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Commit | Line | Data |
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0f113f3e | 1 | /* |
33388b44 | 2 | * Copyright 2010-2020 The OpenSSL Project Authors. All Rights Reserved. |
8c968e03 | 3 | * |
8de396f8 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
4f22f405 RS |
5 | * this file except in compliance with the License. You can obtain a copy |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
8c968e03 DSH |
8 | */ |
9 | ||
a6d572e6 P |
10 | /* |
11 | * CMAC low level APIs are deprecated for public use, but still ok for internal | |
12 | * use. | |
13 | */ | |
14 | #include "internal/deprecated.h" | |
15 | ||
8c968e03 DSH |
16 | #include <stdio.h> |
17 | #include <stdlib.h> | |
18 | #include <string.h> | |
b39fc560 | 19 | #include "internal/cryptlib.h" |
8c968e03 | 20 | #include <openssl/cmac.h> |
7de2b9c4 | 21 | #include <openssl/err.h> |
8c968e03 | 22 | |
0f113f3e MC |
23 | struct CMAC_CTX_st { |
24 | /* Cipher context to use */ | |
846ec07d | 25 | EVP_CIPHER_CTX *cctx; |
0f113f3e MC |
26 | /* Keys k1 and k2 */ |
27 | unsigned char k1[EVP_MAX_BLOCK_LENGTH]; | |
28 | unsigned char k2[EVP_MAX_BLOCK_LENGTH]; | |
29 | /* Temporary block */ | |
30 | unsigned char tbl[EVP_MAX_BLOCK_LENGTH]; | |
31 | /* Last (possibly partial) block */ | |
32 | unsigned char last_block[EVP_MAX_BLOCK_LENGTH]; | |
33 | /* Number of bytes in last block: -1 means context not initialised */ | |
34 | int nlast_block; | |
35 | }; | |
8c968e03 DSH |
36 | |
37 | /* Make temporary keys K1 and K2 */ | |
38 | ||
03cf7e78 | 39 | static void make_kn(unsigned char *k1, const unsigned char *l, int bl) |
0f113f3e MC |
40 | { |
41 | int i; | |
42 | unsigned char c = l[0], carry = c >> 7, cnext; | |
03cf7e78 | 43 | |
0f113f3e MC |
44 | /* Shift block to left, including carry */ |
45 | for (i = 0; i < bl - 1; i++, c = cnext) | |
46 | k1[i] = (c << 1) | ((cnext = l[i + 1]) >> 7); | |
03cf7e78 | 47 | |
0f113f3e MC |
48 | /* If MSB set fixup with R */ |
49 | k1[i] = (c << 1) ^ ((0 - carry) & (bl == 16 ? 0x87 : 0x1b)); | |
50 | } | |
8c968e03 DSH |
51 | |
52 | CMAC_CTX *CMAC_CTX_new(void) | |
0f113f3e MC |
53 | { |
54 | CMAC_CTX *ctx; | |
b4faea50 | 55 | |
7de2b9c4 RS |
56 | if ((ctx = OPENSSL_malloc(sizeof(*ctx))) == NULL) { |
57 | CRYPTOerr(CRYPTO_F_CMAC_CTX_NEW, ERR_R_MALLOC_FAILURE); | |
0f113f3e | 58 | return NULL; |
7de2b9c4 | 59 | } |
846ec07d RL |
60 | ctx->cctx = EVP_CIPHER_CTX_new(); |
61 | if (ctx->cctx == NULL) { | |
62 | OPENSSL_free(ctx); | |
63 | return NULL; | |
64 | } | |
0f113f3e MC |
65 | ctx->nlast_block = -1; |
66 | return ctx; | |
67 | } | |
8c968e03 DSH |
68 | |
69 | void CMAC_CTX_cleanup(CMAC_CTX *ctx) | |
0f113f3e | 70 | { |
15d95dd7 | 71 | EVP_CIPHER_CTX_reset(ctx->cctx); |
0f113f3e MC |
72 | OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH); |
73 | OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH); | |
74 | OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH); | |
75 | OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH); | |
76 | ctx->nlast_block = -1; | |
77 | } | |
8c968e03 DSH |
78 | |
79 | EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx) | |
0f113f3e | 80 | { |
846ec07d | 81 | return ctx->cctx; |
0f113f3e | 82 | } |
8c968e03 DSH |
83 | |
84 | void CMAC_CTX_free(CMAC_CTX *ctx) | |
0f113f3e | 85 | { |
efa7dd64 RS |
86 | if (!ctx) |
87 | return; | |
0f113f3e | 88 | CMAC_CTX_cleanup(ctx); |
5c6c4c5c | 89 | EVP_CIPHER_CTX_free(ctx->cctx); |
0f113f3e MC |
90 | OPENSSL_free(ctx); |
91 | } | |
8c968e03 | 92 | |
c8ef656d | 93 | int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in) |
0f113f3e MC |
94 | { |
95 | int bl; | |
d5f85429 | 96 | |
0f113f3e MC |
97 | if (in->nlast_block == -1) |
98 | return 0; | |
d5f85429 RL |
99 | if ((bl = EVP_CIPHER_CTX_block_size(in->cctx)) < 0) |
100 | return 0; | |
846ec07d | 101 | if (!EVP_CIPHER_CTX_copy(out->cctx, in->cctx)) |
0f113f3e | 102 | return 0; |
0f113f3e MC |
103 | memcpy(out->k1, in->k1, bl); |
104 | memcpy(out->k2, in->k2, bl); | |
105 | memcpy(out->tbl, in->tbl, bl); | |
106 | memcpy(out->last_block, in->last_block, bl); | |
107 | out->nlast_block = in->nlast_block; | |
108 | return 1; | |
109 | } | |
c8ef656d | 110 | |
0f113f3e MC |
111 | int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen, |
112 | const EVP_CIPHER *cipher, ENGINE *impl) | |
113 | { | |
114 | static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = { 0 }; | |
d5f85429 | 115 | |
0f113f3e MC |
116 | /* All zeros means restart */ |
117 | if (!key && !cipher && !impl && keylen == 0) { | |
118 | /* Not initialised */ | |
119 | if (ctx->nlast_block == -1) | |
120 | return 0; | |
846ec07d | 121 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e | 122 | return 0; |
846ec07d | 123 | memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(ctx->cctx)); |
0f113f3e MC |
124 | ctx->nlast_block = 0; |
125 | return 1; | |
126 | } | |
0d4fb843 | 127 | /* Initialise context */ |
b896d943 MC |
128 | if (cipher != NULL) { |
129 | /* Ensure we can't use this ctx until we also have a key */ | |
130 | ctx->nlast_block = -1; | |
131 | if (!EVP_EncryptInit_ex(ctx->cctx, cipher, impl, NULL, NULL)) | |
132 | return 0; | |
133 | } | |
0f113f3e | 134 | /* Non-NULL key means initialisation complete */ |
b896d943 | 135 | if (key != NULL) { |
0f113f3e | 136 | int bl; |
d5f85429 | 137 | |
b896d943 MC |
138 | /* If anything fails then ensure we can't use this ctx */ |
139 | ctx->nlast_block = -1; | |
846ec07d | 140 | if (!EVP_CIPHER_CTX_cipher(ctx->cctx)) |
0f113f3e | 141 | return 0; |
846ec07d | 142 | if (!EVP_CIPHER_CTX_set_key_length(ctx->cctx, keylen)) |
0f113f3e | 143 | return 0; |
846ec07d | 144 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, key, zero_iv)) |
0f113f3e | 145 | return 0; |
d5f85429 RL |
146 | if ((bl = EVP_CIPHER_CTX_block_size(ctx->cctx)) < 0) |
147 | return 0; | |
846ec07d | 148 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, zero_iv, bl)) |
0f113f3e MC |
149 | return 0; |
150 | make_kn(ctx->k1, ctx->tbl, bl); | |
151 | make_kn(ctx->k2, ctx->k1, bl); | |
152 | OPENSSL_cleanse(ctx->tbl, bl); | |
153 | /* Reset context again ready for first data block */ | |
846ec07d | 154 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e MC |
155 | return 0; |
156 | /* Zero tbl so resume works */ | |
157 | memset(ctx->tbl, 0, bl); | |
158 | ctx->nlast_block = 0; | |
159 | } | |
160 | return 1; | |
161 | } | |
8c968e03 DSH |
162 | |
163 | int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen) | |
0f113f3e MC |
164 | { |
165 | const unsigned char *data = in; | |
d5f85429 RL |
166 | int bl; |
167 | ||
0f113f3e MC |
168 | if (ctx->nlast_block == -1) |
169 | return 0; | |
170 | if (dlen == 0) | |
171 | return 1; | |
d5f85429 RL |
172 | if ((bl = EVP_CIPHER_CTX_block_size(ctx->cctx)) < 0) |
173 | return 0; | |
0f113f3e MC |
174 | /* Copy into partial block if we need to */ |
175 | if (ctx->nlast_block > 0) { | |
176 | size_t nleft; | |
d5f85429 | 177 | |
0f113f3e MC |
178 | nleft = bl - ctx->nlast_block; |
179 | if (dlen < nleft) | |
180 | nleft = dlen; | |
181 | memcpy(ctx->last_block + ctx->nlast_block, data, nleft); | |
182 | dlen -= nleft; | |
183 | ctx->nlast_block += nleft; | |
184 | /* If no more to process return */ | |
185 | if (dlen == 0) | |
186 | return 1; | |
187 | data += nleft; | |
188 | /* Else not final block so encrypt it */ | |
846ec07d | 189 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, ctx->last_block, bl)) |
0f113f3e MC |
190 | return 0; |
191 | } | |
192 | /* Encrypt all but one of the complete blocks left */ | |
d5f85429 | 193 | while (dlen > (size_t)bl) { |
846ec07d | 194 | if (!EVP_Cipher(ctx->cctx, ctx->tbl, data, bl)) |
0f113f3e MC |
195 | return 0; |
196 | dlen -= bl; | |
197 | data += bl; | |
198 | } | |
199 | /* Copy any data left to last block buffer */ | |
200 | memcpy(ctx->last_block, data, dlen); | |
201 | ctx->nlast_block = dlen; | |
202 | return 1; | |
8c968e03 | 203 | |
0f113f3e | 204 | } |
8c968e03 | 205 | |
c8ef656d | 206 | int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen) |
0f113f3e MC |
207 | { |
208 | int i, bl, lb; | |
d5f85429 | 209 | |
0f113f3e MC |
210 | if (ctx->nlast_block == -1) |
211 | return 0; | |
d5f85429 RL |
212 | if ((bl = EVP_CIPHER_CTX_block_size(ctx->cctx)) < 0) |
213 | return 0; | |
f6dead1b RH |
214 | if (poutlen != NULL) |
215 | *poutlen = (size_t)bl; | |
0f113f3e MC |
216 | if (!out) |
217 | return 1; | |
218 | lb = ctx->nlast_block; | |
219 | /* Is last block complete? */ | |
220 | if (lb == bl) { | |
221 | for (i = 0; i < bl; i++) | |
222 | out[i] = ctx->last_block[i] ^ ctx->k1[i]; | |
223 | } else { | |
224 | ctx->last_block[lb] = 0x80; | |
225 | if (bl - lb > 1) | |
226 | memset(ctx->last_block + lb + 1, 0, bl - lb - 1); | |
227 | for (i = 0; i < bl; i++) | |
228 | out[i] = ctx->last_block[i] ^ ctx->k2[i]; | |
229 | } | |
846ec07d | 230 | if (!EVP_Cipher(ctx->cctx, out, out, bl)) { |
0f113f3e MC |
231 | OPENSSL_cleanse(out, bl); |
232 | return 0; | |
233 | } | |
234 | return 1; | |
235 | } | |
c8ef656d DSH |
236 | |
237 | int CMAC_resume(CMAC_CTX *ctx) | |
0f113f3e MC |
238 | { |
239 | if (ctx->nlast_block == -1) | |
240 | return 0; | |
241 | /* | |
0d4fb843 | 242 | * The buffer "tbl" contains the last fully encrypted block which is the |
0f113f3e | 243 | * last IV (or all zeroes if no last encrypted block). The last block has |
0d4fb843 | 244 | * not been modified since CMAC_final(). So reinitialising using the last |
0f113f3e MC |
245 | * decrypted block will allow CMAC to continue after calling |
246 | * CMAC_Final(). | |
247 | */ | |
512fdfdf | 248 | return EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, ctx->tbl); |
0f113f3e | 249 | } |