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>
27 #include <crypto/hash_info.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 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;
71 * ima_kernel_read - read file content
73 * This is a function for reading file content instead of kernel_read().
74 * It does not perform locking checks to ensure it cannot be blocked.
75 * It does not perform security checks because it is irrelevant for IMA.
78 static int ima_kernel_read(struct file *file, loff_t offset,
79 char *addr, unsigned long count)
82 char __user *buf = addr;
83 ssize_t ret = -EINVAL;
85 if (!(file->f_mode & FMODE_READ))
91 ret = file->f_op->read(file, buf, count, &offset);
92 else if (file->f_op->aio_read)
93 ret = do_sync_read(file, buf, count, &offset);
94 else if (file->f_op->read_iter)
95 ret = new_sync_read(file, buf, count, &offset);
100 int __init ima_init_crypto(void)
104 ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
105 if (IS_ERR(ima_shash_tfm)) {
106 rc = PTR_ERR(ima_shash_tfm);
107 pr_err("Can not allocate %s (reason: %ld)\n",
108 hash_algo_name[ima_hash_algo], rc);
114 static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
116 struct crypto_shash *tfm = ima_shash_tfm;
119 if (algo < 0 || algo >= HASH_ALGO__LAST)
120 algo = ima_hash_algo;
122 if (algo != ima_hash_algo) {
123 tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
126 pr_err("Can not allocate %s (reason: %d)\n",
127 hash_algo_name[algo], rc);
133 static void ima_free_tfm(struct crypto_shash *tfm)
135 if (tfm != ima_shash_tfm)
136 crypto_free_shash(tfm);
140 * ima_alloc_pages() - Allocate contiguous pages.
141 * @max_size: Maximum amount of memory to allocate.
142 * @allocated_size: Returned size of actual allocation.
143 * @last_warn: Should the min_size allocation warn or not.
145 * Tries to do opportunistic allocation for memory first trying to allocate
146 * max_size amount of memory and then splitting that until zero order is
147 * reached. Allocation is tried without generating allocation warnings unless
148 * last_warn is set. Last_warn set affects only last allocation of zero order.
150 * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
152 * Return pointer to allocated memory, or NULL on failure.
154 static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
158 int order = ima_maxorder;
159 gfp_t gfp_mask = __GFP_WAIT | __GFP_NOWARN | __GFP_NORETRY;
162 order = min(get_order(max_size), order);
164 for (; order; order--) {
165 ptr = (void *)__get_free_pages(gfp_mask, order);
167 *allocated_size = PAGE_SIZE << order;
172 /* order is zero - one page */
174 gfp_mask = GFP_KERNEL;
177 gfp_mask |= __GFP_NOWARN;
179 ptr = (void *)__get_free_pages(gfp_mask, 0);
181 *allocated_size = PAGE_SIZE;
190 * ima_free_pages() - Free pages allocated by ima_alloc_pages().
191 * @ptr: Pointer to allocated pages.
192 * @size: Size of allocated buffer.
194 static void ima_free_pages(void *ptr, size_t size)
198 free_pages((unsigned long)ptr, get_order(size));
201 static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
203 struct crypto_ahash *tfm = ima_ahash_tfm;
206 if (algo < 0 || algo >= HASH_ALGO__LAST)
207 algo = ima_hash_algo;
209 if (algo != ima_hash_algo || !tfm) {
210 tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
212 if (algo == ima_hash_algo)
216 pr_err("Can not allocate %s (reason: %d)\n",
217 hash_algo_name[algo], rc);
223 static void ima_free_atfm(struct crypto_ahash *tfm)
225 if (tfm != ima_ahash_tfm)
226 crypto_free_ahash(tfm);
229 static void ahash_complete(struct crypto_async_request *req, int err)
231 struct ahash_completion *res = req->data;
233 if (err == -EINPROGRESS)
236 complete(&res->completion);
239 static int ahash_wait(int err, struct ahash_completion *res)
246 wait_for_completion(&res->completion);
247 reinit_completion(&res->completion);
251 pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
257 static int ima_calc_file_hash_atfm(struct file *file,
258 struct ima_digest_data *hash,
259 struct crypto_ahash *tfm)
261 loff_t i_size, offset;
262 char *rbuf[2] = { NULL, };
263 int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0;
264 struct ahash_request *req;
265 struct scatterlist sg[1];
266 struct ahash_completion res;
269 hash->length = crypto_ahash_digestsize(tfm);
271 req = ahash_request_alloc(tfm, GFP_KERNEL);
275 init_completion(&res.completion);
276 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
277 CRYPTO_TFM_REQ_MAY_SLEEP,
278 ahash_complete, &res);
280 rc = ahash_wait(crypto_ahash_init(req), &res);
284 i_size = i_size_read(file_inode(file));
290 * Try to allocate maximum size of memory.
291 * Fail if even a single page cannot be allocated.
293 rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
299 /* Only allocate one buffer if that is enough. */
300 if (i_size > rbuf_size[0]) {
302 * Try to allocate secondary buffer. If that fails fallback to
303 * using single buffering. Use previous memory allocation size
304 * as baseline for possible allocation size.
306 rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
310 if (!(file->f_mode & FMODE_READ)) {
311 file->f_mode |= FMODE_READ;
315 for (offset = 0; offset < i_size; offset += rbuf_len) {
316 if (!rbuf[1] && offset) {
317 /* Not using two buffers, and it is not the first
318 * read/request, wait for the completion of the
319 * previous ahash_update() request.
321 rc = ahash_wait(ahash_rc, &res);
326 rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
327 rc = ima_kernel_read(file, offset, rbuf[active], rbuf_len);
331 if (rbuf[1] && offset) {
332 /* Using two buffers, and it is not the first
333 * read/request, wait for the completion of the
334 * previous ahash_update() request.
336 rc = ahash_wait(ahash_rc, &res);
341 sg_init_one(&sg[0], rbuf[active], rbuf_len);
342 ahash_request_set_crypt(req, sg, NULL, rbuf_len);
344 ahash_rc = crypto_ahash_update(req);
347 active = !active; /* swap buffers, if we use two */
349 /* wait for the last update request to complete */
350 rc = ahash_wait(ahash_rc, &res);
353 file->f_mode &= ~FMODE_READ;
354 ima_free_pages(rbuf[0], rbuf_size[0]);
355 ima_free_pages(rbuf[1], rbuf_size[1]);
358 ahash_request_set_crypt(req, NULL, hash->digest, 0);
359 rc = ahash_wait(crypto_ahash_final(req), &res);
362 ahash_request_free(req);
366 static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
368 struct crypto_ahash *tfm;
371 tfm = ima_alloc_atfm(hash->algo);
375 rc = ima_calc_file_hash_atfm(file, hash, tfm);
382 static int ima_calc_file_hash_tfm(struct file *file,
383 struct ima_digest_data *hash,
384 struct crypto_shash *tfm)
386 loff_t i_size, offset = 0;
389 SHASH_DESC_ON_STACK(shash, tfm);
394 hash->length = crypto_shash_digestsize(tfm);
396 rc = crypto_shash_init(shash);
400 i_size = i_size_read(file_inode(file));
405 rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
409 if (!(file->f_mode & FMODE_READ)) {
410 file->f_mode |= FMODE_READ;
414 while (offset < i_size) {
417 rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);
426 rc = crypto_shash_update(shash, rbuf, rbuf_len);
431 file->f_mode &= ~FMODE_READ;
435 rc = crypto_shash_final(shash, hash->digest);
439 static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
441 struct crypto_shash *tfm;
444 tfm = ima_alloc_tfm(hash->algo);
448 rc = ima_calc_file_hash_tfm(file, hash, tfm);
456 * ima_calc_file_hash - calculate file hash
458 * Asynchronous hash (ahash) allows using HW acceleration for calculating
459 * a hash. ahash performance varies for different data sizes on different
460 * crypto accelerators. shash performance might be better for smaller files.
461 * The 'ima.ahash_minsize' module parameter allows specifying the best
462 * minimum file size for using ahash on the system.
464 * If the ima.ahash_minsize parameter is not specified, this function uses
465 * shash for the hash calculation. If ahash fails, it falls back to using
468 int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
473 i_size = i_size_read(file_inode(file));
475 if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
476 rc = ima_calc_file_ahash(file, hash);
481 return ima_calc_file_shash(file, hash);
485 * Calculate the hash of template data
487 static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
488 struct ima_template_desc *td,
490 struct ima_digest_data *hash,
491 struct crypto_shash *tfm)
493 SHASH_DESC_ON_STACK(shash, tfm);
499 hash->length = crypto_shash_digestsize(tfm);
501 rc = crypto_shash_init(shash);
505 for (i = 0; i < num_fields; i++) {
506 u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
507 u8 *data_to_hash = field_data[i].data;
508 u32 datalen = field_data[i].len;
510 if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
511 rc = crypto_shash_update(shash,
512 (const u8 *) &field_data[i].len,
513 sizeof(field_data[i].len));
516 } else if (strcmp(td->fields[i]->field_id, "n") == 0) {
517 memcpy(buffer, data_to_hash, datalen);
518 data_to_hash = buffer;
519 datalen = IMA_EVENT_NAME_LEN_MAX + 1;
521 rc = crypto_shash_update(shash, data_to_hash, datalen);
527 rc = crypto_shash_final(shash, hash->digest);
532 int ima_calc_field_array_hash(struct ima_field_data *field_data,
533 struct ima_template_desc *desc, int num_fields,
534 struct ima_digest_data *hash)
536 struct crypto_shash *tfm;
539 tfm = ima_alloc_tfm(hash->algo);
543 rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
551 static void __init ima_pcrread(int idx, u8 *pcr)
556 if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
557 pr_err("Error Communicating to TPM chip\n");
561 * Calculate the boot aggregate hash
563 static int __init ima_calc_boot_aggregate_tfm(char *digest,
564 struct crypto_shash *tfm)
566 u8 pcr_i[TPM_DIGEST_SIZE];
568 SHASH_DESC_ON_STACK(shash, tfm);
573 rc = crypto_shash_init(shash);
577 /* cumulative sha1 over tpm registers 0-7 */
578 for (i = TPM_PCR0; i < TPM_PCR8; i++) {
579 ima_pcrread(i, pcr_i);
580 /* now accumulate with current aggregate */
581 rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
584 crypto_shash_final(shash, digest);
588 int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
590 struct crypto_shash *tfm;
593 tfm = ima_alloc_tfm(hash->algo);
597 hash->length = crypto_shash_digestsize(tfm);
598 rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);