hmac.c revision 280304 
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#ifdef OPENSSL_FIPS
65# include <openssl/fips.h>
66#endif
67
68int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
69                 const EVP_MD *md, ENGINE *impl)
70{
71    int i, j, reset = 0;
72    unsigned char pad[HMAC_MAX_MD_CBLOCK];
73
74#ifdef OPENSSL_FIPS
75    if (FIPS_mode()) {
76        /* If we have an ENGINE need to allow non FIPS */
77        if ((impl || ctx->i_ctx.engine)
78            && !(ctx->i_ctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)) {
79            EVPerr(EVP_F_HMAC_INIT_EX, EVP_R_DISABLED_FOR_FIPS);
80            return 0;
81        }
82        /*
83         * Other algorithm blocking will be done in FIPS_cmac_init, via
84         * FIPS_hmac_init_ex().
85         */
86        if (!impl && !ctx->i_ctx.engine)
87            return FIPS_hmac_init_ex(ctx, key, len, md, NULL);
88    }
89#endif
90
91    if (md != NULL) {
92        reset = 1;
93        ctx->md = md;
94    } else
95        md = ctx->md;
96
97    if (key != NULL) {
98        reset = 1;
99        j = EVP_MD_block_size(md);
100        OPENSSL_assert(j <= (int)sizeof(ctx->key));
101        if (j < len) {
102            if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
103                goto err;
104            if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
105                goto err;
106            if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
107                                    &ctx->key_length))
108                goto err;
109        } else {
110            OPENSSL_assert(len >= 0 && len <= (int)sizeof(ctx->key));
111            memcpy(ctx->key, key, len);
112            ctx->key_length = len;
113        }
114        if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
115            memset(&ctx->key[ctx->key_length], 0,
116                   HMAC_MAX_MD_CBLOCK - ctx->key_length);
117    }
118
119    if (reset) {
120        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
121            pad[i] = 0x36 ^ ctx->key[i];
122        if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
123            goto err;
124        if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md)))
125            goto err;
126
127        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
128            pad[i] = 0x5c ^ ctx->key[i];
129        if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
130            goto err;
131        if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md)))
132            goto err;
133    }
134    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
135        goto err;
136    return 1;
137 err:
138    return 0;
139}
140
141int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
142{
143    if (key && md)
144        HMAC_CTX_init(ctx);
145    return HMAC_Init_ex(ctx, key, len, md, NULL);
146}
147
148int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
149{
150#ifdef OPENSSL_FIPS
151    if (FIPS_mode() && !ctx->i_ctx.engine)
152        return FIPS_hmac_update(ctx, data, len);
153#endif
154    return EVP_DigestUpdate(&ctx->md_ctx, data, len);
155}
156
157int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
158{
159    unsigned int i;
160    unsigned char buf[EVP_MAX_MD_SIZE];
161#ifdef OPENSSL_FIPS
162    if (FIPS_mode() && !ctx->i_ctx.engine)
163        return FIPS_hmac_final(ctx, md, len);
164#endif
165
166    if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
167        goto err;
168    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
169        goto err;
170    if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
171        goto err;
172    if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
173        goto err;
174    return 1;
175 err:
176    return 0;
177}
178
179void HMAC_CTX_init(HMAC_CTX *ctx)
180{
181    EVP_MD_CTX_init(&ctx->i_ctx);
182    EVP_MD_CTX_init(&ctx->o_ctx);
183    EVP_MD_CTX_init(&ctx->md_ctx);
184}
185
186int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
187{
188    if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx))
189        goto err;
190    if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx))
191        goto err;
192    if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx))
193        goto err;
194    memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
195    dctx->key_length = sctx->key_length;
196    dctx->md = sctx->md;
197    return 1;
198 err:
199    return 0;
200}
201
202void HMAC_CTX_cleanup(HMAC_CTX *ctx)
203{
204#ifdef OPENSSL_FIPS
205    if (FIPS_mode() && !ctx->i_ctx.engine) {
206        FIPS_hmac_ctx_cleanup(ctx);
207        return;
208    }
209#endif
210    EVP_MD_CTX_cleanup(&ctx->i_ctx);
211    EVP_MD_CTX_cleanup(&ctx->o_ctx);
212    EVP_MD_CTX_cleanup(&ctx->md_ctx);
213    memset(ctx, 0, sizeof *ctx);
214}
215
216unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
217                    const unsigned char *d, size_t n, unsigned char *md,
218                    unsigned int *md_len)
219{
220    HMAC_CTX c;
221    static unsigned char m[EVP_MAX_MD_SIZE];
222
223    if (md == NULL)
224        md = m;
225    HMAC_CTX_init(&c);
226    if (!HMAC_Init(&c, key, key_len, evp_md))
227        goto err;
228    if (!HMAC_Update(&c, d, n))
229        goto err;
230    if (!HMAC_Final(&c, md, md_len))
231        goto err;
232    HMAC_CTX_cleanup(&c);
233    return md;
234 err:
235    return NULL;
236}
237
238void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
239{
240    EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
241    EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
242    EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
243}
244