 osid, sid;
 217                 int retried = 0;
 218
 219                 if (!rule->lsm[i].rule)
 220                         continue;
 221 retry:
 222                 switch (i) {
 223                 case LSM_OBJ_USER:
 224                 case LSM_OBJ_ROLE:
 225                 case LSM_OBJ_TYPE:
 226                         security_inode_getsecid(inode, &osid);
 227                         rc = security_filter_rule_match(osid,
 228                                                         rule->lsm[i].type,
 229                                                         Audit_equal,
 230                                                         rule->lsm[i].rule,
 231                                                         NULL);
 232                         break;
 233                 case LSM_SUBJ_USER:
 234                 case LSM_SUBJ_ROLE:
 235                 case LSM_SUBJ_TYPE:
 236                         security_task_getsecid(tsk, &sid);
 237                         rc = security_filter_rule_match(sid,
 238                                                         rule->lsm[i].type,
 239                                                         Audit_equal,
 240                                                         rule->lsm[i].rule,
 241                                                         NULL);
 242                 default:
 243                         break;
 244                 }
 245                 if ((rc < 0) && (!retried)) {
 246                         retried = 1;
 247                         ima_lsm_update_rules();
 248                         goto retry;
 249                 }
 250                 if (!rc)
 251                         return false;
 252         }
 253         return true;
 254 }
 255
 256 /*
 257  * In addition to knowing that we need to appraise the file in general,
 258  * we need to differentiate between calling hooks, for hook specific rules.
 259  */
 260 static int get_subaction(struct ima_rule_entry *rule, int func)
 261 {
 262         if (!(rule->flags & IMA_FUNC))
 263                 return IMA_FILE_APPRAISE;
 264
 265         switch (func) {
 266         case MMAP_CHECK:
 267                 return IMA_MMAP_APPRAISE;
 268         case BPRM_CHECK:
 269                 return IMA_BPRM_APPRAISE;
 270         case MODULE_CHECK:
 271                 return IMA_MODULE_APPRAISE;
 272         case FIRMWARE_CHECK:
 273                 return IMA_FIRMWARE_APPRAISE;
 274         case FILE_CHECK:
 275         default:
 276                 return IMA_FILE_APPRAISE;
 277         }
 278 }
 279
 280 /**
 281  * ima_match_policy - decision based on LSM and other conditions
 282  * @inode: pointer to an inode for which the policy decision is being made
 283  * @func: IMA hook identifier
 284  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 285  *
 286  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 287  * conditions.
 288  *
 289  * (There is no need for locking when walking the policy list,
 290  * as elements in the list are never deleted, nor does the list
 291  * change.)
 292  */
 293 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 294                      int flags)
 295 {
 296         struct ima_rule_entry *entry;
 297         int action = 0, actmask = flags | (flags << 1);
 298
 299         list_for_each_entry(entry, ima_rules, list) {
 300
 301                 if (!(entry->action & actmask))
 302                         continue;
 303
 304                 if (!ima_match_rules(entry, inode, func, mask))
 305                         continue;
 306
 307                 action |= entry->flags & IMA_ACTION_FLAGS;
 308
 309                 action |= entry->action & IMA_DO_MASK;
 310                 if (entry->action & IMA_APPRAISE)
 311                         action |= get_subaction(entry, func);
 312
 313                 if (entry->action & IMA_DO_MASK)
 314                         actmask &= ~(entry->action | entry->action << 1);
 315                 else
 316                         actmask &= ~(entry->action | entry->action >> 1);
 317
 318                 if (!actmask)
 319                         break;
 320         }
 321
 322         return action;
 323 }
 324
 325 /*
 326  * Initialize the ima_policy_flag variable based on the currently
 327  * loaded policy.  Based on this flag, the decision to short circuit
 328  * out of a function or not call the function in the first place
 329  * can be made earlier.
 330  */
 331 void ima_update_policy_flag(void)
 332 {
 333         struct ima_rule_entry *entry;
 334
 335         ima_policy_flag = 0;
 336         list_for_each_entry(entry, ima_rules, list) {
 337                 if (entry->action & IMA_DO_MASK)
 338                         ima_policy_flag |= entry->action;
 339         }
 340
 341         if (!ima_appraise)
 342                 ima_policy_flag &= ~IMA_APPRAISE;
 343 }
 344
 345 /**
 346  * ima_init_policy - initialize the default measure rules.
 347  *
 348  * ima_rules points to either the ima_default_rules or the
 349  * the new ima_policy_rules.
 350  */
 351 void __init ima_init_policy(void)
 352 {
 353         int i, measure_entries, appraise_entries;
 354
 355         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
 356         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
 357         appraise_entries = ima_use_appraise_tcb ?
 358                          ARRAY_SIZE(default_appraise_rules) : 0;
 359
 360         for (i = 0; i < measure_entries; i++)
 361                 list_add_tail(&default_rules[i].list, &ima_default_rules);
 362
 363         for (i = 0; i < appraise_entries; i++) {
 364                 list_add_tail(&default_appraise_rules[i].list,
 365                               &ima_default_rules);
 366         }
 367
 368         ima_rules = &ima_default_rules;
 369 }
 370
 371 /**
 372  * ima_update_policy - update default_rules with new measure rules
 373  *
 374  * Called on file .release to update the default rules with a complete new
 375  * policy.  Once updated, the policy is locked, no additional rules can be
 376  * added to the policy.
 377  */
 378 void ima_update_policy(void)
 379 {
 380         ima_rules = &ima_policy_rules;
 381         ima_update_policy_flag();
 382 }
 383
 384 enum {
 385         Opt_err = -1,
 386         Opt_measure = 1, Opt_dont_measure,
 387         Opt_appraise, Opt_dont_appraise,
 388         Opt_audit,
 389         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 390         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 391         Opt_func, Opt_mask, Opt_fsmagic,
 392         Opt_uid, Opt_euid, Opt_fowner,
 393         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 394 };
 395
 396 static match_table_t policy_tokens = {
 397         {Opt_measure, "measure"},
 398         {Opt_dont_measure, "dont_measure"},
 399         {Opt_appraise, "appraise"},
 400         {Opt_dont_appraise, "dont_appraise"},
 401         {Opt_audit, "audit"},
 402         {Opt_obj_user, "obj_user=%s"},
 403         {Opt_obj_role, "obj_role=%s"},
 404         {Opt_obj_type, "obj_type=%s"},
 405         {Opt_subj_user, "subj_user=%s"},
 406         {Opt_subj_role, "subj_role=%s"},
 407         {Opt_subj_type, "subj_type=%s"},
 408         {Opt_func, "func=%s"},
 409         {Opt_mask, "mask=%s"},
 410         {Opt_fsmagic, "fsmagic=%s"},
 411         {Opt_fsuuid, "fsuuid=%s"},
 412         {Opt_uid, "uid=%s"},
 413         {Opt_euid, "euid=%s"},
 414         {Opt_fowner, "fowner=%s"},
 415         {Opt_appraise_type, "appraise_type=%s"},
 416         {Opt_permit_directio, "permit_directio"},
 417         {Opt_err, NULL}
 418 };
 419
 420 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 421                              substring_t *args, int lsm_rule, int audit_type)
 422 {
 423         int result;
 424
 425         if (entry->lsm[lsm_rule].rule)
 426                 return -EINVAL;
 427
 428         entry->lsm[lsm_rule].args_p = match_strdup(args);
 429         if (!entry->lsm[lsm_rule].args_p)
 430                 return -ENOMEM;
 431
 432         entry->lsm[lsm_rule].type = audit_type;
 433         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 434                                            Audit_equal,
 435                                            entry->lsm[lsm_rule].args_p,
 436                                            &entry->lsm[lsm_rule].rule);
 437         if (!entry->lsm[lsm_rule].rule) {
 438                 kfree(entry->lsm[lsm_rule].args_p);
 439                 return -EINVAL;
 440         }
 441
 442         return result;
 443 }
 444
 445 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 446 {
 447         audit_log_format(ab, "%s=", key);
 448         audit_log_untrustedstring(ab, value);
 449         audit_log_format(ab, " ");
 450 }
 451
 452 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 453 {
 454         struct audit_buffer *ab;
 455         char *from;
 456         char *p;
 457         int result = 0;
 458
 459         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 460
 461         entry->uid = INVALID_UID;
 462         entry->fowner = INVALID_UID;
 463         entry->action = UNKNOWN;
 464         while ((p = strsep(&rule, " \t")) != NULL) {
 465                 substring_t args[MAX_OPT_ARGS];
 466                 int token;
 467                 unsigned long lnum;
 468
 469                 if (result < 0)
 470                         break;
 471                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 472                         continue;
 473                 token = match_token(p, policy_tokens, args);
 474                 switch (token) {
 475                 case Opt_measure:
 476                         ima_log_string(ab, "action", "measure");
 477
 478                         if (entry->action != UNKNOWN)
 479                                 result = -EINVAL;
 480
 481                         entry->action = MEASURE;
 482                         break;
 483                 case Opt_dont_measure:
 484                         ima_log_string(ab, "action", "dont_measure");
 485
 486                         if (entry->action != UNKNOWN)
 487                                 result = -EINVAL;
 488
 489                         entry->action = DONT_MEASURE;
 490                         break;
 491                 case Opt_appraise:
 492                         ima_log_string(ab, "action", "appraise");
 493
 494                         if (entry->action != UNKNOWN)
 495                                 result = -EINVAL;
 496
 497                         entry->action = APPRAISE;
 498                         break;
 499                 case Opt_dont_appraise:
 500                         ima_log_string(ab, "action", "dont_appraise");
 501
 502                         if (entry->action != UNKNOWN)
 503                                 result = -EINVAL;
 504
 505                         entry->action = DONT_APPRAISE;
 506                         break;
 507                 case Opt_audit:
 508                         ima_log_string(ab, "action", "audit");
 509
 510                         if (entry->action != UNKNOWN)
 511                                 result = -EINVAL;
 512
 513                         entry->action = AUDIT;
 514                         break;
 515                 case Opt_func:
 516                         ima_log_string(ab, "func", args[0].from);
 517
 518                         if (entry->func)
 519                                 result = -EINVAL;
 520
 521                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 522                                 entry->func = FILE_CHECK;
 523                         /* PATH_CHECK is for backwards compat */
 524                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 525                                 entry->func = FILE_CHECK;
 526                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 527                                 entry->func = MODULE_CHECK;
 528                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
 529                                 entry->func = FIRMWARE_CHECK;
 530                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 531                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 532                                 entry->func = MMAP_CHECK;
 533                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 534                                 entry->func = BPRM_CHECK;
 535                         else
 536                                 result = -EINVAL;
 537                         if (!result)
 538                                 entry->flags |= IMA_FUNC;
 539                         break;
 540                 case Opt_mask:
 541                         ima_log_string(ab, "mask", args[0].from);
 542
 543                         if (entry->mask)
 544                                 result = -EINVAL;
 545
 546                         from = args[0].from;
 547                         if (*from == '^')
 548                                 from++;
 549
 550                         if ((strcmp(from, "MAY_EXEC")) == 0)
 551                                 entry->mask = MAY_EXEC;
 552                         else if (strcmp(from, "MAY_WRITE") == 0)
 553                                 entry->mask = MAY_WRITE;
 554                         else if (strcmp(from, "MAY_READ") == 0)
 555                                 entry->mask = MAY_READ;
 556                         else if (strcmp(from, "MAY_APPEND") == 0)
 557                                 entry->mask = MAY_APPEND;
 558                         else
 559                                 result = -EINVAL;
 560                         if (!result)
 561                                 entry->flags |= (*args[0].from == '^')
 562                                      ? IMA_INMASK : IMA_MASK;
 563                         break;
 564                 case Opt_fsmagic:
 565                         ima_log_string(ab, "fsmagic", args[0].from);
 566
 567                         if (entry->fsmagic) {
 568                                 result = -EINVAL;
 569                                 break;
 570                         }
 571
 572                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
 573                         if (!result)
 574                                 entry->flags |= IMA_FSMAGIC;
 575                         break;
 576                 case Opt_fsuuid:
 577                         ima_log_string(ab, "fsuuid", args[0].from);
 578
 579                         if (memchr_inv(entry->fsuuid, 0x00,
 580                                        sizeof(entry->fsuuid))) {
 581                                 result = -EINVAL;
 582                                 break;
 583                         }
 584
 585                         result = blk_part_pack_uuid(args[0].from,
 586                                                     entry->fsuuid);
 587                         if (!result)
 588                                 entry->flags |= IMA_FSUUID;
 589                         break;
 590                 case Opt_uid:
 591                         ima_log_string(ab, "uid", args[0].from);
 592                 case Opt_euid:
 593                         if (token == Opt_euid)
 594                                 ima_log_string(ab, "euid", args[0].from);
 595
 596                         if (uid_valid(entry->uid)) {
 597                                 result = -EINVAL;
 598                                 break;
 599                         }
 600
 601                         result = kstrtoul(args[0].from, 10, &lnum);
 602                         if (!result) {
 603                                 entry->uid = make_kuid(current_user_ns(),
 604                                                        (uid_t) lnum);
 605                                 if (!uid_valid(entry->uid) ||
 606                                     (uid_t)lnum != lnum)
 607                                         result = -EINVAL;
 608                                 else
 609                                         entry->flags |= (token == Opt_uid)
 610                                             ? IMA_UID : IMA_EUID;
 611                         }
 612                         break;
 613                 case Opt_fowner:
 614                         ima_log_string(ab, "fowner", args[0].from);
 615
 616                         if (uid_valid(entry->fowner)) {
 617                                 result = -EINVAL;
 618                                 break;
 619                         }
 620
 621                         result = kstrtoul(args[0].from, 10, &lnum);
 622                         if (!result) {
 623                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
 624                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
 625                                         result = -EINVAL;
 626                                 else
 627                                         entry->flags |= IMA_FOWNER;
 628                         }
 629                         break;
 630                 case Opt_obj_user:
 631                         ima_log_string(ab, "obj_user", args[0].from);
 632                         result = ima_lsm_rule_init(entry, args,
 633                                                    LSM_OBJ_USER,
 634                                                    AUDIT_OBJ_USER);
 635                         break;
 636                 case Opt_obj_role:
 637                         ima_log_string(ab, "obj_role", args[0].from);
 638                         result = ima_lsm_rule_init(entry, args,
 639                                                    LSM_OBJ_ROLE,
 640                                                    AUDIT_OBJ_ROLE);
 641                         break;
 642                 case Opt_obj_type:
 643                         ima_log_string(ab, "obj_type", args[0].from);
 644                         result = ima_lsm_rule_init(entry, args,
 645                                                    LSM_OBJ_TYPE,
 646                                                    AUDIT_OBJ_TYPE);
 647                         break;
 648                 case Opt_subj_user:
 649                         ima_log_string(ab, "subj_user", args[0].from);
 650                         result = ima_lsm_rule_init(entry, args,
 651                                                    LSM_SUBJ_USER,
 652                                                    AUDIT_SUBJ_USER);
 653                         break;
 654                 case Opt_subj_role:
 655                         ima_log_string(ab, "subj_role", args[0].from);
 656                         result = ima_lsm_rule_init(entry, args,
 657                                                    LSM_SUBJ_ROLE,
 658                                                    AUDIT_SUBJ_ROLE);
 659                         break;
 660                 case Opt_subj_type:
 661                         ima_log_string(ab, "subj_type", args[0].from);
 662                         result = ima_lsm_rule_init(entry, args,
 663                                                    LSM_SUBJ_TYPE,
 664                                                    AUDIT_SUBJ_TYPE);
 665                         break;
 666                 case Opt_appraise_type:
 667                         if (entry->action != APPRAISE) {
 668                                 result = -EINVAL;
 669                                 break;
 670                         }
 671
 672                         ima_log_string(ab, "appraise_type", args[0].from);
 673                         if ((strcmp(args[0].from, "imasig")) == 0)
 674                                 entry->flags |= IMA_DIGSIG_REQUIRED;
 675                         else
 676                                 result = -EINVAL;
 677                         break;
 678                 case Opt_permit_directio:
 679                         entry->flags |= IMA_PERMIT_DIRECTIO;
 680                         break;
 681                 case Opt_err:
 682                         ima_log_string(ab, "UNKNOWN", p);
 683                         result = -EINVAL;
 684                         break;
 685                 }
 686         }
 687         if (!result && (entry->action == UNKNOWN))
 688                 result = -EINVAL;
 689         else if (entry->func == MODULE_CHECK)
 690                 ima_appraise |= IMA_APPRAISE_MODULES;
 691         else if (entry->func == FIRMWARE_CHECK)
 692                 ima_appraise |= IMA_APPRAISE_FIRMWARE;
 693         audit_log_format(ab, "res=%d", !result);
 694         audit_log_end(ab);
 695         return result;
 696 }
 697
 698 /**
 699  * ima_parse_add_rule - add a rule to ima_policy_rules
 700  * @rule - ima measurement policy rule
 701  *
 702  * Uses a mutex to protect the policy list from multiple concurrent writers.
 703  * Returns the length of the rule parsed, an error code on failure
 704  */
 705 ssize_t ima_parse_add_rule(char *rule)
 706 {
 707         static const char op[] = "update_policy";
 708         char *p;
 709         struct ima_rule_entry *entry;
 710         ssize_t result, len;
 711         int audit_info = 0;
 712
 713         p = strsep(&rule, "\n");
 714         len = strlen(p) + 1;
 715         p += strspn(p, " \t");
 716
 717         if (*p == '#' || *p == '\0')
 718                 return len;
 719
 720         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 721         if (!entry) {
 722                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 723                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 724                 return -ENOMEM;
 725         }
 726
 727         INIT_LIST_HEAD(&entry->list);
 728
 729         result = ima_parse_rule(p, entry);
 730         if (result) {
 731                 kfree(entry);
 732                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 733                                     NULL, op, "invalid-policy", result,
 734                                     audit_info);
 735                 return result;
 736         }
 737
 738         mutex_lock(&ima_rules_mutex);
 739         list_add_tail(&entry->list, &ima_policy_rules);
 740         mutex_unlock(&ima_rules_mutex);
 741
 742         return len;
 743 }
 744
 745 /* ima_delete_rules called to cleanup invalid policy */
 746 void ima_delete_rules(void)
 747 {
 748         struct ima_rule_entry *entry, *tmp;
 749         int i;
 750
 751         mutex_lock(&ima_rules_mutex);
 752         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 753                 for (i = 0; i < MAX_LSM_RULES; i++)
 754                         kfree(entry->lsm[i].args_p);
 755
 756                 list_del(&entry->list);
 757                 kfree(entry);
 758         }
 759         mutex_unlock(&ima_rules_mutex);
 760 }