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12fb8c3d | 1 | /* |
3c7d0945 | 2 | * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved. |
12fb8c3d | 3 | * |
0db63de9 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
12fb8c3d 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 | |
8 | */ | |
9 | ||
10 | #include <stdlib.h> | |
11 | #include <string.h> | |
12 | #include <openssl/crypto.h> | |
13 | #include <openssl/err.h> | |
14 | #include <openssl/rand.h> | |
12fb8c3d | 15 | #include "internal/thread_once.h" |
6decf943 | 16 | #include "rand_lcl.h" |
8bf36651 | 17 | |
12fb8c3d | 18 | /* |
75e2c877 | 19 | * Implementation of NIST SP 800-90A CTR DRBG. |
12fb8c3d | 20 | */ |
75e2c877 | 21 | static void inc_128(RAND_DRBG_CTR *ctr) |
12fb8c3d RS |
22 | { |
23 | int i; | |
24 | unsigned char c; | |
75e2c877 | 25 | unsigned char *p = &ctr->V[15]; |
12fb8c3d RS |
26 | |
27 | for (i = 0; i < 16; i++, p--) { | |
28 | c = *p; | |
29 | c++; | |
30 | *p = c; | |
31 | if (c != 0) { | |
32 | /* If we didn't wrap around, we're done. */ | |
33 | break; | |
34 | } | |
35 | } | |
36 | } | |
37 | ||
75e2c877 | 38 | static void ctr_XOR(RAND_DRBG_CTR *ctr, const unsigned char *in, size_t inlen) |
12fb8c3d RS |
39 | { |
40 | size_t i, n; | |
41 | ||
42 | if (in == NULL || inlen == 0) | |
43 | return; | |
44 | ||
45 | /* | |
46 | * Any zero padding will have no effect on the result as we | |
47 | * are XORing. So just process however much input we have. | |
48 | */ | |
75e2c877 | 49 | n = inlen < ctr->keylen ? inlen : ctr->keylen; |
12fb8c3d | 50 | for (i = 0; i < n; i++) |
75e2c877 RS |
51 | ctr->K[i] ^= in[i]; |
52 | if (inlen <= ctr->keylen) | |
12fb8c3d RS |
53 | return; |
54 | ||
75e2c877 | 55 | n = inlen - ctr->keylen; |
12fb8c3d RS |
56 | if (n > 16) { |
57 | /* Should never happen */ | |
58 | n = 16; | |
59 | } | |
b8a437ff | 60 | for (i = 0; i < n; i++) |
75e2c877 | 61 | ctr->V[i] ^= in[i + ctr->keylen]; |
12fb8c3d RS |
62 | } |
63 | ||
64 | /* | |
65 | * Process a complete block using BCC algorithm of SP 800-90A 10.3.3 | |
66 | */ | |
dbdcc04f KR |
67 | __owur static int ctr_BCC_block(RAND_DRBG_CTR *ctr, unsigned char *out, |
68 | const unsigned char *in) | |
12fb8c3d | 69 | { |
dbdcc04f | 70 | int i, outlen = AES_BLOCK_SIZE; |
12fb8c3d RS |
71 | |
72 | for (i = 0; i < 16; i++) | |
73 | out[i] ^= in[i]; | |
dbdcc04f KR |
74 | |
75 | if (!EVP_CipherUpdate(ctr->ctx_df, out, &outlen, out, AES_BLOCK_SIZE) | |
76 | || outlen != AES_BLOCK_SIZE) | |
77 | return 0; | |
78 | return 1; | |
12fb8c3d RS |
79 | } |
80 | ||
81 | ||
82 | /* | |
83 | * Handle several BCC operations for as much data as we need for K and X | |
84 | */ | |
dbdcc04f | 85 | __owur static int ctr_BCC_blocks(RAND_DRBG_CTR *ctr, const unsigned char *in) |
