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;
390 struct shash_desc shash
;
391 char ctx
[crypto_shash_descsize(tfm
)];
394 desc
.shash
.tfm
= tfm
;
395 desc
.shash
.flags
= 0;
397 hash
->length
= crypto_shash_digestsize(tfm
);
399 rc
= crypto_shash_init(&desc
.shash
);
403 i_size
= i_size_read(file_inode(file
));
408 rbuf
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
412 if (!(file
->f_mode
& FMODE_READ
)) {
413 file
->f_mode
|= FMODE_READ
;
417 while (offset
< i_size
) {
420 rbuf_len
= ima_kernel_read(file
, offset
, rbuf
, PAGE_SIZE
);
429 rc
= crypto_shash_update(&desc
.shash
, rbuf
, rbuf_len
);
434 file
->f_mode
&= ~FMODE_READ
;
438 rc
= crypto_shash_final(&desc
.shash
, hash
->digest
);
442 static int ima_calc_file_shash(struct file
*file
, struct ima_digest_data
*hash
)
444 struct crypto_shash
*tfm
;
447 tfm
= ima_alloc_tfm(hash
->algo
);
451 rc
= ima_calc_file_hash_tfm(file
, hash
, tfm
);
459 * ima_calc_file_hash - calculate file hash
461 * Asynchronous hash (ahash) allows using HW acceleration for calculating
462 * a hash. ahash performance varies for different data sizes on different
463 * crypto accelerators. shash performance might be better for smaller files.
464 * The 'ima.ahash_minsize' module parameter allows specifying the best
465 * minimum file size for using ahash on the system.
467 * If the ima.ahash_minsize parameter is not specified, this function uses
468 * shash for the hash calculation. If ahash fails, it falls back to using
471 int ima_calc_file_hash(struct file
*file
, struct ima_digest_data
*hash
)
476 i_size
= i_size_read(file_inode(file
));
478 if (ima_ahash_minsize
&& i_size
>= ima_ahash_minsize
) {
479 rc
= ima_calc_file_ahash(file
, hash
);
484 return ima_calc_file_shash(file
, hash
);
488 * Calculate the hash of template data
490 static int ima_calc_field_array_hash_tfm(struct ima_field_data
*field_data
,
491 struct ima_template_desc
*td
,
493 struct ima_digest_data
*hash
,
494 struct crypto_shash
*tfm
)
497 struct shash_desc shash
;
498 char ctx
[crypto_shash_descsize(tfm
)];
502 desc
.shash
.tfm
= tfm
;
503 desc
.shash
.flags
= 0;
505 hash
->length
= crypto_shash_digestsize(tfm
);
507 rc
= crypto_shash_init(&desc
.shash
);
511 for (i
= 0; i
< num_fields
; i
++) {
512 u8 buffer
[IMA_EVENT_NAME_LEN_MAX
+ 1] = { 0 };
513 u8
*data_to_hash
= field_data
[i
].data
;
514 u32 datalen
= field_data
[i
].len
;
516 if (strcmp(td
->name
, IMA_TEMPLATE_IMA_NAME
) != 0) {
517 rc
= crypto_shash_update(&desc
.shash
,
518 (const u8
*) &field_data
[i
].len
,
519 sizeof(field_data
[i
].len
));
522 } else if (strcmp(td
->fields
[i
]->field_id
, "n") == 0) {
523 memcpy(buffer
, data_to_hash
, datalen
);
524 data_to_hash
= buffer
;
525 datalen
= IMA_EVENT_NAME_LEN_MAX
+ 1;
527 rc
= crypto_shash_update(&desc
.shash
, data_to_hash
, datalen
);
533 rc
= crypto_shash_final(&desc
.shash
, hash
->digest
);
538 int ima_calc_field_array_hash(struct ima_field_data
*field_data
,
539 struct ima_template_desc
*desc
, int num_fields
,
540 struct ima_digest_data
*hash
)
542 struct crypto_shash
*tfm
;
545 tfm
= ima_alloc_tfm(hash
->algo
);
549 rc
= ima_calc_field_array_hash_tfm(field_data
, desc
, num_fields
,
557 static void __init
ima_pcrread(int idx
, u8
*pcr
)
562 if (tpm_pcr_read(TPM_ANY_NUM
, idx
, pcr
) != 0)
563 pr_err("Error Communicating to TPM chip\n");
567 * Calculate the boot aggregate hash
569 static int __init
ima_calc_boot_aggregate_tfm(char *digest
,
570 struct crypto_shash
*tfm
)
572 u8 pcr_i
[TPM_DIGEST_SIZE
];
575 struct shash_desc shash
;
576 char ctx
[crypto_shash_descsize(tfm
)];
579 desc
.shash
.tfm
= tfm
;
580 desc
.shash
.flags
= 0;
582 rc
= crypto_shash_init(&desc
.shash
);
586 /* cumulative sha1 over tpm registers 0-7 */
587 for (i
= TPM_PCR0
; i
< TPM_PCR8
; i
++) {
588 ima_pcrread(i
, pcr_i
);
589 /* now accumulate with current aggregate */
590 rc
= crypto_shash_update(&desc
.shash
, pcr_i
, TPM_DIGEST_SIZE
);
593 crypto_shash_final(&desc
.shash
, digest
);
597 int __init
ima_calc_boot_aggregate(struct ima_digest_data
*hash
)
599 struct crypto_shash
*tfm
;
602 tfm
= ima_alloc_tfm(hash
->algo
);
606 hash
->length
= crypto_shash_digestsize(tfm
);
607 rc
= ima_calc_boot_aggregate_tfm(hash
->digest
, tfm
);