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 <[email protected]>
   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 ima_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[] __counted_by(count);
  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         opt_list->count = count;
 346
 347         /*
 348          * strsep() has already replaced all instances of '|' with '\0',
 349          * leaving a byte sequence of NUL-terminated strings. Reference each
 350          * string with the array of items.
 351          *
 352          * IMPORTANT: Ownership of the allocated buffer is transferred from
 353          * src_copy to the first element in the items array. To free the
 354          * buffer, kfree() must only be called on the first element of the
 355          * array.
 356          */
 357         for (i = 0, cur = src_copy; i < count; i++) {
 358                 opt_list->items[i] = cur;
 359                 cur = strchr(cur, '\0') + 1;
 360         }
 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                                                 gfp_t gfp)
 406 {
 407         struct ima_rule_entry *nentry;
 408         int i;
 409
 410         /*
 411          * Immutable elements are copied over as pointers and data; only
 412          * lsm rules can change
 413          */
 414         nentry = kmemdup(entry, sizeof(*nentry), gfp);
 415         if (!nentry)
 416                 return NULL;
 417
 418         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 419
 420         for (i = 0; i < MAX_LSM_RULES; i++) {
 421                 if (!entry->lsm[i].args_p)
 422                         continue;
 423
 424                 nentry->lsm[i].type = entry->lsm[i].type;
 425                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 426
 427                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 428                                      nentry->lsm[i].args_p,
 429                                      &nentry->lsm[i].rule,
 430                                      gfp);
 431                 if (!nentry->lsm[i].rule)
 432                         pr_warn("rule for LSM \'%s\' is undefined\n",
 433                                 nentry->lsm[i].args_p);
 434         }
 435         return nentry;
 436 }
 437
 438 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 439 {
 440         int i;
 441         struct ima_rule_entry *nentry;
 442
 443         nentry = ima_lsm_copy_rule(entry, GFP_KERNEL);
 444         if (!nentry)
 445                 return -ENOMEM;
 446
 447         list_replace_rcu(&entry->list, &nentry->list);
 448         synchronize_rcu();
 449         /*
 450          * ima_lsm_copy_rule() shallow copied all references, except for the
 451          * LSM references, from entry to nentry so we only want to free the LSM
 452          * references and the entry itself. All other memory references will now
 453          * be owned by nentry.
 454          */
 455         for (i = 0; i < MAX_LSM_RULES; i++)
 456                 ima_filter_rule_free(entry->lsm[i].rule);
 457         kfree(entry);
 458
 459         return 0;
 460 }
 461
 462 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 463 {
 464         int i;
 465
 466         for (i = 0; i < MAX_LSM_RULES; i++)
 467                 if (entry->lsm[i].args_p)
 468                         return true;
 469
 470         return false;
 471 }
 472
 473 /*
 474  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 475  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 476  * the reloaded LSM policy.
 477  */
 478 static void ima_lsm_update_rules(void)
 479 {
 480         struct ima_rule_entry *entry, *e;
 481         int result;
 482
 483         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 484                 if (!ima_rule_contains_lsm_cond(entry))
 485                         continue;
 486
 487                 result = ima_lsm_update_rule(entry);
 488                 if (result) {
 489                         pr_err("lsm rule update error %d\n", result);
 490                         return;
 491                 }
 492         }
 493 }
 494
 495 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 496                           void *lsm_data)
 497 {
 498         if (event != LSM_POLICY_CHANGE)
 499                 return NOTIFY_DONE;
 500
 501         ima_lsm_update_rules();
 502         return NOTIFY_OK;
 503 }
 504
 505 /**
 506  * ima_match_rule_data - determine whether func_data matches the policy rule
 507  * @rule: a pointer to a rule
 508  * @func_data: data to match against the measure rule data
 509  * @cred: a pointer to a credentials structure for user validation
 510  *
 511  * Returns true if func_data matches one in the rule, false otherwise.
 512  */
 513 static bool ima_match_rule_data(struct ima_rule_entry *rule,
 514                                 const char *func_data,
 515                                 const struct cred *cred)
 516 {
 517         const struct ima_rule_opt_list *opt_list = NULL;
 518         bool matched = false;
 519         size_t i;
 520
 521         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 522                 return false;
 523
 524         switch (rule->func) {
 525         case KEY_CHECK:
 526                 if (!rule->keyrings)
 527                         return true;
 528
 529                 opt_list = rule->keyrings;
 530                 break;
 531         case CRITICAL_DATA:
 532                 if (!rule->label)
 533                         return true;
 534
 535                 opt_list = rule->label;
 536                 break;
 537         default:
 538                 return false;
 539         }
 540
 541         if (!func_data)
 542                 return false;
 543
 544         for (i = 0; i < opt_list->count; i++) {
 545                 if (!strcmp(opt_list->items[i], func_data)) {
 546                         matched = true;
 547                         break;
 548                 }
 549         }
 550
 551         return matched;
 552 }
 553
 554 /**
 555  * ima_match_rules - determine whether an inode matches the policy rule.
 556  * @rule: a pointer to a rule
 557  * @idmap: idmap of the mount the inode was found from
 558  * @inode: a pointer to an inode
 559  * @cred: a pointer to a credentials structure for user validation
 560  * @prop: LSM properties of the task to be validated
 561  * @func: LIM hook identifier
 562  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 563  * @func_data: func specific data, may be NULL
 564  *
 565  * Returns true on rule match, false on failure.
 566  */
 567 static bool ima_match_rules(struct ima_rule_entry *rule,
 568                             struct mnt_idmap *idmap,
 569                             struct inode *inode, const struct cred *cred,
 570                             struct lsm_prop *prop, enum ima_hooks func, int mask,
 571                             const char *func_data)
 572 {
 573         int i;
 574         bool result = false;
 575         struct ima_rule_entry *lsm_rule = rule;
 576         bool rule_reinitialized = false;
 577
 578         if ((rule->flags & IMA_FUNC) &&
 579             (rule->func != func && func != POST_SETATTR))
 580                 return false;
 581
 582         switch (func) {
 583         case KEY_CHECK:
 584         case CRITICAL_DATA:
 585                 return ((rule->func == func) &&
 586                         ima_match_rule_data(rule, func_data, cred));
 587         default:
 588                 break;
 589         }
 590
 591         if ((rule->flags & IMA_MASK) &&
 592             (rule->mask != mask && func != POST_SETATTR))
 593                 return false;
 594         if ((rule->flags & IMA_INMASK) &&
 595             (!(rule->mask & mask) && func != POST_SETATTR))
 596                 return false;
 597         if ((rule->flags & IMA_FSMAGIC)
 598             && rule->fsmagic != inode->i_sb->s_magic)
 599                 return false;
 600         if ((rule->flags & IMA_FSNAME)
 601             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 602                 return false;
 603         if ((rule->flags & IMA_FSUUID) &&
 604             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 605                 return false;
 606         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 607                 return false;
 608         if (rule->flags & IMA_EUID) {
 609                 if (has_capability_noaudit(current, CAP_SETUID)) {
 610                         if (!rule->uid_op(cred->euid, rule->uid)
 611                             && !rule->uid_op(cred->suid, rule->uid)
 612                             && !rule->uid_op(cred->uid, rule->uid))
 613                                 return false;
 614                 } else if (!rule->uid_op(cred->euid, rule->uid))
 615                         return false;
 616         }
 617         if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
 618                 return false;
 619         if (rule->flags & IMA_EGID) {
 620                 if (has_capability_noaudit(current, CAP_SETGID)) {
 621                         if (!rule->gid_op(cred->egid, rule->gid)
 622                             && !rule->gid_op(cred->sgid, rule->gid)
 623                             && !rule->gid_op(cred->gid, rule->gid))
 624                                 return false;
 625                 } else if (!rule->gid_op(cred->egid, rule->gid))
 626                         return false;
 627         }
 628         if ((rule->flags & IMA_FOWNER) &&
 629             !rule->fowner_op(i_uid_into_vfsuid(idmap, inode),
 630                              rule->fowner))
 631                 return false;
 632         if ((rule->flags & IMA_FGROUP) &&
 633             !rule->fgroup_op(i_gid_into_vfsgid(idmap, inode),
 634                              rule->fgroup))
 635                 return false;
 636         for (i = 0; i < MAX_LSM_RULES; i++) {
 637                 int rc = 0;
 638                 struct lsm_prop inode_prop = { };
 639
 640                 if (!lsm_rule->lsm[i].rule) {
 641                         if (!lsm_rule->lsm[i].args_p)
 642                                 continue;
 643                         else
 644                                 return false;
 645                 }
 646
 647 retry:
 648                 switch (i) {
 649                 case LSM_OBJ_USER:
 650                 case LSM_OBJ_ROLE:
 651                 case LSM_OBJ_TYPE:
 652                         security_inode_getlsmprop(inode, &inode_prop);
 653                         rc = ima_filter_rule_match(&inode_prop,
 654                                                    lsm_rule->lsm[i].type,
 655                                                    Audit_equal,
 656                                                    lsm_rule->lsm[i].rule);
 657                         break;
 658                 case LSM_SUBJ_USER:
 659                 case LSM_SUBJ_ROLE:
 660                 case LSM_SUBJ_TYPE:
 661                         rc = ima_filter_rule_match(prop, lsm_rule->lsm[i].type,
 662                                                    Audit_equal,
 663                                                    lsm_rule->lsm[i].rule);
 664                         break;
 665                 default:
 666                         break;
 667                 }
 668
 669                 if (rc == -ESTALE && !rule_reinitialized) {
 670                         lsm_rule = ima_lsm_copy_rule(rule, GFP_ATOMIC);
 671                         if (lsm_rule) {
 672                                 rule_reinitialized = true;
 673                                 goto retry;
 674                         }
 675                 }
 676                 if (!rc) {
 677                         result = false;
 678                         goto out;
 679                 }
 680         }
 681         result = true;
 682
 683 out:
 684         if (rule_reinitialized) {
 685                 for (i = 0; i < MAX_LSM_RULES; i++)
 686                         ima_filter_rule_free(lsm_rule->lsm[i].rule);
 687                 kfree(lsm_rule);
 688         }
 689         return result;
 690 }
 691
 692 /*
 693  * In addition to knowing that we need to appraise the file in general,
 694  * we need to differentiate between calling hooks, for hook specific rules.
 695  */
 696 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 697 {
 698         if (!(rule->flags & IMA_FUNC))
 699                 return IMA_FILE_APPRAISE;
 700
 701         switch (func) {
 702         case MMAP_CHECK:
 703         case MMAP_CHECK_REQPROT:
 704                 return IMA_MMAP_APPRAISE;
 705         case BPRM_CHECK:
 706                 return IMA_BPRM_APPRAISE;
 707         case CREDS_CHECK:
 708                 return IMA_CREDS_APPRAISE;
 709         case FILE_CHECK:
 710         case POST_SETATTR:
 711                 return IMA_FILE_APPRAISE;
 712         case MODULE_CHECK ... MAX_CHECK - 1:
 713         default:
 714                 return IMA_READ_APPRAISE;
 715         }
 716 }
 717
 718 /**
 719  * ima_match_policy - decision based on LSM and other conditions
 720  * @idmap: idmap of the mount the inode was found from
 721  * @inode: pointer to an inode for which the policy decision is being made
 722  * @cred: pointer to a credentials structure for which the policy decision is
 723  *        being made
 724  * @prop: LSM properties of the task to be validated
 725  * @func: IMA hook identifier
 726  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 727  * @flags: IMA actions to consider (e.g. IMA_MEASURE | IMA_APPRAISE)
 728  * @pcr: set the pcr to extend
 729  * @template_desc: the template that should be used for this rule
 730  * @func_data: func specific data, may be NULL
 731  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
 732  *
 733  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 734  * conditions.
 735  *
 736  * Since the IMA policy may be updated multiple times we need to lock the
 737  * list when walking it.  Reads are many orders of magnitude more numerous
 738  * than writes so ima_match_policy() is classical RCU candidate.
 739  */
 740 int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
 741                      const struct cred *cred, struct lsm_prop *prop,
 742                      enum ima_hooks func, int mask, int flags, int *pcr,
 743                      struct ima_template_desc **template_desc,
 744                      const char *func_data, unsigned int *allowed_algos)
 745 {
 746         struct ima_rule_entry *entry;
 747         int action = 0, actmask = flags | (flags << 1);
 748         struct list_head *ima_rules_tmp;
 749
 750         if (template_desc && !*template_desc)
 751                 *template_desc = ima_template_desc_current();
 752
 753         rcu_read_lock();
 754         ima_rules_tmp = rcu_dereference(ima_rules);
 755         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 756
 757                 if (!(entry->action & actmask))
 758                         continue;
 759
 760                 if (!ima_match_rules(entry, idmap, inode, cred, prop,
 761                                      func, mask, func_data))
 762                         continue;
 763
 764                 action |= entry->flags & IMA_NONACTION_FLAGS;
 765
 766                 action |= entry->action & IMA_DO_MASK;
 767                 if (entry->action & IMA_APPRAISE) {
 768                         action |= get_subaction(entry, func);
 769                         action &= ~IMA_HASH;
 770                         if (ima_fail_unverifiable_sigs)
 771                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 772
 773                         if (allowed_algos &&
 774                             entry->flags & IMA_VALIDATE_ALGOS)
 775                                 *allowed_algos = entry->allowed_algos;
 776                 }
 777
 778                 if (entry->action & IMA_DO_MASK)
 779                         actmask &= ~(entry->action | entry->action << 1);
 780                 else
 781                         actmask &= ~(entry->action | entry->action >> 1);
 782
 783                 if ((pcr) && (entry->flags & IMA_PCR))
 784                         *pcr = entry->pcr;
 785
 786                 if (template_desc && entry->template)
 787                         *template_desc = entry->template;
 788
 789                 if (!actmask)
 790                         break;
 791         }
 792         rcu_read_unlock();
 793
 794         return action;
 795 }
 796
 797 /**
 798  * ima_update_policy_flags() - Update global IMA variables
 799  *
 800  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
 801  * based on the currently loaded policy.
 802  *
 803  * With ima_policy_flag, the decision to short circuit out of a function
 804  * or not call the function in the first place can be made earlier.
 805  *
 806  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
 807  * set of hash algorithms accepted when updating the security.ima xattr of
 808  * a file.
 809  *
 810  * Context: called after a policy update and at system initialization.
 811  */
 812 void ima_update_policy_flags(void)
 813 {
 814         struct ima_rule_entry *entry;
 815         int new_policy_flag = 0;
 816         struct list_head *ima_rules_tmp;
 817
 818         rcu_read_lock();
 819         ima_rules_tmp = rcu_dereference(ima_rules);
 820         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 821                 /*
 822                  * SETXATTR_CHECK rules do not implement a full policy check
 823                  * because rule checking would probably have an important
 824                  * performance impact on setxattr(). As a consequence, only one
 825                  * SETXATTR_CHECK can be active at a given time.
 826                  * Because we want to preserve that property, we set out to use
 827                  * atomic_cmpxchg. Either:
 828                  * - the atomic was non-zero: a setxattr hash policy is
 829                  *   already enforced, we do nothing
 830                  * - the atomic was zero: no setxattr policy was set, enable
 831                  *   the setxattr hash policy
 832                  */
 833                 if (entry->func == SETXATTR_CHECK) {
 834                         atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
 835                                        0, entry->allowed_algos);
 836                         /* SETXATTR_CHECK doesn't impact ima_policy_flag */
 837                         continue;
 838                 }
 839
 840                 if (entry->action & IMA_DO_MASK)
 841                         new_policy_flag |= entry->action;
 842         }
 843         rcu_read_unlock();
 844
 845         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 846         if (!ima_appraise)
 847                 new_policy_flag &= ~IMA_APPRAISE;
 848
 849         ima_policy_flag = new_policy_flag;
 850 }
 851
 852 static int ima_appraise_flag(enum ima_hooks func)
 853 {
 854         if (func == MODULE_CHECK)
 855                 return IMA_APPRAISE_MODULES;
 856         else if (func == FIRMWARE_CHECK)
 857                 return IMA_APPRAISE_FIRMWARE;
 858         else if (func == POLICY_CHECK)
 859                 return IMA_APPRAISE_POLICY;
 860         else if (func == KEXEC_KERNEL_CHECK)
 861                 return IMA_APPRAISE_KEXEC;
 862         return 0;
 863 }
 864
 865 static void add_rules(struct ima_rule_entry *entries, int count,
 866                       enum policy_rule_list policy_rule)
 867 {
 868         int i = 0;
 869
 870         for (i = 0; i < count; i++) {
 871                 struct ima_rule_entry *entry;
 872
 873                 if (policy_rule & IMA_DEFAULT_POLICY)
 874                         list_add_tail(&entries[i].list, &ima_default_rules);
 875
 876                 if (policy_rule & IMA_CUSTOM_POLICY) {
 877                         entry = kmemdup(&entries[i], sizeof(*entry),
 878                                         GFP_KERNEL);
 879                         if (!entry)
 880                                 continue;
 881
 882                         list_add_tail(&entry->list, &ima_policy_rules);
 883                 }
 884                 if (entries[i].action == APPRAISE) {
 885                         if (entries != build_appraise_rules)
 886                                 temp_ima_appraise |=
 887                                         ima_appraise_flag(entries[i].func);
 888                         else
 889                                 build_ima_appraise |=
 890                                         ima_appraise_flag(entries[i].func);
 891                 }
 892         }
 893 }
 894
 895 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 896
 897 static int __init ima_init_arch_policy(void)
 898 {
 899         const char * const *arch_rules;
 900         const char * const *rules;
 901         int arch_entries = 0;
 902         int i = 0;
 903
 904         arch_rules = arch_get_ima_policy();
 905         if (!arch_rules)
 906                 return arch_entries;
 907
 908         /* Get number of rules */
 909         for (rules = arch_rules; *rules != NULL; rules++)
 910                 arch_entries++;
 911
 912         arch_policy_entry = kcalloc(arch_entries + 1,
 913                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 914         if (!arch_policy_entry)
 915                 return 0;
 916
 917         /* Convert each policy string rules to struct ima_rule_entry format */
 918         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 919                 char rule[255];
 920                 int result;
 921
 922                 result = strscpy(rule, *rules, sizeof(rule));
 923
 924                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 925                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 926                 if (result) {
 927                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 928                                 rule);
 929                         memset(&arch_policy_entry[i], 0,
 930                                sizeof(*arch_policy_entry));
 931                         continue;
 932                 }
 933                 i++;
 934         }
 935         return i;
 936 }
 937
 938 /**
 939  * ima_init_policy - initialize the default measure rules.
 940  *
 941  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
 942  */
 943 void __init ima_init_policy(void)
 944 {
 945         int build_appraise_entries, arch_entries;
 946
 947         /* if !ima_policy, we load NO default rules */
 948         if (ima_policy)
 949                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 950                           IMA_DEFAULT_POLICY);
 951
 952         switch (ima_policy) {
 953         case ORIGINAL_TCB:
 954                 add_rules(original_measurement_rules,
 955                           ARRAY_SIZE(original_measurement_rules),
 956                           IMA_DEFAULT_POLICY);
 957                 break;
 958         case DEFAULT_TCB:
 959                 add_rules(default_measurement_rules,
 960                           ARRAY_SIZE(default_measurement_rules),
 961                           IMA_DEFAULT_POLICY);
 962                 break;
 963         default:
 964                 break;
 965         }
 966
 967         /*
 968          * Based on runtime secure boot flags, insert arch specific measurement
 969          * and appraise rules requiring file signatures for both the initial
 970          * and custom policies, prior to other appraise rules.
 971          * (Highest priority)
 972          */
 973         arch_entries = ima_init_arch_policy();
 974         if (!arch_entries)
 975                 pr_info("No architecture policies found\n");
 976         else
 977                 add_rules(arch_policy_entry, arch_entries,
 978                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 979
 980         /*
 981          * Insert the builtin "secure_boot" policy rules requiring file
 982          * signatures, prior to other appraise rules.
 983          */
 984         if (ima_use_secure_boot)
 985                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 986                           IMA_DEFAULT_POLICY);
 987
 988         /*
 989          * Insert the build time appraise rules requiring file signatures
 990          * for both the initial and custom policies, prior to other appraise
 991          * rules. As the secure boot rules includes all of the build time
 992          * rules, include either one or the other set of rules, but not both.
 993          */
 994         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 995         if (build_appraise_entries) {
 996                 if (ima_use_secure_boot)
 997                         add_rules(build_appraise_rules, build_appraise_entries,
 998                                   IMA_CUSTOM_POLICY);
 999                 else
1000                         add_rules(build_appraise_rules, build_appraise_entries,
1001                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
1002         }
1003
1004         if (ima_use_appraise_tcb)
1005                 add_rules(default_appraise_rules,
1006                           ARRAY_SIZE(default_appraise_rules),
1007                           IMA_DEFAULT_POLICY);
1008
1009         if (ima_use_critical_data)
1010                 add_rules(critical_data_rules,
1011                           ARRAY_SIZE(critical_data_rules),
1012                           IMA_DEFAULT_POLICY);
1013
1014         atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
1015
1016         ima_update_policy_flags();
1017 }
1018
1019 /* Make sure we have a valid policy, at least containing some rules. */
1020 int ima_check_policy(void)
1021 {
1022         if (list_empty(&ima_temp_rules))
1023                 return -EINVAL;
1024         return 0;
1025 }
1026
1027 /**
1028  * ima_update_policy - update default_rules with new measure rules
1029  *
1030  * Called on file .release to update the default rules with a complete new
1031  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
1032  * they make a queue.  The policy may be updated multiple times and this is the
1033  * RCU updater.
1034  *
1035  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
1036  * we switch from the default policy to user defined.
1037  */
1038 void ima_update_policy(void)
1039 {
1040         struct list_head *policy = &ima_policy_rules;
1041
1042         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
1043
1044         if (ima_rules != (struct list_head __rcu *)policy) {
1045                 ima_policy_flag = 0;
1046
1047                 rcu_assign_pointer(ima_rules, policy);
1048                 /*
1049                  * IMA architecture specific policy rules are specified
1050                  * as strings and converted to an array of ima_entry_rules
1051                  * on boot.  After loading a custom policy, free the
1052                  * architecture specific rules stored as an array.
1053                  */
1054                 kfree(arch_policy_entry);
1055         }
1056         ima_update_policy_flags();
1057
1058         /* Custom IMA policy has been loaded */
1059         ima_process_queued_keys();
1060 }
1061
1062 /* Keep the enumeration in sync with the policy_tokens! */
1063 enum policy_opt {
1064         Opt_measure, Opt_dont_measure,
1065         Opt_appraise, Opt_dont_appraise,
1066         Opt_audit, Opt_hash, Opt_dont_hash,
1067         Opt_obj_user, Opt_obj_role, Opt_obj_type,
1068         Opt_subj_user, Opt_subj_role, Opt_subj_type,
1069         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1070         Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1071         Opt_fowner_eq, Opt_fgroup_eq,
1072         Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1073         Opt_fowner_gt, Opt_fgroup_gt,
1074         Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1075         Opt_fowner_lt, Opt_fgroup_lt,
1076         Opt_digest_type,
1077         Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1078         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1079         Opt_label, Opt_err
1080 };
1081
1082 static const match_table_t policy_tokens = {
1083         {Opt_measure, "measure"},
1084         {Opt_dont_measure, "dont_measure"},
1085         {Opt_appraise, "appraise"},
1086         {Opt_dont_appraise, "dont_appraise"},
1087         {Opt_audit, "audit"},
1088         {Opt_hash, "hash"},
1089         {Opt_dont_hash, "dont_hash"},
1090         {Opt_obj_user, "obj_user=%s"},
1091         {Opt_obj_role, "obj_role=%s"},
1092         {Opt_obj_type, "obj_type=%s"},
1093         {Opt_subj_user, "subj_user=%s"},
1094         {Opt_subj_role, "subj_role=%s"},
1095         {Opt_subj_type, "subj_type=%s"},
1096         {Opt_func, "func=%s"},
1097         {Opt_mask, "mask=%s"},
1098         {Opt_fsmagic, "fsmagic=%s"},
1099         {Opt_fsname, "fsname=%s"},
1100         {Opt_fsuuid, "fsuuid=%s"},
1101         {Opt_uid_eq, "uid=%s"},
1102         {Opt_euid_eq, "euid=%s"},
1103         {Opt_gid_eq, "gid=%s"},
1104         {Opt_egid_eq, "egid=%s"},
1105         {Opt_fowner_eq, "fowner=%s"},
1106         {Opt_fgroup_eq, "fgroup=%s"},
1107         {Opt_uid_gt, "uid>%s"},
1108         {Opt_euid_gt, "euid>%s"},
1109         {Opt_gid_gt, "gid>%s"},
1110         {Opt_egid_gt, "egid>%s"},
1111         {Opt_fowner_gt, "fowner>%s"},
1112         {Opt_fgroup_gt, "fgroup>%s"},
1113         {Opt_uid_lt, "uid<%s"},
1114         {Opt_euid_lt, "euid<%s"},
1115         {Opt_gid_lt, "gid<%s"},
1116         {Opt_egid_lt, "egid<%s"},
1117         {Opt_fowner_lt, "fowner<%s"},
1118         {Opt_fgroup_lt, "fgroup<%s"},
1119         {Opt_digest_type, "digest_type=%s"},
1120         {Opt_appraise_type, "appraise_type=%s"},
1121         {Opt_appraise_flag, "appraise_flag=%s"},
1122         {Opt_appraise_algos, "appraise_algos=%s"},
1123         {Opt_permit_directio, "permit_directio"},
1124         {Opt_pcr, "pcr=%s"},
1125         {Opt_template, "template=%s"},
1126         {Opt_keyrings, "keyrings=%s"},
1127         {Opt_label, "label=%s"},
1128         {Opt_err, NULL}
1129 };
1130
1131 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1132                              substring_t *args, int lsm_rule, int audit_type)
1133 {
1134         int result;
1135
1136         if (entry->lsm[lsm_rule].rule)
1137                 return -EINVAL;
1138
1139         entry->lsm[lsm_rule].args_p = match_strdup(args);
1140         if (!entry->lsm[lsm_rule].args_p)
1141                 return -ENOMEM;
1142
1143         entry->lsm[lsm_rule].type = audit_type;
1144         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1145                                       entry->lsm[lsm_rule].args_p,
1146                                       &entry->lsm[lsm_rule].rule,
1147                                       GFP_KERNEL);
1148         if (!entry->lsm[lsm_rule].rule) {
1149                 pr_warn("rule for LSM \'%s\' is undefined\n",
1150                         entry->lsm[lsm_rule].args_p);
1151
1152                 if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1153                         kfree(entry->lsm[lsm_rule].args_p);
1154                         entry->lsm[lsm_rule].args_p = NULL;
1155                         result = -EINVAL;
1156                 } else
1157                         result = 0;
1158         }
1159
1160         return result;
1161 }
1162
1163 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1164                               enum policy_opt rule_operator)
1165 {
1166         if (!ab)
1167                 return;
1168
1169         switch (rule_operator) {
1170         case Opt_uid_gt:
1171         case Opt_euid_gt:
1172         case Opt_gid_gt:
1173         case Opt_egid_gt:
1174         case Opt_fowner_gt:
1175         case Opt_fgroup_gt:
1176                 audit_log_format(ab, "%s>", key);
1177                 break;
1178         case Opt_uid_lt:
1179         case Opt_euid_lt:
1180         case Opt_gid_lt:
1181         case Opt_egid_lt:
1182         case Opt_fowner_lt:
1183         case Opt_fgroup_lt:
1184                 audit_log_format(ab, "%s<", key);
1185                 break;
1186         default:
1187                 audit_log_format(ab, "%s=", key);
1188         }
1189         audit_log_format(ab, "%s ", value);
1190 }
1191 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1192 {
1193         ima_log_string_op(ab, key, value, Opt_err);
1194 }
1195
1196 /*
1197  * Validating the appended signature included in the measurement list requires
1198  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1199  * field). Therefore, notify the user if they have the 'modsig' field but not
1200  * the 'd-modsig' field in the template.
1201  */
1202 static void check_template_modsig(const struct ima_template_desc *template)
1203 {
1204 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1205         bool has_modsig, has_dmodsig;
1206         static bool checked;
1207         int i;
1208
1209         /* We only need to notify the user once. */
1210         if (checked)
1211                 return;
1212
1213         has_modsig = has_dmodsig = false;
1214         for (i = 0; i < template->num_fields; i++) {
1215                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1216                         has_modsig = true;
1217                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1218                         has_dmodsig = true;
1219         }
1220
1221         if (has_modsig && !has_dmodsig)
1222                 pr_notice(MSG);
1223
1224         checked = true;
1225 #undef MSG
1226 }
1227
1228 /*
1229  * Warn if the template does not contain the given field.
1230  */
1231 static void check_template_field(const struct ima_template_desc *template,
1232                                  const char *field, const char *msg)
1233 {
1234         int i;
1235
1236         for (i = 0; i < template->num_fields; i++)
1237                 if (!strcmp(template->fields[i]->field_id, field))
1238                         return;
1239
1240         pr_notice_once("%s", msg);
1241 }
1242
1243 static bool ima_validate_rule(struct ima_rule_entry *entry)
1244 {
1245         /* Ensure that the action is set and is compatible with the flags */
1246         if (entry->action == UNKNOWN)
1247                 return false;
1248
1249         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1250                 return false;
1251
1252         if (entry->action != APPRAISE &&
1253             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1254                             IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1255                 return false;
1256
1257         /*
1258          * The IMA_FUNC bit must be set if and only if there's a valid hook
1259          * function specified, and vice versa. Enforcing this property allows
1260          * for the NONE case below to validate a rule without an explicit hook
1261          * function.
1262          */
1263         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1264             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1265                 return false;
1266
1267         /*
1268          * Ensure that the hook function is compatible with the other
1269          * components of the rule
1270          */
1271         switch (entry->func) {
1272         case NONE:
1273         case FILE_CHECK:
1274         case MMAP_CHECK:
1275         case MMAP_CHECK_REQPROT:
1276         case BPRM_CHECK:
1277         case CREDS_CHECK:
1278         case POST_SETATTR:
1279         case FIRMWARE_CHECK:
1280         case POLICY_CHECK:
1281                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1282                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1283                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1284                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1285                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1286                                      IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1287                                      IMA_CHECK_BLACKLIST | IMA_VERITY_REQUIRED))
1288                         return false;
1289
1290                 break;
1291         case MODULE_CHECK:
1292         case KEXEC_KERNEL_CHECK:
1293         case KEXEC_INITRAMFS_CHECK:
1294                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1295                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1296                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1297                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1298                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1299                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1300                                      IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1301                         return false;
1302
1303                 break;
1304         case KEXEC_CMDLINE:
1305                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1306                         return false;
1307
1308                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1309                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1310                                      IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1311                                      IMA_FGROUP))
1312                         return false;
1313
1314                 break;
1315         case KEY_CHECK:
1316                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1317                         return false;
1318
1319                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1320                                      IMA_KEYRINGS))
1321                         return false;
1322
1323                 if (ima_rule_contains_lsm_cond(entry))
1324                         return false;
1325
1326                 break;
1327         case CRITICAL_DATA:
1328                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1329                         return false;
1330
1331                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1332                                      IMA_LABEL))
1333                         return false;
1334
1335                 if (ima_rule_contains_lsm_cond(entry))
1336                         return false;
1337
1338                 break;
1339         case SETXATTR_CHECK:
1340                 /* any action other than APPRAISE is unsupported */
1341                 if (entry->action != APPRAISE)
1342                         return false;
1343
1344                 /* SETXATTR_CHECK requires an appraise_algos parameter */
1345                 if (!(entry->flags & IMA_VALIDATE_ALGOS))
1346                         return false;
1347
1348                 /*
1349                  * full policies are not supported, they would have too
1350                  * much of a performance impact
1351                  */
1352                 if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1353                         return false;
1354
1355                 break;
1356         default:
1357                 return false;
1358         }
1359
1360         /* Ensure that combinations of flags are compatible with each other */
1361         if (entry->flags & IMA_CHECK_BLACKLIST &&
1362             !(entry->flags & IMA_DIGSIG_REQUIRED))
1363                 return false;
1364
1365         /*
1366          * Unlike for regular IMA 'appraise' policy rules where security.ima
1367          * xattr may contain either a file hash or signature, the security.ima
1368          * xattr for fsverity must contain a file signature (sigv3).  Ensure
1369          * that 'appraise' rules for fsverity require file signatures by
1370          * checking the IMA_DIGSIG_REQUIRED flag is set.
1371          */
1372         if (entry->action == APPRAISE &&
1373             (entry->flags & IMA_VERITY_REQUIRED) &&
1374             !(entry->flags & IMA_DIGSIG_REQUIRED))
1375                 return false;
1376
1377         return true;
1378 }
1379
1380 static unsigned int ima_parse_appraise_algos(char *arg)
1381 {
1382         unsigned int res = 0;
1383         int idx;
1384         char *token;
1385
1386         while ((token = strsep(&arg, ",")) != NULL) {
1387                 idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1388
1389                 if (idx < 0) {
1390                         pr_err("unknown hash algorithm \"%s\"",
1391                                token);
1392                         return 0;
1393                 }
1394
1395                 if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1396                         pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1397                                token);
1398                         return 0;
1399                 }
1400
1401                 /* Add the hash algorithm to the 'allowed' bitfield */
1402                 res |= (1U << idx);
1403         }
1404
1405         return res;
1406 }
1407
1408 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1409 {
1410         struct audit_buffer *ab;
1411         char *from;
1412         char *p;
1413         bool eid_token; /* either euid or egid */
1414         struct ima_template_desc *template_desc;
1415         int result = 0;
1416
1417         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1418                                        AUDIT_INTEGRITY_POLICY_RULE);
1419
1420         entry->uid = INVALID_UID;
1421         entry->gid = INVALID_GID;
1422         entry->fowner = INVALID_UID;
1423         entry->fgroup = INVALID_GID;
1424         entry->uid_op = &uid_eq;
1425         entry->gid_op = &gid_eq;
1426         entry->fowner_op = &vfsuid_eq_kuid;
1427         entry->fgroup_op = &vfsgid_eq_kgid;
1428         entry->action = UNKNOWN;
1429         while ((p = strsep(&rule, " \t")) != NULL) {
1430                 substring_t args[MAX_OPT_ARGS];
1431                 int token;
1432                 unsigned long lnum;
1433
1434                 if (result < 0)
1435                         break;
1436                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1437                         continue;
1438                 token = match_token(p, policy_tokens, args);
1439                 switch (token) {
1440                 case Opt_measure:
1441                         ima_log_string(ab, "action", "measure");
1442
1443                         if (entry->action != UNKNOWN)
1444                                 result = -EINVAL;
1445
1446                         entry->action = MEASURE;
1447                         break;
1448                 case Opt_dont_measure:
1449                         ima_log_string(ab, "action", "dont_measure");
1450
1451                         if (entry->action != UNKNOWN)
1452                                 result = -EINVAL;
1453
1454                         entry->action = DONT_MEASURE;
1455                         break;
1456                 case Opt_appraise:
1457                         ima_log_string(ab, "action", "appraise");
1458
1459                         if (entry->action != UNKNOWN)
1460                                 result = -EINVAL;
1461
1462                         entry->action = APPRAISE;
1463                         break;
1464                 case Opt_dont_appraise:
1465                         ima_log_string(ab, "action", "dont_appraise");
1466
1467                         if (entry->action != UNKNOWN)
1468                                 result = -EINVAL;
1469
1470                         entry->action = DONT_APPRAISE;
1471                         break;
1472                 case Opt_audit:
1473                         ima_log_string(ab, "action", "audit");
1474
1475                         if (entry->action != UNKNOWN)
1476                                 result = -EINVAL;
1477
1478                         entry->action = AUDIT;
1479                         break;
1480                 case Opt_hash:
1481                         ima_log_string(ab, "action", "hash");
1482
1483                         if (entry->action != UNKNOWN)
1484                                 result = -EINVAL;
1485
1486                         entry->action = HASH;
1487                         break;
1488                 case Opt_dont_hash:
1489                         ima_log_string(ab, "action", "dont_hash");
1490
1491                         if (entry->action != UNKNOWN)
1492                                 result = -EINVAL;
1493
1494                         entry->action = DONT_HASH;
1495                         break;
1496                 case Opt_func:
1497                         ima_log_string(ab, "func", args[0].from);
1498
1499                         if (entry->func)
1500                                 result = -EINVAL;
1501
1502                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1503                                 entry->func = FILE_CHECK;
1504                         /* PATH_CHECK is for backwards compat */
1505                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1506                                 entry->func = FILE_CHECK;
1507                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1508                                 entry->func = MODULE_CHECK;
1509                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1510                                 entry->func = FIRMWARE_CHECK;
1511                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1512                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1513                                 entry->func = MMAP_CHECK;
1514                         else if ((strcmp(args[0].from, "MMAP_CHECK_REQPROT") == 0))
1515                                 entry->func = MMAP_CHECK_REQPROT;
1516                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1517                                 entry->func = BPRM_CHECK;
1518                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1519                                 entry->func = CREDS_CHECK;
1520                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1521                                  0)
1522                                 entry->func = KEXEC_KERNEL_CHECK;
1523                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1524                                  == 0)
1525                                 entry->func = KEXEC_INITRAMFS_CHECK;
1526                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1527                                 entry->func = POLICY_CHECK;
1528                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1529                                 entry->func = KEXEC_CMDLINE;
1530                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1531                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1532                                 entry->func = KEY_CHECK;
1533                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1534                                 entry->func = CRITICAL_DATA;
1535                         else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1536                                 entry->func = SETXATTR_CHECK;
1537                         else
1538                                 result = -EINVAL;
1539                         if (!result)
1540                                 entry->flags |= IMA_FUNC;
1541                         break;
1542                 case Opt_mask:
1543                         ima_log_string(ab, "mask", args[0].from);
1544
1545                         if (entry->mask)
1546                                 result = -EINVAL;
1547
1548                         from = args[0].from;
1549                         if (*from == '^')
1550                                 from++;
1551
1552                         if ((strcmp(from, "MAY_EXEC")) == 0)
1553                                 entry->mask = MAY_EXEC;
1554                         else if (strcmp(from, "MAY_WRITE") == 0)
1555                                 entry->mask = MAY_WRITE;
1556                         else if (strcmp(from, "MAY_READ") == 0)
1557                                 entry->mask = MAY_READ;
1558                         else if (strcmp(from, "MAY_APPEND") == 0)
1559                                 entry->mask = MAY_APPEND;
1560                         else
1561                                 result = -EINVAL;
1562                         if (!result)
1563                                 entry->flags |= (*args[0].from == '^')
1564                                      ? IMA_INMASK : IMA_MASK;
1565                         break;
1566                 case Opt_fsmagic:
1567                         ima_log_string(ab, "fsmagic", args[0].from);
1568
1569                         if (entry->fsmagic) {
1570                                 result = -EINVAL;
1571                                 break;
1572                         }
1573
1574                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1575                         if (!result)
1576                                 entry->flags |= IMA_FSMAGIC;
1577                         break;
1578                 case Opt_fsname:
1579                         ima_log_string(ab, "fsname", args[0].from);
1580
1581                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1582                         if (!entry->fsname) {
1583                                 result = -ENOMEM;
1584                                 break;
1585                         }
1586                         result = 0;
1587                         entry->flags |= IMA_FSNAME;
1588                         break;
1589                 case Opt_keyrings:
1590                         ima_log_string(ab, "keyrings", args[0].from);
1591
1592                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1593                             entry->keyrings) {
1594                                 result = -EINVAL;
1595                                 break;
1596                         }
1597
1598                         entry->keyrings = ima_alloc_rule_opt_list(args);
1599                         if (IS_ERR(entry->keyrings)) {
1600                                 result = PTR_ERR(entry->keyrings);
1601                                 entry->keyrings = NULL;
1602                                 break;
1603                         }
1604
1605                         entry->flags |= IMA_KEYRINGS;
1606                         break;
1607                 case Opt_label:
1608                         ima_log_string(ab, "label", args[0].from);
1609
1610                         if (entry->label) {
1611                                 result = -EINVAL;
1612                                 break;
1613                         }
1614
1615                         entry->label = ima_alloc_rule_opt_list(args);
1616                         if (IS_ERR(entry->label)) {
1617                                 result = PTR_ERR(entry->label);
1618                                 entry->label = NULL;
1619                                 break;
1620                         }
1621
1622                         entry->flags |= IMA_LABEL;
1623                         break;
1624                 case Opt_fsuuid:
1625                         ima_log_string(ab, "fsuuid", args[0].from);
1626
1627                         if (!uuid_is_null(&entry->fsuuid)) {
1628                                 result = -EINVAL;
1629                                 break;
1630                         }
1631
1632                         result = uuid_parse(args[0].from, &entry->fsuuid);
1633                         if (!result)
1634                                 entry->flags |= IMA_FSUUID;
1635                         break;
1636                 case Opt_uid_gt:
1637                 case Opt_euid_gt:
1638                         entry->uid_op = &uid_gt;
1639                         fallthrough;
1640                 case Opt_uid_lt:
1641                 case Opt_euid_lt:
1642                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1643                                 entry->uid_op = &uid_lt;
1644                         fallthrough;
1645                 case Opt_uid_eq:
1646                 case Opt_euid_eq:
1647                         eid_token = (token == Opt_euid_eq) ||
1648                                     (token == Opt_euid_gt) ||
1649                                     (token == Opt_euid_lt);
1650
1651                         ima_log_string_op(ab, eid_token ? "euid" : "uid",
1652                                           args[0].from, token);
1653
1654                         if (uid_valid(entry->uid)) {
1655                                 result = -EINVAL;
1656                                 break;
1657                         }
1658
1659                         result = kstrtoul(args[0].from, 10, &lnum);
1660                         if (!result) {
1661                                 entry->uid = make_kuid(current_user_ns(),
1662                                                        (uid_t) lnum);
1663                                 if (!uid_valid(entry->uid) ||
1664                                     (uid_t)lnum != lnum)
1665                                         result = -EINVAL;
1666                                 else
1667                                         entry->flags |= eid_token
1668                                             ? IMA_EUID : IMA_UID;
1669                         }
1670                         break;
1671                 case Opt_gid_gt:
1672                 case Opt_egid_gt:
1673                         entry->gid_op = &gid_gt;
1674                         fallthrough;
1675                 case Opt_gid_lt:
1676                 case Opt_egid_lt:
1677                         if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1678                                 entry->gid_op = &gid_lt;
1679                         fallthrough;
1680                 case Opt_gid_eq:
1681                 case Opt_egid_eq:
1682                         eid_token = (token == Opt_egid_eq) ||
1683                                     (token == Opt_egid_gt) ||
1684                                     (token == Opt_egid_lt);
1685
1686                         ima_log_string_op(ab, eid_token ? "egid" : "gid",
1687                                           args[0].from, token);
1688
1689                         if (gid_valid(entry->gid)) {
1690                                 result = -EINVAL;
1691                                 break;
1692                         }
1693
1694                         result = kstrtoul(args[0].from, 10, &lnum);
1695                         if (!result) {
1696                                 entry->gid = make_kgid(current_user_ns(),
1697                                                        (gid_t)lnum);
1698                                 if (!gid_valid(entry->gid) ||
1699                                     (((gid_t)lnum) != lnum))
1700                                         result = -EINVAL;
1701                                 else
1702                                         entry->flags |= eid_token
1703                                             ? IMA_EGID : IMA_GID;
1704                         }
1705                         break;
1706                 case Opt_fowner_gt:
1707                         entry->fowner_op = &vfsuid_gt_kuid;
1708                         fallthrough;
1709                 case Opt_fowner_lt:
1710                         if (token == Opt_fowner_lt)
1711                                 entry->fowner_op = &vfsuid_lt_kuid;
1712                         fallthrough;
1713                 case Opt_fowner_eq:
1714                         ima_log_string_op(ab, "fowner", args[0].from, token);
1715
1716                         if (uid_valid(entry->fowner)) {
1717                                 result = -EINVAL;
1718                                 break;
1719                         }
1720
1721                         result = kstrtoul(args[0].from, 10, &lnum);
1722                         if (!result) {
1723                                 entry->fowner = make_kuid(current_user_ns(),
1724                                                           (uid_t)lnum);
1725                                 if (!uid_valid(entry->fowner) ||
1726                                     (((uid_t)lnum) != lnum))
1727                                         result = -EINVAL;
1728                                 else
1729                                         entry->flags |= IMA_FOWNER;
1730                         }
1731                         break;
1732                 case Opt_fgroup_gt:
1733                         entry->fgroup_op = &vfsgid_gt_kgid;
1734                         fallthrough;
1735                 case Opt_fgroup_lt:
1736                         if (token == Opt_fgroup_lt)
1737                                 entry->fgroup_op = &vfsgid_lt_kgid;
1738                         fallthrough;
1739                 case Opt_fgroup_eq:
1740                         ima_log_string_op(ab, "fgroup", args[0].from, token);
1741
1742                         if (gid_valid(entry->fgroup)) {
1743                                 result = -EINVAL;
1744                                 break;
1745                         }
1746
1747                         result = kstrtoul(args[0].from, 10, &lnum);
1748                         if (!result) {
1749                                 entry->fgroup = make_kgid(current_user_ns(),
1750                                                           (gid_t)lnum);
1751                                 if (!gid_valid(entry->fgroup) ||
1752                                     (((gid_t)lnum) != lnum))
1753                                         result = -EINVAL;
1754                                 else
1755                                         entry->flags |= IMA_FGROUP;
1756                         }
1757                         break;
1758                 case Opt_obj_user:
1759                         ima_log_string(ab, "obj_user", args[0].from);
1760                         result = ima_lsm_rule_init(entry, args,
1761                                                    LSM_OBJ_USER,
1762                                                    AUDIT_OBJ_USER);
1763                         break;
1764                 case Opt_obj_role:
1765                         ima_log_string(ab, "obj_role", args[0].from);
1766                         result = ima_lsm_rule_init(entry, args,
1767                                                    LSM_OBJ_ROLE,
1768                                                    AUDIT_OBJ_ROLE);
1769                         break;
1770                 case Opt_obj_type:
1771                         ima_log_string(ab, "obj_type", args[0].from);
1772                         result = ima_lsm_rule_init(entry, args,
1773                                                    LSM_OBJ_TYPE,
1774                                                    AUDIT_OBJ_TYPE);
1775                         break;
1776                 case Opt_subj_user:
1777                         ima_log_string(ab, "subj_user", args[0].from);
1778                         result = ima_lsm_rule_init(entry, args,
1779                                                    LSM_SUBJ_USER,
1780                                                    AUDIT_SUBJ_USER);
1781                         break;
1782                 case Opt_subj_role:
1783                         ima_log_string(ab, "subj_role", args[0].from);
1784                         result = ima_lsm_rule_init(entry, args,
1785                                                    LSM_SUBJ_ROLE,
1786                                                    AUDIT_SUBJ_ROLE);
1787                         break;
1788                 case Opt_subj_type:
1789                         ima_log_string(ab, "subj_type", args[0].from);
1790                         result = ima_lsm_rule_init(entry, args,
1791                                                    LSM_SUBJ_TYPE,
1792                                                    AUDIT_SUBJ_TYPE);
1793                         break;
1794                 case Opt_digest_type:
1795                         ima_log_string(ab, "digest_type", args[0].from);
1796                         if (entry->flags & IMA_DIGSIG_REQUIRED)
1797                                 result = -EINVAL;
1798                         else if ((strcmp(args[0].from, "verity")) == 0)
1799                                 entry->flags |= IMA_VERITY_REQUIRED;
1800                         else
1801                                 result = -EINVAL;
1802                         break;
1803                 case Opt_appraise_type:
1804                         ima_log_string(ab, "appraise_type", args[0].from);
1805
1806                         if ((strcmp(args[0].from, "imasig")) == 0) {
1807                                 if (entry->flags & IMA_VERITY_REQUIRED)
1808                                         result = -EINVAL;
1809                                 else
1810                                         entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
1811                         } else if (strcmp(args[0].from, "sigv3") == 0) {
1812                                 /* Only fsverity supports sigv3 for now */
1813                                 if (entry->flags & IMA_VERITY_REQUIRED)
1814                                         entry->flags |= IMA_DIGSIG_REQUIRED | IMA_CHECK_BLACKLIST;
1815                                 else
1816                                         result = -EINVAL;
1817                         } else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1818                                  strcmp(args[0].from, "imasig|modsig") == 0) {
1819                                 if (entry->flags & IMA_VERITY_REQUIRED)
1820                                         result = -EINVAL;
1821                                 else
1822                                         entry->flags |= IMA_DIGSIG_REQUIRED |
1823                                                 IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST;
1824                         } else {
1825                                 result = -EINVAL;
1826                         }
1827                         break;
1828                 case Opt_appraise_flag:
1829                         ima_log_string(ab, "appraise_flag", args[0].from);
1830                         break;
1831                 case Opt_appraise_algos:
1832                         ima_log_string(ab, "appraise_algos", args[0].from);
1833
1834                         if (entry->allowed_algos) {
1835                                 result = -EINVAL;
1836                                 break;
1837                         }
1838
1839                         entry->allowed_algos =
1840                                 ima_parse_appraise_algos(args[0].from);
1841                         /* invalid or empty list of algorithms */
1842                         if (!entry->allowed_algos) {
1843                                 result = -EINVAL;
1844                                 break;
1845                         }
1846
1847                         entry->flags |= IMA_VALIDATE_ALGOS;
1848
1849                         break;
1850                 case Opt_permit_directio:
1851                         entry->flags |= IMA_PERMIT_DIRECTIO;
1852                         break;
1853                 case Opt_pcr:
1854                         ima_log_string(ab, "pcr", args[0].from);
1855
1856                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1857                         if (result || INVALID_PCR(entry->pcr))
1858                                 result = -EINVAL;
1859                         else
1860                                 entry->flags |= IMA_PCR;
1861
1862                         break;
1863                 case Opt_template:
1864                         ima_log_string(ab, "template", args[0].from);
1865                         if (entry->action != MEASURE) {
1866                                 result = -EINVAL;
1867                                 break;
1868                         }
1869                         template_desc = lookup_template_desc(args[0].from);
1870                         if (!template_desc || entry->template) {
1871                                 result = -EINVAL;
1872                                 break;
1873                         }
1874
1875                         /*
1876                          * template_desc_init_fields() does nothing if
1877                          * the template is already initialised, so
1878                          * it's safe to do this unconditionally
1879                          */
1880                         template_desc_init_fields(template_desc->fmt,
1881                                                  &(template_desc->fields),
1882                                                  &(template_desc->num_fields));
1883                         entry->template = template_desc;
1884                         break;
1885                 case Opt_err:
1886                         ima_log_string(ab, "UNKNOWN", p);
1887                         result = -EINVAL;
1888                         break;
1889                 }
1890         }
1891         if (!result && !ima_validate_rule(entry))
1892                 result = -EINVAL;
1893         else if (entry->action == APPRAISE)
1894                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1895
1896         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1897                 template_desc = entry->template ? entry->template :
1898                                                   ima_template_desc_current();
1899                 check_template_modsig(template_desc);
1900         }
1901
1902         /* d-ngv2 template field recommended for unsigned fs-verity digests */
1903         if (!result && entry->action == MEASURE &&
1904             entry->flags & IMA_VERITY_REQUIRED) {
1905                 template_desc = entry->template ? entry->template :
1906                                                   ima_template_desc_current();
1907                 check_template_field(template_desc, "d-ngv2",
1908                                      "verity rules should include d-ngv2");
1909         }
1910
1911         audit_log_format(ab, "res=%d", !result);
1912         audit_log_end(ab);
1913         return result;
1914 }
1915
1916 /**
1917  * ima_parse_add_rule - add a rule to ima_policy_rules
1918  * @rule: ima measurement policy rule
1919  *
1920  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1921  * Returns the length of the rule parsed, an error code on failure
1922  */
1923 ssize_t ima_parse_add_rule(char *rule)
1924 {
1925         static const char op[] = "update_policy";
1926         char *p;
1927         struct ima_rule_entry *entry;
1928         ssize_t result, len;
1929         int audit_info = 0;
1930
1931         p = strsep(&rule, "\n");
1932         len = strlen(p) + 1;
1933         p += strspn(p, " \t");
1934
1935         if (*p == '#' || *p == '\0')
1936                 return len;
1937
1938         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1939         if (!entry) {
1940                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1941                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1942                 return -ENOMEM;
1943         }
1944
1945         INIT_LIST_HEAD(&entry->list);
1946
1947         result = ima_parse_rule(p, entry);
1948         if (result) {
1949                 ima_free_rule(entry);
1950                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1951                                     NULL, op, "invalid-policy", result,
1952                                     audit_info);
1953                 return result;
1954         }
1955
1956         list_add_tail(&entry->list, &ima_temp_rules);
1957
1958         return len;
1959 }
1960
1961 /**
1962  * ima_delete_rules() - called to cleanup invalid in-flight policy.
1963  *
1964  * We don't need locking as we operate on the temp list, which is
1965  * different from the active one.  There is also only one user of
1966  * ima_delete_rules() at a time.
1967  */
1968 void ima_delete_rules(void)
1969 {
1970         struct ima_rule_entry *entry, *tmp;
1971
1972         temp_ima_appraise = 0;
1973         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1974                 list_del(&entry->list);
1975                 ima_free_rule(entry);
1976         }
1977 }
1978
1979 #define __ima_hook_stringify(func, str) (#func),
1980
1981 const char *const func_tokens[] = {
1982         __ima_hooks(__ima_hook_stringify)
1983 };
1984
1985 #ifdef  CONFIG_IMA_READ_POLICY
1986 enum {
1987         mask_exec = 0, mask_write, mask_read, mask_append
1988 };
1989
1990 static const char *const mask_tokens[] = {
1991         "^MAY_EXEC",
1992         "^MAY_WRITE",
1993         "^MAY_READ",
1994         "^MAY_APPEND"
1995 };
1996
1997 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1998 {
1999         loff_t l = *pos;
2000         struct ima_rule_entry *entry;
2001         struct list_head *ima_rules_tmp;
2002
2003         rcu_read_lock();
2004         ima_rules_tmp = rcu_dereference(ima_rules);
2005         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2006                 if (!l--) {
2007                         rcu_read_unlock();
2008                         return entry;
2009                 }
2010         }
2011         rcu_read_unlock();
2012         return NULL;
2013 }
2014
2015 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
2016 {
2017         struct ima_rule_entry *entry = v;
2018
2019         rcu_read_lock();
2020         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
2021         rcu_read_unlock();
2022         (*pos)++;
2023
2024         return (&entry->list == &ima_default_rules ||
2025                 &entry->list == &ima_policy_rules) ? NULL : entry;
2026 }
2027
2028 void ima_policy_stop(struct seq_file *m, void *v)
2029 {
2030 }
2031
2032 #define pt(token)       policy_tokens[token].pattern
2033 #define mt(token)       mask_tokens[token]
2034
2035 /*
2036  * policy_func_show - display the ima_hooks policy rule
2037  */
2038 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
2039 {
2040         if (func > 0 && func < MAX_CHECK)
2041                 seq_printf(m, "func=%s ", func_tokens[func]);
2042         else
2043                 seq_printf(m, "func=%d ", func);
2044 }
2045
2046 static void ima_show_rule_opt_list(struct seq_file *m,
2047                                    const struct ima_rule_opt_list *opt_list)
2048 {
2049         size_t i;
2050
2051         for (i = 0; i < opt_list->count; i++)
2052                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
2053 }
2054
2055 static void ima_policy_show_appraise_algos(struct seq_file *m,
2056                                            unsigned int allowed_hashes)
2057 {
2058         int idx, list_size = 0;
2059
2060         for (idx = 0; idx < HASH_ALGO__LAST; idx++) {
2061                 if (!(allowed_hashes & (1U << idx)))
2062                         continue;
2063
2064                 /* only add commas if the list contains multiple entries */
2065                 if (list_size++)
2066                         seq_puts(m, ",");
2067
2068                 seq_puts(m, hash_algo_name[idx]);
2069         }
2070 }
2071
2072 int ima_policy_show(struct seq_file *m, void *v)
2073 {
2074         struct ima_rule_entry *entry = v;
2075         int i;
2076         char tbuf[64] = {0,};
2077         int offset = 0;
2078
2079         rcu_read_lock();
2080
2081         /* Do not print rules with inactive LSM labels */
2082         for (i = 0; i < MAX_LSM_RULES; i++) {
2083                 if (entry->lsm[i].args_p && !entry->lsm[i].rule) {
2084                         rcu_read_unlock();
2085                         return 0;
2086                 }
2087         }
2088
2089         if (entry->action & MEASURE)
2090                 seq_puts(m, pt(Opt_measure));
2091         if (entry->action & DONT_MEASURE)
2092                 seq_puts(m, pt(Opt_dont_measure));
2093         if (entry->action & APPRAISE)
2094                 seq_puts(m, pt(Opt_appraise));
2095         if (entry->action & DONT_APPRAISE)
2096                 seq_puts(m, pt(Opt_dont_appraise));
2097         if (entry->action & AUDIT)
2098                 seq_puts(m, pt(Opt_audit));
2099         if (entry->action & HASH)
2100                 seq_puts(m, pt(Opt_hash));
2101         if (entry->action & DONT_HASH)
2102                 seq_puts(m, pt(Opt_dont_hash));
2103
2104         seq_puts(m, " ");
2105
2106         if (entry->flags & IMA_FUNC)
2107                 policy_func_show(m, entry->func);
2108
2109         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
2110                 if (entry->flags & IMA_MASK)
2111                         offset = 1;
2112                 if (entry->mask & MAY_EXEC)
2113                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
2114                 if (entry->mask & MAY_WRITE)
2115                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
2116                 if (entry->mask & MAY_READ)
2117                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
2118                 if (entry->mask & MAY_APPEND)
2119                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
2120                 seq_puts(m, " ");
2121         }
2122
2123         if (entry->flags & IMA_FSMAGIC) {
2124                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
2125                 seq_printf(m, pt(Opt_fsmagic), tbuf);
2126                 seq_puts(m, " ");
2127         }
2128
2129         if (entry->flags & IMA_FSNAME) {
2130                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
2131                 seq_printf(m, pt(Opt_fsname), tbuf);
2132                 seq_puts(m, " ");
2133         }
2134
2135         if (entry->flags & IMA_KEYRINGS) {
2136                 seq_puts(m, "keyrings=");
2137                 ima_show_rule_opt_list(m, entry->keyrings);
2138                 seq_puts(m, " ");
2139         }
2140
2141         if (entry->flags & IMA_LABEL) {
2142                 seq_puts(m, "label=");
2143                 ima_show_rule_opt_list(m, entry->label);
2144                 seq_puts(m, " ");
2145         }
2146
2147         if (entry->flags & IMA_PCR) {
2148                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
2149                 seq_printf(m, pt(Opt_pcr), tbuf);
2150                 seq_puts(m, " ");
2151         }
2152
2153         if (entry->flags & IMA_FSUUID) {
2154                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
2155                 seq_puts(m, " ");
2156         }
2157
2158         if (entry->flags & IMA_UID) {
2159                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2160                 if (entry->uid_op == &uid_gt)
2161                         seq_printf(m, pt(Opt_uid_gt), tbuf);
2162                 else if (entry->uid_op == &uid_lt)
2163                         seq_printf(m, pt(Opt_uid_lt), tbuf);
2164                 else
2165                         seq_printf(m, pt(Opt_uid_eq), tbuf);
2166                 seq_puts(m, " ");
2167         }
2168
2169         if (entry->flags & IMA_EUID) {
2170                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
2171                 if (entry->uid_op == &uid_gt)
2172                         seq_printf(m, pt(Opt_euid_gt), tbuf);
2173                 else if (entry->uid_op == &uid_lt)
2174                         seq_printf(m, pt(Opt_euid_lt), tbuf);
2175                 else
2176                         seq_printf(m, pt(Opt_euid_eq), tbuf);
2177                 seq_puts(m, " ");
2178         }
2179
2180         if (entry->flags & IMA_GID) {
2181                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2182                 if (entry->gid_op == &gid_gt)
2183                         seq_printf(m, pt(Opt_gid_gt), tbuf);
2184                 else if (entry->gid_op == &gid_lt)
2185                         seq_printf(m, pt(Opt_gid_lt), tbuf);
2186                 else
2187                         seq_printf(m, pt(Opt_gid_eq), tbuf);
2188                 seq_puts(m, " ");
2189         }
2190
2191         if (entry->flags & IMA_EGID) {
2192                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->gid));
2193                 if (entry->gid_op == &gid_gt)
2194                         seq_printf(m, pt(Opt_egid_gt), tbuf);
2195                 else if (entry->gid_op == &gid_lt)
2196                         seq_printf(m, pt(Opt_egid_lt), tbuf);
2197                 else
2198                         seq_printf(m, pt(Opt_egid_eq), tbuf);
2199                 seq_puts(m, " ");
2200         }
2201
2202         if (entry->flags & IMA_FOWNER) {
2203                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
2204                 if (entry->fowner_op == &vfsuid_gt_kuid)
2205                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
2206                 else if (entry->fowner_op == &vfsuid_lt_kuid)
2207                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
2208                 else
2209                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
2210                 seq_puts(m, " ");
2211         }
2212
2213         if (entry->flags & IMA_FGROUP) {
2214                 snprintf(tbuf, sizeof(tbuf), "%d", __kgid_val(entry->fgroup));
2215                 if (entry->fgroup_op == &vfsgid_gt_kgid)
2216                         seq_printf(m, pt(Opt_fgroup_gt), tbuf);
2217                 else if (entry->fgroup_op == &vfsgid_lt_kgid)
2218                         seq_printf(m, pt(Opt_fgroup_lt), tbuf);
2219                 else
2220                         seq_printf(m, pt(Opt_fgroup_eq), tbuf);
2221                 seq_puts(m, " ");
2222         }
2223
2224         if (entry->flags & IMA_VALIDATE_ALGOS) {
2225                 seq_puts(m, "appraise_algos=");
2226                 ima_policy_show_appraise_algos(m, entry->allowed_algos);
2227                 seq_puts(m, " ");
2228         }
2229
2230         for (i = 0; i < MAX_LSM_RULES; i++) {
2231                 if (entry->lsm[i].rule) {
2232                         switch (i) {
2233                         case LSM_OBJ_USER:
2234                                 seq_printf(m, pt(Opt_obj_user),
2235                                            entry->lsm[i].args_p);
2236                                 break;
2237                         case LSM_OBJ_ROLE:
2238                                 seq_printf(m, pt(Opt_obj_role),
2239                                            entry->lsm[i].args_p);
2240                                 break;
2241                         case LSM_OBJ_TYPE:
2242                                 seq_printf(m, pt(Opt_obj_type),
2243                                            entry->lsm[i].args_p);
2244                                 break;
2245                         case LSM_SUBJ_USER:
2246                                 seq_printf(m, pt(Opt_subj_user),
2247                                            entry->lsm[i].args_p);
2248                                 break;
2249                         case LSM_SUBJ_ROLE:
2250                                 seq_printf(m, pt(Opt_subj_role),
2251                                            entry->lsm[i].args_p);
2252                                 break;
2253                         case LSM_SUBJ_TYPE:
2254                                 seq_printf(m, pt(Opt_subj_type),
2255                                            entry->lsm[i].args_p);
2256                                 break;
2257                         }
2258                         seq_puts(m, " ");
2259                 }
2260         }
2261         if (entry->template)
2262                 seq_printf(m, "template=%s ", entry->template->name);
2263         if (entry->flags & IMA_DIGSIG_REQUIRED) {
2264                 if (entry->flags & IMA_VERITY_REQUIRED)
2265                         seq_puts(m, "appraise_type=sigv3 ");
2266                 else if (entry->flags & IMA_MODSIG_ALLOWED)
2267                         seq_puts(m, "appraise_type=imasig|modsig ");
2268                 else
2269                         seq_puts(m, "appraise_type=imasig ");
2270         }
2271         if (entry->flags & IMA_VERITY_REQUIRED)
2272                 seq_puts(m, "digest_type=verity ");
2273         if (entry->flags & IMA_PERMIT_DIRECTIO)
2274                 seq_puts(m, "permit_directio ");
2275         rcu_read_unlock();
2276         seq_puts(m, "\n");
2277         return 0;
2278 }
2279 #endif  /* CONFIG_IMA_READ_POLICY */
2280
2281 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2282 /*
2283  * ima_appraise_signature: whether IMA will appraise a given function using
2284  * an IMA digital signature. This is restricted to cases where the kernel
2285  * has a set of built-in trusted keys in order to avoid an attacker simply
2286  * loading additional keys.
2287  */
2288 bool ima_appraise_signature(enum kernel_read_file_id id)
2289 {
2290         struct ima_rule_entry *entry;
2291         bool found = false;
2292         enum ima_hooks func;
2293         struct list_head *ima_rules_tmp;
2294
2295         if (id >= READING_MAX_ID)
2296                 return false;
2297
2298         if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2299             && security_locked_down(LOCKDOWN_KEXEC))
2300                 return false;
2301
2302         func = read_idmap[id] ?: FILE_CHECK;
2303
2304         rcu_read_lock();
2305         ima_rules_tmp = rcu_dereference(ima_rules);
2306         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2307                 if (entry->action != APPRAISE)
2308                         continue;
2309
2310                 /*
2311                  * A generic entry will match, but otherwise require that it
2312                  * match the func we're looking for
2313                  */
2314                 if (entry->func && entry->func != func)
2315                         continue;
2316
2317                 /*
2318                  * We require this to be a digital signature, not a raw IMA
2319                  * hash.
2320                  */
2321                 if (entry->flags & IMA_DIGSIG_REQUIRED)
2322                         found = true;
2323
2324                 /*
2325                  * We've found a rule that matches, so break now even if it
2326                  * didn't require a digital signature - a later rule that does
2327                  * won't override it, so would be a false positive.
2328                  */
2329                 break;
2330         }
2331
2332         rcu_read_unlock();
2333         return found;
2334 }
2335 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */