nasmlib/md5c.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 "md5.h"
  19
  20 #ifdef WORDS_LITTLEENDIAN
  21 #define byteReverse(buf, len)   /* Nothing */
  22 #else
  23 static void byteReverse(unsigned char *buf, unsigned longs);
  24
  25 /*
  26  * Note: this code is harmless on little-endian machines.
  27  */
  28 static void byteReverse(unsigned char *buf, unsigned longs)
  29 {
  30     uint32_t t;
  31     do {
  32         t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  33             ((unsigned) buf[1] << 8 | buf[0]);
  34         *(uint32_t *) buf = t;
  35         buf += 4;
  36     } while (--longs);
  37 }
  38 #endif
  39
  40 /*
  41  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  42  * initialization constants.
  43  */
  44 void MD5Init(MD5_CTX *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 MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len)
  60 {
  61     uint32_t t;
  62
  63     /* Update bitcount */
  64
  65     t = ctx->bits[0];
  66     if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  67         ctx->bits[1]++;         /* Carry from low to high */
  68     ctx->bits[1] += len >> 29;
  69
  70     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
  71
  72     /* Handle any leading odd-sized chunks */
  73
  74     if (t) {
  75         unsigned char *p = (unsigned char *) ctx->in + t;
  76
  77         t = 64 - t;
  78         if (len < t) {
  79             memcpy(p, buf, len);
  80             return;
  81         }
  82         memcpy(p, buf, t);
  83         byteReverse(ctx->in, 16);
  84         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  85         buf += t;
  86         len -= t;
  87     }
  88     /* Process data in 64-byte chunks */
  89
  90     while (len >= 64) {
  91         memcpy(ctx->in, buf, 64);
  92         byteReverse(ctx->in, 16);
  93         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  94         buf += 64;
  95         len -= 64;
  96     }
  97
  98     /* Handle any remaining bytes of data. */
  99
 100     memcpy(ctx->in, buf, len);
 101 }
 102
 103 /*
 104  * Final wrapup - pad to 64-byte boundary with the bit pattern
 105  * 1 0* (64-bit count of bits processed, MSB-first)
 106  */
 107 void MD5Final(unsigned char digest[16], MD5_CTX *ctx)
 108 {
 109     unsigned count;
 110     unsigned char *p;
 111
 112     /* Compute number of bytes mod 64 */
 113     count = (ctx->bits[0] >> 3) & 0x3F;
 114
 115     /* Set the first char of padding to 0x80.  This is safe since there is
 116        always at least one byte free */
 117     p = ctx->in + count;
 118     *p++ = 0x80;
 119
 120     /* Bytes of padding needed to make 64 bytes */
 121     count = 64 - 1 - count;
 122
 123     /* Pad out to 56 mod 64 */
 124     if (count < 8) {
 125         /* Two lots of padding:  Pad the first block to 64 bytes */
 126         memset(p, 0, count);
 127         byteReverse(ctx->in, 16);
 128         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 129
 130         /* Now fill the next block with 56 bytes */
 131         memset(ctx->in, 0, 56);
 132     } else {
 133         /* Pad block to 56 bytes */
 134         memset(p, 0, count - 8);
 135     }
 136     byteReverse(ctx->in, 14);
 137
 138     /* Append length in bits and transform */
 139     ((uint32_t *) ctx->in)[14] = ctx->bits[0];
 140     ((uint32_t *) ctx->in)[15] = ctx->bits[1];
 141
 142     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 143     byteReverse((unsigned char *) ctx->buf, 4);
 144     memcpy(digest, ctx->buf, 16);
 145     memset((char *) ctx, 0, sizeof(*ctx));      /* In case it's sensitive */
 146 }
 147
 148 /* The four core functions - F1 is optimized somewhat */
 149
 150 /* #define F1(x, y, z) (x & y | ~x & z) */
 151 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 152 #define F2(x, y, z) F1(z, x, y)
 153 #define F3(x, y, z) (x ^ y ^ z)
 154 #define F4(x, y, z) (y ^ (x | ~z))
 155
 156 /* This is the central step in the MD5 algorithm. */
 157 #define MD5STEP(f, w, x, y, z, data, s) \
 158         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 159
 160 /*
 161  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 162  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 163  * the data and converts bytes into longwords for this routine.
 164  */
 165 void MD5Transform(uint32_t buf[4], uint32_t const in[16])
 166 {
 167     register uint32_t a, b, c, d;
 168
 169     a = buf[0];
 170     b = buf[1];
 171     c = buf[2];
 172     d = buf[3];
 173
 174     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 175     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 176     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 177     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 178     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 179     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 180     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 181     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 182     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 183     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 184     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 185     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 186     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 187     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 188     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 189     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 190
 191     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 192     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 193     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 194     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 195     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 196     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 197     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 198     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 199     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 200     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 201     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 202     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 203     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 204     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 205     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 206     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 207
 208     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 209     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 210     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 211     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 212     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 213     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 214     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 215     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 216     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 217     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 218     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 219     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 220     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 221     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 222     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 223     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 224
 225     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 226     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 227     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 228     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 229     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 230     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 231     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 232     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 233     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 234     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 235     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 236     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 237     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 238     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 239     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 240     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 241
 242     buf[0] += a;
 243     buf[1] += b;
 244     buf[2] += c;
 245     buf[3] += d;
 246 }