hmac.c revision 306195 
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 switch to approved implementation if possible */
76    if (FIPS_mode()) {
77        const EVP_MD *fipsmd;
78        if (md) {
79            fipsmd = FIPS_get_digestbynid(EVP_MD_type(md));
80            if (fipsmd)
81                md = fipsmd;
82        }
83    }
84
85    if (FIPS_mode()) {
86        /* If we have an ENGINE need to allow non FIPS */
87        if ((impl || ctx->i_ctx.engine)
88            && !(ctx->i_ctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)) {
89            EVPerr(EVP_F_HMAC_INIT_EX, EVP_R_DISABLED_FOR_FIPS);
90            return 0;
91        }
92        /*
93         * Other algorithm blocking will be done in FIPS_cmac_init, via
94         * FIPS_hmac_init_ex().
95         */
96        if (!impl && !ctx->i_ctx.engine)
97            return FIPS_hmac_init_ex(ctx, key, len, md, NULL);
98    }
99#endif
100    /* If we are changing MD then we must have a key */
101    if (md != NULL && md != ctx->md && (key == NULL || len < 0))
102        return 0;
103
104    if (md != NULL) {
105        reset = 1;
106        ctx->md = md;
107    } else if (ctx->md) {
108        md = ctx->md;
109    } else {
110        return 0;
111    }
112
113    if (key != NULL) {
114        reset = 1;
115        j = EVP_MD_block_size(md);
116        OPENSSL_assert(j <= (int)sizeof(ctx->key));
117        if (j < len) {
118            if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))
119                goto err;
120            if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))
121                goto err;
122            if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,
123                                    &ctx->key_length))
124                goto err;
125        } else {
126            if (len < 0 || len > (int)sizeof(ctx->key))
127                return 0;
128            memcpy(ctx->key, key, len);
129            ctx->key_length = len;
130        }
131        if (ctx->key_length != HMAC_MAX_MD_CBLOCK)
132            memset(&ctx->key[ctx->key_length], 0,
133                   HMAC_MAX_MD_CBLOCK - ctx->key_length);
134    }
135
136    if (reset) {
137        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
138            pad[i] = 0x36 ^ ctx->key[i];
139        if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))
140            goto err;
141        if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md)))
142            goto err;
143
144        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)
145            pad[i] = 0x5c ^ ctx->key[i];
146        if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))
147            goto err;
148        if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md)))
149            goto err;
150    }
151    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))
152        goto err;
153    return 1;
154 err:
155    return 0;
156}
157
158int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)
159{
160    if (key && md)
161        HMAC_CTX_init(ctx);
162    return HMAC_Init_ex(ctx, key, len, md, NULL);
163}
164
165int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
166{
167#ifdef OPENSSL_FIPS
168    if (FIPS_mode() && !ctx->i_ctx.engine)
169        return FIPS_hmac_update(ctx, data, len);
170#endif
171    if (!ctx->md)
172        return 0;
173
174    return EVP_DigestUpdate(&ctx->md_ctx, data, len);
175}
176
177int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
178{
179    unsigned int i;
180    unsigned char buf[EVP_MAX_MD_SIZE];
181#ifdef OPENSSL_FIPS
182    if (FIPS_mode() && !ctx->i_ctx.engine)
183        return FIPS_hmac_final(ctx, md, len);
184#endif
185
186    if (!ctx->md)
187        goto err;
188
189    if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))
190        goto err;
191    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))
192        goto err;
193    if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))
194        goto err;
195    if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))
196        goto err;
197    return 1;
198 err:
199    return 0;
200}
201
202void HMAC_CTX_init(HMAC_CTX *ctx)
203{
204    EVP_MD_CTX_init(&ctx->i_ctx);
205    EVP_MD_CTX_init(&ctx->o_ctx);
206    EVP_MD_CTX_init(&ctx->md_ctx);
207    ctx->md = NULL;
208}
209
210int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)
211{
212    if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx))
213        goto err;
214    if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx))
215        goto err;
216    if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx))
217        goto err;
218    memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);
219    dctx->key_length = sctx->key_length;
220    dctx->md = sctx->md;
221    return 1;
222 err:
223    return 0;
224}
225
226void HMAC_CTX_cleanup(HMAC_CTX *ctx)
227{
228#ifdef OPENSSL_FIPS
229    if (FIPS_mode() && !ctx->i_ctx.engine) {
230        FIPS_hmac_ctx_cleanup(ctx);
231        return;
232    }
233#endif
234    EVP_MD_CTX_cleanup(&ctx->i_ctx);
235    EVP_MD_CTX_cleanup(&ctx->o_ctx);
236    EVP_MD_CTX_cleanup(&ctx->md_ctx);
237    OPENSSL_cleanse(ctx, sizeof *ctx);
238}
239
240unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
241                    const unsigned char *d, size_t n, unsigned char *md,
242                    unsigned int *md_len)
243{
244    HMAC_CTX c;
245    static unsigned char m[EVP_MAX_MD_SIZE];
246
247    if (md == NULL)
248        md = m;
249    HMAC_CTX_init(&c);
250    if (!HMAC_Init(&c, key, key_len, evp_md))
251        goto err;
252    if (!HMAC_Update(&c, d, n))
253        goto err;
254    if (!HMAC_Final(&c, md, md_len))
255        goto err;
256    HMAC_CTX_cleanup(&c);
257    return md;
258 err:
259    HMAC_CTX_cleanup(&c);
260    return NULL;
261}
262
263void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
264{
265    EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
266    EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
267    EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
268}
269