security/integrity/ima/ima_policy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 IBM Corporation
   4  * Author: Mimi Zohar <zohar@us.ibm.com>
   5  *
   6  * ima_policy.c
   7  *      - initialize default measure policy rules
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/list.h>
  12 #include <linux/kernel_read_file.h>
  13 #include <linux/fs.h>
  14 #include <linux/security.h>
  15 #include <linux/magic.h>
  16 #include <linux/parser.h>
  17 #include <linux/slab.h>
  18 #include <linux/rculist.h>
  19 #include <linux/genhd.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/ima.h>
  22
  23 #include "ima.h"
  24
  25 /* flags definitions */
  26 #define IMA_FUNC        0x0001
  27 #define IMA_MASK        0x0002
  28 #define IMA_FSMAGIC     0x0004
  29 #define IMA_UID         0x0008
  30 #define IMA_FOWNER      0x0010
  31 #define IMA_FSUUID      0x0020
  32 #define IMA_INMASK      0x0040
  33 #define IMA_EUID        0x0080
  34 #define IMA_PCR         0x0100
  35 #define IMA_FSNAME      0x0200
  36 #define IMA_KEYRINGS    0x0400
  37 #define IMA_LABEL       0x0800
  38
  39 #define UNKNOWN         0
  40 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  41 #define DONT_MEASURE    0x0002
  42 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  43 #define DONT_APPRAISE   0x0008
  44 #define AUDIT           0x0040
  45 #define HASH            0x0100
  46 #define DONT_HASH       0x0200
  47
  48 #define INVALID_PCR(a) (((a) < 0) || \
  49         (a) >= (sizeof_field(struct integrity_iint_cache, measured_pcrs) * 8))
  50
  51 int ima_policy_flag;
  52 static int temp_ima_appraise;
  53 static int build_ima_appraise __ro_after_init;
  54
  55 #define MAX_LSM_RULES 6
  56 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  57         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  58 };
  59
  60 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  61
  62 enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
  63
  64 struct ima_rule_opt_list {
  65         size_t count;
  66         char *items[];
  67 };
  68
  69 struct ima_rule_entry {
  70         struct list_head list;
  71         int action;
  72         unsigned int flags;
  73         enum ima_hooks func;
  74         int mask;
  75         unsigned long fsmagic;
  76         uuid_t fsuuid;
  77         kuid_t uid;
  78         kuid_t fowner;
  79         bool (*uid_op)(kuid_t, kuid_t);    /* Handlers for operators       */
  80         bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */
  81         int pcr;
  82         struct {
  83                 void *rule;     /* LSM file metadata specific */
  84                 char *args_p;   /* audit value */
  85                 int type;       /* audit type */
  86         } lsm[MAX_LSM_RULES];
  87         char *fsname;
  88         struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
  89         struct ima_rule_opt_list *label; /* Measure data grouped under this label */
  90         struct ima_template_desc *template;
  91 };
  92
  93 /*
  94  * Without LSM specific knowledge, the default policy can only be
  95  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  96  */
  97
  98 /*
  99  * The minimum rule set to allow for full TCB coverage.  Measures all files
 100  * opened or mmap for exec and everything read by root.  Dangerous because
 101  * normal users can easily run the machine out of memory simply building
 102  * and running executables.
 103  */
 104 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = {
 105         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 106         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 107         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 108         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 109         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 110         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 111         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 112         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 113         {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 114         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
 115          .flags = IMA_FSMAGIC},
 116         {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC,
 117          .flags = IMA_FSMAGIC},
 118         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 119         {.action = DONT_MEASURE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC}
 120 };
 121
 122 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = {
 123         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 124          .flags = IMA_FUNC | IMA_MASK},
 125         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 126          .flags = IMA_FUNC | IMA_MASK},
 127         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 128          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 129          .flags = IMA_FUNC | IMA_MASK | IMA_UID},
 130         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 131         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 132 };
 133
 134 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = {
 135         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 136          .flags = IMA_FUNC | IMA_MASK},
 137         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 138          .flags = IMA_FUNC | IMA_MASK},
 139         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 140          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 141          .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 142         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 143          .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq,
 144          .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 145         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 146         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 147         {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
 148 };
 149
 150 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = {
 151         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 152         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 153         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 154         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 155         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 156         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 157         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 158         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 159         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 160         {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC},
 161         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 162         {.action = DONT_APPRAISE, .fsmagic = EFIVARFS_MAGIC, .flags = IMA_FSMAGIC},
 163         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 164         {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 165 #ifdef CONFIG_IMA_WRITE_POLICY
 166         {.action = APPRAISE, .func = POLICY_CHECK,
 167         .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 168 #endif
 169 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 170         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 171          .flags = IMA_FOWNER},
 172 #else
 173         /* force signature */
 174         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq,
 175          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 176 #endif
 177 };
 178
 179 static struct ima_rule_entry build_appraise_rules[] __ro_after_init = {
 180 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_MODULE_SIGS
 181         {.action = APPRAISE, .func = MODULE_CHECK,
 182          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 183 #endif
 184 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_FIRMWARE_SIGS
 185         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 186          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 187 #endif
 188 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_KEXEC_SIGS
 189         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 190          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 191 #endif
 192 #ifdef CONFIG_IMA_APPRAISE_REQUIRE_POLICY_SIGS
 193         {.action = APPRAISE, .func = POLICY_CHECK,
 194          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 195 #endif
 196 };
 197
 198 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
 199         {.action = APPRAISE, .func = MODULE_CHECK,
 200          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 201         {.action = APPRAISE, .func = FIRMWARE_CHECK,
 202          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 203         {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK,
 204          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 205         {.action = APPRAISE, .func = POLICY_CHECK,
 206          .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
 207 };
 208
 209 static struct ima_rule_entry critical_data_rules[] __ro_after_init = {
 210         {.action = MEASURE, .func = CRITICAL_DATA, .flags = IMA_FUNC},
 211 };
 212
 213 /* An array of architecture specific rules */
 214 static struct ima_rule_entry *arch_policy_entry __ro_after_init;
 215
 216 static LIST_HEAD(ima_default_rules);
 217 static LIST_HEAD(ima_policy_rules);
 218 static LIST_HEAD(ima_temp_rules);
 219 static struct list_head *ima_rules = &ima_default_rules;
 220
 221 static int ima_policy __initdata;
 222
 223 static int __init default_measure_policy_setup(char *str)
 224 {
 225         if (ima_policy)
 226                 return 1;
 227
 228         ima_policy = ORIGINAL_TCB;
 229         return 1;
 230 }
 231 __setup("ima_tcb", default_measure_policy_setup);
 232
 233 static bool ima_use_appraise_tcb __initdata;
 234 static bool ima_use_secure_boot __initdata;
 235 static bool ima_use_critical_data __initdata;
 236 static bool ima_fail_unverifiable_sigs __ro_after_init;
 237 static int __init policy_setup(char *str)
 238 {
 239         char *p;
 240
 241         while ((p = strsep(&str, " |\n")) != NULL) {
 242                 if (*p == ' ')
 243                         continue;
 244                 if ((strcmp(p, "tcb") == 0) && !ima_policy)
 245                         ima_policy = DEFAULT_TCB;
 246                 else if (strcmp(p, "appraise_tcb") == 0)
 247                         ima_use_appraise_tcb = true;
 248                 else if (strcmp(p, "secure_boot") == 0)
 249                         ima_use_secure_boot = true;
 250                 else if (strcmp(p, "critical_data") == 0)
 251                         ima_use_critical_data = true;
 252                 else if (strcmp(p, "fail_securely") == 0)
 253                         ima_fail_unverifiable_sigs = true;
 254                 else
 255                         pr_err("policy \"%s\" not found", p);
 256         }
 257
 258         return 1;
 259 }
 260 __setup("ima_policy=", policy_setup);
 261
 262 static int __init default_appraise_policy_setup(char *str)
 263 {
 264         ima_use_appraise_tcb = true;
 265         return 1;
 266 }
 267 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 268
 269 static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
 270 {
 271         struct ima_rule_opt_list *opt_list;
 272         size_t count = 0;
 273         char *src_copy;
 274         char *cur, *next;
 275         size_t i;
 276
 277         src_copy = match_strdup(src);
 278         if (!src_copy)
 279                 return ERR_PTR(-ENOMEM);
 280
 281         next = src_copy;
 282         while ((cur = strsep(&next, "|"))) {
 283                 /* Don't accept an empty list item */
 284                 if (!(*cur)) {
 285                         kfree(src_copy);
 286                         return ERR_PTR(-EINVAL);
 287                 }
 288                 count++;
 289         }
 290
 291         /* Don't accept an empty list */
 292         if (!count) {
 293                 kfree(src_copy);
 294                 return ERR_PTR(-EINVAL);
 295         }
 296
 297         opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
 298         if (!opt_list) {
 299                 kfree(src_copy);
 300                 return ERR_PTR(-ENOMEM);
 301         }
 302
 303         /*
 304          * strsep() has already replaced all instances of '|' with '\0',
 305          * leaving a byte sequence of NUL-terminated strings. Reference each
 306          * string with the array of items.
 307          *
 308          * IMPORTANT: Ownership of the allocated buffer is transferred from
 309          * src_copy to the first element in the items array. To free the
 310          * buffer, kfree() must only be called on the first element of the
 311          * array.
 312          */
 313         for (i = 0, cur = src_copy; i < count; i++) {
 314                 opt_list->items[i] = cur;
 315                 cur = strchr(cur, '\0') + 1;
 316         }
 317         opt_list->count = count;
 318
 319         return opt_list;
 320 }
 321
 322 static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
 323 {
 324         if (!opt_list)
 325                 return;
 326
 327         if (opt_list->count) {
 328                 kfree(opt_list->items[0]);
 329                 opt_list->count = 0;
 330         }
 331
 332         kfree(opt_list);
 333 }
 334
 335 static void ima_lsm_free_rule(struct ima_rule_entry *entry)
 336 {
 337         int i;
 338
 339         for (i = 0; i < MAX_LSM_RULES; i++) {
 340                 ima_filter_rule_free(entry->lsm[i].rule);
 341                 kfree(entry->lsm[i].args_p);
 342         }
 343 }
 344
 345 static void ima_free_rule(struct ima_rule_entry *entry)
 346 {
 347         if (!entry)
 348                 return;
 349
 350         /*
 351          * entry->template->fields may be allocated in ima_parse_rule() but that
 352          * reference is owned by the corresponding ima_template_desc element in
 353          * the defined_templates list and cannot be freed here
 354          */
 355         kfree(entry->fsname);
 356         ima_free_rule_opt_list(entry->keyrings);
 357         ima_lsm_free_rule(entry);
 358         kfree(entry);
 359 }
 360
 361 static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry)
 362 {
 363         struct ima_rule_entry *nentry;
 364         int i;
 365
 366         /*
 367          * Immutable elements are copied over as pointers and data; only
 368          * lsm rules can change
 369          */
 370         nentry = kmemdup(entry, sizeof(*nentry), GFP_KERNEL);
 371         if (!nentry)
 372                 return NULL;
 373
 374         memset(nentry->lsm, 0, sizeof_field(struct ima_rule_entry, lsm));
 375
 376         for (i = 0; i < MAX_LSM_RULES; i++) {
 377                 if (!entry->lsm[i].args_p)
 378                         continue;
 379
 380                 nentry->lsm[i].type = entry->lsm[i].type;
 381                 nentry->lsm[i].args_p = entry->lsm[i].args_p;
 382                 /*
 383                  * Remove the reference from entry so that the associated
 384                  * memory will not be freed during a later call to
 385                  * ima_lsm_free_rule(entry).
 386                  */
 387                 entry->lsm[i].args_p = NULL;
 388
 389                 ima_filter_rule_init(nentry->lsm[i].type, Audit_equal,
 390                                      nentry->lsm[i].args_p,
 391                                      &nentry->lsm[i].rule);
 392                 if (!nentry->lsm[i].rule)
 393                         pr_warn("rule for LSM \'%s\' is undefined\n",
 394                                 nentry->lsm[i].args_p);
 395         }
 396         return nentry;
 397 }
 398
 399 static int ima_lsm_update_rule(struct ima_rule_entry *entry)
 400 {
 401         struct ima_rule_entry *nentry;
 402
 403         nentry = ima_lsm_copy_rule(entry);
 404         if (!nentry)
 405                 return -ENOMEM;
 406
 407         list_replace_rcu(&entry->list, &nentry->list);
 408         synchronize_rcu();
 409         /*
 410          * ima_lsm_copy_rule() shallow copied all references, except for the
 411          * LSM references, from entry to nentry so we only want to free the LSM
 412          * references and the entry itself. All other memory refrences will now
 413          * be owned by nentry.
 414          */
 415         ima_lsm_free_rule(entry);
 416         kfree(entry);
 417
 418         return 0;
 419 }
 420
 421 static bool ima_rule_contains_lsm_cond(struct ima_rule_entry *entry)
 422 {
 423         int i;
 424
 425         for (i = 0; i < MAX_LSM_RULES; i++)
 426                 if (entry->lsm[i].args_p)
 427                         return true;
 428
 429         return false;
 430 }
 431
 432 /*
 433  * The LSM policy can be reloaded, leaving the IMA LSM based rules referring
 434  * to the old, stale LSM policy.  Update the IMA LSM based rules to reflect
 435  * the reloaded LSM policy.
 436  */
 437 static void ima_lsm_update_rules(void)
 438 {
 439         struct ima_rule_entry *entry, *e;
 440         int result;
 441
 442         list_for_each_entry_safe(entry, e, &ima_policy_rules, list) {
 443                 if (!ima_rule_contains_lsm_cond(entry))
 444                         continue;
 445
 446                 result = ima_lsm_update_rule(entry);
 447                 if (result) {
 448                         pr_err("lsm rule update error %d\n", result);
 449                         return;
 450                 }
 451         }
 452 }
 453
 454 int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
 455                           void *lsm_data)
 456 {
 457         if (event != LSM_POLICY_CHANGE)
 458                 return NOTIFY_DONE;
 459
 460         ima_lsm_update_rules();
 461         return NOTIFY_OK;
 462 }
 463
 464 /**
 465  * ima_match_rule_data - determine whether func_data matches the policy rule
 466  * @rule: a pointer to a rule
 467  * @func_data: data to match against the measure rule data
 468  * @cred: a pointer to a credentials structure for user validation
 469  *
 470  * Returns true if func_data matches one in the rule, false otherwise.
 471  */
 472 static bool ima_match_rule_data(struct ima_rule_entry *rule,
 473                                 const char *func_data,
 474                                 const struct cred *cred)
 475 {
 476         const struct ima_rule_opt_list *opt_list = NULL;
 477         bool matched = false;
 478         size_t i;
 479
 480         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 481                 return false;
 482
 483         switch (rule->func) {
 484         case KEY_CHECK:
 485                 if (!rule->keyrings)
 486                         return true;
 487
 488                 opt_list = rule->keyrings;
 489                 break;
 490         case CRITICAL_DATA:
 491                 if (!rule->label)
 492                         return true;
 493
 494                 opt_list = rule->label;
 495                 break;
 496         default:
 497                 return false;
 498         }
 499
 500         if (!func_data)
 501                 return false;
 502
 503         for (i = 0; i < opt_list->count; i++) {
 504                 if (!strcmp(opt_list->items[i], func_data)) {
 505                         matched = true;
 506                         break;
 507                 }
 508         }
 509
 510         return matched;
 511 }
 512
 513 /**
 514  * ima_match_rules - determine whether an inode matches the policy rule.
 515  * @rule: a pointer to a rule
 516  * @mnt_userns: user namespace of the mount the inode was found from
 517  * @inode: a pointer to an inode
 518  * @cred: a pointer to a credentials structure for user validation
 519  * @secid: the secid of the task to be validated
 520  * @func: LIM hook identifier
 521  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 522  * @func_data: func specific data, may be NULL
 523  *
 524  * Returns true on rule match, false on failure.
 525  */
 526 static bool ima_match_rules(struct ima_rule_entry *rule,
 527                             struct user_namespace *mnt_userns,
 528                             struct inode *inode, const struct cred *cred,
 529                             u32 secid, enum ima_hooks func, int mask,
 530                             const char *func_data)
 531 {
 532         int i;
 533
 534         if ((rule->flags & IMA_FUNC) &&
 535             (rule->func != func && func != POST_SETATTR))
 536                 return false;
 537
 538         switch (func) {
 539         case KEY_CHECK:
 540         case CRITICAL_DATA:
 541                 return ((rule->func == func) &&
 542                         ima_match_rule_data(rule, func_data, cred));
 543         default:
 544                 break;
 545         }
 546
 547         if ((rule->flags & IMA_MASK) &&
 548             (rule->mask != mask && func != POST_SETATTR))
 549                 return false;
 550         if ((rule->flags & IMA_INMASK) &&
 551             (!(rule->mask & mask) && func != POST_SETATTR))
 552                 return false;
 553         if ((rule->flags & IMA_FSMAGIC)
 554             && rule->fsmagic != inode->i_sb->s_magic)
 555                 return false;
 556         if ((rule->flags & IMA_FSNAME)
 557             && strcmp(rule->fsname, inode->i_sb->s_type->name))
 558                 return false;
 559         if ((rule->flags & IMA_FSUUID) &&
 560             !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid))
 561                 return false;
 562         if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
 563                 return false;
 564         if (rule->flags & IMA_EUID) {
 565                 if (has_capability_noaudit(current, CAP_SETUID)) {
 566                         if (!rule->uid_op(cred->euid, rule->uid)
 567                             && !rule->uid_op(cred->suid, rule->uid)
 568                             && !rule->uid_op(cred->uid, rule->uid))
 569                                 return false;
 570                 } else if (!rule->uid_op(cred->euid, rule->uid))
 571                         return false;
 572         }
 573
 574         if ((rule->flags & IMA_FOWNER) &&
 575             !rule->fowner_op(i_uid_into_mnt(mnt_userns, inode), rule->fowner))
 576                 return false;
 577         for (i = 0; i < MAX_LSM_RULES; i++) {
 578                 int rc = 0;
 579                 u32 osid;
 580
 581                 if (!rule->lsm[i].rule) {
 582                         if (!rule->lsm[i].args_p)
 583                                 continue;
 584                         else
 585                                 return false;
 586                 }
 587                 switch (i) {
 588                 case LSM_OBJ_USER:
 589                 case LSM_OBJ_ROLE:
 590                 case LSM_OBJ_TYPE:
 591                         security_inode_getsecid(inode, &osid);
 592                         rc = ima_filter_rule_match(osid, rule->lsm[i].type,
 593                                                    Audit_equal,
 594                                                    rule->lsm[i].rule);
 595                         break;
 596                 case LSM_SUBJ_USER:
 597                 case LSM_SUBJ_ROLE:
 598                 case LSM_SUBJ_TYPE:
 599                         rc = ima_filter_rule_match(secid, rule->lsm[i].type,
 600                                                    Audit_equal,
 601                                                    rule->lsm[i].rule);
 602                 default:
 603                         break;
 604                 }
 605                 if (!rc)
 606                         return false;
 607         }
 608         return true;
 609 }
 610
 611 /*
 612  * In addition to knowing that we need to appraise the file in general,
 613  * we need to differentiate between calling hooks, for hook specific rules.
 614  */
 615 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 616 {
 617         if (!(rule->flags & IMA_FUNC))
 618                 return IMA_FILE_APPRAISE;
 619
 620         switch (func) {
 621         case MMAP_CHECK:
 622                 return IMA_MMAP_APPRAISE;
 623         case BPRM_CHECK:
 624                 return IMA_BPRM_APPRAISE;
 625         case CREDS_CHECK:
 626                 return IMA_CREDS_APPRAISE;
 627         case FILE_CHECK:
 628         case POST_SETATTR:
 629                 return IMA_FILE_APPRAISE;
 630         case MODULE_CHECK ... MAX_CHECK - 1:
 631         default:
 632                 return IMA_READ_APPRAISE;
 633         }
 634 }
 635
 636 /**
 637  * ima_match_policy - decision based on LSM and other conditions
 638  * @mnt_userns: user namespace of the mount the inode was found from
 639  * @inode: pointer to an inode for which the policy decision is being made
 640  * @cred: pointer to a credentials structure for which the policy decision is
 641  *        being made
 642  * @secid: LSM secid of the task to be validated
 643  * @func: IMA hook identifier
 644  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 645  * @pcr: set the pcr to extend
 646  * @template_desc: the template that should be used for this rule
 647  * @func_data: func specific data, may be NULL
 648  *
 649  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 650  * conditions.
 651  *
 652  * Since the IMA policy may be updated multiple times we need to lock the
 653  * list when walking it.  Reads are many orders of magnitude more numerous
 654  * than writes so ima_match_policy() is classical RCU candidate.
 655  */
 656 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 657                      const struct cred *cred, u32 secid, enum ima_hooks func,
 658                      int mask, int flags, int *pcr,
 659                      struct ima_template_desc **template_desc,
 660                      const char *func_data)
 661 {
 662         struct ima_rule_entry *entry;
 663         int action = 0, actmask = flags | (flags << 1);
 664
 665         if (template_desc && !*template_desc)
 666                 *template_desc = ima_template_desc_current();
 667
 668         rcu_read_lock();
 669         list_for_each_entry_rcu(entry, ima_rules, list) {
 670
 671                 if (!(entry->action & actmask))
 672                         continue;
 673
 674                 if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
 675                                      func, mask, func_data))
 676                         continue;
 677
 678                 action |= entry->flags & IMA_ACTION_FLAGS;
 679
 680                 action |= entry->action & IMA_DO_MASK;
 681                 if (entry->action & IMA_APPRAISE) {
 682                         action |= get_subaction(entry, func);
 683                         action &= ~IMA_HASH;
 684                         if (ima_fail_unverifiable_sigs)
 685                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 686                 }
 687
 688
 689                 if (entry->action & IMA_DO_MASK)
 690                         actmask &= ~(entry->action | entry->action << 1);
 691                 else
 692                         actmask &= ~(entry->action | entry->action >> 1);
 693
 694                 if ((pcr) && (entry->flags & IMA_PCR))
 695                         *pcr = entry->pcr;
 696
 697                 if (template_desc && entry->template)
 698                         *template_desc = entry->template;
 699
 700                 if (!actmask)
 701                         break;
 702         }
 703         rcu_read_unlock();
 704
 705         return action;
 706 }
 707
 708 /*
 709  * Initialize the ima_policy_flag variable based on the currently
 710  * loaded policy.  Based on this flag, the decision to short circuit
 711  * out of a function or not call the function in the first place
 712  * can be made earlier.
 713  */
 714 void ima_update_policy_flag(void)
 715 {
 716         struct ima_rule_entry *entry;
 717
 718         list_for_each_entry(entry, ima_rules, list) {
 719                 if (entry->action & IMA_DO_MASK)
 720                         ima_policy_flag |= entry->action;
 721         }
 722
 723         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 724         if (!ima_appraise)
 725                 ima_policy_flag &= ~IMA_APPRAISE;
 726 }
 727
 728 static int ima_appraise_flag(enum ima_hooks func)
 729 {
 730         if (func == MODULE_CHECK)
 731                 return IMA_APPRAISE_MODULES;
 732         else if (func == FIRMWARE_CHECK)
 733                 return IMA_APPRAISE_FIRMWARE;
 734         else if (func == POLICY_CHECK)
 735                 return IMA_APPRAISE_POLICY;
 736         else if (func == KEXEC_KERNEL_CHECK)
 737                 return IMA_APPRAISE_KEXEC;
 738         return 0;
 739 }
 740
 741 static void add_rules(struct ima_rule_entry *entries, int count,
 742                       enum policy_rule_list policy_rule)
 743 {
 744         int i = 0;
 745
 746         for (i = 0; i < count; i++) {
 747                 struct ima_rule_entry *entry;
 748
 749                 if (policy_rule & IMA_DEFAULT_POLICY)
 750                         list_add_tail(&entries[i].list, &ima_default_rules);
 751
 752                 if (policy_rule & IMA_CUSTOM_POLICY) {
 753                         entry = kmemdup(&entries[i], sizeof(*entry),
 754                                         GFP_KERNEL);
 755                         if (!entry)
 756                                 continue;
 757
 758                         list_add_tail(&entry->list, &ima_policy_rules);
 759                 }
 760                 if (entries[i].action == APPRAISE) {
 761                         if (entries != build_appraise_rules)
 762                                 temp_ima_appraise |=
 763                                         ima_appraise_flag(entries[i].func);
 764                         else
 765                                 build_ima_appraise |=
 766                                         ima_appraise_flag(entries[i].func);
 767                 }
 768         }
 769 }
 770
 771 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 772
 773 static int __init ima_init_arch_policy(void)
 774 {
 775         const char * const *arch_rules;
 776         const char * const *rules;
 777         int arch_entries = 0;
 778         int i = 0;
 779
 780         arch_rules = arch_get_ima_policy();
 781         if (!arch_rules)
 782                 return arch_entries;
 783
 784         /* Get number of rules */
 785         for (rules = arch_rules; *rules != NULL; rules++)
 786                 arch_entries++;
 787
 788         arch_policy_entry = kcalloc(arch_entries + 1,
 789                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 790         if (!arch_policy_entry)
 791                 return 0;
 792
 793         /* Convert each policy string rules to struct ima_rule_entry format */
 794         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 795                 char rule[255];
 796                 int result;
 797
 798                 result = strlcpy(rule, *rules, sizeof(rule));
 799
 800                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 801                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 802                 if (result) {
 803                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 804                                 rule);
 805                         memset(&arch_policy_entry[i], 0,
 806                                sizeof(*arch_policy_entry));
 807                         continue;
 808                 }
 809                 i++;
 810         }
 811         return i;
 812 }
 813
 814 /**
 815  * ima_init_policy - initialize the default measure rules.
 816  *
 817  * ima_rules points to either the ima_default_rules or the
 818  * the new ima_policy_rules.
 819  */
 820 void __init ima_init_policy(void)
 821 {
 822         int build_appraise_entries, arch_entries;
 823
 824         /* if !ima_policy, we load NO default rules */
 825         if (ima_policy)
 826                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 827                           IMA_DEFAULT_POLICY);
 828
 829         switch (ima_policy) {
 830         case ORIGINAL_TCB:
 831                 add_rules(original_measurement_rules,
 832                           ARRAY_SIZE(original_measurement_rules),
 833                           IMA_DEFAULT_POLICY);
 834                 break;
 835         case DEFAULT_TCB:
 836                 add_rules(default_measurement_rules,
 837                           ARRAY_SIZE(default_measurement_rules),
 838                           IMA_DEFAULT_POLICY);
 839         default:
 840                 break;
 841         }
 842
 843         /*
 844          * Based on runtime secure boot flags, insert arch specific measurement
 845          * and appraise rules requiring file signatures for both the initial
 846          * and custom policies, prior to other appraise rules.
 847          * (Highest priority)
 848          */
 849         arch_entries = ima_init_arch_policy();
 850         if (!arch_entries)
 851                 pr_info("No architecture policies found\n");
 852         else
 853                 add_rules(arch_policy_entry, arch_entries,
 854                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 855
 856         /*
 857          * Insert the builtin "secure_boot" policy rules requiring file
 858          * signatures, prior to other appraise rules.
 859          */
 860         if (ima_use_secure_boot)
 861                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 862                           IMA_DEFAULT_POLICY);
 863
 864         /*
 865          * Insert the build time appraise rules requiring file signatures
 866          * for both the initial and custom policies, prior to other appraise
 867          * rules. As the secure boot rules includes all of the build time
 868          * rules, include either one or the other set of rules, but not both.
 869          */
 870         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 871         if (build_appraise_entries) {
 872                 if (ima_use_secure_boot)
 873                         add_rules(build_appraise_rules, build_appraise_entries,
 874                                   IMA_CUSTOM_POLICY);
 875                 else
 876                         add_rules(build_appraise_rules, build_appraise_entries,
 877                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 878         }
 879
 880         if (ima_use_appraise_tcb)
 881                 add_rules(default_appraise_rules,
 882                           ARRAY_SIZE(default_appraise_rules),
 883                           IMA_DEFAULT_POLICY);
 884
 885         if (ima_use_critical_data)
 886                 add_rules(critical_data_rules,
 887                           ARRAY_SIZE(critical_data_rules),
 888                           IMA_DEFAULT_POLICY);
 889
 890         ima_update_policy_flag();
 891 }
 892
 893 /* Make sure we have a valid policy, at least containing some rules. */
 894 int ima_check_policy(void)
 895 {
 896         if (list_empty(&ima_temp_rules))
 897                 return -EINVAL;
 898         return 0;
 899 }
 900
 901 /**
 902  * ima_update_policy - update default_rules with new measure rules
 903  *
 904  * Called on file .release to update the default rules with a complete new
 905  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
 906  * they make a queue.  The policy may be updated multiple times and this is the
 907  * RCU updater.
 908  *
 909  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
 910  * we switch from the default policy to user defined.
 911  */
 912 void ima_update_policy(void)
 913 {
 914         struct list_head *policy = &ima_policy_rules;
 915
 916         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
 917
 918         if (ima_rules != policy) {
 919                 ima_policy_flag = 0;
 920                 ima_rules = policy;
 921
 922                 /*
 923                  * IMA architecture specific policy rules are specified
 924                  * as strings and converted to an array of ima_entry_rules
 925                  * on boot.  After loading a custom policy, free the
 926                  * architecture specific rules stored as an array.
 927                  */
 928                 kfree(arch_policy_entry);
 929         }
 930         ima_update_policy_flag();
 931
 932         /* Custom IMA policy has been loaded */
 933         ima_process_queued_keys();
 934 }
 935
 936 /* Keep the enumeration in sync with the policy_tokens! */
 937 enum {
 938         Opt_measure, Opt_dont_measure,
 939         Opt_appraise, Opt_dont_appraise,
 940         Opt_audit, Opt_hash, Opt_dont_hash,
 941         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 942         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 943         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
 944         Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
 945         Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 946         Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
 947         Opt_appraise_type, Opt_appraise_flag,
 948         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
 949         Opt_label, Opt_err
 950 };
 951
 952 static const match_table_t policy_tokens = {
 953         {Opt_measure, "measure"},
 954         {Opt_dont_measure, "dont_measure"},
 955         {Opt_appraise, "appraise"},
 956         {Opt_dont_appraise, "dont_appraise"},
 957         {Opt_audit, "audit"},
 958         {Opt_hash, "hash"},
 959         {Opt_dont_hash, "dont_hash"},
 960         {Opt_obj_user, "obj_user=%s"},
 961         {Opt_obj_role, "obj_role=%s"},
 962         {Opt_obj_type, "obj_type=%s"},
 963         {Opt_subj_user, "subj_user=%s"},
 964         {Opt_subj_role, "subj_role=%s"},
 965         {Opt_subj_type, "subj_type=%s"},
 966         {Opt_func, "func=%s"},
 967         {Opt_mask, "mask=%s"},
 968         {Opt_fsmagic, "fsmagic=%s"},
 969         {Opt_fsname, "fsname=%s"},
 970         {Opt_fsuuid, "fsuuid=%s"},
 971         {Opt_uid_eq, "uid=%s"},
 972         {Opt_euid_eq, "euid=%s"},
 973         {Opt_fowner_eq, "fowner=%s"},
 974         {Opt_uid_gt, "uid>%s"},
 975         {Opt_euid_gt, "euid>%s"},
 976         {Opt_fowner_gt, "fowner>%s"},
 977         {Opt_uid_lt, "uid<%s"},
 978         {Opt_euid_lt, "euid<%s"},
 979         {Opt_fowner_lt, "fowner<%s"},
 980         {Opt_appraise_type, "appraise_type=%s"},
 981         {Opt_appraise_flag, "appraise_flag=%s"},
 982         {Opt_permit_directio, "permit_directio"},
 983         {Opt_pcr, "pcr=%s"},
 984         {Opt_template, "template=%s"},
 985         {Opt_keyrings, "keyrings=%s"},
 986         {Opt_label, "label=%s"},
 987         {Opt_err, NULL}
 988 };
 989
 990 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 991                              substring_t *args, int lsm_rule, int audit_type)
 992 {
 993         int result;
 994
 995         if (entry->lsm[lsm_rule].rule)
 996                 return -EINVAL;
 997
 998         entry->lsm[lsm_rule].args_p = match_strdup(args);
 999         if (!entry->lsm[lsm_rule].args_p)
1000                 return -ENOMEM;
1001
1002         entry->lsm[lsm_rule].type = audit_type;
1003         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1004                                       entry->lsm[lsm_rule].args_p,
1005                                       &entry->lsm[lsm_rule].rule);
1006         if (!entry->lsm[lsm_rule].rule) {
1007                 pr_warn("rule for LSM \'%s\' is undefined\n",
1008                         entry->lsm[lsm_rule].args_p);
1009
1010                 if (ima_rules == &ima_default_rules) {
1011                         kfree(entry->lsm[lsm_rule].args_p);
1012                         entry->lsm[lsm_rule].args_p = NULL;
1013                         result = -EINVAL;
1014                 } else
1015                         result = 0;
1016         }
1017
1018         return result;
1019 }
1020
1021 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1022                               bool (*rule_operator)(kuid_t, kuid_t))
1023 {
1024         if (!ab)
1025                 return;
1026
1027         if (rule_operator == &uid_gt)
1028                 audit_log_format(ab, "%s>", key);
1029         else if (rule_operator == &uid_lt)
1030                 audit_log_format(ab, "%s<", key);
1031         else
1032                 audit_log_format(ab, "%s=", key);
1033         audit_log_format(ab, "%s ", value);
1034 }
1035 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1036 {
1037         ima_log_string_op(ab, key, value, NULL);
1038 }
1039
1040 /*
1041  * Validating the appended signature included in the measurement list requires
1042  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1043  * field). Therefore, notify the user if they have the 'modsig' field but not
1044  * the 'd-modsig' field in the template.
1045  */
1046 static void check_template_modsig(const struct ima_template_desc *template)
1047 {
1048 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1049         bool has_modsig, has_dmodsig;
1050         static bool checked;
1051         int i;
1052
1053         /* We only need to notify the user once. */
1054         if (checked)
1055                 return;
1056
1057         has_modsig = has_dmodsig = false;
1058         for (i = 0; i < template->num_fields; i++) {
1059                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1060                         has_modsig = true;
1061                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1062                         has_dmodsig = true;
1063         }
1064
1065         if (has_modsig && !has_dmodsig)
1066                 pr_notice(MSG);
1067
1068         checked = true;
1069 #undef MSG
1070 }
1071
1072 static bool ima_validate_rule(struct ima_rule_entry *entry)
1073 {
1074         /* Ensure that the action is set and is compatible with the flags */
1075         if (entry->action == UNKNOWN)
1076                 return false;
1077
1078         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1079                 return false;
1080
1081         if (entry->action != APPRAISE &&
1082             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
1083                 return false;
1084
1085         /*
1086          * The IMA_FUNC bit must be set if and only if there's a valid hook
1087          * function specified, and vice versa. Enforcing this property allows
1088          * for the NONE case below to validate a rule without an explicit hook
1089          * function.
1090          */
1091         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1092             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1093                 return false;
1094
1095         /*
1096          * Ensure that the hook function is compatible with the other
1097          * components of the rule
1098          */
1099         switch (entry->func) {
1100         case NONE:
1101         case FILE_CHECK:
1102         case MMAP_CHECK:
1103         case BPRM_CHECK:
1104         case CREDS_CHECK:
1105         case POST_SETATTR:
1106         case FIRMWARE_CHECK:
1107         case POLICY_CHECK:
1108                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1109                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1110                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1111                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1112                                      IMA_PERMIT_DIRECTIO))
1113                         return false;
1114
1115                 break;
1116         case MODULE_CHECK:
1117         case KEXEC_KERNEL_CHECK:
1118         case KEXEC_INITRAMFS_CHECK:
1119                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1120                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1121                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1122                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1123                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1124                                      IMA_CHECK_BLACKLIST))
1125                         return false;
1126
1127                 break;
1128         case KEXEC_CMDLINE:
1129                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1130                         return false;
1131
1132                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1133                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1134                                      IMA_PCR | IMA_FSNAME))
1135                         return false;
1136
1137                 break;
1138         case KEY_CHECK:
1139                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1140                         return false;
1141
1142                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1143                                      IMA_KEYRINGS))
1144                         return false;
1145
1146                 if (ima_rule_contains_lsm_cond(entry))
1147                         return false;
1148
1149                 break;
1150         case CRITICAL_DATA:
1151                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1152                         return false;
1153
1154                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1155                                      IMA_LABEL))
1156                         return false;
1157
1158                 if (ima_rule_contains_lsm_cond(entry))
1159                         return false;
1160
1161                 break;
1162         default:
1163                 return false;
1164         }
1165
1166         /* Ensure that combinations of flags are compatible with each other */
1167         if (entry->flags & IMA_CHECK_BLACKLIST &&
1168             !(entry->flags & IMA_MODSIG_ALLOWED))
1169                 return false;
1170
1171         return true;
1172 }
1173
1174 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1175 {
1176         struct audit_buffer *ab;
1177         char *from;
1178         char *p;
1179         bool uid_token;
1180         struct ima_template_desc *template_desc;
1181         int result = 0;
1182
1183         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1184                                        AUDIT_INTEGRITY_POLICY_RULE);
1185
1186         entry->uid = INVALID_UID;
1187         entry->fowner = INVALID_UID;
1188         entry->uid_op = &uid_eq;
1189         entry->fowner_op = &uid_eq;
1190         entry->action = UNKNOWN;
1191         while ((p = strsep(&rule, " \t")) != NULL) {
1192                 substring_t args[MAX_OPT_ARGS];
1193                 int token;
1194                 unsigned long lnum;
1195
1196                 if (result < 0)
1197                         break;
1198                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1199                         continue;
1200                 token = match_token(p, policy_tokens, args);
1201                 switch (token) {
1202                 case Opt_measure:
1203                         ima_log_string(ab, "action", "measure");
1204
1205                         if (entry->action != UNKNOWN)
1206                                 result = -EINVAL;
1207
1208                         entry->action = MEASURE;
1209                         break;
1210                 case Opt_dont_measure:
1211                         ima_log_string(ab, "action", "dont_measure");
1212
1213                         if (entry->action != UNKNOWN)
1214                                 result = -EINVAL;
1215
1216                         entry->action = DONT_MEASURE;
1217                         break;
1218                 case Opt_appraise:
1219                         ima_log_string(ab, "action", "appraise");
1220
1221                         if (entry->action != UNKNOWN)
1222                                 result = -EINVAL;
1223
1224                         entry->action = APPRAISE;
1225                         break;
1226                 case Opt_dont_appraise:
1227                         ima_log_string(ab, "action", "dont_appraise");
1228
1229                         if (entry->action != UNKNOWN)
1230                                 result = -EINVAL;
1231
1232                         entry->action = DONT_APPRAISE;
1233                         break;
1234                 case Opt_audit:
1235                         ima_log_string(ab, "action", "audit");
1236
1237                         if (entry->action != UNKNOWN)
1238                                 result = -EINVAL;
1239
1240                         entry->action = AUDIT;
1241                         break;
1242                 case Opt_hash:
1243                         ima_log_string(ab, "action", "hash");
1244
1245                         if (entry->action != UNKNOWN)
1246                                 result = -EINVAL;
1247
1248                         entry->action = HASH;
1249                         break;
1250                 case Opt_dont_hash:
1251                         ima_log_string(ab, "action", "dont_hash");
1252
1253                         if (entry->action != UNKNOWN)
1254                                 result = -EINVAL;
1255
1256                         entry->action = DONT_HASH;
1257                         break;
1258                 case Opt_func:
1259                         ima_log_string(ab, "func", args[0].from);
1260
1261                         if (entry->func)
1262                                 result = -EINVAL;
1263
1264                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1265                                 entry->func = FILE_CHECK;
1266                         /* PATH_CHECK is for backwards compat */
1267                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1268                                 entry->func = FILE_CHECK;
1269                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1270                                 entry->func = MODULE_CHECK;
1271                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1272                                 entry->func = FIRMWARE_CHECK;
1273                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1274                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1275                                 entry->func = MMAP_CHECK;
1276                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1277                                 entry->func = BPRM_CHECK;
1278                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1279                                 entry->func = CREDS_CHECK;
1280                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1281                                  0)
1282                                 entry->func = KEXEC_KERNEL_CHECK;
1283                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1284                                  == 0)
1285                                 entry->func = KEXEC_INITRAMFS_CHECK;
1286                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1287                                 entry->func = POLICY_CHECK;
1288                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1289                                 entry->func = KEXEC_CMDLINE;
1290                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1291                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1292                                 entry->func = KEY_CHECK;
1293                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1294                                 entry->func = CRITICAL_DATA;
1295                         else
1296                                 result = -EINVAL;
1297                         if (!result)
1298                                 entry->flags |= IMA_FUNC;
1299                         break;
1300                 case Opt_mask:
1301                         ima_log_string(ab, "mask", args[0].from);
1302
1303                         if (entry->mask)
1304                                 result = -EINVAL;
1305
1306                         from = args[0].from;
1307                         if (*from == '^')
1308                                 from++;
1309
1310                         if ((strcmp(from, "MAY_EXEC")) == 0)
1311                                 entry->mask = MAY_EXEC;
1312                         else if (strcmp(from, "MAY_WRITE") == 0)
1313                                 entry->mask = MAY_WRITE;
1314                         else if (strcmp(from, "MAY_READ") == 0)
1315                                 entry->mask = MAY_READ;
1316                         else if (strcmp(from, "MAY_APPEND") == 0)
1317                                 entry->mask = MAY_APPEND;
1318                         else
1319                                 result = -EINVAL;
1320                         if (!result)
1321                                 entry->flags |= (*args[0].from == '^')
1322                                      ? IMA_INMASK : IMA_MASK;
1323                         break;
1324                 case Opt_fsmagic:
1325                         ima_log_string(ab, "fsmagic", args[0].from);
1326
1327                         if (entry->fsmagic) {
1328                                 result = -EINVAL;
1329                                 break;
1330                         }
1331
1332                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1333                         if (!result)
1334                                 entry->flags |= IMA_FSMAGIC;
1335                         break;
1336                 case Opt_fsname:
1337                         ima_log_string(ab, "fsname", args[0].from);
1338
1339                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1340                         if (!entry->fsname) {
1341                                 result = -ENOMEM;
1342                                 break;
1343                         }
1344                         result = 0;
1345                         entry->flags |= IMA_FSNAME;
1346                         break;
1347                 case Opt_keyrings:
1348                         ima_log_string(ab, "keyrings", args[0].from);
1349
1350                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1351                             entry->keyrings) {
1352                                 result = -EINVAL;
1353                                 break;
1354                         }
1355
1356                         entry->keyrings = ima_alloc_rule_opt_list(args);
1357                         if (IS_ERR(entry->keyrings)) {
1358                                 result = PTR_ERR(entry->keyrings);
1359                                 entry->keyrings = NULL;
1360                                 break;
1361                         }
1362
1363                         entry->flags |= IMA_KEYRINGS;
1364                         break;
1365                 case Opt_label:
1366                         ima_log_string(ab, "label", args[0].from);
1367
1368                         if (entry->label) {
1369                                 result = -EINVAL;
1370                                 break;
1371                         }
1372
1373                         entry->label = ima_alloc_rule_opt_list(args);
1374                         if (IS_ERR(entry->label)) {
1375                                 result = PTR_ERR(entry->label);
1376                                 entry->label = NULL;
1377                                 break;
1378                         }
1379
1380                         entry->flags |= IMA_LABEL;
1381                         break;
1382                 case Opt_fsuuid:
1383                         ima_log_string(ab, "fsuuid", args[0].from);
1384
1385                         if (!uuid_is_null(&entry->fsuuid)) {
1386                                 result = -EINVAL;
1387                                 break;
1388                         }
1389
1390                         result = uuid_parse(args[0].from, &entry->fsuuid);
1391                         if (!result)
1392                                 entry->flags |= IMA_FSUUID;
1393                         break;
1394                 case Opt_uid_gt:
1395                 case Opt_euid_gt:
1396                         entry->uid_op = &uid_gt;
1397                         fallthrough;
1398                 case Opt_uid_lt:
1399                 case Opt_euid_lt:
1400                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1401                                 entry->uid_op = &uid_lt;
1402                         fallthrough;
1403                 case Opt_uid_eq:
1404                 case Opt_euid_eq:
1405                         uid_token = (token == Opt_uid_eq) ||
