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                         break;
 603                 default:
 604                         break;
 605                 }
 606                 if (!rc)
 607                         return false;
 608         }
 609         return true;
 610 }
 611
 612 /*
 613  * In addition to knowing that we need to appraise the file in general,
 614  * we need to differentiate between calling hooks, for hook specific rules.
 615  */
 616 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
 617 {
 618         if (!(rule->flags & IMA_FUNC))
 619                 return IMA_FILE_APPRAISE;
 620
 621         switch (func) {
 622         case MMAP_CHECK:
 623                 return IMA_MMAP_APPRAISE;
 624         case BPRM_CHECK:
 625                 return IMA_BPRM_APPRAISE;
 626         case CREDS_CHECK:
 627                 return IMA_CREDS_APPRAISE;
 628         case FILE_CHECK:
 629         case POST_SETATTR:
 630                 return IMA_FILE_APPRAISE;
 631         case MODULE_CHECK ... MAX_CHECK - 1:
 632         default:
 633                 return IMA_READ_APPRAISE;
 634         }
 635 }
 636
 637 /**
 638  * ima_match_policy - decision based on LSM and other conditions
 639  * @mnt_userns: user namespace of the mount the inode was found from
 640  * @inode: pointer to an inode for which the policy decision is being made
 641  * @cred: pointer to a credentials structure for which the policy decision is
 642  *        being made
 643  * @secid: LSM secid of the task to be validated
 644  * @func: IMA hook identifier
 645  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 646  * @pcr: set the pcr to extend
 647  * @template_desc: the template that should be used for this rule
 648  * @func_data: func specific data, may be NULL
 649  *
 650  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 651  * conditions.
 652  *
 653  * Since the IMA policy may be updated multiple times we need to lock the
 654  * list when walking it.  Reads are many orders of magnitude more numerous
 655  * than writes so ima_match_policy() is classical RCU candidate.
 656  */
 657 int ima_match_policy(struct user_namespace *mnt_userns, struct inode *inode,
 658                      const struct cred *cred, u32 secid, enum ima_hooks func,
 659                      int mask, int flags, int *pcr,
 660                      struct ima_template_desc **template_desc,
 661                      const char *func_data)
 662 {
 663         struct ima_rule_entry *entry;
 664         int action = 0, actmask = flags | (flags << 1);
 665
 666         if (template_desc && !*template_desc)
 667                 *template_desc = ima_template_desc_current();
 668
 669         rcu_read_lock();
 670         list_for_each_entry_rcu(entry, ima_rules, list) {
 671
 672                 if (!(entry->action & actmask))
 673                         continue;
 674
 675                 if (!ima_match_rules(entry, mnt_userns, inode, cred, secid,
 676                                      func, mask, func_data))
 677                         continue;
 678
 679                 action |= entry->flags & IMA_ACTION_FLAGS;
 680
 681                 action |= entry->action & IMA_DO_MASK;
 682                 if (entry->action & IMA_APPRAISE) {
 683                         action |= get_subaction(entry, func);
 684                         action &= ~IMA_HASH;
 685                         if (ima_fail_unverifiable_sigs)
 686                                 action |= IMA_FAIL_UNVERIFIABLE_SIGS;
 687                 }
 688
 689
 690                 if (entry->action & IMA_DO_MASK)
 691                         actmask &= ~(entry->action | entry->action << 1);
 692                 else
 693                         actmask &= ~(entry->action | entry->action >> 1);
 694
 695                 if ((pcr) && (entry->flags & IMA_PCR))
 696                         *pcr = entry->pcr;
 697
 698                 if (template_desc && entry->template)
 699                         *template_desc = entry->template;
 700
 701                 if (!actmask)
 702                         break;
 703         }
 704         rcu_read_unlock();
 705
 706         return action;
 707 }
 708
 709 /*
 710  * Initialize the ima_policy_flag variable based on the currently
 711  * loaded policy.  Based on this flag, the decision to short circuit
 712  * out of a function or not call the function in the first place
 713  * can be made earlier.
 714  */
 715 void ima_update_policy_flag(void)
 716 {
 717         struct ima_rule_entry *entry;
 718
 719         list_for_each_entry(entry, ima_rules, list) {
 720                 if (entry->action & IMA_DO_MASK)
 721                         ima_policy_flag |= entry->action;
 722         }
 723
 724         ima_appraise |= (build_ima_appraise | temp_ima_appraise);
 725         if (!ima_appraise)
 726                 ima_policy_flag &= ~IMA_APPRAISE;
 727 }
 728
 729 static int ima_appraise_flag(enum ima_hooks func)
 730 {
 731         if (func == MODULE_CHECK)
 732                 return IMA_APPRAISE_MODULES;
 733         else if (func == FIRMWARE_CHECK)
 734                 return IMA_APPRAISE_FIRMWARE;
 735         else if (func == POLICY_CHECK)
 736                 return IMA_APPRAISE_POLICY;
 737         else if (func == KEXEC_KERNEL_CHECK)
 738                 return IMA_APPRAISE_KEXEC;
 739         return 0;
 740 }
 741
 742 static void add_rules(struct ima_rule_entry *entries, int count,
 743                       enum policy_rule_list policy_rule)
 744 {
 745         int i = 0;
 746
 747         for (i = 0; i < count; i++) {
 748                 struct ima_rule_entry *entry;
 749
 750                 if (policy_rule & IMA_DEFAULT_POLICY)
 751                         list_add_tail(&entries[i].list, &ima_default_rules);
 752
 753                 if (policy_rule & IMA_CUSTOM_POLICY) {
 754                         entry = kmemdup(&entries[i], sizeof(*entry),
 755                                         GFP_KERNEL);
 756                         if (!entry)
 757                                 continue;
 758
 759                         list_add_tail(&entry->list, &ima_policy_rules);
 760                 }
 761                 if (entries[i].action == APPRAISE) {
 762                         if (entries != build_appraise_rules)
 763                                 temp_ima_appraise |=
 764                                         ima_appraise_flag(entries[i].func);
 765                         else
 766                                 build_ima_appraise |=
 767                                         ima_appraise_flag(entries[i].func);
 768                 }
 769         }
 770 }
 771
 772 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry);
 773
 774 static int __init ima_init_arch_policy(void)
 775 {
 776         const char * const *arch_rules;
 777         const char * const *rules;
 778         int arch_entries = 0;
 779         int i = 0;
 780
 781         arch_rules = arch_get_ima_policy();
 782         if (!arch_rules)
 783                 return arch_entries;
 784
 785         /* Get number of rules */
 786         for (rules = arch_rules; *rules != NULL; rules++)
 787                 arch_entries++;
 788
 789         arch_policy_entry = kcalloc(arch_entries + 1,
 790                                     sizeof(*arch_policy_entry), GFP_KERNEL);
 791         if (!arch_policy_entry)
 792                 return 0;
 793
 794         /* Convert each policy string rules to struct ima_rule_entry format */
 795         for (rules = arch_rules, i = 0; *rules != NULL; rules++) {
 796                 char rule[255];
 797                 int result;
 798
 799                 result = strlcpy(rule, *rules, sizeof(rule));
 800
 801                 INIT_LIST_HEAD(&arch_policy_entry[i].list);
 802                 result = ima_parse_rule(rule, &arch_policy_entry[i]);
 803                 if (result) {
 804                         pr_warn("Skipping unknown architecture policy rule: %s\n",
 805                                 rule);
 806                         memset(&arch_policy_entry[i], 0,
 807                                sizeof(*arch_policy_entry));
 808                         continue;
 809                 }
 810                 i++;
 811         }
 812         return i;
 813 }
 814
 815 /**
 816  * ima_init_policy - initialize the default measure rules.
