security/integrity/ima/ima_policy.c

   1 /*
   2  * Copyright (C) 2008 IBM Corporation
   3  * Author: Mimi Zohar <zohar@us.ibm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, version 2 of the License.
   8  *
   9  * ima_policy.c
  10  *      - initialize default measure policy rules
  11  *
  12  */
  13 #include <linux/module.h>
  14 #include <linux/list.h>
  15 #include <linux/security.h>
  16 #include <linux/magic.h>
  17 #include <linux/parser.h>
  18 #include <linux/slab.h>
  19 #include <linux/genhd.h>
  20
  21 #include "ima.h"
  22
  23 /* flags definitions */
  24 #define IMA_FUNC        0x0001
  25 #define IMA_MASK        0x0002
  26 #define IMA_FSMAGIC     0x0004
  27 #define IMA_UID         0x0008
  28 #define IMA_FOWNER      0x0010
  29 #define IMA_FSUUID      0x0020
  30
  31 #define UNKNOWN         0
  32 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  33 #define DONT_MEASURE    0x0002
  34 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  35 #define DONT_APPRAISE   0x0008
  36 #define AUDIT           0x0040
  37
  38 int ima_policy_flag;
  39
  40 #define MAX_LSM_RULES 6
  41 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  42         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  43 };
  44
  45 struct ima_rule_entry {
  46         struct list_head list;
  47         int action;
  48         unsigned int flags;
  49         enum ima_hooks func;
  50         int mask;
  51         unsigned long fsmagic;
  52         u8 fsuuid[16];
  53         kuid_t uid;
  54         kuid_t fowner;
  55         struct {
  56                 void *rule;     /* LSM file metadata specific */
  57                 void *args_p;   /* audit value */
  58                 int type;       /* audit type */
  59         } lsm[MAX_LSM_RULES];
  60 };
  61
  62 /*
  63  * Without LSM specific knowledge, the default policy can only be
  64  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  65  */
  66
  67 /*
  68  * The minimum rule set to allow for full TCB coverage.  Measures all files
  69  * opened or mmap for exec and everything read by root.  Dangerous because
  70  * normal users can easily run the machine out of memory simply building
  71  * and running executables.
  72  */
  73 static struct ima_rule_entry default_rules[] = {
  74         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  75         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  76         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  77         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  78         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  79         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  80         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  81         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  82         {.action = 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         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
  90 };
  91
  92 static struct ima_rule_entry default_appraise_rules[] = {
  93         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  94         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  95         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  96         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  97         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
  98         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  99         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 100         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 101         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 102         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 103         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 104 };
 105
 106 static LIST_HEAD(ima_default_rules);
 107 static LIST_HEAD(ima_policy_rules);
 108 static struct list_head *ima_rules;
 109
 110 static DEFINE_MUTEX(ima_rules_mutex);
 111
 112 static bool ima_use_tcb __initdata;
 113 static int __init default_measure_policy_setup(char *str)
 114 {
 115         ima_use_tcb = 1;
 116         return 1;
 117 }
 118 __setup("ima_tcb", default_measure_policy_setup);
 119
 120 static bool ima_use_appraise_tcb __initdata;
 121 static int __init default_appraise_policy_setup(char *str)
 122 {
 123         ima_use_appraise_tcb = 1;
 124         return 1;
 125 }
 126 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 127
 128 /*
 129  * Although the IMA policy does not change, the LSM policy can be
 130  * reloaded, leaving the IMA LSM based rules referring to the old,
 131  * stale LSM policy.
 132  *
 133  * Update the IMA LSM based rules to reflect the reloaded LSM policy.
 134  * We assume the rules still exist; and BUG_ON() if they don't.
 135  */
 136 static void ima_lsm_update_rules(void)
 137 {
 138         struct ima_rule_entry *entry, *tmp;
 139         int result;
 140         int i;
 141
 142         mutex_lock(&ima_rules_mutex);
 143         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 144                 for (i = 0; i < MAX_LSM_RULES; i++) {
 145                         if (!entry->lsm[i].rule)
 146                                 continue;
 147                         result = security_filter_rule_init(entry->lsm[i].type,
 148                                                            Audit_equal,
 149                                                            entry->lsm[i].args_p,
 150                                                            &entry->lsm[i].rule);
 151                         BUG_ON(!entry->lsm[i].rule);
 152                 }
 153         }
 154         mutex_unlock(&ima_rules_mutex);
 155 }
 156
 157 /**
 158  * ima_match_rules - determine whether an inode matches the measure rule.
 159  * @rule: a pointer to a rule
 160  * @inode: a pointer to an inode
 161  * @func: LIM hook identifier
 162  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 163  *
 164  * Returns true on rule match, false on failure.
 165  */
 166 static bool ima_match_rules(struct ima_rule_entry *rule,
 167                             struct inode *inode, enum ima_hooks func, int mask)
 168 {
 169         struct task_struct *tsk = current;
 170         const struct cred *cred = current_cred();
 171         int i;
 172
 173         if ((rule->flags & IMA_FUNC) &&
 174             (rule->func != func && func != POST_SETATTR))
 175                 return false;
 176         if ((rule->flags & IMA_MASK) &&
 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_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
 188                 return false;
 189         for (i = 0; i < MAX_LSM_RULES; i++) {
 190                 int rc = 0;
 191                 u32 osid, sid;
 192                 int retried = 0;
 193
 194                 if (!rule->lsm[i].rule)
 195                         continue;
 196 retry:
 197                 switch (i) {
 198                 case LSM_OBJ_USER:
 199                 case LSM_OBJ_ROLE:
 200                 case LSM_OBJ_TYPE:
 201                         security_inode_getsecid(inode, &osid);
 202                         rc = security_filter_rule_match(osid,
 203                                                         rule->lsm[i].type,
 204                                                         Audit_equal,
 205                                                         rule->lsm[i].rule,
 206                                                         NULL);
 207                         break;
 208                 case LSM_SUBJ_USER:
 209                 case LSM_SUBJ_ROLE:
 210                 case LSM_SUBJ_TYPE:
 211                         security_task_getsecid(tsk, &sid);
 212                         rc = security_filter_rule_match(sid,
 213                                                         rule->lsm[i].type,
 214                                                         Audit_equal,
 215                                                         rule->lsm[i].rule,
 216                                                         NULL);
 217                 default:
 218                         break;
 219                 }
 220                 if ((rc < 0) && (!retried)) {
 221                         retried = 1;
 222                         ima_lsm_update_rules();
 223                         goto retry;
 224                 }
 225                 if (!rc)
 226                         return false;
 227         }
 228         return true;
 229 }
 230
 231 /*
 232  * In addition to knowing that we need to appraise the file in general,
 233  * we need to differentiate between calling hooks, for hook specific rules.
 234  */
 235 static int get_subaction(struct ima_rule_entry *rule, int func)
 236 {
 237         if (!(rule->flags & IMA_FUNC))
 238                 return IMA_FILE_APPRAISE;
 239
 240         switch (func) {
 241         case MMAP_CHECK:
 242                 return IMA_MMAP_APPRAISE;
 243         case BPRM_CHECK:
 244                 return IMA_BPRM_APPRAISE;
 245         case MODULE_CHECK:
 246                 return IMA_MODULE_APPRAISE;
 247         case FIRMWARE_CHECK:
 248                 return IMA_FIRMWARE_APPRAISE;
 249         case FILE_CHECK:
 250         default:
 251                 return IMA_FILE_APPRAISE;
 252         }
 253 }
 254
 255 /**
 256  * ima_match_policy - decision based on LSM and other conditions
 257  * @inode: pointer to an inode for which the policy decision is being made
 258  * @func: IMA hook identifier
 259  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 260  *
 261  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 262  * conditions.
 263  *
 264  * (There is no need for locking when walking the policy list,
 265  * as elements in the list are never deleted, nor does the list
 266  * change.)
 267  */
 268 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 269                      int flags)
 270 {
 271         struct ima_rule_entry *entry;
 272         int action = 0, actmask = flags | (flags << 1);
 273
 274         list_for_each_entry(entry, ima_rules, list) {
 275
 276                 if (!(entry->action & actmask))
 277                         continue;
 278
 279                 if (!ima_match_rules(entry, inode, func, mask))
 280                         continue;
 281
 282                 action |= entry->flags & IMA_ACTION_FLAGS;
 283
 284                 action |= entry->action & IMA_DO_MASK;
 285                 if (entry->action & IMA_APPRAISE)
 286                         action |= get_subaction(entry, func);
 287
 288                 if (entry->action & IMA_DO_MASK)
 289                         actmask &= ~(entry->action | entry->action << 1);
 290                 else
 291                         actmask &= ~(entry->action | entry->action >> 1);
 292
 293                 if (!actmask)
 294                         break;
 295         }
 296
 297         return action;
 298 }
 299
 300 /*
 301  * Initialize the ima_policy_flag variable based on the currently
 302  * loaded policy.  Based on this flag, the decision to short circuit
 303  * out of a function or not call the function in the first place
 304  * can be made earlier.
 305  */
 306 void ima_update_policy_flag(void)
 307 {
 308         struct ima_rule_entry *entry;
 309
 310         ima_policy_flag = 0;
 311         list_for_each_entry(entry, ima_rules, list) {
 312                 if (entry->action & IMA_DO_MASK)
 313                         ima_policy_flag |= entry->action;
 314         }
 315
 316         if (!ima_appraise)
 317                 ima_policy_flag &= ~IMA_APPRAISE;
 318 }
 319
 320 /**
 321  * ima_init_policy - initialize the default measure rules.
 322  *
 323  * ima_rules points to either the ima_default_rules or the
 324  * the new ima_policy_rules.
 325  */
 326 void __init ima_init_policy(void)
 327 {
 328         int i, measure_entries, appraise_entries;
 329
 330         /* if !ima_use_tcb set entries = 0 so we load NO default rules */
 331         measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0;
 332         appraise_entries = ima_use_appraise_tcb ?
 333                          ARRAY_SIZE(default_appraise_rules) : 0;
 334
 335         for (i = 0; i < measure_entries + appraise_entries; i++) {
 336                 if (i < measure_entries)
 337                         list_add_tail(&default_rules[i].list,
 338                                       &ima_default_rules);
 339                 else {
 340                         int j = i - measure_entries;
 341
 342                         list_add_tail(&default_appraise_rules[j].list,
 343                                       &ima_default_rules);
 344                 }
 345         }
 346
 347         ima_rules = &ima_default_rules;
 348 }
 349
 350 /**
 351  * ima_update_policy - update default_rules with new measure rules
 352  *
 353  * Called on file .release to update the default rules with a complete new
 354  * policy.  Once updated, the policy is locked, no additional rules can be
 355  * added to the policy.
 356  */
 357 void ima_update_policy(void)
 358 {
 359         static const char op[] = "policy_update";
 360         const char *cause = "already-exists";
 361         int result = 1;
 362         int audit_info = 0;
 363
 364         if (ima_rules == &ima_default_rules) {
 365                 ima_rules = &ima_policy_rules;
 366                 ima_update_policy_flag();
 367                 cause = "complete";
 368                 result = 0;
 369         }
 370         integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 371                             NULL, op, cause, result, audit_info);
 372 }
 373
 374 enum {
 375         Opt_err = -1,
 376         Opt_measure = 1, Opt_dont_measure,
 377         Opt_appraise, Opt_dont_appraise,
 378         Opt_audit,
 379         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 380         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 381         Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
 382         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 383 };
 384
 385 static match_table_t policy_tokens = {
 386         {Opt_measure, "measure"},
 387         {Opt_dont_measure, "dont_measure"},
 388         {Opt_appraise, "appraise"},
 389         {Opt_dont_appraise, "dont_appraise"},
 390         {Opt_audit, "audit"},
 391         {Opt_obj_user, "obj_user=%s"},
 392         {Opt_obj_role, "obj_role=%s"},
 393         {Opt_obj_type, "obj_type=%s"},
 394         {Opt_subj_user, "subj_user=%s"},
 395         {Opt_subj_role, "subj_role=%s"},
 396         {Opt_subj_type, "subj_type=%s"},
 397         {Opt_func, "func=%s"},
 398         {Opt_mask, "mask=%s"},
 399         {Opt_fsmagic, "fsmagic=%s"},
 400         {Opt_fsuuid, "fsuuid=%s"},
 401         {Opt_uid, "uid=%s"},
 402         {Opt_fowner, "fowner=%s"},
 403         {Opt_appraise_type, "appraise_type=%s"},
 404         {Opt_permit_directio, "permit_directio"},
 405         {Opt_err, NULL}
 406 };
 407
 408 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 409                              substring_t *args, int lsm_rule, int audit_type)
 410 {
 411         int result;
 412
 413         if (entry->lsm[lsm_rule].rule)
 414                 return -EINVAL;
 415
 416         entry->lsm[lsm_rule].args_p = match_strdup(args);
 417         if (!entry->lsm[lsm_rule].args_p)
 418                 return -ENOMEM;
 419
 420         entry->lsm[lsm_rule].type = audit_type;
 421         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 422                                            Audit_equal,
 423                                            entry->lsm[lsm_rule].args_p,
 424                                            &entry->lsm[lsm_rule].rule);
 425         if (!entry->lsm[lsm_rule].rule) {
 426                 kfree(entry->lsm[lsm_rule].args_p);
 427                 return -EINVAL;
 428         }
 429
 430         return result;
 431 }
 432
 433 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 434 {
 435         audit_log_format(ab, "%s=", key);
 436         audit_log_untrustedstring(ab, value);
 437         audit_log_format(ab, " ");
 438 }
 439
 440 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 441 {
 442         struct audit_buffer *ab;
 443         char *p;
 444         int result = 0;
 445
 446         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 447
 448         entry->uid = INVALID_UID;
 449         entry->fowner = INVALID_UID;
 450         entry->action = UNKNOWN;
 451         while ((p = strsep(&rule, " \t")) != NULL) {
 452                 substring_t args[MAX_OPT_ARGS];
 453                 int token;
 454                 unsigned long lnum;
 455
 456                 if (result < 0)
 457                         break;
 458                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 459                         continue;
 460                 token = match_token(p, policy_tokens, args);
 461                 switch (token) {
 462                 case Opt_measure:
 463                         ima_log_string(ab, "action", "measure");
 464
 465                         if (entry->action != UNKNOWN)
 466                                 result = -EINVAL;
 467
 468                         entry->action = MEASURE;
 469                         break;
 470                 case Opt_dont_measure:
 471                         ima_log_string(ab, "action", "dont_measure");
 472
 473                         if (entry->action != UNKNOWN)
 474                                 result = -EINVAL;
 475
 476                         entry->action = DONT_MEASURE;
 477                         break;
 478                 case Opt_appraise:
 479                         ima_log_string(ab, "action", "appraise");
 480
 481                         if (entry->action != UNKNOWN)
 482                                 result = -EINVAL;
 483
 484                         entry->action = APPRAISE;
 485                         break;
 486                 case Opt_dont_appraise:
 487                         ima_log_string(ab, "action", "dont_appraise");
 488
 489                         if (entry->action != UNKNOWN)
 490                                 result = -EINVAL;
 491
 492                         entry->action = DONT_APPRAISE;
 493                         break;
 494                 case Opt_audit:
 495                         ima_log_string(ab, "action", "audit");
 496
 497                         if (entry->action != UNKNOWN)
 498                                 result = -EINVAL;
 499
 500                         entry->action = AUDIT;
 501                         break;
 502                 case Opt_func:
 503                         ima_log_string(ab, "func", args[0].from);
 504
 505                         if (entry->func)
 506                                 result = -EINVAL;
 507
 508                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 509                                 entry->func = FILE_CHECK;
 510                         /* PATH_CHECK is for backwards compat */
 511                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 512                                 entry->func = FILE_CHECK;
 513                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 514                                 entry->func = MODULE_CHECK;
 515                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
 516                                 entry->func = FIRMWARE_CHECK;
 517                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 518                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 519                                 entry->func = MMAP_CHECK;
 520                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 521                                 entry->func = BPRM_CHECK;
 522                         else
 523                                 result = -EINVAL;
 524                         if (!result)
 525                                 entry->flags |= IMA_FUNC;
 526                         break;
 527                 case Opt_mask:
 528                         ima_log_string(ab, "mask", args[0].from);
 529
 530                         if (entry->mask)
 531                                 result = -EINVAL;
 532
 533                         if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
 534                                 entry->mask = MAY_EXEC;
 535                         else if (strcmp(args[0].from, "MAY_WRITE") == 0)
 536                                 entry->mask = MAY_WRITE;
 537                         else if (strcmp(args[0].from, "MAY_READ") == 0)
 538                                 entry->mask = MAY_READ;
 539                         else if (strcmp(args[0].from, "MAY_APPEND") == 0)
 540                                 entry->mask = MAY_APPEND;
 541                         else
 542                                 result = -EINVAL;
 543                         if (!result)
 544                                 entry->flags |= IMA_MASK;
 545                         break;
 546                 case Opt_fsmagic:
 547                         ima_log_string(ab, "fsmagic", args[0].from);
 548
 549                         if (entry->fsmagic) {
 550                                 result = -EINVAL;
 551                                 break;
 552                         }
 553
 554                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
 555                         if (!result)
 556                                 entry->flags |= IMA_FSMAGIC;
 557                         break;
 558                 case Opt_fsuuid:
 559                         ima_log_string(ab, "fsuuid", args[0].from);
 560
 561                         if (memchr_inv(entry->fsuuid, 0x00,
 562                                        sizeof(entry->fsuuid))) {
 563                                 result = -EINVAL;
 564                                 break;
 565                         }
 566
 567                         result = blk_part_pack_uuid(args[0].from,
 568                                                     entry->fsuuid);
 569                         if (!result)
 570                                 entry->flags |= IMA_FSUUID;
 571                         break;
 572                 case Opt_uid:
 573                         ima_log_string(ab, "uid", args[0].from);
 574
 575                         if (uid_valid(entry->uid)) {
 576                                 result = -EINVAL;
 577                                 break;
 578                         }
 579
 580                         result = kstrtoul(args[0].from, 10, &lnum);
 581                         if (!result) {
 582                                 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
 583                                 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
 584                                         result = -EINVAL;
 585                                 else
 586                                         entry->flags |= IMA_UID;
 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 = kstrtoul(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         else if (entry->func == FIRMWARE_CHECK)
 668                 ima_appraise |= IMA_APPRAISE_FIRMWARE;
 669         audit_log_format(ab, "res=%d", !result);
 670         audit_log_end(ab);
 671         return result;
 672 }
 673
 674 /**
 675  * ima_parse_add_rule - add a rule to ima_policy_rules
 676  * @rule - ima measurement policy rule
 677  *
 678  * Uses a mutex to protect the policy list from multiple concurrent writers.
 679  * Returns the length of the rule parsed, an error code on failure
 680  */
 681 ssize_t ima_parse_add_rule(char *rule)
 682 {
 683         static const char op[] = "update_policy";
 684         char *p;
 685         struct ima_rule_entry *entry;
 686         ssize_t result, len;
 687         int audit_info = 0;
 688
 689         /* Prevent installed policy from changing */
 690         if (ima_rules != &ima_default_rules) {
 691                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 692                                     NULL, op, "already-exists",
 693                                     -EACCES, audit_info);
 694                 return -EACCES;
 695         }
 696
 697         p = strsep(&rule, "\n");
 698         len = strlen(p) + 1;
 699         p += strspn(p, " \t");
 700
 701         if (*p == '#' || *p == '\0')
 702                 return len;
 703
 704         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 705         if (!entry) {
 706                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 707                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 708                 return -ENOMEM;
 709         }
 710
 711         INIT_LIST_HEAD(&entry->list);
 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 }