1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) 2011 IBM Corporation 4 * 5 * Author: 6 * Mimi Zohar <zohar@us.ibm.com> 7 */ 8#include <linux/module.h> 9#include <linux/init.h> 10#include <linux/file.h> 11#include <linux/fs.h> 12#include <linux/xattr.h> 13#include <linux/magic.h> 14#include <linux/ima.h> 15#include <linux/evm.h> 16#include <linux/fsverity.h> 17#include <keys/system_keyring.h> 18#include <uapi/linux/fsverity.h> 19 20#include "ima.h" 21 22#ifdef CONFIG_IMA_APPRAISE_BOOTPARAM 23static char *ima_appraise_cmdline_default __initdata; 24core_param(ima_appraise, ima_appraise_cmdline_default, charp, 0); 25 26void __init ima_appraise_parse_cmdline(void) 27{ 28 const char *str = ima_appraise_cmdline_default; 29 bool sb_state = arch_ima_get_secureboot(); 30 int appraisal_state = ima_appraise; 31 32 if (!str) 33 return; 34 35 if (strncmp(str, "off", 3) == 0) 36 appraisal_state = 0; 37 else if (strncmp(str, "log", 3) == 0) 38 appraisal_state = IMA_APPRAISE_LOG; 39 else if (strncmp(str, "fix", 3) == 0) 40 appraisal_state = IMA_APPRAISE_FIX; 41 else if (strncmp(str, "enforce", 7) == 0) 42 appraisal_state = IMA_APPRAISE_ENFORCE; 43 else 44 pr_err("invalid \"%s\" appraise option", str); 45 46 /* If appraisal state was changed, but secure boot is enabled, 47 * keep its default */ 48 if (sb_state) { 49 if (!(appraisal_state & IMA_APPRAISE_ENFORCE)) 50 pr_info("Secure boot enabled: ignoring ima_appraise=%s option", 51 str); 52 } else { 53 ima_appraise = appraisal_state; 54 } 55} 56#endif 57 58/* 59 * is_ima_appraise_enabled - return appraise status 60 * 61 * Only return enabled, if not in ima_appraise="fix" or "log" modes. 62 */ 63bool is_ima_appraise_enabled(void) 64{ 65 return ima_appraise & IMA_APPRAISE_ENFORCE; 66} 67 68/* 69 * ima_must_appraise - set appraise flag 70 * 71 * Return 1 to appraise or hash 72 */ 73int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode, 74 int mask, enum ima_hooks func) 75{ 76 u32 secid; 77 78 if (!ima_appraise) 79 return 0; 80 81 security_current_getsecid_subj(&secid); 82 return ima_match_policy(idmap, inode, current_cred(), secid, 83 func, mask, IMA_APPRAISE | IMA_HASH, NULL, 84 NULL, NULL, NULL); 85} 86 87static int ima_fix_xattr(struct dentry *dentry, 88 struct integrity_iint_cache *iint) 89{ 90 int rc, offset; 91 u8 algo = iint->ima_hash->algo; 92 93 if (algo <= HASH_ALGO_SHA1) { 94 offset = 1; 95 iint->ima_hash->xattr.sha1.type = IMA_XATTR_DIGEST; 96 } else { 97 offset = 0; 98 iint->ima_hash->xattr.ng.type = IMA_XATTR_DIGEST_NG; 99 iint->ima_hash->xattr.ng.algo = algo; 100 } 101 rc = __vfs_setxattr_noperm(&nop_mnt_idmap, dentry, XATTR_NAME_IMA, 102 &iint->ima_hash->xattr.data[offset], 103 (sizeof(iint->ima_hash->xattr) - offset) + 104 iint->ima_hash->length, 0); 105 return rc; 106} 107 108/* Return specific func appraised cached result */ 109enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint, 110 enum ima_hooks func) 111{ 112 switch (func) { 113 case MMAP_CHECK: 114 case MMAP_CHECK_REQPROT: 115 return iint->ima_mmap_status; 116 case BPRM_CHECK: 117 return iint->ima_bprm_status; 118 case CREDS_CHECK: 119 return iint->ima_creds_status; 120 case FILE_CHECK: 121 case POST_SETATTR: 122 return iint->ima_file_status; 123 case MODULE_CHECK ... MAX_CHECK - 1: 124 default: 125 return iint->ima_read_status; 126 } 127} 128 129static void ima_set_cache_status(struct integrity_iint_cache *iint, 130 enum ima_hooks func, 131 enum integrity_status status) 132{ 133 switch (func) { 134 case MMAP_CHECK: 135 case MMAP_CHECK_REQPROT: 136 iint->ima_mmap_status = status; 137 break; 138 case BPRM_CHECK: 139 iint->ima_bprm_status = status; 140 break; 141 case CREDS_CHECK: 142 iint->ima_creds_status = status; 143 break; 144 case FILE_CHECK: 145 case POST_SETATTR: 146 iint->ima_file_status = status; 147 break; 148 case MODULE_CHECK ... MAX_CHECK - 1: 149 default: 150 iint->ima_read_status = status; 151 break; 152 } 153} 154 155static void ima_cache_flags(struct integrity_iint_cache *iint, 156 enum ima_hooks func) 157{ 158 switch (func) { 159 case MMAP_CHECK: 160 case MMAP_CHECK_REQPROT: 161 iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED); 162 break; 163 case BPRM_CHECK: 164 iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED); 165 break; 166 case CREDS_CHECK: 167 iint->flags |= (IMA_CREDS_APPRAISED | IMA_APPRAISED); 168 break; 169 case FILE_CHECK: 170 case POST_SETATTR: 171 iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED); 172 break; 173 case MODULE_CHECK ... MAX_CHECK - 1: 174 default: 175 iint->flags |= (IMA_READ_APPRAISED | IMA_APPRAISED); 176 break; 177 } 178} 179 180enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value, 181 int xattr_len) 182{ 183 struct signature_v2_hdr *sig; 184 enum hash_algo ret; 185 186 if (!xattr_value || xattr_len < 2) 187 /* return default hash algo */ 188 return ima_hash_algo; 189 190 switch (xattr_value->type) { 191 case IMA_VERITY_DIGSIG: 192 sig = (typeof(sig))xattr_value; 193 if (sig->version != 3 || xattr_len <= sizeof(*sig) || 194 sig->hash_algo >= HASH_ALGO__LAST) 195 return ima_hash_algo; 196 return sig->hash_algo; 197 case EVM_IMA_XATTR_DIGSIG: 198 sig = (typeof(sig))xattr_value; 199 if (sig->version != 2 || xattr_len <= sizeof(*sig) 200 || sig->hash_algo >= HASH_ALGO__LAST) 201 return ima_hash_algo; 202 return sig->hash_algo; 203 case IMA_XATTR_DIGEST_NG: 204 /* first byte contains algorithm id */ 205 ret = xattr_value->data[0]; 206 if (ret < HASH_ALGO__LAST) 207 return ret; 208 break; 209 case IMA_XATTR_DIGEST: 210 /* this is for backward compatibility */ 211 if (xattr_len == 21) { 212 unsigned int zero = 0; 213 if (!memcmp(&xattr_value->data[16], &zero, 4)) 214 return HASH_ALGO_MD5; 215 else 216 return HASH_ALGO_SHA1; 217 } else if (xattr_len == 17) 218 return HASH_ALGO_MD5; 219 break; 220 } 221 222 /* return default hash algo */ 223 return ima_hash_algo; 224} 225 226int ima_read_xattr(struct dentry *dentry, 227 struct evm_ima_xattr_data **xattr_value, int xattr_len) 228{ 229 int ret; 230 231 ret = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_IMA, 232 (char **)xattr_value, xattr_len, GFP_NOFS); 233 if (ret == -EOPNOTSUPP) 234 ret = 0; 235 return ret; 236} 237 238/* 239 * calc_file_id_hash - calculate the hash of the ima_file_id struct data 240 * @type: xattr type [enum evm_ima_xattr_type] 241 * @algo: hash algorithm [enum hash_algo] 242 * @digest: pointer to the digest to be hashed 243 * @hash: (out) pointer to the hash 244 * 245 * IMA signature version 3 disambiguates the data that is signed by 246 * indirectly signing the hash of the ima_file_id structure data. 247 * 248 * Signing the ima_file_id struct is currently only supported for 249 * IMA_VERITY_DIGSIG type xattrs. 250 * 251 * Return 0 on success, error code otherwise. 252 */ 253static int calc_file_id_hash(enum evm_ima_xattr_type type, 254 enum hash_algo algo, const u8 *digest, 255 struct ima_digest_data *hash) 256{ 257 struct ima_file_id file_id = { 258 .hash_type = IMA_VERITY_DIGSIG, .hash_algorithm = algo}; 259 unsigned int unused = HASH_MAX_DIGESTSIZE - hash_digest_size[algo]; 260 261 if (type != IMA_VERITY_DIGSIG) 262 return -EINVAL; 263 264 memcpy(file_id.hash, digest, hash_digest_size[algo]); 265 266 hash->algo = algo; 267 hash->length = hash_digest_size[algo]; 268 269 return ima_calc_buffer_hash(&file_id, sizeof(file_id) - unused, hash); 270} 271 272/* 273 * xattr_verify - verify xattr digest or signature 274 * 275 * Verify whether the hash or signature matches the file contents. 276 * 277 * Return 0 on success, error code otherwise. 278 */ 279static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, 280 struct evm_ima_xattr_data *xattr_value, int xattr_len, 281 enum integrity_status *status, const char **cause) 282{ 283 struct ima_max_digest_data hash; 284 struct signature_v2_hdr *sig; 285 int rc = -EINVAL, hash_start = 0; 286 int mask; 287 288 switch (xattr_value->type) { 289 case IMA_XATTR_DIGEST_NG: 290 /* first byte contains algorithm id */ 291 hash_start = 1; 292 fallthrough; 293 case IMA_XATTR_DIGEST: 294 if (*status != INTEGRITY_PASS_IMMUTABLE) { 295 if (iint->flags & IMA_DIGSIG_REQUIRED) { 296 if (iint->flags & IMA_VERITY_REQUIRED) 297 *cause = "verity-signature-required"; 298 else 299 *cause = "IMA-signature-required"; 300 *status = INTEGRITY_FAIL; 301 break; 302 } 303 clear_bit(IMA_DIGSIG, &iint->atomic_flags); 304 } else { 305 set_bit(IMA_DIGSIG, &iint->atomic_flags); 306 } 307 if (xattr_len - sizeof(xattr_value->type) - hash_start >= 308 iint->ima_hash->length) 309 /* 310 * xattr length may be longer. md5 hash in previous 311 * version occupied 20 bytes in xattr, instead of 16 312 */ 313 rc = memcmp(&xattr_value->data[hash_start], 314 iint->ima_hash->digest, 315 iint->ima_hash->length); 316 else 317 rc = -EINVAL; 318 if (rc) { 319 *cause = "invalid-hash"; 320 *status = INTEGRITY_FAIL; 321 break; 322 } 323 *status = INTEGRITY_PASS; 324 break; 325 case EVM_IMA_XATTR_DIGSIG: 326 set_bit(IMA_DIGSIG, &iint->atomic_flags); 327 328 mask = IMA_DIGSIG_REQUIRED | IMA_VERITY_REQUIRED; 329 if ((iint->flags & mask) == mask) { 330 *cause = "verity-signature-required"; 331 *status = INTEGRITY_FAIL; 332 break; 333 } 334 335 sig = (typeof(sig))xattr_value; 336 if (sig->version >= 3) { 337 *cause = "invalid-signature-version"; 338 *status = INTEGRITY_FAIL; 339 break; 340 } 341 rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, 342 (const char *)xattr_value, 343 xattr_len, 344 iint->ima_hash->digest, 345 iint->ima_hash->length); 346 if (rc == -EOPNOTSUPP) { 347 *status = INTEGRITY_UNKNOWN; 348 break; 349 } 350 if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc && 351 func == KEXEC_KERNEL_CHECK) 352 rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM, 353 (const char *)xattr_value, 354 xattr_len, 355 iint->ima_hash->digest, 356 iint->ima_hash->length); 357 if (rc) { 358 *cause = "invalid-signature"; 359 *status = INTEGRITY_FAIL; 360 } else { 361 *status = INTEGRITY_PASS; 362 } 363 break; 364 case IMA_VERITY_DIGSIG: 365 set_bit(IMA_DIGSIG, &iint->atomic_flags); 366 367 if (iint->flags & IMA_DIGSIG_REQUIRED) { 368 if (!