 817  *
 818  * ima_rules points to either the ima_default_rules or the
 819  * the new ima_policy_rules.
 820  */
 821 void __init ima_init_policy(void)
 822 {
 823         int build_appraise_entries, arch_entries;
 824
 825         /* if !ima_policy, we load NO default rules */
 826         if (ima_policy)
 827                 add_rules(dont_measure_rules, ARRAY_SIZE(dont_measure_rules),
 828                           IMA_DEFAULT_POLICY);
 829
 830         switch (ima_policy) {
 831         case ORIGINAL_TCB:
 832                 add_rules(original_measurement_rules,
 833                           ARRAY_SIZE(original_measurement_rules),
 834                           IMA_DEFAULT_POLICY);
 835                 break;
 836         case DEFAULT_TCB:
 837                 add_rules(default_measurement_rules,
 838                           ARRAY_SIZE(default_measurement_rules),
 839                           IMA_DEFAULT_POLICY);
 840                 break;
 841         default:
 842                 break;
 843         }
 844
 845         /*
 846          * Based on runtime secure boot flags, insert arch specific measurement
 847          * and appraise rules requiring file signatures for both the initial
 848          * and custom policies, prior to other appraise rules.
 849          * (Highest priority)
 850          */
 851         arch_entries = ima_init_arch_policy();
 852         if (!arch_entries)
 853                 pr_info("No architecture policies found\n");
 854         else
 855                 add_rules(arch_policy_entry, arch_entries,
 856                           IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 857
 858         /*
 859          * Insert the builtin "secure_boot" policy rules requiring file
 860          * signatures, prior to other appraise rules.
 861          */
 862         if (ima_use_secure_boot)
 863                 add_rules(secure_boot_rules, ARRAY_SIZE(secure_boot_rules),
 864                           IMA_DEFAULT_POLICY);
 865
 866         /*
 867          * Insert the build time appraise rules requiring file signatures
 868          * for both the initial and custom policies, prior to other appraise
 869          * rules. As the secure boot rules includes all of the build time
 870          * rules, include either one or the other set of rules, but not both.
 871          */
 872         build_appraise_entries = ARRAY_SIZE(build_appraise_rules);
 873         if (build_appraise_entries) {
 874                 if (ima_use_secure_boot)
 875                         add_rules(build_appraise_rules, build_appraise_entries,
 876                                   IMA_CUSTOM_POLICY);
 877                 else
 878                         add_rules(build_appraise_rules, build_appraise_entries,
 879                                   IMA_DEFAULT_POLICY | IMA_CUSTOM_POLICY);
 880         }
 881
 882         if (ima_use_appraise_tcb)
 883                 add_rules(default_appraise_rules,
 884                           ARRAY_SIZE(default_appraise_rules),
 885                           IMA_DEFAULT_POLICY);
 886
 887         if (ima_use_critical_data)
 888                 add_rules(critical_data_rules,
 889                           ARRAY_SIZE(critical_data_rules),
 890                           IMA_DEFAULT_POLICY);
 891
 892         ima_update_policy_flag();
 893 }
 894
 895 /* Make sure we have a valid policy, at least containing some rules. */
 896 int ima_check_policy(void)
 897 {
 898         if (list_empty(&ima_temp_rules))
 899                 return -EINVAL;
 900         return 0;
 901 }
 902
 903 /**
 904  * ima_update_policy - update default_rules with new measure rules
 905  *
 906  * Called on file .release to update the default rules with a complete new
 907  * policy.  What we do here is to splice ima_policy_rules and ima_temp_rules so
 908  * they make a queue.  The policy may be updated multiple times and this is the
 909  * RCU updater.
 910  *
 911  * Policy rules are never deleted so ima_policy_flag gets zeroed only once when
 912  * we switch from the default policy to user defined.
 913  */
 914 void ima_update_policy(void)
 915 {
 916         struct list_head *policy = &ima_policy_rules;
 917
 918         list_splice_tail_init_rcu(&ima_temp_rules, policy, synchronize_rcu);
 919
 920         if (ima_rules != policy) {
 921                 ima_policy_flag = 0;
 922                 ima_rules = policy;
 923
 924                 /*
 925                  * IMA architecture specific policy rules are specified
 926                  * as strings and converted to an array of ima_entry_rules
 927                  * on boot.  After loading a custom policy, free the
 928                  * architecture specific rules stored as an array.
 929                  */
 930                 kfree(arch_policy_entry);
 931         }
 932         ima_update_policy_flag();
 933
 934         /* Custom IMA policy has been loaded */
 935         ima_process_queued_keys();
 936 }
 937
 938 /* Keep the enumeration in sync with the policy_tokens! */
 939 enum {
 940         Opt_measure, Opt_dont_measure,
 941         Opt_appraise, Opt_dont_appraise,
 942         Opt_audit, Opt_hash, Opt_dont_hash,
 943         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 944         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 945         Opt_func, Opt_mask, Opt_fsmagic, Opt_fsname,
 946         Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
 947         Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 948         Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
 949         Opt_appraise_type, Opt_appraise_flag,
 950         Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings,
 951         Opt_label, Opt_err
 952 };
 953
 954 static const match_table_t policy_tokens = {
 955         {Opt_measure, "measure"},
 956         {Opt_dont_measure, "dont_measure"},
 957         {Opt_appraise, "appraise"},
 958         {Opt_dont_appraise, "dont_appraise"},
 959         {Opt_audit, "audit"},
 960         {Opt_hash, "hash"},
 961         {Opt_dont_hash, "dont_hash"},
 962         {Opt_obj_user, "obj_user=%s"},
 963         {Opt_obj_role, "obj_role=%s"},
 964         {Opt_obj_type, "obj_type=%s"},
 965         {Opt_subj_user, "subj_user=%s"},
 966         {Opt_subj_role, "subj_role=%s"},
 967         {Opt_subj_type, "subj_type=%s"},
 968         {Opt_func, "func=%s"},
 969         {Opt_mask, "mask=%s"},
 970         {Opt_fsmagic, "fsmagic=%s"},
 971         {Opt_fsname, "fsname=%s"},
 972         {Opt_fsuuid, "fsuuid=%s"},
 973         {Opt_uid_eq, "uid=%s"},
 974         {Opt_euid_eq, "euid=%s"},
 975         {Opt_fowner_eq, "fowner=%s"},
 976         {Opt_uid_gt, "uid>%s"},
 977         {Opt_euid_gt, "euid>%s"},
 978         {Opt_fowner_gt, "fowner>%s"},
 979         {Opt_uid_lt, "uid<%s"},
 980         {Opt_euid_lt, "euid<%s"},
 981         {Opt_fowner_lt, "fowner<%s"},
 982         {Opt_appraise_type, "appraise_type=%s"},
 983         {Opt_appraise_flag, "appraise_flag=%s"},
 984         {Opt_permit_directio, "permit_directio"},
 985         {Opt_pcr, "pcr=%s"},
 986         {Opt_template, "template=%s"},
 987         {Opt_keyrings, "keyrings=%s"},
 988         {Opt_label, "label=%s"},
 989         {Opt_err, NULL}
 990 };
 991
 992 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 993                              substring_t *args, int lsm_rule, int audit_type)
 994 {
 995         int result;
 996
 997         if (entry->lsm[lsm_rule].rule)
 998                 return -EINVAL;
 999
1000         entry->lsm[lsm_rule].args_p = match_strdup(args);
1001         if (!entry->lsm[lsm_rule].args_p)
1002                 return -ENOMEM;
1003
1004         entry->lsm[lsm_rule].type = audit_type;
1005         result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal,
1006                                       entry->lsm[lsm_rule].args_p,
1007                                       &entry->lsm[lsm_rule].rule);
1008         if (!entry->lsm[lsm_rule].rule) {
1009                 pr_warn("rule for LSM \'%s\' is undefined\n",
1010                         entry->lsm[lsm_rule].args_p);
1011
1012                 if (ima_rules == &ima_default_rules) {
1013                         kfree(entry->lsm[lsm_rule].args_p);
1014                         entry->lsm[lsm_rule].args_p = NULL;
1015                         result = -EINVAL;
1016                 } else
1017                         result = 0;
1018         }
1019
1020         return result;
1021 }
1022
1023 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
1024                               bool (*rule_operator)(kuid_t, kuid_t))
1025 {
1026         if (!ab)
1027                 return;
1028
1029         if (rule_operator == &uid_gt)
1030                 audit_log_format(ab, "%s>", key);
1031         else if (rule_operator == &uid_lt)
1032                 audit_log_format(ab, "%s<", key);
1033         else
1034                 audit_log_format(ab, "%s=", key);
1035         audit_log_format(ab, "%s ", value);
1036 }
1037 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
1038 {
1039         ima_log_string_op(ab, key, value, NULL);
1040 }
1041
1042 /*
1043  * Validating the appended signature included in the measurement list requires
1044  * the file hash calculated without the appended signature (i.e., the 'd-modsig'
1045  * field). Therefore, notify the user if they have the 'modsig' field but not
1046  * the 'd-modsig' field in the template.
1047  */
1048 static void check_template_modsig(const struct ima_template_desc *template)
1049 {
1050 #define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
1051         bool has_modsig, has_dmodsig;
1052         static bool checked;
1053         int i;
1054
1055         /* We only need to notify the user once. */
1056         if (checked)
1057                 return;
1058
1059         has_modsig = has_dmodsig = false;
1060         for (i = 0; i < template->num_fields; i++) {
1061                 if (!strcmp(template->fields[i]->field_id, "modsig"))
1062                         has_modsig = true;
1063                 else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
1064                         has_dmodsig = true;
1065         }
1066
1067         if (has_modsig && !has_dmodsig)
1068                 pr_notice(MSG);
1069
1070         checked = true;
1071 #undef MSG
1072 }
1073
1074 static bool ima_validate_rule(struct ima_rule_entry *entry)
1075 {
1076         /* Ensure that the action is set and is compatible with the flags */
1077         if (entry->action == UNKNOWN)
1078                 return false;
1079
1080         if (entry->action != MEASURE && entry->flags & IMA_PCR)
1081                 return false;
1082
1083         if (entry->action != APPRAISE &&
1084             entry->flags & (IMA_DIGSIG_REQUIRED | IMA_MODSIG_ALLOWED | IMA_CHECK_BLACKLIST))
1085                 return false;
1086
1087         /*
1088          * The IMA_FUNC bit must be set if and only if there's a valid hook
1089          * function specified, and vice versa. Enforcing this property allows
1090          * for the NONE case below to validate a rule without an explicit hook
1091          * function.
