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