hmac.c revision 296465 
1/* crypto/hmac/hmac.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include "cryptlib.h"
62#include <openssl/hmac.h>
63
64#ifndef OPENSSL_FIPS
65
66void HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
67                  const EVP_MD *md, ENGINE *impl)
68{
69    int i, j, reset = 0;
70    unsigned char pad[HMAC_MAX_MD_CBLOCK];
71
72    if (md != NULL) {
73        reset = 1;
74        ctx->md = md;
75    } else
76        md = ctx->md;
77
78    if (key != NULL) {
79        reset = 1;
80        j = EVP_MD_block_size(md);
81        OPENSSL_assert(j <= (int)sizeof(ctx->key));
82        if (j < len) {
83            EVP_DigestInit_ex(&ctx->md_ctx, md, impl);
84            EVP_DigestUpdate(&ctx->md_ctx, key, len);
85            EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key, &ctx->key_length);
86        } else {
87            OPENSSL_assert(len >= 0 && len <= (int)sizeof(ctx->key));
88            memcpy(ctx->key, key, len);
89            ctx->key_length = len;
90        }
91        if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
92            memset(&ctx->key[ctx->key_length], 0,
93                   HMAC_MAX_MD_CBLOCK - ctx->key_length);
94    }
95
96    if (reset) {
97        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
98            pad[i] = 0x36 ^ ctx->key[i];
99        EVP_DigestInit_ex(&ctx->i_ctx, md, impl);
100        EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md));
101
102        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
103            pad[i] = 0x5c ^ ctx->key[i];
104        EVP_DigestInit_ex(&ctx->o_ctx, md, impl);
105        EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md));
106    }
107    EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx);
108}
109
110void HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
111{
112    if (key && md)
113        HMAC_CTX_init(ctx);
114    HMAC_Init_ex(ctx, key, len, md, NULL);
115}
116
117void HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
118{
119    EVP_DigestUpdate(&ctx->md_ctx, data, len);
120}
121
122void HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
123{
124    unsigned int i;
125    unsigned char buf[EVP_MAX_MD_SIZE];
126
127    EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i);
128    EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx);
129    EVP_DigestUpdate(&ctx->md_ctx, buf, i);
130    EVP_DigestFinal_ex(&ctx->md_ctx, md, len);
131}
132
133void HMAC_CTX_init(HMAC_CTX *ctx)
134{
135    EVP_MD_CTX_init(&ctx->i_ctx);
136    EVP_MD_CTX_init(&ctx->o_ctx);
137    EVP_MD_CTX_init(&ctx->md_ctx);
138}
139
140void HMAC_CTX_cleanup(HMAC_CTX *ctx)
141{
142    EVP_MD_CTX_cleanup(&ctx->i_ctx);
143    EVP_MD_CTX_cleanup(&ctx->o_ctx);
144    EVP_MD_CTX_cleanup(&ctx->md_ctx);
145    memset(ctx, 0, sizeof *ctx);
146}
147
148unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
149                    const unsigned char *d, size_t n, unsigned char *md,
150                    unsigned int *md_len)
151{
152    HMAC_CTX c;
153    static unsigned char m[EVP_MAX_MD_SIZE];
154
155    if (md == NULL)
156        md = m;
157    HMAC_CTX_init(&c);
158    HMAC_Init(&c, key, key_len, evp_md);
159    HMAC_Update(&c, d, n);
160    HMAC_Final(&c, md, md_len);
161    HMAC_CTX_cleanup(&c);
162    return (md);
163}
164
165void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
166{
167    EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
168    EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
169    EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
170}
171
172#endif
173