aboutsummaryrefslogtreecommitdiff
path: root/openssl/crypto/cmac/cmac.c
blob: 774e6dc919050dc46d668cebf5514ca14a39f1e3 (plain)
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
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
/* crypto/cmac/cmac.c */
/*
 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 2010 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cryptlib.h"
#include <openssl/cmac.h>

#ifdef OPENSSL_FIPS
# include <openssl/fips.h>
#endif

struct CMAC_CTX_st {
    /* Cipher context to use */
    EVP_CIPHER_CTX cctx;
    /* Keys k1 and k2 */
    unsigned char k1[EVP_MAX_BLOCK_LENGTH];
    unsigned char k2[EVP_MAX_BLOCK_LENGTH];
    /* Temporary block */
    unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
    /* Last (possibly partial) block */
    unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
    /* Number of bytes in last block: -1 means context not initialised */
    int nlast_block;
};

/* Make temporary keys K1 and K2 */

static void make_kn(unsigned char *k1, unsigned char *l, int bl)
{
    int i;
    /* Shift block to left, including carry */
    for (i = 0; i < bl; i++) {
        k1[i] = l[i] << 1;
        if (i < bl - 1 && l[i + 1] & 0x80)
            k1[i] |= 1;
    }
    /* If MSB set fixup with R */
    if (l[0] & 0x80)
        k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
}

CMAC_CTX *CMAC_CTX_new(void)
{
    CMAC_CTX *ctx;
    ctx = OPENSSL_malloc(sizeof(CMAC_CTX));
    if (!ctx)
        return NULL;
    EVP_CIPHER_CTX_init(&ctx->cctx);
    ctx->nlast_block = -1;
    return ctx;
}

void CMAC_CTX_cleanup(CMAC_CTX *ctx)
{
#ifdef OPENSSL_FIPS
    if (FIPS_mode() && !ctx->cctx.engine) {
        FIPS_cmac_ctx_cleanup(ctx);
        return;
    }
#endif
    EVP_CIPHER_CTX_cleanup(&ctx->cctx);
    OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
    OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
    OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
    OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
    ctx->nlast_block = -1;
}

EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
{
    return &ctx->cctx;
}

void CMAC_CTX_free(CMAC_CTX *ctx)
{
    if (!ctx)
        return;
    CMAC_CTX_cleanup(ctx);
    OPENSSL_free(ctx);
}

int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
{
    int bl;
    if (in->nlast_block == -1)
        return 0;
    if (!EVP_CIPHER_CTX_copy(&out->cctx, &in->cctx))
        return 0;
    bl = EVP_CIPHER_CTX_block_size(&in->cctx);
    memcpy(out->k1, in->k1, bl);
    memcpy(out->k2, in->k2, bl);
    memcpy(out->tbl, in->tbl, bl);
    memcpy(out->last_block, in->last_block, bl);
    out->nlast_block = in->nlast_block;
    return 1;
}

int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
              const EVP_CIPHER *cipher, ENGINE *impl)
{
    static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
#ifdef OPENSSL_FIPS
    if (FIPS_mode()) {
        /* If we have an ENGINE need to allow non FIPS */
        if ((impl || ctx->cctx.engine)
            && !(ctx->cctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)) {
            EVPerr(EVP_F_CMAC_INIT, EVP_R_DISABLED_FOR_FIPS);
            return 0;
        }
        /*
         * Other algorithm blocking will be done in FIPS_cmac_init, via
         * FIPS_cipherinit().
         */
        if (!impl && !ctx->cctx.engine)
            return FIPS_cmac_init(ctx, key, keylen, cipher, NULL);
    }
#endif
    /* All zeros means restart */
    if (!key && !cipher && !impl && keylen == 0) {
        /* Not initialised */
        if (ctx->nlast_block == -1)
            return 0;
        if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
            return 0;
        memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(&ctx->cctx));
        ctx->nlast_block = 0;
        return 1;
    }
    /* Initialiase context */
    if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL))
        return 0;
    /* Non-NULL key means initialisation complete */
    if (key) {
        int bl;
        if (!EVP_CIPHER_CTX_cipher(&ctx->cctx))
            return 0;
        if (!EVP_CIPHER_CTX_set_key_length(&ctx->cctx, keylen))
            return 0;
        if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, key, zero_iv))
            return 0;
        bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
        if (!EVP_Cipher(&ctx->cctx, ctx->tbl, zero_iv, bl))
            return 0;
        make_kn(ctx->k1, ctx->tbl, bl);
        make_kn(ctx->k2, ctx->k1, bl);
        OPENSSL_cleanse(ctx->tbl, bl);
        /* Reset context again ready for first data block */
        if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
            return 0;
        /* Zero tbl so resume works */
        memset(ctx->tbl, 0, bl);
        ctx->nlast_block = 0;
    }
    return 1;
}

int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
{
    const unsigned char *data = in;
    size_t bl;
#ifdef OPENSSL_FIPS
    if (FIPS_mode() && !ctx->cctx.engine)
        return FIPS_cmac_update(ctx, in, dlen);
#endif
    if (ctx->nlast_block == -1)
        return 0;
    if (dlen == 0)
        return 1;
    bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
    /* Copy into partial block if we need to */
    if (ctx->nlast_block > 0) {
        size_t nleft;
        nleft = bl - ctx->nlast_block;
        if (dlen < nleft)
            nleft = dlen;
        memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
        dlen -= nleft;
        ctx->nlast_block += nleft;
        /* If no more to process return */
        if (dlen == 0)
            return 1;
        data += nleft;
        /* Else not final block so encrypt it */
        if (!EVP_Cipher(&ctx->cctx, ctx->tbl, ctx->last_block, bl))
            return 0;
    }
    /* Encrypt all but one of the complete blocks left */
    while (dlen > bl) {
        if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl))
            return 0;
        dlen -= bl;
        data += bl;
    }
    /* Copy any data left to last block buffer */
    memcpy(ctx->last_block, data, dlen);
    ctx->nlast_block = dlen;
    return 1;

}

int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
{
    int i, bl, lb;
#ifdef OPENSSL_FIPS
    if (FIPS_mode() && !ctx->cctx.engine)
        return FIPS_cmac_final(ctx, out, poutlen);
#endif
    if (ctx->nlast_block == -1)
        return 0;
    bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
    *poutlen = (size_t)bl;
    if (!out)
        return 1;
    lb = ctx->nlast_block;
    /* Is last block complete? */
    if (lb == bl) {
        for (i = 0; i < bl; i++)
            out[i] = ctx->last_block[i] ^ ctx->k1[i];
    } else {
        ctx->last_block[lb] = 0x80;
        if (bl - lb > 1)
            memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
        for (i = 0; i < bl; i++)
            out[i] = ctx->last_block[i] ^ ctx->k2[i];
    }
    if (!EVP_Cipher(&ctx->cctx, out, out, bl)) {
        OPENSSL_cleanse(out, bl);
        return 0;
    }
    return 1;
}

int CMAC_resume(CMAC_CTX *ctx)
{
    if (ctx->nlast_block == -1)
        return 0;
    /*
     * The buffer "tbl" containes the last fully encrypted block which is the
     * last IV (or all zeroes if no last encrypted block). The last block has
     * not been modified since CMAC_final(). So reinitliasing using the last
     * decrypted block will allow CMAC to continue after calling
     * CMAC_Final().
     */
    return EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, ctx->tbl);
}