src/lib/md5.c

   1 /*
   2  * This code implements the MD5 message-digest algorithm.
   3  * The algorithm is due to Ron Rivest.  This code was
   4  * written by Colin Plumb in 1993, no copyright is claimed.
   5  * This code is in the public domain; do with it what you wish.
   6  *
   7  * Equivalent code is available from RSA Data Security, Inc.
   8  * This code has been tested against that, and is equivalent,
   9  * except that you don't need to include two pages of legalese
  10  * with every copy.
  11  *
  12  * To compute the message digest of a chunk of bytes, declare an
  13  * MD5Context structure, pass it to MD5Init, call MD5Update as
  14  * needed on buffers full of bytes, and then call MD5Final, which
  15  * will fill a supplied 16-byte array with the digest.
  16  */
  17
  18 #include <string.h>
  19 #include "md5.h"
  20 #define uint32 uint32_t
  21
  22 #if 0 /* don't need 100% correct md5, just fast md5. */
  23 #ifdef sgi
  24 #define HIGHFIRST
  25 #endif
  26
  27 #ifdef sun
  28 #define HIGHFIRST
  29 #endif
  30 #endif /* skip this */
  31
  32 #ifndef HIGHFIRST
  33 #define byteReverse(buf, len)   /* Nothing */
  34 #else
  35 /*
  36  * Note: this code is harmless on little-endian machines.
  37  */
  38 void byteReverse(unsigned char *buf, unsigned longs)
  39 {
  40     uint32 t;
  41     do {
  42         t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  43             ((unsigned) buf[1] << 8 | buf[0]);
  44         *(uint32 *) buf = t;
  45         buf += 4;
  46     } while (--longs);
  47 }
  48 #endif
  49
  50 /*
  51  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  52  * initialization constants.
  53  */
  54 void MD5Init(struct MD5Context *ctx)
  55 {
  56     ctx->buf[0] = 0x67452301;
  57     ctx->buf[1] = 0xefcdab89;
  58     ctx->buf[2] = 0x98badcfe;
  59     ctx->buf[3] = 0x10325476;
  60
  61     ctx->bits[0] = 0;
  62     ctx->bits[1] = 0;
  63 }
  64
  65 /*
  66  * Update context to reflect the concatenation of another buffer full
  67  * of bytes.
  68  */
  69 void MD5Update(struct MD5Context *ctx, const unsigned char *buf, unsigned len)
  70 {
  71     uint32 t;
  72
  73     /* Update bitcount */
  74
  75     t = ctx->bits[0];
  76     if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
  77         ctx->bits[1]++;         /* Carry from low to high */
  78     ctx->bits[1] += len >> 29;
  79
  80     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
  81
  82     /* Handle any leading odd-sized chunks */
  83
  84     if (t) {
  85         unsigned char *p = (unsigned char *) ctx->in + t;
  86
  87         t = 64 - t;
  88         if (len < t) {
  89             memcpy(p, buf, len);
  90             return;
  91         }
  92         memcpy(p, buf, t);
  93         byteReverse(ctx->in, 16);
  94         MD5Transform(ctx->buf, (uint32 *) ctx->in);
  95         buf += t;
  96         len -= t;
  97     }
  98     /* Process data in 64-byte chunks */
  99
 100     while (len >= 64) {
 101         memcpy(ctx->in, buf, 64);
 102         byteReverse(ctx->in, 16);
 103         MD5Transform(ctx->buf, (uint32 *) ctx->in);
 104         buf += 64;
 105         len -= 64;
 106     }
 107
 108     /* Handle any remaining bytes of data. */
 109
 110     memcpy(ctx->in, buf, len);
 111 }
 112
 113 /*
 114  * Final wrapup - pad to 64-byte boundary with the bit pattern
 115  * 1 0* (64-bit count of bits processed, MSB-first)
 116  */
 117 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
 118 {
 119     unsigned count;
 120     unsigned char *p;
 121
 122     /* Compute number of bytes mod 64 */
 123     count = (ctx->bits[0] >> 3) & 0x3F;
 124
 125     /* Set the first char of padding to 0x80.  This is safe since there is
 126        always at least one byte free */
 127     p = ctx->in + count;
 128     *p++ = 0x80;
 129
 130     /* Bytes of padding needed to make 64 bytes */
 131     count = 64 - 1 - count;
 132
 133     /* Pad out to 56 mod 64 */
 134     if (count < 8) {
 135         /* Two lots of padding:  Pad the first block to 64 bytes */
 136         memset(p, 0, count);
 137         byteReverse(ctx->in, 16);
 138         MD5Transform(ctx->buf, (uint32 *) ctx->in);
 139
 140         /* Now fill the next block with 56 bytes */
 141         memset(ctx->in, 0, 56);
 142     } else {
 143         /* Pad block to 56 bytes */
 144         memset(p, 0, count - 8);
 145     }
 146     byteReverse(ctx->in, 14);
 147
 148     /* Append length in bits and transform */
 149     ((uint32 *) ctx->in)[14] = ctx->bits[0];
 150     ((uint32 *) ctx->in)[15] = ctx->bits[1];
 151
 152     MD5Transform(ctx->buf, (uint32 *) ctx->in);
 153     byteReverse((unsigned char *) ctx->buf, 4);
 154     memcpy(digest, ctx->buf, 16);
 155     memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
 156 }
 157
 158
 159 /* The four core functions - F1 is optimized somewhat */
 160
 161 /* #define F1(x, y, z) (x & y | ~x & z) */
 162 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 163 #define F2(x, y, z) F1(z, x, y)
 164 #define F3(x, y, z) (x ^ y ^ z)
 165 #define F4(x, y, z) (y ^ (x | ~z))
 166
 167 /* This is the central step in the MD5 algorithm. */
 168 #define MD5STEP(f, w, x, y, z, data, s) \
 169         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 170
 171 /*
 172  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 173  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 174  * the data and converts bytes into longwords for this routine.
 175  */
 176 void MD5Transform(uint32 buf[4], uint32 in[16])
 177 {
 178     register uint32 a, b, c, d;
 179
 180     a = buf[0];
 181     b = buf[1];
 182     c = buf[2];
 183     d = buf[3];
 184
 185     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 186     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 187     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 188     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 189     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 190     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 191     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 192     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 193     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 194     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 195     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 196     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 197     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 198     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 199     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 200     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 201
 202     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 203     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 204     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 205     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 206     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 207     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 208     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 209     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 210     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 211     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 212     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 213     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 214     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 215     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 216     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 217     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 218
 219     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 220     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 221     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 222     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 223     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 224     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 225     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 226     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 227     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 228     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 229     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 230     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 231     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 232     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 233     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 234     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 235
 236     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 237     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 238     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 239     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 240     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 241     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 242     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 243     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 244     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 245     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 246     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 247     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 248     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 249     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 250     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 251     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 252
 253     buf[0] += a;
 254     buf[1] += b;
 255     buf[2] += c;
 256     buf[3] += d;
 257 }