1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Integrity Measurement Architecture 4 * 5 * Copyright (C) 2005,2006,2007,2008 IBM Corporation 6 * 7 * Authors: 8 * Reiner Sailer <sailer@watson.ibm.com> 9 * Serge Hallyn <serue@us.ibm.com> 10 * Kylene Hall <kylene@us.ibm.com> 11 * Mimi Zohar <zohar@us.ibm.com> 12 * 13 * File: ima_main.c 14 * implements the IMA hooks: ima_bprm_check, ima_file_mmap, 15 * and ima_file_check. 16 */ 17 18 #include <linux/module.h> 19 #include <linux/file.h> 20 #include <linux/binfmts.h> 21 #include <linux/kernel_read_file.h> 22 #include <linux/mount.h> 23 #include <linux/mman.h> 24 #include <linux/slab.h> 25 #include <linux/xattr.h> 26 #include <linux/ima.h> 27 #include <linux/fs.h> 28 #include <linux/iversion.h> 29 #include <linux/evm.h> 30 #include <linux/crash_dump.h> 31 32 #include "ima.h" 33 34 #ifdef CONFIG_IMA_APPRAISE 35 int ima_appraise = IMA_APPRAISE_ENFORCE; 36 #else 37 int ima_appraise; 38 #endif 39 40 int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1; 41 static int hash_setup_done; 42 static int ima_disabled __ro_after_init; 43 44 static struct notifier_block ima_lsm_policy_notifier = { 45 .notifier_call = ima_lsm_policy_change, 46 }; 47 48 static int __init ima_setup(char *str) 49 { 50 if (!is_kdump_kernel()) { 51 pr_info("Warning: ima setup option only permitted in kdump"); 52 return 1; 53 } 54 55 if (strncmp(str, "off", 3) == 0) 56 ima_disabled = 1; 57 else if (strncmp(str, "on", 2) == 0) 58 ima_disabled = 0; 59 else 60 pr_err("Invalid ima setup option: \"%s\" , please specify ima=on|off.", str); 61 62 return 1; 63 } 64 __setup("ima=", ima_setup); 65 66 static int __init hash_setup(char *str) 67 { 68 struct ima_template_desc *template_desc = ima_template_desc_current(); 69 int i; 70 71 if (hash_setup_done) 72 return 1; 73 74 if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) { 75 if (strncmp(str, "sha1", 4) == 0) { 76 ima_hash_algo = HASH_ALGO_SHA1; 77 } else if (strncmp(str, "md5", 3) == 0) { 78 ima_hash_algo = HASH_ALGO_MD5; 79 } else { 80 pr_err("invalid hash algorithm \"%s\" for template \"%s\"", 81 str, IMA_TEMPLATE_IMA_NAME); 82 return 1; 83 } 84 goto out; 85 } 86 87 i = match_string(hash_algo_name, HASH_ALGO__LAST, str); 88 if (i < 0) { 89 pr_err("invalid hash algorithm \"%s\"", str); 90 return 1; 91 } 92 93 ima_hash_algo = i; 94 out: 95 hash_setup_done = 1; 96 return 1; 97 } 98 __setup("ima_hash=", hash_setup); 99 100 enum hash_algo ima_get_current_hash_algo(void) 101 { 102 return ima_hash_algo; 103 } 104 105 /* Prevent mmap'ing a file execute that is already mmap'ed write */ 106 static int mmap_violation_check(enum ima_hooks func, struct file *file, 107 char **pathbuf, const char **pathname, 108 char *filename) 109 { 110 struct inode *inode; 111 int rc = 0; 112 113 if ((func == MMAP_CHECK || func == MMAP_CHECK_REQPROT) && 114 mapping_writably_mapped(file->f_mapping)) { 115 rc = -ETXTBSY; 116 inode = file_inode(file); 117 118 if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */ 119 *pathname = ima_d_path(&file->f_path, pathbuf, 120 filename); 121 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname, 122 "mmap_file", "mmapped_writers", rc, 0, rc); 123 } 124 return rc; 125 } 126 127 /* 128 * ima_rdwr_violation_check 129 * 130 * Only invalidate the PCR for measured files: 131 * - Opening a file for write when already open for read, 132 * results in a time of measure, time of use (ToMToU) error. 133 * - Opening a file for read when already open for write, 134 * could result in a file measurement error. 135 * 136 */ 137 static void ima_rdwr_violation_check(struct file *file, 138 struct ima_iint_cache *iint, 139 int must_measure, 140 char **pathbuf, 141 const char **pathname, 142 char *filename) 143 { 144 struct inode *inode = file_inode(file); 145 fmode_t mode = file->f_mode; 146 bool send_tomtou = false, send_writers = false; 147 148 if (mode & FMODE_WRITE) { 149 if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) { 150 if (!iint) 151 iint = ima_iint_find(inode); 152 153 /* IMA_MEASURE is set from reader side */ 154 if (iint && test_and_clear_bit(IMA_MAY_EMIT_TOMTOU, 155 &iint->atomic_flags)) 156 send_tomtou = true; 157 } 158 } else { 159 if (must_measure) 160 set_bit(IMA_MAY_EMIT_TOMTOU, &iint->atomic_flags); 161 162 /* Limit number of open_writers violations */ 163 if (inode_is_open_for_write(inode) && must_measure) { 164 if (!test_and_set_bit(IMA_EMITTED_OPENWRITERS, 165 &iint->atomic_flags)) 166 send_writers = true; 167 } 168 } 169 170 if (!send_tomtou && !send_writers) 171 return; 172 173 *pathname = ima_d_path(&file->f_path, pathbuf, filename); 174 175 if (send_tomtou) 176 ima_add_violation(file, *pathname, iint, 177 "invalid_pcr", "ToMToU"); 178 if (send_writers) 179 ima_add_violation(file, *pathname, iint, 180 "invalid_pcr", "open_writers"); 181 } 182 183 /* 184 * Detect file change based on STATX_CHANGE_COOKIE, when supported, and 185 * fallback to detecting file change based on i_version. On filesystems 186 * which do not support either, assume the file changed. 187 */ 188 static bool ima_detect_file_change(struct ima_iint_cache *iint, 189 struct inode *inode, struct file *file) 190 { 191 struct kstat stat; 192 int result; 193 194 result = vfs_getattr_nosec(&file->f_path, &stat, STATX_CHANGE_COOKIE, 195 AT_STATX_SYNC_AS_STAT); 196 197 if (!result && stat.result_mask & STATX_CHANGE_COOKIE) 198 return stat.change_cookie != iint->real_inode.version; 199 200 if (IS_I_VERSION(inode)) 201 return !inode_eq_iversion(inode, iint->real_inode.version); 202 203 return true; 204 } 205 206 static void ima_check_last_writer(struct ima_iint_cache *iint, 207 struct inode *inode, struct file *file) 208 { 209 fmode_t mode = file->f_mode; 210 bool update; 211 212 if (!(mode & FMODE_WRITE)) 213 return; 214 215 mutex_lock(&iint->mutex); 216 if (atomic_read(&inode->i_writecount) == 1) { 217 clear_bit(IMA_EMITTED_OPENWRITERS, &iint->atomic_flags); 218 219 update = test_and_clear_bit(IMA_UPDATE_XATTR, 220 &iint->atomic_flags); 221 222 if (iint->flags & IMA_NEW_FILE || 223 ima_detect_file_change(iint, inode, file)) { 224 iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE); 225 iint->measured_pcrs = 0; 226 if (update) 227 ima_update_xattr(iint, file); 228 } 229 } 230 mutex_unlock(&iint->mutex); 231 } 232 233 /** 234 * ima_file_free - called on __fput() 235 * @file: pointer to file structure being freed 236 * 237 * Flag files that changed, based on i_version 238 */ 239 static void ima_file_free(struct file *file) 240 { 241 struct inode *inode = file_inode(file); 242 struct ima_iint_cache *iint; 243 244 if (!ima_policy_flag || !S_ISREG(inode->i_mode)) 245 return; 246 247 iint = ima_iint_find(inode); 248 if (!iint) 249 return; 250 251 ima_check_last_writer(iint, inode, file); 252 } 253 254 static int process_measurement(struct file *file, const struct cred *cred, 255 struct lsm_prop *prop, char *buf, loff_t size, 256 int mask, enum ima_hooks func, 257 enum kernel_read_file_id read_id, 258 bool bprm_is_check) 259 { 260 struct inode *real_inode, *inode = file_inode(file); 261 struct ima_iint_cache *iint = NULL; 262 struct ima_template_desc *template_desc = NULL; 263 struct inode *metadata_inode; 264 char *pathbuf = NULL; 265 char filename[NAME_MAX]; 266 const char *pathname = NULL; 267 int rc = 0, action, must_appraise = 0; 268 int pcr = CONFIG_IMA_MEASURE_PCR_IDX; 269 struct evm_ima_xattr_data *xattr_value = NULL; 270 struct modsig *modsig = NULL; 271 int xattr_len = 0; 272 bool violation_check; 273 enum hash_algo hash_algo; 274 unsigned int allowed_algos = 0; 275 276 if (!ima_policy_flag || !S_ISREG(inode->i_mode)) 277 return 0; 278 279 /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action 280 * bitmask based on the appraise/audit/measurement policy. 281 * Included is the appraise submask. 282 */ 283 action = ima_get_action(file_mnt_idmap(file), inode, cred, prop, 284 mask, func, &pcr, &template_desc, NULL, 285 &allowed_algos); 286 violation_check = ((func == FILE_CHECK || func == MMAP_CHECK || 287 func == MMAP_CHECK_REQPROT) && 288 (ima_policy_flag & IMA_MEASURE) && 289 ((action & IMA_MEASURE) || 290 (file->f_mode & FMODE_WRITE))); 291 if (!action && !violation_check) 292 return 0; 293 294 must_appraise = action & IMA_APPRAISE; 295 296 /* Is the appraise rule hook specific? */ 297 if (action & IMA_FILE_APPRAISE) 298 func = FILE_CHECK; 299 300 inode_lock(inode); 301 302 if (action) { 303 iint = ima_inode_get(inode); 304 if (!iint) 305 rc = -ENOMEM; 306 } 307 308 if (!rc && violation_check) 309 ima_rdwr_violation_check(file, iint, action & IMA_MEASURE, 310 &pathbuf, &pathname, filename); 311 312 inode_unlock(inode); 313 314 if (rc) 315 goto out; 316 if (!action) 317 goto out; 318 319 mutex_lock(&iint->mutex); 320 321 if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags)) 322 /* 323 * Reset appraisal flags (action and non-action rule-specific) 324 * if ima_inode_post_setattr was called. 325 */ 326 iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED | 327 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | 328 IMA_NONACTION_RULE_FLAGS); 329 330 /* 331 * Re-evaulate the file if either the xattr has changed or the 332 * kernel has no way of detecting file change on the filesystem. 333 * (Limited to privileged mounted filesystems.) 334 */ 335 if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) || 336 ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) && 337 !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) && 338 !(action & IMA_FAIL_UNVERIFIABLE_SIGS))) { 339 iint->flags &= ~IMA_DONE_MASK; 340 iint->measured_pcrs = 0; 341 } 342 343 /* 344 * On stacked filesystems, detect and re-evaluate file data and 345 * metadata changes. 346 */ 347 real_inode = d_real_inode(file_dentry(file)); 348 if (real_inode != inode && 349 (action & IMA_DO_MASK) && (iint->flags & IMA_DONE_MASK)) { 350 if (!IS_I_VERSION(real_inode) || 351 integrity_inode_attrs_changed(&iint->real_inode, 352 real_inode)) { 353 iint->flags &= ~IMA_DONE_MASK; 354 iint->measured_pcrs = 0; 355 } 356 357 /* 358 * Reset the EVM status when metadata changed. 359 */ 360 metadata_inode = d_inode(d_real(file_dentry(file), 361 D_REAL_METADATA)); 362 if (evm_metadata_changed(inode, metadata_inode)) 363 iint->flags &= ~(IMA_APPRAISED | 364 IMA_APPRAISED_SUBMASK); 365 } 366 367 /* Determine if already appraised/measured based on bitmask 368 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, 369 * IMA_AUDIT, IMA_AUDITED) 370 */ 371 iint->flags |= action; 372 action &= IMA_DO_MASK; 373 action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1); 374 375 /* If target pcr is already measured, unset IMA_MEASURE action */ 376 if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr))) 377 action ^= IMA_MEASURE; 378 379 /* HASH sets the digital signature and update flags, nothing else */ 380 if ((action & IMA_HASH) && 381 !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) { 382 xattr_len = ima_read_xattr(file_dentry(file), 383 &xattr_value, xattr_len); 384 if ((xattr_value && xattr_len > 2) && 385 (xattr_value->type == EVM_IMA_XATTR_DIGSIG)) 386 set_bit(IMA_DIGSIG, &iint->atomic_flags); 387 iint->flags |= IMA_HASHED; 388 action ^= IMA_HASH; 389 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); 390 } 391 392 /* Nothing to do, just return existing appraised status */ 393 if (!action) { 394 if (must_appraise) { 395 rc = mmap_violation_check(func, file, &pathbuf, 396 &pathname, filename); 397 if (!rc) 398 rc = ima_get_cache_status(iint, func); 399 } 400 goto out_locked; 401 } 402 403 if ((action & IMA_APPRAISE_SUBMASK) || 404 strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) { 405 /* read 'security.ima' */ 406 xattr_len = ima_read_xattr(file_dentry(file), 407 &xattr_value, xattr_len); 408 409 /* 410 * Read the appended modsig if allowed by the policy, and allow 411 * an additional measurement list entry, if needed, based on the 412 * template format and whether the file was already measured. 413 */ 414 if (iint->flags & IMA_MODSIG_ALLOWED) { 415 rc = ima_read_modsig(func, buf, size, &modsig); 416 417 if (!rc && ima_template_has_modsig(template_desc) && 418 iint->flags & IMA_MEASURED) 419 action |= IMA_MEASURE; 420 } 421 } 422 423 hash_algo = ima_get_hash_algo(xattr_value, xattr_len); 424 425 rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig); 426 if (rc != 0 && rc != -EBADF && rc != -EINVAL) 427 goto out_locked; 428 429 /* Defer measuring/appraising kernel modules to READING_MODULE */ 430 if (read_id == READING_MODULE_COMPRESSED) { 431 must_appraise = 0; 432 goto out_locked; 433 } 434 435 if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ 436 pathname = ima_d_path(&file->f_path, &pathbuf, filename); 437 438 if (action & IMA_MEASURE) 439 ima_store_measurement(iint, file, pathname, 440 xattr_value, xattr_len, modsig, pcr, 441 template_desc); 442 if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) { 443 rc = ima_check_blacklist(iint, modsig, pcr); 444 if (rc != -EPERM) { 445 inode_lock(inode); 446 rc = ima_appraise_measurement(func, iint, file, 447 pathname, xattr_value, 448 xattr_len, modsig, 449 bprm_is_check); 450 inode_unlock(inode); 451 } 452 if (!rc) 453 rc = mmap_violation_check(func, file, &pathbuf, 454 &pathname, filename); 455 } 456 if (action & IMA_AUDIT) 457 ima_audit_measurement(iint, pathname); 458 459 if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO)) 460 rc = 0; 461 462 /* Ensure the digest was generated using an allowed algorithm */ 463 if (rc == 0 && must_appraise && allowed_algos != 0 && 464 (allowed_algos & (1U << hash_algo)) == 0) { 465 rc = -EACCES; 466 467 integrity_audit_msg(AUDIT_INTEGRITY_DATA, file_inode(file), 468 pathname, "collect_data", 469 "denied-hash-algorithm", rc, 0, rc); 470 } 471 out_locked: 472 if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) && 473 !(iint->flags & IMA_NEW_FILE)) 474 rc = -EACCES; 475 mutex_unlock(&iint->mutex); 476 kfree(xattr_value); 477 ima_free_modsig(modsig); 478 out: 479 if (pathbuf) 480 __putname(pathbuf); 481 if (must_appraise) { 482 if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE)) 483 return -EACCES; 484 if (file->f_mode & FMODE_WRITE) 485 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); 486 } 487 return 0; 488 } 489 490 /** 491 * ima_file_mmap - based on policy, collect/store measurement. 492 * @file: pointer to the file to be measured (May be NULL) 493 * @reqprot: protection requested by the application 494 * @prot: protection that will be applied by the kernel 495 * @flags: operational flags 496 * 497 * Measure files being mmapped executable based on the ima_must_measure() 498 * policy decision. 499 * 500 * On success return 0. On integrity appraisal error, assuming the file 501 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 502 */ 503 static int ima_file_mmap(struct file *file, unsigned long reqprot, 504 unsigned long prot, unsigned long flags) 505 { 506 struct lsm_prop prop; 507 int ret; 508 509 if (!file) 510 return 0; 511 512 security_current_getlsmprop_subj(&prop); 513 514 if (reqprot & PROT_EXEC) { 515 ret = process_measurement(file, current_cred(), &prop, NULL, 516 0, MAY_EXEC, MMAP_CHECK_REQPROT, 0, 517 false); 518 if (ret) 519 return ret; 520 } 521 522 if (prot & PROT_EXEC) 523 return process_measurement(file, current_cred(), &prop, NULL, 524 0, MAY_EXEC, MMAP_CHECK, 0, false); 525 526 return 0; 527 } 528 529 /** 530 * ima_file_mprotect - based on policy, limit mprotect change 531 * @vma: vm_area_struct protection is set to 532 * @reqprot: protection requested by the application 533 * @prot: protection that will be applied by the kernel 534 * 535 * Files can be mmap'ed read/write and later changed to execute to circumvent 536 * IMA's mmap appraisal policy rules. Due to locking issues (mmap semaphore 537 * would be taken before i_mutex), files can not be measured or appraised at 538 * this point. Eliminate this integrity gap by denying the mprotect 539 * PROT_EXECUTE change, if an mmap appraise policy rule exists. 540 * 541 * On mprotect change success, return 0. On failure, return -EACESS. 542 */ 543 static int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot, 544 unsigned long prot) 545 { 546 struct ima_template_desc *template = NULL; 547 struct file *file; 548 char filename[NAME_MAX]; 549 char *pathbuf = NULL; 550 const char *pathname = NULL; 551 struct inode *inode; 552 struct lsm_prop prop; 553 int result = 0; 554 int action; 555 int pcr; 556 557 /* Is mprotect making an mmap'ed file executable? */ 558 if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file || 559 !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC)) 560 return 0; 561 562 security_current_getlsmprop_subj(&prop); 563 inode = file_inode(vma->vm_file); 564 action = ima_get_action(file_mnt_idmap(vma->vm_file), inode, 565 current_cred(), &prop, MAY_EXEC, MMAP_CHECK, 566 &pcr, &template, NULL, NULL); 567 action |= ima_get_action(file_mnt_idmap(vma->vm_file), inode, 568 current_cred(), &prop, MAY_EXEC, 569 MMAP_CHECK_REQPROT, &pcr, &template, NULL, 570 NULL); 571 572 /* Is the mmap'ed file in policy? */ 573 if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK))) 574 return 0; 575 576 if (action & IMA_APPRAISE_SUBMASK) 577 result = -EPERM; 578 579 file = vma->vm_file; 580 pathname = ima_d_path(&file->f_path, &pathbuf, filename); 581 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname, 582 "collect_data", "failed-mprotect", result, 0, 583 result); 584 if (pathbuf) 585 __putname(pathbuf); 586 587 return result; 588 } 589 590 /** 591 * ima_bprm_check - based on policy, collect/store measurement. 592 * @bprm: contains the linux_binprm structure 593 * 594 * The OS protects against an executable file, already open for write, 595 * from being executed in deny_write_access() and an executable file, 596 * already open for execute, from being modified in get_write_access(). 597 * So we can be certain that what we verify and measure here is actually 598 * what is being executed. 599 * 600 * On success return 0. On integrity appraisal error, assuming the file 601 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 602 */ 603 static int ima_bprm_check(struct linux_binprm *bprm) 604 { 605 struct lsm_prop prop; 606 607 security_current_getlsmprop_subj(&prop); 608 return process_measurement(bprm->file, current_cred(), 609 &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0, 610 bprm->is_check); 611 } 612 613 /** 614 * ima_creds_check - based on policy, collect/store measurement. 615 * @bprm: contains the linux_binprm structure 616 * @file: contains the file descriptor of the binary being executed 617 * 618 * The OS protects against an executable file, already open for write, 619 * from being executed in deny_write_access() and an executable file, 620 * already open for execute, from being modified in get_write_access(). 621 * So we can be certain that what we verify and measure here is actually 622 * what is being executed. 623 * 624 * The difference from ima_bprm_check() is that ima_creds_check() is invoked 625 * only after determining the final binary to be executed without interpreter, 626 * and not when searching for intermediate binaries. The reason is that since 627 * commit 56305aa9b6fab ("exec: Compute file based creds only once"), the 628 * credentials to be applied to the process are calculated only at that stage 629 * (bprm_creds_from_file security hook instead of bprm_check_security). 630 * 631 * On success return 0. On integrity appraisal error, assuming the file 632 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 633 */ 634 static int ima_creds_check(struct linux_binprm *bprm, const struct file *file) 635 { 636 struct lsm_prop prop; 637 638 security_current_getlsmprop_subj(&prop); 639 return process_measurement((struct file *)file, bprm->cred, &prop, NULL, 640 0, MAY_EXEC, CREDS_CHECK, 0, false); 641 } 642 643 /** 644 * ima_bprm_creds_for_exec - collect/store/appraise measurement. 645 * @bprm: contains the linux_binprm structure 646 * 647 * Based on the IMA policy and the execveat(2) AT_EXECVE_CHECK flag, measure 648 * and appraise the integrity of a file to be executed by script interpreters. 649 * Unlike any of the other LSM hooks where the kernel enforces file integrity, 650 * enforcing file integrity is left up to the discretion of the script 651 * interpreter (userspace). 652 * 653 * On success return 0. On integrity appraisal error, assuming the file 654 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 655 */ 656 static int ima_bprm_creds_for_exec(struct linux_binprm *bprm) 657 { 658 /* 659 * As security_bprm_check() is called multiple times, both 660 * the script and the shebang interpreter are measured, appraised, 661 * and audited. Limit usage of this LSM hook to just measuring, 662 * appraising, and auditing the indirect script execution 663 * (e.g. ./sh example.sh). 664 */ 665 if (!bprm->is_check) 666 return 0; 667 668 return ima_bprm_check(bprm); 669 } 670 671 /** 672 * ima_file_check - based on policy, collect/store measurement. 673 * @file: pointer to the file to be measured 674 * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND 675 * 676 * Measure files based on the ima_must_measure() policy decision. 677 * 678 * On success return 0. On integrity appraisal error, assuming the file 679 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 680 */ 681 static int ima_file_check(struct file *file, int mask) 682 { 683 struct lsm_prop prop; 684 685 security_current_getlsmprop_subj(&prop); 686 return process_measurement(file, current_cred(), &prop, NULL, 0, 687 mask & (MAY_READ | MAY_WRITE | MAY_EXEC | 688 MAY_APPEND), FILE_CHECK, 0, false); 689 } 690 691 /* 692 * ima_reset_action_flags - invalidate action flags after a content change 693 * @inode: inode of the file whose content is about to be truncated 694 * 695 * Clear IMA_DONE_MASK so the file is re-collected, re-measured, 696 * re-audited, and re-appraised on next access. 697 */ 698 static void ima_reset_action_flags(struct inode *inode) 699 { 700 struct ima_iint_cache *iint; 701 702 if (!ima_policy_flag || !S_ISREG(inode->i_mode)) 703 return; 704 705 iint = ima_iint_find(inode); 706 if (!iint) 707 return; 708 709 mutex_lock(&iint->mutex); 710 iint->flags &= ~IMA_DONE_MASK; 711 iint->measured_pcrs = 0; 712 mutex_unlock(&iint->mutex); 713 return; 714 } 715 716 static int ima_path_truncate(const struct path *path) 717 { 718 ima_reset_action_flags(path->dentry->d_inode); 719 return 0; 720 } 721 722 static int ima_file_truncate(struct file *file) 723 { 724 ima_reset_action_flags(file_inode(file)); 725 return 0; 726 } 727 728 static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf, 729 size_t buf_size) 730 { 731 struct ima_iint_cache *iint = NULL, tmp_iint; 732 int rc, hash_algo; 733 734 if (ima_policy_flag) { 735 iint = ima_iint_find(inode); 736 if (iint) 737 mutex_lock(&iint->mutex); 738 } 739 740 if ((!iint || !(iint->flags & IMA_COLLECTED)) && file) { 741 if (iint) 742 mutex_unlock(&iint->mutex); 743 744 memset(&tmp_iint, 0, sizeof(tmp_iint)); 745 mutex_init(&tmp_iint.mutex); 746 747 rc = ima_collect_measurement(&tmp_iint, file, NULL, 0, 748 ima_hash_algo, NULL); 749 if (rc < 0) { 750 /* ima_hash could be allocated in case of failure. */ 751 if (rc != -ENOMEM) 752 kfree(tmp_iint.ima_hash); 753 754 return -EOPNOTSUPP; 755 } 756 757 iint = &tmp_iint; 758 mutex_lock(&iint->mutex); 759 } 760 761 if (!iint) 762 return -EOPNOTSUPP; 763 764 /* 765 * ima_file_hash can be called when ima_collect_measurement has still 766 * not been called, we might not always have a hash. 767 */ 768 if (!iint->ima_hash || !(iint->flags & IMA_COLLECTED)) { 769 mutex_unlock(&iint->mutex); 770 return -EOPNOTSUPP; 771 } 772 773 if (buf) { 774 size_t copied_size; 775 776 copied_size = min_t(size_t, iint->ima_hash->length, buf_size); 777 memcpy(buf, iint->ima_hash->digest, copied_size); 778 } 779 hash_algo = iint->ima_hash->algo; 780 mutex_unlock(&iint->mutex); 781 782 if (iint == &tmp_iint) 783 kfree(iint->ima_hash); 784 785 return hash_algo; 786 } 787 788 /** 789 * ima_file_hash - return a measurement of the file 790 * @file: pointer to the file 791 * @buf: buffer in which to store the hash 792 * @buf_size: length of the buffer 793 * 794 * On success, return the hash algorithm (as defined in the enum hash_algo). 795 * If buf is not NULL, this function also outputs the hash into buf. 796 * If the hash is larger than buf_size, then only buf_size bytes will be copied. 797 * It generally just makes sense to pass a buffer capable of holding the largest 798 * possible hash: IMA_MAX_DIGEST_SIZE. 799 * The file hash returned is based on the entire file, including the appended 800 * signature. 801 * 802 * If the measurement cannot be performed, return -EOPNOTSUPP. 803 * If the parameters are incorrect, return -EINVAL. 804 */ 805 int ima_file_hash(struct file *file, char *buf, size_t buf_size) 806 { 807 if (!file) 808 return -EINVAL; 809 810 return __ima_inode_hash(file_inode(file), file, buf, buf_size); 811 } 812 EXPORT_SYMBOL_GPL(ima_file_hash); 813 814 /** 815 * ima_inode_hash - return the stored measurement if the inode has been hashed 816 * and is in the iint cache. 817 * @inode: pointer to the inode 818 * @buf: buffer in which to store the hash 819 * @buf_size: length of the buffer 820 * 821 * On success, return the hash algorithm (as defined in the enum hash_algo). 822 * If buf is not NULL, this function also outputs the hash into buf. 823 * If the hash is larger than buf_size, then only buf_size bytes will be copied. 824 * It generally just makes sense to pass a buffer capable of holding the largest 825 * possible hash: IMA_MAX_DIGEST_SIZE. 826 * The hash returned is based on the entire contents, including the appended 827 * signature. 828 * 829 * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. 830 * If the parameters are incorrect, return -EINVAL. 831 */ 832 int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) 833 { 834 if (!inode) 835 return -EINVAL; 836 837 return __ima_inode_hash(inode, NULL, buf, buf_size); 838 } 839 EXPORT_SYMBOL_GPL(ima_inode_hash); 840 841 /** 842 * ima_post_create_tmpfile - mark newly created tmpfile as new 843 * @idmap: idmap of the mount the inode was found from 844 * @inode: inode of the newly created tmpfile 845 * 846 * No measuring, appraising or auditing of newly created tmpfiles is needed. 847 * Skip calling process_measurement(), but indicate which newly, created 848 * tmpfiles are in policy. 849 */ 850 static void ima_post_create_tmpfile(const struct mnt_idmap *idmap, 851 struct inode *inode) 852 853 { 854 struct ima_iint_cache *iint; 855 int must_appraise; 856 857 if (!ima_policy_flag || !S_ISREG(inode->i_mode)) 858 return; 859 860 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS, 861 FILE_CHECK); 862 if (!must_appraise) 863 return; 864 865 /* Nothing to do if we can't allocate memory */ 866 iint = ima_inode_get(inode); 867 if (!iint) 868 return; 869 870 /* needed for writing the security xattrs */ 871 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags); 872 iint->ima_file_status = INTEGRITY_PASS; 873 } 874 875 /** 876 * ima_post_path_mknod - mark as a new inode 877 * @idmap: idmap of the mount the inode was found from 878 * @dentry: newly created dentry 879 * 880 * Mark files created via the mknodat syscall as new, so that the 881 * file data can be written later. 882 */ 883 static void ima_post_path_mknod(const struct mnt_idmap *idmap, struct dentry *dentry) 884 { 885 struct ima_iint_cache *iint; 886 struct inode *inode = dentry->d_inode; 887 int must_appraise; 888 889 if (!ima_policy_flag || !S_ISREG(inode->i_mode)) 890 return; 891 892 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS, 893 FILE_CHECK); 894 if (!must_appraise) 895 return; 896 897 /* Nothing to do if we can't allocate memory */ 898 iint = ima_inode_get(inode); 899 if (!iint) 900 return; 901 902 /* needed for re-opening empty files */ 903 iint->flags |= IMA_NEW_FILE; 904 } 905 906 /** 907 * ima_read_file - pre-measure/appraise hook decision based on policy 908 * @file: pointer to the file to be measured/appraised/audit 909 * @read_id: caller identifier 910 * @contents: whether a subsequent call will be made to ima_post_read_file() 911 * 912 * Permit reading a file based on policy. The policy rules are written 913 * in terms of the policy identifier. Appraising the integrity of 914 * a file requires a file descriptor. 