md5_utils.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  * Changed so as no longer to depend on Colin Plumb's `usual.h' header
  18  * definitions
  19  *  - Ian Jackson <ian@chiark.greenend.org.uk>.
  20  * Still in the public domain.
  21  */
  22
  23 #include <sys/types.h>    /* for stupid systems */
  24
  25 #include <string.h>   /* for memcpy() */
  26
  27 #include "md5_utils.h"
  28
  29 void
  30 byteSwap(UWORD32 *buf, unsigned words)
  31 {
  32     md5byte *p;
  33
  34     /* Only swap bytes for big endian machines */
  35     int i = 1;
  36
  37     if (*(char *)&i == 1)
  38         return;
  39
  40     p = (md5byte *)buf;
  41
  42     do
  43     {
  44         *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
  45                  ((unsigned)p[1] << 8 | p[0]);
  46         p += 4;
  47     }
  48     while (--words);
  49 }
  50
  51 /*
  52  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  53  * initialization constants.
  54  */
  55 void
  56 MD5Init(struct MD5Context *ctx)
  57 {
  58     ctx->buf[0] = 0x67452301;
  59     ctx->buf[1] = 0xefcdab89;
  60     ctx->buf[2] = 0x98badcfe;
  61     ctx->buf[3] = 0x10325476;
  62
  63     ctx->bytes[0] = 0;
  64     ctx->bytes[1] = 0;
  65 }
  66
  67 /*
  68  * Update context to reflect the concatenation of another buffer full
  69  * of bytes.
  70  */
  71 void
  72 MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len)
  73 {
  74     UWORD32 t;
  75
  76     /* Update byte count */
  77
  78     t = ctx->bytes[0];
  79
  80     if ((ctx->bytes[0] = t + len) < t)
  81         ctx->bytes[1]++;  /* Carry from low to high */
  82
  83     t = 64 - (t & 0x3f);  /* Space available in ctx->in (at least 1) */
  84
  85     if (t > len)
  86     {
  87         memcpy((md5byte *)ctx->in + 64 - t, buf, len);
  88         return;
  89     }
  90
  91     /* First chunk is an odd size */
  92     memcpy((md5byte *)ctx->in + 64 - t, buf, t);
  93     byteSwap(ctx->in, 16);
  94     MD5Transform(ctx->buf, ctx->in);
  95     buf += t;
  96     len -= t;
  97
  98     /* Process data in 64-byte chunks */
  99     while (len >= 64)
 100     {
 101         memcpy(ctx->in, buf, 64);
 102         byteSwap(ctx->in, 16);
 103         MD5Transform(ctx->buf, ctx->in);
 104         buf += 64;
 105         len -= 64;
 106     }
 107
 108     /* Handle any remaining bytes of data. */
 109     memcpy(ctx->in, buf, len);
 110 }
 111
 112 /*
 113  * Final wrapup - pad to 64-byte boundary with the bit pattern
 114  * 1 0* (64-bit count of bits processed, MSB-first)
 115  */
 116 void
 117 MD5Final(md5byte digest[16], struct MD5Context *ctx)
 118 {
 119     int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */
 120     md5byte *p = (md5byte *)ctx->in + count;
 121
 122     /* Set the first char of padding to 0x80.  There is always room. */
 123     *p++ = 0x80;
 124
 125     /* Bytes of padding needed to make 56 bytes (-8..55) */
 126     count = 56 - 1 - count;
 127
 128     if (count < 0)    /* Padding forces an extra block */
 129     {
 130         memset(p, 0, count + 8);
 131         byteSwap(ctx->in, 16);
 132         MD5Transform(ctx->buf, ctx->in);
 133         p = (md5byte *)ctx->in;
 134         count = 56;
 135     }
 136
 137     memset(p, 0, count);
 138     byteSwap(ctx->in, 14);
 139
 140     /* Append length in bits and transform */
 141     ctx->in[14] = ctx->bytes[0] << 3;
 142     ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
 143     MD5Transform(ctx->buf, ctx->in);
 144
 145     byteSwap(ctx->buf, 4);
 146     memcpy(digest, ctx->buf, 16);
 147     memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
 148 }
 149
 150 #ifndef ASM_MD5
 151
 152 /* The four core functions - F1 is optimized somewhat */
 153
 154 /* #define F1(x, y, z) (x & y | ~x & z) */
 155 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 156 #define F2(x, y, z) F1(z, x, y)
 157 #define F3(x, y, z) (x ^ y ^ z)
 158 #define F4(x, y, z) (y ^ (x | ~z))
 159
 160 /* This is the central step in the MD5 algorithm. */
 161 #define MD5STEP(f,w,x,y,z,in,s) \
 162     (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
 163
 164 /*
 165  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 166  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 167  * the data and converts bytes into longwords for this routine.
 168  */
 169 void
 170 MD5Transform(UWORD32 buf[4], UWORD32 const in[16])
 171 {
 172     register UWORD32 a, b, c, d;
 173
 174     a = buf[0];
 175     b = buf[1];
 176     c = buf[2];
 177     d = buf[3];
 178
 179     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 180     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 181     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 182     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 183     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 184     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 185     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 186     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 187     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 188     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 189     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 190     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 191     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 192     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 193     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 194     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 195
 196     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 197     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 198     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 199     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 200     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 201     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 202     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 203     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 204     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 205     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 206     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 207     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 208     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 209     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 210     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 211     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 212
 213     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 214     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 215     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 216     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 217     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 218     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 219     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 220     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 221     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 222     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 223     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 224     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 225     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 226     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 227     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 228     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 229
 230     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 231     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 232     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 233     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 234     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 235     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 236     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 237     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 238     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 239     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 240     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 241     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 242     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 243     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 244     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 245     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 246
 247     buf[0] += a;
 248     buf[1] += b;
 249     buf[2] += c;
 250     buf[3] += d;
 251 }
 252
 253 #endif