Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Cryptographic API.
3 *
4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 *
8 * The HMAC implementation is derived from USAGI.
9 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 *
16 */
17#include <linux/crypto.h>
18#include <linux/mm.h>
19#include <linux/highmem.h>
20#include <linux/slab.h>
21#include <asm/scatterlist.h>
22#include "internal.h"
23
24static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
25{
26 struct scatterlist tmp;
27
28 tmp.page = virt_to_page(key);
29 tmp.offset = offset_in_page(key);
30 tmp.length = keylen;
31 crypto_digest_digest(tfm, &tmp, 1, key);
32
33}
34
35int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
36{
37 int ret = 0;
38
39 BUG_ON(!crypto_tfm_alg_blocksize(tfm));
40
41 tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
42 GFP_KERNEL);
43 if (tfm->crt_digest.dit_hmac_block == NULL)
44 ret = -ENOMEM;
45
46 return ret;
47
48}
49
50void crypto_free_hmac_block(struct crypto_tfm *tfm)
51{
52 kfree(tfm->crt_digest.dit_hmac_block);
53}
54
55void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
56{
57 unsigned int i;
58 struct scatterlist tmp;
59 char *ipad = tfm->crt_digest.dit_hmac_block;
60
61 if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
62 hash_key(tfm, key, *keylen);
63 *keylen = crypto_tfm_alg_digestsize(tfm);
64 }
65
66 memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
67 memcpy(ipad, key, *keylen);
68
69 for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
70 ipad[i] ^= 0x36;
71
72 tmp.page = virt_to_page(ipad);
73 tmp.offset = offset_in_page(ipad);
74 tmp.length = crypto_tfm_alg_blocksize(tfm);
75
76 crypto_digest_init(tfm);
77 crypto_digest_update(tfm, &tmp, 1);
78}
79
80void crypto_hmac_update(struct crypto_tfm *tfm,
81 struct scatterlist *sg, unsigned int nsg)
82{
83 crypto_digest_update(tfm, sg, nsg);
84}
85
86void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
87 unsigned int *keylen, u8 *out)
88{
89 unsigned int i;
90 struct scatterlist tmp;
91 char *opad = tfm->crt_digest.dit_hmac_block;
92
93 if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
94 hash_key(tfm, key, *keylen);
95 *keylen = crypto_tfm_alg_digestsize(tfm);
96 }
97
98 crypto_digest_final(tfm, out);
99
100 memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
101 memcpy(opad, key, *keylen);
102
103 for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
104 opad[i] ^= 0x5c;
105
106 tmp.page = virt_to_page(opad);
107 tmp.offset = offset_in_page(opad);
108 tmp.length = crypto_tfm_alg_blocksize(tfm);
109
110 crypto_digest_init(tfm);
111 crypto_digest_update(tfm, &tmp, 1);
112
113 tmp.page = virt_to_page(out);
114 tmp.offset = offset_in_page(out);
115 tmp.length = crypto_tfm_alg_digestsize(tfm);
116
117 crypto_digest_update(tfm, &tmp, 1);
118 crypto_digest_final(tfm, out);
119}
120
121void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
122 struct scatterlist *sg, unsigned int nsg, u8 *out)
123{
124 crypto_hmac_init(tfm, key, keylen);
125 crypto_hmac_update(tfm, sg, nsg);
126 crypto_hmac_final(tfm, key, keylen, out);
127}
128
129EXPORT_SYMBOL_GPL(crypto_hmac_init);
130EXPORT_SYMBOL_GPL(crypto_hmac_update);
131EXPORT_SYMBOL_GPL(crypto_hmac_final);
132EXPORT_SYMBOL_GPL(crypto_hmac);
133