1092          */
1093         if (((entry->flags & IMA_FUNC) && entry->func == NONE) ||
1094             (!(entry->flags & IMA_FUNC) && entry->func != NONE))
1095                 return false;
1096
1097         /*
1098          * Ensure that the hook function is compatible with the other
1099          * components of the rule
1100          */
1101         switch (entry->func) {
1102         case NONE:
1103         case FILE_CHECK:
1104         case MMAP_CHECK:
1105         case BPRM_CHECK:
1106         case CREDS_CHECK:
1107         case POST_SETATTR:
1108         case FIRMWARE_CHECK:
1109         case POLICY_CHECK:
1110                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1111                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1112                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1113                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1114                                      IMA_PERMIT_DIRECTIO))
1115                         return false;
1116
1117                 break;
1118         case MODULE_CHECK:
1119         case KEXEC_KERNEL_CHECK:
1120         case KEXEC_INITRAMFS_CHECK:
1121                 if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
1122                                      IMA_UID | IMA_FOWNER | IMA_FSUUID |
1123                                      IMA_INMASK | IMA_EUID | IMA_PCR |
1124                                      IMA_FSNAME | IMA_DIGSIG_REQUIRED |
1125                                      IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
1126                                      IMA_CHECK_BLACKLIST))
1127                         return false;
1128
1129                 break;
1130         case KEXEC_CMDLINE:
1131                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1132                         return false;
1133
1134                 if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID |
1135                                      IMA_FOWNER | IMA_FSUUID | IMA_EUID |
1136                                      IMA_PCR | IMA_FSNAME))
1137                         return false;
1138
1139                 break;
1140         case KEY_CHECK:
1141                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1142                         return false;
1143
1144                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1145                                      IMA_KEYRINGS))
1146                         return false;
1147
1148                 if (ima_rule_contains_lsm_cond(entry))
1149                         return false;
1150
1151                 break;
1152         case CRITICAL_DATA:
1153                 if (entry->action & ~(MEASURE | DONT_MEASURE))
1154                         return false;
1155
1156                 if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR |
1157                                      IMA_LABEL))
1158                         return false;
1159
1160                 if (ima_rule_contains_lsm_cond(entry))
1161                         return false;
1162
1163                 break;
1164         default:
1165                 return false;
1166         }
1167
1168         /* Ensure that combinations of flags are compatible with each other */
1169         if (entry->flags & IMA_CHECK_BLACKLIST &&
1170             !(entry->flags & IMA_MODSIG_ALLOWED))
1171                 return false;
1172
1173         return true;
1174 }
1175
1176 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
1177 {
1178         struct audit_buffer *ab;
1179         char *from;
1180         char *p;
1181         bool uid_token;
1182         struct ima_template_desc *template_desc;
1183         int result = 0;
1184
1185         ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
1186                                        AUDIT_INTEGRITY_POLICY_RULE);
1187
1188         entry->uid = INVALID_UID;
1189         entry->fowner = INVALID_UID;
1190         entry->uid_op = &uid_eq;
1191         entry->fowner_op = &uid_eq;
1192         entry->action = UNKNOWN;
1193         while ((p = strsep(&rule, " \t")) != NULL) {
1194                 substring_t args[MAX_OPT_ARGS];
1195                 int token;
1196                 unsigned long lnum;
1197
1198                 if (result < 0)
1199                         break;
1200                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
1201                         continue;
1202                 token = match_token(p, policy_tokens, args);
1203                 switch (token) {
1204                 case Opt_measure:
1205                         ima_log_string(ab, "action", "measure");
1206
1207                         if (entry->action != UNKNOWN)
1208                                 result = -EINVAL;
1209
1210                         entry->action = MEASURE;
1211                         break;
1212                 case Opt_dont_measure:
1213                         ima_log_string(ab, "action", "dont_measure");
1214
1215                         if (entry->action != UNKNOWN)
1216                                 result = -EINVAL;
1217
1218                         entry->action = DONT_MEASURE;
1219                         break;
1220                 case Opt_appraise:
1221                         ima_log_string(ab, "action", "appraise");
1222
1223                         if (entry->action != UNKNOWN)
1224                                 result = -EINVAL;
1225
1226                         entry->action = APPRAISE;
1227                         break;
1228                 case Opt_dont_appraise:
1229                         ima_log_string(ab, "action", "dont_appraise");
1230
1231                         if (entry->action != UNKNOWN)
1232                                 result = -EINVAL;
1233
1234                         entry->action = DONT_APPRAISE;
1235                         break;
1236                 case Opt_audit:
1237                         ima_log_string(ab, "action", "audit");
1238
1239                         if (entry->action != UNKNOWN)
1240                                 result = -EINVAL;
1241
1242                         entry->action = AUDIT;
1243                         break;
1244                 case Opt_hash:
1245                         ima_log_string(ab, "action", "hash");
1246
1247                         if (entry->action != UNKNOWN)
1248                                 result = -EINVAL;
1249
1250                         entry->action = HASH;
1251                         break;
1252                 case Opt_dont_hash:
1253                         ima_log_string(ab, "action", "dont_hash");
1254
1255                         if (entry->action != UNKNOWN)
1256                                 result = -EINVAL;
1257
1258                         entry->action = DONT_HASH;
1259                         break;
1260                 case Opt_func:
1261                         ima_log_string(ab, "func", args[0].from);
1262
1263                         if (entry->func)
1264                                 result = -EINVAL;
1265
1266                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
1267                                 entry->func = FILE_CHECK;
1268                         /* PATH_CHECK is for backwards compat */
1269                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
1270                                 entry->func = FILE_CHECK;
1271                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
1272                                 entry->func = MODULE_CHECK;
1273                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
1274                                 entry->func = FIRMWARE_CHECK;
1275                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
1276                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
1277                                 entry->func = MMAP_CHECK;
1278                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
1279                                 entry->func = BPRM_CHECK;
1280                         else if (strcmp(args[0].from, "CREDS_CHECK") == 0)
1281                                 entry->func = CREDS_CHECK;
1282                         else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") ==
1283                                  0)
1284                                 entry->func = KEXEC_KERNEL_CHECK;
1285                         else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
1286                                  == 0)
1287                                 entry->func = KEXEC_INITRAMFS_CHECK;
1288                         else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
1289                                 entry->func = POLICY_CHECK;
1290                         else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
1291                                 entry->func = KEXEC_CMDLINE;
1292                         else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) &&
1293                                  strcmp(args[0].from, "KEY_CHECK") == 0)
1294                                 entry->func = KEY_CHECK;
1295                         else if (strcmp(args[0].from, "CRITICAL_DATA") == 0)
1296                                 entry->func = CRITICAL_DATA;
1297                         else
1298                                 result = -EINVAL;
1299                         if (!result)
1300                                 entry->flags |= IMA_FUNC;
1301                         break;
1302                 case Opt_mask:
1303                         ima_log_string(ab, "mask", args[0].from);
1304
1305                         if (entry->mask)
1306                                 result = -EINVAL;
1307
1308                         from = args[0].from;
1309                         if (*from == '^')
1310                                 from++;
1311
1312                         if ((strcmp(from, "MAY_EXEC")) == 0)
1313                                 entry->mask = MAY_EXEC;
1314                         else if (strcmp(from, "MAY_WRITE") == 0)
1315                                 entry->mask = MAY_WRITE;
1316                         else if (strcmp(from, "MAY_READ") == 0)
1317                                 entry->mask = MAY_READ;
1318                         else if (strcmp(from, "MAY_APPEND") == 0)
1319                                 entry->mask = MAY_APPEND;
1320                         else
1321                                 result = -EINVAL;
1322                         if (!result)
1323                                 entry->flags |= (*args[0].from == '^')
1324                                      ? IMA_INMASK : IMA_MASK;
1325                         break;
1326                 case Opt_fsmagic:
1327                         ima_log_string(ab, "fsmagic", args[0].from);
1328
1329                         if (entry->fsmagic) {
1330                                 result = -EINVAL;
1331                                 break;
1332                         }
1333
1334                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
1335                         if (!result)
1336                                 entry->flags |= IMA_FSMAGIC;
1337                         break;
1338                 case Opt_fsname:
1339                         ima_log_string(ab, "fsname", args[0].from);
1340
1341                         entry->fsname = kstrdup(args[0].from, GFP_KERNEL);
1342                         if (!entry->fsname) {
1343                                 result = -ENOMEM;
1344                                 break;
1345                         }
1346                         result = 0;
1347                         entry->flags |= IMA_FSNAME;
1348                         break;
1349                 case Opt_keyrings:
1350                         ima_log_string(ab, "keyrings", args[0].from);
1351
1352                         if (!IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) ||
1353                             entry->keyrings) {
1354                                 result = -EINVAL;
1355                                 break;
1356                         }
1357
1358                         entry->keyrings = ima_alloc_rule_opt_list(args);
1359                         if (IS_ERR(entry->keyrings)) {
1360                                 result = PTR_ERR(entry->keyrings);
1361                                 entry->keyrings = NULL;
1362                                 break;
1363                         }
1364
1365                         entry->flags |= IMA_KEYRINGS;
1366                         break;
1367                 case Opt_label:
1368                         ima_log_string(ab, "label", args[0].from);
1369
1370                         if (entry->label) {
1371                                 result = -EINVAL;
1372                                 break;
1373                         }
1374
1375                         entry->label = ima_alloc_rule_opt_list(args);
1376                         if (IS_ERR(entry->label)) {
1377                                 result = PTR_ERR(entry->label);
1378                                 entry->label = NULL;
1379                                 break;
1380                         }
1381
1382                         entry->flags |= IMA_LABEL;
1383                         break;
1384                 case Opt_fsuuid:
1385                         ima_log_string(ab, "fsuuid", args[0].from);
1386
1387                         if (!uuid_is_null(&entry->fsuuid)) {
1388                                 result = -EINVAL;
1389                                 break;
1390                         }
1391
1392                         result = uuid_parse(args[0].from, &entry->fsuuid);
1393                         if (!result)
1394                                 entry->flags |= IMA_FSUUID;
1395                         break;
1396                 case Opt_uid_gt:
1397                 case Opt_euid_gt:
1398                         entry->uid_op = &uid_gt;
1399                         fallthrough;
1400                 case Opt_uid_lt:
1401                 case Opt_euid_lt:
1402                         if ((token == Opt_uid_lt) || (token == Opt_euid_lt))
1403                                 entry->uid_op = &uid_lt;
1404                         fallthrough;
1405                 case Opt_uid_eq:
1406                 case Opt_euid_eq:
1407                         uid_token = (token == Opt_uid_eq) ||
1408                                     (token == Opt_uid_gt) ||
1409                                     (token == Opt_uid_lt);
1410
1411                         ima_log_string_op(ab, uid_token ? "uid" : "euid",
1412                                           args[0].from, entry->uid_op);
1413
1414                         if (uid_valid(entry->uid)) {
1415                                 result = -EINVAL;
1416                                 break;
1417                         }
1418
1419                         result = kstrtoul(args[0].from, 10, &lnum);
1420                         if (!result) {
1421                                 entry->uid = make_kuid(current_user_ns(),
1422                                                        (uid_t) lnum);
1423                                 if (!uid_valid(entry->uid) ||
1424                                     (uid_t)lnum != lnum)
1425                                         result = -EINVAL;
1426                                 else
1427                                         entry->flags |= uid_token
1428                                             ? IMA_UID : IMA_EUID;
1429                         }
1430                         break;
1431                 case Opt_fowner_gt:
1432                         entry->fowner_op = &uid_gt;
1433                         fallthrough;
1434                 case Opt_fowner_lt:
1435                         if (token == Opt_fowner_lt)
1436                                 entry->fowner_op = &uid_lt;
1437                         fallthrough;
1438                 case Opt_fowner_eq:
1439                         ima_log_string_op(ab, "fowner", args[0].from,
1440                                           entry->fowner_op);
1441
1442                         if (uid_valid(entry->fowner)) {
1443                                 result = -EINVAL;
1444                                 break;
1445                         }
1446
