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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/module.h>
21 #include <linux/file.h>
22 #include <linux/binfmts.h>
23 #include <linux/mount.h>
24 #include <linux/mman.h>
25 #include <linux/slab.h>
26 #include <linux/xattr.h>
27 #include <linux/ima.h>
28 #include <linux/iversion.h>
29 #include <linux/fs.h>
30 
31 #include "ima.h"
32 
33 #ifdef CONFIG_IMA_APPRAISE
34 int ima_appraise = IMA_APPRAISE_ENFORCE;
35 #else
36 int ima_appraise;
37 #endif
38 
39 int ima_hash_algo = HASH_ALGO_SHA1;
40 static int hash_setup_done;
41 
42 static struct notifier_block ima_lsm_policy_notifier = {
43 	.notifier_call = ima_lsm_policy_change,
44 };
45 
46 static int __init hash_setup(char *str)
47 {
48 	struct ima_template_desc *template_desc = ima_template_desc_current();
49 	int i;
50 
51 	if (hash_setup_done)
52 		return 1;
53 
54 	if (strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0) {
55 		if (strncmp(str, "sha1", 4) == 0)
56 			ima_hash_algo = HASH_ALGO_SHA1;
57 		else if (strncmp(str, "md5", 3) == 0)
58 			ima_hash_algo = HASH_ALGO_MD5;
59 		else
60 			return 1;
61 		goto out;
62 	}
63 
64 	i = match_string(hash_algo_name, HASH_ALGO__LAST, str);
65 	if (i < 0)
66 		return 1;
67 
68 	ima_hash_algo = i;
69 out:
70 	hash_setup_done = 1;
71 	return 1;
72 }
73 __setup("ima_hash=", hash_setup);
74 
75 /* Prevent mmap'ing a file execute that is already mmap'ed write */
76 static int mmap_violation_check(enum ima_hooks func, struct file *file,
77 				char **pathbuf, const char **pathname,
78 				char *filename)
79 {
80 	struct inode *inode;
81 	int rc = 0;
82 
83 	if ((func == MMAP_CHECK) && mapping_writably_mapped(file->f_mapping)) {
84 		rc = -ETXTBSY;
85 		inode = file_inode(file);
86 
87 		if (!*pathbuf)	/* ima_rdwr_violation possibly pre-fetched */
88 			*pathname = ima_d_path(&file->f_path, pathbuf,
89 					       filename);
90 		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, *pathname,
91 				    "mmap_file", "mmapped_writers", rc, 0);
92 	}
93 	return rc;
94 }
95 
96 /*
97  * ima_rdwr_violation_check
98  *
99  * Only invalidate the PCR for measured files:
100  *	- Opening a file for write when already open for read,
101  *	  results in a time of measure, time of use (ToMToU) error.
102  *	- Opening a file for read when already open for write,
103  *	  could result in a file measurement error.
