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