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);
84 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
86 struct crypto_shash *tfm = ima_shash_tfm;
89 if (algo < 0 || algo >= HASH_ALGO__LAST)
92 if (algo != ima_hash_algo) {
93 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
96 pr_err("Can not allocate %s (reason: %d)\n",
97 hash_algo_name[algo], rc);
103 static void ima_free_tfm(struct crypto_shash *tfm)
105 if (tfm != ima_shash_tfm)
106 crypto_free_shash(tfm);
110 * ima_alloc_pages() - Allocate contiguous pages.
111 * @max_size: Maximum amount of memory to allocate.
112 * @allocated_size: Returned size of actual allocation.
113 * @last_warn: Should the min_size allocation warn or not.
115 * Tries to do opportunistic allocation for memory first trying to allocate
116 * max_size amount of memory and then splitting that until zero order is
117 * reached. Allocation is tried without generating allocation warnings unless
118 * last_warn is set. Last_warn set affects only last allocation of zero order.
120 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
122 * Return pointer to allocated memory, or NULL on failure.
124 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
128 int order = ima_maxorder;
129 gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY;
132 order = min(get_order(max_size), order);
134 for (; order; order--) {
135 ptr = (void *)__get_free_pages(gfp_mask, order);
137 *allocated_size = PAGE_SIZE << order;
142 /* order is zero - one page */
144 gfp_mask = GFP_KERNEL;
147 gfp_mask |= __GFP_NOWARN;
149 ptr = (void *)__get_free_pages(gfp_mask, 0);
151 *allocated_size = PAGE_SIZE;
160 * ima_free_pages() - Free pages allocated by ima_alloc_pages().
161 * @ptr: Pointer to allocated pages.
162 * @size: Size of allocated buffer.
164 static void ima_free_pages(void *ptr, size_t size)
168 free_pages((unsigned long)ptr, get_order(size));
171 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
173 struct crypto_ahash *tfm = ima_ahash_tfm;
176 if (algo < 0 || algo >= HASH_ALGO__LAST)
177 algo = ima_hash_algo;
179 if (algo != ima_hash_algo || !tfm) {
180 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
182 if (algo == ima_hash_algo)
186 pr_err("Can not allocate %s (reason: %d)\n",
187 hash_algo_name[algo], rc);
193 static void ima_free_atfm(struct crypto_ahash *tfm)
195 if (tfm != ima_ahash_tfm)
196 crypto_free_ahash(tfm);
199 static void ahash_complete(struct crypto_async_request *req, int err)
201 struct ahash_completion *res = req->data;
203 if (err == -EINPROGRESS)
206 complete(&res->completion);
209 static int ahash_wait(int err, struct ahash_completion *res)
216 wait_for_completion(&res->completion);
217 reinit_completion(&res->completion);
221 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
227 static int ima_calc_file_hash_atfm(struct file *file,
228 struct ima_digest_data *hash,
229 struct crypto_ahash *tfm)
231 loff_t i_size, offset;
232 char *rbuf[2] = { NULL, };
233 int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0;
234 struct ahash_request *req;
235 struct scatterlist sg[1];
236 struct ahash_completion res;
239 hash->length = crypto_ahash_digestsize(tfm);
241 req = ahash_request_alloc(tfm, GFP_KERNEL);
245 init_completion(&res.completion);
246 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
247 CRYPTO_TFM_REQ_MAY_SLEEP,
248 ahash_complete, &res);
250 rc = ahash_wait(crypto_ahash_init(req), &res);
254 i_size = i_size_read(file_inode(file));
260 * Try to allocate maximum size of memory.
261 * Fail if even a single page cannot be allocated.
263 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
269 /* Only allocate one buffer if that is enough. */
270 if (i_size > rbuf_size[0]) {
272 * Try to allocate secondary buffer. If that fails fallback to
273 * using single buffering. Use previous memory allocation size
274 * as baseline for possible allocation size.
276 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
280 if (!(file->f_mode & FMODE_READ)) {
281 file->f_mode |= FMODE_READ;
285 for (offset = 0; offset < i_size; offset += rbuf_len) {
286 if (!rbuf[1] && offset) {
287 /* Not using two buffers, and it is not the first
288 * read/request, wait for the completion of the
289 * previous ahash_update() request.
291 rc = ahash_wait(ahash_rc, &res);
296 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
297 rc = integrity_kernel_read(file, offset, rbuf[active],
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);
324 file->f_mode &= ~FMODE_READ;
325 ima_free_pages(rbuf[0], rbuf_size[0]);
326 ima_free_pages(rbuf[1], rbuf_size[1]);
329 ahash_request_set_crypt(req, NULL, hash->digest, 0);
330 rc = ahash_wait(crypto_ahash_final(req), &res);
333 ahash_request_free(req);
337 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
339 struct crypto_ahash *tfm;
342 tfm = ima_alloc_atfm(hash->algo);
346 rc = ima_calc_file_hash_atfm(file, hash, tfm);
353 static int ima_calc_file_hash_tfm(struct file *file,
354 struct ima_digest_data *hash,
355 struct crypto_shash *tfm)
357 loff_t i_size, offset = 0;
360 SHASH_DESC_ON_STACK(shash, tfm);
365 hash->length = crypto_shash_digestsize(tfm);
367 rc = crypto_shash_init(shash);
371 i_size = i_size_read(file_inode(file));
376 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
380 if (!(file->f_mode & FMODE_READ)) {
381 file->f_mode |= FMODE_READ;
385 while (offset < i_size) {
388 rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
397 rc = crypto_shash_update(shash, rbuf, rbuf_len);
402 file->f_mode &= ~FMODE_READ;
406 rc = crypto_shash_final(shash, hash->digest);
410 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
412 struct crypto_shash *tfm;
415 tfm = ima_alloc_tfm(hash->algo);
419 rc = ima_calc_file_hash_tfm(file, hash, tfm);
427 * ima_calc_file_hash - calculate file hash
429 * Asynchronous hash (ahash) allows using HW acceleration for calculating
430 * a hash. ahash performance varies for different data sizes on different
431 * crypto accelerators. shash performance might be better for smaller files.