104  *
105  */
106 static void ima_rdwr_violation_check(struct file *file,
107 				     struct integrity_iint_cache *iint,
108 				     int must_measure,
109 				     char **pathbuf,
110 				     const char **pathname,
111 				     char *filename)
112 {
113 	struct inode *inode = file_inode(file);
114 	fmode_t mode = file->f_mode;
115 	bool send_tomtou = false, send_writers = false;
116 
117 	if (mode & FMODE_WRITE) {
118 		if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) {
119 			if (!iint)
120 				iint = integrity_iint_find(inode);
121 			/* IMA_MEASURE is set from reader side */
122 			if (iint && test_bit(IMA_MUST_MEASURE,
123 						&iint->atomic_flags))
124 				send_tomtou = true;
125 		}
126 	} else {
127 		if (must_measure)
128 			set_bit(IMA_MUST_MEASURE, &iint->atomic_flags);
129 		if (inode_is_open_for_write(inode) && must_measure)
130 			send_writers = true;
131 	}
132 
133 	if (!send_tomtou && !send_writers)
134 		return;
135 
136 	*pathname = ima_d_path(&file->f_path, pathbuf, filename);
137 
138 	if (send_tomtou)
139 		ima_add_violation(file, *pathname, iint,
140 				  "invalid_pcr", "ToMToU");
141 	if (send_writers)
142 		ima_add_violation(file, *pathname, iint,
143 				  "invalid_pcr", "open_writers");
144 }
145 
146 static void ima_check_last_writer(struct integrity_iint_cache *iint,
147 				  struct inode *inode, struct file *file)
148 {
149 	fmode_t mode = file->f_mode;
150 	bool update;
151 
152 	if (!(mode & FMODE_WRITE))
153 		return;
154 
155 	mutex_lock(&iint->mutex);
156 	if (atomic_read(&inode->i_writecount) == 1) {
157 		update = test_and_clear_bit(IMA_UPDATE_XATTR,
158 					    &iint->atomic_flags);
159 		if (!IS_I_VERSION(inode) ||
160 		    !inode_eq_iversion(inode, iint->version) ||
161 		    (iint->flags & IMA_NEW_FILE)) {
162 			iint->flags &= ~(IMA_DONE_MASK | IMA_NEW_FILE);
163 			iint->measured_pcrs = 0;
164 			if (update)
165 				ima_update_xattr(iint, file);
166 		}
167 	}
168 	mutex_unlock(&iint->mutex);
169 }
170 
171 /**
172  * ima_file_free - called on __fput()
173  * @file: pointer to file structure being freed
174  *
175  * Flag files that changed, based on i_version
176  */
177 void ima_file_free(struct file *file)
178 {
179 	struct inode *inode = file_inode(file);
180 	struct integrity_iint_cache *iint;
181 
182 	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
183 		return;
184 
185 	iint = integrity_iint_find(inode);
186 	if (!iint)
187 		return;
188 
189 	ima_check_last_writer(iint, inode, file);
190 }
191 
192 static int process_measurement(struct file *file, const struct cred *cred,
193 			       u32 secid, char *buf, loff_t size, int mask,
194 			       enum ima_hooks func)
195 {
196 	struct inode *inode = file_inode(file);
197 	struct integrity_iint_cache *iint = NULL;
198 	struct ima_template_desc *template_desc = NULL;
199 	char *pathbuf = NULL;
200 	char filename[NAME_MAX];
201 	const char *pathname = NULL;
202 	int rc = 0, action, must_appraise = 0;
203 	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
204 	struct evm_ima_xattr_data *xattr_value = NULL;
205 	struct modsig *modsig = NULL;
206 	int xattr_len = 0;
207 	bool violation_check;
208 	enum hash_algo hash_algo;
209 
210 	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
211 		return 0;
212 
213 	/* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
214 	 * bitmask based on the appraise/audit/measurement policy.
215 	 * Included is the appraise submask.
216 	 */
217 	action = ima_get_action(inode, cred, secid, mask, func, &pcr,
218 				&template_desc);
219 	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
220 			   (ima_policy_flag & IMA_MEASURE));
221 	if (!action && !violation_check)
222 		return 0;
223 
224 	must_appraise = action & IMA_APPRAISE;
225 
226 	/*  Is the appraise rule hook specific?  */
227 	if (action & IMA_FILE_APPRAISE)
228 		func = FILE_CHECK;
229 
230 	inode_lock(inode);
231 
232 	if (action) {
233 		iint = integrity_inode_get(inode);
234 		if (!iint)
235 			rc = -ENOMEM;
236 	}
237 
238 	if (!rc && violation_check)
239 		ima_rdwr_violation_check(file, iint, action & IMA_MEASURE,
240 					 &pathbuf, &pathname, filename);
241 
242 	inode_unlock(inode);
243 
244 	if (rc)
245 		goto out;
246 	if (!action)
247 		goto out;
248 
249 	mutex_lock(&iint->mutex);
250 
251 	if (test_and_clear_bit(IMA_CHANGE_ATTR, &iint->atomic_flags))
252 		/* reset appraisal flags if ima_inode_post_setattr was called */
253 		iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
254 				 IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
255 				 IMA_ACTION_FLAGS);
256 
257 	/*
258 	 * Re-evaulate the file if either the xattr has changed or the
259 	 * kernel has no way of detecting file change on the filesystem.
