lib/md5.c

   1 /*
   2  *      BIRD Library -- MD5 Hash Function and HMAC-MD5 Function
   3  *
   4  *      (c) 2015 CZ.NIC z.s.p.o.
   5  *
   6  *      The code was written by Colin Plumb in 1993, no copyright is claimed.
   7  *
   8  *      Adapted for BIRD by Martin Mares <mj@ucw.cz>
   9  *
  10  *      Can be freely distributed and used under the terms of the GNU GPL.
  11  */
  12
  13 #include "lib/md5.h"
  14
  15 #ifdef CPU_LITTLE_ENDIAN
  16 #define byteReverse(buf, len)   /* Nothing */
  17 #else
  18 void byteReverse(byte *buf, uint longs);
  19
  20 /*
  21  * Note: this code is harmless on little-endian machines.
  22  */
  23 void byteReverse(byte *buf, uint longs)
  24 {
  25   u32 t;
  26   do {
  27     t = (u32) ((uint) buf[3] << 8 | buf[2]) << 16 |
  28         ((uint) buf[1] << 8 | buf[0]);
  29     *(u32 *) buf = t;
  30     buf += 4;
  31   } while (--longs);
  32 }
  33 #endif
  34
  35 static void md5_transform(u32 buf[4], u32 const in[16]);
  36
  37 /*
  38  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  39  * initialization constants.
  40  */
  41 void
  42 md5_init(struct hash_context *CTX)
  43 {
  44   struct md5_context *ctx = (void *) CTX;
  45
  46   ctx->buf[0] = 0x67452301;
  47   ctx->buf[1] = 0xefcdab89;
  48   ctx->buf[2] = 0x98badcfe;
  49   ctx->buf[3] = 0x10325476;
  50
  51   ctx->bits[0] = 0;
  52   ctx->bits[1] = 0;
  53 }
  54
  55 /*
  56  * Update context to reflect the concatenation of another buffer full
  57  * of bytes.
  58  */
  59 void
  60 md5_update(struct hash_context *CTX, const byte *buf, uint len)
  61 {
  62   struct md5_context *ctx = (void *) CTX;
  63   u32 t;
  64
  65   /* Update bitcount */
  66
  67   t = ctx->bits[0];
  68   if ((ctx->bits[0] = t + ((u32) len << 3)) < t)
  69     ctx->bits[1]++;             /* Carry from low to high */
  70   ctx->bits[1] += len >> 29;
  71
  72   t = (t >> 3) & 0x3f;  /* Bytes already in shsInfo->data */
  73
  74   /* Handle any leading odd-sized chunks */
  75   if (t)
  76   {
  77     byte *p = (byte *) ctx->in + t;
  78
  79     t = 64 - t;
  80     if (len < t)
  81     {
  82       memcpy(p, buf, len);
  83       return;
  84     }
  85     memcpy(p, buf, t);
  86     byteReverse(ctx->in, 16);
  87     md5_transform(ctx->buf, (u32 *) ctx->in);
  88     buf += t;
  89     len -= t;
  90   }
  91
  92   /* Process data in 64-byte chunks */
  93   while (len >= 64)
  94   {
  95     memcpy(ctx->in, buf, 64);
  96     byteReverse(ctx->in, 16);
  97     md5_transform(ctx->buf, (u32 *) ctx->in);
  98     buf += 64;
  99     len -= 64;
 100   }
 101
 102   /* Handle any remaining bytes of data. */
 103   memcpy(ctx->in, buf, len);
 104 }
 105
 106 /*
 107  * Final wrapup - pad to 64-byte boundary with the bit pattern
 108  * 1 0* (64-bit count of bits processed, MSB-first)
 109  */
 110 byte *
 111 md5_final(struct hash_context *CTX)
 112 {
 113   struct md5_context *ctx = (void *) CTX;
 114   uint count;
 115   byte *p;
 116
 117   /* Compute number of bytes mod 64 */
 118   count = (ctx->bits[0] >> 3) & 0x3F;
 119
 120   /* Set the first char of padding to 0x80.  This is safe since there is
 121        always at least one byte free */
 122   p = ctx->in + count;
 123   *p++ = 0x80;
 124
 125   /* Bytes of padding needed to make 64 bytes */
 126   count = 64 - 1 - count;
 127
 128   /* Pad out to 56 mod 64 */
 129   if (count < 8)
 130   {
 131     /* Two lots of padding:  Pad the first block to 64 bytes */
 132     memset(p, 0, count);
 133     byteReverse(ctx->in, 16);
 134     md5_transform(ctx->buf, (u32 *) ctx->in);
 135
 136     /* Now fill the next block with 56 bytes */
 137     memset(ctx->in, 0, 56);
 138   }
 139   else
 140   {
 141     /* Pad block to 56 bytes */
 142     memset(p, 0, count - 8);
 143   }
 144   byteReverse(ctx->in, 14);
 145
 146   /* Append length in bits and transform */
 147   ((u32 *) ctx->in)[14] = ctx->bits[0];
 148   ((u32 *) ctx->in)[15] = ctx->bits[1];
 149
 150   md5_transform(ctx->buf, (u32 *) ctx->in);
 151   byteReverse((byte *) ctx->buf, 4);
 152
 153   return (byte*) ctx->buf;
 154 }
 155
 156 /* The four core functions - F1 is optimized somewhat */
 157
 158 /* #define F1(x, y, z) (x & y | ~x & z) */
 159 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 160 #define F2(x, y, z) F1(z, x, y)
 161 #define F3(x, y, z) (x ^ y ^ z)
 162 #define F4(x, y, z) (y ^ (x | ~z))
 163
 164 /* This is the central step in the MD5 algorithm. */
 165 #define MD5STEP(f, w, x, y, z, data, s) \
 166     ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 167
 168 /*
 169  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 170  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 171  * the data and converts bytes into longwords for this routine.
 172  */
 173 void
 174 md5_transform(u32 buf[4], u32 const in[16])
 175 {
 176   register u32 a, b, c, d;
 177
 178   a = buf[0];
 179   b = buf[1];
 180   c = buf[2];
 181   d = buf[3];
 182
 183   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 184   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 185   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 186   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 187   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 188   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 189   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 190   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 191   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 192   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 193   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 194   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 195   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 196   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 197   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 198   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 199
 200   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 201   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 202   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 203   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 204   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 205   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 206   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 207   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 208   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 209   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 210   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 211   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 212   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 213   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 214   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 215   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 216
 217   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 218   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 219   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 220   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 221   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 222   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 223   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 224   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 225   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 226   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 227   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 228   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 229   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 230   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 231   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 232   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 233
 234   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 235   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 236   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 237   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 238   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 239   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 240   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 241   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 242   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 243   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 244   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 245   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 246   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 247   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 248   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 249   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 250
 251   buf[0] += a;
 252   buf[1] += b;
 253   buf[2] += c;
 254   buf[3] += d;
 255 }