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(const char *key, const char *salt, char *buffer)
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;
76 /* Default number of rounds. */
77 rounds = ROUNDS_DEFAULT;
78 rounds_custom = false;
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;
86 if (strncmp(salt, sha256_rounds_prefix, sizeof(sha256_rounds_prefix) - 1)
88 num = salt + sizeof(sha256_rounds_prefix) - 1;
89 srounds = strtoul(num, &endp, 10);
93 rounds = MAX(ROUNDS_MIN, MIN(srounds, ROUNDS_MAX));
98 salt_len = MIN(strcspn(salt, "$"), SALT_LEN_MAX);
99 key_len = strlen(key);
101 /* Prepare for the real work. */
104 /* Add the key string. */
105 SHA256_Update(&ctx, key, key_len);
107 /* The last part is the salt string. This must be at most 8
108 * characters and it ends at the first `$' character (for
109 * compatibility with existing implementations). */
110 SHA256_Update(&ctx, salt, salt_len);
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);
117 SHA256_Update(&alt_ctx, key, key_len);
120 SHA256_Update(&alt_ctx, salt, salt_len);
123 SHA256_Update(&alt_ctx, key, key_len);
125 /* Now get result of this (32 bytes) and add it to the other context. */
126 SHA256_Final(alt_result, &alt_ctx);
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);
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)
137 SHA256_Update(&ctx, alt_result, 32);
139 SHA256_Update(&ctx, key, key_len);
141 /* Create intermediate result. */
142 SHA256_Final(alt_result, &ctx);
144 /* Start computation of P byte sequence. */
145 SHA256_Init(&alt_ctx);
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);
151 /* Finish the digest. */
152 SHA256_Final(temp_result, &alt_ctx);
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);
160 memcpy(cp, temp_result, cnt);
162 /* Start computation of S byte sequence. */
163 SHA256_Init(&alt_ctx);
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);
169 /* Finish the digest. */
170 SHA256_Final(temp_result, &alt_ctx);
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);
178 memcpy(cp, temp_result, cnt);
180 /* Repeatedly run the collected hash value through SHA256 to burn CPU
182 for (cnt = 0; cnt < rounds; ++cnt) {
186 /* Add key or last result. */
188 SHA256_Update(&ctx, p_bytes, key_len);
190 SHA256_Update(&ctx, alt_result, 32);
192 /* Add salt for numbers not divisible by 3. */
194 SHA256_Update(&ctx, s_bytes, salt_len);
196 /* Add key for numbers not divisible by 7. */
198 SHA256_Update(&ctx, p_bytes, key_len);
200 /* Add key or last result. */
202 SHA256_Update(&ctx, alt_result, 32);
204 SHA256_Update(&ctx, p_bytes, key_len);
206 /* Create intermediate result. */
207 SHA256_Final(alt_result, &ctx);
210 /* Now we can construct the result string. It consists of three
212 cp = stpcpy(buffer, sha256_salt_prefix);
215 cp += sprintf(cp, "%s%zu$", sha256_rounds_prefix, rounds);
217 cp = stpncpy(cp, salt, salt_len);
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. */
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. */
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);
255 static const struct {
257 const char result[32];
260 /* Test vectors from FIPS 180-2: appendix B.1. */
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"
266 /* Test vectors from FIPS 180-2: appendix B.2. */
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"
272 /* Test vectors from the NESSIE project. */
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"
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"
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"
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"
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"
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"
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"
311 #define ntests (sizeof (tests) / sizeof (tests[0]))
313 static const struct {
316 const char *expected;
320 "$5$saltstring", "Hello world!",
321 "$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5"
324 "$5$rounds=10000$saltstringsaltstring", "Hello world!",
325 "$5$rounds=10000$saltstringsaltst$3xv.VbSHBb41AL9AvLeujZkZRBAwqFMz2."
329 "$5$rounds=5000$toolongsaltstring", "This is just a test",
330 "$5$rounds=5000$toolongsaltstrin$Un/5jzAHMgOGZ5.mWJpuVolil07guHPvOW8"
334 "$5$rounds=1400$anotherlongsaltstring",
335 "a very much longer text to encrypt. This one even stretches over more"
337 "$5$rounds=1400$anotherlongsalts$Rx.j8H.h8HjEDGomFU8bDkXm3XIUnzyxf12"
341 "$5$rounds=77777$short",
342 "we have a short salt string but not a short password",
343 "$5$rounds=77777$short$JiO1O3ZpDAxGJeaDIuqCoEFysAe1mZNJRs3pw0KQRd/"
346 "$5$rounds=123456$asaltof16chars..", "a short string",
347 "$5$rounds=123456$asaltof16chars..$gP3VQ/6X7UUEW3HkBn2w1/Ptq2jxPyzV/"
351 "$5$rounds=10$roundstoolow", "the minimum number is still observed",
352 "$5$rounds=1000$roundstoolow$yfvwcWrQ8l/K0DAWyuPMDNHpIVlTQebY9l/gL97"
357 #define ntests2 (sizeof (tests2) / sizeof (tests2[0]))
367 for (cnt = 0; cnt < (int)ntests; ++cnt) {
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]);
375 for (i = 0; i < 32; i++)
376 printf("%02X", sum[i]);
378 printf("test %d run %d failed\n", cnt, 1);
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]);
390 for (i = 0; i < 32; i++)
391 printf("%02X", sum[i]);
393 printf("test %d run %d failed\n", cnt, 2);
398 /* Test vector from FIPS 180-2: appendix B.3. */
401 memset(buf, 'a', sizeof(buf));
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";
410 if (memcmp(expected, sum, 32) != 0) {
411 printf("test %d failed\n", cnt);
415 for (cnt = 0; cnt < ntests2; ++cnt) {
416 char *cp = crypt_sha256(tests2[cnt].input, tests2[cnt].salt);
418 if (strcmp(cp, tests2[cnt].expected) != 0) {
419 printf("test %d: expected \"%s\", got \"%s\"\n",
420 cnt, tests2[cnt].expected, cp);
426 puts("all tests OK");