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 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 /* Prevent mmap'ing a file execute that is already mmap'ed write */
80 static int mmap_violation_check(enum ima_hooks func, struct file *file,
81 char **pathbuf, const char **pathname,
87 if ((func == MMAP_CHECK) && mapping_writably_mapped(file->f_mapping)) {
89 inode = file_inode(file);
91 if (!*pathbuf) /* ima_rdwr_violation possibly pre-fetched */
92 *pathname = ima_d_path(&file->f_path, pathbuf,
94 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname,
95 "mmap_file", "mmapped_writers", rc, 0);
101 * ima_rdwr_violation_check
103 * Only invalidate the PCR for measured files:
104 * - Opening a file for write when already open for read,
105 * results in a time of measure, time of use (ToMToU) error.
106 * - Opening a file for read when already open for write,
107 * could result in a file measurement error.
110 static void ima_rdwr_violation_check(struct file *file,
111 struct integrity_iint_cache *iint,
114 const char **pathname,
117 struct inode *inode = file_inode(file);
118 fmode_t mode = file->f_mode;
119 bool send_tomtou = false, send_writers = false;
121 if (mode & FMODE_WRITE) {
122 if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
124 iint = integrity_iint_find(inode);
125 /* IMA_MEASURE is set from reader side */
126 if (iint && test_bit(IMA_MUST_MEASURE,
127 &iint->atomic_flags))
132 set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
133 if (inode_is_open_for_write(inode) && must_measure)
137 if (!send_tomtou && !send_writers)
140 *pathname = ima_d_path(&file->f_path, pathbuf, filename);
143 ima_add_violation(file, *pathname, iint,
144 "invalid_pcr", "ToMToU");
146 ima_add_violation(file, *pathname, iint,
147 "invalid_pcr", "open_writers");
150 static void ima_check_last_writer(struct integrity_iint_cache *iint,
151 struct inode *inode, struct file *file)
153 fmode_t mode = file->f_mode;
156 if (!(mode & FMODE_WRITE))
159 mutex_lock(&iint->mutex);
160 if (atomic_read(&inode->i_writecount) == 1) {
161 update = test_and_clear_bit(IMA_UPDATE_XATTR,
162 &iint->atomic_flags);
163 if (!IS_I_VERSION(inode) ||
164 !inode_eq_iversion(inode, iint->version) ||
165 (iint->flags & IMA_NEW_FILE)) {
166 iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
167 iint->measured_pcrs = 0;
169 ima_update_xattr(iint, file);
172 mutex_unlock(&iint->mutex);
176 * ima_file_free - called on __fput()
177 * @file: pointer to file structure being freed
179 * Flag files that changed, based on i_version
181 void ima_file_free(struct file *file)
183 struct inode *inode = file_inode(file);
184 struct integrity_iint_cache *iint;
186 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
189 iint = integrity_iint_find(inode);
193 ima_check_last_writer(iint, inode, file);
196 static int process_measurement(struct file *file, const struct cred *cred,
197 u32 secid, char *buf, loff_t size, int mask,
200 struct inode *inode = file_inode(file);
201 struct integrity_iint_cache *iint = NULL;
202 struct ima_template_desc *template_desc = NULL;
203 char *pathbuf = NULL;
204 char filename[NAME_MAX];
205 const char *pathname = NULL;
206 int rc = 0, action, must_appraise = 0;
207 int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
208 struct evm_ima_xattr_data *xattr_value = NULL;
209 struct modsig *modsig = NULL;
211 bool violation_check;
212 enum hash_algo hash_algo;
214 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
217 /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
218 * bitmask based on the appraise/audit/measurement policy.
219 * Included is the appraise submask.
