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Commit | Line | Data |
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0f113f3e | 1 | /* |
da1c088f | 2 | * Copyright 2010-2023 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 | |
dc19f2f6 | 23 | #define LOCAL_BUF_SIZE 2048 |
0f113f3e MC |
24 | struct CMAC_CTX_st { |
25 | /* Cipher context to use */ | |
846ec07d | 26 | EVP_CIPHER_CTX *cctx; |
0f113f3e MC |
27 | /* Keys k1 and k2 */ |
28 | unsigned char k1[EVP_MAX_BLOCK_LENGTH]; | |
29 | unsigned char k2[EVP_MAX_BLOCK_LENGTH]; | |
30 | /* Temporary block */ | |
31 | unsigned char tbl[EVP_MAX_BLOCK_LENGTH]; | |
32 | /* Last (possibly partial) block */ | |
33 | unsigned char last_block[EVP_MAX_BLOCK_LENGTH]; | |
34 | /* Number of bytes in last block: -1 means context not initialised */ | |
35 | int nlast_block; | |
36 | }; | |
8c968e03 DSH |
37 | |
38 | /* Make temporary keys K1 and K2 */ | |
39 | ||
03cf7e78 | 40 | static void make_kn(unsigned char *k1, const unsigned char *l, int bl) |
0f113f3e MC |
41 | { |
42 | int i; | |
43 | unsigned char c = l[0], carry = c >> 7, cnext; | |
03cf7e78 | 44 | |
0f113f3e MC |
45 | /* Shift block to left, including carry */ |
46 | for (i = 0; i < bl - 1; i++, c = cnext) | |
47 | k1[i] = (c << 1) | ((cnext = l[i + 1]) >> 7); | |
03cf7e78 | 48 | |
0f113f3e MC |
49 | /* If MSB set fixup with R */ |
50 | k1[i] = (c << 1) ^ ((0 - carry) & (bl == 16 ? 0x87 : 0x1b)); | |
51 | } | |
8c968e03 DSH |
52 | |
53 | CMAC_CTX *CMAC_CTX_new(void) | |
0f113f3e MC |
54 | { |
55 | CMAC_CTX *ctx; | |
b4faea50 | 56 | |
e077455e | 57 | if ((ctx = OPENSSL_malloc(sizeof(*ctx))) == NULL) |
0f113f3e | 58 | return NULL; |
846ec07d RL |
59 | ctx->cctx = EVP_CIPHER_CTX_new(); |
60 | if (ctx->cctx == NULL) { | |
61 | OPENSSL_free(ctx); | |
62 | return NULL; | |
63 | } | |
0f113f3e MC |
64 | ctx->nlast_block = -1; |
65 | return ctx; | |
66 | } | |
8c968e03 DSH |
67 | |
68 | void CMAC_CTX_cleanup(CMAC_CTX *ctx) | |
0f113f3e | 69 | { |
15d95dd7 | 70 | EVP_CIPHER_CTX_reset(ctx->cctx); |
0f113f3e MC |
71 | OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH); |
72 | OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH); | |
73 | OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH); | |
74 | OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH); | |
75 | ctx->nlast_block = -1; | |
76 | } | |
8c968e03 DSH |
77 | |
78 | EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx) | |
0f113f3e | 79 | { |
846ec07d | 80 | return ctx->cctx; |
0f113f3e | 81 | } |
8c968e03 DSH |
82 | |
83 | void CMAC_CTX_free(CMAC_CTX *ctx) | |
0f113f3e | 84 | { |
efa7dd64 RS |
85 | if (!ctx) |
86 | return; | |
0f113f3e | 87 | CMAC_CTX_cleanup(ctx); |
5c6c4c5c | 88 | EVP_CIPHER_CTX_free(ctx->cctx); |
0f113f3e MC |
89 | OPENSSL_free(ctx); |
90 | } | |
8c968e03 | 91 | |
c8ef656d | 92 | int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in) |
0f113f3e MC |
93 | { |
94 | int bl; | |
d5f85429 | 95 | |
0f113f3e MC |
96 | if (in->nlast_block == -1) |
97 | return 0; | |
ed576acd | 98 | if ((bl = EVP_CIPHER_CTX_get_block_size(in->cctx)) < 0) |
d5f85429 | 99 | return 0; |
846ec07d | 100 | if (!EVP_CIPHER_CTX_copy(out->cctx, in->cctx)) |
0f113f3e | 101 | return 0; |
0f113f3e MC |
102 | memcpy(out->k1, in->k1, bl); |
103 | memcpy(out->k2, in->k2, bl); | |
104 | memcpy(out->tbl, in->tbl, bl); | |
105 | memcpy(out->last_block, in->last_block, bl); | |
106 | out->nlast_block = in->nlast_block; | |
107 | return 1; | |
108 | } | |
c8ef656d | 109 | |
0f113f3e MC |
110 | int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen, |
111 | const EVP_CIPHER *cipher, ENGINE *impl) | |
112 | { | |
113 | static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = { 0 }; | |
d5f85429 | 114 | |
0f113f3e MC |
115 | /* All zeros means restart */ |
116 | if (!key && !cipher && !impl && keylen == 0) { | |
117 | /* Not initialised */ | |
118 | if (ctx->nlast_block == -1) | |
119 | return 0; | |
846ec07d | 120 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e | 121 | return 0; |
ed576acd | 122 | memset(ctx->tbl, 0, EVP_CIPHER_CTX_get_block_size(ctx->cctx)); |
0f113f3e MC |
123 | ctx->nlast_block = 0; |
124 | return 1; | |
125 | } | |
0d4fb843 | 126 | /* Initialise context */ |
b896d943 MC |
127 | if (cipher != NULL) { |
128 | /* Ensure we can't use this ctx until we also have a key */ | |
129 | ctx->nlast_block = -1; | |
130 | if (!EVP_EncryptInit_ex(ctx->cctx, cipher, impl, NULL, NULL)) | |
131 | return 0; | |
132 | } | |
0f113f3e | 133 | /* Non-NULL key means initialisation complete */ |
b896d943 | 134 | if (key != NULL) { |
0f113f3e | 135 | int bl; |
d5f85429 | 136 | |
b896d943 MC |
137 | /* If anything fails then ensure we can't use this ctx */ |
138 | ctx->nlast_block = -1; | |
8d9fec17 | 139 | if (EVP_CIPHER_CTX_get0_cipher(ctx->cctx) == NULL) |
0f113f3e | 140 | return 0; |
8d9fec17 | 141 | if (EVP_CIPHER_CTX_set_key_length(ctx->cctx, keylen) <= 0) |
0f113f3e | 142 | return 0; |
846ec07d | 143 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, key, zero_iv)) |
0f113f3e | 144 | return 0; |
ed576acd | 145 | if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) < 0) |
d5f85429 | 146 | return 0; |
154ea425 | 147 | if (EVP_Cipher(ctx->cctx, ctx->tbl, zero_iv, bl) <= 0) |
0f113f3e MC |
148 | return 0; |
149 | make_kn(ctx->k1, ctx->tbl, bl); | |
150 | make_kn(ctx->k2, ctx->k1, bl); | |
151 | OPENSSL_cleanse(ctx->tbl, bl); | |
152 | /* Reset context again ready for first data block */ | |
846ec07d | 153 | if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv)) |
0f113f3e MC |
154 | return 0; |
155 | /* Zero tbl so resume works */ | |
156 | memset(ctx->tbl, 0, bl); | |
157 | ctx->nlast_block = 0; | |
158 | } | |
159 | return 1; | |
160 | } | |
8c968e03 DSH |
161 | |
162 | int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen) | |
0f113f3e MC |
163 | { |
164 | const unsigned char *data = in; | |
d5f85429 | 165 | int bl; |
dc19f2f6 | 166 | size_t max_burst_blocks, cipher_blocks; |
167 | unsigned char buf[LOCAL_BUF_SIZE]; | |
d5f85429 | 168 | |
0f113f3e MC |
169 | if (ctx->nlast_block == -1) |
170 | return 0; | |
171 | if (dlen == 0) | |
172 | return 1; | |
ed576acd | 173 | if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) < 0) |
d5f85429 | 174 | return 0; |
0f113f3e MC |
175 | /* Copy into partial block if we need to */ |
176 | if (ctx->nlast_block > 0) { | |
177 | size_t nleft; | |
d5f85429 | 178 | |
0f113f3e MC |
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 */ | |
154ea425 | 190 | if (EVP_Cipher(ctx->cctx, ctx->tbl, ctx->last_block, bl) <= 0) |
0f113f3e MC |
191 | return 0; |
192 | } | |
193 | /* Encrypt all but one of the complete blocks left */ | |
dc19f2f6 | 194 | |
195 | max_burst_blocks = LOCAL_BUF_SIZE / bl; | |
196 | cipher_blocks = (dlen - 1) / bl; | |
197 | if (max_burst_blocks == 0) { | |
198 | /* | |
e8dc77f8 | 199 | * When block length is greater than local buffer size, |
dc19f2f6 | 200 | * use ctx->tbl as cipher output. |
201 | */ | |
202 | while (dlen > (size_t)bl) { | |
203 | if (EVP_Cipher(ctx->cctx, ctx->tbl, data, bl) <= 0) | |
204 | return 0; | |
205 | dlen -= bl; | |
206 | data += bl; | |
207 | } | |
208 | } else { | |
209 | while (cipher_blocks > max_burst_blocks) { | |
210 | if (EVP_Cipher(ctx->cctx, buf, data, max_burst_blocks * bl) <= 0) | |
211 | return 0; | |
212 | dlen -= max_burst_blocks * bl; | |
213 | data += max_burst_blocks * bl; | |
214 | cipher_blocks -= max_burst_blocks; | |
215 | } | |
216 | if (cipher_blocks > 0) { | |
217 | if (EVP_Cipher(ctx->cctx, buf, data, cipher_blocks * bl) <= 0) | |
218 | return 0; | |
219 | dlen -= cipher_blocks * bl; | |
220 | data += cipher_blocks * bl; | |
221 | memcpy(ctx->tbl, &buf[(cipher_blocks - 1) * bl], bl); | |
222 | } | |
0f113f3e MC |
223 | } |
224 | /* Copy any data left to last block buffer */ | |
225 | memcpy(ctx->last_block, data, dlen); | |
226 | ctx->nlast_block = dlen; | |
227 | return 1; | |
8c968e03 | 228 | |
0f113f3e | 229 | } |
8c968e03 | 230 | |
c8ef656d | 231 | int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen) |
0f113f3e MC |
232 | { |
233 | int i, bl, lb; | |
d5f85429 | 234 | |
0f113f3e MC |
235 | if (ctx->nlast_block == -1) |
236 | return 0; | |
ed576acd | 237 | if ((bl = EVP_CIPHER_CTX_get_block_size(ctx->cctx)) < 0) |
d5f85429 | 238 | return 0; |
f6dead1b RH |
239 | if (poutlen != NULL) |
240 | *poutlen = (size_t)bl; | |
0f113f3e MC |
241 | if (!out) |
242 | return 1; | |
243 | lb = ctx->nlast_block; | |
244 | /* Is last block complete? */ | |
245 | if (lb == bl) { | |
246 | for (i = 0; i < bl; i++) | |
247 | out[i] = ctx->last_block[i] ^ ctx->k1[i]; | |
248 | } else { | |
249 | ctx->last_block[lb] = 0x80; | |
250 | if (bl - lb > 1) | |
251 | memset(ctx->last_block + lb + 1, 0, bl - lb - 1); | |
252 | for (i = 0; i < bl; i++) | |
253 | out[i] = ctx->last_block[i] ^ ctx->k2[i]; | |
254 | } | |
6d774732 | 255 | if (EVP_Cipher(ctx->cctx, out, out, bl) <= 0) { |
0f113f3e MC |
256 | OPENSSL_cleanse(out, bl); |
257 | return 0; | |
258 | } | |
259 | return 1; | |
260 | } | |
c8ef656d DSH |
261 | |
262 | int CMAC_resume(CMAC_CTX *ctx) | |
0f113f3e MC |
263 | { |
264 | if (ctx->nlast_block == -1) | |
265 | return 0; | |
266 | /* | |
0d4fb843 | 267 | * The buffer "tbl" contains the last fully encrypted block which is the |
0f113f3e | 268 | * last IV (or all zeroes if no last encrypted block). The last block has |
0d4fb843 | 269 | * not been modified since CMAC_final(). So reinitialising using the last |
0f113f3e MC |
270 | * decrypted block will allow CMAC to continue after calling |
271 | * CMAC_Final(). | |
272 | */ | |
512fdfdf | 273 | return EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, ctx->tbl); |
0f113f3e | 274 | } |