12fb8c3d | 86 | { |
dbdcc04f KR |
87 | if (!ctr_BCC_block(ctr, ctr->KX, in) |
88 | || !ctr_BCC_block(ctr, ctr->KX + 16, in)) | |
89 | return 0; | |
90 | if (ctr->keylen != 16 && !ctr_BCC_block(ctr, ctr->KX + 32, in)) | |
91 | return 0; | |
92 | return 1; | |
12fb8c3d RS |
93 | } |
94 | ||
95 | /* | |
96 | * Initialise BCC blocks: these have the value 0,1,2 in leftmost positions: | |
97 | * see 10.3.1 stage 7. | |
98 | */ | |
dbdcc04f | 99 | __owur static int ctr_BCC_init(RAND_DRBG_CTR *ctr) |
12fb8c3d | 100 | { |
75e2c877 RS |
101 | memset(ctr->KX, 0, 48); |
102 | memset(ctr->bltmp, 0, 16); | |
dbdcc04f KR |
103 | if (!ctr_BCC_block(ctr, ctr->KX, ctr->bltmp)) |
104 | return 0; | |
75e2c877 | 105 | ctr->bltmp[3] = 1; |
dbdcc04f KR |
106 | if (!ctr_BCC_block(ctr, ctr->KX + 16, ctr->bltmp)) |
107 | return 0; | |
75e2c877 RS |
108 | if (ctr->keylen != 16) { |
109 | ctr->bltmp[3] = 2; | |
dbdcc04f KR |
110 | if (!ctr_BCC_block(ctr, ctr->KX + 32, ctr->bltmp)) |
111 | return 0; | |
12fb8c3d | 112 | } |
dbdcc04f | 113 | return 1; |
12fb8c3d RS |
114 | } |
115 | ||
116 | /* | |
117 | * Process several blocks into BCC algorithm, some possibly partial | |
118 | */ | |
dbdcc04f KR |
119 | __owur static int ctr_BCC_update(RAND_DRBG_CTR *ctr, |
120 | const unsigned char *in, size_t inlen) | |
12fb8c3d RS |
121 | { |
122 | if (in == NULL || inlen == 0) | |
dbdcc04f | 123 | return 1; |
12fb8c3d RS |
124 | |
125 | /* If we have partial block handle it first */ | |
75e2c877 RS |
126 | if (ctr->bltmp_pos) { |
127 | size_t left = 16 - ctr->bltmp_pos; | |
12fb8c3d RS |
128 | |
129 | /* If we now have a complete block process it */ | |
130 | if (inlen >= left) { | |
75e2c877 | 131 | memcpy(ctr->bltmp + ctr->bltmp_pos, in, left); |
dbdcc04f KR |
132 | if (!ctr_BCC_blocks(ctr, ctr->bltmp)) |
133 | return 0; | |
75e2c877 | 134 | ctr->bltmp_pos = 0; |
12fb8c3d RS |
135 | inlen -= left; |
136 | in += left; | |
137 | } | |
138 | } | |
139 | ||
140 | /* Process zero or more complete blocks */ | |
141 | for (; inlen >= 16; in += 16, inlen -= 16) { | |
dbdcc04f KR |
142 | if (!ctr_BCC_blocks(ctr, in)) |
143 | return 0; | |
12fb8c3d RS |
144 | } |
145 | ||
146 | /* Copy any remaining partial block to the temporary buffer */ | |
147 | if (inlen > 0) { | |
75e2c877 RS |
148 | memcpy(ctr->bltmp + ctr->bltmp_pos, in, inlen); |
149 | ctr->bltmp_pos += inlen; | |
12fb8c3d | 150 | } |
dbdcc04f | 151 | return 1; |
12fb8c3d RS |
152 | } |
153 | ||
dbdcc04f | 154 | __owur static int ctr_BCC_final(RAND_DRBG_CTR *ctr) |
12fb8c3d | 155 | { |
75e2c877 RS |
156 | if (ctr->bltmp_pos) { |
157 | memset(ctr->bltmp + ctr->bltmp_pos, 0, 16 - ctr->bltmp_pos); | |
dbdcc04f KR |
158 | if (!ctr_BCC_blocks(ctr, ctr->bltmp)) |
159 | return 0; | |
12fb8c3d | 160 | } |
dbdcc04f | 161 | return 1; |
12fb8c3d RS |
162 | } |
163 | ||
dbdcc04f KR |
164 | __owur static int ctr_df(RAND_DRBG_CTR *ctr, |
165 | const unsigned char *in1, size_t in1len, | |
166 | const unsigned char *in2, size_t in2len, | |
167 | const unsigned char *in3, size_t in3len) | |
12fb8c3d RS |
168 | { |
169 | static unsigned char c80 = 0x80; | |
170 | size_t inlen; | |
75e2c877 | 171 | unsigned char *p = ctr->bltmp; |
dbdcc04f | 172 | int outlen = AES_BLOCK_SIZE; |
12fb8c3d | 173 | |
dbdcc04f KR |
174 | if (!ctr_BCC_init(ctr)) |
175 | return 0; | |
12fb8c3d RS |
176 | if (in1 == NULL) |
177 | in1len = 0; | |
178 | if (in2 == NULL) | |
179 | in2len = 0; | |
180 | if (in3 == NULL) | |
181 | in3len = 0; | |
182 | inlen = in1len + in2len + in3len; | |
183 | /* Initialise L||N in temporary block */ | |
184 | *p++ = (inlen >> 24) & 0xff; | |
185 | *p++ = (inlen >> 16) & 0xff; | |
186 | *p++ = (inlen >> 8) & 0xff; | |
187 | *p++ = inlen & 0xff; | |
188 | ||
189 | /* NB keylen is at most 32 bytes */ | |
190 | *p++ = 0; | |
191 | *p++ = 0; | |
192 | *p++ = 0; | |
75e2c877 RS |
193 | *p = (unsigned char)((ctr->keylen + 16) & 0xff); |
194 | ctr->bltmp_pos = 8; | |
dbdcc04f KR |
195 | if (!ctr_BCC_update(ctr, in1, in1len) |
196 | || !ctr_BCC_update(ctr, in2, in2len) | |
197 | || !ctr_BCC_update(ctr, in3, in3len) | |
198 | || !ctr_BCC_update(ctr, &c80, 1) | |
199 | || !ctr_BCC_final(ctr)) | |
200 | return 0; | |
12fb8c3d | 201 | /* Set up key K */ |
dbdcc04f KR |
202 | if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->KX, NULL, 1)) |
203 | return 0; | |
12fb8c3d | 204 | /* X follows key K */ |
dbdcc04f KR |
205 | if (!EVP_CipherUpdate(ctr->ctx, ctr->KX, &outlen, ctr->KX + ctr->keylen, |
206 | AES_BLOCK_SIZE) | |
207 | || outlen != AES_BLOCK_SIZE) | |
208 | return 0; | |
209 | if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 16, &outlen, ctr->KX, | |
210 | AES_BLOCK_SIZE) | |
211 | || outlen != AES_BLOCK_SIZE) | |
212 | return 0; | |
75e2c877 | 213 | if (ctr->keylen != 16) |
dbdcc04f KR |
214 | if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 32, &outlen, ctr->KX + 16, |
215 | AES_BLOCK_SIZE) | |
216 | || outlen != AES_BLOCK_SIZE) | |
217 | return 0; | |
218 | return 1; | |
12fb8c3d RS |
219 | } |
220 | ||
221 | /* | |
222 | * NB the no-df Update in SP800-90A specifies a constant input length | |
223 | * of seedlen, however other uses of this algorithm pad the input with | |
224 | * zeroes if necessary and have up to two parameters XORed together, | |
75e2c877 | 225 | * so we handle both cases in this function instead. |
12fb8c3d | 226 | */ |
dbdcc04f KR |
227 | __owur static int ctr_update(RAND_DRBG *drbg, |
228 | const unsigned char *in1, size_t in1len, | |
229 | const unsigned char *in2, size_t in2len, | |
230 | const unsigned char *nonce, size_t noncelen) | |
12fb8c3d | 231 | { |
8212d505 | 232 | RAND_DRBG_CTR *ctr = &drbg->data.ctr; |
dbdcc04f | 233 | int outlen = AES_BLOCK_SIZE; |
12fb8c3d | 234 | |
dbdcc04f | 235 | /* correct key is already set up. */ |
75e2c877 | 236 | inc_128(ctr); |
dbdcc04f KR |
237 | if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outlen, ctr->V, AES_BLOCK_SIZE) |
238 | || outlen != AES_BLOCK_SIZE) | |
239 | return 0; | |
12fb8c3d RS |
240 | |
241 | /* If keylen longer than 128 bits need extra encrypt */ | |
75e2c877 RS |
242 | if (ctr->keylen != 16) { |
243 | inc_128(ctr); | |
dbdcc04f KR |
244 | if (!EVP_CipherUpdate(ctr->ctx, ctr->K+16, &outlen, ctr->V, |
245 | AES_BLOCK_SIZE) | |
246 | || outlen != AES_BLOCK_SIZE) | |
247 | return 0; | |
12fb8c3d | 248 | } |
75e2c877 | 249 | inc_128(ctr); |
dbdcc04f KR |
250 | if (!EVP_CipherUpdate(ctr->ctx, ctr->V, &outlen, ctr->V, AES_BLOCK_SIZE) |
251 | || outlen != AES_BLOCK_SIZE) | |
252 | return 0; | |
12fb8c3d RS |
253 | |
254 | /* If 192 bit key part of V is on end of K */ | |
75e2c877 RS |
255 | if (ctr->keylen == 24) { |
256 | memcpy(ctr->V + 8, ctr->V, 8); | |
257 | memcpy(ctr->V, ctr->K + 24, 8); | |
12fb8c3d RS |
258 | } |
259 | ||
8164d91d | 260 | if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { |
12fb8c3d RS |
261 | /* If no input reuse existing derived value */ |
262 | if (in1 != NULL || nonce != NULL || in2 != NULL) | |
dbdcc04f KR |
263 | if (!ctr_df(ctr, in1, in1len, nonce, noncelen, in2, in2len)) |
264 | return 0; | |
12fb8c3d RS |
265 | /* If this a reuse input in1len != 0 */ |
266 | if (in1len) | |
75e2c877 | 267 | ctr_XOR(ctr, ctr->KX, drbg->seedlen); |
12fb8c3d | 268 | } else { |
75e2c877 RS |
269 | ctr_XOR(ctr, in1, in1len); |
270 | ctr_XOR(ctr, in2, in2len); | |
12fb8c3d RS |
271 | } |
272 | ||
dbdcc04f KR |
273 | if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1)) |
274 | return 0; | |
275 | return 1; | |
12fb8c3d RS |
276 | } |
277 | ||
dbdcc04f KR |
278 | __owur static int drbg_ctr_instantiate(RAND_DRBG *drbg, |
279 | const unsigned char *entropy, size_t entropylen, | |
280 | const unsigned char *nonce, size_t noncelen, | |
281 | const unsigned char *pers, size_t perslen) | |
12fb8c3d | 282 | { |
8212d505 | 283 | RAND_DRBG_CTR *ctr = &drbg->data.ctr; |
12fb8c3d | 284 | |
aa048aef | 285 | if (entropy == NULL) |
4c78ba59 DSH |
286 | return 0; |
287 | ||
75e2c877 RS |
288 | memset(ctr->K, 0, sizeof(ctr->K)); |
289 | memset(ctr->V, 0, sizeof(ctr->V)); | |
dbdcc04f KR |
290 | if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1)) |
291 | return 0; | |
292 | if (!ctr_update(drbg, entropy, entropylen, pers, perslen, nonce, noncelen)) | |
293 | return 0; | |
12fb8c3d RS |
294 | return 1; |
295 | } | |
296 | ||
dbdcc04f KR |
297 | __owur static int drbg_ctr_reseed(RAND_DRBG *drbg, |
298 | const unsigned char *entropy, size_t entropylen, | |
299 | const unsigned char *adin, size_t adinlen) | |
12fb8c3d | 300 | { |
aa048aef | 301 | if (entropy == NULL) |
4c78ba59 | 302 | return 0; |
dbdcc04f KR |
303 | if (!ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0)) |
304 | return 0; | |
12fb8c3d RS |
305 | return 1; |
306 | } | |
307 | ||
dbdcc04f KR |
308 | __owur static int drbg_ctr_generate(RAND_DRBG *drbg, |
309 | unsigned char *out, size_t outlen, | |
310 | const unsigned char *adin, size_t adinlen) | |
12fb8c3d | 311 | { |
8212d505 | 312 | RAND_DRBG_CTR *ctr = &drbg->data.ctr; |
12fb8c3d RS |
313 | |
314 | if (adin != NULL && adinlen != 0) { | |
dbdcc04f KR |
315 | if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0)) |
316 | return 0; | |
12fb8c3d | 317 | /* This means we reuse derived value */ |
8164d91d | 318 | if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { |
12fb8c3d RS |
319 | adin = NULL; |
320 | adinlen = 1; | |
321 | } | |
322 | } else { | |
323 | adinlen = 0; | |
324 | } | |
325 | ||
326 | for ( ; ; ) { | |
dbdcc04f KR |
327 | int outl = AES_BLOCK_SIZE; |
328 | ||
75e2c877 | 329 | inc_128(ctr); |
12fb8c3d RS |
330 | if (outlen < 16) { |
331 | /* Use K as temp space as it will be updated */ | |
dbdcc04f KR |
332 | if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outl, ctr->V, |
333 | AES_BLOCK_SIZE) | |
334 | || outl != AES_BLOCK_SIZE) | |
335 | return 0; | |
75e2c877 | 336 | memcpy(out, ctr->K, outlen); |
12fb8c3d RS |
337 | break; |
338 | } | |
dbdcc04f KR |
339 | if (!EVP_CipherUpdate(ctr->ctx, out, &outl, ctr->V, AES_BLOCK_SIZE) |
340 | || outl != AES_BLOCK_SIZE) | |
341 | return 0; | |
12fb8c3d RS |
342 | out += 16; |
343 | outlen -= 16; | |
344 | if (outlen == 0) | |
345 | break; | |
346 | } | |
347 | ||
dbdcc04f KR |
348 | if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0)) |
349 | return 0; | |
12fb8c3d RS |
350 | return 1; |
351 | } | |
352 | ||
8212d505 | 353 | static int drbg_ctr_uninstantiate(RAND_DRBG *drbg) |
12fb8c3d | 354 | { |
dbdcc04f KR |
355 | EVP_CIPHER_CTX_free(drbg->data.ctr.ctx); |
356 | EVP_CIPHER_CTX_free(drbg->data.ctr.ctx_df); | |
8212d505 | 357 | OPENSSL_cleanse(&drbg->data.ctr, sizeof(drbg->data.ctr)); |
12fb8c3d RS |
358 | return 1; |
359 | } | |
360 | ||
8212d505 DMSP |
361 | static RAND_DRBG_METHOD drbg_ctr_meth = { |
362 | drbg_ctr_instantiate, | |
363 | drbg_ctr_reseed, | |
364 | drbg_ctr_generate, | |
365 | drbg_ctr_uninstantiate | |
366 | }; | |
367 | ||
368 | int drbg_ctr_init(RAND_DRBG *drbg) | |
12fb8c3d | 369 | { |
8212d505 | 370 | RAND_DRBG_CTR *ctr = &drbg->data.ctr; |
12fb8c3d RS |
371 | size_t keylen; |
372 | ||
31393fd9 | 373 | switch (drbg->type) { |
12fb8c3d RS |
374 | default: |
375 | /* This can't happen, but silence the compiler warning. */ | |
efb8128a | 376 | return 0; |
12fb8c3d RS |
377 | case NID_aes_128_ctr: |
378 | keylen = 16; | |
dbdcc04f | 379 | ctr->cipher = EVP_aes_128_ecb(); |
12fb8c3d RS |
380 | break; |
381 | case NID_aes_192_ctr: | |
382 | keylen = 24; | |
dbdcc04f | 383 | ctr->cipher = EVP_aes_192_ecb(); |
12fb8c3d RS |
384 | break; |
385 | case NID_aes_256_ctr: | |
386 | keylen = 32; | |
dbdcc04f | 387 | ctr->cipher = EVP_aes_256_ecb(); |
12fb8c3d RS |
388 | break; |
389 | } | |
390 | ||
8212d505 DMSP |
391 | drbg->meth = &drbg_ctr_meth; |
392 | ||
75e2c877 | 393 | ctr->keylen = keylen; |
dbdcc04f KR |
394 | if (ctr->ctx == NULL) |
395 | ctr->ctx = EVP_CIPHER_CTX_new(); | |
396 | if (ctr->ctx == NULL) | |
397 | return 0; | |
75e2c877 RS |
398 | drbg->strength = keylen * 8; |
399 | drbg->seedlen = keylen + 16; | |
12fb8c3d | 400 | |
8164d91d | 401 | if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) { |
12fb8c3d | 402 | /* df initialisation */ |
dbdcc04f | 403 | static const unsigned char df_key[32] = { |
c2e33a05 F |
404 | 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, |
405 | 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, | |
406 | 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, | |
407 | 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f | |
12fb8c3d | 408 | }; |
dbdcc04f KR |
409 | |
410 | if (ctr->ctx_df == NULL) | |
411 | ctr->ctx_df = EVP_CIPHER_CTX_new(); | |
412 | if (ctr->ctx_df == NULL) | |
413 | return 0; | |
12fb8c3d | 414 | /* Set key schedule for df_key */ |
dbdcc04f KR |
415 | if (!EVP_CipherInit_ex(ctr->ctx_df, ctr->cipher, NULL, df_key, NULL, 1)) |
416 | return 0; | |
75e2c877 | 417 | |
aa048aef | 418 | drbg->min_entropylen = ctr->keylen; |
3064b551 | 419 | drbg->max_entropylen = DRBG_MAX_LENGTH; |
aa048aef | 420 | drbg->min_noncelen = drbg->min_entropylen / 2; |
3064b551 | 421 | drbg->max_noncelen = DRBG_MAX_LENGTH; |
aa048aef DMSP |
422 | drbg->max_perslen = DRBG_MAX_LENGTH; |
423 | drbg->max_adinlen = DRBG_MAX_LENGTH; | |
12fb8c3d | 424 | } else { |
6c7d80ab P |
425 | #ifdef FIPS_MODE |
426 | RANDerr(RAND_F_DRBG_CTR_INIT, | |
427 | RAND_R_DERIVATION_FUNCTION_MANDATORY_FOR_FIPS); | |
428 | return 0; | |
429 | #else | |
aa048aef DMSP |
430 | drbg->min_entropylen = drbg->seedlen; |
431 | drbg->max_entropylen = drbg->seedlen; | |
12fb8c3d | 432 | /* Nonce not used */ |
aa048aef DMSP |
433 | drbg->min_noncelen = 0; |
434 | drbg->max_noncelen = 0; | |
435 | drbg->max_perslen = drbg->seedlen; | |
436 | drbg->max_adinlen = drbg->seedlen; | |
6c7d80ab | 437 | #endif |
12fb8c3d RS |
438 | } |
439 | ||
75e2c877 | 440 | drbg->max_request = 1 << 16; |
4917e911 | 441 | |
12fb8c3d RS |
442 | return 1; |
443 | } |