2 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
6 * Kylene Hall <kjhall@us.ibm.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, version 2 of the License.
13 * Calculates md5/sha1 file hash, template hash, boot-aggreate hash
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/kernel.h>
19 #include <linux/moduleparam.h>
20 #include <linux/ratelimit.h>
21 #include <linux/file.h>
22 #include <linux/crypto.h>
23 #include <linux/scatterlist.h>
24 #include <linux/err.h>
25 #include <linux/slab.h>
26 #include <crypto/hash.h>
30 /* minimum file size for ahash use */
31 static unsigned long ima_ahash_minsize;
32 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
33 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
35 /* default is 0 - 1 page. */
36 static int ima_maxorder;
37 static unsigned int ima_bufsize = PAGE_SIZE;
39 static int param_set_bufsize(const char *val, const struct kernel_param *kp)
41 unsigned long long size;
44 size = memparse(val, NULL);
45 order = get_order(size);
46 if (order >= MAX_ORDER)
49 ima_bufsize = PAGE_SIZE << order;
53 static const struct kernel_param_ops param_ops_bufsize = {
54 .set = param_set_bufsize,
55 .get = param_get_uint,
57 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
59 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
60 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
62 static struct crypto_shash *ima_shash_tfm;
63 static struct crypto_ahash *ima_ahash_tfm;
65 int __init ima_init_crypto(void)
69 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
70 if (IS_ERR(ima_shash_tfm)) {
71 rc = PTR_ERR(ima_shash_tfm);
72 pr_err("Can not allocate %s (reason: %ld)\n",
73 hash_algo_name[ima_hash_algo], rc);
76 pr_info("Allocated hash algorithm: %s\n",
77 hash_algo_name[ima_hash_algo]);
81 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
83 struct crypto_shash *tfm = ima_shash_tfm;
86 if (algo < 0 || algo >= HASH_ALGO__LAST)
89 if (algo != ima_hash_algo) {
90 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
93 pr_err("Can not allocate %s (reason: %d)\n",
94 hash_algo_name[algo], rc);
100 static void ima_free_tfm(struct crypto_shash *tfm)
102 if (tfm != ima_shash_tfm)
103 crypto_free_shash(tfm);
107 * ima_alloc_pages() - Allocate contiguous pages.
108 * @max_size: Maximum amount of memory to allocate.
109 * @allocated_size: Returned size of actual allocation.
110 * @last_warn: Should the min_size allocation warn or not.
112 * Tries to do opportunistic allocation for memory first trying to allocate
113 * max_size amount of memory and then splitting that until zero order is
114 * reached. Allocation is tried without generating allocation warnings unless
115 * last_warn is set. Last_warn set affects only last allocation of zero order.
117 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
119 * Return pointer to allocated memory, or NULL on failure.
121 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
125 int order = ima_maxorder;
126 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
129 order = min(get_order(max_size), order);
131 for (; order; order--) {
132 ptr = (void *)__get_free_pages(gfp_mask, order);
134 *allocated_size = PAGE_SIZE << order;
139 /* order is zero - one page */
141 gfp_mask = GFP_KERNEL;
144 gfp_mask |= __GFP_NOWARN;
146 ptr = (void *)__get_free_pages(gfp_mask, 0);
148 *allocated_size = PAGE_SIZE;
157 * ima_free_pages() - Free pages allocated by ima_alloc_pages().
158 * @ptr: Pointer to allocated pages.
159 * @size: Size of allocated buffer.
161 static void ima_free_pages(void *ptr, size_t size)
165 free_pages((unsigned long)ptr, get_order(size));
168 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
170 struct crypto_ahash *tfm = ima_ahash_tfm;
173 if (algo < 0 || algo >= HASH_ALGO__LAST)
174 algo = ima_hash_algo;
176 if (algo != ima_hash_algo || !tfm) {
177 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
179 if (algo == ima_hash_algo)
183 pr_err("Can not allocate %s (reason: %d)\n",
184 hash_algo_name[algo], rc);
190 static void ima_free_atfm(struct crypto_ahash *tfm)
192 if (tfm != ima_ahash_tfm)
193 crypto_free_ahash(tfm);
196 static inline int ahash_wait(int err, struct crypto_wait *wait)
199 err = crypto_wait_req(err, wait);
202 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
207 static int ima_calc_file_hash_atfm(struct file *file,
208 struct ima_digest_data *hash,
209 struct crypto_ahash *tfm)
211 loff_t i_size, offset;
212 char *rbuf[2] = { NULL, };
213 int rc, rbuf_len, active = 0, ahash_rc = 0;
214 struct ahash_request *req;
215 struct scatterlist sg[1];
216 struct crypto_wait wait;
219 hash->length = crypto_ahash_digestsize(tfm);
221 req = ahash_request_alloc(tfm, GFP_KERNEL);
225 crypto_init_wait(&wait);
226 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
227 CRYPTO_TFM_REQ_MAY_SLEEP,
228 crypto_req_done, &wait);
230 rc = ahash_wait(crypto_ahash_init(req), &wait);
234 i_size = i_size_read(file_inode(file));
240 * Try to allocate maximum size of memory.
241 * Fail if even a single page cannot be allocated.
243 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
249 /* Only allocate one buffer if that is enough. */
250 if (i_size > rbuf_size[0]) {
252 * Try to allocate secondary buffer. If that fails fallback to
253 * using single buffering. Use previous memory allocation size
254 * as baseline for possible allocation size.
256 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
260 for (offset = 0; offset < i_size; offset += rbuf_len) {
261 if (!rbuf[1] && offset) {
262 /* Not using two buffers, and it is not the first
263 * read/request, wait for the completion of the
264 * previous ahash_update() request.
266 rc = ahash_wait(ahash_rc, &wait);
271 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
272 rc = integrity_kernel_read(file, offset, rbuf[active],
277 if (rbuf[1] && offset) {
278 /* Using two buffers, and it is not the first
279 * read/request, wait for the completion of the
280 * previous ahash_update() request.
282 rc = ahash_wait(ahash_rc, &wait);
287 sg_init_one(&sg[0], rbuf[active], rbuf_len);
288 ahash_request_set_crypt(req, sg, NULL, rbuf_len);
290 ahash_rc = crypto_ahash_update(req);
293 active = !active; /* swap buffers, if we use two */
295 /* wait for the last update request to complete */
296 rc = ahash_wait(ahash_rc, &wait);
298 ima_free_pages(rbuf[0], rbuf_size[0]);
299 ima_free_pages(rbuf[1], rbuf_size[1]);
302 ahash_request_set_crypt(req, NULL, hash->digest, 0);
303 rc = ahash_wait(crypto_ahash_final(req), &wait);
306 ahash_request_free(req);
310 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
312 struct crypto_ahash *tfm;
315 tfm = ima_alloc_atfm(hash->algo);
319 rc = ima_calc_file_hash_atfm(file, hash, tfm);
326 static int ima_calc_file_hash_tfm(struct file *file,
327 struct ima_digest_data *hash,
328 struct crypto_shash *tfm)
330 loff_t i_size, offset = 0;
333 SHASH_DESC_ON_STACK(shash, tfm);
337 hash->length = crypto_shash_digestsize(tfm);
339 rc = crypto_shash_init(shash);
343 i_size = i_size_read(file_inode(file));
348 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
352 while (offset < i_size) {
355 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
364 rc = crypto_shash_update(shash, rbuf, rbuf_len);
371 rc = crypto_shash_final(shash, hash->digest);
375 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
377 struct crypto_shash *tfm;
380 tfm = ima_alloc_tfm(hash->algo);
384 rc = ima_calc_file_hash_tfm(file, hash, tfm);
392 * ima_calc_file_hash - calculate file hash
394 * Asynchronous hash (ahash) allows using HW acceleration for calculating
395 * a hash. ahash performance varies for different data sizes on different
396 * crypto accelerators. shash performance might be better for smaller files.
397 * The 'ima.ahash_minsize' module parameter allows specifying the best
398 * minimum file size for using ahash on the system.
400 * If the ima.ahash_minsize parameter is not specified, this function uses
401 * shash for the hash calculation. If ahash fails, it falls back to using
404 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
408 struct file *f = file;
409 bool new_file_instance = false, modified_flags = false;
412 * For consistency, fail file's opened with the O_DIRECT flag on
413 * filesystems mounted with/without DAX option.
415 if (file->f_flags & O_DIRECT) {
416 hash->length = hash_digest_size[ima_hash_algo];
417 hash->algo = ima_hash_algo;
421 /* Open a new file instance in O_RDONLY if we cannot read */
422 if (!(file->f_mode & FMODE_READ)) {
423 int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
424 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
426 f = dentry_open(&file->f_path, flags, file->f_cred);
429 * Cannot open the file again, lets modify f_flags
430 * of original and continue
432 pr_info_ratelimited("Unable to reopen file for reading.\n");
434 f->f_flags |= FMODE_READ;
435 modified_flags = true;
437 new_file_instance = true;
441 i_size = i_size_read(file_inode(f));
443 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
444 rc = ima_calc_file_ahash(f, hash);
449 rc = ima_calc_file_shash(f, hash);
451 if (new_file_instance)
453 else if (modified_flags)
454 f->f_flags &= ~FMODE_READ;
459 * Calculate the hash of template data
461 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
462 struct ima_template_desc *td,
464 struct ima_digest_data *hash,
465 struct crypto_shash *tfm)
467 SHASH_DESC_ON_STACK(shash, tfm);
472 hash->length = crypto_shash_digestsize(tfm);
474 rc = crypto_shash_init(shash);
478 for (i = 0; i < num_fields; i++) {
479 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
480 u8 *data_to_hash = field_data[i].data;
481 u32 datalen = field_data[i].len;
482 u32 datalen_to_hash =
483 !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
485 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
486 rc = crypto_shash_update(shash,
487 (const u8 *) &datalen_to_hash,
488 sizeof(datalen_to_hash));
491 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
492 memcpy(buffer, data_to_hash, datalen);
493 data_to_hash = buffer;
494 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
496 rc = crypto_shash_update(shash, data_to_hash, datalen);
502 rc = crypto_shash_final(shash, hash->digest);
507 int ima_calc_field_array_hash(struct ima_field_data *field_data,
508 struct ima_template_desc *desc, int num_fields,
509 struct ima_digest_data *hash)
511 struct crypto_shash *tfm;
514 tfm = ima_alloc_tfm(hash->algo);
518 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
526 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
527 struct ima_digest_data *hash,
528 struct crypto_ahash *tfm)
530 struct ahash_request *req;
531 struct scatterlist sg;
532 struct crypto_wait wait;
533 int rc, ahash_rc = 0;
535 hash->length = crypto_ahash_digestsize(tfm);
537 req = ahash_request_alloc(tfm, GFP_KERNEL);
541 crypto_init_wait(&wait);
542 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
543 CRYPTO_TFM_REQ_MAY_SLEEP,
544 crypto_req_done, &wait);
546 rc = ahash_wait(crypto_ahash_init(req), &wait);
550 sg_init_one(&sg, buf, len);
551 ahash_request_set_crypt(req, &sg, NULL, len);
553 ahash_rc = crypto_ahash_update(req);
555 /* wait for the update request to complete */
556 rc = ahash_wait(ahash_rc, &wait);
558 ahash_request_set_crypt(req, NULL, hash->digest, 0);
559 rc = ahash_wait(crypto_ahash_final(req), &wait);
562 ahash_request_free(req);
566 static int calc_buffer_ahash(const void *buf, loff_t len,
567 struct ima_digest_data *hash)
569 struct crypto_ahash *tfm;
572 tfm = ima_alloc_atfm(hash->algo);
576 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
583 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
584 struct ima_digest_data *hash,
585 struct crypto_shash *tfm)
587 SHASH_DESC_ON_STACK(shash, tfm);
593 hash->length = crypto_shash_digestsize(tfm);
595 rc = crypto_shash_init(shash);
600 len = size < PAGE_SIZE ? size : PAGE_SIZE;
601 rc = crypto_shash_update(shash, buf, len);
609 rc = crypto_shash_final(shash, hash->digest);
613 static int calc_buffer_shash(const void *buf, loff_t len,
614 struct ima_digest_data *hash)
616 struct crypto_shash *tfm;
619 tfm = ima_alloc_tfm(hash->algo);
623 rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
629 int ima_calc_buffer_hash(const void *buf, loff_t len,
630 struct ima_digest_data *hash)
634 if (ima_ahash_minsize && len >= ima_ahash_minsize) {
635 rc = calc_buffer_ahash(buf, len, hash);
640 return calc_buffer_shash(buf, len, hash);
643 static void __init ima_pcrread(u32 idx, struct tpm_digest *d)
648 if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0)
649 pr_err("Error Communicating to TPM chip\n");
653 * Calculate the boot aggregate hash
655 static int __init ima_calc_boot_aggregate_tfm(char *digest,
656 struct crypto_shash *tfm)
658 struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} };
661 SHASH_DESC_ON_STACK(shash, tfm);
665 rc = crypto_shash_init(shash);
669 /* cumulative sha1 over tpm registers 0-7 */
670 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
672 /* now accumulate with current aggregate */
673 rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE);
676 crypto_shash_final(shash, digest);
680 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
682 struct crypto_shash *tfm;
685 tfm = ima_alloc_tfm(hash->algo);
689 hash->length = crypto_shash_digestsize(tfm);
690 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);