1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 * SHA512-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 <sha512.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 SHA512 "encryption" replacement. */
50static const char sha512_salt_prefix[] = "$6$";
51
52/* Prefix for optional rounds specification. */
53static const char sha512_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
64int
65crypt_sha512(const char *key, const char *salt, char *buffer)
66{
67	u_long srounds;
68	uint8_t alt_result[64], temp_result[64];
69	SHA512_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(sha512_salt_prefix, salt, sizeof(sha512_salt_prefix) - 1) == 0)
82		/* Skip salt prefix. */
83		salt += sizeof(sha512_salt_prefix) - 1;
84
85	if (strncmp(salt, sha512_rounds_prefix, sizeof(sha512_rounds_prefix) - 1)
86	    == 0) {
87		num = salt + sizeof(sha512_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	SHA512_Init(&ctx);
102
103	/* Add the key string. */
104	SHA512_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	SHA512_Update(&ctx, salt, salt_len);
110
111	/* Compute alternate SHA512 sum with input KEY, SALT, and KEY. The
112	 * final result will be added to the first context. */
113	SHA512_Init(&alt_ctx);
114
115	/* Add key. */
116	SHA512_Update(&alt_ctx, key, key_len);
117
118	/* Add salt. */
119	SHA512_Update(&alt_ctx, salt, salt_len);
120
121	/* Add key again. */
122	SHA512_Update(&alt_ctx, key, key_len);
123
124	/* Now get result of this (64 bytes) and add it to the other context. */
125	SHA512_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 > 64; cnt -= 64)
129		SHA512_Update(&ctx, alt_result, 64);
130	SHA512_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			SHA512_Update(&ctx, alt_result, 64);
137		else
138			SHA512_Update(&ctx, key, key_len);
139
140	/* Create intermediate result. */
141	SHA512_Final(alt_result, &ctx);
142
143	/* Start computation of P byte sequence. */
144	SHA512_Init(&alt_ctx);
145
146	/* For every character in the password add the entire password. */
147	for (cnt = 0; cnt < key_len; ++cnt)
148		SHA512_Update(&alt_ctx, key, key_len);
149
150	/* Finish the digest. */
151	SHA512_Final(temp_result, &alt_ctx);
152
153	/* Create byte sequence P. */
154	cp = p_bytes = alloca(key_len);
155	for (cnt = key_len; cnt >= 64; cnt -= 64) {
156		memcpy(cp, temp_result, 64);
157		cp += 64;
158	}
159	memcpy(cp, temp_result, cnt);
160
161	/* Start computation of S byte sequence. */
162	SHA512_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		SHA512_Update(&alt_ctx, salt, salt_len);
167
168	/* Finish the digest. */
169	SHA512_Final(temp_result, &alt_ctx);
170
171	/* Create byte sequence S. */
172	cp = s_bytes = alloca(salt_len);
173	for (cnt = salt_len; cnt >= 64; cnt -= 64) {
174		memcpy(cp, temp_result, 64);
175		cp += 64;
176	}
177	memcpy(cp, temp_result, cnt);
178
179	/* Repeatedly run the collected hash value through SHA512 to burn CPU
180	 * cycles. */
181	for (cnt = 0; cnt < rounds; ++cnt) {
182		/* New context. */
183		SHA512_Init(&ctx);
184
185		/* Add key or last result. */
186		if ((cnt & 1) != 0)
187			SHA512_Update(&ctx, p_bytes, key_len);
188		else
189			SHA512_Update(&ctx, alt_result, 64);
190
191		/* Add salt for numbers not divisible by 3. */
192		if (cnt % 3 != 0)
193			SHA512_Update(&ctx, s_bytes, salt_len);
194
195		/* Add key for numbers not divisible by 7. */
196		if (cnt % 7 != 0)
197			SHA512_Update(&ctx, p_bytes, key_len);
198
199		/* Add key or last result. */
200		if ((cnt & 1) != 0)
201			SHA512_Update(&ctx, alt_result, 64);
202		else
203			SHA512_Update(&ctx, p_bytes, key_len);
204
205		/* Create intermediate result. */
206		SHA512_Final(alt_result, &ctx);
207	}
208
209	/* Now we can construct the result string. It consists of three
210	 * parts. */
211	cp = stpcpy(buffer, sha512_salt_prefix);
212
213	if (rounds_custom)
214		cp += sprintf(cp, "%s%zu$", sha512_rounds_prefix, rounds);
215
216	cp = stpncpy(cp, salt, salt_len);
217
218	*cp++ = '$';
219
220	b64_from_24bit(alt_result[0], alt_result[21], alt_result[42], 4, &cp);
221	b64_from_24bit(alt_result[22], alt_result[43], alt_result[1], 4, &cp);
222	b64_from_24bit(alt_result[44], alt_result[2], alt_result[23], 4, &cp);
223	b64_from_24bit(alt_result[3], alt_result[24], alt_result[45], 4, &cp);
224	b64_from_24bit(alt_result[25], alt_result[46], alt_result[4], 4, &cp);
225	b64_from_24bit(alt_result[47], alt_result[5], alt_result[26], 4, &cp);
226	b64_from_24bit(alt_result[6], alt_result[27], alt_result[48], 4, &cp);
227	b64_from_24bit(alt_result[28], alt_result[49], alt_result[7], 4, &cp);
228	b64_from_24bit(alt_result[50], alt_result[8], alt_result[29], 4, &cp);
229	b64_from_24bit(alt_result[9], alt_result[30], alt_result[51], 4, &cp);
230	b64_from_24bit(alt_result[31], alt_result[52], alt_result[10], 4, &cp);
231	b64_from_24bit(alt_result[53], alt_result[11], alt_result[32], 4, &cp);
232	b64_from_24bit(alt_result[12], alt_result[33], alt_result[54], 4, &cp);
233	b64_from_24bit(alt_result[34], alt_result[55], alt_result[13], 4, &cp);
234	b64_from_24bit(alt_result[56], alt_result[14], alt_result[35], 4, &cp);
235	b64_from_24bit(alt_result[15], alt_result[36], alt_result[57], 4, &cp);
236	b64_from_24bit(alt_result[37], alt_result[58], alt_result[16], 4, &cp);
237	b64_from_24bit(alt_result[59], alt_result[17], alt_result[38], 4, &cp);
238	b64_from_24bit(alt_result[18], alt_result[39], alt_result[60], 4, &cp);
239	b64_from_24bit(alt_result[40], alt_result[61], alt_result[19], 4, &cp);
240	b64_from_24bit(alt_result[62], alt_result[20], alt_result[41], 4, &cp);
241	b64_from_24bit(0, 0, alt_result[63], 2, &cp);
242
243	*cp = '\0';	/* Terminate the string. */
244
245	/* Clear the buffer for the intermediate result so that people
246	 * attaching to processes or reading core dumps cannot get any
247	 * information. We do it in this way to clear correct_words[] inside
248	 * the SHA512 implementation as well. */
249	SHA512_Init(&ctx);
250	SHA512_Final(alt_result, &ctx);
251	memset(temp_result, '\0', sizeof(temp_result));
252	memset(p_bytes, '\0', key_len);
253	memset(s_bytes, '\0', salt_len);
254
255	return (0);
256}
257
258#ifdef TEST
259
260static const struct {
261	const char *input;
262	const char result[64];
263} tests[] =
264{
265	/* Test vectors from FIPS 180-2: appendix C.1. */
266	{
267		"abc",
268		"\xdd\xaf\x35\xa1\x93\x61\x7a\xba\xcc\x41\x73\x49\xae\x20\x41\x31"
269		"\x12\xe6\xfa\x4e\x89\xa9\x7e\xa2\x0a\x9e\xee\xe6\x4b\x55\xd3\x9a"
270		"\x21\x92\x99\x2a\x27\x4f\xc1\xa8\x36\xba\x3c\x23\xa3\xfe\xeb\xbd"
271		"\x45\x4d\x44\x23\x64\x3c\xe8\x0e\x2a\x9a\xc9\x4f\xa5\x4c\xa4\x9f"
272	},
273	/* Test vectors from FIPS 180-2: appendix C.2. */
274	{
275		"abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmn"
276		"hijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu",
277		"\x8e\x95\x9b\x75\xda\xe3\x13\xda\x8c\xf4\xf7\x28\x14\xfc\x14\x3f"
278		"\x8f\x77\x79\xc6\xeb\x9f\x7f\xa1\x72\x99\xae\xad\xb6\x88\x90\x18"
279		"\x50\x1d\x28\x9e\x49\x00\xf7\xe4\x33\x1b\x99\xde\xc4\xb5\x43\x3a"
280		"\xc7\xd3\x29\xee\xb6\xdd\x26\x54\x5e\x96\xe5\x5b\x87\x4b\xe9\x09"
281	},
282	/* Test vectors from the NESSIE project. */
283	{
284		"",
285		"\xcf\x83\xe1\x35\x7e\xef\xb8\xbd\xf1\x54\x28\x50\xd6\x6d\x80\x07"
286		"\xd6\x20\xe4\x05\x0b\x57\x15\xdc\x83\xf4\xa9\x21\xd3\x6c\xe9\xce"
287		"\x47\xd0\xd1\x3c\x5d\x85\xf2\xb0\xff\x83\x18\xd2\x87\x7e\xec\x2f"
288		"\x63\xb9\x31\xbd\x47\x41\x7a\x81\xa5\x38\x32\x7a\xf9\x27\xda\x3e"
289	},
290	{
291		"a",
292		"\x1f\x40\xfc\x92\xda\x24\x16\x94\x75\x09\x79\xee\x6c\xf5\x82\xf2"
293		"\xd5\xd7\xd2\x8e\x18\x33\x5d\xe0\x5a\xbc\x54\xd0\x56\x0e\x0f\x53"
294		"\x02\x86\x0c\x65\x2b\xf0\x8d\x56\x02\x52\xaa\x5e\x74\x21\x05\x46"
295		"\xf3\x69\xfb\xbb\xce\x8c\x12\xcf\xc7\x95\x7b\x26\x52\xfe\x9a\x75"
296	},
297	{
298		"message digest",
299		"\x10\x7d\xbf\x38\x9d\x9e\x9f\x71\xa3\xa9\x5f\x6c\x05\x5b\x92\x51"
300		"\xbc\x52\x68\xc2\xbe\x16\xd6\xc1\x34\x92\xea\x45\xb0\x19\x9f\x33"
301		"\x09\xe1\x64\x55\xab\x1e\x96\x11\x8e\x8a\x90\x5d\x55\x97\xb7\x20"
302		"\x38\xdd\xb3\x72\xa8\x98\x26\x04\x6d\xe6\x66\x87\xbb\x42\x0e\x7c"
303	},
304	{
305		"abcdefghijklmnopqrstuvwxyz",
306		"\x4d\xbf\xf8\x6c\xc2\xca\x1b\xae\x1e\x16\x46\x8a\x05\xcb\x98\x81"
307		"\xc9\x7f\x17\x53\xbc\xe3\x61\x90\x34\x89\x8f\xaa\x1a\xab\xe4\x29"
308		"\x95\x5a\x1b\xf8\xec\x48\x3d\x74\x21\xfe\x3c\x16\x46\x61\x3a\x59"
309		"\xed\x54\x41\xfb\x0f\x32\x13\x89\xf7\x7f\x48\xa8\x79\xc7\xb1\xf1"
310	},
311	{
312		"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
313		"\x20\x4a\x8f\xc6\xdd\xa8\x2f\x0a\x0c\xed\x7b\xeb\x8e\x08\xa4\x16"
314		"\x57\xc1\x6e\xf4\x68\xb2\x28\xa8\x27\x9b\xe3\x31\xa7\x03\xc3\x35"
315		"\x96\xfd\x15\xc1\x3b\x1b\x07\xf9\xaa\x1d\x3b\xea\x57\x78\x9c\xa0"
316		"\x31\xad\x85\xc7\xa7\x1d\xd7\x03\x54\xec\x63\x12\x38\xca\x34\x45"
317	},
318	{
319		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
320		"\x1e\x07\xbe\x23\xc2\x6a\x86\xea\x37\xea\x81\x0c\x8e\xc7\x80\x93"
321		"\x52\x51\x5a\x97\x0e\x92\x53\xc2\x6f\x53\x6c\xfc\x7a\x99\x96\xc4"
322		"\x5c\x83\x70\x58\x3e\x0a\x78\xfa\x4a\x90\x04\x1d\x71\xa4\xce\xab"
323		"\x74\x23\xf1\x9c\x71\xb9\xd5\xa3\xe0\x12\x49\xf0\xbe\xbd\x58\x94"
324	},
325	{
326		"123456789012345678901234567890123456789012345678901234567890"
327		"12345678901234567890",
328		"\x72\xec\x1e\xf1\x12\x4a\x45\xb0\x47\xe8\xb7\xc7\x5a\x93\x21\x95"
329		"\x13\x5b\xb6\x1d\xe2\x4e\xc0\xd1\x91\x40\x42\x24\x6e\x0a\xec\x3a"
330		"\x23\x54\xe0\x93\xd7\x6f\x30\x48\xb4\x56\x76\x43\x46\x90\x0c\xb1"
331		"\x30\xd2\xa4\xfd\x5d\xd1\x6a\xbb\x5e\x30\xbc\xb8\x50\xde\xe8\x43"
332	}
333};
334
335#define ntests (sizeof (tests) / sizeof (tests[0]))
336
337static const struct {
338	const char *salt;
339	const char *input;
340	const char *expected;
341} tests2[] =
342{
343	{
344		"$6$saltstring", "Hello world!",
345		"$6$saltstring$svn8UoSVapNtMuq1ukKS4tPQd8iKwSMHWjl/O817G3uBnIFNjnQJu"
346		"esI68u4OTLiBFdcbYEdFCoEOfaS35inz1"
347	},
348	{
349		"$6$rounds=10000$saltstringsaltstring", "Hello world!",
350		"$6$rounds=10000$saltstringsaltst$OW1/O6BYHV6BcXZu8QVeXbDWra3Oeqh0sb"
351		"HbbMCVNSnCM/UrjmM0Dp8vOuZeHBy/YTBmSK6H9qs/y3RnOaw5v."
352	},
353	{
354		"$6$rounds=5000$toolongsaltstring", "This is just a test",
355		"$6$rounds=5000$toolongsaltstrin$lQ8jolhgVRVhY4b5pZKaysCLi0QBxGoNeKQ"
356		"zQ3glMhwllF7oGDZxUhx1yxdYcz/e1JSbq3y6JMxxl8audkUEm0"
357	},
358	{
359		"$6$rounds=1400$anotherlongsaltstring",
360		"a very much longer text to encrypt.  This one even stretches over more"
361		"than one line.",
362		"$6$rounds=1400$anotherlongsalts$POfYwTEok97VWcjxIiSOjiykti.o/pQs.wP"
363		"vMxQ6Fm7I6IoYN3CmLs66x9t0oSwbtEW7o7UmJEiDwGqd8p4ur1"
364	},
365	{
366		"$6$rounds=77777$short",
367		"we have a short salt string but not a short password",
368		"$6$rounds=77777$short$WuQyW2YR.hBNpjjRhpYD/ifIw05xdfeEyQoMxIXbkvr0g"
369		"ge1a1x3yRULJ5CCaUeOxFmtlcGZelFl5CxtgfiAc0"
370	},
371	{
372		"$6$rounds=123456$asaltof16chars..", "a short string",
373		"$6$rounds=123456$asaltof16chars..$BtCwjqMJGx5hrJhZywWvt0RLE8uZ4oPwc"
374		"elCjmw2kSYu.Ec6ycULevoBK25fs2xXgMNrCzIMVcgEJAstJeonj1"
375	},
376	{
377		"$6$rounds=10$roundstoolow", "the minimum number is still observed",
378		"$6$rounds=1000$roundstoolow$kUMsbe306n21p9R.FRkW3IGn.S9NPN0x50YhH1x"
379		"hLsPuWGsUSklZt58jaTfF4ZEQpyUNGc0dqbpBYYBaHHrsX."
380	},
381};
382
383#define ntests2 (sizeof (tests2) / sizeof (tests2[0]))
384
385int
386main(void)
387{
388	SHA512_CTX ctx;
389	uint8_t sum[64];
390	int result = 0;
391	int i, cnt;
392
393	for (cnt = 0; cnt < (int)ntests; ++cnt) {
394		SHA512_Init(&ctx);
395		SHA512_Update(&ctx, tests[cnt].input, strlen(tests[cnt].input));
396		SHA512_Final(sum, &ctx);
397		if (memcmp(tests[cnt].result, sum, 64) != 0) {
398			printf("test %d run %d failed\n", cnt, 1);
399			result = 1;
400		}
401
402		SHA512_Init(&ctx);
403		for (i = 0; tests[cnt].input[i] != '\0'; ++i)
404			SHA512_Update(&ctx, &tests[cnt].input[i], 1);
405		SHA512_Final(sum, &ctx);
406		if (memcmp(tests[cnt].result, sum, 64) != 0) {
407			printf("test %d run %d failed\n", cnt, 2);
408			result = 1;
409		}
410	}
411
412	/* Test vector from FIPS 180-2: appendix C.3. */
413	char buf[1000];
414
415	memset(buf, 'a', sizeof(buf));
416	SHA512_Init(&ctx);
417	for (i = 0; i < 1000; ++i)
418		SHA512_Update(&ctx, buf, sizeof(buf));
419	SHA512_Final(sum, &ctx);
420	static const char expected[64] =
421	"\xe7\x18\x48\x3d\x0c\xe7\x69\x64\x4e\x2e\x42\xc7\xbc\x15\xb4\x63"
422	"\x8e\x1f\x98\xb1\x3b\x20\x44\x28\x56\x32\xa8\x03\xaf\xa9\x73\xeb"
423	"\xde\x0f\xf2\x44\x87\x7e\xa6\x0a\x4c\xb0\x43\x2c\xe5\x77\xc3\x1b"
424	"\xeb\x00\x9c\x5c\x2c\x49\xaa\x2e\x4e\xad\xb2\x17\xad\x8c\xc0\x9b";
425
426	if (memcmp(expected, sum, 64) != 0) {
427		printf("test %d failed\n", cnt);
428		result = 1;
429	}
430
431	for (cnt = 0; cnt < ntests2; ++cnt) {
432		char *cp = crypt_sha512(tests2[cnt].input, tests2[cnt].salt);
433
434		if (strcmp(cp, tests2[cnt].expected) != 0) {
435			printf("test %d: expected \"%s\", got \"%s\"\n",
436			       cnt, tests2[cnt].expected, cp);
437			result = 1;
438		}
439	}
440
441	if (result == 0)
442		puts("all tests OK");
443
444	return result;
445}
446
447#endif /* TEST */
448