crypt_sha512.c raw
1 /*
2 * public domain sha512 crypt implementation
3 *
4 * original sha crypt design: http://people.redhat.com/drepper/SHA-crypt.txt
5 * in this implementation at least 32bit int is assumed,
6 * key length is limited, the $6$ prefix is mandatory, '\n' and ':' is rejected
7 * in the salt and rounds= setting must contain a valid iteration count,
8 * on error "*" is returned.
9 */
10 #include <ctype.h>
11 #include <stdlib.h>
12 #include <stdio.h>
13 #include <string.h>
14 #include <stdint.h>
15
16 /* public domain sha512 implementation based on fips180-3 */
17 /* >=2^64 bits messages are not supported (about 2000 peta bytes) */
18
19 struct sha512 {
20 uint64_t len; /* processed message length */
21 uint64_t h[8]; /* hash state */
22 uint8_t buf[128]; /* message block buffer */
23 };
24
25 static uint64_t ror(uint64_t n, int k) { return (n >> k) | (n << (64-k)); }
26 #define Ch(x,y,z) (z ^ (x & (y ^ z)))
27 #define Maj(x,y,z) ((x & y) | (z & (x | y)))
28 #define S0(x) (ror(x,28) ^ ror(x,34) ^ ror(x,39))
29 #define S1(x) (ror(x,14) ^ ror(x,18) ^ ror(x,41))
30 #define R0(x) (ror(x,1) ^ ror(x,8) ^ (x>>7))
31 #define R1(x) (ror(x,19) ^ ror(x,61) ^ (x>>6))
32
33 static const uint64_t K[80] = {
34 0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
35 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL, 0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
36 0xd807aa98a3030242ULL, 0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
37 0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
38 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL, 0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
39 0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
40 0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
41 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL, 0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
42 0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
43 0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
44 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL, 0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
45 0xd192e819d6ef5218ULL, 0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
46 0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
47 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL, 0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
48 0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
49 0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
50 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, 0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
51 0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
52 0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
53 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL, 0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
54 };
55
56 static void processblock(struct sha512 *s, const uint8_t *buf)
57 {
58 uint64_t W[80], t1, t2, a, b, c, d, e, f, g, h;
59 int i;
60
61 for (i = 0; i < 16; i++) {
62 W[i] = (uint64_t)buf[8*i]<<56;
63 W[i] |= (uint64_t)buf[8*i+1]<<48;
64 W[i] |= (uint64_t)buf[8*i+2]<<40;
65 W[i] |= (uint64_t)buf[8*i+3]<<32;
66 W[i] |= (uint64_t)buf[8*i+4]<<24;
67 W[i] |= (uint64_t)buf[8*i+5]<<16;
68 W[i] |= (uint64_t)buf[8*i+6]<<8;
69 W[i] |= buf[8*i+7];
70 }
71 for (; i < 80; i++)
72 W[i] = R1(W[i-2]) + W[i-7] + R0(W[i-15]) + W[i-16];
73 a = s->h[0];
74 b = s->h[1];
75 c = s->h[2];
76 d = s->h[3];
77 e = s->h[4];
78 f = s->h[5];
79 g = s->h[6];
80 h = s->h[7];
81 for (i = 0; i < 80; i++) {
82 t1 = h + S1(e) + Ch(e,f,g) + K[i] + W[i];
83 t2 = S0(a) + Maj(a,b,c);
84 h = g;
85 g = f;
86 f = e;
87 e = d + t1;
88 d = c;
89 c = b;
90 b = a;
91 a = t1 + t2;
92 }
93 s->h[0] += a;
94 s->h[1] += b;
95 s->h[2] += c;
96 s->h[3] += d;
97 s->h[4] += e;
98 s->h[5] += f;
99 s->h[6] += g;
100 s->h[7] += h;
101 }
102
103 static void pad(struct sha512 *s)
104 {
105 unsigned r = s->len % 128;
106
107 s->buf[r++] = 0x80;
108 if (r > 112) {
109 memset(s->buf + r, 0, 128 - r);
110 r = 0;
111 processblock(s, s->buf);
112 }
113 memset(s->buf + r, 0, 120 - r);
114 s->len *= 8;
115 s->buf[120] = s->len >> 56;
116 s->buf[121] = s->len >> 48;
117 s->buf[122] = s->len >> 40;
118 s->buf[123] = s->len >> 32;
119 s->buf[124] = s->len >> 24;
120 s->buf[125] = s->len >> 16;
121 s->buf[126] = s->len >> 8;
122 s->buf[127] = s->len;
123 processblock(s, s->buf);
124 }
125
126 static void sha512_init(struct sha512 *s)
127 {
128 s->len = 0;
129 s->h[0] = 0x6a09e667f3bcc908ULL;
130 s->h[1] = 0xbb67ae8584caa73bULL;
131 s->h[2] = 0x3c6ef372fe94f82bULL;
132 s->h[3] = 0xa54ff53a5f1d36f1ULL;
133 s->h[4] = 0x510e527fade682d1ULL;
134 s->h[5] = 0x9b05688c2b3e6c1fULL;
135 s->h[6] = 0x1f83d9abfb41bd6bULL;
136 s->h[7] = 0x5be0cd19137e2179ULL;
137 }
138
139 static void sha512_sum(struct sha512 *s, uint8_t *md)
140 {
141 int i;
142
143 pad(s);
144 for (i = 0; i < 8; i++) {
145 md[8*i] = s->h[i] >> 56;
146 md[8*i+1] = s->h[i] >> 48;
147 md[8*i+2] = s->h[i] >> 40;
148 md[8*i+3] = s->h[i] >> 32;
149 md[8*i+4] = s->h[i] >> 24;
150 md[8*i+5] = s->h[i] >> 16;
151 md[8*i+6] = s->h[i] >> 8;
152 md[8*i+7] = s->h[i];
153 }
154 }
155
156 static void sha512_update(struct sha512 *s, const void *m, unsigned long len)
157 {
158 const uint8_t *p = m;
159 unsigned r = s->len % 128;
160
161 s->len += len;
162 if (r) {
163 if (len < 128 - r) {
164 memcpy(s->buf + r, p, len);
165 return;
166 }
167 memcpy(s->buf + r, p, 128 - r);
168 len -= 128 - r;
169 p += 128 - r;
170 processblock(s, s->buf);
171 }
172 for (; len >= 128; len -= 128, p += 128)
173 processblock(s, p);
174 memcpy(s->buf, p, len);
175 }
176
177 static const unsigned char b64[] =
178 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
179
180 static char *to64(char *s, unsigned int u, int n)
181 {
182 while (--n >= 0) {
183 *s++ = b64[u % 64];
184 u /= 64;
185 }
186 return s;
187 }
188
189 /* key limit is not part of the original design, added for DoS protection.
190 * rounds limit has been lowered (versus the reference/spec), also for DoS
191 * protection. runtime is O(klen^2 + klen*rounds) */
192 #define KEY_MAX 256
193 #define SALT_MAX 16
194 #define ROUNDS_DEFAULT 5000
195 #define ROUNDS_MIN 1000
196 #define ROUNDS_MAX 9999999
197
198 /* hash n bytes of the repeated md message digest */
199 static void hashmd(struct sha512 *s, unsigned int n, const void *md)
200 {
201 unsigned int i;
202
203 for (i = n; i > 64; i -= 64)
204 sha512_update(s, md, 64);
205 sha512_update(s, md, i);
206 }
207
208 static char *sha512crypt(const char *key, const char *setting, char *output)
209 {
210 struct sha512 ctx;
211 unsigned char md[64], kmd[64], smd[64];
212 unsigned int i, r, klen, slen;
213 char rounds[20] = "";
214 const char *salt;
215 char *p;
216
217 /* reject large keys */
218 for (i = 0; i <= KEY_MAX && key[i]; i++);
219 if (i > KEY_MAX)
220 return 0;
221 klen = i;
222
223 /* setting: $6$rounds=n$salt$ (rounds=n$ and closing $ are optional) */
224 if (strncmp(setting, "$6$", 3) != 0)
225 return 0;
226 salt = setting + 3;
227
228 r = ROUNDS_DEFAULT;
229 if (strncmp(salt, "rounds=", sizeof "rounds=" - 1) == 0) {
230 unsigned long u;
231 char *end;
232
233 /*
234 * this is a deviation from the reference:
235 * bad rounds setting is rejected if it is
236 * - empty
237 * - unterminated (missing '$')
238 * - begins with anything but a decimal digit
239 * the reference implementation treats these bad
240 * rounds as part of the salt or parse them with
241 * strtoul semantics which may cause problems
242 * including non-portable hashes that depend on
243 * the host's value of ULONG_MAX.
244 */
245 salt += sizeof "rounds=" - 1;
246 if (!isdigit(*salt))
247 return 0;
248 u = strtoul(salt, &end, 10);
249 if (*end != '$')
250 return 0;
251 salt = end+1;
252 if (u < ROUNDS_MIN)
253 r = ROUNDS_MIN;
254 else if (u > ROUNDS_MAX)
255 return 0;
256 else
257 r = u;
258 /* needed when rounds is zero prefixed or out of bounds */
259 sprintf(rounds, "rounds=%u$", r);
260 }
261
262 for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++)
263 /* reject characters that interfere with /etc/shadow parsing */
264 if (salt[i] == '\n' || salt[i] == ':')
265 return 0;
266 slen = i;
267
268 /* B = sha(key salt key) */
269 sha512_init(&ctx);
270 sha512_update(&ctx, key, klen);
271 sha512_update(&ctx, salt, slen);
272 sha512_update(&ctx, key, klen);
273 sha512_sum(&ctx, md);
274
275 /* A = sha(key salt repeat-B alternate-B-key) */
276 sha512_init(&ctx);
277 sha512_update(&ctx, key, klen);
278 sha512_update(&ctx, salt, slen);
279 hashmd(&ctx, klen, md);
280 for (i = klen; i > 0; i >>= 1)
281 if (i & 1)
282 sha512_update(&ctx, md, sizeof md);
283 else
284 sha512_update(&ctx, key, klen);
285 sha512_sum(&ctx, md);
286
287 /* DP = sha(repeat-key), this step takes O(klen^2) time */
288 sha512_init(&ctx);
289 for (i = 0; i < klen; i++)
290 sha512_update(&ctx, key, klen);
291 sha512_sum(&ctx, kmd);
292
293 /* DS = sha(repeat-salt) */
294 sha512_init(&ctx);
295 for (i = 0; i < 16 + md[0]; i++)
296 sha512_update(&ctx, salt, slen);
297 sha512_sum(&ctx, smd);
298
299 /* iterate A = f(A,DP,DS), this step takes O(rounds*klen) time */
300 for (i = 0; i < r; i++) {
301 sha512_init(&ctx);
302 if (i % 2)
303 hashmd(&ctx, klen, kmd);
304 else
305 sha512_update(&ctx, md, sizeof md);
306 if (i % 3)
307 sha512_update(&ctx, smd, slen);
308 if (i % 7)
309 hashmd(&ctx, klen, kmd);
310 if (i % 2)
311 sha512_update(&ctx, md, sizeof md);
312 else
313 hashmd(&ctx, klen, kmd);
314 sha512_sum(&ctx, md);
315 }
316
317 /* output is $6$rounds=n$salt$hash */
318 p = output;
319 p += sprintf(p, "$6$%s%.*s$", rounds, slen, salt);
320 #if 1
321 static const unsigned char perm[][3] = {
322 0,21,42,22,43,1,44,2,23,3,24,45,25,46,4,
323 47,5,26,6,27,48,28,49,7,50,8,29,9,30,51,
324 31,52,10,53,11,32,12,33,54,34,55,13,56,14,35,
325 15,36,57,37,58,16,59,17,38,18,39,60,40,61,19,
326 62,20,41 };
327 for (i=0; i<21; i++) p = to64(p,
328 (md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
329 #else
330 p = to64(p, (md[0]<<16)|(md[21]<<8)|md[42], 4);
331 p = to64(p, (md[22]<<16)|(md[43]<<8)|md[1], 4);
332 p = to64(p, (md[44]<<16)|(md[2]<<8)|md[23], 4);
333 p = to64(p, (md[3]<<16)|(md[24]<<8)|md[45], 4);
334 p = to64(p, (md[25]<<16)|(md[46]<<8)|md[4], 4);
335 p = to64(p, (md[47]<<16)|(md[5]<<8)|md[26], 4);
336 p = to64(p, (md[6]<<16)|(md[27]<<8)|md[48], 4);
337 p = to64(p, (md[28]<<16)|(md[49]<<8)|md[7], 4);
338 p = to64(p, (md[50]<<16)|(md[8]<<8)|md[29], 4);
339 p = to64(p, (md[9]<<16)|(md[30]<<8)|md[51], 4);
340 p = to64(p, (md[31]<<16)|(md[52]<<8)|md[10], 4);
341 p = to64(p, (md[53]<<16)|(md[11]<<8)|md[32], 4);
342 p = to64(p, (md[12]<<16)|(md[33]<<8)|md[54], 4);
343 p = to64(p, (md[34]<<16)|(md[55]<<8)|md[13], 4);
344 p = to64(p, (md[56]<<16)|(md[14]<<8)|md[35], 4);
345 p = to64(p, (md[15]<<16)|(md[36]<<8)|md[57], 4);
346 p = to64(p, (md[37]<<16)|(md[58]<<8)|md[16], 4);
347 p = to64(p, (md[59]<<16)|(md[17]<<8)|md[38], 4);
348 p = to64(p, (md[18]<<16)|(md[39]<<8)|md[60], 4);
349 p = to64(p, (md[40]<<16)|(md[61]<<8)|md[19], 4);
350 p = to64(p, (md[62]<<16)|(md[20]<<8)|md[41], 4);
351 #endif
352 p = to64(p, md[63], 2);
353 *p = 0;
354 return output;
355 }
356
357 char *__crypt_sha512(const char *key, const char *setting, char *output)
358 {
359 static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
360 static const char testsetting[] = "$6$rounds=1234$abc0123456789$";
361 static const char testhash[] = "$6$rounds=1234$abc0123456789$BCpt8zLrc/RcyuXmCDOE1ALqMXB2MH6n1g891HhFj8.w7LxGv.FTkqq6Vxc/km3Y0jE0j24jY5PIv/oOu6reg1";
362 char testbuf[128];
363 char *p, *q;
364
365 p = sha512crypt(key, setting, output);
366 /* self test and stack cleanup */
367 q = sha512crypt(testkey, testsetting, testbuf);
368 if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
369 return "*";
370 return p;
371 }
372