221 action = ima_get_action(file_mnt_user_ns(file), inode, cred, secid,
222 mask, func, &pcr, &template_desc, NULL);
223 violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
224 (ima_policy_flag & IMA_MEASURE));
225 if (!action && !violation_check)
228 must_appraise = action & IMA_APPRAISE;
230 /* Is the appraise rule hook specific? */
231 if (action & IMA_FILE_APPRAISE)
237 iint = integrity_inode_get(inode);
242 if (!rc && violation_check)
243 ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
244 &pathbuf, &pathname, filename);
253 mutex_lock(&iint->mutex);
255 if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
256 /* reset appraisal flags if ima_inode_post_setattr was called */
257 iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
258 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
262 * Re-evaulate the file if either the xattr has changed or the
263 * kernel has no way of detecting file change on the filesystem.
264 * (Limited to privileged mounted filesystems.)
266 if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) ||
267 ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
268 !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) &&
269 !(action & IMA_FAIL_UNVERIFIABLE_SIGS))) {
270 iint->flags &= ~IMA_DONE_MASK;
271 iint->measured_pcrs = 0;
274 /* Determine if already appraised/measured based on bitmask
275 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
276 * IMA_AUDIT, IMA_AUDITED)
278 iint->flags |= action;
279 action &= IMA_DO_MASK;
280 action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
282 /* If target pcr is already measured, unset IMA_MEASURE action */
283 if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
284 action ^= IMA_MEASURE;
286 /* HASH sets the digital signature and update flags, nothing else */
287 if ((action & IMA_HASH) &&
288 !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
289 xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
290 if ((xattr_value && xattr_len > 2) &&
291 (xattr_value->type == EVM_IMA_XATTR_DIGSIG))
292 set_bit(IMA_DIGSIG, &iint->atomic_flags);
293 iint->flags |= IMA_HASHED;
295 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
298 /* Nothing to do, just return existing appraised status */
301 rc = mmap_violation_check(func, file, &pathbuf,
302 &pathname, filename);
304 rc = ima_get_cache_status(iint, func);
309 if ((action & IMA_APPRAISE_SUBMASK) ||
310 strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
311 /* read 'security.ima' */
312 xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
315 * Read the appended modsig if allowed by the policy, and allow
316 * an additional measurement list entry, if needed, based on the
317 * template format and whether the file was already measured.
319 if (iint->flags & IMA_MODSIG_ALLOWED) {
320 rc = ima_read_modsig(func, buf, size, &modsig);
322 if (!rc && ima_template_has_modsig(template_desc) &&
323 iint->flags & IMA_MEASURED)
324 action |= IMA_MEASURE;
328 hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
330 rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
331 if (rc != 0 && rc != -EBADF && rc != -EINVAL)
334 if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */
335 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
337 if (action & IMA_MEASURE)
338 ima_store_measurement(iint, file, pathname,
339 xattr_value, xattr_len, modsig, pcr,
341 if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
342 rc = ima_check_blacklist(iint, modsig, pcr);
345 rc = ima_appraise_measurement(func, iint, file,
346 pathname, xattr_value,
351 rc = mmap_violation_check(func, file, &pathbuf,
352 &pathname, filename);
354 if (action & IMA_AUDIT)
355 ima_audit_measurement(iint, pathname);
357 if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
360 if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
361 !(iint->flags & IMA_NEW_FILE))
363 mutex_unlock(&iint->mutex);
365 ima_free_modsig(modsig);
370 if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
372 if (file->f_mode & FMODE_WRITE)
373 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
379 * ima_file_mmap - based on policy, collect/store measurement.
380 * @file: pointer to the file to be measured (May be NULL)
381 * @prot: contains the protection that will be applied by the kernel.
383 * Measure files being mmapped executable based on the ima_must_measure()
386 * On success return 0. On integrity appraisal error, assuming the file
387 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
389 int ima_file_mmap(struct file *file, unsigned long prot)
393 if (file && (prot & PROT_EXEC)) {
394 security_task_getsecid_subj(current, &secid);
395 return process_measurement(file, current_cred(), secid, NULL,
396 0, MAY_EXEC, MMAP_CHECK);
403 * ima_file_mprotect - based on policy, limit mprotect change
404 * @prot: contains the protection that will be applied by the kernel.
