]>
git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - security/integrity/ima/ima_crypto.c
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/file.h>
20 #include <linux/crypto.h>
21 #include <linux/scatterlist.h>
22 #include <linux/err.h>
23 #include <linux/slab.h>
24 #include <crypto/hash.h>
25 #include <crypto/hash_info.h>
28 static struct crypto_shash
*ima_shash_tfm
;
31 * ima_kernel_read - read file content
33 * This is a function for reading file content instead of kernel_read().
34 * It does not perform locking checks to ensure it cannot be blocked.
35 * It does not perform security checks because it is irrelevant for IMA.
38 static int ima_kernel_read(struct file
*file
, loff_t offset
,
39 char *addr
, unsigned long count
)
42 char __user
*buf
= addr
;
45 if (!(file
->f_mode
& FMODE_READ
))
47 if (!file
->f_op
->read
&& !file
->f_op
->aio_read
)
53 ret
= file
->f_op
->read(file
, buf
, count
, &offset
);
55 ret
= do_sync_read(file
, buf
, count
, &offset
);
60 int ima_init_crypto(void)
64 ima_shash_tfm
= crypto_alloc_shash(hash_algo_name
[ima_hash_algo
], 0, 0);
65 if (IS_ERR(ima_shash_tfm
)) {
66 rc
= PTR_ERR(ima_shash_tfm
);
67 pr_err("Can not allocate %s (reason: %ld)\n",
68 hash_algo_name
[ima_hash_algo
], rc
);
74 static struct crypto_shash
*ima_alloc_tfm(enum hash_algo algo
)
76 struct crypto_shash
*tfm
= ima_shash_tfm
;
79 if (algo
!= ima_hash_algo
&& algo
< HASH_ALGO__LAST
) {
80 tfm
= crypto_alloc_shash(hash_algo_name
[algo
], 0, 0);
83 pr_err("Can not allocate %s (reason: %d)\n",
84 hash_algo_name
[algo
], rc
);
90 static void ima_free_tfm(struct crypto_shash
*tfm
)
92 if (tfm
!= ima_shash_tfm
)
93 crypto_free_shash(tfm
);
97 * Calculate the MD5/SHA1 file digest
99 static int ima_calc_file_hash_tfm(struct file
*file
,
100 struct ima_digest_data
*hash
,
101 struct crypto_shash
*tfm
)
103 loff_t i_size
, offset
= 0;
107 struct shash_desc shash
;
108 char ctx
[crypto_shash_descsize(tfm
)];
111 desc
.shash
.tfm
= tfm
;
112 desc
.shash
.flags
= 0;
114 hash
->length
= crypto_shash_digestsize(tfm
);
116 rc
= crypto_shash_init(&desc
.shash
);
120 i_size
= i_size_read(file_inode(file
));
125 rbuf
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
129 if (!(file
->f_mode
& FMODE_READ
)) {
130 file
->f_mode
|= FMODE_READ
;
134 while (offset
< i_size
) {
137 rbuf_len
= ima_kernel_read(file
, offset
, rbuf
, PAGE_SIZE
);
146 rc
= crypto_shash_update(&desc
.shash
, rbuf
, rbuf_len
);
151 file
->f_mode
&= ~FMODE_READ
;
155 rc
= crypto_shash_final(&desc
.shash
, hash
->digest
);
159 int ima_calc_file_hash(struct file
*file
, struct ima_digest_data
*hash
)
161 struct crypto_shash
*tfm
;
164 tfm
= ima_alloc_tfm(hash
->algo
);
168 rc
= ima_calc_file_hash_tfm(file
, hash
, tfm
);
176 * Calculate the hash of template data
178 static int ima_calc_field_array_hash_tfm(struct ima_field_data
*field_data
,
179 struct ima_template_desc
*td
,
181 struct ima_digest_data
*hash
,
182 struct crypto_shash
*tfm
)
185 struct shash_desc shash
;
186 char ctx
[crypto_shash_descsize(tfm
)];
190 desc
.shash
.tfm
= tfm
;
191 desc
.shash
.flags
= 0;
193 hash
->length
= crypto_shash_digestsize(tfm
);
195 rc
= crypto_shash_init(&desc
.shash
);
199 for (i
= 0; i
< num_fields
; i
++) {
200 u8 buffer
[IMA_EVENT_NAME_LEN_MAX
+ 1] = { 0 };
201 u8
*data_to_hash
= field_data
[i
].data
;
202 u32 datalen
= field_data
[i
].len
;
204 if (strcmp(td
->name
, IMA_TEMPLATE_IMA_NAME
) != 0) {
205 rc
= crypto_shash_update(&desc
.shash
,
206 (const u8
*) &field_data
[i
].len
,
207 sizeof(field_data
[i
].len
));
210 } else if (strcmp(td
->fields
[i
]->field_id
, "n") == 0) {
211 memcpy(buffer
, data_to_hash
, datalen
);
212 data_to_hash
= buffer
;
213 datalen
= IMA_EVENT_NAME_LEN_MAX
+ 1;
215 rc
= crypto_shash_update(&desc
.shash
, data_to_hash
, datalen
);
221 rc
= crypto_shash_final(&desc
.shash
, hash
->digest
);
226 int ima_calc_field_array_hash(struct ima_field_data
*field_data
,
227 struct ima_template_desc
*desc
, int num_fields
,
228 struct ima_digest_data
*hash
)
230 struct crypto_shash
*tfm
;
233 tfm
= ima_alloc_tfm(hash
->algo
);
237 rc
= ima_calc_field_array_hash_tfm(field_data
, desc
, num_fields
,
245 static void __init
ima_pcrread(int idx
, u8
*pcr
)
250 if (tpm_pcr_read(TPM_ANY_NUM
, idx
, pcr
) != 0)
251 pr_err("Error Communicating to TPM chip\n");
255 * Calculate the boot aggregate hash
257 static int __init
ima_calc_boot_aggregate_tfm(char *digest
,
258 struct crypto_shash
*tfm
)
260 u8 pcr_i
[TPM_DIGEST_SIZE
];
263 struct shash_desc shash
;
264 char ctx
[crypto_shash_descsize(tfm
)];
267 desc
.shash
.tfm
= tfm
;
268 desc
.shash
.flags
= 0;
270 rc
= crypto_shash_init(&desc
.shash
);
274 /* cumulative sha1 over tpm registers 0-7 */
275 for (i
= TPM_PCR0
; i
< TPM_PCR8
; i
++) {
276 ima_pcrread(i
, pcr_i
);
277 /* now accumulate with current aggregate */
278 rc
= crypto_shash_update(&desc
.shash
, pcr_i
, TPM_DIGEST_SIZE
);
281 crypto_shash_final(&desc
.shash
, digest
);
285 int __init
ima_calc_boot_aggregate(struct ima_digest_data
*hash
)
287 struct crypto_shash
*tfm
;
290 tfm
= ima_alloc_tfm(hash
->algo
);
294 hash
->length
= crypto_shash_digestsize(tfm
);
295 rc
= ima_calc_boot_aggregate_tfm(hash
->digest
, tfm
);