2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2011 The FreeBSD Project. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
29 * SHA256-based Unix crypt implementation. Released into the Public Domain by
30 * Ulrich Drepper <drepper@redhat.com>. */
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/endian.h>
36 #include <sys/param.h>
49 /* Define our magic string to mark salt for SHA256 "encryption" replacement. */
50 static const char sha256_salt_prefix[] = "$5$";
52 /* Prefix for optional rounds specification. */
53 static const char sha256_rounds_prefix[] = "rounds=";
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
65 crypt_sha256(const char *key, const char *salt, char *buffer)
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;
78 /* Default number of rounds. */
79 rounds = ROUNDS_DEFAULT;
80 rounds_custom = false;
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;
88 if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1)
90 num = salt + sizeof(sha256_rounds_prefix) - 1;
91 srounds = strtoul(num, &endp, 10);
95 rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
100 salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX);
101 key_len = strlen(key);
103 /* Prepare for the real work. */
106 /* Add the key string. */
107 SHA256_Update(&ctx, key, key_len);
109 /* The last part is the salt string. This must be at most 8
110 * characters and it ends at the first `$' character (for
111 * compatibility with existing implementations). */
112 SHA256_Update(&ctx, salt, salt_len);
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);
119 SHA256_Update(&alt_ctx, key, key_len);
122 SHA256_Update(&alt_ctx, salt, salt_len);
125 SHA256_Update(&alt_ctx, key, key_len);
127 /* Now get result of this (32 bytes) and add it to the other context. */
128 SHA256_Final(alt_result, &alt_ctx);
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);
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)
139 SHA256_Update(&ctx, alt_result, 32);
141 SHA256_Update(&ctx, key, key_len);
143 /* Create intermediate result. */
144 SHA256_Final(alt_result, &ctx);
146 /* Start computation of P byte sequence. */
147 SHA256_Init(&alt_ctx);
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);
153 /* Finish the digest. */
154 SHA256_Final(temp_result, &alt_ctx);
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);
162 memcpy(cp, temp_result, cnt);
164 /* Start computation of S byte sequence. */
165 SHA256_Init(&alt_ctx);
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);
171 /* Finish the digest. */
172 SHA256_Final(temp_result, &alt_ctx);
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);
180 memcpy(cp, temp_result, cnt);
182 /* Repeatedly run the collected hash value through SHA256 to burn CPU
184 for (cnt = 0; cnt < rounds; ++cnt) {
188 /* Add key or last result. */
190 SHA256_Update(&ctx, p_bytes, key_len);
192 SHA256_Update(&ctx, alt_result, 32);
194 /* Add salt for numbers not divisible by 3. */
196 SHA256_Update(&ctx, s_bytes, salt_len);
198 /* Add key for numbers not divisible by 7. */
200 SHA256_Update(&ctx, p_bytes, key_len);
202 /* Add key or last result. */
204 SHA256_Update(&ctx, alt_result, 32);
206 SHA256_Update(&ctx, p_bytes, key_len);
208 /* Create intermediate result. */
209 SHA256_Final(alt_result, &ctx);
212 /* Now we can construct the result string. It consists of three
214 cp = stpcpy(buffer, sha256_salt_prefix);
217 cp += sprintf(cp, "%s%zu$", sha256_rounds_prefix, rounds);
219 cp = stpncpy(cp, salt, salt_len);
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. */
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. */
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);
257 static const struct {
259 const char result[32];
262 /* Test vectors from FIPS 180-2: appendix B.1. */
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"
268 /* Test vectors from FIPS 180-2: appendix B.2. */
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"
274 /* Test vectors from the NESSIE project. */
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"
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"
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"
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"
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"
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"
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"
313 #define ntests (sizeof (tests) / sizeof (tests[0]))
315 static const struct {
318 const char *expected;
322 "$5$saltstring", "Hello world!",
323 "$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5"
326 "$5$rounds=10000$saltstringsaltstring", "Hello world!",
327 "$5$rounds=10000$saltstringsaltst$3xv.VbSHBb41AL9AvLeujZkZRBAwqFMz2."
331 "$5$rounds=5000$toolongsaltstring", "This is just a test",
332 "$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8"
336 "$5$rounds=1400$anotherlongsaltstring",
337 "a very much longer text to encrypt. This one even stretches over more"
339 "$5$rounds=1400$anotherlongsalts$Rx.j8H.h8HjEDGomFU8bDkXm3XIUnzyxf12"
343 "$5$rounds=77777$short",
344 "we have a short salt string but not a short password",
345 "$5$rounds=77777$short$JiO1O3ZpDAxGJeaDIuqCoEFysAe1mZNJRs3pw0KQRd/"
348 "$5$rounds=123456$asaltof16chars..", "a short string",
349 "$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/"
353 "$5$rounds=10$roundstoolow", "the minimum number is still observed",
354 "$5$rounds=1000$roundstoolow$yfvwcWrQ8l/K0DAWyuPMDNHpIVlTQebY9l/gL97"
359 #define ntests2 (sizeof (tests2) / sizeof (tests2[0]))
369 for (cnt = 0; cnt < (int)ntests; ++cnt) {
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]);
377 for (i = 0; i < 32; i++)
378 printf("%02X", sum[i]);
380 printf("test %d run %d failed\n", cnt, 1);
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]);
392 for (i = 0; i < 32; i++)
393 printf("%02X", sum[i]);
395 printf("test %d run %d failed\n", cnt, 2);
400 /* Test vector from FIPS 180-2: appendix B.3. */
403 memset(buf, 'a', sizeof(buf));
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";
412 if (memcmp(expected, sum, 32) != 0) {
413 printf("test %d failed\n", cnt);
417 for (cnt = 0; cnt < ntests2; ++cnt) {
418 char *cp = crypt_sha256(tests2[cnt].input, tests2[cnt].salt);
420 if (strcmp(cp, tests2[cnt].expected) != 0) {
421 printf("test %d: expected \"%s\", got \"%s\"\n",
422 cnt, tests2[cnt].expected, cp);
428 puts("all tests OK");