2 * Copyright (c) 2011 The FreeBSD Project. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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
27 * SHA256-based Unix crypt implementation. Released into the Public Domain by
28 * Ulrich Drepper <drepper@redhat.com>. */
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/endian.h>
34 #include <sys/param.h>
47 /* Define our magic string to mark salt for SHA256 "encryption" replacement. */
48 static const char sha256_salt_prefix[] = "$5$";
50 /* Prefix for optional rounds specification. */
51 static const char sha256_rounds_prefix[] = "rounds=";
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
63 crypt_sha256_r(const char *key, const char *salt, char *buffer, int buflen)
67 uint8_t alt_result[32], temp_result[32];
68 SHA256_CTX ctx, alt_ctx;
69 size_t salt_len, key_len, cnt, rounds;
70 char *cp, *copied_key, *copied_salt, *p_bytes, *s_bytes, *endp;
77 /* Default number of rounds. */
78 rounds = ROUNDS_DEFAULT;
79 rounds_custom = false;
81 /* Find beginning of salt string. The prefix should normally always
82 * be present. Just in case it is not. */
83 if (strncmp(sha256_salt_prefix, salt, sizeof(sha256_salt_prefix) - 1) == 0)
84 /* Skip salt prefix. */
85 salt += sizeof(sha256_salt_prefix) - 1;
87 if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1)
89 num = salt + sizeof(sha256_rounds_prefix) - 1;
90 srounds = strtoul(num, &endp, 10);
94 rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
99 salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX);
100 key_len = strlen(key);
102 /* Prepare for the real work. */
105 /* Add the key string. */
106 SHA256_Update(&ctx, key, key_len);
108 /* The last part is the salt string. This must be at most 8
109 * characters and it ends at the first `$' character (for
110 * compatibility with existing implementations). */
111 SHA256_Update(&ctx, salt, salt_len);
113 /* Compute alternate SHA256 sum with input KEY, SALT, and KEY. The
114 * final result will be added to the first context. */
115 SHA256_Init(&alt_ctx);
118 SHA256_Update(&alt_ctx, key, key_len);
121 SHA256_Update(&alt_ctx, salt, salt_len);
124 SHA256_Update(&alt_ctx, key, key_len);
126 /* Now get result of this (32 bytes) and add it to the other context. */
127 SHA256_Final(alt_result, &alt_ctx);
129 /* Add for any character in the key one byte of the alternate sum. */
130 for (cnt = key_len; cnt > 32; cnt -= 32)
131 SHA256_Update(&ctx, alt_result, 32);
132 SHA256_Update(&ctx, alt_result, cnt);
134 /* Take the binary representation of the length of the key and for
135 * every 1 add the alternate sum, for every 0 the key. */
136 for (cnt = key_len; cnt > 0; cnt >>= 1)
138 SHA256_Update(&ctx, alt_result, 32);
140 SHA256_Update(&ctx, key, key_len);
142 /* Create intermediate result. */
143 SHA256_Final(alt_result, &ctx);
145 /* Start computation of P byte sequence. */
146 SHA256_Init(&alt_ctx);
148 /* For every character in the password add the entire password. */
149 for (cnt = 0; cnt < key_len; ++cnt)
150 SHA256_Update(&alt_ctx, key, key_len);
152 /* Finish the digest. */
153 SHA256_Final(temp_result, &alt_ctx);
155 /* Create byte sequence P. */
156 cp = p_bytes = alloca(key_len);
157 for (cnt = key_len; cnt >= 32; cnt -= 32) {
158 memcpy(cp, temp_result, 32);
161 memcpy(cp, temp_result, cnt);
163 /* Start computation of S byte sequence. */
164 SHA256_Init(&alt_ctx);
166 /* For every character in the password add the entire password. */
167 for (cnt = 0; cnt < 16 + alt_result[0]; ++cnt)
168 SHA256_Update(&alt_ctx, salt, salt_len);
170 /* Finish the digest. */
171 SHA256_Final(temp_result, &alt_ctx);
173 /* Create byte sequence S. */
174 cp = s_bytes = alloca(salt_len);
175 for (cnt = salt_len; cnt >= 32; cnt -= 32) {
176 memcpy(cp, temp_result, 32);
179 memcpy(cp, temp_result, cnt);
181 /* Repeatedly run the collected hash value through SHA256 to burn CPU
183 for (cnt = 0; cnt < rounds; ++cnt) {
187 /* Add key or last result. */
189 SHA256_Update(&ctx, p_bytes, key_len);
191 SHA256_Update(&ctx, alt_result, 32);
193 /* Add salt for numbers not divisible by 3. */
195 SHA256_Update(&ctx, s_bytes, salt_len);
197 /* Add key for numbers not divisible by 7. */
199 SHA256_Update(&ctx, p_bytes, key_len);
201 /* Add key or last result. */
203 SHA256_Update(&ctx, alt_result, 32);
205 SHA256_Update(&ctx, p_bytes, key_len);
207 /* Create intermediate result. */
208 SHA256_Final(alt_result, &ctx);
211 /* Now we can construct the result string. It consists of three
213 cp = stpncpy(buffer, sha256_salt_prefix, MAX(0, buflen));
214 buflen -= sizeof(sha256_salt_prefix) - 1;
217 n = snprintf(cp, MAX(0, buflen), "%s%zu$",
218 sha256_rounds_prefix, rounds);
224 cp = stpncpy(cp, salt, MIN((size_t)MAX(0, buflen), salt_len));
225 buflen -= MIN((size_t)MAX(0, buflen), salt_len);
232 b64_from_24bit(alt_result[0], alt_result[10], alt_result[20], 4, &buflen, &cp);
233 b64_from_24bit(alt_result[21], alt_result[1], alt_result[11], 4, &buflen, &cp);
234 b64_from_24bit(alt_result[12], alt_result[22], alt_result[2], 4, &buflen, &cp);
235 b64_from_24bit(alt_result[3], alt_result[13], alt_result[23], 4, &buflen, &cp);
236 b64_from_24bit(alt_result[24], alt_result[4], alt_result[14], 4, &buflen, &cp);
237 b64_from_24bit(alt_result[15], alt_result[25], alt_result[5], 4, &buflen, &cp);
238 b64_from_24bit(alt_result[6], alt_result[16], alt_result[26], 4, &buflen, &cp);
239 b64_from_24bit(alt_result[27], alt_result[7], alt_result[17], 4, &buflen, &cp);
240 b64_from_24bit(alt_result[18], alt_result[28], alt_result[8], 4, &buflen, &cp);
241 b64_from_24bit(alt_result[9], alt_result[19], alt_result[29], 4, &buflen, &cp);
242 b64_from_24bit(0, alt_result[31], alt_result[30], 3, &buflen, &cp);
248 *cp = '\0'; /* Terminate the string. */
250 /* Clear the buffer for the intermediate result so that people
251 * attaching to processes or reading core dumps cannot get any
252 * information. We do it in this way to clear correct_words[] inside
253 * the SHA256 implementation as well. */
255 SHA256_Final(alt_result, &ctx);
256 memset(temp_result, '\0', sizeof(temp_result));
257 memset(p_bytes, '\0', key_len);
258 memset(s_bytes, '\0', salt_len);
259 memset(&ctx, '\0', sizeof(ctx));
260 memset(&alt_ctx, '\0', sizeof(alt_ctx));
261 if (copied_key != NULL)
262 memset(copied_key, '\0', key_len);
263 if (copied_salt != NULL)
264 memset(copied_salt, '\0', salt_len);
269 /* This entry point is equivalent to crypt(3). */
271 crypt_sha256(const char *key, const char *salt)
273 /* We don't want to have an arbitrary limit in the size of the
274 * password. We can compute an upper bound for the size of the
275 * result in advance and so we can prepare the buffer we pass to
276 * `crypt_sha256_r'. */
282 needed = (sizeof(sha256_salt_prefix) - 1
283 + sizeof(sha256_rounds_prefix) + 9 + 1
284 + strlen(salt) + 1 + 43 + 1);
286 if (buflen < needed) {
287 new_buffer = (char *)realloc(buffer, needed);
289 if (new_buffer == NULL)
296 return crypt_sha256_r(key, salt, buffer, buflen);
301 static const struct {
303 const char result[32];
306 /* Test vectors from FIPS 180-2: appendix B.1. */
309 "\xba\x78\x16\xbf\x8f\x01\xcf\xea\x41\x41\x40\xde\x5d\xae\x22\x23"
310 "\xb0\x03\x61\xa3\x96\x17\x7a\x9c\xb4\x10\xff\x61\xf2\x00\x15\xad"
312 /* Test vectors from FIPS 180-2: appendix B.2. */
314 "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
315 "\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39"
316 "\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1"
318 /* Test vectors from the NESSIE project. */
321 "\xe3\xb0\xc4\x42\x98\xfc\x1c\x14\x9a\xfb\xf4\xc8\x99\x6f\xb9\x24"
322 "\x27\xae\x41\xe4\x64\x9b\x93\x4c\xa4\x95\x99\x1b\x78\x52\xb8\x55"
326 "\xca\x97\x81\x12\xca\x1b\xbd\xca\xfa\xc2\x31\xb3\x9a\x23\xdc\x4d"
327 "\xa7\x86\xef\xf8\x14\x7c\x4e\x72\xb9\x80\x77\x85\xaf\xee\x48\xbb"
331 "\xf7\x84\x6f\x55\xcf\x23\xe1\x4e\xeb\xea\xb5\xb4\xe1\x55\x0c\xad"
332 "\x5b\x50\x9e\x33\x48\xfb\xc4\xef\xa3\xa1\x41\x3d\x39\x3c\xb6\x50"
335 "abcdefghijklmnopqrstuvwxyz",
336 "\x71\xc4\x80\xdf\x93\xd6\xae\x2f\x1e\xfa\xd1\x44\x7c\x66\xc9\x52"
337 "\x5e\x31\x62\x18\xcf\x51\xfc\x8d\x9e\xd8\x32\xf2\xda\xf1\x8b\x73"
340 "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
341 "\x24\x8d\x6a\x61\xd2\x06\x38\xb8\xe5\xc0\x26\x93\x0c\x3e\x60\x39"
342 "\xa3\x3c\xe4\x59\x64\xff\x21\x67\xf6\xec\xed\xd4\x19\xdb\x06\xc1"
345 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
346 "\xdb\x4b\xfc\xbd\x4d\xa0\xcd\x85\xa6\x0c\x3c\x37\xd3\xfb\xd8\x80"
347 "\x5c\x77\xf1\x5f\xc6\xb1\xfd\xfe\x61\x4e\xe0\xa7\xc8\xfd\xb4\xc0"
350 "123456789012345678901234567890123456789012345678901234567890"
351 "12345678901234567890",
352 "\xf3\x71\xbc\x4a\x31\x1f\x2b\x00\x9e\xef\x95\x2d\xd8\x3c\xa8\x0e"
353 "\x2b\x60\x02\x6c\x8e\x93\x55\x92\xd0\xf9\xc3\x08\x45\x3c\x81\x3e"
357 #define ntests (sizeof (tests) / sizeof (tests[0]))
359 static const struct {
362 const char *expected;
366 "$5$saltstring", "Hello world!",
367 "$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5"
370 "$5$rounds=10000$saltstringsaltstring", "Hello world!",
371 "$5$rounds=10000$saltstringsaltst$3xv.VbSHBb41AL9AvLeujZkZRBAwqFMz2."
375 "$5$rounds=5000$toolongsaltstring", "This is just a test",
376 "$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8"
380 "$5$rounds=1400$anotherlongsaltstring",
381 "a very much longer text to encrypt. This one even stretches over more"
383 "$5$rounds=1400$anotherlongsalts$Rx.j8H.h8HjEDGomFU8bDkXm3XIUnzyxf12"
387 "$5$rounds=77777$short",
388 "we have a short salt string but not a short password",
389 "$5$rounds=77777$short$JiO1O3ZpDAxGJeaDIuqCoEFysAe1mZNJRs3pw0KQRd/"
392 "$5$rounds=123456$asaltof16chars..", "a short string",
393 "$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/"
397 "$5$rounds=10$roundstoolow", "the minimum number is still observed",
398 "$5$rounds=1000$roundstoolow$yfvwcWrQ8l/K0DAWyuPMDNHpIVlTQebY9l/gL97"
403 #define ntests2 (sizeof (tests2) / sizeof (tests2[0]))
413 for (cnt = 0; cnt < (int)ntests; ++cnt) {
415 SHA256_Update(&ctx, tests[cnt].input, strlen(tests[cnt].input));
416 SHA256_Final(sum, &ctx);
417 if (memcmp(tests[cnt].result, sum, 32) != 0) {
418 for (i = 0; i < 32; i++)
419 printf("%02X", tests[cnt].result[i]);
421 for (i = 0; i < 32; i++)
422 printf("%02X", sum[i]);
424 printf("test %d run %d failed\n", cnt, 1);
429 for (i = 0; tests[cnt].input[i] != '\0'; ++i)
430 SHA256_Update(&ctx, &tests[cnt].input[i], 1);
431 SHA256_Final(sum, &ctx);
432 if (memcmp(tests[cnt].result, sum, 32) != 0) {
433 for (i = 0; i < 32; i++)
434 printf("%02X", tests[cnt].result[i]);
436 for (i = 0; i < 32; i++)
437 printf("%02X", sum[i]);
439 printf("test %d run %d failed\n", cnt, 2);
444 /* Test vector from FIPS 180-2: appendix B.3. */
447 memset(buf, 'a', sizeof(buf));
449 for (i = 0; i < 1000; ++i)
450 SHA256_Update(&ctx, buf, sizeof(buf));
451 SHA256_Final(sum, &ctx);
452 static const char expected[32] =
453 "\xcd\xc7\x6e\x5c\x99\x14\xfb\x92\x81\xa1\xc7\xe2\x84\xd7\x3e\x67"
454 "\xf1\x80\x9a\x48\xa4\x97\x20\x0e\x04\x6d\x39\xcc\xc7\x11\x2c\xd0";
456 if (memcmp(expected, sum, 32) != 0) {
457 printf("test %d failed\n", cnt);
461 for (cnt = 0; cnt < ntests2; ++cnt) {
462 char *cp = crypt_sha256(tests2[cnt].input, tests2[cnt].salt);
464 if (strcmp(cp, tests2[cnt].expected) != 0) {
465 printf("test %d: expected \"%s\", got \"%s\"\n",
466 cnt, tests2[cnt].expected, cp);
472 puts("all tests OK");