[PATCH] Use sg_set_buf/sg_init_one where applicable
[linux-2.6.git] / crypto / hmac.c
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 <linux/scatterlist.h>
22 #include "internal.h"
23
24 static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
25 {
26         struct scatterlist tmp;
27         
28         sg_set_buf(&tmp, key, keylen);
29         crypto_digest_digest(tfm, &tmp, 1, key);
30 }
31
32 int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
33 {
34         int ret = 0;
35
36         BUG_ON(!crypto_tfm_alg_blocksize(tfm));
37         
38         tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
39                                                  GFP_KERNEL);
40         if (tfm->crt_digest.dit_hmac_block == NULL)
41                 ret = -ENOMEM;
42
43         return ret;
44                 
45 }
46
47 void crypto_free_hmac_block(struct crypto_tfm *tfm)
48 {
49         kfree(tfm->crt_digest.dit_hmac_block);
50 }
51
52 void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
53 {
54         unsigned int i;
55         struct scatterlist tmp;
56         char *ipad = tfm->crt_digest.dit_hmac_block;
57         
58         if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
59                 hash_key(tfm, key, *keylen);
60                 *keylen = crypto_tfm_alg_digestsize(tfm);
61         }
62
63         memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
64         memcpy(ipad, key, *keylen);
65
66         for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
67                 ipad[i] ^= 0x36;
68
69         sg_set_buf(&tmp, ipad, crypto_tfm_alg_blocksize(tfm));
70         
71         crypto_digest_init(tfm);
72         crypto_digest_update(tfm, &tmp, 1);
73 }
74
75 void crypto_hmac_update(struct crypto_tfm *tfm,
76                         struct scatterlist *sg, unsigned int nsg)
77 {
78         crypto_digest_update(tfm, sg, nsg);
79 }
80
81 void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
82                        unsigned int *keylen, u8 *out)
83 {
84         unsigned int i;
85         struct scatterlist tmp;
86         char *opad = tfm->crt_digest.dit_hmac_block;
87         
88         if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
89                 hash_key(tfm, key, *keylen);
90                 *keylen = crypto_tfm_alg_digestsize(tfm);
91         }
92
93         crypto_digest_final(tfm, out);
94
95         memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
96         memcpy(opad, key, *keylen);
97                 
98         for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
99                 opad[i] ^= 0x5c;
100
101         sg_set_buf(&tmp, opad, crypto_tfm_alg_blocksize(tfm));
102
103         crypto_digest_init(tfm);
104         crypto_digest_update(tfm, &tmp, 1);
105         
106         sg_set_buf(&tmp, out, crypto_tfm_alg_digestsize(tfm));
107         
108         crypto_digest_update(tfm, &tmp, 1);
109         crypto_digest_final(tfm, out);
110 }
111
112 void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
113                  struct scatterlist *sg, unsigned int nsg, u8 *out)
114 {
115         crypto_hmac_init(tfm, key, keylen);
116         crypto_hmac_update(tfm, sg, nsg);
117         crypto_hmac_final(tfm, key, keylen, out);
118 }
119
120 EXPORT_SYMBOL_GPL(crypto_hmac_init);
121 EXPORT_SYMBOL_GPL(crypto_hmac_update);
122 EXPORT_SYMBOL_GPL(crypto_hmac_final);
123 EXPORT_SYMBOL_GPL(crypto_hmac);
124