(iint->flags & IMA_VERITY_REQUIRED)) { 369 *cause = "IMA-signature-required"; 370 *status = INTEGRITY_FAIL; 371 break; 372 } 373 } 374 375 sig = (typeof(sig))xattr_value; 376 if (sig->version != 3) { 377 *cause = "invalid-signature-version"; 378 *status = INTEGRITY_FAIL; 379 break; 380 } 381 382 rc = calc_file_id_hash(IMA_VERITY_DIGSIG, iint->ima_hash->algo, 383 iint->ima_hash->digest, &hash.hdr); 384 if (rc) { 385 *cause = "sigv3-hashing-error"; 386 *status = INTEGRITY_FAIL; 387 break; 388 } 389 390 rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, 391 (const char *)xattr_value, 392 xattr_len, hash.digest, 393 hash.hdr.length); 394 if (rc) { 395 *cause = "invalid-verity-signature"; 396 *status = INTEGRITY_FAIL; 397 } else { 398 *status = INTEGRITY_PASS; 399 } 400 401 break; 402 default: 403 *status = INTEGRITY_UNKNOWN; 404 *cause = "unknown-ima-data"; 405 break; 406 } 407 408 return rc; 409} 410 411/* 412 * modsig_verify - verify modsig signature 413 * 414 * Verify whether the signature matches the file contents. 415 * 416 * Return 0 on success, error code otherwise. 417 */ 418static int modsig_verify(enum ima_hooks func, const struct modsig *modsig, 419 enum integrity_status *status, const char **cause) 420{ 421 int rc; 422 423 rc = integrity_modsig_verify(INTEGRITY_KEYRING_IMA, modsig); 424 if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc && 425 func == KEXEC_KERNEL_CHECK) 426 rc = integrity_modsig_verify(INTEGRITY_KEYRING_PLATFORM, 427 modsig); 428 if (rc) { 429 *cause = "invalid-signature"; 430 *status = INTEGRITY_FAIL; 431 } else { 432 *status = INTEGRITY_PASS; 433 } 434 435 return rc; 436} 437 438/* 439 * ima_check_blacklist - determine if the binary is blacklisted. 440 * 441 * Add the hash of the blacklisted binary to the measurement list, based 442 * on policy. 443 * 444 * Returns -EPERM if the hash is blacklisted. 445 */ 446int ima_check_blacklist(struct integrity_iint_cache *iint, 447 const struct modsig *modsig, int pcr) 448{ 449 enum hash_algo hash_algo; 450 const u8 *digest = NULL; 451 u32 digestsize = 0; 452 int rc = 0; 453 454 if (!(iint->flags & IMA_CHECK_BLACKLIST)) 455 return 0; 456 457 if (iint->flags & IMA_MODSIG_ALLOWED && modsig) { 458 ima_get_modsig_digest(modsig, &hash_algo, &digest, &digestsize); 459 460 rc = is_binary_blacklisted(digest, digestsize); 461 } else if (iint->flags & IMA_DIGSIG_REQUIRED && iint->ima_hash) 462 rc = is_binary_blacklisted(iint->ima_hash->digest, iint->ima_hash->length); 463 464 if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) 465 process_buffer_measurement(&nop_mnt_idmap, NULL, digest, digestsize, 466 "blacklisted-hash", NONE, 467 pcr, NULL, false, NULL, 0); 468 469 return rc; 470} 471 472/* 473 * ima_appraise_measurement - appraise file measurement 474 * 475 * Call evm_verifyxattr() to verify the integrity of 'security.ima'. 476 * Assuming success, compare the xattr hash with the collected measurement. 477 * 478 * Return 0 on success, error code otherwise 479 */ 480int ima_appraise_measurement(enum ima_hooks func, 481 struct integrity_iint_cache *iint, 482 struct file *file, const unsigned char *filename, 483 struct evm_ima_xattr_data *xattr_value, 484 int xattr_len, const struct modsig *modsig) 485{ 486 static const char op[] = "appraise_data"; 487 const char *cause = "unknown"; 488 struct dentry *dentry = file_dentry(file); 489 struct inode *inode = d_backing_inode(dentry); 490 enum integrity_status status = INTEGRITY_UNKNOWN; 491 int rc = xattr_len; 492 bool try_modsig = iint->flags & IMA_MODSIG_ALLOWED && modsig; 493 494 /* If not appraising a modsig, we need an xattr. */ 495 if (!(inode->i_opflags & IOP_XATTR) && !try_modsig) 496 return INTEGRITY_UNKNOWN; 497 498 /* If reading the xattr failed and there's no modsig, error out. */ 499 if (rc <= 0 && !try_modsig) { 500 if (rc && rc != -ENODATA) 501 goto out; 502 503 if (iint->flags & IMA_DIGSIG_REQUIRED) { 504 if (iint->flags & IMA_VERITY_REQUIRED) 505 cause = "verity-signature-required"; 506 else 507 cause = "IMA-signature-required"; 508 } else { 509 cause = "missing-hash"; 510 } 511 512 status = INTEGRITY_NOLABEL; 513 if (file->f_mode & FMODE_CREATED) 514 iint->flags |= IMA_NEW_FILE; 515 if ((iint->flags & IMA_NEW_FILE) && 516 (!(iint->flags & IMA_DIGSIG_REQUIRED) || 517 (inode->i_size == 0))) 518 status = INTEGRITY_PASS; 519 goto out; 520 } 521 522 status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, 523 rc < 0 ? 0 : rc, iint); 524 switch (status) { 525 case INTEGRITY_PASS: 526 case INTEGRITY_PASS_IMMUTABLE: 527 case INTEGRITY_UNKNOWN: 528 break; 529 case INTEGRITY_NOXATTRS: /* No EVM protected xattrs. */ 530 /* It's fine not to have xattrs when using a modsig. */ 531 if (try_modsig) 532 break; 533 fallthrough; 534 case INTEGRITY_NOLABEL: /* No security.evm xattr. */ 535 cause = "missing-HMAC"; 536 goto out; 537 case INTEGRITY_FAIL_IMMUTABLE: 538 set_bit(IMA_DIGSIG, &iint->atomic_flags); 539 cause = "invalid-fail-immutable"; 540 goto out; 541 case INTEGRITY_FAIL: /* Invalid HMAC/signature. */ 542 cause = "invalid-HMAC"; 543 goto out; 544 default: 545 WARN_ONCE(true, "Unexpected integrity status %d\n", status); 546 } 547 548 if (xattr_value) 549 rc = xattr_verify(func, iint, xattr_value, xattr_len, &status, 550 &cause); 551 552 /* 553 * If we have a modsig and either no imasig or the imasig's key isn't 554 * known, then try verifying the modsig. 555 */ 556 if (try_modsig && 557 (!xattr_value || xattr_value->type == IMA_XATTR_DIGEST_NG || 558 rc == -ENOKEY)) 559 rc = modsig_verify(func, modsig, &status, &cause); 560 561out: 562 /* 563 * File signatures on some filesystems can not be properly verified. 564 * When such filesystems are mounted by an untrusted mounter or on a 565 * system not willing to accept such a risk, fail the file signature 566 * verification. 567 */ 568 if ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) && 569 ((inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) || 570 (iint->flags & IMA_FAIL_UNVERIFIABLE_SIGS))) { 571 status = INTEGRITY_FAIL; 572 cause = "unverifiable-signature"; 573 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, 574 op, cause, rc, 0); 575 } else if (status != INTEGRITY_PASS) { 576 /* Fix mode, but don't replace file signatures. */ 577 if ((ima_appraise & IMA_APPRAISE_FIX) && !try_modsig && 578 (!xattr_value || 579 xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { 580 if (!ima_fix_xattr(dentry, iint)) 581 status = INTEGRITY_PASS; 582 } 583 584 /* 585 * Permit new files with file/EVM portable signatures, but 586 * without data. 587 */ 588 if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE && 589 test_bit(IMA_DIGSIG, &iint->atomic_flags)) { 590 status = INTEGRITY_PASS; 591 } 592 593 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, 594 op, cause, rc, 0); 595 } else { 596 ima_cache_flags(iint, func); 597 } 598 599 ima_set_cache_status(iint, func, status); 600 return status; 601} 602 603/* 604 * ima_update_xattr - update 'security.ima' hash value 605 */ 606void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file) 607{ 608 struct dentry *dentry = file_dentry(file); 609 int rc = 0; 610 611 /* do not collect and update hash for digital signatures */ 612 if (test_bit(IMA_DIGSIG, &iint->atomic_flags)) 613 return; 614 615 if ((iint->ima_file_status != INTEGRITY_PASS) && 616 !(iint->flags & IMA_HASH)) 617 return; 618 619 rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo, NULL); 620 if (rc < 0) 621 return; 622 623 inode_lock(file_inode(file)); 624 ima_fix_xattr(dentry, iint); 625 inode_unlock(file_inode(file)); 626} 627 628/** 629 * ima_inode_post_setattr - reflect file metadata changes 630 * @idmap: idmap of the mount the inode was found from 631 * @dentry: pointer to the affected dentry 632 * 633 * Changes to a dentry's metadata might result in needing to appraise. 634 * 635 * This function is called from notify_change(), which expects the caller 636 * to lock the inode's i_mutex. 637 */ 638void ima_inode_post_setattr(struct mnt_idmap *idmap, 639 struct dentry *dentry) 640{ 641 struct inode *inode = d_backing_inode(dentry); 642 struct integrity_iint_cache *iint; 643 int action; 644 645 if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode) 646 || !(inode->i_opflags & IOP_XATTR)) 647 return; 648 649 action = ima_must_appraise(idmap, inode, MAY_ACCESS, POST_SETATTR); 650 iint = integrity_iint_find(inode); 651 if (iint) { 652 set_bit(IMA_CHANGE_ATTR, &iint->atomic_flags); 653 if (!action) 654 clear_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); 655 } 656} 657 658/* 659 * ima_protect_xattr - protect 'security.ima' 660 * 661 * Ensure that not just anyone can modify or remove 'security.ima'. 662 */ 663static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name, 664 const void *xattr_value, size_t xattr_value_len) 665{ 666 if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) { 667 if (!capable(CAP_SYS_ADMIN)) 668 return -EPERM; 669 return 1; 670 } 671 return 0; 672} 673 674static void ima_reset_appraise_flags(struct inode *inode, int digsig) 675{ 676 struct integrity_iint_cache *iint; 677 678 if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)) 679 return; 680 681 iint = integrity_iint_find(inode); 682 if (!iint) 683 return; 684 iint->measured_pcrs = 0; 685 set_bit(IMA_CHANGE_XATTR, &iint->atomic_flags); 686 if (digsig) 687 set_bit(IMA_DIGSIG, &iint->atomic_flags); 688 else 689 clear_bit(IMA_DIGSIG, &iint->atomic_flags); 690} 691 692/** 693 * validate_hash_algo() - Block setxattr with unsupported hash algorithms 694 * @dentry: object of the setxattr() 695 * @xattr_value: userland supplied xattr value 696 * @xattr_value_len: length of xattr_value 697 * 698 * The xattr value is mapped to its hash algorithm, and this algorithm 699 * must be built in the kernel for the setxattr to be allowed. 700 * 701 * Emit an audit message when the algorithm is invalid. 702 * 703 * Return: 0 on success, else an error. 704 */ 705static int validate_hash_algo(struct dentry *dentry, 706 const struct evm_ima_xattr_data *xattr_value, 707 size_t xattr_value_len) 708{ 709 char *path = NULL, *pathbuf = NULL; 710 enum hash_algo xattr_hash_algo; 711 const char *errmsg = "unavailable-hash-algorithm"; 712 unsigned int allowed_hashes; 713 714 xattr_hash_algo = ima_get_hash_algo(xattr_value, xattr_value_len); 715 716 allowed_hashes = atomic_read(&ima_setxattr_allowed_hash_algorithms); 717 718 if (allowed_hashes) { 719 /* success if the algorithm is allowed in the ima policy */ 720 if (allowed_hashes & (1U << xattr_hash_algo)) 721 return 0; 722 723 /* 724 * We use a different audit message when the hash algorithm 725 * is denied by a policy rule, instead of not being built 726 * in the kernel image 727 */ 728 errmsg = "denied-hash-algorithm"; 729 } else { 730 if (likely(xattr_hash_algo == ima_hash_algo)) 731 return 0; 732 733 /* allow any xattr using an algorithm built in the kernel */ 734 if (crypto_has_alg(hash_algo_name[xattr_hash_algo], 0, 0)) 735 return 0; 736 } 737 738 pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); 739 if (!pathbuf) 740 return -EACCES; 741 742 path = dentry_path(dentry, pathbuf, PATH_MAX); 743 744 integrity_audit_msg(AUDIT_INTEGRITY_DATA, d_inode(dentry), path, 745 "set_data", errmsg, -EACCES, 0); 746 747 kfree(pathbuf); 748 749 return -EACCES; 750} 751 752int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, 753 const void *xattr_value, size_t xattr_value_len) 754{ 755 const struct evm_ima_xattr_data *xvalue = xattr_value; 756 int digsig = 0; 757 int result; 758 int err; 759 760 result = ima_protect_xattr(dentry, xattr_name, xattr_value, 761 xattr_value_len); 762 if (result == 1) { 763 if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST)) 764 return -EINVAL; 765 766 err = validate_hash_algo(dentry, xvalue, xattr_value_len); 767 if (err) 768 return err; 769 770 digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG); 771 } else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) { 772 digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG); 773 } 774 if (result == 1 || evm_revalidate_status(xattr_name)) { 775 ima_reset_appraise_flags(d_backing_inode(dentry), digsig); 776 if (result == 1) 777 result = 0; 778 } 779 return result; 780} 781 782int ima_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 783 const char *acl_name, struct posix_acl *kacl) 784{ 785 if (evm_revalidate_status(acl_name)) 786 ima_reset_appraise_flags(d_backing_inode(dentry), 0); 787 788 return 0; 789} 790 791int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) 792{ 793 int result; 794 795 result = ima_protect_xattr(dentry, xattr_name, NULL, 0); 796 if (result == 1 || evm_revalidate_status(xattr_name)) { 797 ima_reset_appraise_flags(d_backing_inode(dentry), 0); 798 if (result == 1) 799 result = 0; 800 } 801 return result; 802} 803