Linux-2.6.12-rc2
[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 <asm/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         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
35 int 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
50 void crypto_free_hmac_block(struct crypto_tfm *tfm)
51 {
52         if (tfm->crt_digest.dit_hmac_block)
53                 kfree(tfm->crt_digest.dit_hmac_block);
54 }
55
56 void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
57 {
58         unsigned int i;
59         struct scatterlist tmp;
60         char *ipad = tfm->crt_digest.dit_hmac_block;
61         
62         if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
63                 hash_key(tfm, key, *keylen);
64                 *keylen = crypto_tfm_alg_digestsize(tfm);
65         }
66
67         memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
68         memcpy(ipad, key, *keylen);
69
70         for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
71                 ipad[i] ^= 0x36;
72
73         tmp.page = virt_to_page(ipad);
74         tmp.offset = offset_in_page(ipad);
75         tmp.length = crypto_tfm_alg_blocksize(tfm);
76         
77         crypto_digest_init(tfm);
78         crypto_digest_update(tfm, &tmp, 1);
79 }
80
81 void crypto_hmac_update(struct crypto_tfm *tfm,
82                         struct scatterlist *sg, unsigned int nsg)
83 {
84         crypto_digest_update(tfm, sg, nsg);
85 }
86
87 void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
88                        unsigned int *keylen, u8 *out)
89 {
90         unsigned int i;
91         struct scatterlist tmp;
92         char *opad = tfm->crt_digest.dit_hmac_block;
93         
94         if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
95                 hash_key(tfm, key, *keylen);
96                 *keylen = crypto_tfm_alg_digestsize(tfm);
97         }
98
99         crypto_digest_final(tfm, out);
100
101         memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
102         memcpy(opad, key, *keylen);
103                 
104         for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
105                 opad[i] ^= 0x5c;
106
107         tmp.page = virt_to_page(opad);
108         tmp.offset = offset_in_page(opad);
109         tmp.length = crypto_tfm_alg_blocksize(tfm);
110
111         crypto_digest_init(tfm);
112         crypto_digest_update(tfm, &tmp, 1);
113         
114         tmp.page = virt_to_page(out);
115         tmp.offset = offset_in_page(out);
116         tmp.length = crypto_tfm_alg_digestsize(tfm);
117         
118         crypto_digest_update(tfm, &tmp, 1);
119         crypto_digest_final(tfm, out);
120 }
121
122 void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
123                  struct scatterlist *sg, unsigned int nsg, u8 *out)
124 {
125         crypto_hmac_init(tfm, key, keylen);
126         crypto_hmac_update(tfm, sg, nsg);
127         crypto_hmac_final(tfm, key, keylen, out);
128 }
129
130 EXPORT_SYMBOL_GPL(crypto_hmac_init);
131 EXPORT_SYMBOL_GPL(crypto_hmac_update);
132 EXPORT_SYMBOL_GPL(crypto_hmac_final);
133 EXPORT_SYMBOL_GPL(crypto_hmac);
134