utils/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  * Changed so as no longer to depend on Colin Plumb's `usual.h' header
  18  * definitions; now uses stuff from dpkg's config.h.
  19  *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
  20  * Still in the public domain.
  21  */
  22
  23 #include <string.h>
  24
  25 #include "md5.h"
  26
  27 #if (__BYTE_ORDER == __BIG_ENDIAN)
  28 /*
  29  * we can compile this away for little endian since
  30  * it does not do anything on those archs
  31  */
  32 void
  33 byteSwap(uint32_t * buf, unsigned words)
  34 {
  35         md5byte *p = (md5byte *) buf;
  36
  37         do {
  38                 *buf++ = (uint32_t) ((unsigned) p[3] << 8 | p[2]) << 16 |
  39                     ((unsigned) p[1] << 8 | p[0]);
  40                 p += 4;
  41         } while (--words);
  42 }
  43 #else
  44 #define byteSwap(buf,words)
  45 #endif
  46
  47 /*
  48  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  49  * initialization constants.
  50  */
  51 void
  52 MD5Init(struct MD5Context *ctx)
  53 {
  54         ctx->buf[0] = 0x67452301;
  55         ctx->buf[1] = 0xefcdab89;
  56         ctx->buf[2] = 0x98badcfe;
  57         ctx->buf[3] = 0x10325476;
  58
  59         ctx->bytes[0] = 0;
  60         ctx->bytes[1] = 0;
  61 }
  62
  63 /*
  64  * Update context to reflect the concatenation of another buffer full
  65  * of bytes.
  66  */
  67 void
  68 MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len)
  69 {
  70         uint32_t t;
  71
  72         /* Update byte count */
  73
  74         t = ctx->bytes[0];
  75         if ((ctx->bytes[0] = t + len) < t)
  76                 ctx->bytes[1]++;        /* Carry from low to high */
  77
  78         t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
  79         if (t > len) {
  80                 memcpy((md5byte *) ctx->in + 64 - t, buf, len);
  81                 return;
  82         }
  83         /* First chunk is an odd size */
  84         memcpy((md5byte *) ctx->in + 64 - t, buf, t);
  85         byteSwap(ctx->in, 16);
  86         MD5Transform(ctx->buf, ctx->in);
  87         buf += t;
  88         len -= t;
  89
  90         /* Process data in 64-byte chunks */
  91         while (len >= 64) {
  92                 memcpy(ctx->in, buf, 64);
  93                 byteSwap(ctx->in, 16);
  94                 MD5Transform(ctx->buf, ctx->in);
  95                 buf += 64;
  96                 len -= 64;
  97         }
  98
  99         /* Handle any remaining bytes of data. */
 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
 108 MD5Final(md5byte digest[16], struct MD5Context *ctx)
 109 {
 110         int count = ctx->bytes[0] & 0x3f;       /* Number of bytes in ctx->in */
 111         md5byte *p = (md5byte *) ctx->in + count;
 112
 113         /* Set the first char of padding to 0x80.  There is always room. */
 114         *p++ = 0x80;
 115
 116         /* Bytes of padding needed to make 56 bytes (-8..55) */
 117         count = 56 - 1 - count;
 118
 119         if (count < 0) {        /* Padding forces an extra block */
 120                 memset(p, 0, count + 8);
 121                 byteSwap(ctx->in, 16);
 122                 MD5Transform(ctx->buf, ctx->in);
 123                 p = (md5byte *) ctx->in;
 124                 count = 56;
 125         }
 126         memset(p, 0, count);
 127         byteSwap(ctx->in, 14);
 128
 129         /* Append length in bits and transform */
 130         ctx->in[14] = ctx->bytes[0] << 3;
 131         ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
 132         MD5Transform(ctx->buf, ctx->in);
 133
 134         byteSwap(ctx->buf, 4);
 135         memcpy(digest, ctx->buf, 16);
 136         memset(ctx, 0, sizeof (ctx));   /* In case it's sensitive */
 137 }
 138
 139 #ifndef ASM_MD5
 140
 141 /* The four core functions - F1 is optimized somewhat */
 142
 143 /* #define F1(x, y, z) (x & y | ~x & z) */
 144 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 145 #define F2(x, y, z) F1(z, x, y)
 146 #define F3(x, y, z) (x ^ y ^ z)
 147 #define F4(x, y, z) (y ^ (x | ~z))
 148
 149 /* This is the central step in the MD5 algorithm. */
 150 #define MD5STEP(f,w,x,y,z,in,s) \
 151          (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
 152
 153 /*
 154  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 155  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 156  * the data and converts bytes into longwords for this routine.
 157  */
 158 void
 159 MD5Transform(uint32_t buf[4], uint32_t const in[16])
 160 {
 161         register uint32_t a, b, c, d;
 162
 163         a = buf[0];
 164         b = buf[1];
 165         c = buf[2];
 166         d = buf[3];
 167
 168         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 169         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 170         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 171         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 172         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 173         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 174         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 175         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 176         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 177         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 178         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 179         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 180         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 181         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 182         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 183         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 184
 185         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 186         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 187         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 188         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 189         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 190         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 191         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 192         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 193         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 194         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 195         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 196         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 197         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 198         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 199         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 200         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 201
 202         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 203         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 204         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 205         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 206         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 207         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 208         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 209         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 210         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 211         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 212         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 213         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 214         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 215         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 216         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 217         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 218
 219         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 220         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 221         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 222         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 223         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 224         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 225         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 226         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 227         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 228         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 229         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 230         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 231         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 232         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 233         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 234         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 235
 236         buf[0] += a;
 237         buf[1] += b;
 238         buf[2] += c;
 239         buf[3] += d;
 240 }
 241
 242 #endif