security/integrity/ima/ima_policy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 IBM Corporation
   4  * Author: Mimi Zohar <zohar@us.ibm.com>
   5  *
   6  * ima_policy.c
   7  *      - initialize default measure policy rules
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/kernel_read_file.h>
  13 #include <linux/fs.h>
  14 #include <linux/security.h>
  15 #include <linux/magic.h>
  16 #include <linux/parser.h>
  17 #include <linux/slab.h>
  18 #include <linux/rculist.h>
  19 #include <linux/genhd.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/ima.h>
  22
  23 #include "ima.h"
  24
  25 /* flags definitions */
  26 #define IMA_FUNC        0x0001
  27 #define IMA_MASK        0x0002
  28 #define IMA_FSMAGIC     0x0004
  29 #define IMA_UID         0x0008
  30 #define IMA_FOWNER      0x0010
  31 #define IMA_FSUUID      0x0020
  32 #define IMA_INMASK      0x0040
  33 #define IMA_EUID        0x0080
  34 #define IMA_PCR         0x0100
  35 #define IMA_FSNAME      0x0200
  36 #define IMA_KEYRINGS    0x0400
  37
  38 #define UNKNOWN         0
  39 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  40 #define DONT_MEASURE    0x0002
  41 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  42 #define DONT_APPRAISE   0x0008
  43 #define AUDIT           0x0040
  44 #define HASH            0x0100
  45 #define DONT_HASH       0x0200
  46
  47 #define INVALID_PCR(a) (((a) < 0) || \
  48         (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
  49
  50 int ima_policy_flag;
  51 static int temp_ima_appraise;
  52 static int build_ima_appraise __ro_after_init;
  53
  54 #define MAX_LSM_RULES 6
  55 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  56         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  57 };
  58
  59 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  60
  61 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
  62
  63 struct ima_rule_opt_list {
  64         size_t count;
  65         char *items[];
  66 };
  67
  68 struct ima_rule_entry {
  69         struct list_head list;
  70         int action;
  71         unsigned int flags;
  72         enum ima_hooks func;
  73         int mask;
  74         unsigned long fsmagic;
  75         uuid_t fsuuid;
  76         kuid_t uid;
  77         kuid_t fowner;
  78         bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
  79         bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
  80         int pcr;
  81         struct {
  82                 void *rule;     /* LSM file metadata specific */
  83                 char *args_p;   /* audit value */
  84                 int type;       /* audit type */
  85         } lsm[MAX_LSM_RULES];
  86         char *fsname;
  87         struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
  88         struct ima_template_desc *template;
  89 };
  90
  91 /*
  92  * Without LSM specific knowledge, the default policy can only be
  93  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  94  */
  95
  96 /*
  97  * The minimum rule set to allow for full TCB coverage.  Measures all files
  98  * opened or mmap for exec and everything read by root.  Dangerous because
  99  * normal users can easily run the machine out of memory simply building
 100  * and running executables.
 101  */
 102 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
 103         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 104         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 105         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 106         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 107         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 108         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 109         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 110         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 111         {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 112         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
 113          .flags = IMA_FSMAGIC},
 114         {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
 115          .flags = IMA_FSMAGIC},
 116         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 117         {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
 118 };
 119
 120 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
 121         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 122          .flags = IMA_FUNC | IMA_MASK},
 123         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 124          .flags = IMA_FUNC | IMA_MASK},
 125         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 126          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 127          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 128         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 129         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 130 };
 131
 132 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
 133         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 134          .flags = IMA_FUNC | IMA_MASK},
 135         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 136          .flags = IMA_FUNC | IMA_MASK},
 137         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 138          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 139          .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 140         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 141          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 142          .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 143         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 144         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 145         {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
 146 };
 147
 148 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
 149         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 150         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 151         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 152         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 153         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 154         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 155         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 156         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 157         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 158         {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 159         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 160         {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
 161         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 162         {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 163 #ifdef CONFIG_IMA_WRITE_POLICY
 164         {.action = APPRAISE, .func = POLICY_CHECK,
 165         .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 166 #endif
 167 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 168         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 169          .flags = IMA_FOWNER},
 170 #else
 171         /* force signature */
 172         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 173          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 174 #endif
 175 };
 176
 177 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 178 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
 179         {.action = APPRAISE, .func = MODULE_CHECK,
 180          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 181 #endif
 182 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
 183         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 184          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 185 #endif
 186 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
 187         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 188          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 189 #endif
 190 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
 191         {.action = APPRAISE, .func = POLICY_CHECK,
 192          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 193 #endif
 194 };
 195
 196 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 197         {.action = APPRAISE, .func = MODULE_CHECK,
 198          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 199         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 200          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 201         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 202          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 203         {.action = APPRAISE, .func = POLICY_CHECK,
 204          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 205 };
 206
 207 /* An array of architecture specific rules */
 208 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 209
 210 static LIST_HEAD(ima_default_rules);
 211 static LIST_HEAD(ima_policy_rules);
 212 static LIST_HEAD(ima_temp_rules);
 213 static struct list_head *ima_rules = &ima_default_rules;
 214
 215 static int ima_policy __initdata;
 216
 217 static int __init default_measure_policy_setup(char *str)
 218 {
 219         if (ima_policy)
 220                 return 1;
 221
 222         ima_policy = ORIGINAL_TCB;
 223         return 1;
 224 }
 225 __setup("ima_tcb", default_measure_policy_setup);
 226
 227 static bool ima_use_appraise_tcb __initdata;
 228 static bool ima_use_secure_boot __initdata;
 229 static bool ima_fail_unverifiable_sigs __ro_after_init;
 230 static int __init policy_setup(char *str)
 231 {
 232         char *p;
 233
 234         while ((p = strsep(&str, " |\n")) != NULL) {
 235                 if (*p == ' ')
 236                         continue;
 237                 if ((strcmp(p, "tcb") == 0) && !ima_policy)
 238                         ima_policy = DEFAULT_TCB;
 239                 else if (strcmp(p, "appraise_tcb") == 0)
 240                         ima_use_appraise_tcb = true;
 241                 else if (strcmp(p, "secure_boot") == 0)
 242                         ima_use_secure_boot = true;
 243                 else if (strcmp(p, "fail_securely") == 0)
 244                         ima_fail_unverifiable_sigs = true;
 245                 else
 246                         pr_err("policy \"%s\" not found", p);
 247         }
 248
 249         return 1;
 250 }
 251 __setup("ima_policy=", policy_setup);
 252
 253 static int __init default_appraise_policy_setup(char *str)
 254 {
 255         ima_use_appraise_tcb = true;
 256         return 1;
 257 }
 258 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 259
 260 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 261 {
 262         struct ima_rule_opt_list *opt_list;
 263         size_t count = 0;
 264         char *src_copy;
 265         char *cur, *next;
 266         size_t i;
 267
 268         src_copy = match_strdup(src);
 269         if (!src_copy)
 270                 return ERR_PTR(-ENOMEM);
 271
 272         next = src_copy;
 273         while ((cur = strsep(&next, "|"))) {
 274                 /* Don't accept an empty list item */
 275                 if (!(*cur)) {
 276                         kfree(src_copy);
 277                         return ERR_PTR(-EINVAL);
 278                 }
 279                 count++;
 280         }
 281
 282         /* Don't accept an empty list */
 283         if (!count) {
 284                 kfree(src_copy);
 285                 return ERR_PTR(-EINVAL);
 286         }
 287
 288         opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
 289         if (!opt_list) {
 290                 kfree(src_copy);
 291                 return ERR_PTR(-ENOMEM);
 292         }
 293
 294         /*
 295          * strsep() has already replaced all instances of '|' with '\0',
 296          * leaving a byte sequence of NUL-terminated strings. Reference each
 297          * string with the array of items.
 298          *
 299          * IMPORTANT: Ownership of the allocated buffer is transferred from
 300          * src_copy to the first element in the items array. To free the
 301          * buffer, kfree() must only be called on the first element of the
 302          * array.
 303          */
 304         for (i = 0, cur = src_copy; i < count; i++) {
 305                 opt_list->items[i] = cur;
 306                 cur = strchr(cur, '\0') + 1;
 307         }
 308         opt_list->count = count;
 309
 310         return opt_list;
 311 }
 312
 313 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 314 {
 315         if (!opt_list)
 316                 return;
 317
 318         if (opt_list->count) {
 319                 kfree(opt_list->items[0]);
 320                 opt_list->count = 0;
 321         }
 322
 323         kfree(opt_list);
 324 }
 325
 326 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 327 {
 328         int i;
 329
 330         for (i = 0; i < MAX_LSM_RULES; i++) {
 331                 ima_filter_rule_free(entry->lsm[i].rule);
 332                 kfree(entry->lsm[i].args_p);
 333         }
 334 }
 335
 336 static void ima_free_rule(struct ima_rule_entry *entry)
 337 {
 338         if (!entry)
 339                 return;
 340
 341         /*
 342          * entry->template->fields may be allocated in ima_parse_rule() but that
 343          * reference is owned by the corresponding ima_template_desc element in
 344          * the defined_templates list and cannot be freed here
 345          */
 346         kfree(entry->fsname);
 347         ima_free_rule_opt_list(entry->keyrings);
 348         ima_lsm_free_rule(entry);
 349         kfree(entry);
 350 }
 351
 352 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 353 {
 354         struct ima_rule_entry *nentry;
 355         int i;
 356
 357         /*
 358          * Immutable elements are copied over as pointers and data; only
 359          * lsm rules can change
 360          */
 361         nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
 362         if (!nentry)
 363                 return NULL;
 364
 365         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 366
 367         for (i = 0; i < MAX_LSM_RULES; i++) {
 368                 if (!entry->lsm[i].args_p)
 369                         continue;
 370
 371                 nentry->lsm[i].type = entry->lsm[i].type;
 372                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 373                 /*
 374                  * Remove the reference from entry so that the associated
 375                  * memory will not be freed during a later call to
 376                  * ima_lsm_free_rule(entry).
 377                  */
 378                 entry->lsm[i].args_p = NULL;
 379
 380                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 381                                      nentry->lsm[i].args_p,
 382                                      &nentry->lsm[i].rule);
 383                 if (!nentry->lsm[i].rule)
 384                         pr_warn("rule for LSM \'%s\' is undefined\n",
 385                                 nentry->lsm[i].args_p);
 386         }
 387         return nentry;
 388 }
 389
 390 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 391 {
 392         struct ima_rule_entry *nentry;
 393
 394         nentry = ima_lsm_copy_rule(entry);
 395         if (!nentry)
 396                 return -ENOMEM;
 397
 398         list_replace_rcu(&entry->list, &nentry->list);
 399         synchronize_rcu();
 400         /*
 401          * ima_lsm_copy_rule() shallow copied all references, except for the
 402          * LSM references, from entry to nentry so we only want to free the LSM
 403          * references and the entry itself. All other memory refrences will now
 404          * be owned by nentry.
 405          */
 406         ima_lsm_free_rule(entry);
 407         kfree(entry);
 408
 409         return 0;
 410 }
 411
 412 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 413 {
 414         int i;
 415
 416         for (i = 0; i < MAX_LSM_RULES; i++)
 417                 if (entry->lsm[i].args_p)
 418                         return true;
 419
 420         return false;
 421 }
 422
 423 /*
 424  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 425  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 426  * the reloaded LSM policy.
 427  */
 428 static void ima_lsm_update_rules(void)
 429 {
 430         struct ima_rule_entry *entry, *e;
 431         int result;
 432
 433         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 434                 if (!ima_rule_contains_lsm_cond(entry))
 435                         continue;
 436
 437                 result = ima_lsm_update_rule(entry);
 438                 if (result) {
 439                         pr_err("lsm rule update error %d\n", result);
 440                         return;
 441                 }
 442         }
 443 }
 444
 445 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 446                           void *lsm_data)
 447 {
 448         if (event != LSM_POLICY_CHANGE)
 449                 return NOTIFY_DONE;
 450
 451         ima_lsm_update_rules();
 452         return NOTIFY_OK;
 453 }
 454
 455 /**
 456  * ima_match_keyring - determine whether the keyring matches the measure rule
 457  * @rule: a pointer to a rule
 458  * @keyring: name of the keyring to match against the measure rule
 459  * @cred: a pointer to a credentials structure for user validation
 460  *
 461  * Returns true if keyring matches one in the rule, false otherwise.
 462  */
 463 static bool ima_match_keyring(struct ima_rule_entry *rule,
 464                               const char *keyring, const struct cred *cred)
 465 {
 466         bool matched = false;
 467         size_t i;
 468
 469         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 470                 return false;
 471
 472         if (!rule->keyrings)
 473                 return true;
 474
 475         if (!keyring)
 476                 return false;
 477
 478         for (i = 0; i < rule->keyrings->count; i++) {
 479                 if (!strcmp(rule->keyrings->items[i], keyring)) {
 480                         matched = true;
 481                         break;
 482                 }
 483         }
 484
 485         return matched;
 486 }
 487
 488 /**
 489  * ima_match_rules - determine whether an inode matches the policy rule.
 490  * @rule: a pointer to a rule
 491  * @mnt_userns: user namespace of the mount the inode was found from
 492  * @inode: a pointer to an inode
 493  * @cred: a pointer to a credentials structure for user validation
 494  * @secid: the secid of the task to be validated
 495  * @func: LIM hook identifier
 496  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 497  * @keyring: keyring name to check in policy for KEY_CHECK func
 498  *
 499  * Returns true on rule match, false on failure.
 500  */
 501 static bool ima_match_rules(struct ima_rule_entry *rule,
 502                             struct user_namespace *mnt_userns,
 503                             struct inode *inode, const struct cred *cred,
 504                             u32 secid, enum ima_hooks func, int mask,
 505                             const char *keyring)
 506 {
 507         int i;
 508
 509         if (func == KEY_CHECK) {
 510                 return (rule->flags & IMA_FUNC) && (rule->func == func) &&
 511                        ima_match_keyring(rule, keyring, cred);
 512         }
 513         if ((rule->flags & IMA_FUNC) &&
 514             (rule->func != func && func != POST_SETATTR))
 515                 return false;
 516         if ((rule->flags & IMA_MASK) &&
 517             (rule->mask != mask && func != POST_SETATTR))
 518                 return false;
 519         if ((rule->flags & IMA_INMASK) &&
 520             (!(rule->mask & mask) && func != POST_SETATTR))
 521                 return false;
 522         if ((rule->flags & IMA_FSMAGIC)
 523             && rule->fsmagic != inode->i_sb->s_magic)
 524                 return false;
 525         if ((rule->flags & IMA_FSNAME)
 526             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 527                 return false;
 528         if ((rule->flags & IMA_FSUUID) &&
 529             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 530                 return false;
 531         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 532                 return false;
 533         if (rule->flags & IMA_EUID) {
 534                 if (has_capability_noaudit(current, CAP_SETUID)) {
 535                         if (!rule->uid_op(cred->euid, rule->uid)
 536                             && !rule->uid_op(cred->suid, rule->uid)
 537                             && !rule->uid_op(cred->uid, rule->uid))
 538                                 return false;
 539                 } else if (!rule->uid_op(cred->euid, rule->uid))
 540                         return false;
 541         }
 542
 543         if ((rule->flags & IMA_FOWNER) &&
 544             !rule->fowner_op(i_uid_into_mnt(mnt_userns, inode), rule->fowner))
 545                 return false;
 546         for (i = 0; i < MAX_LSM_RULES; i++) {
 547                 int rc = 0;
 548                 u32 osid;
 549
 550                 if (!rule->lsm[i].rule) {
 551                         if (!rule->lsm[i].args_p)
 552                                 continue;
 553                         else
 554                                 return false;
 555                 }
 556                 switch (i) {
 557                 case LSM_OBJ_USER:
 558                 case LSM_OBJ_ROLE:
 559                 case LSM_OBJ_TYPE:
 560                         security_inode_getsecid(inode, &osid);
 561                         rc = ima_filter_rule_match(osid, rule->lsm[i].type,
 562                                                    Audit_equal,
 563                                                    rule->lsm[i].rule);
 564                         break;
 565                 case LSM_SUBJ_USER:
 566                 case LSM_SUBJ_ROLE:
 567                 case LSM_SUBJ_TYPE:
 568                         rc = ima_filter_rule_match(secid, rule->lsm[i].type,
 569                                                    Audit_equal,
 570                                                    rule->lsm[i].rule);
 571                 default:
 572                         break;
 573                 }
 574                 if (!rc)
 575                         return false;
 576         }
 577         return true;
 578 }
 579
 580 /*
 581  * In addition to knowing that we need to appraise the file in general,
 582  * we need to differentiate between calling hooks, for hook specific rules.
 583  */
 584 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 585 {
 586         if (!(rule->flags & IMA_FUNC))
 587                 return IMA_FILE_APPRAISE;
 588
 589         switch (func) {
 590         case MMAP_CHECK:
 591                 return IMA_MMAP_APPRAISE;
 592         case BPRM_CHECK:
 593                 return IMA_BPRM_APPRAISE;
 594         case CREDS_CHECK:
 595                 return IMA_CREDS_APPRAISE;
 596         case FILE_CHECK:
 597         case POST_SETATTR:
 598                 return IMA_FILE_APPRAISE;
 599         case MODULE_CHECK ... MAX_CHECK - 1:
 600         default:
 601                 return IMA_READ_APPRAISE;
 602         }
 603 }
 604
 605 /**
 606  * ima_match_policy - decision based on LSM and other conditions
 607  * @mnt_userns: user namespace of the mount the inode was found from
 608  * @inode: pointer to an inode for which the policy decision is being made
 609  * @cred: pointer to a credentials structure for which the policy decision is
 610  *        being made
 611  * @secid: LSM secid of the task to be validated
 612  * @func: IMA hook identifier
 613  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 614  * @pcr: set the pcr to extend
 615  * @template_desc: the template that should be used for this rule
 616  * @keyring: the keyring name, if given, to be used to check in the policy.
 617  *           keyring can be NULL if func is anything other than KEY_CHECK.
 618  *
 619  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 620  * conditions.
 621  *
 622  * Since the IMA policy may be updated multiple times we need to lock the
 623  * list when walking it.  Reads are many orders of magnitude more numerous
 624  * than writes so ima_match_policy() is classical RCU candidate.
 625  */
 626 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 627                      const struct cred *cred, u32 secid, enum ima_hooks func,
 628                      int mask, int flags, int *pcr,
 629                      struct ima_template_desc **template_desc,
 630                      const char *keyring)
 631 {
 632         struct ima_rule_entry *entry;
 633         int action = 0, actmask = flags | (flags << 1);
 634
 635         if (template_desc && !*template_desc)
 636                 *template_desc = ima_template_desc_current();
 637
 638         rcu_read_lock();
 639         list_for_each_entry_rcu(entry, ima_rules, list) {
 640
 641                 if (!(entry->action & actmask))
 642                         continue;
 643
 644                 if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
 645                                      func, mask, keyring))
 646                         continue;
 647
 648                 action |= entry->flags & IMA_ACTION_FLAGS;
 649
 650                 action |= entry->action & IMA_DO_MASK;
 651                 if (entry->action & IMA_APPRAISE) {
 652                         action |= get_subaction(entry, func);
 653                         action &= ~IMA_HASH;
 654                         if (ima_fail_unverifiable_sigs)
 655                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 656                 }
 657
 658
 659                 if (entry->action & IMA_DO_MASK)
 660                         actmask &= ~(entry->action | entry->action << 1);
 661                 else
 662                         actmask &= ~(entry->action | entry->action >> 1);
 663
 664                 if ((pcr) && (entry->flags & IMA_PCR))
 665                         *pcr = entry->pcr;
 666
 667                 if (template_desc && entry->template)
 668                         *template_desc = entry->template;
 669
 670                 if (!actmask)
 671                         break;
 672         }
 673         rcu_read_unlock();
 674
 675         return action;
 676 }
 677
 678 /*
 679  * Initialize the ima_policy_flag variable based on the currently
 680  * loaded policy.  Based on this flag, the decision to short circuit
 681  * out of a function or not call the function in the first place
 682  * can be made earlier.
 683  */
 684 void ima_update_policy_flag(void)
 685 {
 686         struct ima_rule_entry *entry;
 687
 688         list_for_each_entry(entry, ima_rules, list) {
 689                 if (entry->action & IMA_DO_MASK)
 690                         ima_policy_flag |= entry->action;
 691         }
 692
 693         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 694         if (!ima_appraise)
 695                 ima_policy_flag &= ~IMA_APPRAISE;
 696 }
 697
 698 static int ima_appraise_flag(enum ima_hooks func)
 699 {
 700         if (func == MODULE_CHECK)
 701                 return IMA_APPRAISE_MODULES;
 702         else if (func == FIRMWARE_CHECK)
 703                 return IMA_APPRAISE_FIRMWARE;
 704         else if (func == POLICY_CHECK)
 705                 return IMA_APPRAISE_POLICY;
 706         else if (func == KEXEC_KERNEL_CHECK)
 707                 return IMA_APPRAISE_KEXEC;
 708         return 0;
 709 }
 710
 711 static void add_rules(struct ima_rule_entry *entries, int count,
 712                       enum policy_rule_list policy_rule)
 713 {
 714         int i = 0;
 715
 716         for (i = 0; i < count; i++) {
 717                 struct ima_rule_entry *entry;
 718
 719                 if (policy_rule & IMA_DEFAULT_POLICY)
 720                         list_add_tail(&entries[i].list, &ima_default_rules);
 721
 722                 if (policy_rule & IMA_CUSTOM_POLICY) {
 723                         entry = kmemdup(&entries[i], sizeof(*entry),
 724                                         GFP_KERNEL);
 725                         if (!entry)
 726                                 continue;
 727
 728                         list_add_tail(&entry->list, &ima_policy_rules);
 729                 }
 730                 if (entries[i].action == APPRAISE) {
 731                         if (entries != build_appraise_rules)
 732                                 temp_ima_appraise |=
 733                                         ima_appraise_flag(entries[i].func);
 734                         else
 735                                 build_ima_appraise |=
 736                                         ima_appraise_flag(entries[i].func);
 737                 }
 738         }
 739 }
 740
 741 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 742
 743 static int __init ima_init_arch_policy(void)
 744 {
 745         const char * const *arch_rules;
 746         const char * const *rules;
 747         int arch_entries = 0;
 748         int i = 0;
 749
 750         arch_rules = arch_get_ima_policy();
 751         if (!arch_rules)
 752                 return arch_entries;
 753
 754         /* Get number of rules */
 755         for (rules = arch_rules; *rules != NULL; rules++)
 756                 arch_entries++;
 757
 758         arch_policy_entry = kcalloc(arch_entries + 1,
 759                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 760         if (!arch_policy_entry)
 761                 return 0;
 762
 763         /* Convert each policy string rules to struct ima_rule_entry format */
 764         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 765                 char rule[255];
 766                 int result;
 767
 768                 result = strlcpy(rule, *rules, sizeof(rule));
 769
 770                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 771                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 772                 if (result) {
 773                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 774                                 rule);
 775                         memset(&arch_policy_entry[i], 0,
 776                                sizeof(*arch_policy_entry));
 777                         continue;
 778                 }
 779                 i++;
 780         }
 781         return i;
 782 }
 783
 784 /**
 785  * ima_init_policy - initialize the default measure rules.
 786  *
 787  * ima_rules points to either the ima_default_rules or the
 788  * the new ima_policy_rules.
 789  */
 790 void __init ima_init_policy(void)
 791 {
 792         int build_appraise_entries, arch_entries;
 793
 794         /* if !ima_policy, we load NO default rules */
 795         if (ima_policy)
 796                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 797                           IMA_DEFAULT_POLICY);
 798
 799         switch (ima_policy) {
 800         case ORIGINAL_TCB:
 801                 add_rules(original_measurement_rules,
 802                           ARRAY_SIZE(original_measurement_rules),
 803                           IMA_DEFAULT_POLICY);
 804                 break;
 805         case DEFAULT_TCB:
 806                 add_rules(default_measurement_rules,
 807                           ARRAY_SIZE(default_measurement_rules),
 808                           IMA_DEFAULT_POLICY);
 809         default:
 810                 break;
 811         }
 812
 813         /*
 814          * Based on runtime secure boot flags, insert arch specific measurement
 815          * and appraise rules requiring file signatures for both the initial
 816          * and custom policies, prior to other appraise rules.
 817          * (Highest priority)
 818          */
 819         arch_entries = ima_init_arch_policy();
 820         if (!arch_entries)
 821                 pr_info("No architecture policies found\n");
 822         else
 823                 add_rules(arch_policy_entry, arch_entries,
 824                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 825
 826         /*
 827          * Insert the builtin "secure_boot" policy rules requiring file
 828          * signatures, prior to other appraise rules.
 829          */
 830         if (ima_use_secure_boot)
 831                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 832                           IMA_DEFAULT_POLICY);
 833
 834         /*
 835          * Insert the build time appraise rules requiring file signatures
 836          * for both the initial and custom policies, prior to other appraise
 837          * rules. As the secure boot rules includes all of the build time
 838          * rules, include either one or the other set of rules, but not both.
 839          */
 840         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 841         if (build_appraise_entries) {
 842                 if (ima_use_secure_boot)
 843                         add_rules(build_appraise_rules, build_appraise_entries,
 844                                   IMA_CUSTOM_POLICY);
 845                 else
 846                         add_rules(build_appraise_rules, build_appraise_entries,
 847                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 848         }
 849
 850         if (ima_use_appraise_tcb)
 851                 add_rules(default_appraise_rules,
 852                           ARRAY_SIZE(default_appraise_rules),
 853                           IMA_DEFAULT_POLICY);
 854
 855         ima_update_policy_flag();
 856 }
 857
 858 /* Make sure we have a valid policy, at least containing some rules. */
 859 int ima_check_policy(void)
 860 {
 861         if (list_empty(&ima_temp_rules))
 862                 return -EINVAL;
 863         return 0;
 864 }
 865
 866 /**
 867  * ima_update_policy - update default_rules with new measure rules
 868  *
 869  * Called on file .release to update the default rules with a complete new
 870  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
 871  * they make a queue.  The policy may be updated multiple times and this is the
 872  * RCU updater.
 873  *
 874  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
 875  * we switch from the default policy to user defined.
 876  */
 877 void ima_update_policy(void)
 878 {
 879         struct list_head *policy = &ima_policy_rules;
 880
 881         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
 882
 883         if (ima_rules != policy) {
 884                 ima_policy_flag = 0;
 885                 ima_rules = policy;
 886
 887                 /*
 888                  * IMA architecture specific policy rules are specified
 889                  * as strings and converted to an array of ima_entry_rules
 890                  * on boot.  After loading a custom policy, free the
 891                  * architecture specific rules stored as an array.
 892                  */
 893                 kfree(arch_policy_entry);
 894         }
 895         ima_update_policy_flag();
 896
 897         /* Custom IMA policy has been loaded */
 898         ima_process_queued_keys();
 899 }
 900
 901 /* Keep the enumeration in sync with the policy_tokens! */
 902 enum {
 903         Opt_measure, Opt_dont_measure,
 904         Opt_appraise, Opt_dont_appraise,
 905         Opt_audit, Opt_hash, Opt_dont_hash,
 906         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 907         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 908         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
 909         Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
 910         Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 911         Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
 912         Opt_appraise_type, Opt_appraise_flag,
 913         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
 914         Opt_err
 915 };
 916
 917 static const match_table_t policy_tokens = {
 918         {Opt_measure, "measure"},
 919         {Opt_dont_measure, "dont_measure"},
 920         {Opt_appraise, "appraise"},
 921         {Opt_dont_appraise, "dont_appraise"},
 922         {Opt_audit, "audit"},
 923         {Opt_hash, "hash"},
 924         {Opt_dont_hash, "dont_hash"},
 925         {Opt_obj_user, "obj_user=%s"},
 926         {Opt_obj_role, "obj_role=%s"},
 927         {Opt_obj_type, "obj_type=%s"},
 928         {Opt_subj_user, "subj_user=%s"},
 929         {Opt_subj_role, "subj_role=%s"},
 930         {Opt_subj_type, "subj_type=%s"},
 931         {Opt_func, "func=%s"},
 932         {Opt_mask, "mask=%s"},
 933         {Opt_fsmagic, "fsmagic=%s"},
 934         {Opt_fsname, "fsname=%s"},
 935         {Opt_fsuuid, "fsuuid=%s"},
 936         {Opt_uid_eq, "uid=%s"},
 937         {Opt_euid_eq, "euid=%s"},
 938         {Opt_fowner_eq, "fowner=%s"},
 939         {Opt_uid_gt, "uid>%s"},
 940         {Opt_euid_gt, "euid>%s"},
 941         {Opt_fowner_gt, "fowner>%s"},
 942         {Opt_uid_lt, "uid<%s"},
 943         {Opt_euid_lt, "euid<%s"},
 944         {Opt_fowner_lt, "fowner<%s"},
 945         {Opt_appraise_type, "appraise_type=%s"},
 946         {Opt_appraise_flag, "appraise_flag=%s"},
 947         {Opt_permit_directio, "permit_directio"},
 948         {Opt_pcr, "pcr=%s"},
 949         {Opt_template, "template=%s"},
 950         {Opt_keyrings, "keyrings=%s"},
 951         {Opt_err, NULL}
 952 };
 953
 954 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 955                              substring_t *args, int lsm_rule, int audit_type)
 956 {
 957         int result;
 958
 959         if (entry->lsm[lsm_rule].rule)
 960                 return -EINVAL;
 961
 962         entry->lsm[lsm_rule].args_p = match_strdup(args);
 963         if (!entry->lsm[lsm_rule].args_p)
 964                 return -ENOMEM;
 965
 966         entry->lsm[lsm_rule].type = audit_type;
 967         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
 968                                       entry->lsm[lsm_rule].args_p,
 969                                       &entry->lsm[lsm_rule].rule);
 970         if (!entry->lsm[lsm_rule].rule) {
 971                 pr_warn("rule for LSM \'%s\' is undefined\n",
 972                         entry->lsm[lsm_rule].args_p);
 973
 974                 if (ima_rules == &ima_default_rules) {
 975                         kfree(entry->lsm[lsm_rule].args_p);
 976                         entry->lsm[lsm_rule].args_p = NULL;
 977                         result = -EINVAL;
 978                 } else
 979                         result = 0;
 980         }
 981
 982         return result;
 983 }
 984
 985 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
 986                               bool (*rule_operator)(kuid_t, kuid_t))
 987 {
 988         if (!ab)
 989                 return;
 990
 991         if (rule_operator == &uid_gt)
 992                 audit_log_format(ab, "%s>", key);
 993         else if (rule_operator == &uid_lt)
 994                 audit_log_format(ab, "%s<", key);
 995         else
 996                 audit_log_format(ab, "%s=", key);
 997         audit_log_format(ab, "%s ", value);
 998 }
 999 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1000 {
1001         ima_log_string_op(ab, key, value, NULL);
1002 }
1003
1004 /*
1005  * Validating the appended signature included in the measurement list requires
1006  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1007  * field). Therefore, notify the user if they have the 'modsig' field but not
1008  * the 'd-modsig' field in the template.
1009  */
1010 static void check_template_modsig(const struct ima_template_desc *template)
1011 {
1012 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1013         bool has_modsig, has_dmodsig;
1014         static bool checked;
1015         int i;
1016
1017         /* We only need to notify the user once. */
1018         if (checked)
1019                 return;
1020
1021         has_modsig = has_dmodsig = false;
1022         for (i = 0; i < template->num_fields; i++) {
1023                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1024                         has_modsig = true;
1025                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1026                         has_dmodsig = true;
1027         }
1028
1029         if (has_modsig && !has_dmodsig)
1030                 pr_notice(MSG);
1031
1032         checked = true;
1033 #undef MSG
1034 }
1035
1036 static bool ima_validate_rule(struct ima_rule_entry *entry)
1037 {
1038         /* Ensure that the action is set and is compatible with the flags */
1039         if (entry->action == UNKNOWN)
1040                 return false;
1041
1042         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1043                 return false;
1044
1045         if (entry->action != APPRAISE &&
1046             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
1047                 return false;
1048
1049         /*
1050          * The IMA_FUNC bit must be set if and only if there's a valid hook
1051          * function specified, and vice versa. Enforcing this property allows
1052          * for the NONE case below to validate a rule without an explicit hook
1053          * function.
1054          */
1055         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1056             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1057                 return false;
1058
1059         /*
1060          * Ensure that the hook function is compatible with the other
1061          * components of the rule
1062          */
1063         switch (entry->func) {
1064         case NONE:
1065         case FILE_CHECK:
1066         case MMAP_CHECK:
1067         case BPRM_CHECK:
1068         case CREDS_CHECK:
1069         case POST_SETATTR:
1070         case FIRMWARE_CHECK:
1071         case POLICY_CHECK:
1072                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1073                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1074                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1075                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1076                                      IMA_PERMIT_DIRECTIO))
1077                         return false;
1078
1079                 break;
1080         case MODULE_CHECK:
1081         case KEXEC_KERNEL_CHECK:
1082         case KEXEC_INITRAMFS_CHECK:
1083                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1084                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1085                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1086                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1087                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1088                                      IMA_CHECK_BLACKLIST))
1089                         return false;
1090
1091                 break;
1092         case KEXEC_CMDLINE:
1093                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1094                         return false;
1095
1096                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1097                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1098                                      IMA_PCR | IMA_FSNAME))
1099                         return false;
1100
1101                 break;
1102         case KEY_CHECK:
1103                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1104                         return false;
1105
1106                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1107                                      IMA_KEYRINGS))
1108                         return false;
1109
1110                 if (ima_rule_contains_lsm_cond(entry))
1111                         return false;
1112
1113                 break;
1114         default:
1115                 return false;
1116         }
1117
1118         /* Ensure that combinations of flags are compatible with each other */
1119         if (entry->flags & IMA_CHECK_BLACKLIST &&
1120             !(entry->flags & IMA_MODSIG_ALLOWED))
1121                 return false;
1122
1123         return true;
1124 }
1125
1126 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1127 {
1128         struct audit_buffer *ab;
1129         char *from;
1130         char *p;
1131         bool uid_token;
1132         struct ima_template_desc *template_desc;
1133         int result = 0;
1134
1135         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1136                                        AUDIT_INTEGRITY_POLICY_RULE);
1137
1138         entry->uid = INVALID_UID;
1139         entry->fowner = INVALID_UID;
1140         entry->uid_op = &uid_eq;
1141         entry->fowner_op = &uid_eq;
1142         entry->action = UNKNOWN;
1143         while ((p = strsep(&rule, " \t")) != NULL) {
1144                 substring_t args[MAX_OPT_ARGS];
1145                 int token;
1146                 unsigned long lnum;
1147
1148                 if (result < 0)
1149                         break;
1150                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1151                         continue;
1152                 token = match_token(p, policy_tokens, args);
1153                 switch (token) {
1154                 case Opt_measure:
1155                         ima_log_string(ab, "action", "measure");
1156
1157                         if (entry->action != UNKNOWN)
1158                                 result = -EINVAL;
1159
1160                         entry->action = MEASURE;
1161                         break;
1162                 case Opt_dont_measure:
1163                         ima_log_string(ab, "action", "dont_measure");
1164
1165                         if (entry->action != UNKNOWN)
1166                                 result = -EINVAL;
1167
1168                         entry->action = DONT_MEASURE;
1169                         break;
1170                 case Opt_appraise:
1171                         ima_log_string(ab, "action", "appraise");
1172
1173                         if (entry->action != UNKNOWN)
1174                                 result = -EINVAL;
1175
1176                         entry->action = APPRAISE;
1177                         break;
1178                 case Opt_dont_appraise:
1179                         ima_log_string(ab, "action", "dont_appraise");
1180
1181                         if (entry->action != UNKNOWN)
1182                                 result = -EINVAL;
1183
1184                         entry->action = DONT_APPRAISE;
1185                         break;
1186                 case Opt_audit:
1187                         ima_log_string(ab, "action", "audit");
1188
1189                         if (entry->action != UNKNOWN)
1190                                 result = -EINVAL;
1191
1192                         entry->action = AUDIT;
1193                         break;
1194                 case Opt_hash:
1195                         ima_log_string(ab, "action", "hash");
1196
1197                         if (entry->action != UNKNOWN)
1198                                 result = -EINVAL;
1199
1200                         entry->action = HASH;
1201                         break;
1202                 case Opt_dont_hash:
1203                         ima_log_string(ab, "action", "dont_hash");
1204
1205                         if (entry->action != UNKNOWN)
1206                                 result = -EINVAL;
1207
1208                         entry->action = DONT_HASH;
1209                         break;
1210                 case Opt_func:
1211                         ima_log_string(ab, "func", args[0].from);
1212
1213                         if (entry->func)
1214                                 result = -EINVAL;
1215
1216                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1217                                 entry->func = FILE_CHECK;
1218                         /* PATH_CHECK is for backwards compat */
1219                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1220                                 entry->func = FILE_CHECK;
1221                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1222                                 entry->func = MODULE_CHECK;
1223                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1224                                 entry->func = FIRMWARE_CHECK;
1225                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1226                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1227                                 entry->func = MMAP_CHECK;
1228                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1229                                 entry->func = BPRM_CHECK;
1230                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1231                                 entry->func = CREDS_CHECK;
1232                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1233                                  0)
1234                                 entry->func = KEXEC_KERNEL_CHECK;
1235                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1236                                  == 0)
1237                                 entry->func = KEXEC_INITRAMFS_CHECK;
1238                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1239                                 entry->func = POLICY_CHECK;
1240                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1241                                 entry->func = KEXEC_CMDLINE;
1242                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1243                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1244                                 entry->func = KEY_CHECK;
1245                         else
1246                                 result = -EINVAL;
1247                         if (!result)
1248                                 entry->flags |= IMA_FUNC;
1249                         break;
1250                 case Opt_mask:
1251                         ima_log_string(ab, "mask", args[0].from);
1252
1253                         if (entry->mask)
1254                                 result = -EINVAL;
1255
1256                         from = args[0].from;
1257                         if (*from == '^')
1258                                 from++;
1259
1260                         if ((strcmp(from, "MAY_EXEC")) == 0)
1261                                 entry->mask = MAY_EXEC;
1262                         else if (strcmp(from, "MAY_WRITE") == 0)
1263                                 entry->mask = MAY_WRITE;
1264                         else if (strcmp(from, "MAY_READ") == 0)
1265                                 entry->mask = MAY_READ;
1266                         else if (strcmp(from, "MAY_APPEND") == 0)
1267                                 entry->mask = MAY_APPEND;
1268                         else
1269                                 result = -EINVAL;
1270                         if (!result)
1271                                 entry->flags |= (*args[0].from == '^')
1272                                      ? IMA_INMASK : IMA_MASK;
1273                         break;
1274                 case Opt_fsmagic:
1275                         ima_log_string(ab, "fsmagic", args[0].from);
1276
1277                         if (entry->fsmagic) {
1278                                 result = -EINVAL;
1279                                 break;
1280                         }
1281
1282                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1283                         if (!result)
1284                                 entry->flags |= IMA_FSMAGIC;
1285                         break;
1286                 case Opt_fsname:
1287                         ima_log_string(ab, "fsname", args[0].from);
1288
1289                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1290                         if (!entry->fsname) {
1291                                 result = -ENOMEM;
1292                                 break;
1293                         }
1294                         result = 0;
1295                         entry->flags |= IMA_FSNAME;
1296                         break;
1297                 case Opt_keyrings:
1298                         ima_log_string(ab, "keyrings", args[0].from);
1299
1300                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1301                             entry->keyrings) {
1302                                 result = -EINVAL;
1303                                 break;
1304                         }
1305
1306                         entry->keyrings = ima_alloc_rule_opt_list(args);
1307                         if (IS_ERR(entry->keyrings)) {
1308                                 result = PTR_ERR(entry->keyrings);
1309                                 entry->keyrings = NULL;
1310                                 break;
1311                         }
1312
1313                         entry->flags |= IMA_KEYRINGS;
1314                         break;
1315                 case Opt_fsuuid:
1316                         ima_log_string(ab, "fsuuid", args[0].from);
1317
1318                         if (!uuid_is_null(&entry->fsuuid)) {
1319                                 result = -EINVAL;
1320                                 break;
1321                         }
1322
1323                         result = uuid_parse(args[0].from, &entry->fsuuid);
1324                         if (!result)
1325                                 entry->flags |= IMA_FSUUID;
1326                         break;
1327                 case Opt_uid_gt:
1328                 case Opt_euid_gt:
1329                         entry->uid_op = &uid_gt;
1330                         fallthrough;
1331                 case Opt_uid_lt:
1332                 case Opt_euid_lt:
1333                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1334                                 entry->uid_op = &uid_lt;
1335                         fallthrough;
1336                 case Opt_uid_eq:
1337                 case Opt_euid_eq:
1338                         uid_token = (token == Opt_uid_eq) ||
1339                                     (token == Opt_uid_gt) ||
1340                                     (token == Opt_uid_lt);
1341
1342                         ima_log_string_op(ab, uid_token ? "uid" : "euid",
1343                                           args[0].from, entry->uid_op);
1344
1345                         if (uid_valid(entry->uid)) {
1346                                 result = -EINVAL;
1347                                 break;
1348                         }
1349
1350                         result = kstrtoul(args[0].from, 10, &lnum);
1351                         if (!result) {
1352                                 entry->uid = make_kuid(current_user_ns(),
1353                                                        (uid_t) lnum);
1354                                 if (!uid_valid(entry->uid) ||
1355                                     (uid_t)lnum != lnum)
1356                                         result = -EINVAL;
1357                                 else
1358                                         entry->flags |= uid_token
1359                                             ? IMA_UID : IMA_EUID;
1360                         }
1361                         break;
1362                 case Opt_fowner_gt:
1363                         entry->fowner_op = &uid_gt;
1364                         fallthrough;
1365                 case Opt_fowner_lt:
1366                         if (token == Opt_fowner_lt)
1367                                 entry->fowner_op = &uid_lt;
1368                         fallthrough;
1369                 case Opt_fowner_eq:
1370                         ima_log_string_op(ab, "fowner", args[0].from,
1371                                           entry->fowner_op);
1372
1373                         if (uid_valid(entry->fowner)) {
1374                                 result = -EINVAL;
1375                                 break;
1376                         }
1377
1378                         result = kstrtoul(args[0].from, 10, &lnum);
1379                         if (!result) {
1380                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
1381                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
1382                                         result = -EINVAL;
1383                                 else
1384                                         entry->flags |= IMA_FOWNER;
1385                         }
1386                         break;
1387                 case Opt_obj_user:
1388                         ima_log_string(ab, "obj_user", args[0].from);
1389                         result = ima_lsm_rule_init(entry, args,
1390                                                    LSM_OBJ_USER,
1391                                                    AUDIT_OBJ_USER);
1392                         break;
1393                 case Opt_obj_role:
1394                         ima_log_string(ab, "obj_role", args[0].from);
1395                         result = ima_lsm_rule_init(entry, args,
1396                                                    LSM_OBJ_ROLE,
1397                                                    AUDIT_OBJ_ROLE);
1398                         break;
1399                 case Opt_obj_type:
1400                         ima_log_string(ab, "obj_type", args[0].from);
1401                         result = ima_lsm_rule_init(entry, args,
1402                                                    LSM_OBJ_TYPE,
1403                                                    AUDIT_OBJ_TYPE);
1404                         break;
1405                 case Opt_subj_user:
1406                         ima_log_string(ab, "subj_user", args[0].from);
1407                         result = ima_lsm_rule_init(entry, args,
1408                                                    LSM_SUBJ_USER,
1409                                                    AUDIT_SUBJ_USER);
1410                         break;
1411                 case Opt_subj_role:
1412                         ima_log_string(ab, "subj_role", args[0].from);
1413                         result = ima_lsm_rule_init(entry, args,
1414                                                    LSM_SUBJ_ROLE,
1415                                                    AUDIT_SUBJ_ROLE);
1416                         break;
1417                 case Opt_subj_type:
1418                         ima_log_string(ab, "subj_type", args[0].from);
1419                         result = ima_lsm_rule_init(entry, args,
1420                                                    LSM_SUBJ_TYPE,
1421                                                    AUDIT_SUBJ_TYPE);
1422                         break;
1423                 case Opt_appraise_type:
1424                         ima_log_string(ab, "appraise_type", args[0].from);
1425                         if ((strcmp(args[0].from, "imasig")) == 0)
1426                                 entry->flags |= IMA_DIGSIG_REQUIRED;
1427                         else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1428                                  strcmp(args[0].from, "imasig|modsig") == 0)
1429                                 entry->flags |= IMA_DIGSIG_REQUIRED |
1430                                                 IMA_MODSIG_ALLOWED;
1431                         else
1432                                 result = -EINVAL;
1433                         break;
1434                 case Opt_appraise_flag:
1435                         ima_log_string(ab, "appraise_flag", args[0].from);
1436                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1437                             strstr(args[0].from, "blacklist"))
1438                                 entry->flags |= IMA_CHECK_BLACKLIST;
1439                         else
1440                                 result = -EINVAL;
1441                         break;
1442                 case Opt_permit_directio:
1443                         entry->flags |= IMA_PERMIT_DIRECTIO;
1444                         break;
1445                 case Opt_pcr:
1446                         ima_log_string(ab, "pcr", args[0].from);
1447
1448                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1449                         if (result || INVALID_PCR(entry->pcr))
1450                                 result = -EINVAL;
1451                         else
1452                                 entry->flags |= IMA_PCR;
1453
1454                         break;
1455                 case Opt_template:
1456                         ima_log_string(ab, "template", args[0].from);
1457                         if (entry->action != MEASURE) {
1458                                 result = -EINVAL;
1459                                 break;
1460                         }
1461                         template_desc = lookup_template_desc(args[0].from);
1462                         if (!template_desc || entry->template) {
1463                                 result = -EINVAL;
1464                                 break;
1465                         }
1466
1467                         /*
1468                          * template_desc_init_fields() does nothing if
1469                          * the template is already initialised, so
1470                          * it's safe to do this unconditionally
1471                          */
1472                         template_desc_init_fields(template_desc->fmt,
1473                                                  &(template_desc->fields),
1474                                                  &(template_desc->num_fields));
1475                         entry->template = template_desc;
1476                         break;
1477                 case Opt_err:
1478                         ima_log_string(ab, "UNKNOWN", p);
1479                         result = -EINVAL;
1480                         break;
1481                 }
1482         }
1483         if (!result && !ima_validate_rule(entry))
1484                 result = -EINVAL;
1485         else if (entry->action == APPRAISE)
1486                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1487
1488         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1489                 template_desc = entry->template ? entry->template :
1490                                                   ima_template_desc_current();
1491                 check_template_modsig(template_desc);
1492         }
1493
1494         audit_log_format(ab, "res=%d", !result);
1495         audit_log_end(ab);
1496         return result;
1497 }
1498
1499 /**
1500  * ima_parse_add_rule - add a rule to ima_policy_rules
1501  * @rule - ima measurement policy rule
1502  *
1503  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1504  * Returns the length of the rule parsed, an error code on failure
1505  */
1506 ssize_t ima_parse_add_rule(char *rule)
1507 {
1508         static const char op[] = "update_policy";
1509         char *p;
1510         struct ima_rule_entry *entry;
1511         ssize_t result, len;
1512         int audit_info = 0;
1513
1514         p = strsep(&rule, "\n");
1515         len = strlen(p) + 1;
1516         p += strspn(p, " \t");
1517
1518         if (*p == '#' || *p == '\0')
1519                 return len;
1520
1521         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1522         if (!entry) {
1523                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1524                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1525                 return -ENOMEM;
1526         }
1527
1528         INIT_LIST_HEAD(&entry->list);
1529
1530         result = ima_parse_rule(p, entry);
1531         if (result) {
1532                 ima_free_rule(entry);
1533                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1534                                     NULL, op, "invalid-policy", result,
1535                                     audit_info);
1536                 return result;
1537         }
1538
1539         list_add_tail(&entry->list, &ima_temp_rules);
1540
1541         return len;
1542 }
1543
1544 /**
1545  * ima_delete_rules() called to cleanup invalid in-flight policy.
1546  * We don't need locking as we operate on the temp list, which is
1547  * different from the active one.  There is also only one user of
1548  * ima_delete_rules() at a time.
1549  */
1550 void ima_delete_rules(void)
1551 {
1552         struct ima_rule_entry *entry, *tmp;
1553
1554         temp_ima_appraise = 0;
1555         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1556                 list_del(&entry->list);
1557                 ima_free_rule(entry);
1558         }
1559 }
1560
1561 #define __ima_hook_stringify(func, str) (#func),
1562
1563 const char *const func_tokens[] = {
1564         __ima_hooks(__ima_hook_stringify)
1565 };
1566
1567 #ifdef  CONFIG_IMA_READ_POLICY
1568 enum {
1569         mask_exec = 0, mask_write, mask_read, mask_append
1570 };
1571
1572 static const char *const mask_tokens[] = {
1573         "^MAY_EXEC",
1574         "^MAY_WRITE",
1575         "^MAY_READ",
1576         "^MAY_APPEND"
1577 };
1578
1579 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1580 {
1581         loff_t l = *pos;
1582         struct ima_rule_entry *entry;
1583
1584         rcu_read_lock();
1585         list_for_each_entry_rcu(entry, ima_rules, list) {
1586                 if (!l--) {
1587                         rcu_read_unlock();
1588                         return entry;
1589                 }
1590         }
1591         rcu_read_unlock();
1592         return NULL;
1593 }
1594
1595 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1596 {
1597         struct ima_rule_entry *entry = v;
1598
1599         rcu_read_lock();
1600         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1601         rcu_read_unlock();
1602         (*pos)++;
1603
1604         return (&entry->list == ima_rules) ? NULL : entry;
1605 }
1606
1607 void ima_policy_stop(struct seq_file *m, void *v)
1608 {
1609 }
1610
1611 #define pt(token)       policy_tokens[token].pattern
1612 #define mt(token)       mask_tokens[token]
1613
1614 /*
1615  * policy_func_show - display the ima_hooks policy rule
1616  */
1617 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1618 {
1619         if (func > 0 && func < MAX_CHECK)
1620                 seq_printf(m, "func=%s ", func_tokens[func]);
1621         else
1622                 seq_printf(m, "func=%d ", func);
1623 }
1624
1625 static void ima_show_rule_opt_list(struct seq_file *m,
1626                                    const struct ima_rule_opt_list *opt_list)
1627 {
1628         size_t i;
1629
1630         for (i = 0; i < opt_list->count; i++)
1631                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
1632 }
1633
1634 int ima_policy_show(struct seq_file *m, void *v)
1635 {
1636         struct ima_rule_entry *entry = v;
1637         int i;
1638         char tbuf[64] = {0,};
1639         int offset = 0;
1640
1641         rcu_read_lock();
1642
1643         if (entry->action & MEASURE)
1644                 seq_puts(m, pt(Opt_measure));
1645         if (entry->action & DONT_MEASURE)
1646                 seq_puts(m, pt(Opt_dont_measure));
1647         if (entry->action & APPRAISE)
1648                 seq_puts(m, pt(Opt_appraise));
1649         if (entry->action & DONT_APPRAISE)
1650                 seq_puts(m, pt(Opt_dont_appraise));
1651         if (entry->action & AUDIT)
1652                 seq_puts(m, pt(Opt_audit));
1653         if (entry->action & HASH)
1654                 seq_puts(m, pt(Opt_hash));
1655         if (entry->action & DONT_HASH)
1656                 seq_puts(m, pt(Opt_dont_hash));
1657
1658         seq_puts(m, " ");
1659
1660         if (entry->flags & IMA_FUNC)
1661                 policy_func_show(m, entry->func);
1662
1663         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1664                 if (entry->flags & IMA_MASK)
1665                         offset = 1;
1666                 if (entry->mask & MAY_EXEC)
1667                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
1668                 if (entry->mask & MAY_WRITE)
1669                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
1670                 if (entry->mask & MAY_READ)
1671                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
1672                 if (entry->mask & MAY_APPEND)
1673                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
1674                 seq_puts(m, " ");
1675         }
1676
1677         if (entry->flags & IMA_FSMAGIC) {
1678                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
1679                 seq_printf(m, pt(Opt_fsmagic), tbuf);
1680                 seq_puts(m, " ");
1681         }
1682
1683         if (entry->flags & IMA_FSNAME) {
1684                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
1685                 seq_printf(m, pt(Opt_fsname), tbuf);
1686                 seq_puts(m, " ");
1687         }
1688
1689         if (entry->flags & IMA_KEYRINGS) {
1690                 seq_puts(m, "keyrings=");
1691                 ima_show_rule_opt_list(m, entry->keyrings);
1692                 seq_puts(m, " ");
1693         }
1694
1695         if (entry->flags & IMA_PCR) {
1696                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
1697                 seq_printf(m, pt(Opt_pcr), tbuf);
1698                 seq_puts(m, " ");
1699         }
1700
1701         if (entry->flags & IMA_FSUUID) {
1702                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
1703                 seq_puts(m, " ");
1704         }
1705
1706         if (entry->flags & IMA_UID) {
1707                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1708                 if (entry->uid_op == &uid_gt)
1709                         seq_printf(m, pt(Opt_uid_gt), tbuf);
1710                 else if (entry->uid_op == &uid_lt)
1711                         seq_printf(m, pt(Opt_uid_lt), tbuf);
1712                 else
1713                         seq_printf(m, pt(Opt_uid_eq), tbuf);
1714                 seq_puts(m, " ");
1715         }
1716
1717         if (entry->flags & IMA_EUID) {
1718                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1719                 if (entry->uid_op == &uid_gt)
1720                         seq_printf(m, pt(Opt_euid_gt), tbuf);
1721                 else if (entry->uid_op == &uid_lt)
1722                         seq_printf(m, pt(Opt_euid_lt), tbuf);
1723                 else
1724                         seq_printf(m, pt(Opt_euid_eq), tbuf);
1725                 seq_puts(m, " ");
1726         }
1727
1728         if (entry->flags & IMA_FOWNER) {
1729                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
1730                 if (entry->fowner_op == &uid_gt)
1731                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
1732                 else if (entry->fowner_op == &uid_lt)
1733                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
1734                 else
1735                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
1736                 seq_puts(m, " ");
1737         }
1738
1739         for (i = 0; i < MAX_LSM_RULES; i++) {
1740                 if (entry->lsm[i].rule) {
1741                         switch (i) {
1742                         case LSM_OBJ_USER:
1743                                 seq_printf(m, pt(Opt_obj_user),
1744                                            entry->lsm[i].args_p);
1745                                 break;
1746                         case LSM_OBJ_ROLE:
1747                                 seq_printf(m, pt(Opt_obj_role),
1748                                            entry->lsm[i].args_p);
1749                                 break;
1750                         case LSM_OBJ_TYPE:
1751                                 seq_printf(m, pt(Opt_obj_type),
1752                                            entry->lsm[i].args_p);
1753                                 break;
1754                         case LSM_SUBJ_USER:
1755                                 seq_printf(m, pt(Opt_subj_user),
1756                                            entry->lsm[i].args_p);
1757                                 break;
1758                         case LSM_SUBJ_ROLE:
1759                                 seq_printf(m, pt(Opt_subj_role),
1760                                            entry->lsm[i].args_p);
1761                                 break;
1762                         case LSM_SUBJ_TYPE:
1763                                 seq_printf(m, pt(Opt_subj_type),
1764                                            entry->lsm[i].args_p);
1765                                 break;
1766                         }
1767                         seq_puts(m, " ");
1768                 }
1769         }
1770         if (entry->template)
1771                 seq_printf(m, "template=%s ", entry->template->name);
1772         if (entry->flags & IMA_DIGSIG_REQUIRED) {
1773                 if (entry->flags & IMA_MODSIG_ALLOWED)
1774                         seq_puts(m, "appraise_type=imasig|modsig ");
1775                 else
1776                         seq_puts(m, "appraise_type=imasig ");
1777         }
1778         if (entry->flags & IMA_CHECK_BLACKLIST)
1779                 seq_puts(m, "appraise_flag=check_blacklist ");
1780         if (entry->flags & IMA_PERMIT_DIRECTIO)
1781                 seq_puts(m, "permit_directio ");
1782         rcu_read_unlock();
1783         seq_puts(m, "\n");
1784         return 0;
1785 }
1786 #endif  /* CONFIG_IMA_READ_POLICY */
1787
1788 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
1789 /*
1790  * ima_appraise_signature: whether IMA will appraise a given function using
1791  * an IMA digital signature. This is restricted to cases where the kernel
1792  * has a set of built-in trusted keys in order to avoid an attacker simply
1793  * loading additional keys.
1794  */
1795 bool ima_appraise_signature(enum kernel_read_file_id id)
1796 {
1797         struct ima_rule_entry *entry;
1798         bool found = false;
1799         enum ima_hooks func;
1800
1801         if (id >= READING_MAX_ID)
1802                 return false;
1803
1804         func = read_idmap[id] ?: FILE_CHECK;
1805
1806         rcu_read_lock();
1807         list_for_each_entry_rcu(entry, ima_rules, list) {
1808                 if (entry->action != APPRAISE)
1809                         continue;
1810
1811                 /*
1812                  * A generic entry will match, but otherwise require that it
1813                  * match the func we're looking for
1814                  */
1815                 if (entry->func && entry->func != func)
1816                         continue;
1817
1818                 /*
1819                  * We require this to be a digital signature, not a raw IMA
1820                  * hash.
1821                  */
1822                 if (entry->flags & IMA_DIGSIG_REQUIRED)
1823                         found = true;
1824
1825                 /*
1826                  * We've found a rule that matches, so break now even if it
1827                  * didn't require a digital signature - a later rule that does
1828                  * won't override it, so would be a false positive.
1829                  */
1830                 break;
1831         }
1832
1833         rcu_read_unlock();
1834         return found;
1835 }
1836 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */