1 // SPDX-License-Identifier: GPL-2.0-only
3 * Integrity Measurement Architecture
5 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
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>
14 * implements the IMA hooks: ima_bprm_check, ima_file_mmap,
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/iversion.h>
32 #ifdef CONFIG_IMA_APPRAISE
33 int ima_appraise = IMA_APPRAISE_ENFORCE;
38 int __ro_after_init ima_hash_algo = HASH_ALGO_SHA1;
39 static int hash_setup_done;
41 static struct notifier_block ima_lsm_policy_notifier = {
42 .notifier_call = ima_lsm_policy_change,
45 static int __init hash_setup(char *str)
47 struct ima_template_desc *template_desc = ima_template_desc_current();
53 if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
54 if (strncmp(str, "sha1", 4) == 0) {
55 ima_hash_algo = HASH_ALGO_SHA1;
56 } else if (strncmp(str, "md5", 3) == 0) {
57 ima_hash_algo = HASH_ALGO_MD5;
59 pr_err("invalid hash algorithm \"%s\" for template \"%s\"",
60 str, IMA_TEMPLATE_IMA_NAME);
66 i = match_string(hash_algo_name, HASH_ALGO__LAST, str);
68 pr_err("invalid hash algorithm \"%s\"", str);
77 __setup("ima_hash=", hash_setup);
79 enum hash_algo ima_get_current_hash_algo(void)
84 /* Prevent mmap'ing a file execute that is already mmap'ed write */
85 static int mmap_violation_check(enum ima_hooks func, struct file *file,
86 char **pathbuf, const char **pathname,
92 if ((func == MMAP_CHECK || func == MMAP_CHECK_REQPROT) &&
93 mapping_writably_mapped(file->f_mapping)) {
95 inode = file_inode(file);
97 if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */
98 *pathname = ima_d_path(&file->f_path, pathbuf,
100 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname,
101 "mmap_file", "mmapped_writers", rc, 0);
107 * ima_rdwr_violation_check
109 * Only invalidate the PCR for measured files:
110 * - Opening a file for write when already open for read,
111 * results in a time of measure, time of use (ToMToU) error.
112 * - Opening a file for read when already open for write,
113 * could result in a file measurement error.
116 static void ima_rdwr_violation_check(struct file *file,
117 struct integrity_iint_cache *iint,
120 const char **pathname,
123 struct inode *inode = file_inode(file);
124 fmode_t mode = file->f_mode;
125 bool send_tomtou = false, send_writers = false;
127 if (mode & FMODE_WRITE) {
128 if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
130 iint = integrity_iint_find(inode);
131 /* IMA_MEASURE is set from reader side */
132 if (iint && test_bit(IMA_MUST_MEASURE,
133 &iint->atomic_flags))
138 set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
139 if (inode_is_open_for_write(inode) && must_measure)
143 if (!send_tomtou && !send_writers)
146 *pathname = ima_d_path(&file->f_path, pathbuf, filename);
149 ima_add_violation(file, *pathname, iint,
150 "invalid_pcr", "ToMToU");
152 ima_add_violation(file, *pathname, iint,
153 "invalid_pcr", "open_writers");
156 static void ima_check_last_writer(struct integrity_iint_cache *iint,
157 struct inode *inode, struct file *file)
159 fmode_t mode = file->f_mode;
162 if (!(mode & FMODE_WRITE))
165 mutex_lock(&iint->mutex);
166 if (atomic_read(&inode->i_writecount) == 1) {
167 update = test_and_clear_bit(IMA_UPDATE_XATTR,
168 &iint->atomic_flags);
169 if (!IS_I_VERSION(inode) ||
170 !inode_eq_iversion(inode, iint->version) ||
171 (iint->flags & IMA_NEW_FILE)) {
172 iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
173 iint->measured_pcrs = 0;
175 ima_update_xattr(iint, file);
178 mutex_unlock(&iint->mutex);
182 * ima_file_free - called on __fput()
183 * @file: pointer to file structure being freed
185 * Flag files that changed, based on i_version
187 void ima_file_free(struct file *file)
189 struct inode *inode = file_inode(file);
190 struct integrity_iint_cache *iint;
192 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
195 iint = integrity_iint_find(inode);
199 ima_check_last_writer(iint, inode, file);
202 static int process_measurement(struct file *file, const struct cred *cred,
203 u32 secid, char *buf, loff_t size, int mask,
206 struct inode *inode = file_inode(file);
207 struct integrity_iint_cache *iint = NULL;
208 struct ima_template_desc *template_desc = NULL;
209 char *pathbuf = NULL;
210 char filename[NAME_MAX];
211 const char *pathname = NULL;
212 int rc = 0, action, must_appraise = 0;
213 int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
214 struct evm_ima_xattr_data *xattr_value = NULL;
215 struct modsig *modsig = NULL;
217 bool violation_check;
218 enum hash_algo hash_algo;
219 unsigned int allowed_algos = 0;
221 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
224 /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
225 * bitmask based on the appraise/audit/measurement policy.
226 * Included is the appraise submask.
228 action = ima_get_action(file_mnt_idmap(file), inode, cred, secid,
229 mask, func, &pcr, &template_desc, NULL,
231 violation_check = ((func == FILE_CHECK || func == MMAP_CHECK ||
232 func == MMAP_CHECK_REQPROT) &&
233 (ima_policy_flag & IMA_MEASURE));
234 if (!action && !violation_check)
237 must_appraise = action & IMA_APPRAISE;
239 /* Is the appraise rule hook specific? */
240 if (action & IMA_FILE_APPRAISE)
246 iint = integrity_inode_get(inode);
251 if (!rc && violation_check)
252 ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
253 &pathbuf, &pathname, filename);
262 mutex_lock(&iint->mutex);
264 if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
265 /* reset appraisal flags if ima_inode_post_setattr was called */
266 iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
267 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
268 IMA_NONACTION_FLAGS);
271 * Re-evaulate the file if either the xattr has changed or the
272 * kernel has no way of detecting file change on the filesystem.
273 * (Limited to privileged mounted filesystems.)
275 if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) ||
276 ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
277 !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) &&
278 !(action & IMA_FAIL_UNVERIFIABLE_SIGS))) {
279 iint->flags &= ~IMA_DONE_MASK;
280 iint->measured_pcrs = 0;
283 /* Determine if already appraised/measured based on bitmask
284 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
285 * IMA_AUDIT, IMA_AUDITED)
287 iint->flags |= action;
288 action &= IMA_DO_MASK;
289 action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
291 /* If target pcr is already measured, unset IMA_MEASURE action */
292 if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
293 action ^= IMA_MEASURE;
295 /* HASH sets the digital signature and update flags, nothing else */
296 if ((action & IMA_HASH) &&
297 !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
298 xattr_len = ima_read_xattr(file_dentry(file),
299 &xattr_value, xattr_len);
300 if ((xattr_value && xattr_len > 2) &&
301 (xattr_value->type == EVM_IMA_XATTR_DIGSIG))
302 set_bit(IMA_DIGSIG, &iint->atomic_flags);
303 iint->flags |= IMA_HASHED;
305 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
308 /* Nothing to do, just return existing appraised status */
311 rc = mmap_violation_check(func, file, &pathbuf,
312 &pathname, filename);
314 rc = ima_get_cache_status(iint, func);
319 if ((action & IMA_APPRAISE_SUBMASK) ||
320 strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
321 /* read 'security.ima' */
322 xattr_len = ima_read_xattr(file_dentry(file),
323 &xattr_value, xattr_len);
326 * Read the appended modsig if allowed by the policy, and allow
327 * an additional measurement list entry, if needed, based on the
328 * template format and whether the file was already measured.
330 if (iint->flags & IMA_MODSIG_ALLOWED) {
331 rc = ima_read_modsig(func, buf, size, &modsig);
333 if (!rc && ima_template_has_modsig(template_desc) &&
334 iint->flags & IMA_MEASURED)
335 action |= IMA_MEASURE;
339 hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
341 rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
342 if (rc != 0 && rc != -EBADF && rc != -EINVAL)
345 if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */
346 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
348 if (action & IMA_MEASURE)
349 ima_store_measurement(iint, file, pathname,
350 xattr_value, xattr_len, modsig, pcr,
352 if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
353 rc = ima_check_blacklist(iint, modsig, pcr);
356 rc = ima_appraise_measurement(func, iint, file,
357 pathname, xattr_value,
362 rc = mmap_violation_check(func, file, &pathbuf,
363 &pathname, filename);
365 if (action & IMA_AUDIT)
366 ima_audit_measurement(iint, pathname);
368 if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
371 /* Ensure the digest was generated using an allowed algorithm */
372 if (rc == 0 && must_appraise && allowed_algos != 0 &&
373 (allowed_algos & (1U << hash_algo)) == 0) {
376 integrity_audit_msg(AUDIT_INTEGRITY_DATA, file_inode(file),
377 pathname, "collect_data",
378 "denied-hash-algorithm", rc, 0);
381 if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
382 !(iint->flags & IMA_NEW_FILE))
384 mutex_unlock(&iint->mutex);
386 ima_free_modsig(modsig);
391 if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
393 if (file->f_mode & FMODE_WRITE)
394 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
400 * ima_file_mmap - based on policy, collect/store measurement.
401 * @file: pointer to the file to be measured (May be NULL)
402 * @reqprot: protection requested by the application
403 * @prot: protection that will be applied by the kernel
404 * @flags: operational flags
406 * Measure files being mmapped executable based on the ima_must_measure()
409 * On success return 0. On integrity appraisal error, assuming the file
410 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
412 int ima_file_mmap(struct file *file, unsigned long reqprot,
413 unsigned long prot, unsigned long flags)
421 security_current_getsecid_subj(&secid);
423 if (reqprot & PROT_EXEC) {
424 ret = process_measurement(file, current_cred(), secid, NULL,
425 0, MAY_EXEC, MMAP_CHECK_REQPROT);
430 if (prot & PROT_EXEC)
431 return process_measurement(file, current_cred(), secid, NULL,
432 0, MAY_EXEC, MMAP_CHECK);
438 * ima_file_mprotect - based on policy, limit mprotect change
439 * @vma: vm_area_struct protection is set to
440 * @prot: contains the protection that will be applied by the kernel.
442 * Files can be mmap'ed read/write and later changed to execute to circumvent
443 * IMA's mmap appraisal policy rules. Due to locking issues (mmap semaphore
444 * would be taken before i_mutex), files can not be measured or appraised at
445 * this point. Eliminate this integrity gap by denying the mprotect
446 * PROT_EXECUTE change, if an mmap appraise policy rule exists.
448 * On mprotect change success, return 0. On failure, return -EACESS.
450 int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
452 struct ima_template_desc *template = NULL;
454 char filename[NAME_MAX];
455 char *pathbuf = NULL;
456 const char *pathname = NULL;
463 /* Is mprotect making an mmap'ed file executable? */
464 if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
465 !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
468 security_current_getsecid_subj(&secid);
469 inode = file_inode(vma->vm_file);
470 action = ima_get_action(file_mnt_idmap(vma->vm_file), inode,
471 current_cred(), secid, MAY_EXEC, MMAP_CHECK,
472 &pcr, &template, NULL, NULL);
473 action |= ima_get_action(file_mnt_idmap(vma->vm_file), inode,
474 current_cred(), secid, MAY_EXEC,
475 MMAP_CHECK_REQPROT, &pcr, &template, NULL,
478 /* Is the mmap'ed file in policy? */
479 if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
482 if (action & IMA_APPRAISE_SUBMASK)
486 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
487 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname,
488 "collect_data", "failed-mprotect", result, 0);
496 * ima_bprm_check - based on policy, collect/store measurement.
497 * @bprm: contains the linux_binprm structure
499 * The OS protects against an executable file, already open for write,
500 * from being executed in deny_write_access() and an executable file,
501 * already open for execute, from being modified in get_write_access().
502 * So we can be certain that what we verify and measure here is actually
503 * what is being executed.
505 * On success return 0. On integrity appraisal error, assuming the file
506 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
508 int ima_bprm_check(struct linux_binprm *bprm)
513 security_current_getsecid_subj(&secid);
514 ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
515 MAY_EXEC, BPRM_CHECK);
519 security_cred_getsecid(bprm->cred, &secid);
520 return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
521 MAY_EXEC, CREDS_CHECK);
525 * ima_file_check - based on policy, collect/store measurement.
526 * @file: pointer to the file to be measured
527 * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
529 * Measure files based on the ima_must_measure() policy decision.
531 * On success return 0. On integrity appraisal error, assuming the file
532 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
534 int ima_file_check(struct file *file, int mask)
538 security_current_getsecid_subj(&secid);
539 return process_measurement(file, current_cred(), secid, NULL, 0,
540 mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
541 MAY_APPEND), FILE_CHECK);
543 EXPORT_SYMBOL_GPL(ima_file_check);
545 static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,
548 struct integrity_iint_cache *iint = NULL, tmp_iint;
551 if (ima_policy_flag) {
552 iint = integrity_iint_find(inode);
554 mutex_lock(&iint->mutex);
557 if ((!iint || !(iint->flags & IMA_COLLECTED)) && file) {
559 mutex_unlock(&iint->mutex);
561 memset(&tmp_iint, 0, sizeof(tmp_iint));
562 tmp_iint.inode = inode;
563 mutex_init(&tmp_iint.mutex);
565 rc = ima_collect_measurement(&tmp_iint, file, NULL, 0,
566 ima_hash_algo, NULL);
568 /* ima_hash could be allocated in case of failure. */
570 kfree(tmp_iint.ima_hash);
576 mutex_lock(&iint->mutex);
583 * ima_file_hash can be called when ima_collect_measurement has still
584 * not been called, we might not always have a hash.
586 if (!iint->ima_hash || !(iint->flags & IMA_COLLECTED)) {
587 mutex_unlock(&iint->mutex);
594 copied_size = min_t(size_t, iint->ima_hash->length, buf_size);
595 memcpy(buf, iint->ima_hash->digest, copied_size);
597 hash_algo = iint->ima_hash->algo;
598 mutex_unlock(&iint->mutex);
600 if (iint == &tmp_iint)
601 kfree(iint->ima_hash);
607 * ima_file_hash - return a measurement of the file
608 * @file: pointer to the file
609 * @buf: buffer in which to store the hash
610 * @buf_size: length of the buffer
612 * On success, return the hash algorithm (as defined in the enum hash_algo).
613 * If buf is not NULL, this function also outputs the hash into buf.
614 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
615 * It generally just makes sense to pass a buffer capable of holding the largest
616 * possible hash: IMA_MAX_DIGEST_SIZE.
617 * The file hash returned is based on the entire file, including the appended
620 * If the measurement cannot be performed, return -EOPNOTSUPP.
621 * If the parameters are incorrect, return -EINVAL.
623 int ima_file_hash(struct file *file, char *buf, size_t buf_size)
628 return __ima_inode_hash(file_inode(file), file, buf, buf_size);
630 EXPORT_SYMBOL_GPL(ima_file_hash);
633 * ima_inode_hash - return the stored measurement if the inode has been hashed
634 * and is in the iint cache.
635 * @inode: pointer to the inode
636 * @buf: buffer in which to store the hash
637 * @buf_size: length of the buffer
639 * On success, return the hash algorithm (as defined in the enum hash_algo).
640 * If buf is not NULL, this function also outputs the hash into buf.
641 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
642 * It generally just makes sense to pass a buffer capable of holding the largest
643 * possible hash: IMA_MAX_DIGEST_SIZE.
644 * The hash returned is based on the entire contents, including the appended
647 * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP.
648 * If the parameters are incorrect, return -EINVAL.
650 int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
655 return __ima_inode_hash(inode, NULL, buf, buf_size);
657 EXPORT_SYMBOL_GPL(ima_inode_hash);
660 * ima_post_create_tmpfile - mark newly created tmpfile as new
661 * @idmap: idmap of the mount the inode was found from
662 * @inode: inode of the newly created tmpfile
664 * No measuring, appraising or auditing of newly created tmpfiles is needed.
665 * Skip calling process_measurement(), but indicate which newly, created
666 * tmpfiles are in policy.
668 void ima_post_create_tmpfile(struct mnt_idmap *idmap,
671 struct integrity_iint_cache *iint;
674 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
677 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS,
682 /* Nothing to do if we can't allocate memory */
683 iint = integrity_inode_get(inode);
687 /* needed for writing the security xattrs */
688 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
689 iint->ima_file_status = INTEGRITY_PASS;
693 * ima_post_path_mknod - mark as a new inode
694 * @idmap: idmap of the mount the inode was found from
695 * @dentry: newly created dentry
697 * Mark files created via the mknodat syscall as new, so that the
698 * file data can be written later.
700 void ima_post_path_mknod(struct mnt_idmap *idmap,
701 struct dentry *dentry)
703 struct integrity_iint_cache *iint;
704 struct inode *inode = dentry->d_inode;
707 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
710 must_appraise = ima_must_appraise(idmap, inode, MAY_ACCESS,
715 /* Nothing to do if we can't allocate memory */
716 iint = integrity_inode_get(inode);
720 /* needed for re-opening empty files */
721 iint->flags |= IMA_NEW_FILE;
725 * ima_read_file - pre-measure/appraise hook decision based on policy
726 * @file: pointer to the file to be measured/appraised/audit
727 * @read_id: caller identifier
728 * @contents: whether a subsequent call will be made to ima_post_read_file()
730 * Permit reading a file based on policy. The policy rules are written
731 * in terms of the policy identifier. Appraising the integrity of
732 * a file requires a file descriptor.
734 * For permission return 0, otherwise return -EACCES.
736 int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
743 * Do devices using pre-allocated memory run the risk of the
744 * firmware being accessible to the device prior to the completion
745 * of IMA's signature verification any more than when using two
746 * buffers? It may be desirable to include the buffer address
747 * in this API and walk all the dma_map_single() mappings to check.
751 * There will be a call made to ima_post_read_file() with
752 * a filled buffer, so we don't need to perform an extra
758 /* Read entire file for all partial reads. */
759 func = read_idmap[read_id] ?: FILE_CHECK;
760 security_current_getsecid_subj(&secid);
761 return process_measurement(file, current_cred(), secid, NULL,
765 const int read_idmap[READING_MAX_ID] = {
766 [READING_FIRMWARE] = FIRMWARE_CHECK,
767 [READING_MODULE] = MODULE_CHECK,
768 [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
769 [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
770 [READING_POLICY] = POLICY_CHECK
774 * ima_post_read_file - in memory collect/appraise/audit measurement
775 * @file: pointer to the file to be measured/appraised/audit
776 * @buf: pointer to in memory file contents
777 * @size: size of in memory file contents
778 * @read_id: caller identifier
780 * Measure/appraise/audit in memory file based on policy. Policy rules
781 * are written in terms of a policy identifier.
783 * On success return 0. On integrity appraisal error, assuming the file
784 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
786 int ima_post_read_file(struct file *file, void *buf, loff_t size,
787 enum kernel_read_file_id read_id)
792 /* permit signed certs */
793 if (!file && read_id == READING_X509_CERTIFICATE)
796 if (!file || !buf || size == 0) { /* should never happen */
797 if (ima_appraise & IMA_APPRAISE_ENFORCE)
802 func = read_idmap[read_id] ?: FILE_CHECK;
803 security_current_getsecid_subj(&secid);
804 return process_measurement(file, current_cred(), secid, buf, size,
809 * ima_load_data - appraise decision based on policy
810 * @id: kernel load data caller identifier
811 * @contents: whether the full contents will be available in a later
812 * call to ima_post_load_data().
814 * Callers of this LSM hook can not measure, appraise, or audit the
815 * data provided by userspace. Enforce policy rules requiring a file
816 * signature (eg. kexec'ed kernel image).
818 * For permission return 0, otherwise return -EACCES.
820 int ima_load_data(enum kernel_load_data_id id, bool contents)
822 bool ima_enforce, sig_enforce;
825 (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
828 case LOADING_KEXEC_IMAGE:
829 if (IS_ENABLED(CONFIG_KEXEC_SIG)
830 && arch_ima_get_secureboot()) {
831 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
835 if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) {
836 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
837 return -EACCES; /* INTEGRITY_UNKNOWN */
840 case LOADING_FIRMWARE:
841 if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {
842 pr_err("Prevent firmware sysfs fallback loading.\n");
843 return -EACCES; /* INTEGRITY_UNKNOWN */
847 sig_enforce = is_module_sig_enforced();
849 if (ima_enforce && (!sig_enforce
850 && (ima_appraise & IMA_APPRAISE_MODULES))) {
851 pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
852 return -EACCES; /* INTEGRITY_UNKNOWN */
862 * ima_post_load_data - appraise decision based on policy
863 * @buf: pointer to in memory file contents
864 * @size: size of in memory file contents
865 * @load_id: kernel load data caller identifier
866 * @description: @load_id-specific description of contents
868 * Measure/appraise/audit in memory buffer based on policy. Policy rules
869 * are written in terms of a policy identifier.
871 * On success return 0. On integrity appraisal error, assuming the file
872 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
874 int ima_post_load_data(char *buf, loff_t size,
875 enum kernel_load_data_id load_id,
878 if (load_id == LOADING_FIRMWARE) {
879 if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
880 (ima_appraise & IMA_APPRAISE_ENFORCE)) {
881 pr_err("Prevent firmware loading_store.\n");
882 return -EACCES; /* INTEGRITY_UNKNOWN */
891 * process_buffer_measurement - Measure the buffer or the buffer data hash
892 * @idmap: idmap of the mount the inode was found from
893 * @inode: inode associated with the object being measured (NULL for KEY_CHECK)
894 * @buf: pointer to the buffer that needs to be added to the log.
895 * @size: size of buffer(in bytes).
896 * @eventname: event name to be used for the buffer entry.
898 * @pcr: pcr to extend the measurement
899 * @func_data: func specific data, may be NULL
900 * @buf_hash: measure buffer data hash
901 * @digest: buffer digest will be written to
902 * @digest_len: buffer length
904 * Based on policy, either the buffer data or buffer data hash is measured
906 * Return: 0 if the buffer has been successfully measured, 1 if the digest
907 * has been written to the passed location but not added to a measurement entry,
908 * a negative value otherwise.
910 int process_buffer_measurement(struct mnt_idmap *idmap,
911 struct inode *inode, const void *buf, int size,
912 const char *eventname, enum ima_hooks func,
913 int pcr, const char *func_data,
914 bool buf_hash, u8 *digest, size_t digest_len)
917 const char *audit_cause = "ENOMEM";
918 struct ima_template_entry *entry = NULL;
919 struct integrity_iint_cache iint = {};
920 struct ima_event_data event_data = {.iint = &iint,
921 .filename = eventname,
924 struct ima_template_desc *template;
925 struct ima_max_digest_data hash;
926 char digest_hash[IMA_MAX_DIGEST_SIZE];
927 int digest_hash_len = hash_digest_size[ima_hash_algo];
932 if (digest && digest_len < digest_hash_len)
935 if (!ima_policy_flag && !digest)
938 template = ima_template_desc_buf();
941 audit_cause = "ima_template_desc_buf";
946 * Both LSM hooks and auxilary based buffer measurements are
947 * based on policy. To avoid code duplication, differentiate
948 * between the LSM hooks and auxilary buffer measurements,
949 * retrieving the policy rule information only for the LSM hook
950 * buffer measurements.
953 security_current_getsecid_subj(&secid);
954 action = ima_get_action(idmap, inode, current_cred(),
955 secid, 0, func, &pcr, &template,
957 if (!(action & IMA_MEASURE) && !digest)
962 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
964 iint.ima_hash = &hash.hdr;
965 iint.ima_hash->algo = ima_hash_algo;
966 iint.ima_hash->length = hash_digest_size[ima_hash_algo];
968 ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
970 audit_cause = "hashing_error";
975 memcpy(digest_hash, hash.hdr.digest, digest_hash_len);
977 ret = ima_calc_buffer_hash(digest_hash, digest_hash_len,
980 audit_cause = "hashing_error";
984 event_data.buf = digest_hash;
985 event_data.buf_len = digest_hash_len;
989 memcpy(digest, iint.ima_hash->digest, digest_hash_len);
991 if (!ima_policy_flag || (func && !(action & IMA_MEASURE)))
994 ret = ima_alloc_init_template(&event_data, &entry, template);
996 audit_cause = "alloc_entry";
1000 ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr);
1002 audit_cause = "store_entry";
1003 ima_free_template_entry(entry);
1008 integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname,
1009 func_measure_str(func),
1010 audit_cause, ret, 0, ret);
1016 * ima_kexec_cmdline - measure kexec cmdline boot args
1017 * @kernel_fd: file descriptor of the kexec kernel being loaded
1018 * @buf: pointer to buffer
1019 * @size: size of buffer
1021 * Buffers can only be measured, not appraised.
1023 void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
1030 f = fdget(kernel_fd);
1034 process_buffer_measurement(file_mnt_idmap(f.file), file_inode(f.file),
1035 buf, size, "kexec-cmdline", KEXEC_CMDLINE, 0,
1036 NULL, false, NULL, 0);
1041 * ima_measure_critical_data - measure kernel integrity critical data
1042 * @event_label: unique event label for grouping and limiting critical data
1043 * @event_name: event name for the record in the IMA measurement list
1044 * @buf: pointer to buffer data
1045 * @buf_len: length of buffer data (in bytes)
1046 * @hash: measure buffer data hash
1047 * @digest: buffer digest will be written to
1048 * @digest_len: buffer length
1050 * Measure data critical to the integrity of the kernel into the IMA log
1051 * and extend the pcr. Examples of critical data could be various data
1052 * structures, policies, and states stored in kernel memory that can
1053 * impact the integrity of the system.
1055 * Return: 0 if the buffer has been successfully measured, 1 if the digest
1056 * has been written to the passed location but not added to a measurement entry,
1057 * a negative value otherwise.
1059 int ima_measure_critical_data(const char *event_label,
1060 const char *event_name,
1061 const void *buf, size_t buf_len,
1062 bool hash, u8 *digest, size_t digest_len)
1064 if (!event_name || !event_label || !buf || !buf_len)
1067 return process_buffer_measurement(&nop_mnt_idmap, NULL, buf, buf_len,
1068 event_name, CRITICAL_DATA, 0,
1069 event_label, hash, digest,
1072 EXPORT_SYMBOL_GPL(ima_measure_critical_data);
1074 static int __init init_ima(void)
1078 ima_appraise_parse_cmdline();
1079 ima_init_template_list();
1080 hash_setup(CONFIG_IMA_DEFAULT_HASH);
1083 if (error && strcmp(hash_algo_name[ima_hash_algo],
1084 CONFIG_IMA_DEFAULT_HASH) != 0) {
1085 pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
1086 hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
1087 hash_setup_done = 0;
1088 hash_setup(CONFIG_IMA_DEFAULT_HASH);
1095 error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
1097 pr_warn("Couldn't register LSM notifier, error %d\n", error);
1100 ima_update_policy_flags();
1105 late_initcall(init_ima); /* Start IMA after the TPM is available */