summaryrefslogtreecommitdiff
path: root/src/crypt/crypt_sha512.c
blob: 39970cafe87154ddddac5238d2ba3ff2c62859a5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
/*
 * public domain sha512 crypt implementation
 *
 * original sha crypt design: http://people.redhat.com/drepper/SHA-crypt.txt
 * in this implementation at least 32bit int is assumed,
 * key length is limited, the $6$ prefix is mandatory, '\n' and ':' is rejected
 * in the salt and rounds= setting must contain a valid iteration count,
 * on error "*" is returned.
 */
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>

/* public domain sha512 implementation based on fips180-3 */
/* >=2^64 bits messages are not supported (about 2000 peta bytes) */

struct sha512 {
	uint64_t len;     /* processed message length */
	uint64_t h[8];    /* hash state */
	uint8_t buf[128]; /* message block buffer */
};

static uint64_t ror(uint64_t n, int k) { return (n >> k) | (n << (64-k)); }
#define Ch(x,y,z)  (z ^ (x & (y ^ z)))
#define Maj(x,y,z) ((x & y) | (z & (x | y)))
#define S0(x)      (ror(x,28) ^ ror(x,34) ^ ror(x,39))
#define S1(x)      (ror(x,14) ^ ror(x,18) ^ ror(x,41))
#define R0(x)      (ror(x,1) ^ ror(x,8) ^ (x>>7))
#define R1(x)      (ror(x,19) ^ ror(x,61) ^ (x>>6))

static const uint64_t K[80] = {
0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL, 0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
0xd807aa98a3030242ULL, 0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL, 0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL, 0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL, 0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
0xd192e819d6ef5218ULL, 0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL, 0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, 0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL, 0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
};

static void processblock(struct sha512 *s, const uint8_t *buf)
{
	uint64_t W[80], t1, t2, a, b, c, d, e, f, g, h;
	int i;

	for (i = 0; i < 16; i++) {
		W[i] = (uint64_t)buf[8*i]<<56;
		W[i] |= (uint64_t)buf[8*i+1]<<48;
		W[i] |= (uint64_t)buf[8*i+2]<<40;
		W[i] |= (uint64_t)buf[8*i+3]<<32;
		W[i] |= (uint64_t)buf[8*i+4]<<24;
		W[i] |= (uint64_t)buf[8*i+5]<<16;
		W[i] |= (uint64_t)buf[8*i+6]<<8;
		W[i] |= buf[8*i+7];
	}
	for (; i < 80; i++)
		W[i] = R1(W[i-2]) + W[i-7] + R0(W[i-15]) + W[i-16];
	a = s->h[0];
	b = s->h[1];
	c = s->h[2];
	d = s->h[3];
	e = s->h[4];
	f = s->h[5];
	g = s->h[6];
	h = s->h[7];
	for (i = 0; i < 80; i++) {
		t1 = h + S1(e) + Ch(e,f,g) + K[i] + W[i];
		t2 = S0(a) + Maj(a,b,c);
		h = g;
		g = f;
		f = e;
		e = d + t1;
		d = c;
		c = b;
		b = a;
		a = t1 + t2;
	}
	s->h[0] += a;
	s->h[1] += b;
	s->h[2] += c;
	s->h[3] += d;
	s->h[4] += e;
	s->h[5] += f;
	s->h[6] += g;
	s->h[7] += h;
}

static void pad(struct sha512 *s)
{
	unsigned r = s->len % 128;

	s->buf[r++] = 0x80;
	if (r > 112) {
		memset(s->buf + r, 0, 128 - r);
		r = 0;
		processblock(s, s->buf);
	}
	memset(s->buf + r, 0, 120 - r);
	s->len *= 8;
	s->buf[120] = s->len >> 56;
	s->buf[121] = s->len >> 48;
	s->buf[122] = s->len >> 40;
	s->buf[123] = s->len >> 32;
	s->buf[124] = s->len >> 24;
	s->buf[125] = s->len >> 16;
	s->buf[126] = s->len >> 8;
	s->buf[127] = s->len;
	processblock(s, s->buf);
}

static void sha512_init(struct sha512 *s)
{
	s->len = 0;
	s->h[0] = 0x6a09e667f3bcc908ULL;
	s->h[1] = 0xbb67ae8584caa73bULL;
	s->h[2] = 0x3c6ef372fe94f82bULL;
	s->h[3] = 0xa54ff53a5f1d36f1ULL;
	s->h[4] = 0x510e527fade682d1ULL;
	s->h[5] = 0x9b05688c2b3e6c1fULL;
	s->h[6] = 0x1f83d9abfb41bd6bULL;
	s->h[7] = 0x5be0cd19137e2179ULL;
}

static void sha512_sum(struct sha512 *s, uint8_t *md)
{
	int i;

	pad(s);
	for (i = 0; i < 8; i++) {
		md[8*i] = s->h[i] >> 56;
		md[8*i+1] = s->h[i] >> 48;
		md[8*i+2] = s->h[i] >> 40;
		md[8*i+3] = s->h[i] >> 32;
		md[8*i+4] = s->h[i] >> 24;
		md[8*i+5] = s->h[i] >> 16;
		md[8*i+6] = s->h[i] >> 8;
		md[8*i+7] = s->h[i];
	}
}

static void sha512_update(struct sha512 *s, const void *m, unsigned long len)
{
	const uint8_t *p = m;
	unsigned r = s->len % 128;

	s->len += len;
	if (r) {
		if (len < 128 - r) {
			memcpy(s->buf + r, p, len);
			return;
		}
		memcpy(s->buf + r, p, 128 - r);
		len -= 128 - r;
		p += 128 - r;
		processblock(s, s->buf);
	}
	for (; len >= 128; len -= 128, p += 128)
		processblock(s, p);
	memcpy(s->buf, p, len);
}

static const unsigned char b64[] =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

static char *to64(char *s, unsigned int u, int n)
{
	while (--n >= 0) {
		*s++ = b64[u % 64];
		u /= 64;
	}
	return s;
}

/* key limit is not part of the original design, added for DoS protection.
 * rounds limit has been lowered (versus the reference/spec), also for DoS
 * protection. runtime is O(klen^2 + klen*rounds) */
#define KEY_MAX 256
#define SALT_MAX 16
#define ROUNDS_DEFAULT 5000
#define ROUNDS_MIN 1000
#define ROUNDS_MAX 9999999

/* hash n bytes of the repeated md message digest */
static void hashmd(struct sha512 *s, unsigned int n, const void *md)
{
	unsigned int i;

	for (i = n; i > 64; i -= 64)
		sha512_update(s, md, 64);
	sha512_update(s, md, i);
}

static char *sha512crypt(const char *key, const char *setting, char *output)
{
	struct sha512 ctx;
	unsigned char md[64], kmd[64], smd[64];
	unsigned int i, r, klen, slen;
	char rounds[20] = "";
	const char *salt;
	char *p;

	/* reject large keys */
	for (i = 0; i <= KEY_MAX && key[i]; i++);
	if (i > KEY_MAX)
		return 0;
	klen = i;

	/* setting: $6$rounds=n$salt$ (rounds=n$ and closing $ are optional) */
	if (strncmp(setting, "$6$", 3) != 0)
		return 0;
	salt = setting + 3;

	r = ROUNDS_DEFAULT;
	if (strncmp(salt, "rounds=", sizeof "rounds=" - 1) == 0) {
		unsigned long u;
		char *end;

		/*
		 * this is a deviation from the reference:
		 * bad rounds setting is rejected if it is
		 * - empty
		 * - unterminated (missing '$')
		 * - begins with anything but a decimal digit
		 * the reference implementation treats these bad
		 * rounds as part of the salt or parse them with
		 * strtoul semantics which may cause problems
		 * including non-portable hashes that depend on
		 * the host's value of ULONG_MAX.
		 */
		salt += sizeof "rounds=" - 1;
		if (!isdigit(*salt))
			return 0;
		u = strtoul(salt, &end, 10);
		if (*end != '$')
			return 0;
		salt = end+1;
		if (u < ROUNDS_MIN)
			r = ROUNDS_MIN;
		else if (u > ROUNDS_MAX)
			return 0;
		else
			r = u;
		/* needed when rounds is zero prefixed or out of bounds */
		sprintf(rounds, "rounds=%u$", r);
	}

	for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++)
		/* reject characters that interfere with /etc/shadow parsing */
		if (salt[i] == '\n' || salt[i] == ':')
			return 0;
	slen = i;

	/* B = sha(key salt key) */
	sha512_init(&ctx);
	sha512_update(&ctx, key, klen);
	sha512_update(&ctx, salt, slen);
	sha512_update(&ctx, key, klen);
	sha512_sum(&ctx, md);

	/* A = sha(key salt repeat-B alternate-B-key) */
	sha512_init(&ctx);
	sha512_update(&ctx, key, klen);
	sha512_update(&ctx, salt, slen);
	hashmd(&ctx, klen, md);
	for (i = klen; i > 0; i >>= 1)
		if (i & 1)
			sha512_update(&ctx, md, sizeof md);
		else
			sha512_update(&ctx, key, klen);
	sha512_sum(&ctx, md);

	/* DP = sha(repeat-key), this step takes O(klen^2) time */
	sha512_init(&ctx);
	for (i = 0; i < klen; i++)
		sha512_update(&ctx, key, klen);
	sha512_sum(&ctx, kmd);

	/* DS = sha(repeat-salt) */
	sha512_init(&ctx);
	for (i = 0; i < 16 + md[0]; i++)
		sha512_update(&ctx, salt, slen);
	sha512_sum(&ctx, smd);

	/* iterate A = f(A,DP,DS), this step takes O(rounds*klen) time */
	for (i = 0; i < r; i++) {
		sha512_init(&ctx);
		if (i % 2)
			hashmd(&ctx, klen, kmd);
		else
			sha512_update(&ctx, md, sizeof md);
		if (i % 3)
			sha512_update(&ctx, smd, slen);
		if (i % 7)
			hashmd(&ctx, klen, kmd);
		if (i % 2)
			sha512_update(&ctx, md, sizeof md);
		else
			hashmd(&ctx, klen, kmd);
		sha512_sum(&ctx, md);
	}

	/* output is $6$rounds=n$salt$hash */
	p = output;
	p += sprintf(p, "$6$%s%.*s$", rounds, slen, salt);
#if 1
	static const unsigned char perm[][3] = {
		0,21,42,22,43,1,44,2,23,3,24,45,25,46,4,
		47,5,26,6,27,48,28,49,7,50,8,29,9,30,51,
		31,52,10,53,11,32,12,33,54,34,55,13,56,14,35,
		15,36,57,37,58,16,59,17,38,18,39,60,40,61,19,
		62,20,41 };
	for (i=0; i<21; i++) p = to64(p,
		(md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
#else
	p = to64(p, (md[0]<<16)|(md[21]<<8)|md[42], 4);
	p = to64(p, (md[22]<<16)|(md[43]<<8)|md[1], 4);
	p = to64(p, (md[44]<<16)|(md[2]<<8)|md[23], 4);
	p = to64(p, (md[3]<<16)|(md[24]<<8)|md[45], 4);
	p = to64(p, (md[25]<<16)|(md[46]<<8)|md[4], 4);
	p = to64(p, (md[47]<<16)|(md[5]<<8)|md[26], 4);
	p = to64(p, (md[6]<<16)|(md[27]<<8)|md[48], 4);
	p = to64(p, (md[28]<<16)|(md[49]<<8)|md[7], 4);
	p = to64(p, (md[50]<<16)|(md[8]<<8)|md[29], 4);
	p = to64(p, (md[9]<<16)|(md[30]<<8)|md[51], 4);
	p = to64(p, (md[31]<<16)|(md[52]<<8)|md[10], 4);
	p = to64(p, (md[53]<<16)|(md[11]<<8)|md[32], 4);
	p = to64(p, (md[12]<<16)|(md[33]<<8)|md[54], 4);
	p = to64(p, (md[34]<<16)|(md[55]<<8)|md[13], 4);
	p = to64(p, (md[56]<<16)|(md[14]<<8)|md[35], 4);
	p = to64(p, (md[15]<<16)|(md[36]<<8)|md[57], 4);
	p = to64(p, (md[37]<<16)|(md[58]<<8)|md[16], 4);
	p = to64(p, (md[59]<<16)|(md[17]<<8)|md[38], 4);
	p = to64(p, (md[18]<<16)|(md[39]<<8)|md[60], 4);
	p = to64(p, (md[40]<<16)|(md[61]<<8)|md[19], 4);
	p = to64(p, (md[62]<<16)|(md[20]<<8)|md[41], 4);
#endif
	p = to64(p, md[63], 2);
	*p = 0;
	return output;
}

char *__crypt_sha512(const char *key, const char *setting, char *output)
{
	static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
	static const char testsetting[] = "$6$rounds=1234$abc0123456789$";
	static const char testhash[] = "$6$rounds=1234$abc0123456789$BCpt8zLrc/RcyuXmCDOE1ALqMXB2MH6n1g891HhFj8.w7LxGv.FTkqq6Vxc/km3Y0jE0j24jY5PIv/oOu6reg1";
	char testbuf[128];
	char *p, *q;

	p = sha512crypt(key, setting, output);
	/* self test and stack cleanup */
	q = sha512crypt(testkey, testsetting, testbuf);
	if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
		return "*";
	return p;
}