260 	 * (Limited to privileged mounted filesystems.)
261 	 */
262 	if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) ||
263 	    ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) &&
264 	     !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER) &&
265 	     !(action & IMA_FAIL_UNVERIFIABLE_SIGS))) {
266 		iint->flags &= ~IMA_DONE_MASK;
267 		iint->measured_pcrs = 0;
268 	}
269 
270 	/* Determine if already appraised/measured based on bitmask
271 	 * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
272 	 *  IMA_AUDIT, IMA_AUDITED)
273 	 */
274 	iint->flags |= action;
275 	action &= IMA_DO_MASK;
276 	action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
277 
278 	/* If target pcr is already measured, unset IMA_MEASURE action */
279 	if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
280 		action ^= IMA_MEASURE;
281 
282 	/* HASH sets the digital signature and update flags, nothing else */
283 	if ((action & IMA_HASH) &&
284 	    !(test_bit(IMA_DIGSIG, &iint->atomic_flags))) {
285 		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
286 		if ((xattr_value && xattr_len > 2) &&
287 		    (xattr_value->type == EVM_IMA_XATTR_DIGSIG))
288 			set_bit(IMA_DIGSIG, &iint->atomic_flags);
289 		iint->flags |= IMA_HASHED;
290 		action ^= IMA_HASH;
291 		set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
292 	}
293 
294 	/* Nothing to do, just return existing appraised status */
295 	if (!action) {
296 		if (must_appraise) {
297 			rc = mmap_violation_check(func, file, &pathbuf,
298 						  &pathname, filename);
299 			if (!rc)
300 				rc = ima_get_cache_status(iint, func);
301 		}
302 		goto out_locked;
303 	}
304 
305 	if ((action & IMA_APPRAISE_SUBMASK) ||
306 	    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
307 		/* read 'security.ima' */
308 		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
309 
310 		/*
311 		 * Read the appended modsig if allowed by the policy, and allow
312 		 * an additional measurement list entry, if needed, based on the
313 		 * template format and whether the file was already measured.
314 		 */
315 		if (iint->flags & IMA_MODSIG_ALLOWED) {
316 			rc = ima_read_modsig(func, buf, size, &modsig);
317 
318 			if (!rc && ima_template_has_modsig(template_desc) &&
319 			    iint->flags & IMA_MEASURED)
320 				action |= IMA_MEASURE;
321 		}
322 	}
323 
324 	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
325 
326 	rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
327 	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
328 		goto out_locked;
329 
330 	if (!pathbuf)	/* ima_rdwr_violation possibly pre-fetched */
331 		pathname = ima_d_path(&file->f_path, &pathbuf, filename);
332 
333 	if (action & IMA_MEASURE)
334 		ima_store_measurement(iint, file, pathname,
335 				      xattr_value, xattr_len, modsig, pcr,
336 				      template_desc);
337 	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
338 		inode_lock(inode);
339 		rc = ima_appraise_measurement(func, iint, file, pathname,
340 					      xattr_value, xattr_len, modsig);
341 		inode_unlock(inode);
342 		if (!rc)
343 			rc = mmap_violation_check(func, file, &pathbuf,
344 						  &pathname, filename);
345 	}
346 	if (action & IMA_AUDIT)
347 		ima_audit_measurement(iint, pathname);
348 
349 	if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO))
350 		rc = 0;
351 out_locked:
352 	if ((mask & MAY_WRITE) && test_bit(IMA_DIGSIG, &iint->atomic_flags) &&
353 	     !(iint->flags & IMA_NEW_FILE))
354 		rc = -EACCES;
355 	mutex_unlock(&iint->mutex);
356 	kfree(xattr_value);
357 	ima_free_modsig(modsig);
358 out:
359 	if (pathbuf)
360 		__putname(pathbuf);
361 	if (must_appraise) {
362 		if (rc && (ima_appraise & IMA_APPRAISE_ENFORCE))
363 			return -EACCES;
364 		if (file->f_mode & FMODE_WRITE)
365 			set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
366 	}
367 	return 0;
368 }
369 
370 /**
371  * ima_file_mmap - based on policy, collect/store measurement.
372  * @file: pointer to the file to be measured (May be NULL)
373  * @prot: contains the protection that will be applied by the kernel.
374  *
375  * Measure files being mmapped executable based on the ima_must_measure()
376  * policy decision.
377  *
378  * On success return 0.  On integrity appraisal error, assuming the file
379  * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
380  */
381 int ima_file_mmap(struct file *file, unsigned long prot)
382 {
383 	u32 secid;
384 
385 	if (file && (prot & PROT_EXEC)) {
386 		security_task_getsecid(current, &secid);
387 		return process_measurement(file, current_cred(), secid, NULL,
388 					   0, MAY_EXEC, MMAP_CHECK);
389 	}
390 
391 	return 0;
392 }
393 
394 /**
395  * ima_bprm_check - based on policy, collect/store measurement.
396  * @bprm: contains the linux_binprm structure
397  *
398  * The OS protects against an executable file, already open for write,
399  * from being executed in deny_write_access() and an executable file,
400  * already open for execute, from being modified in get_write_access().
401  * So we can be certain that what we verify and measure here is actually
402  * what is being executed.
403  *
404  * On success return 0.  On integrity appraisal error, assuming the file
405  * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
406  */
407 int ima_bprm_check(struct linux_binprm *bprm)
408 {
409 	int ret;
410 	u32 secid;
411 
412 	security_task_getsecid(current, &secid);
413 	ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
414 				  MAY_EXEC, BPRM_CHECK);
415 	if (ret)
416 		return ret;
417 
418 	security_cred_getsecid(bprm->cred, &secid);
419 	return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
420 				   MAY_EXEC, CREDS_CHECK);
421 }
422 
423 /**
424  * ima_path_check - based on policy, collect/store measurement.
425  * @file: pointer to the file to be measured
426  * @mask: contains MAY_READ, MAY_WRITE, MAY_EXEC or MAY_APPEND
427  *
428  * Measure files based on the ima_must_measure() policy decision.
429  *
430  * On success return 0.  On integrity appraisal error, assuming the file
431  * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
432  */
433 int ima_file_check(struct file *file, int mask)
434 {
435 	u32 secid;
436 
437 	security_task_getsecid(current, &secid);
438 	return process_measurement(file, current_cred(), secid, NULL, 0,
439 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
440 					   MAY_APPEND), FILE_CHECK);
441 }
442 EXPORT_SYMBOL_GPL(ima_file_check);
443 
444 /**
445  * ima_post_create_tmpfile - mark newly created tmpfile as new
446  * @file : newly created tmpfile
447  *
448  * No measuring, appraising or auditing of newly created tmpfiles is needed.
449  * Skip calling process_measurement(), but indicate which newly, created
450  * tmpfiles are in policy.
451  */
452 void ima_post_create_tmpfile(struct inode *inode)
453 {
454 	struct integrity_iint_cache *iint;
455 	int must_appraise;
456 
457 	must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
458 	if (!must_appraise)
459 		return;
460 
461 	/* Nothing to do if we can't allocate memory */
462 	iint = integrity_inode_get(inode);
463 	if (!iint)
464 		return;
465 
466 	/* needed for writing the security xattrs */
467 	set_bit(IMA_UPDATE_XATTR, &iint->atomic_flags);
468 	iint->ima_file_status = INTEGRITY_PASS;
469 }
470 
471 /**
472  * ima_post_path_mknod - mark as a new inode
473  * @dentry: newly created dentry
474  *
475  * Mark files created via the mknodat syscall as new, so that the
476  * file data can be written later.
477  */
478 void ima_post_path_mknod(struct dentry *dentry)
479 {
480 	struct integrity_iint_cache *iint;
481 	struct inode *inode = dentry->d_inode;
482 	int must_appraise;
483 
484 	must_appraise = ima_must_appraise(inode, MAY_ACCESS, FILE_CHECK);
485 	if (!must_appraise)
486 		return;
487 
488 	/* Nothing to do if we can't allocate memory */
489 	iint = integrity_inode_get(inode);
490 	if (!iint)
491 		return;
492 
493 	/* needed for re-opening empty files */
494 	iint->flags |= IMA_NEW_FILE;
495 }
496 
497 /**
498  * ima_read_file - pre-measure/appraise hook decision based on policy
499  * @file: pointer to the file to be measured/appraised/audit
500  * @read_id: caller identifier
501  *
502  * Permit reading a file based on policy. The policy rules are written
503  * in terms of the policy identifier.  Appraising the integrity of
504  * a file requires a file descriptor.
505  *
506  * For permission return 0, otherwise return -EACCES.
507  */
508 int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
509 {
510 	/*
511 	 * READING_FIRMWARE_PREALLOC_BUFFER
512 	 *
513 	 * Do devices using pre-allocated memory run the risk of the
514 	 * firmware being accessible to the device prior to the completion
515 	 * of IMA's signature verification any more than when using two
516 	 * buffers?
517 	 */
518 	return 0;
519 }
520 
521 const int read_idmap[READING_MAX_ID] = {
522 	[READING_FIRMWARE] = FIRMWARE_CHECK,
523 	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
524 	[READING_MODULE] = MODULE_CHECK,
525 	[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
526 	[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
527 	[READING_POLICY] = POLICY_CHECK
528 };
529 
530 /**
531  * ima_post_read_file - in memory collect/appraise/audit measurement
532  * @file: pointer to the file to be measured/appraised/audit
533  * @buf: pointer to in memory file contents
534  * @size: size of in memory file contents
535  * @read_id: caller identifier
536  *
537  * Measure/appraise/audit in memory file based on policy.  Policy rules
538  * are written in terms of a policy identifier.
539  *
540  * On success return 0.  On integrity appraisal error, assuming the file
541  * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
542  */
543 int ima_post_read_file(struct file *file, void *buf, loff_t size,
544 		       enum kernel_read_file_id read_id)
545 {
546 	enum ima_hooks func;
547 	u32 secid;
548 
549 	if (!file && read_id == READING_FIRMWARE) {
550 		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
551 		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
552 			pr_err("Prevent firmware loading_store.\n");
553 			return -EACCES;	/* INTEGRITY_UNKNOWN */
554 		}
555 		return 0;
556 	}
557 
558 	/* permit signed certs */
559 	if (!file && read_id == READING_X509_CERTIFICATE)
560 		return 0;
561 
562 	if (!file || !buf || size == 0) { /* should never happen */
563 		if (ima_appraise & IMA_APPRAISE_ENFORCE)
564 			return -EACCES;
565 		return 0;
566 	}
567 
568 	func = read_idmap[read_id] ?: FILE_CHECK;
569 	security_task_getsecid(current, &secid);
570 	return process_measurement(file, current_cred(), secid, buf, size,
571 				   MAY_READ, func);
572 }
573 
574 /**
575  * ima_load_data - appraise decision based on policy
576  * @id: kernel load data caller identifier
577  *
578  * Callers of this LSM hook can not measure, appraise, or audit the
579  * data provided by userspace.  Enforce policy rules requring a file
580  * signature (eg. kexec'ed kernel image).
581  *
582  * For permission return 0, otherwise return -EACCES.
583  */
584 int ima_load_data(enum kernel_load_data_id id)
585 {
586 	bool ima_enforce, sig_enforce;
587 
588 	ima_enforce =
589 		(ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE;
590 
591 	switch (id) {
592 	case LOADING_KEXEC_IMAGE:
593 		if (IS_ENABLED(CONFIG_KEXEC_SIG)
594 		    && arch_ima_get_secureboot()) {
595 			pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
596 			return -EACCES;
597 		}
598 
599 		if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) {
600 			pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
601 			return -EACCES;	/* INTEGRITY_UNKNOWN */
602 		}
603 		break;
604 	case LOADING_FIRMWARE:
605 		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) {
606 			pr_err("Prevent firmware sysfs fallback loading.\n");
607 			return -EACCES;	/* INTEGRITY_UNKNOWN */
608 		}
609 		break;
610 	case LOADING_MODULE:
611 		sig_enforce = is_module_sig_enforced();
612 
613 		if (ima_enforce && (!sig_enforce
614 				    && (ima_appraise & IMA_APPRAISE_MODULES))) {
615 			pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
616 			return -EACCES;	/* INTEGRITY_UNKNOWN */
617 		}
618 	default:
619 		break;
620 	}
621 	return 0;
622 }
623 
624 /*
625  * process_buffer_measurement - Measure the buffer to ima log.
626  * @buf: pointer to the buffer that needs to be added to the log.
627  * @size: size of buffer(in bytes).
628  * @eventname: event name to be used for the buffer entry.
629  * @cred: a pointer to a credentials structure for user validation.
630  * @secid: the secid of the task to be validated.
631  *
632  * Based on policy, the buffer is measured into the ima log.
633  */
634 static void process_buffer_measurement(const void *buf, int size,
635 				       const char *eventname,
636 				       const struct cred *cred, u32 secid)
637 {
638 	int ret = 0;
639 	struct ima_template_entry *entry = NULL;
640 	struct integrity_iint_cache iint = {};
641 	struct ima_event_data event_data = {.iint = &iint,
642 					    .filename = eventname,
643 					    .buf = buf,
644 					    .buf_len = size};
645 	struct ima_template_desc *template_desc = NULL;
646 	struct {
647 		struct ima_digest_data hdr;
648 		char digest[IMA_MAX_DIGEST_SIZE];
649 	} hash = {};
650 	int violation = 0;
651 	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
652 	int action = 0;
653 
654 	action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
655 				&template_desc);
656 	if (!(action & IMA_MEASURE))
657 		return;
658 
659 	iint.ima_hash = &hash.hdr;
660 	iint.ima_hash->algo = ima_hash_algo;
661 	iint.ima_hash->length = hash_digest_size[ima_hash_algo];
662 
663 	ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
664 	if (ret < 0)
665 		goto out;
666 
667 	ret = ima_alloc_init_template(&event_data, &entry, template_desc);
668 	if (ret < 0)
669 		goto out;
670 
671 	ret = ima_store_template(entry, violation, NULL, buf, pcr);
672 
673 	if (ret < 0)
674 		ima_free_template_entry(entry);
675 
676 out:
677 	return;
678 }
679 
680 /**
681  * ima_kexec_cmdline - measure kexec cmdline boot args
682  * @buf: pointer to buffer
683  * @size: size of buffer
684  *
685  * Buffers can only be measured, not appraised.
686  */
687 void ima_kexec_cmdline(const void *buf, int size)
688 {
689 	u32 secid;
690 
691 	if (buf && size != 0) {
692 		security_task_getsecid(current, &secid);
693 		process_buffer_measurement(buf, size, "kexec-cmdline",
694 					   current_cred(), secid);
695 	}
696 }
697 
698 static int __init init_ima(void)
699 {
700 	int error;
701 
702 	ima_init_template_list();
703 	hash_setup(CONFIG_IMA_DEFAULT_HASH);
704 	error = ima_init();
705 
706 	if (error && strcmp(hash_algo_name[ima_hash_algo],
707 			    CONFIG_IMA_DEFAULT_HASH) != 0) {
708 		pr_info("Allocating %s failed, going to use default hash algorithm %s\n",
709 			hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
710 		hash_setup_done = 0;
711 		hash_setup(CONFIG_IMA_DEFAULT_HASH);
712 		error = ima_init();
713 	}
714 
715 	error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
716 	if (error)
717 		pr_warn("Couldn't register LSM notifier, error %d\n", error);
718 
719 	if (!error)
720 		ima_update_policy_flag();
721 
722 	return error;
723 }
724 
725 late_initcall(init_ima);	/* Start IMA after the TPM is available */
726