1406                                     (token == Opt_uid_gt) ||
1407                                     (token == Opt_uid_lt);
1408
1409                         ima_log_string_op(ab, uid_token ? "uid" : "euid",
1410                                           args[0].from, entry->uid_op);
1411
1412                         if (uid_valid(entry->uid)) {
1413                                 result = -EINVAL;
1414                                 break;
1415                         }
1416
1417                         result = kstrtoul(args[0].from, 10, &lnum);
1418                         if (!result) {
1419                                 entry->uid = make_kuid(current_user_ns(),
1420                                                        (uid_t) lnum);
1421                                 if (!uid_valid(entry->uid) ||
1422                                     (uid_t)lnum != lnum)
1423                                         result = -EINVAL;
1424                                 else
1425                                         entry->flags |= uid_token
1426                                             ? IMA_UID : IMA_EUID;
1427                         }
1428                         break;
1429                 case Opt_fowner_gt:
1430                         entry->fowner_op = &uid_gt;
1431                         fallthrough;
1432                 case Opt_fowner_lt:
1433                         if (token == Opt_fowner_lt)
1434                                 entry->fowner_op = &uid_lt;
1435                         fallthrough;
1436                 case Opt_fowner_eq:
1437                         ima_log_string_op(ab, "fowner", args[0].from,
1438                                           entry->fowner_op);
1439
1440                         if (uid_valid(entry->fowner)) {
1441                                 result = -EINVAL;
1442                                 break;
1443                         }
1444
1445                         result = kstrtoul(args[0].from, 10, &lnum);
1446                         if (!result) {
1447                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
1448                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
1449                                         result = -EINVAL;
1450                                 else
1451                                         entry->flags |= IMA_FOWNER;
1452                         }
1453                         break;
1454                 case Opt_obj_user:
1455                         ima_log_string(ab, "obj_user", args[0].from);
1456                         result = ima_lsm_rule_init(entry, args,
1457                                                    LSM_OBJ_USER,
1458                                                    AUDIT_OBJ_USER);
1459                         break;
1460                 case Opt_obj_role:
1461                         ima_log_string(ab, "obj_role", args[0].from);
1462                         result = ima_lsm_rule_init(entry, args,
1463                                                    LSM_OBJ_ROLE,
1464                                                    AUDIT_OBJ_ROLE);
1465                         break;
1466                 case Opt_obj_type:
1467                         ima_log_string(ab, "obj_type", args[0].from);
1468                         result = ima_lsm_rule_init(entry, args,
1469                                                    LSM_OBJ_TYPE,
1470                                                    AUDIT_OBJ_TYPE);
1471                         break;
1472                 case Opt_subj_user:
1473                         ima_log_string(ab, "subj_user", args[0].from);
1474                         result = ima_lsm_rule_init(entry, args,
1475                                                    LSM_SUBJ_USER,
1476                                                    AUDIT_SUBJ_USER);
1477                         break;
1478                 case Opt_subj_role:
1479                         ima_log_string(ab, "subj_role", args[0].from);
1480                         result = ima_lsm_rule_init(entry, args,
1481                                                    LSM_SUBJ_ROLE,
1482                                                    AUDIT_SUBJ_ROLE);
1483                         break;
1484                 case Opt_subj_type:
1485                         ima_log_string(ab, "subj_type", args[0].from);
1486                         result = ima_lsm_rule_init(entry, args,
1487                                                    LSM_SUBJ_TYPE,
1488                                                    AUDIT_SUBJ_TYPE);
1489                         break;
1490                 case Opt_appraise_type:
1491                         ima_log_string(ab, "appraise_type", args[0].from);
1492                         if ((strcmp(args[0].from, "imasig")) == 0)
1493                                 entry->flags |= IMA_DIGSIG_REQUIRED;
1494                         else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1495                                  strcmp(args[0].from, "imasig|modsig") == 0)
1496                                 entry->flags |= IMA_DIGSIG_REQUIRED |
1497                                                 IMA_MODSIG_ALLOWED;
1498                         else
1499                                 result = -EINVAL;
1500                         break;
1501                 case Opt_appraise_flag:
1502                         ima_log_string(ab, "appraise_flag", args[0].from);
1503                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1504                             strstr(args[0].from, "blacklist"))
1505                                 entry->flags |= IMA_CHECK_BLACKLIST;
1506                         else
1507                                 result = -EINVAL;
1508                         break;
1509                 case Opt_permit_directio:
1510                         entry->flags |= IMA_PERMIT_DIRECTIO;
1511                         break;
1512                 case Opt_pcr:
1513                         ima_log_string(ab, "pcr", args[0].from);
1514
1515                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1516                         if (result || INVALID_PCR(entry->pcr))
1517                                 result = -EINVAL;
1518                         else
1519                                 entry->flags |= IMA_PCR;
1520
1521                         break;
1522                 case Opt_template:
1523                         ima_log_string(ab, "template", args[0].from);
1524                         if (entry->action != MEASURE) {
1525                                 result = -EINVAL;
1526                                 break;
1527                         }
1528                         template_desc = lookup_template_desc(args[0].from);
1529                         if (!template_desc || entry->template) {
1530                                 result = -EINVAL;
1531                                 break;
1532                         }
1533
1534                         /*
1535                          * template_desc_init_fields() does nothing if
1536                          * the template is already initialised, so
1537                          * it's safe to do this unconditionally
1538                          */
1539                         template_desc_init_fields(template_desc->fmt,
1540                                                  &(template_desc->fields),
1541                                                  &(template_desc->num_fields));
1542                         entry->template = template_desc;
1543                         break;
1544                 case Opt_err:
1545                         ima_log_string(ab, "UNKNOWN", p);
1546                         result = -EINVAL;
1547                         break;
1548                 }
1549         }
1550         if (!result && !ima_validate_rule(entry))
1551                 result = -EINVAL;
1552         else if (entry->action == APPRAISE)
1553                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1554
1555         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1556                 template_desc = entry->template ? entry->template :
1557                                                   ima_template_desc_current();
1558                 check_template_modsig(template_desc);
1559         }
1560
1561         audit_log_format(ab, "res=%d", !result);
1562         audit_log_end(ab);
1563         return result;
1564 }
1565
1566 /**
1567  * ima_parse_add_rule - add a rule to ima_policy_rules
1568  * @rule - ima measurement policy rule
1569  *
1570  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1571  * Returns the length of the rule parsed, an error code on failure
1572  */
1573 ssize_t ima_parse_add_rule(char *rule)
1574 {
1575         static const char op[] = "update_policy";
1576         char *p;
1577         struct ima_rule_entry *entry;
1578         ssize_t result, len;
1579         int audit_info = 0;
1580
1581         p = strsep(&rule, "\n");
1582         len = strlen(p) + 1;
1583         p += strspn(p, " \t");
1584
1585         if (*p == '#' || *p == '\0')
1586                 return len;
1587
1588         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1589         if (!entry) {
1590                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1591                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1592                 return -ENOMEM;
1593         }
1594
1595         INIT_LIST_HEAD(&entry->list);
1596
1597         result = ima_parse_rule(p, entry);
1598         if (result) {
1599                 ima_free_rule(entry);
1600                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1601                                     NULL, op, "invalid-policy", result,
1602                                     audit_info);
1603                 return result;
1604         }
1605
1606         list_add_tail(&entry->list, &ima_temp_rules);
1607
1608         return len;
1609 }
1610
1611 /**
1612  * ima_delete_rules() called to cleanup invalid in-flight policy.
1613  * We don't need locking as we operate on the temp list, which is
1614  * different from the active one.  There is also only one user of
1615  * ima_delete_rules() at a time.
1616  */
1617 void ima_delete_rules(void)
1618 {
1619         struct ima_rule_entry *entry, *tmp;
1620
1621         temp_ima_appraise = 0;
1622         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1623                 list_del(&entry->list);
1624                 ima_free_rule(entry);
1625         }
1626 }
1627
1628 #define __ima_hook_stringify(func, str) (#func),
1629
1630 const char *const func_tokens[] = {
1631         __ima_hooks(__ima_hook_stringify)
1632 };
1633
1634 #ifdef  CONFIG_IMA_READ_POLICY
1635 enum {
1636         mask_exec = 0, mask_write, mask_read, mask_append
1637 };
1638
1639 static const char *const mask_tokens[] = {
1640         "^MAY_EXEC",
1641         "^MAY_WRITE",
1642         "^MAY_READ",
1643         "^MAY_APPEND"
1644 };
1645
1646 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1647 {
1648         loff_t l = *pos;
1649         struct ima_rule_entry *entry;
1650
1651         rcu_read_lock();
1652         list_for_each_entry_rcu(entry, ima_rules, list) {
1653                 if (!l--) {
1654                         rcu_read_unlock();
1655                         return entry;
1656                 }
1657         }
1658         rcu_read_unlock();
1659         return NULL;
1660 }
1661
1662 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1663 {
1664         struct ima_rule_entry *entry = v;
1665
1666         rcu_read_lock();
1667         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1668         rcu_read_unlock();
1669         (*pos)++;
1670
1671         return (&entry->list == ima_rules) ? NULL : entry;
1672 }
1673
1674 void ima_policy_stop(struct seq_file *m, void *v)
1675 {
1676 }
1677
1678 #define pt(token)       policy_tokens[token].pattern
1679 #define mt(token)       mask_tokens[token]
1680
1681 /*
1682  * policy_func_show - display the ima_hooks policy rule
1683  */
1684 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1685 {
1686         if (func > 0 && func < MAX_CHECK)
1687                 seq_printf(m, "func=%s ", func_tokens[func]);
1688         else
1689                 seq_printf(m, "func=%d ", func);
1690 }
1691
1692 static void ima_show_rule_opt_list(struct seq_file *m,
1693                                    const struct ima_rule_opt_list *opt_list)
1694 {
1695         size_t i;
1696
1697         for (i = 0; i < opt_list->count; i++)
1698                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
1699 }
1700
1701 int ima_policy_show(struct seq_file *m, void *v)
1702 {
1703         struct ima_rule_entry *entry = v;
1704         int i;
1705         char tbuf[64] = {0,};
1706         int offset = 0;
1707
1708         rcu_read_lock();
1709
1710         if (entry->action & MEASURE)
1711                 seq_puts(m, pt(Opt_measure));
1712         if (entry->action & DONT_MEASURE)
1713                 seq_puts(m, pt(Opt_dont_measure));
1714         if (entry->action & APPRAISE)
1715                 seq_puts(m, pt(Opt_appraise));
1716         if (entry->action & DONT_APPRAISE)
1717                 seq_puts(m, pt(Opt_dont_appraise));
1718         if (entry->action & AUDIT)
1719                 seq_puts(m, pt(Opt_audit));
1720         if (entry->action & HASH)
1721                 seq_puts(m, pt(Opt_hash));
1722         if (entry->action & DONT_HASH)
1723                 seq_puts(m, pt(Opt_dont_hash));
1724
1725         seq_puts(m, " ");
1726
1727         if (entry->flags & IMA_FUNC)
1728                 policy_func_show(m, entry->func);
1729
1730         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1731                 if (entry->flags & IMA_MASK)
1732                         offset = 1;
1733                 if (entry->mask & MAY_EXEC)
1734                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
1735                 if (entry->mask & MAY_WRITE)
1736                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
1737                 if (entry->mask & MAY_READ)
1738                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
1739                 if (entry->mask & MAY_APPEND)
1740                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
1741                 seq_puts(m, " ");
1742         }
1743
1744         if (entry->flags & IMA_FSMAGIC) {
1745                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
1746                 seq_printf(m, pt(Opt_fsmagic), tbuf);
1747                 seq_puts(m, " ");
1748         }
1749
1750         if (entry->flags & IMA_FSNAME) {
1751                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
1752                 seq_printf(m, pt(Opt_fsname), tbuf);
1753                 seq_puts(m, " ");
1754         }
1755
1756         if (entry->flags & IMA_KEYRINGS) {
1757                 seq_puts(m, "keyrings=");
1758                 ima_show_rule_opt_list(m, entry->keyrings);
1759                 seq_puts(m, " ");
1760         }
1761
1762         if (entry->flags & IMA_LABEL) {
1763                 seq_puts(m, "label=");
1764                 ima_show_rule_opt_list(m, entry->label);
1765                 seq_puts(m, " ");
1766         }
1767
1768         if (entry->flags & IMA_PCR) {
1769                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
1770                 seq_printf(m, pt(Opt_pcr), tbuf);
1771                 seq_puts(m, " ");
1772         }
1773
1774         if (entry->flags & IMA_FSUUID) {
1775                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
1776                 seq_puts(m, " ");
1777         }
1778
1779         if (entry->flags & IMA_UID) {
1780                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1781                 if (entry->uid_op == &uid_gt)
1782                         seq_printf(m, pt(Opt_uid_gt), tbuf);
1783                 else if (entry->uid_op == &uid_lt)
1784                         seq_printf(m, pt(Opt_uid_lt), tbuf);
1785                 else
1786                         seq_printf(m, pt(Opt_uid_eq), tbuf);
1787                 seq_puts(m, " ");
1788         }
1789
1790         if (entry->flags & IMA_EUID) {
1791                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1792                 if (entry->uid_op == &uid_gt)
1793                         seq_printf(m, pt(Opt_euid_gt), tbuf);
1794                 else if (entry->uid_op == &uid_lt)
1795                         seq_printf(m, pt(Opt_euid_lt), tbuf);
1796                 else
1797                         seq_printf(m, pt(Opt_euid_eq), tbuf);
1798                 seq_puts(m, " ");
1799         }
1800
1801         if (entry->flags & IMA_FOWNER) {
1802                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
1803                 if (entry->fowner_op == &uid_gt)
1804                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
1805                 else if (entry->fowner_op == &uid_lt)
1806                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
1807                 else
1808                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
1809                 seq_puts(m, " ");
1810         }
1811
1812         for (i = 0; i < MAX_LSM_RULES; i++) {
1813                 if (entry->lsm[i].rule) {
1814                         switch (i) {
1815                         case LSM_OBJ_USER:
1816                                 seq_printf(m, pt(Opt_obj_user),
1817                                            entry->lsm[i].args_p);
1818                                 break;
1819                         case LSM_OBJ_ROLE:
1820                                 seq_printf(m, pt(Opt_obj_role),
1821                                            entry->lsm[i].args_p);
1822                                 break;
1823                         case LSM_OBJ_TYPE:
1824                                 seq_printf(m, pt(Opt_obj_type),
1825                                            entry->lsm[i].args_p);
1826                                 break;
1827                         case LSM_SUBJ_USER:
1828                                 seq_printf(m, pt(Opt_subj_user),
1829                                            entry->lsm[i].args_p);
1830                                 break;
1831                         case LSM_SUBJ_ROLE:
1832                                 seq_printf(m, pt(Opt_subj_role),
1833                                            entry->lsm[i].args_p);
1834                                 break;
1835                         case LSM_SUBJ_TYPE:
1836                                 seq_printf(m, pt(Opt_subj_type),
1837                                            entry->lsm[i].args_p);
1838                                 break;
1839                         }
1840                         seq_puts(m, " ");
1841                 }
1842         }
1843         if (entry->template)
1844                 seq_printf(m, "template=%s ", entry->template->name);
1845         if (entry->flags & IMA_DIGSIG_REQUIRED) {
1846                 if (entry->flags & IMA_MODSIG_ALLOWED)
1847                         seq_puts(m, "appraise_type=imasig|modsig ");
1848                 else
1849                         seq_puts(m, "appraise_type=imasig ");
1850         }
1851         if (entry->flags & IMA_CHECK_BLACKLIST)
1852                 seq_puts(m, "appraise_flag=check_blacklist ");
1853         if (entry->flags & IMA_PERMIT_DIRECTIO)
1854                 seq_puts(m, "permit_directio ");
1855         rcu_read_unlock();
1856         seq_puts(m, "\n");
1857         return 0;
1858 }
1859 #endif  /* CONFIG_IMA_READ_POLICY */
1860
1861 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
1862 /*
1863  * ima_appraise_signature: whether IMA will appraise a given function using
1864  * an IMA digital signature. This is restricted to cases where the kernel
1865  * has a set of built-in trusted keys in order to avoid an attacker simply
1866  * loading additional keys.
1867  */
1868 bool ima_appraise_signature(enum kernel_read_file_id id)
1869 {
1870         struct ima_rule_entry *entry;
1871         bool found = false;
1872         enum ima_hooks func;
1873
1874         if (id >= READING_MAX_ID)
1875                 return false;
1876
1877         func = read_idmap[id] ?: FILE_CHECK;
1878
1879         rcu_read_lock();
1880         list_for_each_entry_rcu(entry, ima_rules, list) {
1881                 if (entry->action != APPRAISE)
1882                         continue;
1883
1884                 /*
1885                  * A generic entry will match, but otherwise require that it
1886                  * match the func we're looking for
1887                  */
1888                 if (entry->func && entry->func != func)
1889                         continue;
1890
1891                 /*
1892                  * We require this to be a digital signature, not a raw IMA
1893                  * hash.
1894                  */
1895                 if (entry->flags & IMA_DIGSIG_REQUIRED)
1896                         found = true;
1897
1898                 /*
1899                  * We've found a rule that matches, so break now even if it
1900                  * didn't require a digital signature - a later rule that does
1901                  * won't override it, so would be a false positive.
1902                  */
1903                 break;
1904         }
1905
1906         rcu_read_unlock();
1907         return found;
1908 }
1909 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */