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