406 * Files can be mmap'ed read/write and later changed to execute to circumvent
407 * IMA's mmap appraisal policy rules. Due to locking issues (mmap semaphore
408 * would be taken before i_mutex), files can not be measured or appraised at
409 * this point. Eliminate this integrity gap by denying the mprotect
410 * PROT_EXECUTE change, if an mmap appraise policy rule exists.
412 * On mprotect change success, return 0. On failure, return -EACESS.
414 int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
416 struct ima_template_desc *template = NULL;
417 struct file *file = vma->vm_file;
418 char filename[NAME_MAX];
419 char *pathbuf = NULL;
420 const char *pathname = NULL;
427 /* Is mprotect making an mmap'ed file executable? */
428 if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
429 !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
432 security_task_getsecid_subj(current, &secid);
433 inode = file_inode(vma->vm_file);
434 action = ima_get_action(file_mnt_user_ns(vma->vm_file), inode,
435 current_cred(), secid, MAY_EXEC, MMAP_CHECK,
436 &pcr, &template, NULL);
438 /* Is the mmap'ed file in policy? */
439 if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
442 if (action & IMA_APPRAISE_SUBMASK)
446 pathname = ima_d_path(&file->f_path, &pathbuf, filename);
447 integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname,
448 "collect_data", "failed-mprotect", result, 0);
456 * ima_bprm_check - based on policy, collect/store measurement.
457 * @bprm: contains the linux_binprm structure
459 * The OS protects against an executable file, already open for write,
460 * from being executed in deny_write_access() and an executable file,
461 * already open for execute, from being modified in get_write_access().
462 * So we can be certain that what we verify and measure here is actually
463 * what is being executed.
465 * On success return 0. On integrity appraisal error, assuming the file
466 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
468 int ima_bprm_check(struct linux_binprm *bprm)
473 security_task_getsecid_subj(current, &secid);
474 ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
475 MAY_EXEC, BPRM_CHECK);
479 security_cred_getsecid(bprm->cred, &secid);
480 return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
481 MAY_EXEC, CREDS_CHECK);
485 * ima_file_check - based on policy, collect/store measurement.
486 * @file: pointer to the file to be measured
487 * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
489 * Measure files based on the ima_must_measure() policy decision.
491 * On success return 0. On integrity appraisal error, assuming the file
492 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
494 int ima_file_check(struct file *file, int mask)
498 security_task_getsecid_subj(current, &secid);
499 return process_measurement(file, current_cred(), secid, NULL, 0,
500 mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
501 MAY_APPEND), FILE_CHECK);
503 EXPORT_SYMBOL_GPL(ima_file_check);
505 static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
507 struct integrity_iint_cache *iint;
510 if (!ima_policy_flag)
513 iint = integrity_iint_find(inode);
517 mutex_lock(&iint->mutex);
520 * ima_file_hash can be called when ima_collect_measurement has still
521 * not been called, we might not always have a hash.
523 if (!iint->ima_hash) {
524 mutex_unlock(&iint->mutex);
531 copied_size = min_t(size_t, iint->ima_hash->length, buf_size);
532 memcpy(buf, iint->ima_hash->digest, copied_size);
534 hash_algo = iint->ima_hash->algo;
535 mutex_unlock(&iint->mutex);
541 * ima_file_hash - return the stored measurement if a file has been hashed and
542 * is in the iint cache.
543 * @file: pointer to the file
544 * @buf: buffer in which to store the hash
545 * @buf_size: length of the buffer
547 * On success, return the hash algorithm (as defined in the enum hash_algo).
548 * If buf is not NULL, this function also outputs the hash into buf.
549 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
550 * It generally just makes sense to pass a buffer capable of holding the largest
551 * possible hash: IMA_MAX_DIGEST_SIZE.
552 * The file hash returned is based on the entire file, including the appended
555 * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP.
556 * If the parameters are incorrect, return -EINVAL.
