1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2011 The FreeBSD Project. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 /* Based on: 29 * SHA256-based Unix crypt implementation. Released into the Public Domain by 30 * Ulrich Drepper <drepper@redhat.com>. */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/endian.h> 36 #include <sys/param.h> 37 38 #include <errno.h> 39 #include <limits.h> 40 #include <sha256.h> 41 #include <stdbool.h> 42 #include <stdint.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 47 #include "crypt.h" 48 49 /* Define our magic string to mark salt for SHA256 "encryption" replacement. */ 50 static const char sha256_salt_prefix[] = "$5$"; 51 52 /* Prefix for optional rounds specification. */ 53 static const char sha256_rounds_prefix[] = "rounds="; 54 55 /* Maximum salt string length. */ 56 #define SALT_LEN_MAX 16 57 /* Default number of rounds if not explicitly specified. */ 58 #define ROUNDS_DEFAULT 5000 59 /* Minimum number of rounds. */ 60 #define ROUNDS_MIN 1000 61 /* Maximum number of rounds. */ 62 #define ROUNDS_MAX 999999999 63 64 int 65 crypt_sha256(const char *key, const char *salt, char *buffer) 66 { 67 u_long srounds; 68 uint8_t alt_result[32], temp_result[32]; 69 SHA256_CTX ctx, alt_ctx; 70 size_t salt_len, key_len, cnt, rounds; 71 char *cp, *copied_key, *copied_salt, *p_bytes, *s_bytes, *endp; 72 const char *num; 73 bool rounds_custom; 74 75 copied_key = NULL; 76 copied_salt = NULL; 77 78 /* Default number of rounds. */ 79 rounds = ROUNDS_DEFAULT; 80 rounds_custom = false; 81 82 /* Find beginning of salt string. The prefix should normally always 83 * be present. Just in case it is not. */ 84 if (strncmp(sha256_salt_prefix, salt, sizeof(sha256_salt_prefix) - 1) == 0) 85 /* Skip salt prefix. */ 86 salt += sizeof(sha256_salt_prefix) - 1; 87 88 if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1) 89 == 0) { 90 num = salt + sizeof(sha256_rounds_prefix) - 1; 91 srounds = strtoul(num, &endp, 10); 92 93 if (*endp == '$') { 94 salt = endp + 1; 95 rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX)); 96 rounds_custom = true; 97 } 98 } 99 100 salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX); 101 key_len = strlen(key); 102 103 /* Prepare for the real work. */ 104 SHA256_Init(&ctx); 105 106 /* Add the key string. */ 107 SHA256_Update(&ctx, key, key_len); 108 109 /* The last part is the salt string. This must be at most 8 110 * characters and it ends at the first `$' character (for 111 * compatibility with existing implementations). */ 112 SHA256_Update(&ctx, salt, salt_len); 113 114 /* Compute alternate SHA256 sum with input KEY, SALT, and KEY. The 115 * final result will be added to the first context. */ 116 SHA256_Init(&alt_ctx); 117 118 /* Add key. */ 119 SHA256_Update(&alt_ctx, key, key_len); 120 121 /* Add salt. */ 122 SHA256_Update(&alt_ctx, salt, salt_len); 123 124 /* Add key again. */ 125 SHA256_Update(&alt_ctx, key, key_len); 126 127 /* Now get result of this (32 bytes) and add it to the other context. */ 128 SHA256_Final(alt_result, &alt_ctx); 129 130 /* Add for any character in the key one byte of the alternate sum. */ 131 for (cnt = key_len; cnt > 32; cnt -= 32) 132 SHA256_Update(&ctx, alt_result, 32); 133 SHA256_Update(&ctx, alt_result, cnt); 134 135 /* Take the binary representation of the length of the key and for 136 * every 1 add the alternate sum, for every 0 the key. */ 137 for (cnt = key_len; cnt > 0; cnt >>= 1) 138 if ((cnt & 1) != 0) 139 SHA256_Update(&ctx, alt_result, 32); 140 else 141 SHA256_Update(&ctx, key, key_len); 142 143 /* Create intermediate result. */ 144 SHA256_Final(alt_result, &ctx); 145 146 /* Start computation of P byte sequence. */ 147 SHA256_Init(&alt_ctx); 148 149 /* For every character in the password add the entire password. */ 150 for (cnt = 0; cnt < key_len; ++cnt) 151 SHA256_Update(&alt_ctx, key, key_len); 152 153 /* Finish the digest. */ 154 SHA256_Final(temp_result, &alt_ctx); 155 156 /* Create byte sequence P. */ 157 cp = p_bytes = alloca(key_len); 158 for (cnt = key_len; cnt >= 32; cnt -= 32) { 159 memcpy(cp, temp_result, 32); 160 cp += 32; 161 } 162 memcpy(cp, temp_result, cnt); 163 164 /* Start computation of S byte sequence. */ 165 SHA256_Init(&alt_ctx); 166 167 /* For every character in the password add the entire password. */ 168 for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt) 169 SHA256_Update(&alt_ctx, salt, salt_len); 170 171 /* Finish the digest. */ 172 SHA256_Final(temp_result, &alt_ctx); 173 174 /* Create byte sequence S. */ 175 cp = s_bytes = alloca(salt_len); 176 for (cnt = salt_len; cnt >= 32; cnt -= 32) { 177 memcpy(cp, temp_result, 32); 178 cp += 32; 179 } 180 memcpy(cp, temp_result, cnt); 181 182 /* Repeatedly run the collected hash value through SHA256 to burn CPU 183 * cycles. */ 184 for (cnt = 0; cnt < rounds; ++cnt) { 185 /* New context. */ 186 SHA256_Init(&ctx); 187 188 /* Add key or last result. */ 189 if ((cnt & 1) != 0) 190 SHA256_Update(&ctx, p_bytes, key_len); 191 else 192 SHA256_Update(&ctx, alt_result, 32); 193 194 /* Add salt for numbers not divisible by 3. */ 195 if (cnt % 3 != 0) 196 SHA256_Update(&ctx, s_bytes, salt_len); 197 198 /* Add key for numbers not divisible by 7. */ 199 if (cnt % 7 != 0) 200 SHA256_Update(&ctx, p_bytes, key_len); 201 202 /* Add key or last result. */ 203 if ((cnt & 1) != 0) 204 SHA256_Update(&ctx, alt_result, 32); 205 else 206 SHA256_Update(&ctx, p_bytes, key_len); 207 208 /* Create intermediate result. */ 209 SHA256_Final(alt_result, &ctx); 210 } 211 212 /* Now we can construct the result string. It consists of three 213 * parts. */ 214 cp = stpcpy(buffer, sha256_salt_prefix); 215 216 if (rounds_custom) 217 cp += sprintf(cp, "%s%zu$", sha256_rounds_prefix, rounds); 218 219 cp = stpncpy(cp, salt, salt_len); 220 221 *cp++ = '$'; 222 223 b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4, &cp); 224 b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4, &cp); 225 b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4, &cp); 226 b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4, &cp); 227 b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4, &cp); 228 b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4, &cp); 229 b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4, &cp); 230 b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4, &cp); 231 b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4, &cp); 232 b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4, &cp); 233 b64_from_24bit(0, alt_result[31], alt_result[30], 3, &cp); 234 *cp = '\0'; /* Terminate the string. */ 235 236 /* Clear the buffer for the intermediate result so that people 237 * attaching to processes or reading core dumps cannot get any 238 * information. We do it in this way to clear correct_words[] inside 239 * the SHA256 implementation as well. */ 240 SHA256_Init(&ctx); 241 SHA256_Final(alt_result, &ctx); 242 memset(temp_result, '\0', sizeof(temp_result)); 243 memset(p_bytes, '\0', key_len); 244 memset(s_bytes, '\0', salt_len); 245 memset(&ctx, '\0', sizeof(ctx)); 246 memset(&alt_ctx, '\0', sizeof(alt_ctx)); 247 if (copied_key != NULL) 248 memset(copied_key, '\0', key_len); 249 if (copied_salt != NULL) 250 memset(copied_salt, '\0', salt_len); 251 252 return (0); 253 } 254 255 #ifdef TEST 256 257 static const struct { 258 const char *input; 259 const char result[32]; 260 } tests[] = 261 { 262 /* Test vectors from FIPS 180-2: appendix B.1. */ 263 { 264 "abc", 265 "\xba\x78\x16\xbf\x8f\x01\xcf\xea\x41\x41\x40\xde\x5d\xae\x22\x23" 266 "\xb0\x03\x61\xa3\x96\x17\x7a\x9c\xb4\x10\xff\x61\xf2\x00\x15\xad" 267 }, 268 /* Test vectors from FIPS 180-2: appendix B.2. */ 269 { 270 "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 271 "\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39" 272 "\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1" 273 }, 274 /* Test vectors from the NESSIE project. */ 275 { 276 "", 277 "\xe3\xb0\xc4\x42\x98\xfc\x1c\x14\x9a\xfb\xf4\xc8\x99\x6f\xb9\x24" 278 "\x27\xae\x41\xe4\x64\x9b\x93\x4c\xa4\x95\x99\x1b\x78\x52\xb8\x55" 279 }, 280 { 281 "a", 282 "\xca\x97\x81\x12\xca\x1b\xbd\xca\xfa\xc2\x31\xb3\x9a\x23\xdc\x4d" 283 "\xa7\x86\xef\xf8\x14\x7c\x4e\x72\xb9\x80\x77\x85\xaf\xee\x48\xbb" 284 }, 285 { 286 "message digest", 287 "\xf7\x84\x6f\x55\xcf\x23\xe1\x4e\xeb\xea\xb5\xb4\xe1\x55\x0c\xad" 288 "\x5b\x50\x9e\x33\x48\xfb\xc4\xef\xa3\xa1\x41\x3d\x39\x3c\xb6\x50" 289 }, 290 { 291 "abcdefghijklmnopqrstuvwxyz", 292 "\x71\xc4\x80\xdf\x93\xd6\xae\x2f\x1e\xfa\xd1\x44\x7c\x66\xc9\x52" 293 "\x5e\x31\x62\x18\xcf\x51\xfc\x8d\x9e\xd8\x32\xf2\xda\xf1\x8b\x73" 294 }, 295 { 296 "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 297 "\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39" 298 "\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1" 299 }, 300 { 301 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", 302 "\xdb\x4b\xfc\xbd\x4d\xa0\xcd\x85\xa6\x0c\x3c\x37\xd3\xfb\xd8\x80" 303 "\x5c\x77\xf1\x5f\xc6\xb1\xfd\xfe\x61\x4e\xe0\xa7\xc8\xfd\xb4\xc0" 304 }, 305 { 306 "123456789012345678901234567890123456789012345678901234567890" 307 "12345678901234567890", 308 "\xf3\x71\xbc\x4a\x31\x1f\x2b\x00\x9e\xef\x95\x2d\xd8\x3c\xa8\x0e" 309 "\x2b\x60\x02\x6c\x8e\x93\x55\x92\xd0\xf9\xc3\x08\x45\x3c\x81\x3e" 310 } 311 }; 312 313 #define ntests (sizeof (tests) / sizeof (tests[0])) 314 315 static const struct { 316 const char *salt; 317 const char *input; 318 const char *expected; 319 } tests2[] = 320 { 321 { 322 "$5$saltstring", "Hello world!", 323 "$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5" 324 }, 325 { 326 "$5$rounds=10000$saltstringsaltstring", "Hello world!", 327 "$5$rounds=10000$saltstringsaltst$3xv.VbSHBb41AL9AvLeujZkZRBAwqFMz2." 328 "opqey6IcA" 329 }, 330 { 331 "$5$rounds=5000$toolongsaltstring", "This is just a test", 332 "$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8" 333 "mGRcvxa5" 334 }, 335 { 336 "$5$rounds=1400$anotherlongsaltstring", 337 "a very much longer text to encrypt. This one even stretches over more" 338 "than one line.", 339 "$5$rounds=1400$anotherlongsalts$Rx.j8H.h8HjEDGomFU8bDkXm3XIUnzyxf12" 340 "oP84Bnq1" 341 }, 342 { 343 "$5$rounds=77777$short", 344 "we have a short salt string but not a short password", 345 "$5$rounds=77777$short$JiO1O3ZpDAxGJeaDIuqCoEFysAe1mZNJRs3pw0KQRd/" 346 }, 347 { 348 "$5$rounds=123456$asaltof16chars..", "a short string", 349 "$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/" 350 "cZKmF/wJvD" 351 }, 352 { 353 "$5$rounds=10$roundstoolow", "the minimum number is still observed", 354 "$5$rounds=1000$roundstoolow$yfvwcWrQ8l/K0DAWyuPMDNHpIVlTQebY9l/gL97" 355 "2bIC" 356 }, 357 }; 358 359 #define ntests2 (sizeof (tests2) / sizeof (tests2[0])) 360 361 int 362 main(void) 363 { 364 SHA256_CTX ctx; 365 uint8_t sum[32]; 366 int result = 0; 367 int i, cnt; 368 369 for (cnt = 0; cnt < (int)ntests; ++cnt) { 370 SHA256_Init(&ctx); 371 SHA256_Update(&ctx, tests[cnt].input, strlen(tests[cnt].input)); 372 SHA256_Final(sum, &ctx); 373 if (memcmp(tests[cnt].result, sum, 32) != 0) { 374 for (i = 0; i < 32; i++) 375 printf("%02X", tests[cnt].result[i]); 376 printf("\n"); 377 for (i = 0; i < 32; i++) 378 printf("%02X", sum[i]); 379 printf("\n"); 380 printf("test %d run %d failed\n", cnt, 1); 381 result = 1; 382 } 383 384 SHA256_Init(&ctx); 385 for (i = 0; tests[cnt].input[i] != '\0'; ++i) 386 SHA256_Update(&ctx, &tests[cnt].input[i], 1); 387 SHA256_Final(sum, &ctx); 388 if (memcmp(tests[cnt].result, sum, 32) != 0) { 389 for (i = 0; i < 32; i++) 390 printf("%02X", tests[cnt].result[i]); 391 printf("\n"); 392 for (i = 0; i < 32; i++) 393 printf("%02X", sum[i]); 394 printf("\n"); 395 printf("test %d run %d failed\n", cnt, 2); 396 result = 1; 397 } 398 } 399 400 /* Test vector from FIPS 180-2: appendix B.3. */ 401 char buf[1000]; 402 403 memset(buf, 'a', sizeof(buf)); 404 SHA256_Init(&ctx); 405 for (i = 0; i < 1000; ++i) 406 SHA256_Update(&ctx, buf, sizeof(buf)); 407 SHA256_Final(sum, &ctx); 408 static const char expected[32] = 409 "\xcd\xc7\x6e\x5c\x99\x14\xfb\x92\x81\xa1\xc7\xe2\x84\xd7\x3e\x67" 410 "\xf1\x80\x9a\x48\xa4\x97\x20\x0e\x04\x6d\x39\xcc\xc7\x11\x2c\xd0"; 411 412 if (memcmp(expected, sum, 32) != 0) { 413 printf("test %d failed\n", cnt); 414 result = 1; 415 } 416 417 for (cnt = 0; cnt < ntests2; ++cnt) { 418 char *cp = crypt_sha256(tests2[cnt].input, tests2[cnt].salt); 419 420 if (strcmp(cp, tests2[cnt].expected) != 0) { 421 printf("test %d: expected \"%s\", got \"%s\"\n", 422 cnt, tests2[cnt].expected, cp); 423 result = 1; 424 } 425 } 426 427 if (result == 0) 428 puts("all tests OK"); 429 430 return result; 431 } 432 433 #endif /* TEST */ 434