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 struct ahash_completion {
31 struct completion completion;
35 /* minimum file size for ahash use */
36 static unsigned long ima_ahash_minsize;
37 module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
38 MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
40 /* default is 0 - 1 page. */
41 static int ima_maxorder;
42 static unsigned int ima_bufsize = PAGE_SIZE;
44 static int param_set_bufsize(const char *val, const struct kernel_param *kp)
46 unsigned long long size;
49 size = memparse(val, NULL);
50 order = get_order(size);
51 if (order >= MAX_ORDER)
54 ima_bufsize = PAGE_SIZE << order;
58 static const struct kernel_param_ops param_ops_bufsize = {
59 .set = param_set_bufsize,
60 .get = param_get_uint,
62 #define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
64 module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
65 MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
67 static struct crypto_shash *ima_shash_tfm;
68 static struct crypto_ahash *ima_ahash_tfm;
70 int __init ima_init_crypto(void)
74 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
75 if (IS_ERR(ima_shash_tfm)) {
76 rc = PTR_ERR(ima_shash_tfm);
77 pr_err("Can not allocate %s (reason: %ld)\n",
78 hash_algo_name[ima_hash_algo], rc);
81 pr_info("Allocated hash algorithm: %s\n",
82 hash_algo_name[ima_hash_algo]);
86 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
88 struct crypto_shash *tfm = ima_shash_tfm;
91 if (algo < 0 || algo >= HASH_ALGO__LAST)
94 if (algo != ima_hash_algo) {
95 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
98 pr_err("Can not allocate %s (reason: %d)\n",
99 hash_algo_name[algo], rc);
105 static void ima_free_tfm(struct crypto_shash *tfm)
107 if (tfm != ima_shash_tfm)
108 crypto_free_shash(tfm);
112 * ima_alloc_pages() - Allocate contiguous pages.
113 * @max_size: Maximum amount of memory to allocate.
114 * @allocated_size: Returned size of actual allocation.
115 * @last_warn: Should the min_size allocation warn or not.
117 * Tries to do opportunistic allocation for memory first trying to allocate
118 * max_size amount of memory and then splitting that until zero order is
119 * reached. Allocation is tried without generating allocation warnings unless
120 * last_warn is set. Last_warn set affects only last allocation of zero order.
122 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
124 * Return pointer to allocated memory, or NULL on failure.
126 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
130 int order = ima_maxorder;
131 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
134 order = min(get_order(max_size), order);
136 for (; order; order--) {
137 ptr = (void *)__get_free_pages(gfp_mask, order);
139 *allocated_size = PAGE_SIZE << order;
144 /* order is zero - one page */
146 gfp_mask = GFP_KERNEL;
149 gfp_mask |= __GFP_NOWARN;
151 ptr = (void *)__get_free_pages(gfp_mask, 0);
153 *allocated_size = PAGE_SIZE;
162 * ima_free_pages() - Free pages allocated by ima_alloc_pages().
163 * @ptr: Pointer to allocated pages.
164 * @size: Size of allocated buffer.
166 static void ima_free_pages(void *ptr, size_t size)
170 free_pages((unsigned long)ptr, get_order(size));
173 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
175 struct crypto_ahash *tfm = ima_ahash_tfm;
178 if (algo < 0 || algo >= HASH_ALGO__LAST)
179 algo = ima_hash_algo;
181 if (algo != ima_hash_algo || !tfm) {
182 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
184 if (algo == ima_hash_algo)
188 pr_err("Can not allocate %s (reason: %d)\n",
189 hash_algo_name[algo], rc);
195 static void ima_free_atfm(struct crypto_ahash *tfm)
197 if (tfm != ima_ahash_tfm)
198 crypto_free_ahash(tfm);
201 static void ahash_complete(struct crypto_async_request *req, int err)
203 struct ahash_completion *res = req->data;
205 if (err == -EINPROGRESS)
208 complete(&res->completion);
211 static int ahash_wait(int err, struct ahash_completion *res)
218 wait_for_completion(&res->completion);
219 reinit_completion(&res->completion);
223 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
229 static int ima_calc_file_hash_atfm(struct file *file,
230 struct ima_digest_data *hash,
231 struct crypto_ahash *tfm)
233 loff_t i_size, offset;
234 char *rbuf[2] = { NULL, };
235 int rc, rbuf_len, active = 0, ahash_rc = 0;
236 struct ahash_request *req;
237 struct scatterlist sg[1];
238 struct ahash_completion res;
241 hash->length = crypto_ahash_digestsize(tfm);
243 req = ahash_request_alloc(tfm, GFP_KERNEL);
247 init_completion(&res.completion);
248 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
249 CRYPTO_TFM_REQ_MAY_SLEEP,
250 ahash_complete, &res);
252 rc = ahash_wait(crypto_ahash_init(req), &res);
256 i_size = i_size_read(file_inode(file));
262 * Try to allocate maximum size of memory.
263 * Fail if even a single page cannot be allocated.
265 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
271 /* Only allocate one buffer if that is enough. */
272 if (i_size > rbuf_size[0]) {
274 * Try to allocate secondary buffer. If that fails fallback to
275 * using single buffering. Use previous memory allocation size
276 * as baseline for possible allocation size.
278 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
282 for (offset = 0; offset < i_size; offset += rbuf_len) {
283 if (!rbuf[1] && offset) {
284 /* Not using two buffers, and it is not the first
285 * read/request, wait for the completion of the
286 * previous ahash_update() request.
288 rc = ahash_wait(ahash_rc, &res);
293 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
294 rc = integrity_kernel_read(file, offset, rbuf[active],
296 if (rc != rbuf_len) {
302 if (rbuf[1] && offset) {
303 /* Using two buffers, and it is not the first
304 * read/request, wait for the completion of the
305 * previous ahash_update() request.
307 rc = ahash_wait(ahash_rc, &res);
312 sg_init_one(&sg[0], rbuf[active], rbuf_len);
313 ahash_request_set_crypt(req, sg, NULL, rbuf_len);
315 ahash_rc = crypto_ahash_update(req);
318 active = !active; /* swap buffers, if we use two */
320 /* wait for the last update request to complete */
321 rc = ahash_wait(ahash_rc, &res);
323 ima_free_pages(rbuf[0], rbuf_size[0]);
324 ima_free_pages(rbuf[1], rbuf_size[1]);
327 ahash_request_set_crypt(req, NULL, hash->digest, 0);
328 rc = ahash_wait(crypto_ahash_final(req), &res);
331 ahash_request_free(req);
335 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
337 struct crypto_ahash *tfm;
340 tfm = ima_alloc_atfm(hash->algo);
344 rc = ima_calc_file_hash_atfm(file, hash, tfm);
351 static int ima_calc_file_hash_tfm(struct file *file,
352 struct ima_digest_data *hash,
353 struct crypto_shash *tfm)
355 loff_t i_size, offset = 0;
358 SHASH_DESC_ON_STACK(shash, tfm);
363 hash->length = crypto_shash_digestsize(tfm);
365 rc = crypto_shash_init(shash);
369 i_size = i_size_read(file_inode(file));
374 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
378 while (offset < i_size) {
381 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
390 rc = crypto_shash_update(shash, rbuf, rbuf_len);
397 rc = crypto_shash_final(shash, hash->digest);
401 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
403 struct crypto_shash *tfm;
406 tfm = ima_alloc_tfm(hash->algo);
410 rc = ima_calc_file_hash_tfm(file, hash, tfm);
418 * ima_calc_file_hash - calculate file hash
420 * Asynchronous hash (ahash) allows using HW acceleration for calculating
421 * a hash. ahash performance varies for different data sizes on different
422 * crypto accelerators. shash performance might be better for smaller files.
423 * The 'ima.ahash_minsize' module parameter allows specifying the best
424 * minimum file size for using ahash on the system.
426 * If the ima.ahash_minsize parameter is not specified, this function uses
427 * shash for the hash calculation. If ahash fails, it falls back to using
430 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
434 struct file *f = file;
435 bool new_file_instance = false;
438 * For consistency, fail file's opened with the O_DIRECT flag on
439 * filesystems mounted with/without DAX option.
441 if (file->f_flags & O_DIRECT) {
442 hash->length = hash_digest_size[ima_hash_algo];
443 hash->algo = ima_hash_algo;
447 /* Open a new file instance in O_RDONLY if we cannot read */
448 if (!(file->f_mode & FMODE_READ)) {
449 int flags = file->f_flags & ~(O_WRONLY | O_APPEND |
450 O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL);
452 f = dentry_open(&file->f_path, flags, file->f_cred);
456 new_file_instance = true;
459 i_size = i_size_read(file_inode(f));
461 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
462 rc = ima_calc_file_ahash(f, hash);
467 rc = ima_calc_file_shash(f, hash);
469 if (new_file_instance)
475 * Calculate the hash of template data
477 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
478 struct ima_template_desc *td,
480 struct ima_digest_data *hash,
481 struct crypto_shash *tfm)
483 SHASH_DESC_ON_STACK(shash, tfm);
489 hash->length = crypto_shash_digestsize(tfm);
491 rc = crypto_shash_init(shash);
495 for (i = 0; i < num_fields; i++) {
496 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
497 u8 *data_to_hash = field_data[i].data;
498 u32 datalen = field_data[i].len;
499 u32 datalen_to_hash =
500 !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
502 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
503 rc = crypto_shash_update(shash,
504 (const u8 *) &datalen_to_hash,
505 sizeof(datalen_to_hash));
508 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
509 memcpy(buffer, data_to_hash, datalen);
510 data_to_hash = buffer;
511 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
513 rc = crypto_shash_update(shash, data_to_hash, datalen);
519 rc = crypto_shash_final(shash, hash->digest);
524 int ima_calc_field_array_hash(struct ima_field_data *field_data,
525 struct ima_template_desc *desc, int num_fields,
526 struct ima_digest_data *hash)
528 struct crypto_shash *tfm;
531 tfm = ima_alloc_tfm(hash->algo);
535 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
543 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
544 struct ima_digest_data *hash,
545 struct crypto_ahash *tfm)
547 struct ahash_request *req;
548 struct scatterlist sg;
549 struct ahash_completion res;
550 int rc, ahash_rc = 0;
552 hash->length = crypto_ahash_digestsize(tfm);
554 req = ahash_request_alloc(tfm, GFP_KERNEL);
558 init_completion(&res.completion);
559 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
560 CRYPTO_TFM_REQ_MAY_SLEEP,
561 ahash_complete, &res);
563 rc = ahash_wait(crypto_ahash_init(req), &res);
567 sg_init_one(&sg, buf, len);
568 ahash_request_set_crypt(req, &sg, NULL, len);
570 ahash_rc = crypto_ahash_update(req);
572 /* wait for the update request to complete */
573 rc = ahash_wait(ahash_rc, &res);
575 ahash_request_set_crypt(req, NULL, hash->digest, 0);
576 rc = ahash_wait(crypto_ahash_final(req), &res);
579 ahash_request_free(req);
583 static int calc_buffer_ahash(const void *buf, loff_t len,
584 struct ima_digest_data *hash)
586 struct crypto_ahash *tfm;
589 tfm = ima_alloc_atfm(hash->algo);
593 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
600 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
601 struct ima_digest_data *hash,
602 struct crypto_shash *tfm)
604 SHASH_DESC_ON_STACK(shash, tfm);
611 hash->length = crypto_shash_digestsize(tfm);
613 rc = crypto_shash_init(shash);
618 len = size < PAGE_SIZE ? size : PAGE_SIZE;
619 rc = crypto_shash_update(shash, buf, len);
627 rc = crypto_shash_final(shash, hash->digest);
631 static int calc_buffer_shash(const void *buf, loff_t len,
632 struct ima_digest_data *hash)
634 struct crypto_shash *tfm;
637 tfm = ima_alloc_tfm(hash->algo);
641 rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
647 int ima_calc_buffer_hash(const void *buf, loff_t len,
648 struct ima_digest_data *hash)
652 if (ima_ahash_minsize && len >= ima_ahash_minsize) {
653 rc = calc_buffer_ahash(buf, len, hash);
658 return calc_buffer_shash(buf, len, hash);
661 static void __init ima_pcrread(int idx, u8 *pcr)
666 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
667 pr_err("Error Communicating to TPM chip\n");
671 * Calculate the boot aggregate hash
673 static int __init ima_calc_boot_aggregate_tfm(char *digest,
674 struct crypto_shash *tfm)
676 u8 pcr_i[TPM_DIGEST_SIZE];
678 SHASH_DESC_ON_STACK(shash, tfm);
683 rc = crypto_shash_init(shash);
687 /* cumulative sha1 over tpm registers 0-7 */
688 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
689 ima_pcrread(i, pcr_i);
690 /* now accumulate with current aggregate */
691 rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
696 crypto_shash_final(shash, digest);
700 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
702 struct crypto_shash *tfm;
705 tfm = ima_alloc_tfm(hash->algo);
709 hash->length = crypto_shash_digestsize(tfm);
710 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);