558 int ima_file_hash(struct file *file, char *buf, size_t buf_size)
563 return __ima_inode_hash(file_inode(file), buf, buf_size);
565 EXPORT_SYMBOL_GPL(ima_file_hash);
568 * ima_inode_hash - return the stored measurement if the inode has been hashed
569 * and is in the iint cache.
570 * @inode: pointer to the inode
571 * @buf: buffer in which to store the hash
572 * @buf_size: length of the buffer
574 * On success, return the hash algorithm (as defined in the enum hash_algo).
575 * If buf is not NULL, this function also outputs the hash into buf.
576 * If the hash is larger than buf_size, then only buf_size bytes will be copied.
577 * It generally just makes sense to pass a buffer capable of holding the largest
578 * possible hash: IMA_MAX_DIGEST_SIZE.
579 * The hash returned is based on the entire contents, including the appended
582 * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP.
583 * If the parameters are incorrect, return -EINVAL.
585 int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
590 return __ima_inode_hash(inode, buf, buf_size);
592 EXPORT_SYMBOL_GPL(ima_inode_hash);
595 * ima_post_create_tmpfile - mark newly created tmpfile as new
596 * @mnt_userns: user namespace of the mount the inode was found from
597 * @file : newly created tmpfile
599 * No measuring, appraising or auditing of newly created tmpfiles is needed.
600 * Skip calling process_measurement(), but indicate which newly, created
601 * tmpfiles are in policy.
603 void ima_post_create_tmpfile(struct user_namespace *mnt_userns,
606 struct integrity_iint_cache *iint;
609 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
612 must_appraise = ima_must_appraise(mnt_userns, inode, MAY_ACCESS,
617 /* Nothing to do if we can't allocate memory */
618 iint = integrity_inode_get(inode);
622 /* needed for writing the security xattrs */
623 set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
624 iint->ima_file_status = INTEGRITY_PASS;
628 * ima_post_path_mknod - mark as a new inode
629 * @mnt_userns: user namespace of the mount the inode was found from
630 * @dentry: newly created dentry
632 * Mark files created via the mknodat syscall as new, so that the
633 * file data can be written later.
635 void ima_post_path_mknod(struct user_namespace *mnt_userns,
636 struct dentry *dentry)
638 struct integrity_iint_cache *iint;
639 struct inode *inode = dentry->d_inode;
642 if (!ima_policy_flag || !S_ISREG(inode->i_mode))
645 must_appraise = ima_must_appraise(mnt_userns, inode, MAY_ACCESS,
650 /* Nothing to do if we can't allocate memory */
651 iint = integrity_inode_get(inode);
655 /* needed for re-opening empty files */
656 iint->flags |= IMA_NEW_FILE;
660 * ima_read_file - pre-measure/appraise hook decision based on policy
661 * @file: pointer to the file to be measured/appraised/audit
662 * @read_id: caller identifier
663 * @contents: whether a subsequent call will be made to ima_post_read_file()
665 * Permit reading a file based on policy. The policy rules are written
666 * in terms of the policy identifier. Appraising the integrity of
667 * a file requires a file descriptor.
669 * For permission return 0, otherwise return -EACCES.
671 int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
678 * Do devices using pre-allocated memory run the risk of the
679 * firmware being accessible to the device prior to the completion
680 * of IMA's signature verification any more than when using two
681 * buffers? It may be desirable to include the buffer address
682 * in this API and walk all the dma_map_single() mappings to check.
686 * There will be a call made to ima_post_read_file() with
687 * a filled buffer, so we don't need to perform an extra
693 /* Read entire file for all partial reads. */
694 func = read_idmap[read_id] ?: FILE_CHECK;
695 security_task_getsecid_subj(current, &secid);
696 return process_measurement(file, current_cred(), secid, NULL,
700 const int read_idmap[READING_MAX_ID] = {
701 [READING_FIRMWARE] = FIRMWARE_CHECK,
702 [READING_MODULE] = MODULE_CHECK,
703 [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
704 [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
705 [READING_POLICY] = POLICY_CHECK
709 * ima_post_read_file - in memory collect/appraise/audit measurement
710 * @file: pointer to the file to be measured/appraised/audit
711 * @buf: pointer to in memory file contents
712 * @size: size of in memory file contents
713 * @read_id: caller identifier
715 * Measure/appraise/audit in memory file based on policy. Policy rules
716 * are written in terms of a policy identifier.
718 * On success return 0. On integrity appraisal error, assuming the file
719 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
721 int ima_post_read_file(struct file *file, void *buf, loff_t size,
722 enum kernel_read_file_id read_id)
727 /* permit signed certs */
728 if (!file && read_id == READING_X509_CERTIFICATE)
731 if (!file || !buf || size == 0) { /* should never happen */
732 if (ima_appraise & IMA_APPRAISE_ENFORCE)
737 func = read_idmap[read_id] ?: FILE_CHECK;
738 security_task_getsecid_subj(current, &secid);
739 return process_measurement(file, current_cred(), secid, buf, size,
744 * ima_load_data - appraise decision based on policy
745 * @id: kernel load data caller identifier
746 * @contents: whether the full contents will be available in a later
747 * call to ima_post_load_data().
749 * Callers of this LSM hook can not measure, appraise, or audit the
750 * data provided by userspace. Enforce policy rules requring a file
751 * signature (eg. kexec'ed kernel image).
753 * For permission return 0, otherwise return -EACCES.
755 int ima_load_data(enum kernel_load_data_id id, bool contents)
757 bool ima_enforce, sig_enforce;
760 (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
763 case LOADING_KEXEC_IMAGE:
764 if (IS_ENABLED(CONFIG_KEXEC_SIG)
765 && arch_ima_get_secureboot()) {
766 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
770 if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) {
771 pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
772 return -EACCES; /* INTEGRITY_UNKNOWN */
775 case LOADING_FIRMWARE:
776 if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {
777 pr_err("Prevent firmware sysfs fallback loading.\n");
778 return -EACCES; /* INTEGRITY_UNKNOWN */
782 sig_enforce = is_module_sig_enforced();
784 if (ima_enforce && (!sig_enforce
785 && (ima_appraise & IMA_APPRAISE_MODULES))) {
786 pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
787 return -EACCES; /* INTEGRITY_UNKNOWN */
797 * ima_post_load_data - appraise decision based on policy
798 * @buf: pointer to in memory file contents
799 * @size: size of in memory file contents
800 * @id: kernel load data caller identifier
801 * @description: @id-specific description of contents
803 * Measure/appraise/audit in memory buffer based on policy. Policy rules
804 * are written in terms of a policy identifier.
806 * On success return 0. On integrity appraisal error, assuming the file
807 * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
809 int ima_post_load_data(char *buf, loff_t size,
810 enum kernel_load_data_id load_id,
813 if (load_id == LOADING_FIRMWARE) {
814 if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
815 (ima_appraise & IMA_APPRAISE_ENFORCE)) {
816 pr_err("Prevent firmware loading_store.\n");
817 return -EACCES; /* INTEGRITY_UNKNOWN */
826 * process_buffer_measurement - Measure the buffer or the buffer data hash
827 * @mnt_userns: user namespace of the mount the inode was found from
828 * @inode: inode associated with the object being measured (NULL for KEY_CHECK)
829 * @buf: pointer to the buffer that needs to be added to the log.
830 * @size: size of buffer(in bytes).
831 * @eventname: event name to be used for the buffer entry.
833 * @pcr: pcr to extend the measurement
834 * @func_data: func specific data, may be NULL
835 * @buf_hash: measure buffer data hash
837 * Based on policy, either the buffer data or buffer data hash is measured
839 void process_buffer_measurement(struct user_namespace *mnt_userns,
840 struct inode *inode, const void *buf, int size,
841 const char *eventname, enum ima_hooks func,
842 int pcr, const char *func_data,
846 const char *audit_cause = "ENOMEM";
847 struct ima_template_entry *entry = NULL;
848 struct integrity_iint_cache iint = {};
849 struct ima_event_data event_data = {.iint = &iint,
850 .filename = eventname,
853 struct ima_template_desc *template;
855 struct ima_digest_data hdr;
856 char digest[IMA_MAX_DIGEST_SIZE];
858 char digest_hash[IMA_MAX_DIGEST_SIZE];
859 int digest_hash_len = hash_digest_size[ima_hash_algo];
864 if (!ima_policy_flag)
867 template = ima_template_desc_buf();
870 audit_cause = "ima_template_desc_buf";
875 * Both LSM hooks and auxilary based buffer measurements are
876 * based on policy. To avoid code duplication, differentiate
877 * between the LSM hooks and auxilary buffer measurements,
878 * retrieving the policy rule information only for the LSM hook
879 * buffer measurements.
882 security_task_getsecid_subj(current, &secid);
883 action = ima_get_action(mnt_userns, inode, current_cred(),
884 secid, 0, func, &pcr, &template,
886 if (!(action & IMA_MEASURE))
891 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
893 iint.ima_hash = &hash.hdr;
894 iint.ima_hash->algo = ima_hash_algo;
895 iint.ima_hash->length = hash_digest_size[ima_hash_algo];
897 ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
899 audit_cause = "hashing_error";
904 memcpy(digest_hash, hash.hdr.digest, digest_hash_len);
906 ret = ima_calc_buffer_hash(digest_hash, digest_hash_len,
909 audit_cause = "hashing_error";
913 event_data.buf = digest_hash;
914 event_data.buf_len = digest_hash_len;
917 ret = ima_alloc_init_template(&event_data, &entry, template);
919 audit_cause = "alloc_entry";
923 ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr);
925 audit_cause = "store_entry";
926 ima_free_template_entry(entry);
931 integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname,
932 func_measure_str(func),
933 audit_cause, ret, 0, ret);
939 * ima_kexec_cmdline - measure kexec cmdline boot args
940 * @kernel_fd: file descriptor of the kexec kernel being loaded
941 * @buf: pointer to buffer
942 * @size: size of buffer
944 * Buffers can only be measured, not appraised.
946 void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
953 f = fdget(kernel_fd);
957 process_buffer_measurement(file_mnt_user_ns(f.file), file_inode(f.file),
958 buf, size, "kexec-cmdline", KEXEC_CMDLINE, 0,
964 * ima_measure_critical_data - measure kernel integrity critical data
965 * @event_label: unique event label for grouping and limiting critical data
966 * @event_name: event name for the record in the IMA measurement list
967 * @buf: pointer to buffer data
968 * @buf_len: length of buffer data (in bytes)
969 * @hash: measure buffer data hash
971 * Measure data critical to the integrity of the kernel into the IMA log
972 * and extend the pcr. Examples of critical data could be various data
973 * structures, policies, and states stored in kernel memory that can
974 * impact the integrity of the system.
976 void ima_measure_critical_data(const char *event_label,
977 const char *event_name,
978 const void *buf, size_t buf_len,
981 if (!event_name || !event_label || !buf || !buf_len)
984 process_buffer_measurement(&init_user_ns, NULL, buf, buf_len, event_name,
985 CRITICAL_DATA, 0, event_label,
988 EXPORT_SYMBOL_GPL(ima_measure_critical_data);
990 static int __init init_ima(void)
994 ima_appraise_parse_cmdline();
995 ima_init_template_list();
996 hash_setup(CONFIG_IMA_DEFAULT_HASH);
999 if (error && strcmp(hash_algo_name[ima_hash_algo],
1000 CONFIG_IMA_DEFAULT_HASH) != 0) {
1001 pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
1002 hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
1003 hash_setup_done = 0;
1004 hash_setup(CONFIG_IMA_DEFAULT_HASH);
1011 error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
1013 pr_warn("Couldn't register LSM notifier, error %d\n", error);
1016 ima_update_policy_flag();
1021 late_initcall(init_ima); /* Start IMA after the TPM is available */