1447                         result = kstrtoul(args[0].from, 10, &lnum);
1448                         if (!result) {
1449                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
1450                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
1451                                         result = -EINVAL;
1452                                 else
1453                                         entry->flags |= IMA_FOWNER;
1454                         }
1455                         break;
1456                 case Opt_obj_user:
1457                         ima_log_string(ab, "obj_user", args[0].from);
1458                         result = ima_lsm_rule_init(entry, args,
1459                                                    LSM_OBJ_USER,
1460                                                    AUDIT_OBJ_USER);
1461                         break;
1462                 case Opt_obj_role:
1463                         ima_log_string(ab, "obj_role", args[0].from);
1464                         result = ima_lsm_rule_init(entry, args,
1465                                                    LSM_OBJ_ROLE,
1466                                                    AUDIT_OBJ_ROLE);
1467                         break;
1468                 case Opt_obj_type:
1469                         ima_log_string(ab, "obj_type", args[0].from);
1470                         result = ima_lsm_rule_init(entry, args,
1471                                                    LSM_OBJ_TYPE,
1472                                                    AUDIT_OBJ_TYPE);
1473                         break;
1474                 case Opt_subj_user:
1475                         ima_log_string(ab, "subj_user", args[0].from);
1476                         result = ima_lsm_rule_init(entry, args,
1477                                                    LSM_SUBJ_USER,
1478                                                    AUDIT_SUBJ_USER);
1479                         break;
1480                 case Opt_subj_role:
1481                         ima_log_string(ab, "subj_role", args[0].from);
1482                         result = ima_lsm_rule_init(entry, args,
1483                                                    LSM_SUBJ_ROLE,
1484                                                    AUDIT_SUBJ_ROLE);
1485                         break;
1486                 case Opt_subj_type:
1487                         ima_log_string(ab, "subj_type", args[0].from);
1488                         result = ima_lsm_rule_init(entry, args,
1489                                                    LSM_SUBJ_TYPE,
1490                                                    AUDIT_SUBJ_TYPE);
1491                         break;
1492                 case Opt_appraise_type:
1493                         ima_log_string(ab, "appraise_type", args[0].from);
1494                         if ((strcmp(args[0].from, "imasig")) == 0)
1495                                 entry->flags |= IMA_DIGSIG_REQUIRED;
1496                         else if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1497                                  strcmp(args[0].from, "imasig|modsig") == 0)
1498                                 entry->flags |= IMA_DIGSIG_REQUIRED |
1499                                                 IMA_MODSIG_ALLOWED;
1500                         else
1501                                 result = -EINVAL;
1502                         break;
1503                 case Opt_appraise_flag:
1504                         ima_log_string(ab, "appraise_flag", args[0].from);
1505                         if (IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG) &&
1506                             strstr(args[0].from, "blacklist"))
1507                                 entry->flags |= IMA_CHECK_BLACKLIST;
1508                         else
1509                                 result = -EINVAL;
1510                         break;
1511                 case Opt_permit_directio:
1512                         entry->flags |= IMA_PERMIT_DIRECTIO;
1513                         break;
1514                 case Opt_pcr:
1515                         ima_log_string(ab, "pcr", args[0].from);
1516
1517                         result = kstrtoint(args[0].from, 10, &entry->pcr);
1518                         if (result || INVALID_PCR(entry->pcr))
1519                                 result = -EINVAL;
1520                         else
1521                                 entry->flags |= IMA_PCR;
1522
1523                         break;
1524                 case Opt_template:
1525                         ima_log_string(ab, "template", args[0].from);
1526                         if (entry->action != MEASURE) {
1527                                 result = -EINVAL;
1528                                 break;
1529                         }
1530                         template_desc = lookup_template_desc(args[0].from);
1531                         if (!template_desc || entry->template) {
1532                                 result = -EINVAL;
1533                                 break;
1534                         }
1535
1536                         /*
1537                          * template_desc_init_fields() does nothing if
1538                          * the template is already initialised, so
1539                          * it's safe to do this unconditionally
1540                          */
1541                         template_desc_init_fields(template_desc->fmt,
1542                                                  &(template_desc->fields),
1543                                                  &(template_desc->num_fields));
1544                         entry->template = template_desc;
1545                         break;
1546                 case Opt_err:
1547                         ima_log_string(ab, "UNKNOWN", p);
1548                         result = -EINVAL;
1549                         break;
1550                 }
1551         }
1552         if (!result && !ima_validate_rule(entry))
1553                 result = -EINVAL;
1554         else if (entry->action == APPRAISE)
1555                 temp_ima_appraise |= ima_appraise_flag(entry->func);
1556
1557         if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
1558                 template_desc = entry->template ? entry->template :
1559                                                   ima_template_desc_current();
1560                 check_template_modsig(template_desc);
1561         }
1562
1563         audit_log_format(ab, "res=%d", !result);
1564         audit_log_end(ab);
1565         return result;
1566 }
1567
1568 /**
1569  * ima_parse_add_rule - add a rule to ima_policy_rules
1570  * @rule - ima measurement policy rule
1571  *
1572  * Avoid locking by allowing just one writer at a time in ima_write_policy()
1573  * Returns the length of the rule parsed, an error code on failure
1574  */
1575 ssize_t ima_parse_add_rule(char *rule)
1576 {
1577         static const char op[] = "update_policy";
1578         char *p;
1579         struct ima_rule_entry *entry;
1580         ssize_t result, len;
1581         int audit_info = 0;
1582
1583         p = strsep(&rule, "\n");
1584         len = strlen(p) + 1;
1585         p += strspn(p, " \t");
1586
1587         if (*p == '#' || *p == '\0')
1588                 return len;
1589
1590         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1591         if (!entry) {
1592                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1593                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
1594                 return -ENOMEM;
1595         }
1596
1597         INIT_LIST_HEAD(&entry->list);
1598
1599         result = ima_parse_rule(p, entry);
1600         if (result) {
1601                 ima_free_rule(entry);
1602                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
1603                                     NULL, op, "invalid-policy", result,
1604                                     audit_info);
1605                 return result;
1606         }
1607
1608         list_add_tail(&entry->list, &ima_temp_rules);
1609
1610         return len;
1611 }
1612
1613 /**
1614  * ima_delete_rules() called to cleanup invalid in-flight policy.
