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