432 * The 'ima.ahash_minsize' module parameter allows specifying the best
433 * minimum file size for using ahash on the system.
435 * If the ima.ahash_minsize parameter is not specified, this function uses
436 * shash for the hash calculation. If ahash fails, it falls back to using
439 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
444 i_size = i_size_read(file_inode(file));
446 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
447 rc = ima_calc_file_ahash(file, hash);
452 return ima_calc_file_shash(file, hash);
456 * Calculate the hash of template data
458 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
459 struct ima_template_desc *td,
461 struct ima_digest_data *hash,
462 struct crypto_shash *tfm)
464 SHASH_DESC_ON_STACK(shash, tfm);
470 hash->length = crypto_shash_digestsize(tfm);
472 rc = crypto_shash_init(shash);
476 for (i = 0; i < num_fields; i++) {
477 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
478 u8 *data_to_hash = field_data[i].data;
479 u32 datalen = field_data[i].len;
481 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
482 rc = crypto_shash_update(shash,
483 (const u8 *) &field_data[i].len,
484 sizeof(field_data[i].len));
487 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
488 memcpy(buffer, data_to_hash, datalen);
489 data_to_hash = buffer;
490 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
492 rc = crypto_shash_update(shash, data_to_hash, datalen);
498 rc = crypto_shash_final(shash, hash->digest);
503 int ima_calc_field_array_hash(struct ima_field_data *field_data,
504 struct ima_template_desc *desc, int num_fields,
505 struct ima_digest_data *hash)
507 struct crypto_shash *tfm;
510 tfm = ima_alloc_tfm(hash->algo);
514 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
522 static int calc_buffer_ahash_atfm(const void *buf, loff_t len,
523 struct ima_digest_data *hash,
524 struct crypto_ahash *tfm)
526 struct ahash_request *req;
527 struct scatterlist sg;
528 struct ahash_completion res;
529 int rc, ahash_rc = 0;
531 hash->length = crypto_ahash_digestsize(tfm);
533 req = ahash_request_alloc(tfm, GFP_KERNEL);
537 init_completion(&res.completion);
538 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
539 CRYPTO_TFM_REQ_MAY_SLEEP,
540 ahash_complete, &res);
542 rc = ahash_wait(crypto_ahash_init(req), &res);
546 sg_init_one(&sg, buf, len);
547 ahash_request_set_crypt(req, &sg, NULL, len);
549 ahash_rc = crypto_ahash_update(req);
551 /* wait for the update request to complete */
552 rc = ahash_wait(ahash_rc, &res);
554 ahash_request_set_crypt(req, NULL, hash->digest, 0);
555 rc = ahash_wait(crypto_ahash_final(req), &res);
558 ahash_request_free(req);
562 static int calc_buffer_ahash(const void *buf, loff_t len,
563 struct ima_digest_data *hash)
565 struct crypto_ahash *tfm;
568 tfm = ima_alloc_atfm(hash->algo);
572 rc = calc_buffer_ahash_atfm(buf, len, hash, tfm);
579 static int calc_buffer_shash_tfm(const void *buf, loff_t size,
580 struct ima_digest_data *hash,
581 struct crypto_shash *tfm)
583 SHASH_DESC_ON_STACK(shash, tfm);
590 hash->length = crypto_shash_digestsize(tfm);
592 rc = crypto_shash_init(shash);
597 len = size < PAGE_SIZE ? size : PAGE_SIZE;
598 rc = crypto_shash_update(shash, buf, len);
606 rc = crypto_shash_final(shash, hash->digest);
610 static int calc_buffer_shash(const void *buf, loff_t len,
611 struct ima_digest_data *hash)
613 struct crypto_shash *tfm;
616 tfm = ima_alloc_tfm(hash->algo);
620 rc = calc_buffer_shash_tfm(buf, len, hash, tfm);
626 int ima_calc_buffer_hash(const void *buf, loff_t len,
627 struct ima_digest_data *hash)
631 if (ima_ahash_minsize && len >= ima_ahash_minsize) {
632 rc = calc_buffer_ahash(buf, len, hash);
637 return calc_buffer_shash(buf, len, hash);
640 static void __init ima_pcrread(int idx, u8 *pcr)
645 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
646 pr_err("Error Communicating to TPM chip\n");
650 * Calculate the boot aggregate hash
652 static int __init ima_calc_boot_aggregate_tfm(char *digest,
653 struct crypto_shash *tfm)
655 u8 pcr_i[TPM_DIGEST_SIZE];
657 SHASH_DESC_ON_STACK(shash, tfm);
662 rc = crypto_shash_init(shash);
666 /* cumulative sha1 over tpm registers 0-7 */
667 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
668 ima_pcrread(i, pcr_i);
669 /* now accumulate with current aggregate */
670 rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
673 crypto_shash_final(shash, digest);
677 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
679 struct crypto_shash *tfm;
682 tfm = ima_alloc_tfm(hash->algo);
686 hash->length = crypto_shash_digestsize(tfm);
687 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);