1615  * We don't need locking as we operate on the temp list, which is
1616  * different from the active one.  There is also only one user of
1617  * ima_delete_rules() at a time.
1618  */
1619 void ima_delete_rules(void)
1620 {
1621         struct ima_rule_entry *entry, *tmp;
1622
1623         temp_ima_appraise = 0;
1624         list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
1625                 list_del(&entry->list);
1626                 ima_free_rule(entry);
1627         }
1628 }
1629
1630 #define __ima_hook_stringify(func, str) (#func),
1631
1632 const char *const func_tokens[] = {
1633         __ima_hooks(__ima_hook_stringify)
1634 };
1635
1636 #ifdef  CONFIG_IMA_READ_POLICY
1637 enum {
1638         mask_exec = 0, mask_write, mask_read, mask_append
1639 };
1640
1641 static const char *const mask_tokens[] = {
1642         "^MAY_EXEC",
1643         "^MAY_WRITE",
1644         "^MAY_READ",
1645         "^MAY_APPEND"
1646 };
1647
1648 void *ima_policy_start(struct seq_file *m, loff_t *pos)
1649 {
1650         loff_t l = *pos;
1651         struct ima_rule_entry *entry;
1652
1653         rcu_read_lock();
1654         list_for_each_entry_rcu(entry, ima_rules, list) {
1655                 if (!l--) {
1656                         rcu_read_unlock();
1657                         return entry;
1658                 }
1659         }
1660         rcu_read_unlock();
1661         return NULL;
1662 }
1663
1664 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos)
1665 {
1666         struct ima_rule_entry *entry = v;
1667
1668         rcu_read_lock();
1669         entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list);
1670         rcu_read_unlock();
1671         (*pos)++;
1672
1673         return (&entry->list == ima_rules) ? NULL : entry;
1674 }
1675
1676 void ima_policy_stop(struct seq_file *m, void *v)
1677 {
1678 }
1679
1680 #define pt(token)       policy_tokens[token].pattern
1681 #define mt(token)       mask_tokens[token]
1682
1683 /*
1684  * policy_func_show - display the ima_hooks policy rule
1685  */
1686 static void policy_func_show(struct seq_file *m, enum ima_hooks func)
1687 {
1688         if (func > 0 && func < MAX_CHECK)
1689                 seq_printf(m, "func=%s ", func_tokens[func]);
1690         else
1691                 seq_printf(m, "func=%d ", func);
1692 }
1693
1694 static void ima_show_rule_opt_list(struct seq_file *m,
1695                                    const struct ima_rule_opt_list *opt_list)
1696 {
1697         size_t i;
1698
1699         for (i = 0; i < opt_list->count; i++)
1700                 seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
1701 }
1702
1703 int ima_policy_show(struct seq_file *m, void *v)
1704 {
1705         struct ima_rule_entry *entry = v;
1706         int i;
1707         char tbuf[64] = {0,};
1708         int offset = 0;
1709
1710         rcu_read_lock();
1711
1712         if (entry->action & MEASURE)
1713                 seq_puts(m, pt(Opt_measure));
1714         if (entry->action & DONT_MEASURE)
1715                 seq_puts(m, pt(Opt_dont_measure));
1716         if (entry->action & APPRAISE)
1717                 seq_puts(m, pt(Opt_appraise));
1718         if (entry->action & DONT_APPRAISE)
1719                 seq_puts(m, pt(Opt_dont_appraise));
1720         if (entry->action & AUDIT)
1721                 seq_puts(m, pt(Opt_audit));
1722         if (entry->action & HASH)
1723                 seq_puts(m, pt(Opt_hash));
1724         if (entry->action & DONT_HASH)
1725                 seq_puts(m, pt(Opt_dont_hash));
1726
1727         seq_puts(m, " ");
1728
1729         if (entry->flags & IMA_FUNC)
1730                 policy_func_show(m, entry->func);
1731
1732         if ((entry->flags & IMA_MASK) || (entry->flags & IMA_INMASK)) {
1733                 if (entry->flags & IMA_MASK)
1734                         offset = 1;
1735                 if (entry->mask & MAY_EXEC)
1736                         seq_printf(m, pt(Opt_mask), mt(mask_exec) + offset);
1737                 if (entry->mask & MAY_WRITE)
1738                         seq_printf(m, pt(Opt_mask), mt(mask_write) + offset);
1739                 if (entry->mask & MAY_READ)
1740                         seq_printf(m, pt(Opt_mask), mt(mask_read) + offset);
1741                 if (entry->mask & MAY_APPEND)
1742                         seq_printf(m, pt(Opt_mask), mt(mask_append) + offset);
1743                 seq_puts(m, " ");
1744         }
1745
1746         if (entry->flags & IMA_FSMAGIC) {
1747                 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic);
1748                 seq_printf(m, pt(Opt_fsmagic), tbuf);
1749                 seq_puts(m, " ");
1750         }
1751
1752         if (entry->flags & IMA_FSNAME) {
1753                 snprintf(tbuf, sizeof(tbuf), "%s", entry->fsname);
1754                 seq_printf(m, pt(Opt_fsname), tbuf);
1755                 seq_puts(m, " ");
1756         }
1757
1758         if (entry->flags & IMA_KEYRINGS) {
1759                 seq_puts(m, "keyrings=");
1760                 ima_show_rule_opt_list(m, entry->keyrings);
1761                 seq_puts(m, " ");
1762         }
1763
1764         if (entry->flags & IMA_LABEL) {
1765                 seq_puts(m, "label=");
1766                 ima_show_rule_opt_list(m, entry->label);
1767                 seq_puts(m, " ");
1768         }
1769
1770         if (entry->flags & IMA_PCR) {
1771                 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr);
1772                 seq_printf(m, pt(Opt_pcr), tbuf);
1773                 seq_puts(m, " ");
1774         }
1775
1776         if (entry->flags & IMA_FSUUID) {
1777                 seq_printf(m, "fsuuid=%pU", &entry->fsuuid);
1778                 seq_puts(m, " ");
1779         }
1780
1781         if (entry->flags & IMA_UID) {
1782                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1783                 if (entry->uid_op == &uid_gt)
1784                         seq_printf(m, pt(Opt_uid_gt), tbuf);
1785                 else if (entry->uid_op == &uid_lt)
1786                         seq_printf(m, pt(Opt_uid_lt), tbuf);
1787                 else
1788                         seq_printf(m, pt(Opt_uid_eq), tbuf);
1789                 seq_puts(m, " ");
1790         }
1791
1792         if (entry->flags & IMA_EUID) {
1793                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid));
1794                 if (entry->uid_op == &uid_gt)
1795                         seq_printf(m, pt(Opt_euid_gt), tbuf);
1796                 else if (entry->uid_op == &uid_lt)
1797                         seq_printf(m, pt(Opt_euid_lt), tbuf);
1798                 else
1799                         seq_printf(m, pt(Opt_euid_eq), tbuf);
1800                 seq_puts(m, " ");
1801         }
1802
1803         if (entry->flags & IMA_FOWNER) {
1804                 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner));
1805                 if (entry->fowner_op == &uid_gt)
1806                         seq_printf(m, pt(Opt_fowner_gt), tbuf);
1807                 else if (entry->fowner_op == &uid_lt)
1808                         seq_printf(m, pt(Opt_fowner_lt), tbuf);
1809                 else
1810                         seq_printf(m, pt(Opt_fowner_eq), tbuf);
1811                 seq_puts(m, " ");
1812         }
1813
1814         for (i = 0; i < MAX_LSM_RULES; i++) {
1815                 if (entry->lsm[i].rule) {
1816                         switch (i) {
1817                         case LSM_OBJ_USER:
1818                                 seq_printf(m, pt(Opt_obj_user),
1819                                            entry->lsm[i].args_p);
1820                                 break;
1821                         case LSM_OBJ_ROLE:
1822                                 seq_printf(m, pt(Opt_obj_role),
1823                                            entry->lsm[i].args_p);
1824                                 break;
1825                         case LSM_OBJ_TYPE:
1826                                 seq_printf(m, pt(Opt_obj_type),
1827                                            entry->lsm[i].args_p);
1828                                 break;
1829                         case LSM_SUBJ_USER:
1830                                 seq_printf(m, pt(Opt_subj_user),
1831                                            entry->lsm[i].args_p);
1832                                 break;
1833                         case LSM_SUBJ_ROLE:
1834                                 seq_printf(m, pt(Opt_subj_role),
1835                                            entry->lsm[i].args_p);
1836                                 break;
1837                         case LSM_SUBJ_TYPE:
1838                                 seq_printf(m, pt(Opt_subj_type),
1839                                            entry->lsm[i].args_p);
1840                                 break;
1841                         }
1842                         seq_puts(m, " ");
1843                 }
1844         }
1845         if (entry->template)
1846                 seq_printf(m, "template=%s ", entry->template->name);
1847         if (entry->flags & IMA_DIGSIG_REQUIRED) {
1848                 if (entry->flags & IMA_MODSIG_ALLOWED)
1849                         seq_puts(m, "appraise_type=imasig|modsig ");
1850                 else
1851                         seq_puts(m, "appraise_type=imasig ");
1852         }
1853         if (entry->flags & IMA_CHECK_BLACKLIST)
1854                 seq_puts(m, "appraise_flag=check_blacklist ");
1855         if (entry->flags & IMA_PERMIT_DIRECTIO)
1856                 seq_puts(m, "permit_directio ");
1857         rcu_read_unlock();
1858         seq_puts(m, "\n");
1859         return 0;
1860 }
1861 #endif  /* CONFIG_IMA_READ_POLICY */
1862
1863 #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
1864 /*
1865  * ima_appraise_signature: whether IMA will appraise a given function using
1866  * an IMA digital signature. This is restricted to cases where the kernel
1867  * has a set of built-in trusted keys in order to avoid an attacker simply
1868  * loading additional keys.
1869  */
1870 bool ima_appraise_signature(enum kernel_read_file_id id)
1871 {
1872         struct ima_rule_entry *entry;
1873         bool found = false;
1874         enum ima_hooks func;
1875
1876         if (id >= READING_MAX_ID)
1877                 return false;
1878
1879         func = read_idmap[id] ?: FILE_CHECK;
1880
1881         rcu_read_lock();
1882         list_for_each_entry_rcu(entry, ima_rules, list) {
1883                 if (entry->action != APPRAISE)
1884                         continue;
1885
1886                 /*
1887                  * A generic entry will match, but otherwise require that it
1888                  * match the func we're looking for
1889                  */
1890                 if (entry->func && entry->func != func)
1891                         continue;
1892
1893                 /*
1894                  * We require this to be a digital signature, not a raw IMA
1895                  * hash.
1896                  */
1897                 if (entry->flags & IMA_DIGSIG_REQUIRED)
1898                         found = true;
1899
1900                 /*
1901                  * We've found a rule that matches, so break now even if it
1902                  * didn't require a digital signature - a later rule that does
1903                  * won't override it, so would be a false positive.
1904                  */
1905                 break;
1906         }
1907
1908         rcu_read_unlock();
1909         return found;
1910 }
1911 #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */