1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
/*
* HMAC (RFC-2104) implementation.
*
* Copyright (c) 2004 Andrey Panin <pazke@donpac.ru>
* Copyright (c) 2011-2012 Florian Zeitz <florob@babelmonkeys.de>
*
* This software is released under the MIT license.
*/
#include "lib.h"
#include "hmac.h"
#include "safe-memset.h"
void hmac_init(struct hmac_context *_ctx, const unsigned char *key,
size_t key_len, const struct hash_method *meth)
{
struct hmac_context_priv *ctx = &_ctx->u.priv;
int i;
unsigned char k_ipad[64];
unsigned char k_opad[64];
unsigned char hashedkey[meth->digest_size];
i_assert(meth->context_size <= HMAC_MAX_CONTEXT_SIZE);
ctx->hash = meth;
if (key_len > 64) {
meth->init(ctx->ctx);
meth->loop(ctx->ctx, key, key_len);
meth->result(ctx->ctx, hashedkey);
key = hashedkey;
key_len = meth->digest_size;
}
memcpy(k_ipad, key, key_len);
memset(k_ipad + key_len, 0, 64 - key_len);
memcpy(k_opad, k_ipad, 64);
for (i = 0; i < 64; i++) {
k_ipad[i] ^= 0x36;
k_opad[i] ^= 0x5c;
}
meth->init(ctx->ctx);
meth->loop(ctx->ctx, k_ipad, 64);
meth->init(ctx->ctxo);
meth->loop(ctx->ctxo, k_opad, 64);
safe_memset(k_ipad, 0, 64);
safe_memset(k_opad, 0, 64);
}
void hmac_final(struct hmac_context *_ctx, unsigned char *digest)
{
struct hmac_context_priv *ctx = &_ctx->u.priv;
ctx->hash->result(ctx->ctx, digest);
ctx->hash->loop(ctx->ctxo, digest, ctx->hash->digest_size);
ctx->hash->result(ctx->ctxo, digest);
}
|