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8c968e03 | 1 | /* crypto/cmac/cmac.c */ |
0f113f3e MC |
2 | /* |
3 | * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL | |
8c968e03 DSH |
4 | * project. |
5 | */ | |
6 | /* ==================================================================== | |
7 | * Copyright (c) 2010 The OpenSSL Project. All rights reserved. | |
8 | * | |
9 | * Redistribution and use in source and binary forms, with or without | |
10 | * modification, are permitted provided that the following conditions | |
11 | * are met: | |
12 | * | |
13 | * 1. Redistributions of source code must retain the above copyright | |
0f113f3e | 14 | * notice, this list of conditions and the following disclaimer. |
8c968e03 DSH |
15 | * |
16 | * 2. Redistributions in binary form must reproduce the above copyright | |
17 | * notice, this list of conditions and the following disclaimer in | |
18 | * the documentation and/or other materials provided with the | |
19 | * distribution. | |
20 | * | |
21 | * 3. All advertising materials mentioning features or use of this | |
22 | * software must display the following acknowledgment: | |
23 | * "This product includes software developed by the OpenSSL Project | |
24 | * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" | |
25 | * | |
26 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
27 | * endorse or promote products derived from this software without | |
28 | * prior written permission. For written permission, please contact | |
29 | * licensing@OpenSSL.org. | |
30 | * | |
31 | * 5. Products derived from this software may not be called "OpenSSL" | |
32 | * nor may "OpenSSL" appear in their names without prior written | |
33 | * permission of the OpenSSL Project. | |
34 | * | |
35 | * 6. Redistributions of any form whatsoever must retain the following | |
36 | * acknowledgment: | |
37 | * "This product includes software developed by the OpenSSL Project | |
38 | * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" | |
39 | * | |
40 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
41 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
42 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
43 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
44 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
45 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
46 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
47 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
49 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
50 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
51 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
52 | * ==================================================================== | |
53 | */ | |
54 | ||
55 | #include <stdio.h> | |
56 | #include <stdlib.h> | |
57 | #include <string.h> | |
b39fc560 | 58 | #include "internal/cryptlib.h" |
8c968e03 DSH |
59 | #include <openssl/cmac.h> |
60 | ||
0f113f3e MC |
61 | struct CMAC_CTX_st { |
62 | /* Cipher context to use */ | |
846ec07d | 63 | EVP_CIPHER_CTX *cctx; |
0f113f3e MC |
64 | /* Keys k1 and k2 */ |
65 | unsigned char k1[EVP_MAX_BLOCK_LENGTH]; | |
66 | unsigned char k2[EVP_MAX_BLOCK_LENGTH]; | |
67 | /* Temporary block */ | |
68 | unsigned char tbl[EVP_MAX_BLOCK_LENGTH]; | |
69 | /* Last (possibly partial) block */ | |
70 | unsigned char last_block[EVP_MAX_BLOCK_LENGTH]; | |
71 | /* Number of bytes in last block: -1 means context not initialised */ | |
72 | int nlast_block; | |
73 | }; | |
8c968e03 DSH |
74 | |
75 | /* Make temporary keys K1 and K2 */ | |
76 | ||
03cf7e78 | 77 | static void make_kn(unsigned char *k1, const unsigned char *l, int bl) |
0f113f3e MC |
78 | { |
79 | int i; | |
80 | unsigned char c = l[0], carry = c >> 7, cnext; | |
03cf7e78 | 81 | |
0f113f3e MC |
82 | /* Shift block to left, including carry */ |
83 | for (i = 0; i < bl - 1; i++, c = cnext) | |
84 | k1[i] = (c << 1) | ((cnext = l[i + 1]) >> 7); | |
03cf7e78 | 85 | |
0f113f3e MC |
86 | /* If MSB set fixup with R */ |
87 | k1[i] = (c << 1) ^ ((0 - carry) & (bl == 16 ? 0x87 : 0x1b)); | |
88 | } | |
8c968e03 DSH |
89 | |
90 | CMAC_CTX *CMAC_CTX_new(void) | |
0f113f3e MC |
91 | { |
92 | CMAC_CTX *ctx; | |
b4faea50 RS |
93 | |
94 | ctx = OPENSSL_malloc(sizeof(*ctx)); | |
90945fa3 | 95 | if (ctx == NULL) |
0f113f3e | 96 | return NULL; |
846ec07d RL |
97 | ctx->cctx = EVP_CIPHER_CTX_new(); |
98 | if (ctx->cctx == NULL) { | |
99 | OPENSSL_free(ctx); | |
100 | return NULL; | |
101 | } | |
0f113f3e MC |
102 | ctx->nlast_block = -1; |
103 | return ctx; | |
104 | } | |
8c968e03 DSH |
105 | |
106 | void CMAC_CTX_cleanup(CMAC_CTX *ctx) | |
0f113f3e | 107 | { |
846ec07d | 108 | EVP_CIPHER_CTX_free(ctx->cctx); |
0f113f3e MC |
109 | OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH); |
110 | OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH); | |
111 | OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH); | |
112 | OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH); | |
113 | ctx->nlast_block = -1; | |
114 | } | |
8c968e03 DSH |
115 | |
116 | EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx) | |
0f113f3e | 117 | { |
846ec07d | 118 | return ctx->cctx; |
0f113f3e | 119 | } |
8c968e03 DSH |
120 | |
121 | void CMAC_CTX_free(CMAC_CTX *ctx) | |
0f113f3e | 122 | { |
efa7dd64 RS |
123 | if (!ctx) |
124 | return; | |
0f113f3e MC |
125 | CMAC_CTX_cleanup(ctx); |
126 | OPENSSL_free(ctx); | |
127 | } | |
8c968e03 | 128 | |
c8ef656d | 129 | int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in) |
0f113f3e MC |
130 | { |
131 | int bl; | |
132 | if (in->nlast_block == -1) | |
133 | return 0; | |
846ec07d | 134 | if (!EVP_CIPHER_CTX_copy(out->cctx, in->cctx)) |
0f113f3e | 135 | return 0; |
846ec07d | 136 | bl = EVP_CIPHER_CTX_block_size(in->cctx); |
0f113f3e MC |
137 | memcpy(out->k1, in->k1, bl); |
138 | memcpy(out->k2, in->k2, bl); | |
139 | memcpy(out->tbl, in->tbl, bl); | |
140 | memcpy(out->last_block, in->last_block, bl); | |
141 | out->nlast_block = in->nlast_block; | |
142 | return 1; | |
143 | } | |
c8ef656d | 144 | |
0f113f3e MC |
145 | int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen, |
146 | const EVP_CIPHER *cipher, ENGINE *impl) | |
147 | { | |
148 | static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = { 0 }; | |
149 | /* All zeros means restart */ | |
150 | if (!key && !cipher && !impl && keylen == 0) { | |
151 | /* Not initialised */ | |
152 | if (ctx->nlast_block == -1) | |
153 | return 0; | |
846ec07d | 154 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e | 155 | return 0; |
846ec07d | 156 | memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(ctx->cctx)); |
0f113f3e MC |
157 | ctx->nlast_block = 0; |
158 | return 1; | |
159 | } | |
160 | /* Initialiase context */ | |
846ec07d | 161 | if (cipher && !EVP_EncryptInit_ex(ctx->cctx, cipher, impl, NULL, NULL)) |
0f113f3e MC |
162 | return 0; |
163 | /* Non-NULL key means initialisation complete */ | |
164 | if (key) { | |
165 | int bl; | |
846ec07d | 166 | if (!EVP_CIPHER_CTX_cipher(ctx->cctx)) |
0f113f3e | 167 | return 0; |
846ec07d | 168 | if (!EVP_CIPHER_CTX_set_key_length(ctx->cctx, keylen)) |
0f113f3e | 169 | return 0; |
846ec07d | 170 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, key, zero_iv)) |
0f113f3e | 171 | return 0; |
846ec07d RL |
172 | bl = EVP_CIPHER_CTX_block_size(ctx->cctx); |
173 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, zero_iv, bl)) | |
0f113f3e MC |
174 | return 0; |
175 | make_kn(ctx->k1, ctx->tbl, bl); | |
176 | make_kn(ctx->k2, ctx->k1, bl); | |
177 | OPENSSL_cleanse(ctx->tbl, bl); | |
178 | /* Reset context again ready for first data block */ | |
846ec07d | 179 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e MC |
180 | return 0; |
181 | /* Zero tbl so resume works */ | |
182 | memset(ctx->tbl, 0, bl); | |
183 | ctx->nlast_block = 0; | |
184 | } | |
185 | return 1; | |
186 | } | |
8c968e03 DSH |
187 | |
188 | int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen) | |
0f113f3e MC |
189 | { |
190 | const unsigned char *data = in; | |
191 | size_t bl; | |
192 | if (ctx->nlast_block == -1) | |
193 | return 0; | |
194 | if (dlen == 0) | |
195 | return 1; | |
846ec07d | 196 | bl = EVP_CIPHER_CTX_block_size(ctx->cctx); |
0f113f3e MC |
197 | /* Copy into partial block if we need to */ |
198 | if (ctx->nlast_block > 0) { | |
199 | size_t nleft; | |
200 | nleft = bl - ctx->nlast_block; | |
201 | if (dlen < nleft) | |
202 | nleft = dlen; | |
203 | memcpy(ctx->last_block + ctx->nlast_block, data, nleft); | |
204 | dlen -= nleft; | |
205 | ctx->nlast_block += nleft; | |
206 | /* If no more to process return */ | |
207 | if (dlen == 0) | |
208 | return 1; | |
209 | data += nleft; | |
210 | /* Else not final block so encrypt it */ | |
846ec07d | 211 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, ctx->last_block, bl)) |
0f113f3e MC |
212 | return 0; |
213 | } | |
214 | /* Encrypt all but one of the complete blocks left */ | |
215 | while (dlen > bl) { | |
846ec07d | 216 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, data, bl)) |
0f113f3e MC |
217 | return 0; |
218 | dlen -= bl; | |
219 | data += bl; | |
220 | } | |
221 | /* Copy any data left to last block buffer */ | |
222 | memcpy(ctx->last_block, data, dlen); | |
223 | ctx->nlast_block = dlen; | |
224 | return 1; | |
8c968e03 | 225 | |
0f113f3e | 226 | } |
8c968e03 | 227 | |
c8ef656d | 228 | int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen) |
0f113f3e MC |
229 | { |
230 | int i, bl, lb; | |
231 | if (ctx->nlast_block == -1) | |
232 | return 0; | |
846ec07d | 233 | bl = EVP_CIPHER_CTX_block_size(ctx->cctx); |
0f113f3e MC |
234 | *poutlen = (size_t)bl; |
235 | if (!out) | |
236 | return 1; | |
237 | lb = ctx->nlast_block; | |
238 | /* Is last block complete? */ | |
239 | if (lb == bl) { | |
240 | for (i = 0; i < bl; i++) | |
241 | out[i] = ctx->last_block[i] ^ ctx->k1[i]; | |
242 | } else { | |
243 | ctx->last_block[lb] = 0x80; | |
244 | if (bl - lb > 1) | |
245 | memset(ctx->last_block + lb + 1, 0, bl - lb - 1); | |
246 | for (i = 0; i < bl; i++) | |
247 | out[i] = ctx->last_block[i] ^ ctx->k2[i]; | |
248 | } | |
846ec07d | 249 | if (!EVP_Cipher(ctx->cctx, out, out, bl)) { |
0f113f3e MC |
250 | OPENSSL_cleanse(out, bl); |
251 | return 0; | |
252 | } | |
253 | return 1; | |
254 | } | |
c8ef656d DSH |
255 | |
256 | int CMAC_resume(CMAC_CTX *ctx) | |
0f113f3e MC |
257 | { |
258 | if (ctx->nlast_block == -1) | |
259 | return 0; | |
260 | /* | |
261 | * The buffer "tbl" containes the last fully encrypted block which is the | |
262 | * last IV (or all zeroes if no last encrypted block). The last block has | |
263 | * not been modified since CMAC_final(). So reinitliasing using the last | |
264 | * decrypted block will allow CMAC to continue after calling | |
265 | * CMAC_Final(). | |
266 | */ | |
846ec07d | 267 | return M_EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, ctx->tbl); |
0f113f3e | 268 | } |