src/crypt/crypt_md5.c

   1 /*
   2  * md5 crypt implementation
   3  *
   4  * original md5 crypt design is from Poul-Henning Kamp
   5  * this implementation was created based on the code in freebsd
   6  * at least 32bit int is assumed, key is limited and $1$ prefix is mandatory,
   7  * on error "*" is returned
   8  */
   9 #include <string.h>
  10 #include <stdint.h>
  11
  12 /* public domain md5 implementation based on rfc1321 and libtomcrypt */
  13
  14 struct md5 {
  15         uint64_t len;    /* processed message length */
  16         uint32_t h[4];   /* hash state */
  17         uint8_t buf[64]; /* message block buffer */
  18 };
  19
  20 static uint32_t rol(uint32_t n, int k) { return (n << k) | (n >> (32-k)); }
  21 #define F(x,y,z) (z ^ (x & (y ^ z)))
  22 #define G(x,y,z) (y ^ (z & (y ^ x)))
  23 #define H(x,y,z) (x ^ y ^ z)
  24 #define I(x,y,z) (y ^ (x | ~z))
  25 #define FF(a,b,c,d,w,s,t) a += F(b,c,d) + w + t; a = rol(a,s) + b
  26 #define GG(a,b,c,d,w,s,t) a += G(b,c,d) + w + t; a = rol(a,s) + b
  27 #define HH(a,b,c,d,w,s,t) a += H(b,c,d) + w + t; a = rol(a,s) + b
  28 #define II(a,b,c,d,w,s,t) a += I(b,c,d) + w + t; a = rol(a,s) + b
  29
  30 static const uint32_t tab[64] = {
  31 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
  32 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
  33 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
  34 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
  35 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
  36 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
  37 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
  38 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
  39 };
  40
  41 static void processblock(struct md5 *s, const uint8_t *buf)
  42 {
  43         uint32_t i, W[16], a, b, c, d;
  44
  45         for (i = 0; i < 16; i++) {
  46                 W[i] = buf[4*i];
  47                 W[i] |= (uint32_t)buf[4*i+1]<<8;
  48                 W[i] |= (uint32_t)buf[4*i+2]<<16;
  49                 W[i] |= (uint32_t)buf[4*i+3]<<24;
  50         }
  51
  52         a = s->h[0];
  53         b = s->h[1];
  54         c = s->h[2];
  55         d = s->h[3];
  56
  57         i = 0;
  58         while (i < 16) {
  59                 FF(a,b,c,d, W[i],  7, tab[i]); i++;
  60                 FF(d,a,b,c, W[i], 12, tab[i]); i++;
  61                 FF(c,d,a,b, W[i], 17, tab[i]); i++;
  62                 FF(b,c,d,a, W[i], 22, tab[i]); i++;
  63         }
  64         while (i < 32) {
  65                 GG(a,b,c,d, W[(5*i+1)%16],  5, tab[i]); i++;
  66                 GG(d,a,b,c, W[(5*i+1)%16],  9, tab[i]); i++;
  67                 GG(c,d,a,b, W[(5*i+1)%16], 14, tab[i]); i++;
  68                 GG(b,c,d,a, W[(5*i+1)%16], 20, tab[i]); i++;
  69         }
  70         while (i < 48) {
  71                 HH(a,b,c,d, W[(3*i+5)%16],  4, tab[i]); i++;
  72                 HH(d,a,b,c, W[(3*i+5)%16], 11, tab[i]); i++;
  73                 HH(c,d,a,b, W[(3*i+5)%16], 16, tab[i]); i++;
  74                 HH(b,c,d,a, W[(3*i+5)%16], 23, tab[i]); i++;
  75         }
  76         while (i < 64) {
  77                 II(a,b,c,d, W[7*i%16],  6, tab[i]); i++;
  78                 II(d,a,b,c, W[7*i%16], 10, tab[i]); i++;
  79                 II(c,d,a,b, W[7*i%16], 15, tab[i]); i++;
  80                 II(b,c,d,a, W[7*i%16], 21, tab[i]); i++;
  81         }
  82
  83         s->h[0] += a;
  84         s->h[1] += b;
  85         s->h[2] += c;
  86         s->h[3] += d;
  87 }
  88
  89 static void pad(struct md5 *s)
  90 {
  91         unsigned r = s->len % 64;
  92
  93         s->buf[r++] = 0x80;
  94         if (r > 56) {
  95                 memset(s->buf + r, 0, 64 - r);
  96                 r = 0;
  97                 processblock(s, s->buf);
  98         }
  99         memset(s->buf + r, 0, 56 - r);
 100         s->len *= 8;
 101         s->buf[56] = s->len;
 102         s->buf[57] = s->len >> 8;
 103         s->buf[58] = s->len >> 16;
 104         s->buf[59] = s->len >> 24;
 105         s->buf[60] = s->len >> 32;
 106         s->buf[61] = s->len >> 40;
 107         s->buf[62] = s->len >> 48;
 108         s->buf[63] = s->len >> 56;
 109         processblock(s, s->buf);
 110 }
 111
 112 static void md5_init(struct md5 *s)
 113 {
 114         s->len = 0;
 115         s->h[0] = 0x67452301;
 116         s->h[1] = 0xefcdab89;
 117         s->h[2] = 0x98badcfe;
 118         s->h[3] = 0x10325476;
 119 }
 120
 121 static void md5_sum(struct md5 *s, uint8_t *md)
 122 {
 123         int i;
 124
 125         pad(s);
 126         for (i = 0; i < 4; i++) {
 127                 md[4*i] = s->h[i];
 128                 md[4*i+1] = s->h[i] >> 8;
 129                 md[4*i+2] = s->h[i] >> 16;
 130                 md[4*i+3] = s->h[i] >> 24;
 131         }
 132 }
 133
 134 static void md5_update(struct md5 *s, const void *m, unsigned long len)
 135 {
 136         const uint8_t *p = m;
 137         unsigned r = s->len % 64;
 138
 139         s->len += len;
 140         if (r) {
 141                 if (len < 64 - r) {
 142                         memcpy(s->buf + r, p, len);
 143                         return;
 144                 }
 145                 memcpy(s->buf + r, p, 64 - r);
 146                 len -= 64 - r;
 147                 p += 64 - r;
 148                 processblock(s, s->buf);
 149         }
 150         for (; len >= 64; len -= 64, p += 64)
 151                 processblock(s, p);
 152         memcpy(s->buf, p, len);
 153 }
 154
 155 /*-
 156  * Copyright (c) 2003 Poul-Henning Kamp
 157  * All rights reserved.
 158  *
 159  * Redistribution and use in source and binary forms, with or without
 160  * modification, are permitted provided that the following conditions
 161  * are met:
 162  * 1. Redistributions of source code must retain the above copyright
 163  *    notice, this list of conditions and the following disclaimer.
 164  * 2. Redistributions in binary form must reproduce the above copyright
 165  *    notice, this list of conditions and the following disclaimer in the
 166  *    documentation and/or other materials provided with the distribution.
 167  *
 168  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 169  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 170  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 171  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 172  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 173  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 174  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 175  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 176  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 177  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 178  * SUCH DAMAGE.
 179  */
 180
 181 /* key limit is not part of the original design, added for DoS protection */
 182 #define KEY_MAX 30000
 183 #define SALT_MAX 8
 184
 185 static const unsigned char b64[] =
 186 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 187
 188 static char *to64(char *s, unsigned int u, int n)
 189 {
 190         while (--n >= 0) {
 191                 *s++ = b64[u % 64];
 192                 u /= 64;
 193         }
 194         return s;
 195 }
 196
 197 static char *md5crypt(const char *key, const char *setting, char *output)
 198 {
 199         struct md5 ctx;
 200         unsigned char md[16];
 201         unsigned int i, klen, slen;
 202         const char *salt;
 203         char *p;
 204
 205         /* reject large keys */
 206         klen = strnlen(key, KEY_MAX+1);
 207         if (klen > KEY_MAX)
 208                 return 0;
 209
 210         /* setting: $1$salt$ (closing $ is optional) */
 211         if (strncmp(setting, "$1$", 3) != 0)
 212                 return 0;
 213         salt = setting + 3;
 214         for (i = 0; i < SALT_MAX && salt[i] && salt[i] != '$'; i++);
 215         slen = i;
 216
 217         /* md5(key salt key) */
 218         md5_init(&ctx);
 219         md5_update(&ctx, key, klen);
 220         md5_update(&ctx, salt, slen);
 221         md5_update(&ctx, key, klen);
 222         md5_sum(&ctx, md);
 223
 224         /* md5(key $1$ salt repeated-md weird-key[0]-0) */
 225         md5_init(&ctx);
 226         md5_update(&ctx, key, klen);
 227         md5_update(&ctx, setting, 3 + slen);
 228         for (i = klen; i > sizeof md; i -= sizeof md)
 229                 md5_update(&ctx, md, sizeof md);
 230         md5_update(&ctx, md, i);
 231         md[0] = 0;
 232         for (i = klen; i; i >>= 1)
 233                 if (i & 1)
 234                         md5_update(&ctx, md, 1);
 235                 else
 236                         md5_update(&ctx, key, 1);
 237         md5_sum(&ctx, md);
 238
 239         /* md = f(md, key, salt) iteration */
 240         for (i = 0; i < 1000; i++) {
 241                 md5_init(&ctx);
 242                 if (i % 2)
 243                         md5_update(&ctx, key, klen);
 244                 else
 245                         md5_update(&ctx, md, sizeof md);
 246                 if (i % 3)
 247                         md5_update(&ctx, salt, slen);
 248                 if (i % 7)
 249                         md5_update(&ctx, key, klen);
 250                 if (i % 2)
 251                         md5_update(&ctx, md, sizeof md);
 252                 else
 253                         md5_update(&ctx, key, klen);
 254                 md5_sum(&ctx, md);
 255         }
 256
 257         /* output is $1$salt$hash */
 258         memcpy(output, setting, 3 + slen);
 259         p = output + 3 + slen;
 260         *p++ = '$';
 261         static const unsigned char perm[][3] = {
 262                 0,6,12,1,7,13,2,8,14,3,9,15,4,10,5 };
 263         for (i=0; i<5; i++) p = to64(p,
 264                 (md[perm[i][0]]<<16)|(md[perm[i][1]]<<8)|md[perm[i][2]], 4);
 265         p = to64(p, md[11], 2);
 266         *p = 0;
 267
 268         return output;
 269 }
 270
 271 char *__crypt_md5(const char *key, const char *setting, char *output)
 272 {
 273         static const char testkey[] = "Xy01@#\x01\x02\x80\x7f\xff\r\n\x81\t !";
 274         static const char testsetting[] = "$1$abcd0123$";
 275         static const char testhash[] = "$1$abcd0123$9Qcg8DyviekV3tDGMZynJ1";
 276         char testbuf[64];
 277         char *p, *q;
 278
 279         p = md5crypt(key, setting, output);
 280         /* self test and stack cleanup */
 281         q = md5crypt(testkey, testsetting, testbuf);
 282         if (!p || q != testbuf || memcmp(testbuf, testhash, sizeof testhash))
 283                 return "*";
 284         return p;
 285 }