security/integrity/ima/ima_policy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 IBM Corporation
   4  * Author: Mimi Zohar <zohar@us.ibm.com>
   5  *
   6  * ima_policy.c
   7  *      - initialize default measure policy rules
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/kernel_read_file.h>
  13 #include <linux/fs.h>
  14 #include <linux/security.h>
  15 #include <linux/magic.h>
  16 #include <linux/parser.h>
  17 #include <linux/slab.h>
  18 #include <linux/rculist.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/ima.h>
  21
  22 #include "ima.h"
  23
  24 /* flags definitions */
  25 #define IMA_FUNC        0x0001
  26 #define IMA_MASK        0x0002
  27 #define IMA_FSMAGIC     0x0004
  28 #define IMA_UID         0x0008
  29 #define IMA_FOWNER      0x0010
  30 #define IMA_FSUUID      0x0020
  31 #define IMA_INMASK      0x0040
  32 #define IMA_EUID        0x0080
  33 #define IMA_PCR         0x0100
  34 #define IMA_FSNAME      0x0200
  35 #define IMA_KEYRINGS    0x0400
  36 #define IMA_LABEL       0x0800
  37 #define IMA_VALIDATE_ALGOS      0x1000
  38 #define IMA_GID         0x2000
  39 #define IMA_EGID        0x4000
  40 #define IMA_FGROUP      0x8000
  41
  42 #define UNKNOWN         0
  43 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  44 #define DONT_MEASURE    0x0002
  45 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  46 #define DONT_APPRAISE   0x0008
  47 #define AUDIT           0x0040
  48 #define HASH            0x0100
  49 #define DONT_HASH       0x0200
  50
  51 #define INVALID_PCR(a) (((a) < 0) || \
  52         (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
  53
  54 int ima_policy_flag;
  55 static int temp_ima_appraise;
  56 static int build_ima_appraise __ro_after_init;
  57
  58 atomic_t ima_setxattr_allowed_hash_algorithms;
  59
  60 #define MAX_LSM_RULES 6
  61 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  62         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  63 };
  64
  65 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  66
  67 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
  68
  69 struct ima_rule_opt_list {
  70         size_t count;
  71         char *items[];
  72 };
  73
  74 /*
  75  * These comparators are needed nowhere outside of ima so just define them here.
  76  * This pattern should hopefully never be needed outside of ima.
  77  */
  78 static inline bool vfsuid_gt_kuid(vfsuid_t vfsuid, kuid_t kuid)
  79 {
  80         return __vfsuid_val(vfsuid) > __kuid_val(kuid);
  81 }
  82
  83 static inline bool vfsgid_gt_kgid(vfsgid_t vfsgid, kgid_t kgid)
  84 {
  85         return __vfsgid_val(vfsgid) > __kgid_val(kgid);
  86 }
  87
  88 static inline bool vfsuid_lt_kuid(vfsuid_t vfsuid, kuid_t kuid)
  89 {
  90         return __vfsuid_val(vfsuid) < __kuid_val(kuid);
  91 }
  92
  93 static inline bool vfsgid_lt_kgid(vfsgid_t vfsgid, kgid_t kgid)
  94 {
  95         return __vfsgid_val(vfsgid) < __kgid_val(kgid);
  96 }
  97
  98 struct ima_rule_entry {
  99         struct list_head list;
 100         int action;
 101         unsigned int flags;
 102         enum ima_hooks func;
 103         int mask;
 104         unsigned long fsmagic;
 105         uuid_t fsuuid;
 106         kuid_t uid;
 107         kgid_t gid;
 108         kuid_t fowner;
 109         kgid_t fgroup;
 110         bool (*uid_op)(kuid_t cred_uid, kuid_t rule_uid);    /* Handlers for operators       */
 111         bool (*gid_op)(kgid_t cred_gid, kgid_t rule_gid);
 112         bool (*fowner_op)(vfsuid_t vfsuid, kuid_t rule_uid); /* vfsuid_eq_kuid(), vfsuid_gt_kuid(), vfsuid_lt_kuid() */
 113         bool (*fgroup_op)(vfsgid_t vfsgid, kgid_t rule_gid); /* vfsgid_eq_kgid(), vfsgid_gt_kgid(), vfsgid_lt_kgid() */
 114         int pcr;
 115         unsigned int allowed_algos; /* bitfield of allowed hash algorithms */
 116         struct {
 117                 void *rule;     /* LSM file metadata specific */
 118                 char *args_p;   /* audit value */
 119                 int type;       /* audit type */
 120         } lsm[MAX_LSM_RULES];
 121         char *fsname;
 122         struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
 123         struct ima_rule_opt_list *label; /* Measure data grouped under this label */
 124         struct ima_template_desc *template;
 125 };
 126
 127 /*
 128  * sanity check in case the kernels gains more hash algorithms that can
 129  * fit in an unsigned int
 130  */
 131 static_assert(
 132         8 * sizeof(unsigned int) >= HASH_ALGO__LAST,
 133         "The bitfield allowed_algos in ima_rule_entry is too small to contain all the supported hash algorithms, consider using a bigger type");
 134
 135 /*
 136  * Without LSM specific knowledge, the default policy can only be
 137  * written in terms of .action, .func, .mask, .fsmagic, .uid, .gid,
 138  * .fowner, and .fgroup
 139  */
 140
 141 /*
 142  * The minimum rule set to allow for full TCB coverage.  Measures all files
 143  * opened or mmap for exec and everything read by root.  Dangerous because
 144  * normal users can easily run the machine out of memory simply building
 145  * and running executables.
 146  */
 147 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
 148         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 149         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 150         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 151         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 152         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 153         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 154         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 155         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 156         {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 157         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
 158          .flags = IMA_FSMAGIC},
 159         {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
 160          .flags = IMA_FSMAGIC},
 161         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 162         {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
 163 };
 164
 165 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
 166         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 167          .flags = IMA_FUNC | IMA_MASK},
 168         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 169          .flags = IMA_FUNC | IMA_MASK},
 170         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 171          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 172          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 173         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 174         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 175 };
 176
 177 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
 178         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 179          .flags = IMA_FUNC | IMA_MASK},
 180         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 181          .flags = IMA_FUNC | IMA_MASK},
 182         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 183          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 184          .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 185         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 186          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 187          .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 188         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 189         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 190         {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
 191 };
 192
 193 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
 194         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 195         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 196         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 197         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 198         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 199         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 200         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 201         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 202         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 203         {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 204         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 205         {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
 206         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 207         {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 208 #ifdef CONFIG_IMA_WRITE_POLICY
 209         {.action = APPRAISE, .func = POLICY_CHECK,
 210         .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 211 #endif
 212 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 213         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
 214          .flags = IMA_FOWNER},
 215 #else
 216         /* force signature */
 217         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &vfsuid_eq_kuid,
 218          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 219 #endif
 220 };
 221
 222 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 223 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
 224         {.action = APPRAISE, .func = MODULE_CHECK,
 225          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 226 #endif
 227 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
 228         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 229          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 230 #endif
 231 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
 232         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 233          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 234 #endif
 235 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
 236         {.action = APPRAISE, .func = POLICY_CHECK,
 237          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 238 #endif
 239 };
 240
 241 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 242         {.action = APPRAISE, .func = MODULE_CHECK,
 243          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 244         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 245          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 246         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 247          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 248         {.action = APPRAISE, .func = POLICY_CHECK,
 249          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 250 };
 251
 252 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
 253         {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
 254 };
 255
 256 /* An array of architecture specific rules */
 257 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 258
 259 static LIST_HEAD(ima_default_rules);
 260 static LIST_HEAD(ima_policy_rules);
 261 static LIST_HEAD(ima_temp_rules);
 262 static struct list_head __rcu *ima_rules = (struct list_head __rcu *)(&ima_default_rules);
 263
 264 static int ima_policy __initdata;
 265
 266 static int __init default_measure_policy_setup(char *str)
 267 {
 268         if (ima_policy)
 269                 return 1;
 270
 271         ima_policy = ORIGINAL_TCB;
 272         return 1;
 273 }
 274 __setup("ima_tcb", default_measure_policy_setup);
 275
 276 static bool ima_use_appraise_tcb __initdata;
 277 static bool ima_use_secure_boot __initdata;
 278 static bool ima_use_critical_data __initdata;
 279 static bool ima_fail_unverifiable_sigs __ro_after_init;
 280 static int __init policy_setup(char *str)
 281 {
 282         char *p;
 283
 284         while ((p = strsep(&str, " |\n")) != NULL) {
 285                 if (*p == ' ')
 286                         continue;
 287                 if ((strcmp(p, "tcb") == 0) && !ima_policy)
 288                         ima_policy = DEFAULT_TCB;
 289                 else if (strcmp(p, "appraise_tcb") == 0)
 290                         ima_use_appraise_tcb = true;
 291                 else if (strcmp(p, "secure_boot") == 0)
 292                         ima_use_secure_boot = true;
 293                 else if (strcmp(p, "critical_data") == 0)
 294                         ima_use_critical_data = true;
 295                 else if (strcmp(p, "fail_securely") == 0)
 296                         ima_fail_unverifiable_sigs = true;
 297                 else
 298                         pr_err("policy \"%s\" not found", p);
 299         }
 300
 301         return 1;
 302 }
 303 __setup("ima_policy=", policy_setup);
 304
 305 static int __init default_appraise_policy_setup(char *str)
 306 {
 307         ima_use_appraise_tcb = true;
 308         return 1;
 309 }
 310 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 311
 312 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 313 {
 314         struct ima_rule_opt_list *opt_list;
 315         size_t count = 0;
 316         char *src_copy;
 317         char *cur, *next;
 318         size_t i;
 319
 320         src_copy = match_strdup(src);
 321         if (!src_copy)
 322                 return ERR_PTR(-ENOMEM);
 323
 324         next = src_copy;
 325         while ((cur = strsep(&next, "|"))) {
 326                 /* Don't accept an empty list item */
 327                 if (!(*cur)) {
 328                         kfree(src_copy);
 329                         return ERR_PTR(-EINVAL);
 330                 }
 331                 count++;
 332         }
 333
 334         /* Don't accept an empty list */
 335         if (!count) {
 336                 kfree(src_copy);
 337                 return ERR_PTR(-EINVAL);
 338         }
 339
 340         opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
 341         if (!opt_list) {
 342                 kfree(src_copy);
 343                 return ERR_PTR(-ENOMEM);
 344         }
 345
 346         /*
 347          * strsep() has already replaced all instances of '|' with '\0',
 348          * leaving a byte sequence of NUL-terminated strings. Reference each
 349          * string with the array of items.
 350          *
 351          * IMPORTANT: Ownership of the allocated buffer is transferred from
 352          * src_copy to the first element in the items array. To free the
 353          * buffer, kfree() must only be called on the first element of the
 354          * array.
 355          */
 356         for (i = 0, cur = src_copy; i < count; i++) {
 357                 opt_list->items[i] = cur;
 358                 cur = strchr(cur, '\0') + 1;
 359         }
 360         opt_list->count = count;
 361
 362         return opt_list;
 363 }
 364
 365 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 366 {
 367         if (!opt_list)
 368                 return;
 369
 370         if (opt_list->count) {
 371                 kfree(opt_list->items[0]);
 372                 opt_list->count = 0;
 373         }
 374
 375         kfree(opt_list);
 376 }
 377
 378 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 379 {
 380         int i;
 381
 382         for (i = 0; i < MAX_LSM_RULES; i++) {
 383                 ima_filter_rule_free(entry->lsm[i].rule);
 384                 kfree(entry->lsm[i].args_p);
 385         }
 386 }
 387
 388 static void ima_free_rule(struct ima_rule_entry *entry)
 389 {
 390         if (!entry)
 391                 return;
 392
 393         /*
 394          * entry->template->fields may be allocated in ima_parse_rule() but that
 395          * reference is owned by the corresponding ima_template_desc element in
 396          * the defined_templates list and cannot be freed here
 397          */
 398         kfree(entry->fsname);
 399         ima_free_rule_opt_list(entry->keyrings);
 400         ima_lsm_free_rule(entry);
 401         kfree(entry);
 402 }
 403
 404 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 405 {
 406         struct ima_rule_entry *nentry;
 407         int i;
 408
 409         /*
 410          * Immutable elements are copied over as pointers and data; only
 411          * lsm rules can change
 412          */
 413         nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
 414         if (!nentry)
 415                 return NULL;
 416
 417         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 418
 419         for (i = 0; i < MAX_LSM_RULES; i++) {
 420                 if (!entry->lsm[i].args_p)
 421                         continue;
 422
 423                 nentry->lsm[i].type = entry->lsm[i].type;
 424                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 425
 426                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 427                                      nentry->lsm[i].args_p,
 428                                      &nentry->lsm[i].rule);
 429                 if (!nentry->lsm[i].rule)
 430                         pr_warn("rule for LSM \'%s\' is undefined\n",
 431                                 nentry->lsm[i].args_p);
 432         }
 433         return nentry;
 434 }
 435
 436 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 437 {
 438         int i;
 439         struct ima_rule_entry *nentry;
 440
 441         nentry = ima_lsm_copy_rule(entry);
 442         if (!nentry)
 443                 return -ENOMEM;
 444
 445         list_replace_rcu(&entry->list, &nentry->list);
 446         synchronize_rcu();
 447         /*
 448          * ima_lsm_copy_rule() shallow copied all references, except for the
 449          * LSM references, from entry to nentry so we only want to free the LSM
 450          * references and the entry itself. All other memory references will now
 451          * be owned by nentry.
 452          */
 453         for (i = 0; i < MAX_LSM_RULES; i++)
 454                 ima_filter_rule_free(entry->lsm[i].rule);
 455         kfree(entry);
 456
 457         return 0;
 458 }
 459
 460 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 461 {
 462         int i;
 463
 464         for (i = 0; i < MAX_LSM_RULES; i++)
 465                 if (entry->lsm[i].args_p)
 466                         return true;
 467
 468         return false;
 469 }
 470
 471 /*
 472  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 473  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 474  * the reloaded LSM policy.
 475  */
 476 static void ima_lsm_update_rules(void)
 477 {
 478         struct ima_rule_entry *entry, *e;
 479         int result;
 480
 481         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 482                 if (!ima_rule_contains_lsm_cond(entry))
 483                         continue;
 484
 485                 result = ima_lsm_update_rule(entry);
 486                 if (result) {
 487                         pr_err("lsm rule update error %d\n", result);
 488                         return;
 489                 }
 490         }
 491 }
 492
 493 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 494                           void *lsm_data)
 495 {
 496         if (event != LSM_POLICY_CHANGE)
 497                 return NOTIFY_DONE;
 498
 499         ima_lsm_update_rules();
 500         return NOTIFY_OK;
 501 }
 502
 503 /**
 504  * ima_match_rule_data - determine whether func_data matches the policy rule
 505  * @rule: a pointer to a rule
 506  * @func_data: data to match against the measure rule data
 507  * @cred: a pointer to a credentials structure for user validation
 508  *
 509  * Returns true if func_data matches one in the rule, false otherwise.
 510  */
 511 static bool ima_match_rule_data(struct ima_rule_entry *rule,
 512                                 const char *func_data,
 513                                 const struct cred *cred)
 514 {
 515         const struct ima_rule_opt_list *opt_list = NULL;
 516         bool matched = false;
 517         size_t i;
 518
 519         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 520                 return false;
 521
 522         switch (rule->func) {
 523         case KEY_CHECK:
 524                 if (!rule->keyrings)
 525                         return true;
 526
 527                 opt_list = rule->keyrings;
 528                 break;
 529         case CRITICAL_DATA:
 530                 if (!rule->label)
 531                         return true;
 532
 533                 opt_list = rule->label;
 534                 break;
 535         default:
 536                 return false;
 537         }
 538
 539         if (!func_data)
 540                 return false;
 541
 542         for (i = 0; i < opt_list->count; i++) {
 543                 if (!strcmp(opt_list->items[i], func_data)) {
 544                         matched = true;
 545                         break;
 546                 }
 547         }
 548
 549         return matched;
 550 }
 551
 552 /**
 553  * ima_match_rules - determine whether an inode matches the policy rule.
 554  * @rule: a pointer to a rule
 555  * @idmap: idmap of the mount the inode was found from
 556  * @inode: a pointer to an inode
 557  * @cred: a pointer to a credentials structure for user validation
 558  * @secid: the secid of the task to be validated
 559  * @func: LIM hook identifier
 560  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 561  * @func_data: func specific data, may be NULL
 562  *
 563  * Returns true on rule match, false on failure.
 564  */
 565 static bool ima_match_rules(struct ima_rule_entry *rule,
 566                             struct mnt_idmap *idmap,
 567                             struct inode *inode, const struct cred *cred,
 568                             u32 secid, enum ima_hooks func, int mask,
 569                             const char *func_data)
 570 {
 571         int i;
 572         bool result = false;
 573         struct ima_rule_entry *lsm_rule = rule;
 574         bool rule_reinitialized = false;
 575
 576         if ((rule->flags & IMA_FUNC) &&
 577             (rule->func != func && func != POST_SETATTR))
 578                 return false;
 579
 580         switch (func) {
 581         case KEY_CHECK:
 582         case CRITICAL_DATA:
 583                 return ((rule->func == func) &&
 584                         ima_match_rule_data(rule, func_data, cred));
 585         default:
 586                 break;
 587         }
 588
 589         if ((rule->flags & IMA_MASK) &&
 590             (rule->mask != mask && func != POST_SETATTR))
 591                 return false;
 592         if ((rule->flags & IMA_INMASK) &&
 593             (!(rule->mask & mask) && func != POST_SETATTR))
 594                 return false;
 595         if ((rule->flags & IMA_FSMAGIC)
 596             && rule->fsmagic != inode->i_sb->s_magic)
 597                 return false;
 598         if ((rule->flags & IMA_FSNAME)
 599             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 600                 return false;
 601         if ((rule->flags & IMA_FSUUID) &&
 602             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 603                 return false;
 604         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 605                 return false;
 606         if (rule->flags & IMA_EUID) {
 607                 if (has_capability_noaudit(current, CAP_SETUID)) {
 608                         if (!rule->uid_op(cred->euid, rule->uid)
 609                             && !rule->uid_op(cred->suid, rule->uid)
 610                             && !rule->uid_op(cred->uid, rule->uid))
 611                                 return false;
 612                 } else if (!rule->uid_op(cred->euid, rule->uid))
 613                         return false;
 614         }
 615         if ((rule->flags & IMA_GID) && !rule->gid_op(cred->gid, rule->gid))
 616                 return false;
 617         if (rule->flags & IMA_EGID) {
 618                 if (has_capability_noaudit(current, CAP_SETGID)) {
 619                         if (!rule->gid_op(cred->egid, rule->gid)
 620                             && !rule->gid_op(cred->sgid, rule->gid)
 621                             && !rule->gid_op(cred->gid, rule->gid))
 622                                 return false;
 623                 } else if (!rule->gid_op(cred->egid, rule->gid))
 624                         return false;
 625         }
 626         if ((rule->flags & IMA_FOWNER) &&
 627             !rule->fowner_op(i_uid_into_vfsuid(idmap, inode),
 628                              rule->fowner))
 629                 return false;
 630         if ((rule->flags & IMA_FGROUP) &&
 631             !rule->fgroup_op(i_gid_into_vfsgid(idmap, inode),
 632                              rule->fgroup))
 633                 return false;
 634         for (i = 0; i < MAX_LSM_RULES; i++) {
 635                 int rc = 0;
 636                 u32 osid;
 637
 638                 if (!lsm_rule->lsm[i].rule) {
 639                         if (!lsm_rule->lsm[i].args_p)
 640                                 continue;
 641                         else
 642                                 return false;
 643                 }
 644
 645 retry:
 646                 switch (i) {
 647                 case LSM_OBJ_USER:
 648                 case LSM_OBJ_ROLE:
 649                 case LSM_OBJ_TYPE:
 650                         security_inode_getsecid(inode, &osid);
 651                         rc = ima_filter_rule_match(osid, lsm_rule->lsm[i].type,
 652                                                    Audit_equal,
 653                                                    lsm_rule->lsm[i].rule);
 654                         break;
 655                 case LSM_SUBJ_USER:
 656                 case LSM_SUBJ_ROLE:
 657                 case LSM_SUBJ_TYPE:
 658                         rc = ima_filter_rule_match(secid, lsm_rule->lsm[i].type,
 659                                                    Audit_equal,
 660                                                    lsm_rule->lsm[i].rule);
 661                         break;
 662                 default:
 663                         break;
 664                 }
 665
 666                 if (rc == -ESTALE && !rule_reinitialized) {
 667                         lsm_rule = ima_lsm_copy_rule(rule);
 668                         if (lsm_rule) {
 669                                 rule_reinitialized = true;
 670                                 goto retry;
 671                         }
 672                 }
 673                 if (!rc) {
 674                         result = false;
 675                         goto out;
 676                 }
 677         }
 678         result = true;
 679
 680 out:
 681         if (rule_reinitialized) {
 682                 for (i = 0; i < MAX_LSM_RULES; i++)
 683                         ima_filter_rule_free(lsm_rule->lsm[i].rule);
 684                 kfree(lsm_rule);
 685         }
 686         return result;
 687 }
 688
 689 /*
 690  * In addition to knowing that we need to appraise the file in general,
 691  * we need to differentiate between calling hooks, for hook specific rules.
 692  */
 693 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 694 {
 695         if (!(rule->flags & IMA_FUNC))
 696                 return IMA_FILE_APPRAISE;
 697
 698         switch (func) {
 699         case MMAP_CHECK:
 700         case MMAP_CHECK_REQPROT:
 701                 return IMA_MMAP_APPRAISE;
 702         case BPRM_CHECK:
 703                 return IMA_BPRM_APPRAISE;
 704         case CREDS_CHECK:
 705                 return IMA_CREDS_APPRAISE;
 706         case FILE_CHECK:
 707         case POST_SETATTR:
 708                 return IMA_FILE_APPRAISE;
 709         case MODULE_CHECK ... MAX_CHECK - 1:
 710         default:
 711                 return IMA_READ_APPRAISE;
 712         }
 713 }
 714
 715 /**
 716  * ima_match_policy - decision based on LSM and other conditions
 717  * @idmap: idmap of the mount the inode was found from
 718  * @inode: pointer to an inode for which the policy decision is being made
 719  * @cred: pointer to a credentials structure for which the policy decision is
 720  *        being made
 721  * @secid: LSM secid of the task to be validated
 722  * @func: IMA hook identifier
 723  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 724  * @pcr: set the pcr to extend
 725  * @template_desc: the template that should be used for this rule
 726  * @func_data: func specific data, may be NULL
 727  * @allowed_algos: allowlist of hash algorithms for the IMA xattr
 728  *
 729  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 730  * conditions.
 731  *
 732  * Since the IMA policy may be updated multiple times we need to lock the
 733  * list when walking it.  Reads are many orders of magnitude more numerous
 734  * than writes so ima_match_policy() is classical RCU candidate.
 735  */
 736 int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
 737                      const struct cred *cred, u32 secid, enum ima_hooks func,
 738                      int mask, int flags, int *pcr,
 739                      struct ima_template_desc **template_desc,
 740                      const char *func_data, unsigned int *allowed_algos)
 741 {
 742         struct ima_rule_entry *entry;
 743         int action = 0, actmask = flags | (flags << 1);
 744         struct list_head *ima_rules_tmp;
 745
 746         if (template_desc && !*template_desc)
 747                 *template_desc = ima_template_desc_current();
 748
 749         rcu_read_lock();
 750         ima_rules_tmp = rcu_dereference(ima_rules);
 751         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 752
 753                 if (!(entry->action & actmask))
 754                         continue;
 755
 756                 if (!ima_match_rules(entry, idmap, inode, cred, secid,
 757                                      func, mask, func_data))
 758                         continue;
 759
 760                 action |= entry->flags & IMA_NONACTION_FLAGS;
 761
 762                 action |= entry->action & IMA_DO_MASK;
 763                 if (entry->action & IMA_APPRAISE) {
 764                         action |= get_subaction(entry, func);
 765                         action &= ~IMA_HASH;
 766                         if (ima_fail_unverifiable_sigs)
 767                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 768
 769                         if (allowed_algos &&
 770                             entry->flags & IMA_VALIDATE_ALGOS)
 771                                 *allowed_algos = entry->allowed_algos;
 772                 }
 773
 774                 if (entry->action & IMA_DO_MASK)
 775                         actmask &= ~(entry->action | entry->action << 1);
 776                 else
 777                         actmask &= ~(entry->action | entry->action >> 1);
 778
 779                 if ((pcr) && (entry->flags & IMA_PCR))
 780                         *pcr = entry->pcr;
 781
 782                 if (template_desc && entry->template)
 783                         *template_desc = entry->template;
 784
 785                 if (!actmask)
 786                         break;
 787         }
 788         rcu_read_unlock();
 789
 790         return action;
 791 }
 792
 793 /**
 794  * ima_update_policy_flags() - Update global IMA variables
 795  *
 796  * Update ima_policy_flag and ima_setxattr_allowed_hash_algorithms
 797  * based on the currently loaded policy.
 798  *
 799  * With ima_policy_flag, the decision to short circuit out of a function
 800  * or not call the function in the first place can be made earlier.
 801  *
 802  * With ima_setxattr_allowed_hash_algorithms, the policy can restrict the
 803  * set of hash algorithms accepted when updating the security.ima xattr of
 804  * a file.
 805  *
 806  * Context: called after a policy update and at system initialization.
 807  */
 808 void ima_update_policy_flags(void)
 809 {
 810         struct ima_rule_entry *entry;
 811         int new_policy_flag = 0;
 812         struct list_head *ima_rules_tmp;
 813
 814         rcu_read_lock();
 815         ima_rules_tmp = rcu_dereference(ima_rules);
 816         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
 817                 /*
 818                  * SETXATTR_CHECK rules do not implement a full policy check
 819                  * because rule checking would probably have an important
 820                  * performance impact on setxattr(). As a consequence, only one
 821                  * SETXATTR_CHECK can be active at a given time.
 822                  * Because we want to preserve that property, we set out to use
 823                  * atomic_cmpxchg. Either:
 824                  * - the atomic was non-zero: a setxattr hash policy is
 825                  *   already enforced, we do nothing
 826                  * - the atomic was zero: no setxattr policy was set, enable
 827                  *   the setxattr hash policy
 828                  */
 829                 if (entry->func == SETXATTR_CHECK) {
 830                         atomic_cmpxchg(&ima_setxattr_allowed_hash_algorithms,
 831                                        0, entry->allowed_algos);
 832                         /* SETXATTR_CHECK doesn't impact ima_policy_flag */
 833                         continue;
 834                 }
 835
 836                 if (entry->action & IMA_DO_MASK)
 837                         new_policy_flag |= entry->action;
 838         }
 839         rcu_read_unlock();
 840
 841         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 842         if (!ima_appraise)
 843                 new_policy_flag &= ~IMA_APPRAISE;
 844
 845         ima_policy_flag = new_policy_flag;
 846 }
 847
 848 static int ima_appraise_flag(enum ima_hooks func)
 849 {
 850         if (func == MODULE_CHECK)
 851                 return IMA_APPRAISE_MODULES;
 852         else if (func == FIRMWARE_CHECK)
 853                 return IMA_APPRAISE_FIRMWARE;
 854         else if (func == POLICY_CHECK)
 855                 return IMA_APPRAISE_POLICY;
 856         else if (func == KEXEC_KERNEL_CHECK)
 857                 return IMA_APPRAISE_KEXEC;
 858         return 0;
 859 }
 860
 861 static void add_rules(struct ima_rule_entry *entries, int count,
 862                       enum policy_rule_list policy_rule)
 863 {
 864         int i = 0;
 865
 866         for (i = 0; i < count; i++) {
 867                 struct ima_rule_entry *entry;
 868
 869                 if (policy_rule & IMA_DEFAULT_POLICY)
 870                         list_add_tail(&entries[i].list, &ima_default_rules);
 871
 872                 if (policy_rule & IMA_CUSTOM_POLICY) {
 873                         entry = kmemdup(&entries[i], sizeof(*entry),
 874                                         GFP_KERNEL);
 875                         if (!entry)
 876                                 continue;
 877
 878                         list_add_tail(&entry->list, &ima_policy_rules);
 879                 }
 880                 if (entries[i].action == APPRAISE) {
 881                         if (entries != build_appraise_rules)
 882                                 temp_ima_appraise |=
 883                                         ima_appraise_flag(entries[i].func);
 884                         else
 885                                 build_ima_appraise |=
 886                                         ima_appraise_flag(entries[i].func);
 887                 }
 888         }
 889 }
 890
 891 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 892
 893 static int __init ima_init_arch_policy(void)
 894 {
 895         const char * const *arch_rules;
 896         const char * const *rules;
 897         int arch_entries = 0;
 898         int i = 0;
 899
 900         arch_rules = arch_get_ima_policy();
 901         if (!arch_rules)
 902                 return arch_entries;
 903
 904         /* Get number of rules */
 905         for (rules = arch_rules; *rules != NULL; rules++)
 906                 arch_entries++;
 907
 908         arch_policy_entry = kcalloc(arch_entries + 1,
 909                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 910         if (!arch_policy_entry)
 911                 return 0;
 912
 913         /* Convert each policy string rules to struct ima_rule_entry format */
 914         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 915                 char rule[255];
 916                 int result;
 917
 918                 result = strscpy(rule, *rules, sizeof(rule));
 919
 920                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 921                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 922                 if (result) {
 923                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 924                                 rule);
 925                         memset(&arch_policy_entry[i], 0,
 926                                sizeof(*arch_policy_entry));
 927                         continue;
 928                 }
 929                 i++;
 930         }
 931         return i;
 932 }
 933
 934 /**
 935  * ima_init_policy - initialize the default measure rules.
 936  *
 937  * ima_rules points to either the ima_default_rules or the new ima_policy_rules.
 938  */
 939 void __init ima_init_policy(void)
 940 {
 941         int build_appraise_entries, arch_entries;
 942
 943         /* if !ima_policy, we load NO default rules */
 944         if (ima_policy)
 945                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 946                           IMA_DEFAULT_POLICY);
 947
 948         switch (ima_policy) {
 949         case ORIGINAL_TCB:
 950                 add_rules(original_measurement_rules,
 951                           ARRAY_SIZE(original_measurement_rules),
 952                           IMA_DEFAULT_POLICY);
 953                 break;
 954         case DEFAULT_TCB:
 955                 add_rules(default_measurement_rules,
 956                           ARRAY_SIZE(default_measurement_rules),
 957                           IMA_DEFAULT_POLICY);
 958                 break;
 959         default:
 960                 break;
 961         }
 962
 963         /*
 964          * Based on runtime secure boot flags, insert arch specific measurement
 965          * and appraise rules requiring file signatures for both the initial
 966          * and custom policies, prior to other appraise rules.
 967          * (Highest priority)
 968          */
 969         arch_entries = ima_init_arch_policy();
 970         if (!arch_entries)
 971                 pr_info("No architecture policies found\n");
 972         else
 973                 add_rules(arch_policy_entry, arch_entries,
 974                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 975
 976         /*
 977          * Insert the builtin "secure_boot" policy rules requiring file
 978          * signatures, prior to other appraise rules.
 979          */
 980         if (ima_use_secure_boot)
 981                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 982                           IMA_DEFAULT_POLICY);
 983
 984         /*
 985          * Insert the build time appraise rules requiring file signatures
 986          * for both the initial and custom policies, prior to other appraise
 987          * rules. As the secure boot rules includes all of the build time
 988          * rules, include either one or the other set of rules, but not both.
 989          */
 990         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 991         if (build_appraise_entries) {
 992                 if (ima_use_secure_boot)
 993                         add_rules(build_appraise_rules, build_appraise_entries,
 994                                   IMA_CUSTOM_POLICY);
 995                 else
 996                         add_rules(build_appraise_rules, build_appraise_entries,
 997                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 998         }
 999
1000         if (ima_use_appraise_tcb)
1001                 add_rules(default_appraise_rules,
1002                           ARRAY_SIZE(default_appraise_rules),
1003                           IMA_DEFAULT_POLICY);
1004
1005         if (ima_use_critical_data)
1006                 add_rules(critical_data_rules,
1007                           ARRAY_SIZE(critical_data_rules),
1008                           IMA_DEFAULT_POLICY);
1009
1010         atomic_set(&ima_setxattr_allowed_hash_algorithms, 0);
1011
1012         ima_update_policy_flags();
1013 }
1014
1015 /* Make sure we have a valid policy, at least containing some rules. */
1016 int ima_check_policy(void)
1017 {
1018         if (list_empty(&ima_temp_rules))
1019                 return -EINVAL;
1020         return 0;
1021 }
1022
1023 /**
1024  * ima_update_policy - update default_rules with new measure rules
1025  *
1026  * Called on file .release to update the default rules with a complete new
1027  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
1028  * they make a queue.  The policy may be updated multiple times and this is the
1029  * RCU updater.
1030  *
1031  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
1032  * we switch from the default policy to user defined.
1033  */
1034 void ima_update_policy(void)
1035 {
1036         struct list_head *policy = &ima_policy_rules;
1037
1038         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
1039
1040         if (ima_rules != (struct list_head __rcu *)policy) {
1041                 ima_policy_flag = 0;
1042
1043                 rcu_assign_pointer(ima_rules, policy);
1044                 /*
1045                  * IMA architecture specific policy rules are specified
1046                  * as strings and converted to an array of ima_entry_rules
1047                  * on boot.  After loading a custom policy, free the
1048                  * architecture specific rules stored as an array.
1049                  */
1050                 kfree(arch_policy_entry);
1051         }
1052         ima_update_policy_flags();
1053
1054         /* Custom IMA policy has been loaded */
1055         ima_process_queued_keys();
1056 }
1057
1058 /* Keep the enumeration in sync with the policy_tokens! */
1059 enum policy_opt {
1060         Opt_measure, Opt_dont_measure,
1061         Opt_appraise, Opt_dont_appraise,
1062         Opt_audit, Opt_hash, Opt_dont_hash,
1063         Opt_obj_user, Opt_obj_role, Opt_obj_type,
1064         Opt_subj_user, Opt_subj_role, Opt_subj_type,
1065         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname, Opt_fsuuid,
1066         Opt_uid_eq, Opt_euid_eq, Opt_gid_eq, Opt_egid_eq,
1067         Opt_fowner_eq, Opt_fgroup_eq,
1068         Opt_uid_gt, Opt_euid_gt, Opt_gid_gt, Opt_egid_gt,
1069         Opt_fowner_gt, Opt_fgroup_gt,
1070         Opt_uid_lt, Opt_euid_lt, Opt_gid_lt, Opt_egid_lt,
1071         Opt_fowner_lt, Opt_fgroup_lt,
1072         Opt_digest_type,
1073         Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos,
1074         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
1075         Opt_label, Opt_err
1076 };
1077
1078 static const match_table_t policy_tokens = {
1079         {Opt_measure, "measure"},
1080         {Opt_dont_measure, "dont_measure"},
1081         {Opt_appraise, "appraise"},
1082         {Opt_dont_appraise, "dont_appraise"},
1083         {Opt_audit, "audit"},
1084         {Opt_hash, "hash"},
1085         {Opt_dont_hash, "dont_hash"},
1086         {Opt_obj_user, "obj_user=%s"},
1087         {Opt_obj_role, "obj_role=%s"},
1088         {Opt_obj_type, "obj_type=%s"},
1089         {Opt_subj_user, "subj_user=%s"},
1090         {Opt_subj_role, "subj_role=%s"},
1091         {Opt_subj_type, "subj_type=%s"},
1092         {Opt_func, "func=%s"},
1093         {Opt_mask, "mask=%s"},
1094         {Opt_fsmagic, "fsmagic=%s"},
1095         {Opt_fsname, "fsname=%s"},
1096         {Opt_fsuuid, "fsuuid=%s"},
1097         {Opt_uid_eq, "uid=%s"},
1098         {Opt_euid_eq, "euid=%s"},
1099         {Opt_gid_eq, "gid=%s"},
1100         {Opt_egid_eq, "egid=%s"},
1101         {Opt_fowner_eq, "fowner=%s"},
1102         {Opt_fgroup_eq, "fgroup=%s"},
1103         {Opt_uid_gt, "uid>%s"},
1104         {Opt_euid_gt, "euid>%s"},
1105         {Opt_gid_gt, "gid>%s"},
1106         {Opt_egid_gt, "egid>%s"},
1107         {Opt_fowner_gt, "fowner>%s"},
1108         {Opt_fgroup_gt, "fgroup>%s"},
1109         {Opt_uid_lt, "uid<%s"},
1110         {Opt_euid_lt, "euid<%s"},
1111         {Opt_gid_lt, "gid<%s"},
1112         {Opt_egid_lt, "egid<%s"},
1113         {Opt_fowner_lt, "fowner<%s"},
1114         {Opt_fgroup_lt, "fgroup<%s"},
1115         {Opt_digest_type, "digest_type=%s"},
1116         {Opt_appraise_type, "appraise_type=%s"},
1117         {Opt_appraise_flag, "appraise_flag=%s"},
1118         {Opt_appraise_algos, "appraise_algos=%s"},
1119         {Opt_permit_directio, "permit_directio"},
1120         {Opt_pcr, "pcr=%s"},
1121         {Opt_template, "template=%s"},
1122         {Opt_keyrings, "keyrings=%s"},
1123         {Opt_label, "label=%s"},
1124         {Opt_err, NULL}
1125 };
1126
1127 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
1128                              substring_t *args, int lsm_rule, int audit_type)
1129 {
1130         int result;
1131
1132         if (entry->lsm[lsm_rule].rule)
1133                 return -EINVAL;
1134
1135         entry->lsm[lsm_rule].args_p = match_strdup(args);
1136         if (!entry->lsm[lsm_rule].args_p)
1137                 return -ENOMEM;
1138
1139         entry->lsm[lsm_rule].type = audit_type;
1140         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1141                                       entry->lsm[lsm_rule].args_p,
1142                                       &entry->lsm[lsm_rule].rule);
1143         if (!entry->lsm[lsm_rule].rule) {
1144                 pr_warn("rule for LSM \'%s\' is undefined\n",
1145                         entry->lsm[lsm_rule].args_p);
1146
1147                 if (ima_rules == (struct list_head __rcu *)(&ima_default_rules)) {
1148                         kfree(entry->lsm[lsm_rule].args_p);
1149                         entry->lsm[lsm_rule].args_p = NULL;
1150                         result = -EINVAL;
1151                 } else
1152                         result = 0;
1153         }
1154
1155         return result;
1156 }
1157
1158 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1159                               enum policy_opt rule_operator)
1160 {
1161         if (!ab)
1162                 return;
1163
1164         switch (rule_operator) {
1165         case Opt_uid_gt:
1166         case Opt_euid_gt:
1167         case Opt_gid_gt:
1168         case Opt_egid_gt:
1169         case Opt_fowner_gt:
1170         case Opt_fgroup_gt:
1171                 audit_log_format(ab, "%s>", key);
1172                 break;
1173         case Opt_uid_lt:
1174         case Opt_euid_lt:
1175         case Opt_gid_lt:
1176         case Opt_egid_lt:
1177         case Opt_fowner_lt:
1178         case Opt_fgroup_lt:
1179                 audit_log_format(ab, "%s<", key);
1180                 break;
1181         default:
1182                 audit_log_format(ab, "%s=", key);
1183         }
1184         audit_log_format(ab, "%s ", value);
1185 }
1186 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1187 {
1188         ima_log_string_op(ab, key, value, Opt_err);
1189 }
1190
1191 /*
1192  * Validating the appended signature included in the measurement list requires
1193  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1194  * field). Therefore, notify the user if they have the 'modsig' field but not
1195  * the 'd-modsig' field in the template.
1196  */
1197 static void check_template_modsig(const struct ima_template_desc *template)
1198 {
1199 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1200         bool has_modsig, has_dmodsig;
1201         static bool checked;
1202         int i;
1203
1204         /* We only need to notify the user once. */
1205         if (checked)
1206                 return;
1207
1208         has_modsig = has_dmodsig = false;
1209         for (i = 0; i < template->num_fields; i++) {
1210                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1211                         has_modsig = true;
1212                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1213                         has_dmodsig = true;
1214         }
1215
1216         if (has_modsig && !has_dmodsig)
1217                 pr_notice(MSG);
1218
1219         checked = true;
1220 #undef MSG
1221 }
1222
1223 /*
1224  * Warn if the template does not contain the given field.
1225  */
1226 static void check_template_field(const struct ima_template_desc *template,
1227                                  const char *field, const char *msg)
1228 {
1229         int i;
1230
1231         for (i = 0; i < template->num_fields; i++)
1232                 if (!strcmp(template->fields[i]->field_id, field))
1233                         return;
1234
1235         pr_notice_once("%s", msg);
1236 }
1237
1238 static bool ima_validate_rule(struct ima_rule_entry *entry)
1239 {
1240         /* Ensure that the action is set and is compatible with the flags */
1241         if (entry->action == UNKNOWN)
1242                 return false;
1243
1244         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1245                 return false;
1246
1247         if (entry->action != APPRAISE &&
1248             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED |
1249                             IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1250                 return false;
1251
1252         /*
1253          * The IMA_FUNC bit must be set if and only if there's a valid hook
1254          * function specified, and vice versa. Enforcing this property allows
1255          * for the NONE case below to validate a rule without an explicit hook
1256          * function.
1257          */
1258         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1259             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1260                 return false;
1261
1262         /*
1263          * Ensure that the hook function is compatible with the other
1264          * components of the rule
1265          */
1266         switch (entry->func) {
1267         case NONE:
1268         case FILE_CHECK:
1269         case MMAP_CHECK:
1270         case MMAP_CHECK_REQPROT:
1271         case BPRM_CHECK:
1272         case CREDS_CHECK:
1273         case POST_SETATTR:
1274         case FIRMWARE_CHECK:
1275         case POLICY_CHECK:
1276                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1277                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1278                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1279                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1280                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1281                                      IMA_PERMIT_DIRECTIO | IMA_VALIDATE_ALGOS |
1282                                      IMA_VERITY_REQUIRED))
1283                         return false;
1284
1285                 break;
1286         case MODULE_CHECK:
1287         case KEXEC_KERNEL_CHECK:
1288         case KEXEC_INITRAMFS_CHECK:
1289                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1290                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1291                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1292                                      IMA_FSNAME | IMA_GID | IMA_EGID |
1293                                      IMA_FGROUP | IMA_DIGSIG_REQUIRED |
1294                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1295                                      IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
1296                         return false;
1297
1298                 break;
1299         case KEXEC_CMDLINE:
1300                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1301                         return false;
1302
1303                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1304                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1305                                      IMA_PCR | IMA_FSNAME | IMA_GID | IMA_EGID |
1306                                      IMA_FGROUP))
1307                         return false;
1308
1309                 break;
1310         case KEY_CHECK:
1311                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1312                         return false;
1313
1314                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1315                                      IMA_KEYRINGS))
1316                         return false;
1317
1318                 if (ima_rule_contains_lsm_cond(entry))
1319                         return false;
1320
1321                 break;
1322         case CRITICAL_DATA:
1323                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1324                         return false;
1325
1326                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_GID | IMA_PCR |
1327                                      IMA_LABEL))
1328                         return false;
1329
1330                 if (ima_rule_contains_lsm_cond(entry))
1331                         return false;
1332
1333                 break;
1334         case SETXATTR_CHECK:
1335                 /* any action other than APPRAISE is unsupported */
1336                 if (entry->action != APPRAISE)
1337                         return false;
1338
1339                 /* SETXATTR_CHECK requires an appraise_algos parameter */
1340                 if (!(entry->flags & IMA_VALIDATE_ALGOS))
1341                         return false;
1342
1343                 /*
1344                  * full policies are not supported, they would have too
1345                  * much of a performance impact
1346                  */
1347                 if (entry->flags & ~(IMA_FUNC | IMA_VALIDATE_ALGOS))
1348                         return false;
1349
1350                 break;
1351         default:
1352                 return false;
1353         }
1354
1355         /* Ensure that combinations of flags are compatible with each other */
1356         if (entry->flags & IMA_CHECK_BLACKLIST &&
1357             !(entry->flags & IMA_MODSIG_ALLOWED))
1358                 return false;
1359
1360         /*
1361          * Unlike for regular IMA 'appraise' policy rules where security.ima
1362          * xattr may contain either a file hash or signature, the security.ima
1363          * xattr for fsverity must contain a file signature (sigv3).  Ensure
1364          * that 'appraise' rules for fsverity require file signatures by
1365          * checking the IMA_DIGSIG_REQUIRED flag is set.
1366          */
1367         if (entry->action == APPRAISE &&
1368             (entry->flags & IMA_VERITY_REQUIRED) &&
1369             !(entry->flags & IMA_DIGSIG_REQUIRED))
1370                 return false;
1371
1372         return true;
1373 }
1374
1375 static unsigned int ima_parse_appraise_algos(char *arg)
1376 {
1377         unsigned int res = 0;
1378         int idx;
1379         char *token;
1380
1381         while ((token = strsep(&arg, ",")) != NULL) {
1382                 idx = match_string(hash_algo_name, HASH_ALGO__LAST, token);
1383
1384                 if (idx < 0) {
1385                         pr_err("unknown hash algorithm \"%s\"",
1386                                token);
1387                         return 0;
1388                 }
1389
1390                 if (!crypto_has_alg(hash_algo_name[idx], 0, 0)) {
1391                         pr_err("unavailable hash algorithm \"%s\", check your kernel configuration",
1392                                token);
1393                         return 0;
1394                 }
1395
1396                 /* Add the hash algorithm to the 'allowed' bitfield */
1397                 res |= (1U << idx);
1398         }
1399
1400         return res;
1401 }
1402
1403 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1404 {
1405         struct audit_buffer *ab;
1406         char *from;
1407         char *p;
1408         bool eid_token; /* either euid or egid */
1409         struct ima_template_desc *template_desc;
1410         int result = 0;
1411
1412         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1413                                        AUDIT_INTEGRITY_POLICY_RULE);
1414
1415         entry->uid = INVALID_UID;
1416         entry->gid = INVALID_GID;
1417         entry->fowner = INVALID_UID;
1418         entry->fgroup = INVALID_GID;
1419         entry->uid_op = &uid_eq;
1420         entry->gid_op = &gid_eq;
1421         entry->fowner_op = &vfsuid_eq_kuid;
1422         entry->fgroup_op = &vfsgid_eq_kgid;
1423         entry->action = UNKNOWN;
1424         while ((p = strsep(&rule, " \t")) != NULL) {
1425                 substring_t args[MAX_OPT_ARGS];
1426                 int token;
1427                 unsigned long lnum;
1428
1429                 if (result < 0)
1430                         break;
1431                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1432                         continue;
1433                 token = match_token(p, policy_tokens, args);
1434                 switch (token) {
1435                 case Opt_measure:
1436                         ima_log_string(ab, "action", "measure");
1437
1438                         if (entry->action != UNKNOWN)
1439                                 result = -EINVAL;
1440
1441                         entry->action = MEASURE;
1442                         break;
1443                 case Opt_dont_measure:
1444                         ima_log_string(ab, "action", "dont_measure");
1445
1446                         if (entry->action != UNKNOWN)
1447                                 result = -EINVAL;
1448
1449                         entry->action = DONT_MEASURE;
1450                         break;
1451                 case Opt_appraise:
1452                         ima_log_string(ab, "action", "appraise");
1453
1454                         if (entry->action != UNKNOWN)
1455                                 result = -EINVAL;
1456
1457                         entry->action = APPRAISE;
1458                         break;
1459                 case Opt_dont_appraise:
1460                         ima_log_string(ab, "action", "dont_appraise");
1461
1462                         if (entry->action != UNKNOWN)
1463                                 result = -EINVAL;
1464
1465                         entry->action = DONT_APPRAISE;
1466                         break;
1467                 case Opt_audit:
1468                         ima_log_string(ab, "action", "audit");
1469
1470                         if (entry->action != UNKNOWN)
1471                                 result = -EINVAL;
1472
1473                         entry->action = AUDIT;
1474                         break;
1475                 case Opt_hash:
1476                         ima_log_string(ab, "action", "hash");
1477
1478                         if (entry->action != UNKNOWN)
1479                                 result = -EINVAL;
1480
1481                         entry->action = HASH;
1482                         break;
1483                 case Opt_dont_hash:
1484                         ima_log_string(ab, "action", "dont_hash");
1485
1486                         if (entry->action != UNKNOWN)
1487                                 result = -EINVAL;
1488
1489                         entry->action = DONT_HASH;
1490                         break;
1491                 case Opt_func:
1492                         ima_log_string(ab, "func", args[0].from);
1493
1494                         if (entry->func)
1495                                 result = -EINVAL;
1496
1497                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1498                                 entry->func = FILE_CHECK;
1499                         /* PATH_CHECK is for backwards compat */
1500                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1501                                 entry->func = FILE_CHECK;
1502                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1503                                 entry->func = MODULE_CHECK;
1504                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1505                                 entry->func = FIRMWARE_CHECK;
1506                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1507                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1508                                 entry->func = MMAP_CHECK;
1509                         else if ((strcmp(args[0].from, "MMAP_CHECK_REQPROT") == 0))
1510                                 entry->func = MMAP_CHECK_REQPROT;
1511                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1512                                 entry->func = BPRM_CHECK;
1513                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1514                                 entry->func = CREDS_CHECK;
1515                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1516                                  0)
1517                                 entry->func = KEXEC_KERNEL_CHECK;
1518                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1519                                  == 0)
1520                                 entry->func = KEXEC_INITRAMFS_CHECK;
1521                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1522                                 entry->func = POLICY_CHECK;
1523                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1524                                 entry->func = KEXEC_CMDLINE;
1525                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1526                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1527                                 entry->func = KEY_CHECK;
1528                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1529                                 entry->func = CRITICAL_DATA;
1530                         else if (strcmp(args[0].from, "SETXATTR_CHECK") == 0)
1531                                 entry->func = SETXATTR_CHECK;
1532                         else
1533                                 result = -EINVAL;
1534                         if (!result)
1535                                 entry->flags |= IMA_FUNC;
1536                         break;
1537                 case Opt_mask:
1538                         ima_log_string(ab, "mask", args[0].from);
1539
1540                         if (entry->mask)
1541                                 result = -EINVAL;
1542
1543                         from = args[0].from;
1544                         if (*from == '^')
1545                                 from++;
1546
1547                         if ((strcmp(from, "MAY_EXEC")) == 0)
1548                                 entry->mask = MAY_EXEC;
1549                         else if (strcmp(from, "MAY_WRITE") == 0)
1550                                 entry->mask = MAY_WRITE;
1551                         else if (strcmp(from, "MAY_READ") == 0)
1552                                 entry->mask = MAY_READ;
1553                         else if (strcmp(from, "MAY_APPEND") == 0)
1554                                 entry->mask = MAY_APPEND;
1555                         else
1556                                 result = -EINVAL;
1557                         if (!result)
1558                                 entry->flags |= (*args[0].from == '^')
1559                                      ? IMA_INMASK : IMA_MASK;
1560                         break;
1561                 case Opt_fsmagic:
1562                         ima_log_string(ab, "fsmagic", args[0].from);
1563
1564                         if (entry->fsmagic) {
1565                                 result = -EINVAL;
1566                                 break;
1567                         }
1568
1569                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1570                         if (!result)
1571                                 entry->flags |= IMA_FSMAGIC;
1572                         break;
1573                 case Opt_fsname:
1574                         ima_log_string(ab, "fsname", args[0].from);
1575
1576                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1577                         if (!entry->fsname) {
1578                                 result = -ENOMEM;
1579                                 break;
1580                         }
1581                         result = 0;
1582                         entry->flags |= IMA_FSNAME;
1583                         break;
1584                 case Opt_keyrings:
1585                         ima_log_string(ab, "keyrings", args[0].from);
1586
1587                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1588                             entry->keyrings) {
1589                                 result = -EINVAL;
1590                                 break;
1591                         }
1592
1593                         entry->keyrings = ima_alloc_rule_opt_list(args);
1594                         if (IS_ERR(entry->keyrings)) {
1595                                 result = PTR_ERR(entry->keyrings);
1596                                 entry->keyrings = NULL;
1597                                 break;
1598                         }
1599
1600                         entry->flags |= IMA_KEYRINGS;
1601                         break;
1602                 case Opt_label:
1603                         ima_log_string(ab, "label", args[0].from);
1604
1605                         if (entry->label) {
1606                                 result = -EINVAL;
1607                                 break;
1608                         }
1609
1610                         entry->label = ima_alloc_rule_opt_list(args);
1611                         if (IS_ERR(entry->label)) {
1612                                 result = PTR_ERR(entry->label);
1613                                 entry->label = NULL;
1614                                 break;
1615                         }
1616
1617                         entry->flags |= IMA_LABEL;
1618                         break;
1619                 case Opt_fsuuid:
1620                         ima_log_string(ab, "fsuuid", args[0].from);
1621
1622                         if (!uuid_is_null(&entry->fsuuid)) {
1623                                 result = -EINVAL;
1624                                 break;
1625                         }
1626
1627                         result = uuid_parse(args[0].from, &entry->fsuuid);
1628                         if (!result)
1629                                 entry->flags |= IMA_FSUUID;
1630                         break;
1631                 case Opt_uid_gt:
1632                 case Opt_euid_gt:
1633                         entry->uid_op = &uid_gt;
1634                         fallthrough;
1635                 case Opt_uid_lt:
1636                 case Opt_euid_lt:
1637                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1638                                 entry->uid_op = &uid_lt;
1639                         fallthrough;
1640                 case Opt_uid_eq:
1641                 case Opt_euid_eq:
1642                         eid_token = (token == Opt_euid_eq) ||
1643                                     (token == Opt_euid_gt) ||
1644                                     (token == Opt_euid_lt);
1645
1646                         ima_log_string_op(ab, eid_token ? "euid" : "uid",
1647                                           args[0].from, token);
1648
1649                         if (uid_valid(entry->uid)) {
1650                                 result = -EINVAL;
1651                                 break;
1652                         }
1653
1654                         result = kstrtoul(args[0].from, 10, &lnum);
1655                         if (!result) {
1656                                 entry->uid = make_kuid(current_user_ns(),
1657                                                        (uid_t) lnum);
1658                                 if (!uid_valid(entry->uid) ||
1659                                     (uid_t)lnum != lnum)
1660                                         result = -EINVAL;
1661                                 else
1662                                         entry->flags |= eid_token
1663                                             ? IMA_EUID : IMA_UID;
1664                         }
1665                         break;
1666                 case Opt_gid_gt:
1667                 case Opt_egid_gt:
1668                         entry->gid_op = &gid_gt;
1669                         fallthrough;
1670                 case Opt_gid_lt:
1671                 case Opt_egid_lt:
1672                         if ((token == Opt_gid_lt) || (token == Opt_egid_lt))
1673                                 entry->gid_op = &gid_lt;
1674                         fallthrough;
1675                 case Opt_gid_eq:
1676                 case Opt_egid_eq:
1677                         eid_token = (token == Opt_egid_eq) ||
1678                                     (token == Opt_egid_gt) ||
1679                                     (token == Opt_egid_lt);
1680
1681                         ima_log_string_op(ab, eid_token ? "egid" : "gid",
1682                                           args[0].from, token);
1683
1684                         if (gid_valid(entry->gid)) {
1685                                 result = -EINVAL;
1686                                 break;
1687                         }
1688
1689                         result = kstrtoul(args[0].from, 10, &lnum);
1690                         if (!result) {
1691                                 entry->gid = make_kgid(current_user_ns(),
1692                                                        (gid_t)lnum);
1693                                 if (!gid_valid(entry->gid) ||
1694                                     (((gid_t)lnum) != lnum))
1695                                         result = -EINVAL;
1696                                 else
1697                                         entry->flags |= eid_token
1698                                             ? IMA_EGID : IMA_GID;
1699                         }
1700                         break;
1701                 case Opt_fowner_gt:
1702                         entry->fowner_op = &vfsuid_gt_kuid;
1703                         fallthrough;
1704                 case Opt_fowner_lt:
1705                         if (token == Opt_fowner_lt)
1706                                 entry->fowner_op = &vfsuid_lt_kuid;
1707                         fallthrough;
1708                 case Opt_fowner_eq:
1709                         ima_log_string_op(ab, "fowner", args[0].from, token);
1710
1711                         if (uid_valid(entry->fowner)) {
1712                                 result = -EINVAL;
1713                                 break;
1714                         }
1715
1716                         result = kstrtoul(args[0].from, 10, &lnum);
1717                         if (!result) {
1718                                 entry->fowner = make_kuid(current_user_ns(),
1719                                                           (uid_t)lnum);
1720                                 if (!uid_valid(entry->fowner) ||
1721                                     (((uid_t)lnum) != lnum))
1722                                         result = -EINVAL;
1723                                 else
1724                                         entry->flags |= IMA_FOWNER;
1725                         }
1726                         break;
1727                 case Opt_fgroup_gt:
1728                         entry->fgroup_op = &vfsgid_gt_kgid;
1729                         fallthrough;
1730                 case Opt_fgroup_lt:
1731                         if (token == Opt_fgroup_lt)
1732                                 entry->fgroup_op = &vfsgid_lt_kgid;
1733                         fallthrough;
1734                 case Opt_fgroup_eq:
1735                         ima_log_string_op(ab, "fgroup", args[0].from, token);
1736
1737                         if (gid_valid(entry->fgroup)) {
1738                                 result = -EINVAL;
1739                                 break;
1740                         }
1741
1742                         result = kstrtoul(args[0].from, 10, &lnum);
1743                         if (!result) {
1744                                 entry->fgroup = make_kgid(current_user_ns(),
1745                                                           (gid_t)lnum);
1746                                 if (!gid_valid(entry->fgroup) ||
1747                                     (((gid_t)lnum) != lnum))
1748                                         result = -EINVAL;
1749                                 else
1750                                         entry->flags |= IMA_FGROUP;
1751                         }
1752                         break;
1753                 case Opt_obj_user:
1754                         ima_log_string(ab, "obj_user", args[0].from);
1755                         result = ima_lsm_rule_init(entry, args,
1756                                                    LSM_OBJ_USER,
1757                                                    AUDIT_OBJ_USER);
1758                         break;
1759                 case Opt_obj_role:
1760                         ima_log_string(ab, "obj_role", args[0].from);
1761                         result = ima_lsm_rule_init(entry, args,
1762                                                    LSM_OBJ_ROLE,
1763                                                    AUDIT_OBJ_ROLE);
1764                         break;
1765                 case Opt_obj_type:
1766                         ima_log_string(ab, "obj_type", args[0].from);
1767                         result = ima_lsm_rule_init(entry, args,
1768                                                    LSM_OBJ_TYPE,
1769                                                    AUDIT_OBJ_TYPE);
1770                         break;
1771                 case Opt_subj_user:
1772                         ima_log_string(ab, "subj_user", args[0].from);
1773                         result = ima_lsm_rule_init(entry, args,
1774                                                    LSM_SUBJ_USER,
1775                                                    AUDIT_SUBJ_USER);
1776                         break;
1777                 case Opt_subj_role:
1778                         ima_log_string(ab, "subj_role", args[0].from);
1779                         result = ima_lsm_rule_init(entry, args,
1780                                                    LSM_SUBJ_ROLE,
1781                                                    AUDIT_SUBJ_ROLE);
1782                         break;
1783                 case Opt_subj_type:
1784                         ima_log_string(ab, "subj_type", args[0].from);
1785                         result = ima_lsm_rule_init(entry, args,
1786                                                    LSM_SUBJ_TYPE,
1787                                                    AUDIT_SUBJ_TYPE);
1788                         break;
1789                 case Opt_digest_type:
1790                         ima_log_string(ab, "digest_type", args[0].from);
1791                         if (entry->flags & IMA_DIGSIG_REQUIRED)
1792                                 result = -EINVAL;
1793                         else if ((strcmp(args[0].from, "verity")) == 0)
1794                                 entry->flags |= IMA_VERITY_REQUIRED;
1795                         else
1796                                 result = -EINVAL;
1797                         break;
1798                 case Opt_appraise_type:
1799                         ima_log_string(ab, "appraise_type", args[0].from);
1800
1801                         if ((strcmp(args[0].from, "imasig")) == 0) {
1802                                 if (entry->flags & IMA_VERITY_REQUIRED)
1803                                         result = -EINVAL;
1804                                 else
1805                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1806                         } else if (strcmp(args[0].from, "sigv3") == 0) {
1807                                 /* Only fsverity supports sigv3 for now */
1808                                 if (entry->flags & IMA_VERITY_REQUIRED)
1809                                         entry->flags |= IMA_DIGSIG_REQUIRED;
1810                                 else
1811                                         result = -EINVAL;
1812                         } else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1813                                  strcmp(args[0].from, "imasig|modsig") == 0) {
1814                                 if (entry->flags & IMA_VERITY_REQUIRED)
1815                                         result = -EINVAL;
1816                                 else
1817                                         entry->flags |= IMA_DIGSIG_REQUIRED |
1818                                                 IMA_MODSIG_ALLOWED;
1819                         } else {
1820                                 result = -EINVAL;
1821                         }
1822                         break;
1823                 case Opt_appraise_flag:
1824                         ima_log_string(ab, "appraise_flag", args[0].from);
1825                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1826                             strstr(args[0].from, "blacklist"))
1827                                 entry->flags |= IMA_CHECK_BLACKLIST;
1828                         else
1829                                 result = -EINVAL;
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_CHECK_BLACKLIST)
2274                 seq_puts(m, "appraise_flag=check_blacklist ");
2275         if (entry->flags & IMA_PERMIT_DIRECTIO)
2276                 seq_puts(m, "permit_directio ");
2277         rcu_read_unlock();
2278         seq_puts(m, "\n");
2279         return 0;
2280 }
2281 #endif  /* CONFIG_IMA_READ_POLICY */
2282
2283 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
2284 /*
2285  * ima_appraise_signature: whether IMA will appraise a given function using
2286  * an IMA digital signature. This is restricted to cases where the kernel
2287  * has a set of built-in trusted keys in order to avoid an attacker simply
2288  * loading additional keys.
2289  */
2290 bool ima_appraise_signature(enum kernel_read_file_id id)
2291 {
2292         struct ima_rule_entry *entry;
2293         bool found = false;
2294         enum ima_hooks func;
2295         struct list_head *ima_rules_tmp;
2296
2297         if (id >= READING_MAX_ID)
2298                 return false;
2299
2300         if (id == READING_KEXEC_IMAGE && !(ima_appraise & IMA_APPRAISE_ENFORCE)
2301             && security_locked_down(LOCKDOWN_KEXEC))
2302                 return false;
2303
2304         func = read_idmap[id] ?: FILE_CHECK;
2305
2306         rcu_read_lock();
2307         ima_rules_tmp = rcu_dereference(ima_rules);
2308         list_for_each_entry_rcu(entry, ima_rules_tmp, list) {
2309                 if (entry->action != APPRAISE)
2310                         continue;
2311
2312                 /*
2313                  * A generic entry will match, but otherwise require that it
2314                  * match the func we're looking for
2315                  */
2316                 if (entry->func && entry->func != func)
2317                         continue;
2318
2319                 /*
2320                  * We require this to be a digital signature, not a raw IMA
2321                  * hash.
2322                  */
2323                 if (entry->flags & IMA_DIGSIG_REQUIRED)
2324                         found = true;
2325
2326                 /*
2327                  * We've found a rule that matches, so break now even if it
2328                  * didn't require a digital signature - a later rule that does
2329                  * won't override it, so would be a false positive.
2330                  */
2331                 break;
2332         }
2333
2334         rcu_read_unlock();
2335         return found;
2336 }
2337 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */