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 /*
  75  * These comparators are needed nowhere outside of ima so just define them here.
  76  * This pattern should hopefully never be needed outside of ima.
  77  */
  78 static inline bool vfsuid_gt_kuid(vfsuid_t vfsuid, kuid_t kuid)
  79 {
  80         return __vfsuid_val(vfsuid) > __kuid_val(kuid);
  81 }
  82
  83 static inline bool vfsgid_gt_kgid(vfsgid_t vfsgid, kgid_t kgid)
  84 {
  85         return __vfsgid_val(vfsgid) > __kgid_val(kgid);
  86 }
  87
  88 static inline bool vfsuid_lt_kuid(vfsuid_t vfsuid, kuid_t kuid)
  89 {
  90         return __vfsuid_val(vfsuid) < __kuid_val(kuid);
  91 }
  92
  93 static inline bool vfsgid_lt_kgid(vfsgid_t vfsgid, kgid_t kgid)
  94 {
  95         return __vfsgid_val(vfsgid) < __kgid_val(kgid);
  96 }
  97
  98 struct ima_rule_entry {
  99         struct list_head list;
 100         int action;
 101         unsigned int flags;
 102         enum ima_hooks func;
 103         int mask;
 104         unsigned long fsmagic;
 105         uuid_t fsuuid;
 106         kuid_t uid;
 107         kgid_t gid;
 108         kuid_t fowner;
 109         kgid_t fgroup;
 110         bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
 111         bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
 112         bool (*fowner_op)(vfsuid_t vfsuid, kuid_t rule_uid); /* vfsuid_eq_kuid(), vfsuid_gt_kuid(), vfsuid_lt_kuid() */
 113         bool (*fgroup_op)(vfsgid_t vfsgid, kgid_t rule_gid); /* vfsgid_eq_kgid(), vfsgid_gt_kgid(), vfsgid_lt_kgid() */
 114         int pcr;
 115         unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
 116         struct {
 117                 void *rule;     /* LSM file metadata specific */
 118                 char *args_p;   /* audit value */
 119                 int type;       /* audit type */
 120         } lsm[MAX_LSM_RULES];
 121         char *fsname;
 122         struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
 123         struct ima_rule_opt_list *label; /* Measure data grouped under this label */
 124         struct ima_template_desc *template;
 125 };
 126
 127 /*
 128  * sanity check in case the kernels gains more hash algorithms that can
 129  * fit in an unsigned int
 130  */
 131 static_assert(
 132         8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
 133         "The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
 134
 135 /*
 136  * Without LSM specific knowledge, the default policy can only be
 137  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
 138  * .fowner, and .fgroup
 139  */
 140
 141 /*
 142  * The minimum rule set to allow for full TCB coverage.  Measures all files
 143  * opened or mmap for exec and everything read by root.  Dangerous because
 144  * normal users can easily run the machine out of memory simply building
 145  * and running executables.
 146  */
 147 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
 148         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 149         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 150         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 151         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 152         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 153         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 154         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 155         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 156         {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 157         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
 158          .flags = IMA_FSMAGIC},
 159         {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
 160          .flags = IMA_FSMAGIC},
 161         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 162         {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
 163 };
 164
 165 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
 166         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 167          .flags = IMA_FUNC | IMA_MASK},
 168         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 169          .flags = IMA_FUNC | IMA_MASK},
 170         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 171          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 172          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 173         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 174         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 175 };
 176
 177 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
 178         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 179          .flags = IMA_FUNC | IMA_MASK},
 180         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 181          .flags = IMA_FUNC | IMA_MASK},
 182         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 183          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 184          .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 185         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 186          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 187          .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 188         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 189         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 190         {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
 191 };
 192
 193 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
 194         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 195         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 196         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 197         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 198         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 199         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 200         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 201         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 202         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 203         {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 204         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 205         {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
 206         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 207         {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 208 #ifdef CONFIG_IMA_WRITE_POLICY
 209         {.action = APPRAISE, .func = POLICY_CHECK,
 210         .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 211 #endif
 212 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 213         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
 214          .flags = IMA_FOWNER},
 215 #else
 216         /* force signature */
 217         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
 218          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 219 #endif
 220 };
 221
 222 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 223 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
 224         {.action = APPRAISE, .func = MODULE_CHECK,
 225          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 226 #endif
 227 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
 228         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 229          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 230 #endif
 231 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
 232         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 233          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 234 #endif
 235 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
 236         {.action = APPRAISE, .func = POLICY_CHECK,
 237          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 238 #endif
 239 };
 240
 241 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 242         {.action = APPRAISE, .func = MODULE_CHECK,
 243          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 244         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 245          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 246         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 247          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 248         {.action = APPRAISE, .func = POLICY_CHECK,
 249          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 250 };
 251
 252 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
 253         {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
 254 };
 255
 256 /* An array of architecture specific rules */
 257 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 258
 259 static LIST_HEAD(ima_default_rules);
 260 static LIST_HEAD(ima_policy_rules);
 261 static LIST_HEAD(ima_temp_rules);
 262 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
 263
 264 static int ima_policy __initdata;
 265
 266 static int __init default_measure_policy_setup(char *str)
 267 {
 268         if (ima_policy)
 269                 return 1;
 270
 271         ima_policy = ORIGINAL_TCB;
 272         return 1;
 273 }
 274 __setup("ima_tcb", default_measure_policy_setup);
 275
 276 static bool ima_use_appraise_tcb __initdata;
 277 static bool ima_use_secure_boot __initdata;
 278 static bool ima_use_critical_data __initdata;
 279 static bool ima_fail_unverifiable_sigs __ro_after_init;
 280 static int __init policy_setup(char *str)
 281 {
 282         char *p;
 283
 284         while ((p = strsep(&str, " |\n")) != NULL) {
 285                 if (*p == ' ')
 286                         continue;
 287                 if ((strcmp(p, "tcb") == 0) && !ima_policy)
 288                         ima_policy = DEFAULT_TCB;
 289                 else if (strcmp(p, "appraise_tcb") == 0)
 290                         ima_use_appraise_tcb = true;
 291                 else if (strcmp(p, "secure_boot") == 0)
 292                         ima_use_secure_boot = true;
 293                 else if (strcmp(p, "critical_data") == 0)
 294                         ima_use_critical_data = true;
 295                 else if (strcmp(p, "fail_securely") == 0)
 296                         ima_fail_unverifiable_sigs = true;
 297                 else
 298                         pr_err("policy \"%s\" not found", p);
 299         }
 300
 301         return 1;
 302 }
 303 __setup("ima_policy=", policy_setup);
 304
 305 static int __init default_appraise_policy_setup(char *str)
 306 {
 307         ima_use_appraise_tcb = true;
 308         return 1;
 309 }
 310 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 311
 312 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 313 {
 314         struct ima_rule_opt_list *opt_list;
 315         size_t count = 0;
 316         char *src_copy;
 317         char *cur, *next;
 318         size_t i;
 319
 320         src_copy = match_strdup(src);
 321         if (!src_copy)
 322                 return ERR_PTR(-ENOMEM);
 323
 324         next = src_copy;
 325         while ((cur = strsep(&next, "|"))) {
 326                 /* Don't accept an empty list item */
 327                 if (!(*cur)) {
 328                         kfree(src_copy);
 329                         return ERR_PTR(-EINVAL);
 330                 }
 331                 count++;
 332         }
 333
 334         /* Don't accept an empty list */
 335         if (!count) {
 336                 kfree(src_copy);
 337                 return ERR_PTR(-EINVAL);
 338         }
 339
 340         opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
 341         if (!opt_list) {
 342                 kfree(src_copy);
 343                 return ERR_PTR(-ENOMEM);
 344         }
 345
 346         /*
 347          * strsep() has already replaced all instances of '|' with '\0',
 348          * leaving a byte sequence of NUL-terminated strings. Reference each
 349          * string with the array of items.
 350          *
 351          * IMPORTANT: Ownership of the allocated buffer is transferred from
 352          * src_copy to the first element in the items array. To free the
 353          * buffer, kfree() must only be called on the first element of the
 354          * array.
 355          */
 356         for (i = 0, cur = src_copy; i < count; i++) {
 357                 opt_list->items[i] = cur;
 358                 cur = strchr(cur, '\0') + 1;
 359         }
 360         opt_list->count = count;
 361
 362         return opt_list;
 363 }
 364
 365 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 366 {
 367         if (!opt_list)
 368                 return;
 369
 370         if (opt_list->count) {
 371                 kfree(opt_list->items[0]);
 372                 opt_list->count = 0;
 373         }
 374
 375         kfree(opt_list);
 376 }
 377
 378 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 379 {
 380         int i;
 381
 382         for (i = 0; i < MAX_LSM_RULES; i++) {
 383                 ima_filter_rule_free(entry->lsm[i].rule);
 384                 kfree(entry->lsm[i].args_p);
 385         }
 386 }
 387
 388 static void ima_free_rule(struct ima_rule_entry *entry)
 389 {
 390         if (!entry)
 391                 return;
 392
 393         /*
 394          * entry->template->fields may be allocated in ima_parse_rule() but that
 395          * reference is owned by the corresponding ima_template_desc element in
 396          * the defined_templates list and cannot be freed here
 397          */
 398         kfree(entry->fsname);
 399         ima_free_rule_opt_list(entry->keyrings);
 400         ima_lsm_free_rule(entry);
 401         kfree(entry);
 402 }
 403
 404 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 405 {
 406         struct ima_rule_entry *nentry;
 407         int i;
 408
 409         /*
 410          * Immutable elements are copied over as pointers and data; only
 411          * lsm rules can change
 412          */
 413         nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
 414         if (!nentry)
 415                 return NULL;
 416
 417         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 418
 419         for (i = 0; i < MAX_LSM_RULES; i++) {
 420                 if (!entry->lsm[i].args_p)
 421                         continue;
 422
 423                 nentry->lsm[i].type = entry->lsm[i].type;
 424                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 425
 426                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 427                                      nentry->lsm[i].args_p,
 428                                      &nentry->lsm[i].rule);
 429                 if (!nentry->lsm[i].rule)
 430                         pr_warn("rule for LSM \'%s\' is undefined\n",
 431                                 nentry->lsm[i].args_p);
 432         }
 433         return nentry;
 434 }
 435
 436 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 437 {
 438         int i;
 439         struct ima_rule_entry *nentry;
 440
 441         nentry = ima_lsm_copy_rule(entry);
 442         if (!nentry)
 443                 return -ENOMEM;
 444
 445         list_replace_rcu(&entry->list, &nentry->list);
 446         synchronize_rcu();
 447         /*
 448          * ima_lsm_copy_rule() shallow copied all references, except for the
 449          * LSM references, from entry to nentry so we only want to free the LSM
 450          * references and the entry itself. All other memory references will now
 451          * be owned by nentry.
 452          */
 453         for (i = 0; i < MAX_LSM_RULES; i++)
 454                 ima_filter_rule_free(entry->lsm[i].rule);
 455         kfree(entry);
 456
 457         return 0;
 458 }
 459
 460 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 461 {
 462         int i;
 463
 464         for (i = 0; i < MAX_LSM_RULES; i++)
 465                 if (entry->lsm[i].args_p)
 466                         return true;
 467
 468         return false;
 469 }
 470
 471 /*
 472  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 473  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 474  * the reloaded LSM policy.
 475  */
 476 static void ima_lsm_update_rules(void)
 477 {
 478         struct ima_rule_entry *entry, *e;
 479         int result;
 480
 481         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 482                 if (!ima_rule_contains_lsm_cond(entry))
 483                         continue;
 484
 485                 result = ima_lsm_update_rule(entry);
 486                 if (result) {
 487                         pr_err("lsm rule update error %d\n", result);
 488                         return;
 489                 }
 490         }
 491 }
 492
 493 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 494                           void *lsm_data)
 495 {
 496         if (event != LSM_POLICY_CHANGE)
 497                 return NOTIFY_DONE;
 498
 499         ima_lsm_update_rules();
 500         return NOTIFY_OK;
 501 }
 502
 503 /**
 504  * ima_match_rule_data - determine whether func_data matches the policy rule
 505  * @rule: a pointer to a rule
 506  * @func_data: data to match against the measure rule data
 507  * @cred: a pointer to a credentials structure for user validation
 508  *
 509  * Returns true if func_data matches one in the rule, false otherwise.
 510  */
 511 static bool ima_match_rule_data(struct ima_rule_entry *rule,
 512                                 const char *func_data,
 513                                 const struct cred *cred)
 514 {
 515         const struct ima_rule_opt_list *opt_list = NULL;
 516         bool matched = false;
 517         size_t i;
 518
 519         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 520                 return false;
 521
 522         switch (rule->func) {
 523         case KEY_CHECK:
 524                 if (!rule->keyrings)
 525                         return true;
 526
 527                 opt_list = rule->keyrings;
 528                 break;
 529         case CRITICAL_DATA:
 530                 if (!rule->label)
 531                         return true;
 532
 533                 opt_list = rule->label;
 534                 break;
 535         default:
 536                 return false;
 537         }
 538
 539         if (!func_data)
 540                 return false;
 541
 542         for (i = 0; i < opt_list->count; i++) {
 543                 if (!strcmp(opt_list->items[i], func_data)) {
 544                         matched = true;
 545                         break;
 546                 }
 547         }
 548
 549         return matched;
 550 }
 551
 552 /**
 553  * ima_match_rules - determine whether an inode matches the policy rule.
 554  * @rule: a pointer to a rule
 555  * @mnt_userns: user namespace of the mount the inode was found from
 556  * @inode: a pointer to an inode
 557  * @cred: a pointer to a credentials structure for user validation
 558  * @secid: the secid of the task to be validated
 559  * @func: LIM hook identifier
 560  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 561  * @func_data: func specific data, may be NULL
 562  *
 563  * Returns true on rule match, false on failure.
 564  */
 565 static bool ima_match_rules(struct ima_rule_entry *rule,
 566                             struct user_namespace *mnt_userns,
 567                             struct inode *inode, const struct cred *cred,
 568                             u32 secid, enum ima_hooks func, int mask,
 569                             const char *func_data)
 570 {
 571         int i;
 572         bool result = false;
 573         struct ima_rule_entry *lsm_rule = rule;
 574         bool rule_reinitialized = false;
 575
 576         if ((rule->flags & IMA_FUNC) &&
 577             (rule->func != func && func != POST_SETATTR))
 578                 return false;
 579
 580         switch (func) {
 581         case KEY_CHECK:
 582         case CRITICAL_DATA:
 583                 return ((rule->func == func) &&
 584                         ima_match_rule_data(rule, func_data, cred));
 585         default:
 586                 break;
 587         }
 588
 589         if ((rule->flags & IMA_MASK) &&
 590             (rule->mask != mask && func != POST_SETATTR))
 591                 return false;
 592         if ((rule->flags & IMA_INMASK) &&
 593             (!(rule->mask & mask) && func != POST_SETATTR))
 594                 return false;
 595         if ((rule->flags & IMA_FSMAGIC)
 596             && rule->fsmagic != inode->i_sb->s_magic)
 597                 return false;
 598         if ((rule->flags & IMA_FSNAME)
 599             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 600                 return false;
 601         if ((rule->flags & IMA_FSUUID) &&
 602             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 603                 return false;
 604         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 605                 return false;
 606         if (rule->flags & IMA_EUID) {
 607                 if (has_capability_noaudit(current, CAP_SETUID)) {
 608                         if (!rule->uid_op(cred->euid, rule->uid)
 609                             && !rule->uid_op(cred->suid, rule->uid)
 610                             && !rule->uid_op(cred->uid, rule->uid))
 611                                 return false;
 612                 } else if (!rule->uid_op(cred->euid, rule->uid))
 613                         return false;
 614         }
 615         if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
 616                 return false;
 617         if (rule->flags & IMA_EGID) {
 618                 if (has_capability_noaudit(current, CAP_SETGID)) {
 619                         if (!rule->gid_op(cred->egid, rule->gid)
 620                             && !rule->gid_op(cred->sgid, rule->gid)
 621                             && !rule->gid_op(cred->gid, rule->gid))
 622                                 return false;
 623                 } else if (!rule->gid_op(cred->egid, rule->gid))
 624                         return false;
 625         }
 626         if ((rule->flags & IMA_FOWNER) &&
 627             !rule->fowner_op(i_uid_into_vfsuid(mnt_userns, inode),
 628                              rule->fowner))
 629                 return false;
 630         if ((rule->flags & IMA_FGROUP) &&
 631             !rule->fgroup_op(i_gid_into_vfsgid(mnt_userns, inode),
 632                              rule->fgroup))
 633                 return false;
 634         for (i = 0; i < MAX_LSM_RULES; i++) {
 635                 int rc = 0;
 636                 u32 osid;
 637
 638                 if (!lsm_rule->lsm[i].rule) {
 639                         if (!lsm_rule->lsm[i].args_p)
 640                                 continue;
 641                         else
 642                                 return false;
 643                 }
 644
 645 retry:
 646                 switch (i) {
 647                 case LSM_OBJ_USER:
 648                 case LSM_OBJ_ROLE:
 649                 case LSM_OBJ_TYPE:
 650                         security_inode_getsecid(inode, &osid);
 651                         rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
 652                                                    Audit_equal,
 653                                                    lsm_rule->lsm[i].rule);
 654                         break;
 655                 case LSM_SUBJ_USER:
 656                 case LSM_SUBJ_ROLE:
 657                 case LSM_SUBJ_TYPE:
 658                         rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
 659                                                    Audit_equal,
 660                                                    lsm_rule->lsm[i].rule);
 661                         break;
 662                 default:
 663                         break;
 664                 }
 665
 666                 if (rc == -ESTALE && !rule_reinitialized) {
 667                         lsm_rule = ima_lsm_copy_rule(rule);
 668                         if (lsm_rule) {
 669                                 rule_reinitialized = true;
 670                                 goto retry;
 671                         }
 672                 }
 673                 if (!rc) {
 674                         result = false;
 675                         goto out;
 676                 }
 677         }
 678         result = true;
 679
 680 out:
 681         if (rule_reinitialized) {
 682                 for (i = 0; i < MAX_LSM_RULES; i++)
 683                         ima_filter_rule_free(lsm_rule->lsm[i].rule);
 684                 kfree(lsm_rule);
 685         }
 686         return result;
 687 }
 688
 689 /*
 690  * In addition to knowing that we need to appraise the file in general,
 691  * we need to differentiate between calling hooks, for hook specific rules.
 692  */
 693 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 694 {
 695         if (!(rule->flags & IMA_FUNC))
 696                 return IMA_FILE_APPRAISE;
 697
 698         switch (func) {
 699         case MMAP_CHECK:
 700                 return IMA_MMAP_APPRAISE;
 701         case BPRM_CHECK:
 702                 return IMA_BPRM_APPRAISE;
 703         case CREDS_CHECK:
 704                 return IMA_CREDS_APPRAISE;
 705         case FILE_CHECK:
 706         case POST_SETATTR:
 707                 return IMA_FILE_APPRAISE;
 708         case MODULE_CHECK ... MAX_CHECK - 1:
 709         default:
 710                 return IMA_READ_APPRAISE;
 711         }
 712 }
 713
 714 /**
 715  * ima_match_policy - decision based on LSM and other conditions
 716  * @mnt_userns: user namespace of the mount the inode was found from
 717  * @inode: pointer to an inode for which the policy decision is being made
 718  * @cred: pointer to a credentials structure for which the policy decision is
 719  *        being made
 720  * @secid: LSM secid of the task to be validated
 721  * @func: IMA hook identifier
 722  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 723  * @pcr: set the pcr to extend
 724  * @template_desc: the template that should be used for this rule
 725  * @func_data: func specific data, may be NULL
 726  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
 727  *
 728  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 729  * conditions.
 730  *
 731  * Since the IMA policy may be updated multiple times we need to lock the
 732  * list when walking it.  Reads are many orders of magnitude more numerous
 733  * than writes so ima_match_policy() is classical RCU candidate.
 734  */
 735 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 736                      const struct cred *cred, u32 secid, enum ima_hooks func,
 737                      int mask, int flags, int *pcr,
 738                      struct ima_template_desc **template_desc,
 739                      const char *func_data, unsigned int *allowed_algos)
 740 {
 741         struct ima_rule_entry *entry;
 742         int action = 0, actmask = flags | (flags << 1);
 743         struct list_head *ima_rules_tmp;
 744
 745         if (template_desc && !*template_desc)
 746                 *template_desc = ima_template_desc_current();
 747
 748         rcu_read_lock();
 749         ima_rules_tmp = rcu_dereference(ima_rules);
 750         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 751
 752                 if (!(entry->action & actmask))
 753                         continue;
 754
 755                 if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
 756                                      func, mask, func_data))
 757                         continue;
 758
 759                 action |= entry->flags & IMA_NONACTION_FLAGS;
 760
 761                 action |= entry->action & IMA_DO_MASK;
 762                 if (entry->action & IMA_APPRAISE) {
 763                         action |= get_subaction(entry, func);
 764                         action &= ~IMA_HASH;
 765                         if (ima_fail_unverifiable_sigs)
 766                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 767
 768                         if (allowed_algos &&
 769                             entry->flags & IMA_VALIDATE_ALGOS)
 770                                 *allowed_algos = entry->allowed_algos;
 771                 }
 772
 773                 if (entry->action & IMA_DO_MASK)
 774                         actmask &= ~(entry->action | entry->action << 1);
 775                 else
 776                         actmask &= ~(entry->action | entry->action >> 1);
 777
 778                 if ((pcr) && (entry->flags & IMA_PCR))
 779                         *pcr = entry->pcr;
 780
 781                 if (template_desc && entry->template)
 782                         *template_desc = entry->template;
 783
 784                 if (!actmask)
 785                         break;
 786         }
 787         rcu_read_unlock();
 788
 789         return action;
 790 }
 791
 792 /**
 793  * ima_update_policy_flags() - Update global IMA variables
 794  *
 795  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
 796  * based on the currently loaded policy.
 797  *
 798  * With ima_policy_flag, the decision to short circuit out of a function
 799  * or not call the function in the first place can be made earlier.
 800  *
 801  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
 802  * set of hash algorithms accepted when updating the security.ima xattr of
 803  * a file.
 804  *
 805  * Context: called after a policy update and at system initialization.
 806  */
 807 void ima_update_policy_flags(void)
 808 {
 809         struct ima_rule_entry *entry;
 810         int new_policy_flag = 0;
 811         struct list_head *ima_rules_tmp;
 812
 813         rcu_read_lock();
 814         ima_rules_tmp = rcu_dereference(ima_rules);
 815         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 816                 /*
 817                  * SETXATTR_CHECK rules do not implement a full policy check
 818                  * because rule checking would probably have an important
 819                  * performance impact on setxattr(). As a consequence, only one
 820                  * SETXATTR_CHECK can be active at a given time.
 821                  * Because we want to preserve that property, we set out to use
 822                  * atomic_cmpxchg. Either:
 823                  * - the atomic was non-zero: a setxattr hash policy is
 824                  *   already enforced, we do nothing
 825                  * - the atomic was zero: no setxattr policy was set, enable
 826                  *   the setxattr hash policy
 827                  */
 828                 if (entry->func == SETXATTR_CHECK) {
 829                         atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
 830                                        0, entry->allowed_algos);
 831                         /* SETXATTR_CHECK doesn't impact ima_policy_flag */
 832                         continue;
 833                 }
 834
 835                 if (entry->action & IMA_DO_MASK)
 836                         new_policy_flag |= entry->action;
 837         }
 838         rcu_read_unlock();
 839
 840         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 841         if (!ima_appraise)
 842                 new_policy_flag &= ~IMA_APPRAISE;
 843
 844         ima_policy_flag = new_policy_flag;
 845 }
 846
 847 static int ima_appraise_flag(enum ima_hooks func)
 848 {
 849         if (func == MODULE_CHECK)
 850                 return IMA_APPRAISE_MODULES;
 851         else if (func == FIRMWARE_CHECK)
 852                 return IMA_APPRAISE_FIRMWARE;
 853         else if (func == POLICY_CHECK)
 854                 return IMA_APPRAISE_POLICY;
 855         else if (func == KEXEC_KERNEL_CHECK)
 856                 return IMA_APPRAISE_KEXEC;
 857         return 0;
 858 }
 859
 860 static void add_rules(struct ima_rule_entry *entries, int count,
 861                       enum policy_rule_list policy_rule)
 862 {
 863         int i = 0;
 864
 865         for (i = 0; i < count; i++) {
 866                 struct ima_rule_entry *entry;
 867
 868                 if (policy_rule & IMA_DEFAULT_POLICY)
 869                         list_add_tail(&entries[i].list, &ima_default_rules);
 870
 871                 if (policy_rule & IMA_CUSTOM_POLICY) {
 872                         entry = kmemdup(&entries[i], sizeof(*entry),
 873                                         GFP_KERNEL);
 874                         if (!entry)
 875                                 continue;
 876
 877                         list_add_tail(&entry->list, &ima_policy_rules);
 878                 }
 879                 if (entries[i].action == APPRAISE) {
 880                         if (entries != build_appraise_rules)
 881                                 temp_ima_appraise |=
 882                                         ima_appraise_flag(entries[i].func);
 883                         else
 884                                 build_ima_appraise |=
 885                                         ima_appraise_flag(entries[i].func);
 886                 }
 887         }
 888 }
 889
 890 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 891
 892 static int __init ima_init_arch_policy(void)
 893 {
 894         const char * const *arch_rules;
 895         const char * const *rules;
 896         int arch_entries = 0;
 897         int i = 0;
 898
 899         arch_rules = arch_get_ima_policy();
 900         if (!arch_rules)
 901                 return arch_entries;
 902
 903         /* Get number of rules */
 904         for (rules = arch_rules; *rules != NULL; rules++)
 905                 arch_entries++;
 906
 907         arch_policy_entry = kcalloc(arch_entries + 1,
 908                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 909         if (!arch_policy_entry)
 910                 return 0;
 911
 912         /* Convert each policy string rules to struct ima_rule_entry format */
 913         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 914                 char rule[255];
 915                 int result;
 916
 917                 result = strscpy(rule, *rules, sizeof(rule));
 918
 919                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 920                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 921                 if (result) {
 922                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 923                                 rule);
 924                         memset(&arch_policy_entry[i], 0,
 925                                sizeof(*arch_policy_entry));
 926                         continue;
 927                 }
 928                 i++;
 929         }
 930         return i;
 931 }
 932
 933 /**
 934  * ima_init_policy - initialize the default measure rules.
 935  *
 936  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
 937  */
 938 void __init ima_init_policy(void)
 939 {
 940         int build_appraise_entries, arch_entries;
 941
 942         /* if !ima_policy, we load NO default rules */
 943         if (ima_policy)
 944                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 945                           IMA_DEFAULT_POLICY);
 946
 947         switch (ima_policy) {
 948         case ORIGINAL_TCB:
 949                 add_rules(original_measurement_rules,
 950                           ARRAY_SIZE(original_measurement_rules),
 951                           IMA_DEFAULT_POLICY);
 952                 break;
 953         case DEFAULT_TCB:
 954                 add_rules(default_measurement_rules,
 955                           ARRAY_SIZE(default_measurement_rules),
 956                           IMA_DEFAULT_POLICY);
 957                 break;
 958         default:
 959                 break;
 960         }
 961
 962         /*
 963          * Based on runtime secure boot flags, insert arch specific measurement
 964          * and appraise rules requiring file signatures for both the initial
 965          * and custom policies, prior to other appraise rules.
 966          * (Highest priority)
 967          */
 968         arch_entries = ima_init_arch_policy();
 969         if (!arch_entries)
 970                 pr_info("No architecture policies found\n");
 971         else
 972                 add_rules(arch_policy_entry, arch_entries,
 973                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 974
 975         /*
 976          * Insert the builtin "secure_boot" policy rules requiring file
 977          * signatures, prior to other appraise rules.
 978          */
 979         if (ima_use_secure_boot)
 980                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 981                           IMA_DEFAULT_POLICY);
 982
 983         /*
 984          * Insert the build time appraise rules requiring file signatures
 985          * for both the initial and custom policies, prior to other appraise
 986          * rules. As the secure boot rules includes all of the build time
 987          * rules, include either one or the other set of rules, but not both.
 988          */
 989         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 990         if (build_appraise_entries) {
 991                 if (ima_use_secure_boot)
 992                         add_rules(build_appraise_rules, build_appraise_entries,
 993                                   IMA_CUSTOM_POLICY);
 994                 else
 995                         add_rules(build_appraise_rules, build_appraise_entries,
 996                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 997         }
 998
 999         if (ima_use_appraise_tcb)
1000                 add_rules(default_appraise_rules,
1001                           ARRAY_SIZE(default_appraise_rules),
1002                           IMA_DEFAULT_POLICY);
1003
1004         if (ima_use_critical_data)
1005                 add_rules(critical_data_rules,
1006                           ARRAY_SIZE(critical_data_rules),
1007                           IMA_DEFAULT_POLICY);
1008
1009         atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
1010
1011         ima_update_policy_flags();
1012 }
1013
1014 /* Make sure we have a valid policy, at least containing some rules. */
1015 int ima_check_policy(void)
1016 {
1017         if (list_empty(&ima_temp_rules))
1018                 return -EINVAL;
1019         return 0;
1020 }
1021
1022 /**
1023  * ima_update_policy - update default_rules with new measure rules
1024  *
1025  * Called on file .release to update the default rules with a complete new
1026  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
1027  * they make a queue.  The policy may be updated multiple times and this is the
1028  * RCU updater.
1029  *
1030  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
1031  * we switch from the default policy to user defined.
1032  */
1033 void ima_update_policy(void)
1034 {
1035         struct list_head *policy = &ima_policy_rules;
1036
1037         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
1038
1039         if (ima_rules != (struct list_head __rcu *)policy) {
1040                 ima_policy_flag = 0;
1041
1042                 rcu_assign_pointer(ima_rules, policy);
1043                 /*
1044                  * IMA architecture specific policy rules are specified
1045                  * as strings and converted to an array of ima_entry_rules
1046                  * on boot.  After loading a custom policy, free the
1047                  * architecture specific rules stored as an array.
1048                  */
1049                 kfree(arch_policy_entry);
1050         }
1051         ima_update_policy_flags();
1052
1053         /* Custom IMA policy has been loaded */
1054         ima_process_queued_keys();
1055 }
1056
1057 /* Keep the enumeration in sync with the policy_tokens! */
1058 enum policy_opt {
1059         Opt_measure, Opt_dont_measure,
1060         Opt_appraise, Opt_dont_appraise,
1061         Opt_audit, Opt_hash, Opt_dont_hash,
1062         Opt_obj_user, Opt_obj_role, Opt_obj_type,
1063         Opt_subj_user, Opt_subj_role, Opt_subj_type,
1064         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1065         Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1066         Opt_fowner_eq, Opt_fgroup_eq,
1067         Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1068         Opt_fowner_gt, Opt_fgroup_gt,
1069         Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1070         Opt_fowner_lt, Opt_fgroup_lt,
1071         Opt_digest_type,
1072         Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1073         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1074         Opt_label, Opt_err
1075 };
1076
1077 static const match_table_t policy_tokens = {
1078         {Opt_measure, "measure"},
1079         {Opt_dont_measure, "dont_measure"},
1080         {Opt_appraise, "appraise"},
1081         {Opt_dont_appraise, "dont_appraise"},
1082         {Opt_audit, "audit"},
1083         {Opt_hash, "hash"},
1084         {Opt_dont_hash, "dont_hash"},
1085         {Opt_obj_user, "obj_user=%s"},
1086         {Opt_obj_role, "obj_role=%s"},
1087         {Opt_obj_type, "obj_type=%s"},
1088         {Opt_subj_user, "subj_user=%s"},
1089         {Opt_subj_role, "subj_role=%s"},
1090         {Opt_subj_type, "subj_type=%s"},
1091         {Opt_func, "func=%s"},
1092         {Opt_mask, "mask=%s"},
1093         {Opt_fsmagic, "fsmagic=%s"},
1094         {Opt_fsname, "fsname=%s"},
1095         {Opt_fsuuid, "fsuuid=%s"},
1096         {Opt_uid_eq, "uid=%s"},
1097         {Opt_euid_eq, "euid=%s"},
1098         {Opt_gid_eq, "gid=%s"},
1099         {Opt_egid_eq, "egid=%s"},
1100         {Opt_fowner_eq, "fowner=%s"},
1101         {Opt_fgroup_eq, "fgroup=%s"},
1102         {Opt_uid_gt, "uid>%s"},
1103         {Opt_euid_gt, "euid>%s"},
1104         {Opt_gid_gt, "gid>%s"},
1105         {Opt_egid_gt, "egid>%s"},
1106         {Opt_fowner_gt, "fowner>%s"},
1107         {Opt_fgroup_gt, "fgroup>%s"},
1108         {Opt_uid_lt, "uid<%s"},
1109         {Opt_euid_lt, "euid<%s"},
1110         {Opt_gid_lt, "gid<%s"},
1111         {Opt_egid_lt, "egid<%s"},
1112         {Opt_fowner_lt, "fowner<%s"},
1113         {Opt_fgroup_lt, "fgroup<%s"},
1114         {Opt_digest_type, "digest_type=%s"},
1115         {Opt_appraise_type, "appraise_type=%s"},
1116         {Opt_appraise_flag, "appraise_flag=%s"},
1117         {Opt_appraise_algos, "appraise_algos=%s"},
1118         {Opt_permit_directio, "permit_directio"},
1119         {Opt_pcr, "pcr=%s"},
1120         {Opt_template, "template=%s"},
1121         {Opt_keyrings, "keyrings=%s"},
1122         {Opt_label, "label=%s"},
1123         {Opt_err, NULL}
1124 };
1125
1126 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1127                              substring_t *args, int lsm_rule, int audit_type)
1128 {
1129         int result;
1130
1131         if (entry->lsm[lsm_rule].rule)
1132                 return -EINVAL;
1133
1134         entry->lsm[lsm_rule].args_p = match_strdup(args);
1135         if (!entry->lsm[lsm_rule].args_p)
1136                 return -ENOMEM;
1137
1138         entry->lsm[lsm_rule].type = audit_type;
1139         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1140                                       entry->lsm[lsm_rule].args_p,
1141                                       &entry->lsm[lsm_rule].rule);
1142         if (!entry->lsm[lsm_rule].rule) {
1143                 pr_warn("rule for LSM \'%s\' is undefined\n",
1144                         entry->lsm[lsm_rule].args_p);
1145
1146                 if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1147                         kfree(entry->lsm[lsm_rule].args_p);
1148                         entry->lsm[lsm_rule].args_p = NULL;
1149                         result = -EINVAL;
1150                 } else
1151                         result = 0;
1152         }
1153
1154         return result;
1155 }
1156
1157 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1158                               enum policy_opt rule_operator)
1159 {
1160         if (!ab)
1161                 return;
1162
1163         switch (rule_operator) {
1164         case Opt_uid_gt:
1165         case Opt_euid_gt:
1166         case Opt_gid_gt:
1167         case Opt_egid_gt:
1168         case Opt_fowner_gt:
1169         case Opt_fgroup_gt:
1170                 audit_log_format(ab, "%s>", key);
1171                 break;
1172         case Opt_uid_lt:
1173         case Opt_euid_lt:
1174         case Opt_gid_lt:
1175         case Opt_egid_lt:
1176         case Opt_fowner_lt:
1177         case Opt_fgroup_lt:
1178                 audit_log_format(ab, "%s<", key);
1179                 break;
1180         default:
1181                 audit_log_format(ab, "%s=", key);
1182         }
1183         audit_log_format(ab, "%s ", value);
1184 }
1185 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1186 {
1187         ima_log_string_op(ab, key, value, Opt_err);
1188 }
1189
1190 /*
1191  * Validating the appended signature included in the measurement list requires
1192  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1193  * field). Therefore, notify the user if they have the 'modsig' field but not
1194  * the 'd-modsig' field in the template.
1195  */
1196 static void check_template_modsig(const struct ima_template_desc *template)
1197 {
1198 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1199         bool has_modsig, has_dmodsig;
1200         static bool checked;
1201         int i;
1202
1203         /* We only need to notify the user once. */
1204         if (checked)
1205                 return;
1206
1207         has_modsig = has_dmodsig = false;
1208         for (i = 0; i < template->num_fields; i++) {
1209                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1210                         has_modsig = true;
1211                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1212                         has_dmodsig = true;
1213         }
1214
1215         if (has_modsig && !has_dmodsig)
1216                 pr_notice(MSG);
1217
1218         checked = true;
1219 #undef MSG
1220 }
1221
1222 /*
1223  * Warn if the template does not contain the given field.
1224  */
1225 static void check_template_field(const struct ima_template_desc *template,
1226                                  const char *field, const char *msg)
1227 {
1228         int i;
1229
1230         for (i = 0; i < template->num_fields; i++)
1231                 if (!strcmp(template->fields[i]->field_id, field))
1232                         return;
1233
1234         pr_notice_once("%s", msg);
1235 }
1236
1237 static bool ima_validate_rule(struct ima_rule_entry *entry)
1238 {
1239         /* Ensure that the action is set and is compatible with the flags */
1240         if (entry->action == UNKNOWN)
1241                 return false;
1242
1243         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1244                 return false;
1245
1246         if (entry->action != APPRAISE &&
1247             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1248                             IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1249                 return false;
1250
1251         /*
1252          * The IMA_FUNC bit must be set if and only if there's a valid hook
1253          * function specified, and vice versa. Enforcing this property allows
1254          * for the NONE case below to validate a rule without an explicit hook
1255          * function.
1256          */
1257         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1258             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1259                 return false;
1260
1261         /*
1262          * Ensure that the hook function is compatible with the other
1263          * components of the rule
1264          */
1265         switch (entry->func) {
1266         case NONE:
1267         case FILE_CHECK:
1268         case MMAP_CHECK:
1269         case BPRM_CHECK:
1270         case CREDS_CHECK:
1271         case POST_SETATTR:
1272         case FIRMWARE_CHECK:
1273         case POLICY_CHECK:
1274                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1275                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1276                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1277                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1278                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1279                                      IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1280                                      IMA_VERITY_REQUIRED))
1281                         return false;
1282
1283                 break;
1284         case MODULE_CHECK:
1285         case KEXEC_KERNEL_CHECK:
1286         case KEXEC_INITRAMFS_CHECK:
1287                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1288                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1289                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1290                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1291                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1292                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1293                                      IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1294                         return false;
1295
1296                 break;
1297         case KEXEC_CMDLINE:
1298                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1299                         return false;
1300
1301                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1302                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1303                                      IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1304                                      IMA_FGROUP))
1305                         return false;
1306
1307                 break;
1308         case KEY_CHECK:
1309                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1310                         return false;
1311
1312                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1313                                      IMA_KEYRINGS))
1314                         return false;
1315
1316                 if (ima_rule_contains_lsm_cond(entry))
1317                         return false;
1318
1319                 break;
1320         case CRITICAL_DATA:
1321                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1322                         return false;
1323
1324                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1325                                      IMA_LABEL))
1326                         return false;
1327
1328                 if (ima_rule_contains_lsm_cond(entry))
1329                         return false;
1330
1331                 break;
1332         case SETXATTR_CHECK:
1333                 /* any action other than APPRAISE is unsupported */
1334                 if (entry->action != APPRAISE)
1335                         return false;
1336
1337                 /* SETXATTR_CHECK requires an appraise_algos parameter */
1338                 if (!(entry->flags & IMA_VALIDATE_ALGOS))
1339                         return false;
1340
1341                 /*
1342                  * full policies are not supported, they would have too
1343                  * much of a performance impact
1344                  */
1345                 if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1346                         return false;
1347
1348                 break;
1349         default:
1350                 return false;
1351         }
1352
1353         /* Ensure that combinations of flags are compatible with each other */
1354         if (entry->flags & IMA_CHECK_BLACKLIST &&
1355             !(entry->flags & IMA_MODSIG_ALLOWED))
1356                 return false;
1357
1358         /*
1359          * Unlike for regular IMA 'appraise' policy rules where security.ima
1360          * xattr may contain either a file hash or signature, the security.ima
1361          * xattr for fsverity must contain a file signature (sigv3).  Ensure
1362          * that 'appraise' rules for fsverity require file signatures by
1363          * checking the IMA_DIGSIG_REQUIRED flag is set.
1364          */
1365         if (entry->action == APPRAISE &&
1366             (entry->flags & IMA_VERITY_REQUIRED) &&
1367             !(entry->flags & IMA_DIGSIG_REQUIRED))
1368                 return false;
1369
1370         return true;
1371 }
1372
1373 static unsigned int ima_parse_appraise_algos(char *arg)
1374 {
1375         unsigned int res = 0;
1376         int idx;
1377         char *token;
1378
1379         while ((token = strsep(&arg, ",")) != NULL) {
1380                 idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1381
1382                 if (idx < 0) {
1383                         pr_err("unknown hash algorithm \"%s\"",
1384                                token);
1385                         return 0;
1386                 }
1387
1388                 if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1389                         pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1390                                token);
1391                         return 0;
1392                 }
1393
1394                 /* Add the hash algorithm to the 'allowed' bitfield */
1395                 res |= (1U << idx);
1396         }
1397
1398         return res;
1399 }
1400
1401 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1402 {
1403         struct audit_buffer *ab;
1404         char *from;
1405         char *p;
1406         bool eid_token; /* either euid or egid */
1407         struct ima_template_desc *template_desc;
1408         int result = 0;
1409
1410         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1411                                        AUDIT_INTEGRITY_POLICY_RULE);
1412
1413         entry->uid = INVALID_UID;
1414         entry->gid = INVALID_GID;
1415         entry->fowner = INVALID_UID;
1416         entry->fgroup = INVALID_GID;
1417         entry->uid_op = &uid_eq;
1418         entry->gid_op = &gid_eq;
1419         entry->fowner_op = &vfsuid_eq_kuid;
1420         entry->fgroup_op = &vfsgid_eq_kgid;
1421         entry->action = UNKNOWN;
1422         while ((p = strsep(&rule, " \t")) != NULL) {
1423                 substring_t args[MAX_OPT_ARGS];
1424                 int token;
1425                 unsigned long lnum;
1426
1427                 if (result < 0)
1428                         break;
1429                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1430                         continue;
1431                 token = match_token(p, policy_tokens, args);
1432                 switch (token) {
1433                 case Opt_measure:
1434                         ima_log_string(ab, "action", "measure");
1435
1436                         if (entry->action != UNKNOWN)
1437                                 result = -EINVAL;
1438
1439                         entry->action = MEASURE;
1440                         break;
1441                 case Opt_dont_measure:
1442                         ima_log_string(ab, "action", "dont_measure");
1443
1444                         if (entry->action != UNKNOWN)
1445                                 result = -EINVAL;
1446
1447                         entry->action = DONT_MEASURE;
1448                         break;
1449                 case Opt_appraise:
1450                         ima_log_string(ab, "action", "appraise");
1451
1452                         if (entry->action != UNKNOWN)
1453                                 result = -EINVAL;
1454
1455                         entry->action = APPRAISE;
1456                         break;
1457                 case Opt_dont_appraise:
1458                         ima_log_string(ab, "action", "dont_appraise");
1459
1460                         if (entry->action != UNKNOWN)
1461                                 result = -EINVAL;
1462
1463                         entry->action = DONT_APPRAISE;
1464                         break;
1465                 case Opt_audit:
1466                         ima_log_string(ab, "action", "audit");
1467
1468                         if (entry->action != UNKNOWN)
1469                                 result = -EINVAL;
1470
1471                         entry->action = AUDIT;
1472                         break;
1473                 case Opt_hash:
1474                         ima_log_string(ab, "action", "hash");
1475
1476                         if (entry->action != UNKNOWN)
1477                                 result = -EINVAL;
1478
1479                         entry->action = HASH;
1480                         break;
1481                 case Opt_dont_hash:
1482                         ima_log_string(ab, "action", "dont_hash");
1483
1484                         if (entry->action != UNKNOWN)
1485                                 result = -EINVAL;
1486
1487                         entry->action = DONT_HASH;
1488                         break;
1489                 case Opt_func:
1490                         ima_log_string(ab, "func", args[0].from);
1491
1492                         if (entry->func)
1493                                 result = -EINVAL;
1494
1495                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1496                                 entry->func = FILE_CHECK;
1497                         /* PATH_CHECK is for backwards compat */
1498                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1499                                 entry->func = FILE_CHECK;
1500                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1501                                 entry->func = MODULE_CHECK;
1502                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1503                                 entry->func = FIRMWARE_CHECK;
1504                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1505                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1506                                 entry->func = MMAP_CHECK;
1507                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1508                                 entry->func = BPRM_CHECK;
1509                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1510                                 entry->func = CREDS_CHECK;
1511                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1512                                  0)
1513                                 entry->func = KEXEC_KERNEL_CHECK;
1514                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1515                                  == 0)
1516                                 entry->func = KEXEC_INITRAMFS_CHECK;
1517                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1518                                 entry->func = POLICY_CHECK;
1519                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1520                                 entry->func = KEXEC_CMDLINE;
1521                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1522                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1523                                 entry->func = KEY_CHECK;
1524                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1525                                 entry->func = CRITICAL_DATA;
1526                         else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1527                                 entry->func = SETXATTR_CHECK;
1528                         else
1529                                 result = -EINVAL;
1530                         if (!result)
1531                                 entry->flags |= IMA_FUNC;
1532                         break;
1533                 case Opt_mask:
1534                         ima_log_string(ab, "mask", args[0].from);
1535
1536                         if (entry->mask)
1537                                 result = -EINVAL;
1538
1539                         from = args[0].from;
1540                         if (*from == '^')
1541                                 from++;
1542
1543                         if ((strcmp(from, "MAY_EXEC")) == 0)
1544                                 entry->mask = MAY_EXEC;
1545                         else if (strcmp(from, "MAY_WRITE") == 0)
1546                                 entry->mask = MAY_WRITE;
1547                         else if (strcmp(from, "MAY_READ") == 0)
1548                                 entry->mask = MAY_READ;
1549                         else if (strcmp(from, "MAY_APPEND") == 0)
1550                                 entry->mask = MAY_APPEND;
1551                         else
1552                                 result = -EINVAL;
1553                         if (!result)
1554                                 entry->flags |= (*args[0].from == '^')
1555                                      ? IMA_INMASK : IMA_MASK;
1556                         break;
1557                 case Opt_fsmagic:
1558                         ima_log_string(ab, "fsmagic", args[0].from);
1559
1560                         if (entry->fsmagic) {
1561                                 result = -EINVAL;
1562                                 break;
1563                         }
1564
1565                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1566                         if (!result)
1567                                 entry->flags |= IMA_FSMAGIC;
1568                         break;
1569                 case Opt_fsname:
1570                         ima_log_string(ab, "fsname", args[0].from);
1571
1572                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1573                         if (!entry->fsname) {
1574                                 result = -ENOMEM;
1575                                 break;
1576                         }
1577                         result = 0;
1578                         entry->flags |= IMA_FSNAME;
1579                         break;
1580                 case Opt_keyrings:
1581                         ima_log_string(ab, "keyrings", args[0].from);
1582
1583                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1584                             entry->keyrings) {
1585                                 result = -EINVAL;
1586                                 break;
1587                         }
1588
1589                         entry->keyrings = ima_alloc_rule_opt_list(args);
1590                         if (IS_ERR(entry->keyrings)) {
1591                                 result = PTR_ERR(entry->keyrings);
1592                                 entry->keyrings = NULL;
1593                                 break;
1594                         }
1595
1596                         entry->flags |= IMA_KEYRINGS;
1597                         break;
1598                 case Opt_label:
1599                         ima_log_string(ab, "label", args[0].from);
1600
1601                         if (entry->label) {
1602                                 result = -EINVAL;
1603                                 break;
1604                         }
1605
1606                         entry->label = ima_alloc_rule_opt_list(args);
1607                         if (IS_ERR(entry->label)) {
1608                                 result = PTR_ERR(entry->label);
1609                                 entry->label = NULL;
1610                                 break;
1611                         }
1612
1613                         entry->flags |= IMA_LABEL;
1614                         break;
1615                 case Opt_fsuuid:
1616                         ima_log_string(ab, "fsuuid", args[0].from);
1617
1618                         if (!uuid_is_null(&entry->fsuuid)) {
1619                                 result = -EINVAL;
1620                                 break;
1621                         }
1622
1623                         result = uuid_parse(args[0].from, &entry->fsuuid);
1624                         if (!result)
1625                                 entry->flags |= IMA_FSUUID;
1626                         break;
1627                 case Opt_uid_gt:
1628                 case Opt_euid_gt:
1629                         entry->uid_op = &uid_gt;
1630                         fallthrough;
1631                 case Opt_uid_lt:
1632                 case Opt_euid_lt:
1633                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1634                                 entry->uid_op = &uid_lt;
1635                         fallthrough;
1636                 case Opt_uid_eq:
1637                 case Opt_euid_eq:
1638                         eid_token = (token == Opt_euid_eq) ||
1639                                     (token == Opt_euid_gt) ||
1640                                     (token == Opt_euid_lt);
1641
1642                         ima_log_string_op(ab, eid_token ? "euid" : "uid",
1643                                           args[0].from, token);
1644
1645                         if (uid_valid(entry->uid)) {
1646                                 result = -EINVAL;
1647                                 break;
1648                         }
1649
1650                         result = kstrtoul(args[0].from, 10, &lnum);
1651                         if (!result) {
1652                                 entry->uid = make_kuid(current_user_ns(),
1653                                                        (uid_t) lnum);
1654                                 if (!uid_valid(entry->uid) ||
1655                                     (uid_t)lnum != lnum)
1656                                         result = -EINVAL;
1657                                 else
1658                                         entry->flags |= eid_token
1659                                             ? IMA_EUID : IMA_UID;
1660                         }
1661                         break;
1662                 case Opt_gid_gt:
1663                 case Opt_egid_gt:
1664                         entry->gid_op = &gid_gt;
1665                         fallthrough;
1666                 case Opt_gid_lt:
1667                 case Opt_egid_lt:
1668                         if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1669                                 entry->gid_op = &gid_lt;
1670                         fallthrough;
1671                 case Opt_gid_eq:
1672                 case Opt_egid_eq:
1673                         eid_token = (token == Opt_egid_eq) ||
1674                                     (token == Opt_egid_gt) ||
1675                                     (token == Opt_egid_lt);
1676
1677                         ima_log_string_op(ab, eid_token ? "egid" : "gid",
1678                                           args[0].from, token);
1679
1680                         if (gid_valid(entry->gid)) {
1681                                 result = -EINVAL;
1682                                 break;
1683                         }
1684
1685                         result = kstrtoul(args[0].from, 10, &lnum);
1686                         if (!result) {
1687                                 entry->gid = make_kgid(current_user_ns(),
1688                                                        (gid_t)lnum);
1689                                 if (!gid_valid(entry->gid) ||
1690                                     (((gid_t)lnum) != lnum))
1691                                         result = -EINVAL;
1692                                 else
1693                                         entry->flags |= eid_token
1694                                             ? IMA_EGID : IMA_GID;
1695                         }
1696                         break;
1697                 case Opt_fowner_gt:
1698                         entry->fowner_op = &vfsuid_gt_kuid;
1699                         fallthrough;
1700                 case Opt_fowner_lt:
1701                         if (token == Opt_fowner_lt)
1702                                 entry->fowner_op = &vfsuid_lt_kuid;
1703                         fallthrough;
1704                 case Opt_fowner_eq:
1705                         ima_log_string_op(ab, "fowner", args[0].from, token);
1706
1707                         if (uid_valid(entry->fowner)) {
1708                                 result = -EINVAL;
1709                                 break;
1710                         }
1711
1712                         result = kstrtoul(args[0].from, 10, &lnum);
1713                         if (!result) {
1714                                 entry->fowner = make_kuid(current_user_ns(),
1715                                                           (uid_t)lnum);
1716                                 if (!uid_valid(entry->fowner) ||
1717                                     (((uid_t)lnum) != lnum))
1718                                         result = -EINVAL;
1719                                 else
1720                                         entry->flags |= IMA_FOWNER;
1721                         }
1722                         break;
1723                 case Opt_fgroup_gt:
1724                         entry->fgroup_op = &vfsgid_gt_kgid;
1725                         fallthrough;
1726                 case Opt_fgroup_lt:
1727                         if (token == Opt_fgroup_lt)
1728                                 entry->fgroup_op = &vfsgid_lt_kgid;
1729                         fallthrough;
1730                 case Opt_fgroup_eq:
1731                         ima_log_string_op(ab, "fgroup", args[0].from, token);
1732
1733                         if (gid_valid(entry->fgroup)) {
1734                                 result = -EINVAL;
1735                                 break;
1736                         }
1737
1738                         result = kstrtoul(args[0].from, 10, &lnum);
1739                         if (!result) {
1740                                 entry->fgroup = make_kgid(current_user_ns(),
1741                                                           (gid_t)lnum);
1742                                 if (!gid_valid(entry->fgroup) ||
1743                                     (((gid_t)lnum) != lnum))
1744                                         result = -EINVAL;
1745                                 else
1746                                         entry->flags |= IMA_FGROUP;
1747                         }
1748                         break;
1749                 case Opt_obj_user:
1750                         ima_log_string(ab, "obj_user", args[0].from);
1751                         result = ima_lsm_rule_init(entry, args,
1752                                                    LSM_OBJ_USER,
1753                                                    AUDIT_OBJ_USER);
1754                         break;
1755                 case Opt_obj_role:
1756                         ima_log_string(ab, "obj_role", args[0].from);
1757                         result = ima_lsm_rule_init(entry, args,
1758                                                    LSM_OBJ_ROLE,
1759                                                    AUDIT_OBJ_ROLE);
1760                         break;
1761                 case Opt_obj_type:
1762                         ima_log_string(ab, "obj_type", args[0].from);
1763                         result = ima_lsm_rule_init(entry, args,
1764                                                    LSM_OBJ_TYPE,
1765                                                    AUDIT_OBJ_TYPE);
1766                         break;
1767                 case Opt_subj_user:
1768                         ima_log_string(ab, "subj_user", args[0].from);
1769                         result = ima_lsm_rule_init(entry, args,
1770                                                    LSM_SUBJ_USER,
1771                                                    AUDIT_SUBJ_USER);
1772                         break;
1773                 case Opt_subj_role:
1774                         ima_log_string(ab, "subj_role", args[0].from);
1775                         result = ima_lsm_rule_init(entry, args,
1776                                                    LSM_SUBJ_ROLE,
1777                                                    AUDIT_SUBJ_ROLE);
1778                         break;
1779                 case Opt_subj_type:
1780                         ima_log_string(ab, "subj_type", args[0].from);
1781                         result = ima_lsm_rule_init(entry, args,
1782                                                    LSM_SUBJ_TYPE,
1783                                                    AUDIT_SUBJ_TYPE);
1784                         break;
1785                 case Opt_digest_type:
1786                         ima_log_string(ab, "digest_type", args[0].from);
1787                         if (entry->flags & IMA_DIGSIG_REQUIRED)
1788                                 result = -EINVAL;
1789                         else if ((strcmp(args[0].from, "verity")) == 0)
1790                                 entry->flags |= IMA_VERITY_REQUIRED;
1791                         else
1792                                 result = -EINVAL;
1793                         break;
1794                 case Opt_appraise_type:
1795                         ima_log_string(ab, "appraise_type", args[0].from);
1796
1797                         if ((strcmp(args[0].from, "imasig")) == 0) {
1798                                 if (entry->flags & IMA_VERITY_REQUIRED)
1799                                         result = -EINVAL;
1800                                 else
1801                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1802                         } else if (strcmp(args[0].from, "sigv3") == 0) {
1803                                 /* Only fsverity supports sigv3 for now */
1804                                 if (entry->flags & IMA_VERITY_REQUIRED)
1805                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1806                                 else
1807                                         result = -EINVAL;
1808                         } else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1809                                  strcmp(args[0].from, "imasig|modsig") == 0) {
1810                                 if (entry->flags & IMA_VERITY_REQUIRED)
1811                                         result = -EINVAL;
1812                                 else
1813                                         entry->flags |= IMA_DIGSIG_REQUIRED |
1814                                                 IMA_MODSIG_ALLOWED;
1815                         } else {
1816                                 result = -EINVAL;
1817                         }
1818                         break;
1819                 case Opt_appraise_flag:
1820                         ima_log_string(ab, "appraise_flag", args[0].from);
1821                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1822                             strstr(args[0].from, "blacklist"))
1823                                 entry->flags |= IMA_CHECK_BLACKLIST;
1824                         else
1825                                 result = -EINVAL;
1826                         break;
1827                 case Opt_appraise_algos:
1828                         ima_log_string(ab, "appraise_algos", args[0].from);
1829
1830                         if (entry->allowed_algos) {
1831                                 result = -EINVAL;
1832                                 break;
1833                         }
1834
1835                         entry->allowed_algos =
1836                                 ima_parse_appraise_algos(args[0].from);
1837                         /* invalid or empty list of algorithms */
1838                         if (!entry->allowed_algos) {
1839                                 result = -EINVAL;
1840                                 break;
1841                         }
1842
1843                         entry->flags |= IMA_VALIDATE_ALGOS;
1844
1845                         break;
1846                 case Opt_permit_directio:
1847                         entry->flags |= IMA_PERMIT_DIRECTIO;
1848                         break;
1849                 case Opt_pcr:
1850                         ima_log_string(ab, "pcr", args[0].from);
1851
1852                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1853                         if (result || INVALID_PCR(entry->pcr))
1854                                 result = -EINVAL;
1855                         else
1856                                 entry->flags |= IMA_PCR;
1857
1858                         break;
1859                 case Opt_template:
1860                         ima_log_string(ab, "template", args[0].from);
1861                         if (entry->action != MEASURE) {
1862                                 result = -EINVAL;
1863                                 break;
1864                         }
1865                         template_desc = lookup_template_desc(args[0].from);
1866                         if (!template_desc || entry->template) {
1867                                 result = -EINVAL;
1868                                 break;
1869                         }
1870
1871                         /*
1872                          * template_desc_init_fields() does nothing if
1873                          * the template is already initialised, so
1874                          * it's safe to do this unconditionally
1875                          */
1876                         template_desc_init_fields(template_desc->fmt,
1877                                                  &(template_desc->fields),
1878                                                  &(template_desc->num_fields));
1879                         entry->template = template_desc;
1880                         break;
1881                 case Opt_err:
1882                         ima_log_string(ab, "UNKNOWN", p);
1883                         result = -EINVAL;
1884                         break;
1885                 }
1886         }
1887         if (!result && !ima_validate_rule(entry))
1888                 result = -EINVAL;
1889         else if (entry->action == APPRAISE)
1890                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1891
1892         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1893                 template_desc = entry->template ? entry->template :
1894                                                   ima_template_desc_current();
1895                 check_template_modsig(template_desc);
1896         }
1897
1898         /* d-ngv2 template field recommended for unsigned fs-verity digests */
1899         if (!result && entry->action == MEASURE &&
1900             entry->flags & IMA_VERITY_REQUIRED) {
1901                 template_desc = entry->template ? entry->template :
1902                                                   ima_template_desc_current();
1903                 check_template_field(template_desc, "d-ngv2",
1904                                      "verity rules should include d-ngv2");
1905         }
1906
1907         audit_log_format(ab, "res=%d", !result);
1908         audit_log_end(ab);
1909         return result;
1910 }
1911
1912 /**
1913  * ima_parse_add_rule - add a rule to ima_policy_rules
1914  * @rule - ima measurement policy rule
1915  *
1916  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1917  * Returns the length of the rule parsed, an error code on failure
1918  */
1919 ssize_t ima_parse_add_rule(char *rule)
1920 {
1921         static const char op[] = "update_policy";
1922         char *p;
1923         struct ima_rule_entry *entry;
1924         ssize_t result, len;
1925         int audit_info = 0;
1926
1927         p = strsep(&rule, "\n");
1928         len = strlen(p) + 1;
1929         p += strspn(p, " \t");
1930
1931         if (*p == '#' || *p == '\0')
1932                 return len;
1933
1934         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1935         if (!entry) {
1936                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1937                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1938                 return -ENOMEM;
1939         }
1940
1941         INIT_LIST_HEAD(&entry->list);
1942
1943         result = ima_parse_rule(p, entry);
1944         if (result) {
1945                 ima_free_rule(entry);
1946                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1947                                     NULL, op, "invalid-policy", result,
1948                                     audit_info);
1949                 return result;
1950         }
1951
1952         list_add_tail(&entry->list, &ima_temp_rules);
1953
1954         return len;
1955 }
1956
1957 /**
1958  * ima_delete_rules() called to cleanup invalid in-flight policy.
1959  * We don't need locking as we operate on the temp list, which is
1960  * different from the active one.  There is also only one user of
1961  * ima_delete_rules() at a time.
1962  */
1963 void ima_delete_rules(void)
1964 {
1965         struct ima_rule_entry *entry, *tmp;
1966
1967         temp_ima_appraise = 0;
1968         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1969                 list_del(&entry->list);
1970                 ima_free_rule(entry);
1971         }
1972 }
1973
1974 #define __ima_hook_stringify(func, str) (#func),
1975
1976 const char *const func_tokens[] = {
1977         __ima_hooks(__ima_hook_stringify)
1978 };
1979
1980 #ifdef  CONFIG_IMA_READ_POLICY
1981 enum {
1982         mask_exec = 0, mask_write, mask_read, mask_append
1983 };
1984
1985 static const char *const mask_tokens[] = {
1986         "^MAY_EXEC",
1987         "^MAY_WRITE",
1988         "^MAY_READ",
1989         "^MAY_APPEND"
1990 };
1991
1992 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1993 {
1994         loff_t l = *pos;
1995         struct ima_rule_entry *entry;
1996         struct list_head *ima_rules_tmp;
1997
1998         rcu_read_lock();
1999         ima_rules_tmp = rcu_dereference(ima_rules);
2000         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2001                 if (!l--) {
2002                         rcu_read_unlock();
2003                         return entry;
2004                 }
2005         }
2006         rcu_read_unlock();
2007         return NULL;
2008 }
2009
2010 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
2011 {
2012         struct ima_rule_entry *entry = v;
2013
2014         rcu_read_lock();
2015         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
2016         rcu_read_unlock();
2017         (*pos)++;
2018
2019         return (&entry->list == &ima_default_rules ||
2020                 &entry->list == &ima_policy_rules) ? NULL : entry;
2021 }
2022
2023 void ima_policy_stop(struct seq_file *m, void *v)
2024 {
2025 }
2026
2027 #define pt(token)       policy_tokens[token].pattern
2028 #define mt(token)       mask_tokens[token]
2029
2030 /*
2031  * policy_func_show - display the ima_hooks policy rule
2032  */
2033 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
2034 {
2035         if (func > 0 && func < MAX_CHECK)
2036                 seq_printf(m, "func=%s ", func_tokens[func]);
2037         else
2038                 seq_printf(m, "func=%d ", func);
2039 }
2040
2041 static void ima_show_rule_opt_list(struct seq_file *m,
2042                                    const struct ima_rule_opt_list *opt_list)
2043 {
2044         size_t i;
2045
2046         for (i = 0; i < opt_list->count; i++)
2047                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
2048 }
2049
2050 static void ima_policy_show_appraise_algos(struct seq_file *m,
2051                                            unsigned int allowed_hashes)
2052 {
2053         int idx, list_size = 0;
2054
2055         for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
2056                 if (!(allowed_hashes & (1U << idx)))
2057                         continue;
2058
2059                 /* only add commas if the list contains multiple entries */
2060                 if (list_size++)
2061                         seq_puts(m, ",");
2062
2063                 seq_puts(m, hash_algo_name[idx]);
2064         }
2065 }
2066
2067 int ima_policy_show(struct seq_file *m, void *v)
2068 {
2069         struct ima_rule_entry *entry = v;
2070         int i;
2071         char tbuf[64] = {0,};
2072         int offset = 0;
2073
2074         rcu_read_lock();
2075
2076         /* Do not print rules with inactive LSM labels */
2077         for (i = 0; i < MAX_LSM_RULES; i++) {
2078                 if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
2079                         rcu_read_unlock();
2080                         return 0;
2081                 }
2082         }
2083
2084         if (entry->action & MEASURE)
2085                 seq_puts(m, pt(Opt_measure));
2086         if (entry->action & DONT_MEASURE)
2087                 seq_puts(m, pt(Opt_dont_measure));
2088         if (entry->action & APPRAISE)
2089                 seq_puts(m, pt(Opt_appraise));
2090         if (entry->action & DONT_APPRAISE)
2091                 seq_puts(m, pt(Opt_dont_appraise));
2092         if (entry->action & AUDIT)
2093                 seq_puts(m, pt(Opt_audit));
2094         if (entry->action & HASH)
2095                 seq_puts(m, pt(Opt_hash));
2096         if (entry->action & DONT_HASH)
2097                 seq_puts(m, pt(Opt_dont_hash));
2098
2099         seq_puts(m, " ");
2100
2101         if (entry->flags & IMA_FUNC)
2102                 policy_func_show(m, entry->func);
2103
2104         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
2105                 if (entry->flags & IMA_MASK)
2106                         offset = 1;
2107                 if (entry->mask & MAY_EXEC)
2108                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2109                 if (entry->mask & MAY_WRITE)
2110                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2111                 if (entry->mask & MAY_READ)
2112                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2113                 if (entry->mask & MAY_APPEND)
2114                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2115                 seq_puts(m, " ");
2116         }
2117
2118         if (entry->flags & IMA_FSMAGIC) {
2119                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2120                 seq_printf(m, pt(Opt_fsmagic), tbuf);
2121                 seq_puts(m, " ");
2122         }
2123
2124         if (entry->flags & IMA_FSNAME) {
2125                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2126                 seq_printf(m, pt(Opt_fsname), tbuf);
2127                 seq_puts(m, " ");
2128         }
2129
2130         if (entry->flags & IMA_KEYRINGS) {
2131                 seq_puts(m, "keyrings=");
2132                 ima_show_rule_opt_list(m, entry->keyrings);
2133                 seq_puts(m, " ");
2134         }
2135
2136         if (entry->flags & IMA_LABEL) {
2137                 seq_puts(m, "label=");
2138                 ima_show_rule_opt_list(m, entry->label);
2139                 seq_puts(m, " ");
2140         }
2141
2142         if (entry->flags & IMA_PCR) {
2143                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2144                 seq_printf(m, pt(Opt_pcr), tbuf);
2145                 seq_puts(m, " ");
2146         }
2147
2148         if (entry->flags & IMA_FSUUID) {
2149                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2150                 seq_puts(m, " ");
2151         }
2152
2153         if (entry->flags & IMA_UID) {
2154                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2155                 if (entry->uid_op == &uid_gt)
2156                         seq_printf(m, pt(Opt_uid_gt), tbuf);
2157                 else if (entry->uid_op == &uid_lt)
2158                         seq_printf(m, pt(Opt_uid_lt), tbuf);
2159                 else
2160                         seq_printf(m, pt(Opt_uid_eq), tbuf);
2161                 seq_puts(m, " ");
2162         }
2163
2164         if (entry->flags & IMA_EUID) {
2165                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2166                 if (entry->uid_op == &uid_gt)
2167                         seq_printf(m, pt(Opt_euid_gt), tbuf);
2168                 else if (entry->uid_op == &uid_lt)
2169                         seq_printf(m, pt(Opt_euid_lt), tbuf);
2170                 else
2171                         seq_printf(m, pt(Opt_euid_eq), tbuf);
2172                 seq_puts(m, " ");
2173         }
2174
2175         if (entry->flags & IMA_GID) {
2176                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2177                 if (entry->gid_op == &gid_gt)
2178                         seq_printf(m, pt(Opt_gid_gt), tbuf);
2179                 else if (entry->gid_op == &gid_lt)
2180                         seq_printf(m, pt(Opt_gid_lt), tbuf);
2181                 else
2182                         seq_printf(m, pt(Opt_gid_eq), tbuf);
2183                 seq_puts(m, " ");
2184         }
2185
2186         if (entry->flags & IMA_EGID) {
2187                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2188                 if (entry->gid_op == &gid_gt)
2189                         seq_printf(m, pt(Opt_egid_gt), tbuf);
2190                 else if (entry->gid_op == &gid_lt)
2191                         seq_printf(m, pt(Opt_egid_lt), tbuf);
2192                 else
2193                         seq_printf(m, pt(Opt_egid_eq), tbuf);
2194                 seq_puts(m, " ");
2195         }
2196
2197         if (entry->flags & IMA_FOWNER) {
2198                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2199                 if (entry->fowner_op == &vfsuid_gt_kuid)
2200                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
2201                 else if (entry->fowner_op == &vfsuid_lt_kuid)
2202                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
2203                 else
2204                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
2205                 seq_puts(m, " ");
2206         }
2207
2208         if (entry->flags & IMA_FGROUP) {
2209                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2210                 if (entry->fgroup_op == &vfsgid_gt_kgid)
2211                         seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2212                 else if (entry->fgroup_op == &vfsgid_lt_kgid)
2213                         seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2214                 else
2215                         seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2216                 seq_puts(m, " ");
2217         }
2218
2219         if (entry->flags & IMA_VALIDATE_ALGOS) {
2220                 seq_puts(m, "appraise_algos=");
2221                 ima_policy_show_appraise_algos(m, entry->allowed_algos);
2222                 seq_puts(m, " ");
2223         }
2224
2225         for (i = 0; i < MAX_LSM_RULES; i++) {
2226                 if (entry->lsm[i].rule) {
2227                         switch (i) {
2228                         case LSM_OBJ_USER:
2229                                 seq_printf(m, pt(Opt_obj_user),
2230                                            entry->lsm[i].args_p);
2231                                 break;
2232                         case LSM_OBJ_ROLE:
2233                                 seq_printf(m, pt(Opt_obj_role),
2234                                            entry->lsm[i].args_p);
2235                                 break;
2236                         case LSM_OBJ_TYPE:
2237                                 seq_printf(m, pt(Opt_obj_type),
2238                                            entry->lsm[i].args_p);
2239                                 break;
2240                         case LSM_SUBJ_USER:
2241                                 seq_printf(m, pt(Opt_subj_user),
2242                                            entry->lsm[i].args_p);
2243                                 break;
2244                         case LSM_SUBJ_ROLE:
2245                                 seq_printf(m, pt(Opt_subj_role),
2246                                            entry->lsm[i].args_p);
2247                                 break;
2248                         case LSM_SUBJ_TYPE:
2249                                 seq_printf(m, pt(Opt_subj_type),
2250                                            entry->lsm[i].args_p);
2251                                 break;
2252                         }
2253                         seq_puts(m, " ");
2254                 }
2255         }
2256         if (entry->template)
2257                 seq_printf(m, "template=%s ", entry->template->name);
2258         if (entry->flags & IMA_DIGSIG_REQUIRED) {
2259                 if (entry->flags & IMA_VERITY_REQUIRED)
2260                         seq_puts(m, "appraise_type=sigv3 ");
2261                 else if (entry->flags & IMA_MODSIG_ALLOWED)
2262                         seq_puts(m, "appraise_type=imasig|modsig ");
2263                 else
2264                         seq_puts(m, "appraise_type=imasig ");
2265         }
2266         if (entry->flags & IMA_VERITY_REQUIRED)
2267                 seq_puts(m, "digest_type=verity ");
2268         if (entry->flags & IMA_CHECK_BLACKLIST)
2269                 seq_puts(m, "appraise_flag=check_blacklist ");
2270         if (entry->flags & IMA_PERMIT_DIRECTIO)
2271                 seq_puts(m, "permit_directio ");
2272         rcu_read_unlock();
2273         seq_puts(m, "\n");
2274         return 0;
2275 }
2276 #endif  /* CONFIG_IMA_READ_POLICY */
2277
2278 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2279 /*
2280  * ima_appraise_signature: whether IMA will appraise a given function using
2281  * an IMA digital signature. This is restricted to cases where the kernel
2282  * has a set of built-in trusted keys in order to avoid an attacker simply
2283  * loading additional keys.
2284  */
2285 bool ima_appraise_signature(enum kernel_read_file_id id)
2286 {
2287         struct ima_rule_entry *entry;
2288         bool found = false;
2289         enum ima_hooks func;
2290         struct list_head *ima_rules_tmp;
2291
2292         if (id >= READING_MAX_ID)
2293                 return false;
2294
2295         if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2296             && security_locked_down(LOCKDOWN_KEXEC))
2297                 return false;
2298
2299         func = read_idmap[id] ?: FILE_CHECK;
2300
2301         rcu_read_lock();
2302         ima_rules_tmp = rcu_dereference(ima_rules);
2303         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2304                 if (entry->action != APPRAISE)
2305                         continue;
2306
2307                 /*
2308                  * A generic entry will match, but otherwise require that it
2309                  * match the func we're looking for
2310                  */
2311                 if (entry->func && entry->func != func)
2312                         continue;
2313
2314                 /*
2315                  * We require this to be a digital signature, not a raw IMA
2316                  * hash.
2317                  */
2318                 if (entry->flags & IMA_DIGSIG_REQUIRED)
2319                         found = true;
2320
2321                 /*
2322                  * We've found a rule that matches, so break now even if it
2323                  * didn't require a digital signature - a later rule that does
2324                  * won't override it, so would be a false positive.
2325                  */
2326                 break;
2327         }
2328
2329         rcu_read_unlock();
2330         return found;
2331 }
2332 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */