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/seq_file.h>
  20 #include <linux/ima.h>
  21
  22 #include "ima.h"
  23
  24 /* flags definitions */
  25 #define IMA_FUNC        0x0001
  26 #define IMA_MASK        0x0002
  27 #define IMA_FSMAGIC     0x0004
  28 #define IMA_UID         0x0008
  29 #define IMA_FOWNER      0x0010
  30 #define IMA_FSUUID      0x0020
  31 #define IMA_INMASK      0x0040
  32 #define IMA_EUID        0x0080
  33 #define IMA_PCR         0x0100
  34 #define IMA_FSNAME      0x0200
  35 #define IMA_KEYRINGS    0x0400
  36 #define IMA_LABEL       0x0800
  37 #define IMA_VALIDATE_ALGOS      0x1000
  38 #define IMA_GID         0x2000
  39 #define IMA_EGID        0x4000
  40 #define IMA_FGROUP      0x8000
  41
  42 #define UNKNOWN         0
  43 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  44 #define DONT_MEASURE    0x0002
  45 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  46 #define DONT_APPRAISE   0x0008
  47 #define AUDIT           0x0040
  48 #define HASH            0x0100
  49 #define DONT_HASH       0x0200
  50
  51 #define INVALID_PCR(a) (((a) < 0) || \
  52         (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
  53
  54 int ima_policy_flag;
  55 static int temp_ima_appraise;
  56 static int build_ima_appraise __ro_after_init;
  57
  58 atomic_t ima_setxattr_allowed_hash_algorithms;
  59
  60 #define MAX_LSM_RULES 6
  61 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  62         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  63 };
  64
  65 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  66
  67 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
  68
  69 struct ima_rule_opt_list {
  70         size_t count;
  71         char *items[];
  72 };
  73
  74 struct ima_rule_entry {
  75         struct list_head list;
  76         int action;
  77         unsigned int flags;
  78         enum ima_hooks func;
  79         int mask;
  80         unsigned long fsmagic;
  81         uuid_t fsuuid;
  82         kuid_t uid;
  83         kgid_t gid;
  84         kuid_t fowner;
  85         kgid_t fgroup;
  86         bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
  87         bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
  88         bool (*fowner_op)(kuid_t cred_uid, kuid_t rule_uid); /* uid_eq(), uid_gt(), uid_lt() */
  89         bool (*fgroup_op)(kgid_t cred_gid, kgid_t rule_gid); /* gid_eq(), gid_gt(), gid_lt() */
  90         int pcr;
  91         unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
  92         struct {
  93                 void *rule;     /* LSM file metadata specific */
  94                 char *args_p;   /* audit value */
  95                 int type;       /* audit type */
  96         } lsm[MAX_LSM_RULES];
  97         char *fsname;
  98         struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
  99         struct ima_rule_opt_list *label; /* Measure data grouped under this label */
 100         struct ima_template_desc *template;
 101 };
 102
 103 /*
 104  * sanity check in case the kernels gains more hash algorithms that can
 105  * fit in an unsigned int
 106  */
 107 static_assert(
 108         8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
 109         "The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
 110
 111 /*
 112  * Without LSM specific knowledge, the default policy can only be
 113  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
 114  * .fowner, and .fgroup
 115  */
 116
 117 /*
 118  * The minimum rule set to allow for full TCB coverage.  Measures all files
 119  * opened or mmap for exec and everything read by root.  Dangerous because
 120  * normal users can easily run the machine out of memory simply building
 121  * and running executables.
 122  */
 123 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
 124         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 125         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 126         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 127         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 128         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 129         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 130         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 131         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 132         {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 133         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
 134          .flags = IMA_FSMAGIC},
 135         {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
 136          .flags = IMA_FSMAGIC},
 137         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 138         {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
 139 };
 140
 141 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
 142         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 143          .flags = IMA_FUNC | IMA_MASK},
 144         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 145          .flags = IMA_FUNC | IMA_MASK},
 146         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 147          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 148          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 149         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 150         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 151 };
 152
 153 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
 154         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 155          .flags = IMA_FUNC | IMA_MASK},
 156         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 157          .flags = IMA_FUNC | IMA_MASK},
 158         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 159          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 160          .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 161         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 162          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 163          .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 164         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 165         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 166         {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
 167 };
 168
 169 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
 170         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 171         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 172         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 173         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 174         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 175         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 176         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 177         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 178         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 179         {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 180         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 181         {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
 182         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 183         {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 184 #ifdef CONFIG_IMA_WRITE_POLICY
 185         {.action = APPRAISE, .func = POLICY_CHECK,
 186         .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 187 #endif
 188 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 189         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 190          .flags = IMA_FOWNER},
 191 #else
 192         /* force signature */
 193         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 194          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 195 #endif
 196 };
 197
 198 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 199 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
 200         {.action = APPRAISE, .func = MODULE_CHECK,
 201          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 202 #endif
 203 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
 204         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 205          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 206 #endif
 207 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
 208         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 209          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 210 #endif
 211 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
 212         {.action = APPRAISE, .func = POLICY_CHECK,
 213          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 214 #endif
 215 };
 216
 217 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 218         {.action = APPRAISE, .func = MODULE_CHECK,
 219          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 220         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 221          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 222         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 223          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 224         {.action = APPRAISE, .func = POLICY_CHECK,
 225          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 226 };
 227
 228 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
 229         {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
 230 };
 231
 232 /* An array of architecture specific rules */
 233 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 234
 235 static LIST_HEAD(ima_default_rules);
 236 static LIST_HEAD(ima_policy_rules);
 237 static LIST_HEAD(ima_temp_rules);
 238 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
 239
 240 static int ima_policy __initdata;
 241
 242 static int __init default_measure_policy_setup(char *str)
 243 {
 244         if (ima_policy)
 245                 return 1;
 246
 247         ima_policy = ORIGINAL_TCB;
 248         return 1;
 249 }
 250 __setup("ima_tcb", default_measure_policy_setup);
 251
 252 static bool ima_use_appraise_tcb __initdata;
 253 static bool ima_use_secure_boot __initdata;
 254 static bool ima_use_critical_data __initdata;
 255 static bool ima_fail_unverifiable_sigs __ro_after_init;
 256 static int __init policy_setup(char *str)
 257 {
 258         char *p;
 259
 260         while ((p = strsep(&str, " |\n")) != NULL) {
 261                 if (*p == ' ')
 262                         continue;
 263                 if ((strcmp(p, "tcb") == 0) && !ima_policy)
 264                         ima_policy = DEFAULT_TCB;
 265                 else if (strcmp(p, "appraise_tcb") == 0)
 266                         ima_use_appraise_tcb = true;
 267                 else if (strcmp(p, "secure_boot") == 0)
 268                         ima_use_secure_boot = true;
 269                 else if (strcmp(p, "critical_data") == 0)
 270                         ima_use_critical_data = true;
 271                 else if (strcmp(p, "fail_securely") == 0)
 272                         ima_fail_unverifiable_sigs = true;
 273                 else
 274                         pr_err("policy \"%s\" not found", p);
 275         }
 276
 277         return 1;
 278 }
 279 __setup("ima_policy=", policy_setup);
 280
 281 static int __init default_appraise_policy_setup(char *str)
 282 {
 283         ima_use_appraise_tcb = true;
 284         return 1;
 285 }
 286 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 287
 288 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 289 {
 290         struct ima_rule_opt_list *opt_list;
 291         size_t count = 0;
 292         char *src_copy;
 293         char *cur, *next;
 294         size_t i;
 295
 296         src_copy = match_strdup(src);
 297         if (!src_copy)
 298                 return ERR_PTR(-ENOMEM);
 299
 300         next = src_copy;
 301         while ((cur = strsep(&next, "|"))) {
 302                 /* Don't accept an empty list item */
 303                 if (!(*cur)) {
 304                         kfree(src_copy);
 305                         return ERR_PTR(-EINVAL);
 306                 }
 307                 count++;
 308         }
 309
 310         /* Don't accept an empty list */
 311         if (!count) {
 312                 kfree(src_copy);
 313                 return ERR_PTR(-EINVAL);
 314         }
 315
 316         opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
 317         if (!opt_list) {
 318                 kfree(src_copy);
 319                 return ERR_PTR(-ENOMEM);
 320         }
 321
 322         /*
 323          * strsep() has already replaced all instances of '|' with '\0',
 324          * leaving a byte sequence of NUL-terminated strings. Reference each
 325          * string with the array of items.
 326          *
 327          * IMPORTANT: Ownership of the allocated buffer is transferred from
 328          * src_copy to the first element in the items array. To free the
 329          * buffer, kfree() must only be called on the first element of the
 330          * array.
 331          */
 332         for (i = 0, cur = src_copy; i < count; i++) {
 333                 opt_list->items[i] = cur;
 334                 cur = strchr(cur, '\0') + 1;
 335         }
 336         opt_list->count = count;
 337
 338         return opt_list;
 339 }
 340
 341 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 342 {
 343         if (!opt_list)
 344                 return;
 345
 346         if (opt_list->count) {
 347                 kfree(opt_list->items[0]);
 348                 opt_list->count = 0;
 349         }
 350
 351         kfree(opt_list);
 352 }
 353
 354 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 355 {
 356         int i;
 357
 358         for (i = 0; i < MAX_LSM_RULES; i++) {
 359                 ima_filter_rule_free(entry->lsm[i].rule);
 360                 kfree(entry->lsm[i].args_p);
 361         }
 362 }
 363
 364 static void ima_free_rule(struct ima_rule_entry *entry)
 365 {
 366         if (!entry)
 367                 return;
 368
 369         /*
 370          * entry->template->fields may be allocated in ima_parse_rule() but that
 371          * reference is owned by the corresponding ima_template_desc element in
 372          * the defined_templates list and cannot be freed here
 373          */
 374         kfree(entry->fsname);
 375         ima_free_rule_opt_list(entry->keyrings);
 376         ima_lsm_free_rule(entry);
 377         kfree(entry);
 378 }
 379
 380 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 381 {
 382         struct ima_rule_entry *nentry;
 383         int i;
 384
 385         /*
 386          * Immutable elements are copied over as pointers and data; only
 387          * lsm rules can change
 388          */
 389         nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
 390         if (!nentry)
 391                 return NULL;
 392
 393         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 394
 395         for (i = 0; i < MAX_LSM_RULES; i++) {
 396                 if (!entry->lsm[i].args_p)
 397                         continue;
 398
 399                 nentry->lsm[i].type = entry->lsm[i].type;
 400                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 401
 402                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 403                                      nentry->lsm[i].args_p,
 404                                      &nentry->lsm[i].rule);
 405                 if (!nentry->lsm[i].rule)
 406                         pr_warn("rule for LSM \'%s\' is undefined\n",
 407                                 nentry->lsm[i].args_p);
 408         }
 409         return nentry;
 410 }
 411
 412 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 413 {
 414         int i;
 415         struct ima_rule_entry *nentry;
 416
 417         nentry = ima_lsm_copy_rule(entry);
 418         if (!nentry)
 419                 return -ENOMEM;
 420
 421         list_replace_rcu(&entry->list, &nentry->list);
 422         synchronize_rcu();
 423         /*
 424          * ima_lsm_copy_rule() shallow copied all references, except for the
 425          * LSM references, from entry to nentry so we only want to free the LSM
 426          * references and the entry itself. All other memory references will now
 427          * be owned by nentry.
 428          */
 429         for (i = 0; i < MAX_LSM_RULES; i++)
 430                 ima_filter_rule_free(entry->lsm[i].rule);
 431         kfree(entry);
 432
 433         return 0;
 434 }
 435
 436 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 437 {
 438         int i;
 439
 440         for (i = 0; i < MAX_LSM_RULES; i++)
 441                 if (entry->lsm[i].args_p)
 442                         return true;
 443
 444         return false;
 445 }
 446
 447 /*
 448  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 449  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 450  * the reloaded LSM policy.
 451  */
 452 static void ima_lsm_update_rules(void)
 453 {
 454         struct ima_rule_entry *entry, *e;
 455         int result;
 456
 457         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 458                 if (!ima_rule_contains_lsm_cond(entry))
 459                         continue;
 460
 461                 result = ima_lsm_update_rule(entry);
 462                 if (result) {
 463                         pr_err("lsm rule update error %d\n", result);
 464                         return;
 465                 }
 466         }
 467 }
 468
 469 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 470                           void *lsm_data)
 471 {
 472         if (event != LSM_POLICY_CHANGE)
 473                 return NOTIFY_DONE;
 474
 475         ima_lsm_update_rules();
 476         return NOTIFY_OK;
 477 }
 478
 479 /**
 480  * ima_match_rule_data - determine whether func_data matches the policy rule
 481  * @rule: a pointer to a rule
 482  * @func_data: data to match against the measure rule data
 483  * @cred: a pointer to a credentials structure for user validation
 484  *
 485  * Returns true if func_data matches one in the rule, false otherwise.
 486  */
 487 static bool ima_match_rule_data(struct ima_rule_entry *rule,
 488                                 const char *func_data,
 489                                 const struct cred *cred)
 490 {
 491         const struct ima_rule_opt_list *opt_list = NULL;
 492         bool matched = false;
 493         size_t i;
 494
 495         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 496                 return false;
 497
 498         switch (rule->func) {
 499         case KEY_CHECK:
 500                 if (!rule->keyrings)
 501                         return true;
 502
 503                 opt_list = rule->keyrings;
 504                 break;
 505         case CRITICAL_DATA:
 506                 if (!rule->label)
 507                         return true;
 508
 509                 opt_list = rule->label;
 510                 break;
 511         default:
 512                 return false;
 513         }
 514
 515         if (!func_data)
 516                 return false;
 517
 518         for (i = 0; i < opt_list->count; i++) {
 519                 if (!strcmp(opt_list->items[i], func_data)) {
 520                         matched = true;
 521                         break;
 522                 }
 523         }
 524
 525         return matched;
 526 }
 527
 528 /**
 529  * ima_match_rules - determine whether an inode matches the policy rule.
 530  * @rule: a pointer to a rule
 531  * @mnt_userns: user namespace of the mount the inode was found from
 532  * @inode: a pointer to an inode
 533  * @cred: a pointer to a credentials structure for user validation
 534  * @secid: the secid of the task to be validated
 535  * @func: LIM hook identifier
 536  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 537  * @func_data: func specific data, may be NULL
 538  *
 539  * Returns true on rule match, false on failure.
 540  */
 541 static bool ima_match_rules(struct ima_rule_entry *rule,
 542                             struct user_namespace *mnt_userns,
 543                             struct inode *inode, const struct cred *cred,
 544                             u32 secid, enum ima_hooks func, int mask,
 545                             const char *func_data)
 546 {
 547         int i;
 548         bool result = false;
 549         struct ima_rule_entry *lsm_rule = rule;
 550         bool rule_reinitialized = false;
 551
 552         if ((rule->flags & IMA_FUNC) &&
 553             (rule->func != func && func != POST_SETATTR))
 554                 return false;
 555
 556         switch (func) {
 557         case KEY_CHECK:
 558         case CRITICAL_DATA:
 559                 return ((rule->func == func) &&
 560                         ima_match_rule_data(rule, func_data, cred));
 561         default:
 562                 break;
 563         }
 564
 565         if ((rule->flags & IMA_MASK) &&
 566             (rule->mask != mask && func != POST_SETATTR))
 567                 return false;
 568         if ((rule->flags & IMA_INMASK) &&
 569             (!(rule->mask & mask) && func != POST_SETATTR))
 570                 return false;
 571         if ((rule->flags & IMA_FSMAGIC)
 572             && rule->fsmagic != inode->i_sb->s_magic)
 573                 return false;
 574         if ((rule->flags & IMA_FSNAME)
 575             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 576                 return false;
 577         if ((rule->flags & IMA_FSUUID) &&
 578             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 579                 return false;
 580         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 581                 return false;
 582         if (rule->flags & IMA_EUID) {
 583                 if (has_capability_noaudit(current, CAP_SETUID)) {
 584                         if (!rule->uid_op(cred->euid, rule->uid)
 585                             && !rule->uid_op(cred->suid, rule->uid)
 586                             && !rule->uid_op(cred->uid, rule->uid))
 587                                 return false;
 588                 } else if (!rule->uid_op(cred->euid, rule->uid))
 589                         return false;
 590         }
 591         if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
 592                 return false;
 593         if (rule->flags & IMA_EGID) {
 594                 if (has_capability_noaudit(current, CAP_SETGID)) {
 595                         if (!rule->gid_op(cred->egid, rule->gid)
 596                             && !rule->gid_op(cred->sgid, rule->gid)
 597                             && !rule->gid_op(cred->gid, rule->gid))
 598                                 return false;
 599                 } else if (!rule->gid_op(cred->egid, rule->gid))
 600                         return false;
 601         }
 602         if ((rule->flags & IMA_FOWNER) &&
 603             !rule->fowner_op(i_uid_into_mnt(mnt_userns, inode), rule->fowner))
 604                 return false;
 605         if ((rule->flags & IMA_FGROUP) &&
 606             !rule->fgroup_op(i_gid_into_mnt(mnt_userns, inode), rule->fgroup))
 607                 return false;
 608         for (i = 0; i < MAX_LSM_RULES; i++) {
 609                 int rc = 0;
 610                 u32 osid;
 611
 612                 if (!lsm_rule->lsm[i].rule) {
 613                         if (!lsm_rule->lsm[i].args_p)
 614                                 continue;
 615                         else
 616                                 return false;
 617                 }
 618
 619 retry:
 620                 switch (i) {
 621                 case LSM_OBJ_USER:
 622                 case LSM_OBJ_ROLE:
 623                 case LSM_OBJ_TYPE:
 624                         security_inode_getsecid(inode, &osid);
 625                         rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
 626                                                    Audit_equal,
 627                                                    lsm_rule->lsm[i].rule);
 628                         break;
 629                 case LSM_SUBJ_USER:
 630                 case LSM_SUBJ_ROLE:
 631                 case LSM_SUBJ_TYPE:
 632                         rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
 633                                                    Audit_equal,
 634                                                    lsm_rule->lsm[i].rule);
 635                         break;
 636                 default:
 637                         break;
 638                 }
 639
 640                 if (rc == -ESTALE && !rule_reinitialized) {
 641                         lsm_rule = ima_lsm_copy_rule(rule);
 642                         if (lsm_rule) {
 643                                 rule_reinitialized = true;
 644                                 goto retry;
 645                         }
 646                 }
 647                 if (!rc) {
 648                         result = false;
 649                         goto out;
 650                 }
 651         }
 652         result = true;
 653
 654 out:
 655         if (rule_reinitialized) {
 656                 for (i = 0; i < MAX_LSM_RULES; i++)
 657                         ima_filter_rule_free(lsm_rule->lsm[i].rule);
 658                 kfree(lsm_rule);
 659         }
 660         return result;
 661 }
 662
 663 /*
 664  * In addition to knowing that we need to appraise the file in general,
 665  * we need to differentiate between calling hooks, for hook specific rules.
 666  */
 667 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 668 {
 669         if (!(rule->flags & IMA_FUNC))
 670                 return IMA_FILE_APPRAISE;
 671
 672         switch (func) {
 673         case MMAP_CHECK:
 674                 return IMA_MMAP_APPRAISE;
 675         case BPRM_CHECK:
 676                 return IMA_BPRM_APPRAISE;
 677         case CREDS_CHECK:
 678                 return IMA_CREDS_APPRAISE;
 679         case FILE_CHECK:
 680         case POST_SETATTR:
 681                 return IMA_FILE_APPRAISE;
 682         case MODULE_CHECK ... MAX_CHECK - 1:
 683         default:
 684                 return IMA_READ_APPRAISE;
 685         }
 686 }
 687
 688 /**
 689  * ima_match_policy - decision based on LSM and other conditions
 690  * @mnt_userns: user namespace of the mount the inode was found from
 691  * @inode: pointer to an inode for which the policy decision is being made
 692  * @cred: pointer to a credentials structure for which the policy decision is
 693  *        being made
 694  * @secid: LSM secid of the task to be validated
 695  * @func: IMA hook identifier
 696  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 697  * @pcr: set the pcr to extend
 698  * @template_desc: the template that should be used for this rule
 699  * @func_data: func specific data, may be NULL
 700  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
 701  *
 702  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 703  * conditions.
 704  *
 705  * Since the IMA policy may be updated multiple times we need to lock the
 706  * list when walking it.  Reads are many orders of magnitude more numerous
 707  * than writes so ima_match_policy() is classical RCU candidate.
 708  */
 709 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 710                      const struct cred *cred, u32 secid, enum ima_hooks func,
 711                      int mask, int flags, int *pcr,
 712                      struct ima_template_desc **template_desc,
 713                      const char *func_data, unsigned int *allowed_algos)
 714 {
 715         struct ima_rule_entry *entry;
 716         int action = 0, actmask = flags | (flags << 1);
 717         struct list_head *ima_rules_tmp;
 718
 719         if (template_desc && !*template_desc)
 720                 *template_desc = ima_template_desc_current();
 721
 722         rcu_read_lock();
 723         ima_rules_tmp = rcu_dereference(ima_rules);
 724         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 725
 726                 if (!(entry->action & actmask))
 727                         continue;
 728
 729                 if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
 730                                      func, mask, func_data))
 731                         continue;
 732
 733                 action |= entry->flags & IMA_NONACTION_FLAGS;
 734
 735                 action |= entry->action & IMA_DO_MASK;
 736                 if (entry->action & IMA_APPRAISE) {
 737                         action |= get_subaction(entry, func);
 738                         action &= ~IMA_HASH;
 739                         if (ima_fail_unverifiable_sigs)
 740                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 741
 742                         if (allowed_algos &&
 743                             entry->flags & IMA_VALIDATE_ALGOS)
 744                                 *allowed_algos = entry->allowed_algos;
 745                 }
 746
 747                 if (entry->action & IMA_DO_MASK)
 748                         actmask &= ~(entry->action | entry->action << 1);
 749                 else
 750                         actmask &= ~(entry->action | entry->action >> 1);
 751
 752                 if ((pcr) && (entry->flags & IMA_PCR))
 753                         *pcr = entry->pcr;
 754
 755                 if (template_desc && entry->template)
 756                         *template_desc = entry->template;
 757
 758                 if (!actmask)
 759                         break;
 760         }
 761         rcu_read_unlock();
 762
 763         return action;
 764 }
 765
 766 /**
 767  * ima_update_policy_flags() - Update global IMA variables
 768  *
 769  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
 770  * based on the currently loaded policy.
 771  *
 772  * With ima_policy_flag, the decision to short circuit out of a function
 773  * or not call the function in the first place can be made earlier.
 774  *
 775  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
 776  * set of hash algorithms accepted when updating the security.ima xattr of
 777  * a file.
 778  *
 779  * Context: called after a policy update and at system initialization.
 780  */
 781 void ima_update_policy_flags(void)
 782 {
 783         struct ima_rule_entry *entry;
 784         int new_policy_flag = 0;
 785         struct list_head *ima_rules_tmp;
 786
 787         rcu_read_lock();
 788         ima_rules_tmp = rcu_dereference(ima_rules);
 789         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 790                 /*
 791                  * SETXATTR_CHECK rules do not implement a full policy check
 792                  * because rule checking would probably have an important
 793                  * performance impact on setxattr(). As a consequence, only one
 794                  * SETXATTR_CHECK can be active at a given time.
 795                  * Because we want to preserve that property, we set out to use
 796                  * atomic_cmpxchg. Either:
 797                  * - the atomic was non-zero: a setxattr hash policy is
 798                  *   already enforced, we do nothing
 799                  * - the atomic was zero: no setxattr policy was set, enable
 800                  *   the setxattr hash policy
 801                  */
 802                 if (entry->func == SETXATTR_CHECK) {
 803                         atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
 804                                        0, entry->allowed_algos);
 805                         /* SETXATTR_CHECK doesn't impact ima_policy_flag */
 806                         continue;
 807                 }
 808
 809                 if (entry->action & IMA_DO_MASK)
 810                         new_policy_flag |= entry->action;
 811         }
 812         rcu_read_unlock();
 813
 814         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 815         if (!ima_appraise)
 816                 new_policy_flag &= ~IMA_APPRAISE;
 817
 818         ima_policy_flag = new_policy_flag;
 819 }
 820
 821 static int ima_appraise_flag(enum ima_hooks func)
 822 {
 823         if (func == MODULE_CHECK)
 824                 return IMA_APPRAISE_MODULES;
 825         else if (func == FIRMWARE_CHECK)
 826                 return IMA_APPRAISE_FIRMWARE;
 827         else if (func == POLICY_CHECK)
 828                 return IMA_APPRAISE_POLICY;
 829         else if (func == KEXEC_KERNEL_CHECK)
 830                 return IMA_APPRAISE_KEXEC;
 831         return 0;
 832 }
 833
 834 static void add_rules(struct ima_rule_entry *entries, int count,
 835                       enum policy_rule_list policy_rule)
 836 {
 837         int i = 0;
 838
 839         for (i = 0; i < count; i++) {
 840                 struct ima_rule_entry *entry;
 841
 842                 if (policy_rule & IMA_DEFAULT_POLICY)
 843                         list_add_tail(&entries[i].list, &ima_default_rules);
 844
 845                 if (policy_rule & IMA_CUSTOM_POLICY) {
 846                         entry = kmemdup(&entries[i], sizeof(*entry),
 847                                         GFP_KERNEL);
 848                         if (!entry)
 849                                 continue;
 850
 851                         list_add_tail(&entry->list, &ima_policy_rules);
 852                 }
 853                 if (entries[i].action == APPRAISE) {
 854                         if (entries != build_appraise_rules)
 855                                 temp_ima_appraise |=
 856                                         ima_appraise_flag(entries[i].func);
 857                         else
 858                                 build_ima_appraise |=
 859                                         ima_appraise_flag(entries[i].func);
 860                 }
 861         }
 862 }
 863
 864 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 865
 866 static int __init ima_init_arch_policy(void)
 867 {
 868         const char * const *arch_rules;
 869         const char * const *rules;
 870         int arch_entries = 0;
 871         int i = 0;
 872
 873         arch_rules = arch_get_ima_policy();
 874         if (!arch_rules)
 875                 return arch_entries;
 876
 877         /* Get number of rules */
 878         for (rules = arch_rules; *rules != NULL; rules++)
 879                 arch_entries++;
 880
 881         arch_policy_entry = kcalloc(arch_entries + 1,
 882                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 883         if (!arch_policy_entry)
 884                 return 0;
 885
 886         /* Convert each policy string rules to struct ima_rule_entry format */
 887         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 888                 char rule[255];
 889                 int result;
 890
 891                 result = strscpy(rule, *rules, sizeof(rule));
 892
 893                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 894                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 895                 if (result) {
 896                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 897                                 rule);
 898                         memset(&arch_policy_entry[i], 0,
 899                                sizeof(*arch_policy_entry));
 900                         continue;
 901                 }
 902                 i++;
 903         }
 904         return i;
 905 }
 906
 907 /**
 908  * ima_init_policy - initialize the default measure rules.
 909  *
 910  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
 911  */
 912 void __init ima_init_policy(void)
 913 {
 914         int build_appraise_entries, arch_entries;
 915
 916         /* if !ima_policy, we load NO default rules */
 917         if (ima_policy)
 918                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 919                           IMA_DEFAULT_POLICY);
 920
 921         switch (ima_policy) {
 922         case ORIGINAL_TCB:
 923                 add_rules(original_measurement_rules,
 924                           ARRAY_SIZE(original_measurement_rules),
 925                           IMA_DEFAULT_POLICY);
 926                 break;
 927         case DEFAULT_TCB:
 928                 add_rules(default_measurement_rules,
 929                           ARRAY_SIZE(default_measurement_rules),
 930                           IMA_DEFAULT_POLICY);
 931                 break;
 932         default:
 933                 break;
 934         }
 935
 936         /*
 937          * Based on runtime secure boot flags, insert arch specific measurement
 938          * and appraise rules requiring file signatures for both the initial
 939          * and custom policies, prior to other appraise rules.
 940          * (Highest priority)
 941          */
 942         arch_entries = ima_init_arch_policy();
 943         if (!arch_entries)
 944                 pr_info("No architecture policies found\n");
 945         else
 946                 add_rules(arch_policy_entry, arch_entries,
 947                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 948
 949         /*
 950          * Insert the builtin "secure_boot" policy rules requiring file
 951          * signatures, prior to other appraise rules.
 952          */
 953         if (ima_use_secure_boot)
 954                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 955                           IMA_DEFAULT_POLICY);
 956
 957         /*
 958          * Insert the build time appraise rules requiring file signatures
 959          * for both the initial and custom policies, prior to other appraise
 960          * rules. As the secure boot rules includes all of the build time
 961          * rules, include either one or the other set of rules, but not both.
 962          */
 963         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 964         if (build_appraise_entries) {
 965                 if (ima_use_secure_boot)
 966                         add_rules(build_appraise_rules, build_appraise_entries,
 967                                   IMA_CUSTOM_POLICY);
 968                 else
 969                         add_rules(build_appraise_rules, build_appraise_entries,
 970                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 971         }
 972
 973         if (ima_use_appraise_tcb)
 974                 add_rules(default_appraise_rules,
 975                           ARRAY_SIZE(default_appraise_rules),
 976                           IMA_DEFAULT_POLICY);
 977
 978         if (ima_use_critical_data)
 979                 add_rules(critical_data_rules,
 980                           ARRAY_SIZE(critical_data_rules),
 981                           IMA_DEFAULT_POLICY);
 982
 983         atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
 984
 985         ima_update_policy_flags();
 986 }
 987
 988 /* Make sure we have a valid policy, at least containing some rules. */
 989 int ima_check_policy(void)
 990 {
 991         if (list_empty(&ima_temp_rules))
 992                 return -EINVAL;
 993         return 0;
 994 }
 995
 996 /**
 997  * ima_update_policy - update default_rules with new measure rules
 998  *
 999  * Called on file .release to update the default rules with a complete new
1000  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
1001  * they make a queue.  The policy may be updated multiple times and this is the
1002  * RCU updater.
1003  *
1004  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
1005  * we switch from the default policy to user defined.
1006  */
1007 void ima_update_policy(void)
1008 {
1009         struct list_head *policy = &ima_policy_rules;
1010
1011         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
1012
1013         if (ima_rules != (struct list_head __rcu *)policy) {
1014                 ima_policy_flag = 0;
1015
1016                 rcu_assign_pointer(ima_rules, policy);
1017                 /*
1018                  * IMA architecture specific policy rules are specified
1019                  * as strings and converted to an array of ima_entry_rules
1020                  * on boot.  After loading a custom policy, free the
1021                  * architecture specific rules stored as an array.
1022                  */
1023                 kfree(arch_policy_entry);
1024         }
1025         ima_update_policy_flags();
1026
1027         /* Custom IMA policy has been loaded */
1028         ima_process_queued_keys();
1029 }
1030
1031 /* Keep the enumeration in sync with the policy_tokens! */
1032 enum policy_opt {
1033         Opt_measure, Opt_dont_measure,
1034         Opt_appraise, Opt_dont_appraise,
1035         Opt_audit, Opt_hash, Opt_dont_hash,
1036         Opt_obj_user, Opt_obj_role, Opt_obj_type,
1037         Opt_subj_user, Opt_subj_role, Opt_subj_type,
1038         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1039         Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1040         Opt_fowner_eq, Opt_fgroup_eq,
1041         Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1042         Opt_fowner_gt, Opt_fgroup_gt,
1043         Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1044         Opt_fowner_lt, Opt_fgroup_lt,
1045         Opt_digest_type,
1046         Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1047         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1048         Opt_label, Opt_err
1049 };
1050
1051 static const match_table_t policy_tokens = {
1052         {Opt_measure, "measure"},
1053         {Opt_dont_measure, "dont_measure"},
1054         {Opt_appraise, "appraise"},
1055         {Opt_dont_appraise, "dont_appraise"},
1056         {Opt_audit, "audit"},
1057         {Opt_hash, "hash"},
1058         {Opt_dont_hash, "dont_hash"},
1059         {Opt_obj_user, "obj_user=%s"},
1060         {Opt_obj_role, "obj_role=%s"},
1061         {Opt_obj_type, "obj_type=%s"},
1062         {Opt_subj_user, "subj_user=%s"},
1063         {Opt_subj_role, "subj_role=%s"},
1064         {Opt_subj_type, "subj_type=%s"},
1065         {Opt_func, "func=%s"},
1066         {Opt_mask, "mask=%s"},
1067         {Opt_fsmagic, "fsmagic=%s"},
1068         {Opt_fsname, "fsname=%s"},
1069         {Opt_fsuuid, "fsuuid=%s"},
1070         {Opt_uid_eq, "uid=%s"},
1071         {Opt_euid_eq, "euid=%s"},
1072         {Opt_gid_eq, "gid=%s"},
1073         {Opt_egid_eq, "egid=%s"},
1074         {Opt_fowner_eq, "fowner=%s"},
1075         {Opt_fgroup_eq, "fgroup=%s"},
1076         {Opt_uid_gt, "uid>%s"},
1077         {Opt_euid_gt, "euid>%s"},
1078         {Opt_gid_gt, "gid>%s"},
1079         {Opt_egid_gt, "egid>%s"},
1080         {Opt_fowner_gt, "fowner>%s"},
1081         {Opt_fgroup_gt, "fgroup>%s"},
1082         {Opt_uid_lt, "uid<%s"},
1083         {Opt_euid_lt, "euid<%s"},
1084         {Opt_gid_lt, "gid<%s"},
1085         {Opt_egid_lt, "egid<%s"},
1086         {Opt_fowner_lt, "fowner<%s"},
1087         {Opt_fgroup_lt, "fgroup<%s"},
1088         {Opt_digest_type, "digest_type=%s"},
1089         {Opt_appraise_type, "appraise_type=%s"},
1090         {Opt_appraise_flag, "appraise_flag=%s"},
1091         {Opt_appraise_algos, "appraise_algos=%s"},
1092         {Opt_permit_directio, "permit_directio"},
1093         {Opt_pcr, "pcr=%s"},
1094         {Opt_template, "template=%s"},
1095         {Opt_keyrings, "keyrings=%s"},
1096         {Opt_label, "label=%s"},
1097         {Opt_err, NULL}
1098 };
1099
1100 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1101                              substring_t *args, int lsm_rule, int audit_type)
1102 {
1103         int result;
1104
1105         if (entry->lsm[lsm_rule].rule)
1106                 return -EINVAL;
1107
1108         entry->lsm[lsm_rule].args_p = match_strdup(args);
1109         if (!entry->lsm[lsm_rule].args_p)
1110                 return -ENOMEM;
1111
1112         entry->lsm[lsm_rule].type = audit_type;
1113         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1114                                       entry->lsm[lsm_rule].args_p,
1115                                       &entry->lsm[lsm_rule].rule);
1116         if (!entry->lsm[lsm_rule].rule) {
1117                 pr_warn("rule for LSM \'%s\' is undefined\n",
1118                         entry->lsm[lsm_rule].args_p);
1119
1120                 if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1121                         kfree(entry->lsm[lsm_rule].args_p);
1122                         entry->lsm[lsm_rule].args_p = NULL;
1123                         result = -EINVAL;
1124                 } else
1125                         result = 0;
1126         }
1127
1128         return result;
1129 }
1130
1131 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1132                               enum policy_opt rule_operator)
1133 {
1134         if (!ab)
1135                 return;
1136
1137         switch (rule_operator) {
1138         case Opt_uid_gt:
1139         case Opt_euid_gt:
1140         case Opt_gid_gt:
1141         case Opt_egid_gt:
1142         case Opt_fowner_gt:
1143         case Opt_fgroup_gt:
1144                 audit_log_format(ab, "%s>", key);
1145                 break;
1146         case Opt_uid_lt:
1147         case Opt_euid_lt:
1148         case Opt_gid_lt:
1149         case Opt_egid_lt:
1150         case Opt_fowner_lt:
1151         case Opt_fgroup_lt:
1152                 audit_log_format(ab, "%s<", key);
1153                 break;
1154         default:
1155                 audit_log_format(ab, "%s=", key);
1156         }
1157         audit_log_format(ab, "%s ", value);
1158 }
1159 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1160 {
1161         ima_log_string_op(ab, key, value, Opt_err);
1162 }
1163
1164 /*
1165  * Validating the appended signature included in the measurement list requires
1166  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1167  * field). Therefore, notify the user if they have the 'modsig' field but not
1168  * the 'd-modsig' field in the template.
1169  */
1170 static void check_template_modsig(const struct ima_template_desc *template)
1171 {
1172 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1173         bool has_modsig, has_dmodsig;
1174         static bool checked;
1175         int i;
1176
1177         /* We only need to notify the user once. */
1178         if (checked)
1179                 return;
1180
1181         has_modsig = has_dmodsig = false;
1182         for (i = 0; i < template->num_fields; i++) {
1183                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1184                         has_modsig = true;
1185                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1186                         has_dmodsig = true;
1187         }
1188
1189         if (has_modsig && !has_dmodsig)
1190                 pr_notice(MSG);
1191
1192         checked = true;
1193 #undef MSG
1194 }
1195
1196 /*
1197  * Warn if the template does not contain the given field.
1198  */
1199 static void check_template_field(const struct ima_template_desc *template,
1200                                  const char *field, const char *msg)
1201 {
1202         int i;
1203
1204         for (i = 0; i < template->num_fields; i++)
1205                 if (!strcmp(template->fields[i]->field_id, field))
1206                         return;
1207
1208         pr_notice_once("%s", msg);
1209 }
1210
1211 static bool ima_validate_rule(struct ima_rule_entry *entry)
1212 {
1213         /* Ensure that the action is set and is compatible with the flags */
1214         if (entry->action == UNKNOWN)
1215                 return false;
1216
1217         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1218                 return false;
1219
1220         if (entry->action != APPRAISE &&
1221             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1222                             IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1223                 return false;
1224
1225         /*
1226          * The IMA_FUNC bit must be set if and only if there's a valid hook
1227          * function specified, and vice versa. Enforcing this property allows
1228          * for the NONE case below to validate a rule without an explicit hook
1229          * function.
1230          */
1231         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1232             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1233                 return false;
1234
1235         /*
1236          * Ensure that the hook function is compatible with the other
1237          * components of the rule
1238          */
1239         switch (entry->func) {
1240         case NONE:
1241         case FILE_CHECK:
1242         case MMAP_CHECK:
1243         case BPRM_CHECK:
1244         case CREDS_CHECK:
1245         case POST_SETATTR:
1246         case FIRMWARE_CHECK:
1247         case POLICY_CHECK:
1248                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1249                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1250                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1251                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1252                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1253                                      IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1254                                      IMA_VERITY_REQUIRED))
1255                         return false;
1256
1257                 break;
1258         case MODULE_CHECK:
1259         case KEXEC_KERNEL_CHECK:
1260         case KEXEC_INITRAMFS_CHECK:
1261                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1262                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1263                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1264                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1265                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1266                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1267                                      IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1268                         return false;
1269
1270                 break;
1271         case KEXEC_CMDLINE:
1272                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1273                         return false;
1274
1275                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1276                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1277                                      IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1278                                      IMA_FGROUP))
1279                         return false;
1280
1281                 break;
1282         case KEY_CHECK:
1283                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1284                         return false;
1285
1286                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1287                                      IMA_KEYRINGS))
1288                         return false;
1289
1290                 if (ima_rule_contains_lsm_cond(entry))
1291                         return false;
1292
1293                 break;
1294         case CRITICAL_DATA:
1295                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1296                         return false;
1297
1298                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1299                                      IMA_LABEL))
1300                         return false;
1301
1302                 if (ima_rule_contains_lsm_cond(entry))
1303                         return false;
1304
1305                 break;
1306         case SETXATTR_CHECK:
1307                 /* any action other than APPRAISE is unsupported */
1308                 if (entry->action != APPRAISE)
1309                         return false;
1310
1311                 /* SETXATTR_CHECK requires an appraise_algos parameter */
1312                 if (!(entry->flags & IMA_VALIDATE_ALGOS))
1313                         return false;
1314
1315                 /*
1316                  * full policies are not supported, they would have too
1317                  * much of a performance impact
1318                  */
1319                 if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1320                         return false;
1321
1322                 break;
1323         default:
1324                 return false;
1325         }
1326
1327         /* Ensure that combinations of flags are compatible with each other */
1328         if (entry->flags & IMA_CHECK_BLACKLIST &&
1329             !(entry->flags & IMA_MODSIG_ALLOWED))
1330                 return false;
1331
1332         /*
1333          * Unlike for regular IMA 'appraise' policy rules where security.ima
1334          * xattr may contain either a file hash or signature, the security.ima
1335          * xattr for fsverity must contain a file signature (sigv3).  Ensure
1336          * that 'appraise' rules for fsverity require file signatures by
1337          * checking the IMA_DIGSIG_REQUIRED flag is set.
1338          */
1339         if (entry->action == APPRAISE &&
1340             (entry->flags & IMA_VERITY_REQUIRED) &&
1341             !(entry->flags & IMA_DIGSIG_REQUIRED))
1342                 return false;
1343
1344         return true;
1345 }
1346
1347 static unsigned int ima_parse_appraise_algos(char *arg)
1348 {
1349         unsigned int res = 0;
1350         int idx;
1351         char *token;
1352
1353         while ((token = strsep(&arg, ",")) != NULL) {
1354                 idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1355
1356                 if (idx < 0) {
1357                         pr_err("unknown hash algorithm \"%s\"",
1358                                token);
1359                         return 0;
1360                 }
1361
1362                 if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1363                         pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1364                                token);
1365                         return 0;
1366                 }
1367
1368                 /* Add the hash algorithm to the 'allowed' bitfield */
1369                 res |= (1U << idx);
1370         }
1371
1372         return res;
1373 }
1374
1375 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1376 {
1377         struct audit_buffer *ab;
1378         char *from;
1379         char *p;
1380         bool eid_token; /* either euid or egid */
1381         struct ima_template_desc *template_desc;
1382         int result = 0;
1383
1384         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1385                                        AUDIT_INTEGRITY_POLICY_RULE);
1386
1387         entry->uid = INVALID_UID;
1388         entry->gid = INVALID_GID;
1389         entry->fowner = INVALID_UID;
1390         entry->fgroup = INVALID_GID;
1391         entry->uid_op = &uid_eq;
1392         entry->gid_op = &gid_eq;
1393         entry->fowner_op = &uid_eq;
1394         entry->fgroup_op = &gid_eq;
1395         entry->action = UNKNOWN;
1396         while ((p = strsep(&rule, " \t")) != NULL) {
1397                 substring_t args[MAX_OPT_ARGS];
1398                 int token;
1399                 unsigned long lnum;
1400
1401                 if (result < 0)
1402                         break;
1403                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1404                         continue;
1405                 token = match_token(p, policy_tokens, args);
1406                 switch (token) {
1407                 case Opt_measure:
1408                         ima_log_string(ab, "action", "measure");
1409
1410                         if (entry->action != UNKNOWN)
1411                                 result = -EINVAL;
1412
1413                         entry->action = MEASURE;
1414                         break;
1415                 case Opt_dont_measure:
1416                         ima_log_string(ab, "action", "dont_measure");
1417
1418                         if (entry->action != UNKNOWN)
1419                                 result = -EINVAL;
1420
1421                         entry->action = DONT_MEASURE;
1422                         break;
1423                 case Opt_appraise:
1424                         ima_log_string(ab, "action", "appraise");
1425
1426                         if (entry->action != UNKNOWN)
1427                                 result = -EINVAL;
1428
1429                         entry->action = APPRAISE;
1430                         break;
1431                 case Opt_dont_appraise:
1432                         ima_log_string(ab, "action", "dont_appraise");
1433
1434                         if (entry->action != UNKNOWN)
1435                                 result = -EINVAL;
1436
1437                         entry->action = DONT_APPRAISE;
1438                         break;
1439                 case Opt_audit:
1440                         ima_log_string(ab, "action", "audit");
1441
1442                         if (entry->action != UNKNOWN)
1443                                 result = -EINVAL;
1444
1445                         entry->action = AUDIT;
1446                         break;
1447                 case Opt_hash:
1448                         ima_log_string(ab, "action", "hash");
1449
1450                         if (entry->action != UNKNOWN)
1451                                 result = -EINVAL;
1452
1453                         entry->action = HASH;
1454                         break;
1455                 case Opt_dont_hash:
1456                         ima_log_string(ab, "action", "dont_hash");
1457
1458                         if (entry->action != UNKNOWN)
1459                                 result = -EINVAL;
1460
1461                         entry->action = DONT_HASH;
1462                         break;
1463                 case Opt_func:
1464                         ima_log_string(ab, "func", args[0].from);
1465
1466                         if (entry->func)
1467                                 result = -EINVAL;
1468
1469                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1470                                 entry->func = FILE_CHECK;
1471                         /* PATH_CHECK is for backwards compat */
1472                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1473                                 entry->func = FILE_CHECK;
1474                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1475                                 entry->func = MODULE_CHECK;
1476                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1477                                 entry->func = FIRMWARE_CHECK;
1478                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1479                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1480                                 entry->func = MMAP_CHECK;
1481                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1482                                 entry->func = BPRM_CHECK;
1483                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1484                                 entry->func = CREDS_CHECK;
1485                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1486                                  0)
1487                                 entry->func = KEXEC_KERNEL_CHECK;
1488                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1489                                  == 0)
1490                                 entry->func = KEXEC_INITRAMFS_CHECK;
1491                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1492                                 entry->func = POLICY_CHECK;
1493                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1494                                 entry->func = KEXEC_CMDLINE;
1495                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1496                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1497                                 entry->func = KEY_CHECK;
1498                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1499                                 entry->func = CRITICAL_DATA;
1500                         else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1501                                 entry->func = SETXATTR_CHECK;
1502                         else
1503                                 result = -EINVAL;
1504                         if (!result)
1505                                 entry->flags |= IMA_FUNC;
1506                         break;
1507                 case Opt_mask:
1508                         ima_log_string(ab, "mask", args[0].from);
1509
1510                         if (entry->mask)
1511                                 result = -EINVAL;
1512
1513                         from = args[0].from;
1514                         if (*from == '^')
1515                                 from++;
1516
1517                         if ((strcmp(from, "MAY_EXEC")) == 0)
1518                                 entry->mask = MAY_EXEC;
1519                         else if (strcmp(from, "MAY_WRITE") == 0)
1520                                 entry->mask = MAY_WRITE;
1521                         else if (strcmp(from, "MAY_READ") == 0)
1522                                 entry->mask = MAY_READ;
1523                         else if (strcmp(from, "MAY_APPEND") == 0)
1524                                 entry->mask = MAY_APPEND;
1525                         else
1526                                 result = -EINVAL;
1527                         if (!result)
1528                                 entry->flags |= (*args[0].from == '^')
1529                                      ? IMA_INMASK : IMA_MASK;
1530                         break;
1531                 case Opt_fsmagic:
1532                         ima_log_string(ab, "fsmagic", args[0].from);
1533
1534                         if (entry->fsmagic) {
1535                                 result = -EINVAL;
1536                                 break;
1537                         }
1538
1539                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1540                         if (!result)
1541                                 entry->flags |= IMA_FSMAGIC;
1542                         break;
1543                 case Opt_fsname:
1544                         ima_log_string(ab, "fsname", args[0].from);
1545
1546                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1547                         if (!entry->fsname) {
1548                                 result = -ENOMEM;
1549                                 break;
1550                         }
1551                         result = 0;
1552                         entry->flags |= IMA_FSNAME;
1553                         break;
1554                 case Opt_keyrings:
1555                         ima_log_string(ab, "keyrings", args[0].from);
1556
1557                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1558                             entry->keyrings) {
1559                                 result = -EINVAL;
1560                                 break;
1561                         }
1562
1563                         entry->keyrings = ima_alloc_rule_opt_list(args);
1564                         if (IS_ERR(entry->keyrings)) {
1565                                 result = PTR_ERR(entry->keyrings);
1566                                 entry->keyrings = NULL;
1567                                 break;
1568                         }
1569
1570                         entry->flags |= IMA_KEYRINGS;
1571                         break;
1572                 case Opt_label:
1573                         ima_log_string(ab, "label", args[0].from);
1574
1575                         if (entry->label) {
1576                                 result = -EINVAL;
1577                                 break;
1578                         }
1579
1580                         entry->label = ima_alloc_rule_opt_list(args);
1581                         if (IS_ERR(entry->label)) {
1582                                 result = PTR_ERR(entry->label);
1583                                 entry->label = NULL;
1584                                 break;
1585                         }
1586
1587                         entry->flags |= IMA_LABEL;
1588                         break;
1589                 case Opt_fsuuid:
1590                         ima_log_string(ab, "fsuuid", args[0].from);
1591
1592                         if (!uuid_is_null(&entry->fsuuid)) {
1593                                 result = -EINVAL;
1594                                 break;
1595                         }
1596
1597                         result = uuid_parse(args[0].from, &entry->fsuuid);
1598                         if (!result)
1599                                 entry->flags |= IMA_FSUUID;
1600                         break;
1601                 case Opt_uid_gt:
1602                 case Opt_euid_gt:
1603                         entry->uid_op = &uid_gt;
1604                         fallthrough;
1605                 case Opt_uid_lt:
1606                 case Opt_euid_lt:
1607                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1608                                 entry->uid_op = &uid_lt;
1609                         fallthrough;
1610                 case Opt_uid_eq:
1611                 case Opt_euid_eq:
1612                         eid_token = (token == Opt_euid_eq) ||
1613                                     (token == Opt_euid_gt) ||
1614                                     (token == Opt_euid_lt);
1615
1616                         ima_log_string_op(ab, eid_token ? "euid" : "uid",
1617                                           args[0].from, token);
1618
1619                         if (uid_valid(entry->uid)) {
1620                                 result = -EINVAL;
1621                                 break;
1622                         }
1623
1624                         result = kstrtoul(args[0].from, 10, &lnum);
1625                         if (!result) {
1626                                 entry->uid = make_kuid(current_user_ns(),
1627                                                        (uid_t) lnum);
1628                                 if (!uid_valid(entry->uid) ||
1629                                     (uid_t)lnum != lnum)
1630                                         result = -EINVAL;
1631                                 else
1632                                         entry->flags |= eid_token
1633                                             ? IMA_EUID : IMA_UID;
1634                         }
1635                         break;
1636                 case Opt_gid_gt:
1637                 case Opt_egid_gt:
1638                         entry->gid_op = &gid_gt;
1639                         fallthrough;
1640                 case Opt_gid_lt:
1641                 case Opt_egid_lt:
1642                         if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1643                                 entry->gid_op = &gid_lt;
1644                         fallthrough;
1645                 case Opt_gid_eq:
1646                 case Opt_egid_eq:
1647                         eid_token = (token == Opt_egid_eq) ||
1648                                     (token == Opt_egid_gt) ||
1649                                     (token == Opt_egid_lt);
1650
1651                         ima_log_string_op(ab, eid_token ? "egid" : "gid",
1652                                           args[0].from, token);
1653
1654                         if (gid_valid(entry->gid)) {
1655                                 result = -EINVAL;
1656                                 break;
1657                         }
1658
1659                         result = kstrtoul(args[0].from, 10, &lnum);
1660                         if (!result) {
1661                                 entry->gid = make_kgid(current_user_ns(),
1662                                                        (gid_t)lnum);
1663                                 if (!gid_valid(entry->gid) ||
1664                                     (((gid_t)lnum) != lnum))
1665                                         result = -EINVAL;
1666                                 else
1667                                         entry->flags |= eid_token
1668                                             ? IMA_EGID : IMA_GID;
1669                         }
1670                         break;
1671                 case Opt_fowner_gt:
1672                         entry->fowner_op = &uid_gt;
1673                         fallthrough;
1674                 case Opt_fowner_lt:
1675                         if (token == Opt_fowner_lt)
1676                                 entry->fowner_op = &uid_lt;
1677                         fallthrough;
1678                 case Opt_fowner_eq:
1679                         ima_log_string_op(ab, "fowner", args[0].from, token);
1680
1681                         if (uid_valid(entry->fowner)) {
1682                                 result = -EINVAL;
1683                                 break;
1684                         }
1685
1686                         result = kstrtoul(args[0].from, 10, &lnum);
1687                         if (!result) {
1688                                 entry->fowner = make_kuid(current_user_ns(),
1689                                                           (uid_t)lnum);
1690                                 if (!uid_valid(entry->fowner) ||
1691                                     (((uid_t)lnum) != lnum))
1692                                         result = -EINVAL;
1693                                 else
1694                                         entry->flags |= IMA_FOWNER;
1695                         }
1696                         break;
1697                 case Opt_fgroup_gt:
1698                         entry->fgroup_op = &gid_gt;
1699                         fallthrough;
1700                 case Opt_fgroup_lt:
1701                         if (token == Opt_fgroup_lt)
1702                                 entry->fgroup_op = &gid_lt;
1703                         fallthrough;
1704                 case Opt_fgroup_eq:
1705                         ima_log_string_op(ab, "fgroup", args[0].from, token);
1706
1707                         if (gid_valid(entry->fgroup)) {
1708                                 result = -EINVAL;
1709                                 break;
1710                         }
1711
1712                         result = kstrtoul(args[0].from, 10, &lnum);
1713                         if (!result) {
1714                                 entry->fgroup = make_kgid(current_user_ns(),
1715                                                           (gid_t)lnum);
1716                                 if (!gid_valid(entry->fgroup) ||
1717                                     (((gid_t)lnum) != lnum))
1718                                         result = -EINVAL;
1719                                 else
1720                                         entry->flags |= IMA_FGROUP;
1721                         }
1722                         break;
1723                 case Opt_obj_user:
1724                         ima_log_string(ab, "obj_user", args[0].from);
1725                         result = ima_lsm_rule_init(entry, args,
1726                                                    LSM_OBJ_USER,
1727                                                    AUDIT_OBJ_USER);
1728                         break;
1729                 case Opt_obj_role:
1730                         ima_log_string(ab, "obj_role", args[0].from);
1731                         result = ima_lsm_rule_init(entry, args,
1732                                                    LSM_OBJ_ROLE,
1733                                                    AUDIT_OBJ_ROLE);
1734                         break;
1735                 case Opt_obj_type:
1736                         ima_log_string(ab, "obj_type", args[0].from);
1737                         result = ima_lsm_rule_init(entry, args,
1738                                                    LSM_OBJ_TYPE,
1739                                                    AUDIT_OBJ_TYPE);
1740                         break;
1741                 case Opt_subj_user:
1742                         ima_log_string(ab, "subj_user", args[0].from);
1743                         result = ima_lsm_rule_init(entry, args,
1744                                                    LSM_SUBJ_USER,
1745                                                    AUDIT_SUBJ_USER);
1746                         break;
1747                 case Opt_subj_role:
1748                         ima_log_string(ab, "subj_role", args[0].from);
1749                         result = ima_lsm_rule_init(entry, args,
1750                                                    LSM_SUBJ_ROLE,
1751                                                    AUDIT_SUBJ_ROLE);
1752                         break;
1753                 case Opt_subj_type:
1754                         ima_log_string(ab, "subj_type", args[0].from);
1755                         result = ima_lsm_rule_init(entry, args,
1756                                                    LSM_SUBJ_TYPE,
1757                                                    AUDIT_SUBJ_TYPE);
1758                         break;
1759                 case Opt_digest_type:
1760                         ima_log_string(ab, "digest_type", args[0].from);
1761                         if (entry->flags & IMA_DIGSIG_REQUIRED)
1762                                 result = -EINVAL;
1763                         else if ((strcmp(args[0].from, "verity")) == 0)
1764                                 entry->flags |= IMA_VERITY_REQUIRED;
1765                         else
1766                                 result = -EINVAL;
1767                         break;
1768                 case Opt_appraise_type:
1769                         ima_log_string(ab, "appraise_type", args[0].from);
1770
1771                         if ((strcmp(args[0].from, "imasig")) == 0) {
1772                                 if (entry->flags & IMA_VERITY_REQUIRED)
1773                                         result = -EINVAL;
1774                                 else
1775                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1776                         } else if (strcmp(args[0].from, "sigv3") == 0) {
1777                                 /* Only fsverity supports sigv3 for now */
1778                                 if (entry->flags & IMA_VERITY_REQUIRED)
1779                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1780                                 else
1781                                         result = -EINVAL;
1782                         } else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1783                                  strcmp(args[0].from, "imasig|modsig") == 0) {
1784                                 if (entry->flags & IMA_VERITY_REQUIRED)
1785                                         result = -EINVAL;
1786                                 else
1787                                         entry->flags |= IMA_DIGSIG_REQUIRED |
1788                                                 IMA_MODSIG_ALLOWED;
1789                         } else {
1790                                 result = -EINVAL;
1791                         }
1792                         break;
1793                 case Opt_appraise_flag:
1794                         ima_log_string(ab, "appraise_flag", args[0].from);
1795                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1796                             strstr(args[0].from, "blacklist"))
1797                                 entry->flags |= IMA_CHECK_BLACKLIST;
1798                         else
1799                                 result = -EINVAL;
1800                         break;
1801                 case Opt_appraise_algos:
1802                         ima_log_string(ab, "appraise_algos", args[0].from);
1803
1804                         if (entry->allowed_algos) {
1805                                 result = -EINVAL;
1806                                 break;
1807                         }
1808
1809                         entry->allowed_algos =
1810                                 ima_parse_appraise_algos(args[0].from);
1811                         /* invalid or empty list of algorithms */
1812                         if (!entry->allowed_algos) {
1813                                 result = -EINVAL;
1814                                 break;
1815                         }
1816
1817                         entry->flags |= IMA_VALIDATE_ALGOS;
1818
1819                         break;
1820                 case Opt_permit_directio:
1821                         entry->flags |= IMA_PERMIT_DIRECTIO;
1822                         break;
1823                 case Opt_pcr:
1824                         ima_log_string(ab, "pcr", args[0].from);
1825
1826                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1827                         if (result || INVALID_PCR(entry->pcr))
1828                                 result = -EINVAL;
1829                         else
1830                                 entry->flags |= IMA_PCR;
1831
1832                         break;
1833                 case Opt_template:
1834                         ima_log_string(ab, "template", args[0].from);
1835                         if (entry->action != MEASURE) {
1836                                 result = -EINVAL;
1837                                 break;
1838                         }
1839                         template_desc = lookup_template_desc(args[0].from);
1840                         if (!template_desc || entry->template) {
1841                                 result = -EINVAL;
1842                                 break;
1843                         }
1844
1845                         /*
1846                          * template_desc_init_fields() does nothing if
1847                          * the template is already initialised, so
1848                          * it's safe to do this unconditionally
1849                          */
1850                         template_desc_init_fields(template_desc->fmt,
1851                                                  &(template_desc->fields),
1852                                                  &(template_desc->num_fields));
1853                         entry->template = template_desc;
1854                         break;
1855                 case Opt_err:
1856                         ima_log_string(ab, "UNKNOWN", p);
1857                         result = -EINVAL;
1858                         break;
1859                 }
1860         }
1861         if (!result && !ima_validate_rule(entry))
1862                 result = -EINVAL;
1863         else if (entry->action == APPRAISE)
1864                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1865
1866         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1867                 template_desc = entry->template ? entry->template :
1868                                                   ima_template_desc_current();
1869                 check_template_modsig(template_desc);
1870         }
1871
1872         /* d-ngv2 template field recommended for unsigned fs-verity digests */
1873         if (!result && entry->action == MEASURE &&
1874             entry->flags & IMA_VERITY_REQUIRED) {
1875                 template_desc = entry->template ? entry->template :
1876                                                   ima_template_desc_current();
1877                 check_template_field(template_desc, "d-ngv2",
1878                                      "verity rules should include d-ngv2");
1879         }
1880
1881         audit_log_format(ab, "res=%d", !result);
1882         audit_log_end(ab);
1883         return result;
1884 }
1885
1886 /**
1887  * ima_parse_add_rule - add a rule to ima_policy_rules
1888  * @rule - ima measurement policy rule
1889  *
1890  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1891  * Returns the length of the rule parsed, an error code on failure
1892  */
1893 ssize_t ima_parse_add_rule(char *rule)
1894 {
1895         static const char op[] = "update_policy";
1896         char *p;
1897         struct ima_rule_entry *entry;
1898         ssize_t result, len;
1899         int audit_info = 0;
1900
1901         p = strsep(&rule, "\n");
1902         len = strlen(p) + 1;
1903         p += strspn(p, " \t");
1904
1905         if (*p == '#' || *p == '\0')
1906                 return len;
1907
1908         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1909         if (!entry) {
1910                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1911                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1912                 return -ENOMEM;
1913         }
1914
1915         INIT_LIST_HEAD(&entry->list);
1916
1917         result = ima_parse_rule(p, entry);
1918         if (result) {
1919                 ima_free_rule(entry);
1920                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1921                                     NULL, op, "invalid-policy", result,
1922                                     audit_info);
1923                 return result;
1924         }
1925
1926         list_add_tail(&entry->list, &ima_temp_rules);
1927
1928         return len;
1929 }
1930
1931 /**
1932  * ima_delete_rules() called to cleanup invalid in-flight policy.
1933  * We don't need locking as we operate on the temp list, which is
1934  * different from the active one.  There is also only one user of
1935  * ima_delete_rules() at a time.
1936  */
1937 void ima_delete_rules(void)
1938 {
1939         struct ima_rule_entry *entry, *tmp;
1940
1941         temp_ima_appraise = 0;
1942         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1943                 list_del(&entry->list);
1944                 ima_free_rule(entry);
1945         }
1946 }
1947
1948 #define __ima_hook_stringify(func, str) (#func),
1949
1950 const char *const func_tokens[] = {
1951         __ima_hooks(__ima_hook_stringify)
1952 };
1953
1954 #ifdef  CONFIG_IMA_READ_POLICY
1955 enum {
1956         mask_exec = 0, mask_write, mask_read, mask_append
1957 };
1958
1959 static const char *const mask_tokens[] = {
1960         "^MAY_EXEC",
1961         "^MAY_WRITE",
1962         "^MAY_READ",
1963         "^MAY_APPEND"
1964 };
1965
1966 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1967 {
1968         loff_t l = *pos;
1969         struct ima_rule_entry *entry;
1970         struct list_head *ima_rules_tmp;
1971
1972         rcu_read_lock();
1973         ima_rules_tmp = rcu_dereference(ima_rules);
1974         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
1975                 if (!l--) {
1976                         rcu_read_unlock();
1977                         return entry;
1978                 }
1979         }
1980         rcu_read_unlock();
1981         return NULL;
1982 }
1983
1984 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1985 {
1986         struct ima_rule_entry *entry = v;
1987
1988         rcu_read_lock();
1989         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1990         rcu_read_unlock();
1991         (*pos)++;
1992
1993         return (&entry->list == &ima_default_rules ||
1994                 &entry->list == &ima_policy_rules) ? NULL : entry;
1995 }
1996
1997 void ima_policy_stop(struct seq_file *m, void *v)
1998 {
1999 }
2000
2001 #define pt(token)       policy_tokens[token].pattern
2002 #define mt(token)       mask_tokens[token]
2003
2004 /*
2005  * policy_func_show - display the ima_hooks policy rule
2006  */
2007 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
2008 {
2009         if (func > 0 && func < MAX_CHECK)
2010                 seq_printf(m, "func=%s ", func_tokens[func]);
2011         else
2012                 seq_printf(m, "func=%d ", func);
2013 }
2014
2015 static void ima_show_rule_opt_list(struct seq_file *m,
2016                                    const struct ima_rule_opt_list *opt_list)
2017 {
2018         size_t i;
2019
2020         for (i = 0; i < opt_list->count; i++)
2021                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
2022 }
2023
2024 static void ima_policy_show_appraise_algos(struct seq_file *m,
2025                                            unsigned int allowed_hashes)
2026 {
2027         int idx, list_size = 0;
2028
2029         for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
2030                 if (!(allowed_hashes & (1U << idx)))
2031                         continue;
2032
2033                 /* only add commas if the list contains multiple entries */
2034                 if (list_size++)
2035                         seq_puts(m, ",");
2036
2037                 seq_puts(m, hash_algo_name[idx]);
2038         }
2039 }
2040
2041 int ima_policy_show(struct seq_file *m, void *v)
2042 {
2043         struct ima_rule_entry *entry = v;
2044         int i;
2045         char tbuf[64] = {0,};
2046         int offset = 0;
2047
2048         rcu_read_lock();
2049
2050         /* Do not print rules with inactive LSM labels */
2051         for (i = 0; i < MAX_LSM_RULES; i++) {
2052                 if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
2053                         rcu_read_unlock();
2054                         return 0;
2055                 }
2056         }
2057
2058         if (entry->action & MEASURE)
2059                 seq_puts(m, pt(Opt_measure));
2060         if (entry->action & DONT_MEASURE)
2061                 seq_puts(m, pt(Opt_dont_measure));
2062         if (entry->action & APPRAISE)
2063                 seq_puts(m, pt(Opt_appraise));
2064         if (entry->action & DONT_APPRAISE)
2065                 seq_puts(m, pt(Opt_dont_appraise));
2066         if (entry->action & AUDIT)
2067                 seq_puts(m, pt(Opt_audit));
2068         if (entry->action & HASH)
2069                 seq_puts(m, pt(Opt_hash));
2070         if (entry->action & DONT_HASH)
2071                 seq_puts(m, pt(Opt_dont_hash));
2072
2073         seq_puts(m, " ");
2074
2075         if (entry->flags & IMA_FUNC)
2076                 policy_func_show(m, entry->func);
2077
2078         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
2079                 if (entry->flags & IMA_MASK)
2080                         offset = 1;
2081                 if (entry->mask & MAY_EXEC)
2082                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2083                 if (entry->mask & MAY_WRITE)
2084                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2085                 if (entry->mask & MAY_READ)
2086                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2087                 if (entry->mask & MAY_APPEND)
2088                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2089                 seq_puts(m, " ");
2090         }
2091
2092         if (entry->flags & IMA_FSMAGIC) {
2093                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2094                 seq_printf(m, pt(Opt_fsmagic), tbuf);
2095                 seq_puts(m, " ");
2096         }
2097
2098         if (entry->flags & IMA_FSNAME) {
2099                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2100                 seq_printf(m, pt(Opt_fsname), tbuf);
2101                 seq_puts(m, " ");
2102         }
2103
2104         if (entry->flags & IMA_KEYRINGS) {
2105                 seq_puts(m, "keyrings=");
2106                 ima_show_rule_opt_list(m, entry->keyrings);
2107                 seq_puts(m, " ");
2108         }
2109
2110         if (entry->flags & IMA_LABEL) {
2111                 seq_puts(m, "label=");
2112                 ima_show_rule_opt_list(m, entry->label);
2113                 seq_puts(m, " ");
2114         }
2115
2116         if (entry->flags & IMA_PCR) {
2117                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2118                 seq_printf(m, pt(Opt_pcr), tbuf);
2119                 seq_puts(m, " ");
2120         }
2121
2122         if (entry->flags & IMA_FSUUID) {
2123                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2124                 seq_puts(m, " ");
2125         }
2126
2127         if (entry->flags & IMA_UID) {
2128                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2129                 if (entry->uid_op == &uid_gt)
2130                         seq_printf(m, pt(Opt_uid_gt), tbuf);
2131                 else if (entry->uid_op == &uid_lt)
2132                         seq_printf(m, pt(Opt_uid_lt), tbuf);
2133                 else
2134                         seq_printf(m, pt(Opt_uid_eq), tbuf);
2135                 seq_puts(m, " ");
2136         }
2137
2138         if (entry->flags & IMA_EUID) {
2139                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2140                 if (entry->uid_op == &uid_gt)
2141                         seq_printf(m, pt(Opt_euid_gt), tbuf);
2142                 else if (entry->uid_op == &uid_lt)
2143                         seq_printf(m, pt(Opt_euid_lt), tbuf);
2144                 else
2145                         seq_printf(m, pt(Opt_euid_eq), tbuf);
2146                 seq_puts(m, " ");
2147         }
2148
2149         if (entry->flags & IMA_GID) {
2150                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2151                 if (entry->gid_op == &gid_gt)
2152                         seq_printf(m, pt(Opt_gid_gt), tbuf);
2153                 else if (entry->gid_op == &gid_lt)
2154                         seq_printf(m, pt(Opt_gid_lt), tbuf);
2155                 else
2156                         seq_printf(m, pt(Opt_gid_eq), tbuf);
2157                 seq_puts(m, " ");
2158         }
2159
2160         if (entry->flags & IMA_EGID) {
2161                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2162                 if (entry->gid_op == &gid_gt)
2163                         seq_printf(m, pt(Opt_egid_gt), tbuf);
2164                 else if (entry->gid_op == &gid_lt)
2165                         seq_printf(m, pt(Opt_egid_lt), tbuf);
2166                 else
2167                         seq_printf(m, pt(Opt_egid_eq), tbuf);
2168                 seq_puts(m, " ");
2169         }
2170
2171         if (entry->flags & IMA_FOWNER) {
2172                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2173                 if (entry->fowner_op == &uid_gt)
2174                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
2175                 else if (entry->fowner_op == &uid_lt)
2176                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
2177                 else
2178                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
2179                 seq_puts(m, " ");
2180         }
2181
2182         if (entry->flags & IMA_FGROUP) {
2183                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2184                 if (entry->fgroup_op == &gid_gt)
2185                         seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2186                 else if (entry->fgroup_op == &gid_lt)
2187                         seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2188                 else
2189                         seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2190                 seq_puts(m, " ");
2191         }
2192
2193         if (entry->flags & IMA_VALIDATE_ALGOS) {
2194                 seq_puts(m, "appraise_algos=");
2195                 ima_policy_show_appraise_algos(m, entry->allowed_algos);
2196                 seq_puts(m, " ");
2197         }
2198
2199         for (i = 0; i < MAX_LSM_RULES; i++) {
2200                 if (entry->lsm[i].rule) {
2201                         switch (i) {
2202                         case LSM_OBJ_USER:
2203                                 seq_printf(m, pt(Opt_obj_user),
2204                                            entry->lsm[i].args_p);
2205                                 break;
2206                         case LSM_OBJ_ROLE:
2207                                 seq_printf(m, pt(Opt_obj_role),
2208                                            entry->lsm[i].args_p);
2209                                 break;
2210                         case LSM_OBJ_TYPE:
2211                                 seq_printf(m, pt(Opt_obj_type),
2212                                            entry->lsm[i].args_p);
2213                                 break;
2214                         case LSM_SUBJ_USER:
2215                                 seq_printf(m, pt(Opt_subj_user),
2216                                            entry->lsm[i].args_p);
2217                                 break;
2218                         case LSM_SUBJ_ROLE:
2219                                 seq_printf(m, pt(Opt_subj_role),
2220                                            entry->lsm[i].args_p);
2221                                 break;
2222                         case LSM_SUBJ_TYPE:
2223                                 seq_printf(m, pt(Opt_subj_type),
2224                                            entry->lsm[i].args_p);
2225                                 break;
2226                         }
2227                         seq_puts(m, " ");
2228                 }
2229         }
2230         if (entry->template)
2231                 seq_printf(m, "template=%s ", entry->template->name);
2232         if (entry->flags & IMA_DIGSIG_REQUIRED) {
2233                 if (entry->flags & IMA_VERITY_REQUIRED)
2234                         seq_puts(m, "appraise_type=sigv3 ");
2235                 else if (entry->flags & IMA_MODSIG_ALLOWED)
2236                         seq_puts(m, "appraise_type=imasig|modsig ");
2237                 else
2238                         seq_puts(m, "appraise_type=imasig ");
2239         }
2240         if (entry->flags & IMA_VERITY_REQUIRED)
2241                 seq_puts(m, "digest_type=verity ");
2242         if (entry->flags & IMA_CHECK_BLACKLIST)
2243                 seq_puts(m, "appraise_flag=check_blacklist ");
2244         if (entry->flags & IMA_PERMIT_DIRECTIO)
2245                 seq_puts(m, "permit_directio ");
2246         rcu_read_unlock();
2247         seq_puts(m, "\n");
2248         return 0;
2249 }
2250 #endif  /* CONFIG_IMA_READ_POLICY */
2251
2252 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2253 /*
2254  * ima_appraise_signature: whether IMA will appraise a given function using
2255  * an IMA digital signature. This is restricted to cases where the kernel
2256  * has a set of built-in trusted keys in order to avoid an attacker simply
2257  * loading additional keys.
2258  */
2259 bool ima_appraise_signature(enum kernel_read_file_id id)
2260 {
2261         struct ima_rule_entry *entry;
2262         bool found = false;
2263         enum ima_hooks func;
2264         struct list_head *ima_rules_tmp;
2265
2266         if (id >= READING_MAX_ID)
2267                 return false;
2268
2269         if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2270             && security_locked_down(LOCKDOWN_KEXEC))
2271                 return false;
2272
2273         func = read_idmap[id] ?: FILE_CHECK;
2274
2275         rcu_read_lock();
2276         ima_rules_tmp = rcu_dereference(ima_rules);
2277         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2278                 if (entry->action != APPRAISE)
2279                         continue;
2280
2281                 /*
2282                  * A generic entry will match, but otherwise require that it
2283                  * match the func we're looking for
2284                  */
2285                 if (entry->func && entry->func != func)
2286                         continue;
2287
2288                 /*
2289                  * We require this to be a digital signature, not a raw IMA
2290                  * hash.
2291                  */
2292                 if (entry->flags & IMA_DIGSIG_REQUIRED)
2293                         found = true;
2294
2295                 /*
2296                  * We've found a rule that matches, so break now even if it
2297                  * didn't require a digital signature - a later rule that does
2298                  * won't override it, so would be a false positive.
2299                  */
2300                 break;
2301         }
2302
2303         rcu_read_unlock();
2304         return found;
2305 }
2306 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */