lib/md5.c

   1 /*
   2  * MD5 hashing code copied from Lepton's crack <http://usuarios.lycos.es/reinob/>
   3  *
   4  * Adapted to be API-compatible with the previous (GPL-incompatible) code.
   5  */
   6
   7 /*
   8  * This code implements the MD5 message-digest algorithm.
   9  * The algorithm is due to Ron Rivest.  This code was
  10  * written by Colin Plumb in 1993, no copyright is claimed.
  11  * This code is in the public domain; do with it what you wish.
  12  *
  13  * Equivalent code is available from RSA Data Security, Inc.
  14  * This code has been tested against that, and is equivalent,
  15  * except that you don't need to include two pages of legalese
  16  * with every copy.
  17  *
  18  * To compute the message digest of a chunk of bytes, declare an
  19  * MD5Context structure, pass it to MD5Init, call MD5Update as
  20  * needed on buffers full of bytes, and then call MD5Final, which
  21  * will fill a supplied 16-byte array with the digest.
  22  */
  23
  24 #include <sys/types.h>
  25 #include <string.h>             /* for memcpy() */
  26 #include <stdio.h>
  27 #include "md5.h"
  28
  29 static void md5_transform(uint32_t buf[4], uint32_t const in[16]);
  30
  31 /*
  32  * Wrapper function for all-in-one MD5
  33  *
  34  * Bernardo Reino, aka Lepton.
  35  * 20021120
  36  */
  37
  38 /* Turns out MD5 was designed for little-endian machines. If we're running
  39    on a big-endian machines, we have to swap some bytes. Since detecting
  40    endianness at compile time reliably seems pretty hard, let's do it at
  41    run-time. It's not like we're going to checksum megabytes of data... */
  42 static uint32_t cvt32(uint32_t val)
  43 {
  44         static int little_endian = -1;
  45
  46         if (little_endian == -1)
  47         {
  48                 little_endian = 1;
  49                 little_endian = *((char*) &little_endian);
  50         }
  51
  52         if (little_endian)
  53                 return val;
  54         else
  55                 return (val >> 24) |
  56                        ((val >> 8) & 0xff00) |
  57                        ((val << 8) & 0xff0000) |
  58                        (val << 24);
  59 }
  60
  61 void md5_init(struct MD5Context *ctx)
  62 {
  63         ctx->buf[0] = 0x67452301;
  64         ctx->buf[1] = 0xefcdab89;
  65         ctx->buf[2] = 0x98badcfe;
  66         ctx->buf[3] = 0x10325476;
  67
  68         ctx->bits[0] = 0;
  69         ctx->bits[1] = 0;
  70 }
  71
  72 /*
  73  * Update context to reflect the concatenation of another buffer full
  74  * of bytes.
  75  */
  76 void md5_append(struct MD5Context *ctx, const md5_byte_t *buf,
  77                 unsigned int len)
  78 {
  79         uint32_t t;
  80
  81         /* Update bitcount */
  82
  83         t = ctx->bits[0];
  84         if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  85                 ctx->bits[1]++; /* Carry from low to high */
  86         ctx->bits[1] += len >> 29;
  87
  88         t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
  89
  90         /* Handle any leading odd-sized chunks */
  91
  92         if (t) {
  93                 unsigned char *p = (unsigned char *) ctx->in + t;
  94
  95                 t = 64 - t;
  96                 if (len < t) {
  97                         memcpy(p, buf, len);
  98                         return;
  99                 }
 100                 memcpy(p, buf, t);
 101                 md5_transform(ctx->buf, (uint32_t *) ctx->in);
 102                 buf += t;
 103                 len -= t;
 104         }
 105         /* Process data in 64-byte chunks */
 106
 107         while (len >= 64) {
 108                 memcpy(ctx->in, buf, 64);
 109                 md5_transform(ctx->buf, (uint32_t *) ctx->in);
 110                 buf += 64;
 111                 len -= 64;
 112         }
 113
 114         /* Handle any remaining bytes of data. */
 115
 116         memcpy(ctx->in, buf, len);
 117 }
 118
 119 /*
 120  * Final wrapup - pad to 64-byte boundary with the bit pattern
 121  * 1 0* (64-bit count of bits processed, MSB-first)
 122  */
 123 void md5_finish(struct MD5Context *ctx, md5_byte_t digest[16])
 124 {
 125         unsigned count;
 126         unsigned char *p;
 127
 128         /* Compute number of bytes mod 64 */
 129         count = (ctx->bits[0] >> 3) & 0x3F;
 130
 131         /* Set the first char of padding to 0x80.  This is safe since there is
 132            always at least one byte free */
 133         p = ctx->in + count;
 134         *p++ = 0x80;
 135
 136         /* Bytes of padding needed to make 64 bytes */
 137         count = 64 - 1 - count;
 138
 139         /* Pad out to 56 mod 64 */
 140         if (count < 8) {
 141                 /* Two lots of padding:  Pad the first block to 64 bytes */
 142                 memset(p, 0, count);
 143                 md5_transform(ctx->buf, (uint32_t *) ctx->in);
 144
 145                 /* Now fill the next block with 56 bytes */
 146                 memset(ctx->in, 0, 56);
 147         } else {
 148                 /* Pad block to 56 bytes */
 149                 memset(p, 0, count - 8);
 150         }
 151
 152         /* Append length in bits and transform */
 153         ((uint32_t *) ctx->in)[14] = cvt32(ctx->bits[0]);
 154         ((uint32_t *) ctx->in)[15] = cvt32(ctx->bits[1]);
 155
 156         md5_transform(ctx->buf, (uint32_t *) ctx->in);
 157         ctx->buf[0] = cvt32(ctx->buf[0]);
 158         ctx->buf[1] = cvt32(ctx->buf[1]);
 159         ctx->buf[2] = cvt32(ctx->buf[2]);
 160         ctx->buf[3] = cvt32(ctx->buf[3]);
 161         memcpy(digest, ctx->buf, 16);
 162         memset(ctx, 0, sizeof(ctx));    /* In case it's sensitive */
 163 }
 164
 165 void md5_finish_ascii(struct MD5Context *context, char *ascii)
 166 {
 167         md5_byte_t bin[16];
 168         int i;
 169
 170         md5_finish(context, bin);
 171         for (i = 0; i < 16; i ++)
 172                 sprintf(ascii + i * 2, "%02x", bin[i]);
 173 }
 174
 175 /* The four core functions - F1 is optimized somewhat */
 176
 177 /* #define F1(x, y, z) (x & y | ~x & z) */
 178 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 179 #define F2(x, y, z) F1(z, x, y)
 180 #define F3(x, y, z) (x ^ y ^ z)
 181 #define F4(x, y, z) (y ^ (x | ~z))
 182
 183 /* This is the central step in the MD5 algorithm. */
 184 #define MD5STEP(f, w, x, y, z, data, s) \
 185         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 186
 187 /*
 188  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 189  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 190  * the data and converts bytes into longwords for this routine.
 191  */
 192 static void md5_transform(uint32_t buf[4], uint32_t const in[16])
 193 {
 194         register uint32_t a, b, c, d;
 195
 196         a = buf[0];
 197         b = buf[1];
 198         c = buf[2];
 199         d = buf[3];
 200
 201         MD5STEP(F1, a, b, c, d, cvt32(in[0]) + 0xd76aa478, 7);
 202         MD5STEP(F1, d, a, b, c, cvt32(in[1]) + 0xe8c7b756, 12);
 203         MD5STEP(F1, c, d, a, b, cvt32(in[2]) + 0x242070db, 17);
 204         MD5STEP(F1, b, c, d, a, cvt32(in[3]) + 0xc1bdceee, 22);
 205         MD5STEP(F1, a, b, c, d, cvt32(in[4]) + 0xf57c0faf, 7);
 206         MD5STEP(F1, d, a, b, c, cvt32(in[5]) + 0x4787c62a, 12);
 207         MD5STEP(F1, c, d, a, b, cvt32(in[6]) + 0xa8304613, 17);
 208         MD5STEP(F1, b, c, d, a, cvt32(in[7]) + 0xfd469501, 22);
 209         MD5STEP(F1, a, b, c, d, cvt32(in[8]) + 0x698098d8, 7);
 210         MD5STEP(F1, d, a, b, c, cvt32(in[9]) + 0x8b44f7af, 12);
 211         MD5STEP(F1, c, d, a, b, cvt32(in[10]) + 0xffff5bb1, 17);
 212         MD5STEP(F1, b, c, d, a, cvt32(in[11]) + 0x895cd7be, 22);
 213         MD5STEP(F1, a, b, c, d, cvt32(in[12]) + 0x6b901122, 7);
 214         MD5STEP(F1, d, a, b, c, cvt32(in[13]) + 0xfd987193, 12);
 215         MD5STEP(F1, c, d, a, b, cvt32(in[14]) + 0xa679438e, 17);
 216         MD5STEP(F1, b, c, d, a, cvt32(in[15]) + 0x49b40821, 22);
 217
 218         MD5STEP(F2, a, b, c, d, cvt32(in[1]) + 0xf61e2562, 5);
 219         MD5STEP(F2, d, a, b, c, cvt32(in[6]) + 0xc040b340, 9);
 220         MD5STEP(F2, c, d, a, b, cvt32(in[11]) + 0x265e5a51, 14);
 221         MD5STEP(F2, b, c, d, a, cvt32(in[0]) + 0xe9b6c7aa, 20);
 222         MD5STEP(F2, a, b, c, d, cvt32(in[5]) + 0xd62f105d, 5);
 223         MD5STEP(F2, d, a, b, c, cvt32(in[10]) + 0x02441453, 9);
 224         MD5STEP(F2, c, d, a, b, cvt32(in[15]) + 0xd8a1e681, 14);
 225         MD5STEP(F2, b, c, d, a, cvt32(in[4]) + 0xe7d3fbc8, 20);
 226         MD5STEP(F2, a, b, c, d, cvt32(in[9]) + 0x21e1cde6, 5);
 227         MD5STEP(F2, d, a, b, c, cvt32(in[14]) + 0xc33707d6, 9);
 228         MD5STEP(F2, c, d, a, b, cvt32(in[3]) + 0xf4d50d87, 14);
 229         MD5STEP(F2, b, c, d, a, cvt32(in[8]) + 0x455a14ed, 20);
 230         MD5STEP(F2, a, b, c, d, cvt32(in[13]) + 0xa9e3e905, 5);
 231         MD5STEP(F2, d, a, b, c, cvt32(in[2]) + 0xfcefa3f8, 9);
 232         MD5STEP(F2, c, d, a, b, cvt32(in[7]) + 0x676f02d9, 14);
 233         MD5STEP(F2, b, c, d, a, cvt32(in[12]) + 0x8d2a4c8a, 20);
 234
 235         MD5STEP(F3, a, b, c, d, cvt32(in[5]) + 0xfffa3942, 4);
 236         MD5STEP(F3, d, a, b, c, cvt32(in[8]) + 0x8771f681, 11);
 237         MD5STEP(F3, c, d, a, b, cvt32(in[11]) + 0x6d9d6122, 16);
 238         MD5STEP(F3, b, c, d, a, cvt32(in[14]) + 0xfde5380c, 23);
 239         MD5STEP(F3, a, b, c, d, cvt32(in[1]) + 0xa4beea44, 4);
 240         MD5STEP(F3, d, a, b, c, cvt32(in[4]) + 0x4bdecfa9, 11);
 241         MD5STEP(F3, c, d, a, b, cvt32(in[7]) + 0xf6bb4b60, 16);
 242         MD5STEP(F3, b, c, d, a, cvt32(in[10]) + 0xbebfbc70, 23);
 243         MD5STEP(F3, a, b, c, d, cvt32(in[13]) + 0x289b7ec6, 4);
 244         MD5STEP(F3, d, a, b, c, cvt32(in[0]) + 0xeaa127fa, 11);
 245         MD5STEP(F3, c, d, a, b, cvt32(in[3]) + 0xd4ef3085, 16);
 246         MD5STEP(F3, b, c, d, a, cvt32(in[6]) + 0x04881d05, 23);
 247         MD5STEP(F3, a, b, c, d, cvt32(in[9]) + 0xd9d4d039, 4);
 248         MD5STEP(F3, d, a, b, c, cvt32(in[12]) + 0xe6db99e5, 11);
 249         MD5STEP(F3, c, d, a, b, cvt32(in[15]) + 0x1fa27cf8, 16);
 250         MD5STEP(F3, b, c, d, a, cvt32(in[2]) + 0xc4ac5665, 23);
 251
 252         MD5STEP(F4, a, b, c, d, cvt32(in[0]) + 0xf4292244, 6);
 253         MD5STEP(F4, d, a, b, c, cvt32(in[7]) + 0x432aff97, 10);
 254         MD5STEP(F4, c, d, a, b, cvt32(in[14]) + 0xab9423a7, 15);
 255         MD5STEP(F4, b, c, d, a, cvt32(in[5]) + 0xfc93a039, 21);
 256         MD5STEP(F4, a, b, c, d, cvt32(in[12]) + 0x655b59c3, 6);
 257         MD5STEP(F4, d, a, b, c, cvt32(in[3]) + 0x8f0ccc92, 10);
 258         MD5STEP(F4, c, d, a, b, cvt32(in[10]) + 0xffeff47d, 15);
 259         MD5STEP(F4, b, c, d, a, cvt32(in[1]) + 0x85845dd1, 21);
 260         MD5STEP(F4, a, b, c, d, cvt32(in[8]) + 0x6fa87e4f, 6);
 261         MD5STEP(F4, d, a, b, c, cvt32(in[15]) + 0xfe2ce6e0, 10);
 262         MD5STEP(F4, c, d, a, b, cvt32(in[6]) + 0xa3014314, 15);
 263         MD5STEP(F4, b, c, d, a, cvt32(in[13]) + 0x4e0811a1, 21);
 264         MD5STEP(F4, a, b, c, d, cvt32(in[4]) + 0xf7537e82, 6);
 265         MD5STEP(F4, d, a, b, c, cvt32(in[11]) + 0xbd3af235, 10);
 266         MD5STEP(F4, c, d, a, b, cvt32(in[2]) + 0x2ad7d2bb, 15);
 267         MD5STEP(F4, b, c, d, a, cvt32(in[9]) + 0xeb86d391, 21);
 268
 269         buf[0] += a;
 270         buf[1] += b;
 271         buf[2] += c;
 272         buf[3] += d;
 273 }