915 * 916 * For permission return 0, otherwise return -EACCES. 917 */ 918 static int ima_read_file(struct file *file, enum kernel_read_file_id read_id, 919 bool contents) 920 { 921 enum ima_hooks func; 922 struct lsm_prop prop; 923 924 /* 925 * Do devices using pre-allocated memory run the risk of the 926 * firmware being accessible to the device prior to the completion 927 * of IMA's signature verification any more than when using two 928 * buffers? It may be desirable to include the buffer address 929 * in this API and walk all the dma_map_single() mappings to check. 930 */ 931 932 /* 933 * There will be a call made to ima_post_read_file() with 934 * a filled buffer, so we don't need to perform an extra 935 * read early here. 936 */ 937 if (contents) 938 return 0; 939 940 /* Read entire file for all partial reads. */ 941 func = read_idmap[read_id] ?: FILE_CHECK; 942 security_current_getlsmprop_subj(&prop); 943 return process_measurement(file, current_cred(), &prop, NULL, 0, 944 MAY_READ, func, 0, false); 945 } 946 947 const int read_idmap[READING_MAX_ID] = { 948 [READING_FIRMWARE] = FIRMWARE_CHECK, 949 [READING_MODULE] = MODULE_CHECK, 950 [READING_MODULE_COMPRESSED] = MODULE_CHECK, 951 [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, 952 [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK, 953 [READING_POLICY] = POLICY_CHECK 954 }; 955 956 /** 957 * ima_post_read_file - in memory collect/appraise/audit measurement 958 * @file: pointer to the file to be measured/appraised/audit 959 * @buf: pointer to in memory file contents 960 * @size: size of in memory file contents 961 * @read_id: caller identifier 962 * 963 * Measure/appraise/audit in memory file based on policy. Policy rules 964 * are written in terms of a policy identifier. 965 * 966 * On success return 0. On integrity appraisal error, assuming the file 967 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 968 */ 969 static int ima_post_read_file(struct file *file, char *buf, loff_t size, 970 enum kernel_read_file_id read_id) 971 { 972 enum ima_hooks func; 973 struct lsm_prop prop; 974 975 /* permit signed certs */ 976 if (!file && read_id == READING_X509_CERTIFICATE) 977 return 0; 978 979 if (!file || !buf || size == 0) { /* should never happen */ 980 if (ima_appraise & IMA_APPRAISE_ENFORCE) 981 return -EACCES; 982 return 0; 983 } 984 985 func = read_idmap[read_id] ?: FILE_CHECK; 986 security_current_getlsmprop_subj(&prop); 987 return process_measurement(file, current_cred(), &prop, buf, size, 988 MAY_READ, func, read_id, false); 989 } 990 991 /** 992 * ima_load_data - appraise decision based on policy 993 * @id: kernel load data caller identifier 994 * @contents: whether the full contents will be available in a later 995 * call to ima_post_load_data(). 996 * 997 * Callers of this LSM hook can not measure, appraise, or audit the 998 * data provided by userspace. Enforce policy rules requiring a file 999 * signature (eg. kexec'ed kernel image). 1000 * 1001 * For permission return 0, otherwise return -EACCES. 1002 */ 1003 static int ima_load_data(enum kernel_load_data_id id, bool contents) 1004 { 1005 bool ima_enforce, sig_enforce; 1006 1007 ima_enforce = 1008 (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE; 1009 1010 switch (id) { 1011 case LOADING_KEXEC_IMAGE: 1012 if (IS_ENABLED(CONFIG_KEXEC_SIG) && arch_get_secureboot()) { 1013 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); 1014 return -EACCES; 1015 } 1016 1017 if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) { 1018 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); 1019 return -EACCES; /* INTEGRITY_UNKNOWN */ 1020 } 1021 break; 1022 case LOADING_FIRMWARE: 1023 if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) { 1024 pr_err("Prevent firmware sysfs fallback loading.\n"); 1025 return -EACCES; /* INTEGRITY_UNKNOWN */ 1026 } 1027 break; 1028 case LOADING_MODULE: 1029 sig_enforce = is_module_sig_enforced(); 1030 1031 if (ima_enforce && (!sig_enforce 1032 && (ima_appraise & IMA_APPRAISE_MODULES))) { 1033 pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); 1034 return -EACCES; /* INTEGRITY_UNKNOWN */ 1035 } 1036 break; 1037 default: 1038 break; 1039 } 1040 return 0; 1041 } 1042 1043 /** 1044 * ima_post_load_data - appraise decision based on policy 1045 * @buf: pointer to in memory file contents 1046 * @size: size of in memory file contents 1047 * @load_id: kernel load data caller identifier 1048 * @description: @load_id-specific description of contents 1049 * 1050 * Measure/appraise/audit in memory buffer based on policy. Policy rules 1051 * are written in terms of a policy identifier. 1052 * 1053 * On success return 0. On integrity appraisal error, assuming the file 1054 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES. 1055 */ 1056 static int ima_post_load_data(char *buf, loff_t size, 1057 enum kernel_load_data_id load_id, 1058 char *description) 1059 { 1060 if (load_id == LOADING_FIRMWARE) { 1061 if ((ima_appraise & IMA_APPRAISE_FIRMWARE) && 1062 (ima_appraise & IMA_APPRAISE_ENFORCE)) { 1063 pr_err("Prevent firmware loading_store.\n"); 1064 return -EACCES; /* INTEGRITY_UNKNOWN */ 1065 } 1066 return 0; 1067 } 1068 1069 /* 1070 * Measure the init_module syscall buffer containing the ELF image. 1071 */ 1072 if (load_id == LOADING_MODULE) 1073 ima_measure_critical_data("modules", "init_module", 1074 buf, size, true, NULL, 0); 1075 1076 return 0; 1077 } 1078 1079 /** 1080 * process_buffer_measurement - Measure the buffer or the buffer data hash 1081 * @idmap: idmap of the mount the inode was found from 1082 * @inode: inode associated with the object being measured (NULL for KEY_CHECK) 1083 * @buf: pointer to the buffer that needs to be added to the log. 1084 * @size: size of buffer(in bytes). 1085 * @eventname: event name to be used for the buffer entry. 1086 * @func: IMA hook 1087 * @pcr: pcr to extend the measurement 1088 * @func_data: func specific data, may be NULL 1089 * @buf_hash: measure buffer data hash 1090 * @digest: buffer digest will be written to 1091 * @digest_len: buffer length 1092 * 1093 * Based on policy, either the buffer data or buffer data hash is measured 1094 * 1095 * Return: 0 if the buffer has been successfully measured, 1 if the digest 1096 * has been written to the passed location but not added to a measurement entry, 1097 * a negative value otherwise. 1098 */ 1099 int process_buffer_measurement(const struct mnt_idmap *idmap, 1100 struct inode *inode, const void *buf, int size, 1101 const char *eventname, enum ima_hooks func, 1102 int pcr, const char *func_data, 1103 bool buf_hash, u8 *digest, size_t digest_len) 1104 { 1105 int ret = 0; 1106 const char *audit_cause = "ENOMEM"; 1107 struct ima_template_entry *entry = NULL; 1108 struct ima_iint_cache iint = {}; 1109 struct ima_event_data event_data = {.iint = &iint, 1110 .filename = eventname, 1111 .buf = buf, 1112 .buf_len = size}; 1113 struct ima_template_desc *template; 1114 struct ima_max_digest_data hash; 1115 struct ima_digest_data *hash_hdr = container_of(&hash.hdr, 1116 struct ima_digest_data, hdr); 1117 char digest_hash[IMA_MAX_DIGEST_SIZE]; 1118 int digest_hash_len = hash_digest_size[ima_hash_algo]; 1119 int violation = 0; 1120 int action = 0; 1121 struct lsm_prop prop; 1122 1123 if (digest && digest_len < digest_hash_len) 1124 return -EINVAL; 1125 1126 if (!ima_policy_flag && !digest) 1127 return -ENOENT; 1128 1129 template = ima_template_desc_buf(); 1130 if (!template) { 1131 ret = -EINVAL; 1132 audit_cause = "ima_template_desc_buf"; 1133 goto out; 1134 } 1135 1136 /* 1137 * Both LSM hooks and auxiliary based buffer measurements are 1138 * based on policy. To avoid code duplication, differentiate 1139 * between the LSM hooks and auxiliary buffer measurements, 1140 * retrieving the policy rule information only for the LSM hook 1141 * buffer measurements. 1142 */ 1143 if (func) { 1144 security_current_getlsmprop_subj(&prop); 1145 action = ima_get_action(idmap, inode, current_cred(), 1146 &prop, 0, func, &pcr, &template, 1147 func_data, NULL); 1148 if (!(action & IMA_MEASURE) && !digest) 1149 return -ENOENT; 1150 } 1151 1152 if (!pcr) 1153 pcr = CONFIG_IMA_MEASURE_PCR_IDX; 1154 1155 iint.ima_hash = hash_hdr; 1156 iint.ima_hash->algo = ima_hash_algo; 1157 iint.ima_hash->length = hash_digest_size[ima_hash_algo]; 1158 1159 ret = ima_calc_buffer_hash(buf, size, iint.ima_hash); 1160 if (ret < 0) { 1161 audit_cause = "hashing_error"; 1162 goto out; 1163 } 1164 1165 if (buf_hash) { 1166 memcpy(digest_hash, hash_hdr->digest, digest_hash_len); 1167 1168 ret = ima_calc_buffer_hash(digest_hash, digest_hash_len, 1169 iint.ima_hash); 1170 if (ret < 0) { 1171 audit_cause = "hashing_error"; 1172 goto out; 1173 } 1174 1175 event_data.buf = digest_hash; 1176 event_data.buf_len = digest_hash_len; 1177 } 1178 1179 if (digest) 1180 memcpy(digest, iint.ima_hash->digest, digest_hash_len); 1181 1182 if (!ima_policy_flag || (func && !(action & IMA_MEASURE))) 1183 return 1; 1184 1185 ret = ima_alloc_init_template(&event_data, &entry, template); 1186 if (ret < 0) { 1187 audit_cause = "alloc_entry"; 1188 goto out; 1189 } 1190 1191 ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr); 1192 if (ret < 0) { 1193 audit_cause = "store_entry"; 1194 ima_free_template_entry(entry); 1195 } 1196 1197 out: 1198 if (ret < 0) 1199 integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, eventname, 1200 func_measure_str(func), 1201 audit_cause, ret, 0, ret); 1202 1203 return ret; 1204 } 1205 1206 /** 1207 * ima_kexec_cmdline - measure kexec cmdline boot args 1208 * @kernel_fd: file descriptor of the kexec kernel being loaded 1209 * @buf: pointer to buffer 1210 * @size: size of buffer 1211 * 1212 * Buffers can only be measured, not appraised. 1213 */ 1214 void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) 1215 { 1216 if (!buf || !size) 1217 return; 1218 1219 CLASS(fd, f)(kernel_fd); 1220 if (fd_empty(f)) 1221 return; 1222 1223 process_buffer_measurement(file_mnt_idmap(fd_file(f)), file_inode(fd_file(f)), 1224 buf, size, "kexec-cmdline", KEXEC_CMDLINE, 0, 1225 NULL, false, NULL, 0); 1226 } 1227 1228 /** 1229 * ima_measure_critical_data - measure kernel integrity critical data 1230 * @event_label: unique event label for grouping and limiting critical data 1231 * @event_name: event name for the record in the IMA measurement list 1232 * @buf: pointer to buffer data 1233 * @buf_len: length of buffer data (in bytes) 1234 * @hash: measure buffer data hash 1235 * @digest: buffer digest will be written to 1236 * @digest_len: buffer length 1237 * 1238 * Measure data critical to the integrity of the kernel into the IMA log 1239 * and extend the pcr. Examples of critical data could be various data 1240 * structures, policies, and states stored in kernel memory that can 1241 * impact the integrity of the system. 1242 * 1243 * Return: 0 if the buffer has been successfully measured, 1 if the digest 1244 * has been written to the passed location but not added to a measurement entry, 1245 * a negative value otherwise. 1246 */ 1247 int ima_measure_critical_data(const char *event_label, 1248 const char *event_name, 1249 const void *buf, size_t buf_len, 1250 bool hash, u8 *digest, size_t digest_len) 1251 { 1252 if (!event_name || !event_label || !buf || !buf_len) 1253 return -ENOPARAM; 1254 1255 return process_buffer_measurement(&nop_mnt_idmap, NULL, buf, buf_len, 1256 event_name, CRITICAL_DATA, 0, 1257 event_label, hash, digest, 1258 digest_len); 1259 } 1260 EXPORT_SYMBOL_GPL(ima_measure_critical_data); 1261 1262 /** 1263 * ima_measure_raw_policy - Measure the raw policy write buffer 1264 * @buf: pointer to the buffer containing the raw policy data 1265 * @buf_len: size of the buffer 1266 * 1267 * Measure the raw policy buffer sent to the IMA policy securityfs file. The 1268 * buffer is written from userspace, and the measurement is performed before 1269 * parsing it. This measurement includes any data written on the policy file 1270 * such as malformed policy rules and comments. 1271 * 1272 * Return 0 on success, a negative value otherwise. 1273 */ 1274 int ima_measure_raw_policy(const char *buf, size_t buf_len) 1275 { 1276 if (!buf || !buf_len) 1277 return -EINVAL; 1278 1279 return process_buffer_measurement(&nop_mnt_idmap, NULL, buf, buf_len, 1280 "ima_policy_written", POLICY_CHECK, 1281 0, NULL, false, NULL, 0); 1282 } 1283 1284 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS 1285 1286 /** 1287 * ima_kernel_module_request - Prevent crypto-pkcs1(rsa,*) requests 1288 * @kmod_name: kernel module name 1289 * 1290 * Avoid a verification loop where verifying the signature of the modprobe 1291 * binary requires executing modprobe itself. Since the modprobe iint->mutex 1292 * is already held when the signature verification is performed, a deadlock 1293 * occurs as soon as modprobe is executed within the critical region, since 1294 * the same lock cannot be taken again. 1295 * 1296 * This happens when public_key_verify_signature(), in case of RSA algorithm, 1297 * use alg_name to store internal information in order to construct an 1298 * algorithm on the fly, but crypto_larval_lookup() will try to use alg_name 1299 * in order to load a kernel module with same name. 1300 * 1301 * Since we don't have any real "crypto-pkcs1(rsa,*)" kernel modules, 1302 * we are safe to fail such module request from crypto_larval_lookup(), and 1303 * avoid the verification loop. 1304 * 1305 * Return: Zero if it is safe to load the kernel module, -EINVAL otherwise. 1306 */ 1307 static int ima_kernel_module_request(char *kmod_name) 1308 { 1309 if (strncmp(kmod_name, "crypto-pkcs1(rsa,", 17) == 0) 1310 return -EINVAL; 1311 1312 return 0; 1313 } 1314 1315 #endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */ 1316 1317 static int __init init_ima(void) 1318 { 1319 int error; 1320 1321 /*Note that turning IMA off is intentionally limited to kdump kernel.*/ 1322 if (ima_disabled && is_kdump_kernel()) { 1323 pr_info("IMA functionality is disabled"); 1324 return 0; 1325 } 1326 1327 ima_appraise_parse_cmdline(); 1328 ima_init_template_list(); 1329 hash_setup(CONFIG_IMA_DEFAULT_HASH); 1330 error = ima_init(); 1331 1332 if (error && strcmp(hash_algo_name[ima_hash_algo], 1333 CONFIG_IMA_DEFAULT_HASH) != 0) { 1334 pr_info("Allocating %s failed, going to use default hash algorithm %s\n", 1335 hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH); 1336 hash_setup_done = 0; 1337 hash_setup(CONFIG_IMA_DEFAULT_HASH); 1338 error = ima_init(); 1339 } 1340 1341 if (error) 1342 return error; 1343 1344 error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier); 1345 if (error) 1346 pr_warn("Couldn't register LSM notifier, error %d\n", error); 1347 1348 if (!error) 1349 ima_update_policy_flags(); 1350 1351 return error; 1352 } 1353 1354 static struct security_hook_list ima_hooks[] __ro_after_init = { 1355 LSM_HOOK_INIT(bprm_check_security, ima_bprm_check), 1356 LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec), 1357 LSM_HOOK_INIT(bprm_creds_from_file, ima_creds_check), 1358 LSM_HOOK_INIT(file_post_open, ima_file_check), 1359 LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile), 1360 LSM_HOOK_INIT(file_release, ima_file_free), 1361 LSM_HOOK_INIT(mmap_file, ima_file_mmap), 1362 LSM_HOOK_INIT(file_mprotect, ima_file_mprotect), 1363 LSM_HOOK_INIT(file_truncate, ima_file_truncate), 1364 LSM_HOOK_INIT(kernel_load_data, ima_load_data), 1365 LSM_HOOK_INIT(kernel_post_load_data, ima_post_load_data), 1366 LSM_HOOK_INIT(kernel_read_file, ima_read_file), 1367 LSM_HOOK_INIT(kernel_post_read_file, ima_post_read_file), 1368 LSM_HOOK_INIT(path_post_mknod, ima_post_path_mknod), 1369 LSM_HOOK_INIT(path_truncate, ima_path_truncate), 1370 #ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS 1371 LSM_HOOK_INIT(key_post_create_or_update, ima_post_key_create_or_update), 1372 #endif 1373 #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS 1374 LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), 1375 #endif 1376 LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), 1377 }; 1378 1379 static const struct lsm_id ima_lsmid = { 1380 .name = "ima", 1381 .id = LSM_ID_IMA, 1382 }; 1383 1384 static int __init init_ima_lsm(void) 1385 { 1386 ima_iintcache_init(); 1387 security_add_hooks(ima_hooks, ARRAY_SIZE(ima_hooks), &ima_lsmid); 1388 init_ima_appraise_lsm(&ima_lsmid); 1389 return 0; 1390 } 1391 1392 struct lsm_blob_sizes ima_blob_sizes __ro_after_init = { 1393 .lbs_inode = sizeof(struct ima_iint_cache *), 1394 }; 1395 1396 DEFINE_LSM(ima) = { 1397 .id = &ima_lsmid, 1398 .init = init_ima_lsm, 1399 .order = LSM_ORDER_LAST, 1400 .blobs = &ima_blob_sizes, 1401 /* Start IMA after the TPM is available */ 1402 #ifndef CONFIG_IMA_INIT_LATE_SYNC 1403 .initcall_late = init_ima, 1404 #else 1405 .initcall_late_sync = init_ima, 1406 #endif 1407 }; 1408