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 /* This code was modified in 1997 by Jim Kingdon of Cyclic Software to
  19    not require an integer type which is exactly 32 bits.  This work
  20    draws on the changes for the same purpose by Tatu Ylonen
  21    <ylo@cs.hut.fi> as part of SSH, but since I didn't actually use
  22    that code, there is no copyright issue.  I hereby disclaim
  23    copyright in any changes I have made; this code remains in the
  24    public domain.  */
  25
  26 #include <string.h>     /* for memcpy() and memset() */
  27
  28 /* Add prototype support.  */
  29 #ifndef PROTO
  30 #if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__)
  31 #define PROTO(ARGS) ARGS
  32 #else
  33 #define PROTO(ARGS) ()
  34 #endif
  35 #endif
  36
  37 #include "md5.h"
  38
  39 /* Little-endian byte-swapping routines.  Note that these do not
  40    depend on the size of datatypes such as cvs_uint32, nor do they require
  41    us to detect the endianness of the machine we are running on.  It
  42    is possible they should be macros for speed, but I would be
  43    surprised if they were a performance bottleneck for MD5.  */
  44
  45 static uint32
  46 getu32 (addr)
  47      const unsigned char *addr;
  48 {
  49         return (((((unsigned long)addr[3] << 8) | addr[2]) << 8)
  50                 | addr[1]) << 8 | addr[0];
  51 }
  52
  53 static void
  54 putu32 (data, addr)
  55      uint32 data;
  56      unsigned char *addr;
  57 {
  58         addr[0] = (unsigned char)data;
  59         addr[1] = (unsigned char)(data >> 8);
  60         addr[2] = (unsigned char)(data >> 16);
  61         addr[3] = (unsigned char)(data >> 24);
  62 }
  63
  64 /*
  65  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  66  * initialization constants.
  67  */
  68 void
  69 MD5Init (ctx)
  70      struct MD5Context *ctx;
  71 {
  72         ctx->buf[0] = 0x67452301;
  73         ctx->buf[1] = 0xefcdab89;
  74         ctx->buf[2] = 0x98badcfe;
  75         ctx->buf[3] = 0x10325476;
  76
  77         ctx->bits[0] = 0;
  78         ctx->bits[1] = 0;
  79 }
  80
  81 /*
  82  * Update context to reflect the concatenation of another buffer full
  83  * of bytes.
  84  */
  85 void
  86 MD5Update (ctx, buf, len)
  87      struct MD5Context *ctx;
  88      unsigned char const *buf;
  89      unsigned len;
  90 {
  91         uint32 t;
  92
  93         /* Update bitcount */
  94
  95         t = ctx->bits[0];
  96         if ((ctx->bits[0] = (t + ((uint32)len << 3)) & 0xffffffff) < t)
  97                 ctx->bits[1]++; /* Carry from low to high */
  98         ctx->bits[1] += len >> 29;
  99
 100         t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
 101
 102         /* Handle any leading odd-sized chunks */
 103
 104         if ( t ) {
 105                 unsigned char *p = ctx->in + t;
 106
 107                 t = 64-t;
 108                 if (len < t) {
 109                         memcpy(p, buf, len);
 110                         return;
 111                 }
 112                 memcpy(p, buf, t);
 113                 MD5Transform (ctx->buf, ctx->in);
 114                 buf += t;
 115                 len -= t;
 116         }
 117
 118         /* Process data in 64-byte chunks */
 119
 120         while (len >= 64) {
 121                 memcpy(ctx->in, buf, 64);
 122                 MD5Transform (ctx->buf, ctx->in);
 123                 buf += 64;
 124                 len -= 64;
 125         }
 126
 127         /* Handle any remaining bytes of data. */
 128
 129         memcpy(ctx->in, buf, len);
 130 }
 131
 132 /*
 133  * Final wrapup - pad to 64-byte boundary with the bit pattern
 134  * 1 0* (64-bit count of bits processed, MSB-first)
 135  */
 136 void
 137 MD5Final (digest, ctx)
 138      unsigned char digest[16];
 139      struct MD5Context *ctx;
 140 {
 141         unsigned count;
 142         unsigned char *p;
 143
 144         /* Compute number of bytes mod 64 */
 145         count = (ctx->bits[0] >> 3) & 0x3F;
 146
 147         /* Set the first char of padding to 0x80.  This is safe since there is
 148            always at least one byte free */
 149         p = ctx->in + count;
 150         *p++ = 0x80;
 151
 152         /* Bytes of padding needed to make 64 bytes */
 153         count = 64 - 1 - count;
 154
 155         /* Pad out to 56 mod 64 */
 156         if (count < 8) {
 157                 /* Two lots of padding:  Pad the first block to 64 bytes */
 158                 memset(p, 0, count);
 159                 MD5Transform (ctx->buf, ctx->in);
 160
 161                 /* Now fill the next block with 56 bytes */
 162                 memset(ctx->in, 0, 56);
 163         } else {
 164                 /* Pad block to 56 bytes */
 165                 memset(p, 0, count-8);
 166         }
 167
 168         /* Append length in bits and transform */
 169         putu32(ctx->bits[0], ctx->in + 56);
 170         putu32(ctx->bits[1], ctx->in + 60);
 171
 172         MD5Transform (ctx->buf, ctx->in);
 173         putu32(ctx->buf[0], digest);
 174         putu32(ctx->buf[1], digest + 4);
 175         putu32(ctx->buf[2], digest + 8);
 176         putu32(ctx->buf[3], digest + 12);
 177         memset(ctx, 0, sizeof(MD5Context));     /* In case it's sensitive */
 178 }
 179
 180 /* The four core functions - F1 is optimized somewhat */
 181
 182 /* #define F1(x, y, z) (x & y | ~x & z) */
 183 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 184 #define F2(x, y, z) F1(z, x, y)
 185 #define F3(x, y, z) (x ^ y ^ z)
 186 #define F4(x, y, z) (y ^ (x | ~z))
 187
 188 /* This is the central step in the MD5 algorithm. */
 189 #define MD5STEP(f, w, x, y, z, data, s) \
 190         ( w += f(x, y, z) + data, w &= 0xffffffff, w = w<<s | w>>(32-s), w += x )
 191
 192 /*
 193  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 194  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 195  * the data and converts bytes into longwords for this routine.
 196  */
 197 void
 198 MD5Transform (buf, inraw)
 199      uint32 buf[4];
 200      const unsigned char inraw[64];
 201 {
 202         register uint32 a, b, c, d;
 203         uint32 in[16];
 204         int i;
 205
 206         for (i = 0; i < 16; ++i)
 207                 in[i] = getu32 (inraw + 4 * i);
 208
 209         a = buf[0];
 210         b = buf[1];
 211         c = buf[2];
 212         d = buf[3];
 213
 214         MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
 215         MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
 216         MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
 217         MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
 218         MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
 219         MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
 220         MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
 221         MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
 222         MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
 223         MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
 224         MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
 225         MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
 226         MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
 227         MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
 228         MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
 229         MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);
 230
 231         MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
 232         MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
 233         MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
 234         MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
 235         MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
 236         MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
 237         MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
 238         MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
 239         MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
 240         MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
 241         MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
 242         MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
 243         MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
 244         MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
 245         MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
 246         MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);
 247
 248         MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
 249         MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
 250         MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
 251         MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
 252         MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
 253         MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
 254         MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
 255         MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
 256         MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
 257         MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
 258         MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
 259         MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
 260         MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
 261         MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
 262         MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
 263         MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);
 264
 265         MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
 266         MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
 267         MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
 268         MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
 269         MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
 270         MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
 271         MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
 272         MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
 273         MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
 274         MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
 275         MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
 276         MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
 277         MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
 278         MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
 279         MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
 280         MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);
 281
 282         buf[0] += a;
 283         buf[1] += b;
 284         buf[2] += c;
 285         buf[3] += d;
 286 }