src/util/md5.c

   1 /** MD5 implementation (RFC 1321)
   2  * @file
   3  *
   4  * This code implements the MD5 message-digest algorithm. The algorithm is due
   5  * to Ron Rivest.
   6  *
   7  * This code was written by Colin Plumb in 1993, no copyright is claimed.  This
   8  * code is in the public domain; do with it what you wish.
   9  *
  10  * This code was slightly modified to fit into Samba by abartlet@samba.org Jun
  11  * 2001 and to fit the cifs vfs by Steve French sfrench@us.ibm.com. Grabbed from
  12  * linux-2.6.9 one November afternoon 2004 and ELinksified' by jonas.
  13  *
  14  * Equivalent code is available from RSA Data Security, Inc.  This code has been
  15  * tested against that, and is equivalent, except that you don't need to include
  16  * two pages of legalese with every copy. */
  17
  18 #ifdef HAVE_CONFIG_H
  19 #include "config.h"
  20 #endif
  21
  22 #include <string.h>
  23
  24 #include "elinks.h"
  25
  26 #include "util/md5.h"
  27
  28 static void transform_md5(uint32_t buf[4], uint32_t const in[16]);
  29
  30 /** Swap the bytes of each uint32_t, if necessary.
  31  * This code is harmless on little-endian machines.
  32  * @todo FIXME: Optimize it away on little-endian machines. */
  33 static void
  34 reverse_md5_bytes(unsigned char *buf, unsigned int longs)
  35 {
  36         uint32_t t;
  37
  38         do {
  39                 t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  40                     ((unsigned) buf[1] << 8 | buf[0]);
  41                 *(uint32_t *) buf = t;
  42                 buf += 4;
  43         } while (--longs);
  44 }
  45
  46 /** Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
  47  * initialization constants.
  48  * @relates md5_context */
  49 void
  50 init_md5(struct md5_context *ctx)
  51 {
  52         ctx->buf[0] = 0x67452301;
  53         ctx->buf[1] = 0xefcdab89;
  54         ctx->buf[2] = 0x98badcfe;
  55         ctx->buf[3] = 0x10325476;
  56
  57         ctx->bits[0] = 0;
  58         ctx->bits[1] = 0;
  59 }
  60
  61 /** Update context to reflect the concatenation of another buffer full
  62  * of bytes.
  63  * @relates md5_context */
  64 void
  65 update_md5(struct md5_context *ctx, const unsigned char *buf, unsigned long len)
  66 {
  67         register uint32_t t;
  68
  69         /* Update bitcount */
  70
  71         t = ctx->bits[0];
  72         if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  73                 ctx->bits[1]++; /* Carry from low to high */
  74         ctx->bits[1] += len >> 29;
  75
  76         t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
  77
  78         /* Handle any leading odd-sized chunks */
  79
  80         if (t) {
  81                 unsigned char *p = (unsigned char *) ctx->in + t;
  82
  83                 t = 64 - t;
  84                 if (len < t) {
  85                         memmove(p, buf, len);
  86                         return;
  87                 }
  88                 memmove(p, buf, t);
  89                 reverse_md5_bytes(ctx->in, 16);
  90                 transform_md5(ctx->buf, (uint32_t *) ctx->in);
  91                 buf += t;
  92                 len -= t;
  93         }
  94
  95         /* Process data in 64-byte chunks */
  96
  97         while (len >= 64) {
  98                 memmove(ctx->in, buf, 64);
  99                 reverse_md5_bytes(ctx->in, 16);
 100                 transform_md5(ctx->buf, (uint32_t *) ctx->in);
 101                 buf += 64;
 102                 len -= 64;
 103         }
 104
 105         /* Handle any remaining bytes of data. */
 106
 107         memmove(ctx->in, buf, len);
 108 }
 109
 110 /** Final wrapup - pad to 64-byte boundary with the bit pattern 1 0* (64-bit
 111  * count of bits processed, MSB-first)
 112  * @relates md5_context */
 113 void
 114 done_md5(struct md5_context *ctx, md5_digest_bin_T digest)
 115 {
 116         unsigned int count;
 117         unsigned char *p;
 118
 119         /* Compute number of bytes mod 64 */
 120         count = (ctx->bits[0] >> 3) & 0x3F;
 121
 122         /* Set the first char of padding to 0x80.  This is safe since there is
 123            always at least one byte free */
 124         p = ctx->in + count;
 125         *p++ = 0x80;
 126
 127         /* Bytes of padding needed to make 64 bytes */
 128         count = 64 - 1 - count;
 129
 130         /* Pad out to 56 mod 64 */
 131         if (count < 8) {
 132                 /* Two lots of padding:  Pad the first block to 64 bytes */
 133                 memset(p, 0, count);
 134                 reverse_md5_bytes(ctx->in, 16);
 135                 transform_md5(ctx->buf, (uint32_t *) ctx->in);
 136
 137                 /* Now fill the next block with 56 bytes */
 138                 memset(ctx->in, 0, 56);
 139         } else {
 140                 /* Pad block to 56 bytes */
 141                 memset(p, 0, count - 8);
 142         }
 143
 144         reverse_md5_bytes(ctx->in, 14);
 145
 146         /* Append length in bits and transform */
 147         ((uint32_t *) ctx->in)[14] = ctx->bits[0];
 148         ((uint32_t *) ctx->in)[15] = ctx->bits[1];
 149
 150         transform_md5(ctx->buf, (uint32_t *) ctx->in);
 151         reverse_md5_bytes((unsigned char *) ctx->buf, 4);
 152         memmove(digest, ctx->buf, 16);
 153         memset(ctx, 0, sizeof(*ctx));   /* In case it's sensitive */
 154 }
 155
 156 unsigned char *
 157 digest_md5(const unsigned char *data, unsigned long length,
 158            md5_digest_bin_T digest)
 159 {
 160         struct md5_context ctx;
 161
 162         init_md5(&ctx);
 163
 164         if (length != 0)
 165                 update_md5(&ctx, data, length);
 166
 167         done_md5(&ctx, digest);
 168
 169         return digest;
 170 }
 171
 172 /* The four core functions - F1 is optimized somewhat */
 173
 174 /* #define F1(x, y, z) (x & y | ~x & z) */
 175 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 176 #define F2(x, y, z) F1(z, x, y)
 177 #define F3(x, y, z) (x ^ y ^ z)
 178 #define F4(x, y, z) (y ^ (x | ~z))
 179
 180 /** This is the central step in the MD5 algorithm. */
 181 #define MD5STEP(f, w, x, y, z, data, s) \
 182         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 183
 184 /** The core of the MD5 algorithm, this alters an existing MD5 hash to reflect
 185  * the addition of 16 longwords of new data. md5_update() blocks the data and
 186  * converts bytes into longwords for this routine. */
 187 static void
 188 transform_md5(uint32_t buf[4], uint32_t const in[16])
 189 {
 190         register uint32_t a, b, c, d;
 191
 192         a = buf[0];
 193         b = buf[1];
 194         c = buf[2];
 195         d = buf[3];
 196
 197         MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478,  7);
 198         MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
 199         MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17);
 200         MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
 201         MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf,  7);
 202         MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
 203         MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
 204         MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
 205         MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8,  7);
 206         MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
 207         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 208         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 209         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122,  7);
 210         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 211         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 212         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 213
 214         MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562,  5);
 215         MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340,  9);
 216         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 217         MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
 218         MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d,  5);
 219         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453,  9);
 220         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 221         MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
 222         MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6,  5);
 223         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6,  9);
 224         MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
 225         MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
 226         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905,  5);
 227         MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8,  9);
 228         MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
 229         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 230
 231         MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942,  4);
 232         MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
 233         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 234         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 235         MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44,  4);
 236         MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
 237         MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
 238         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 239         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6,  4);
 240         MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
 241         MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
 242         MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
 243         MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039,  4);
 244         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 245         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 246         MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23);
 247
 248         MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244,  6);
 249         MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10);
 250         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 251         MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21);
 252         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3,  6);
 253         MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10);
 254         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 255         MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21);
 256         MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f,  6);
 257         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 258         MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15);
 259         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 260         MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82,  6);
 261         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 262         MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15);
 263         MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21);
 264
 265         buf[0] += a;
 266         buf[1] += b;
 267         buf[2] += c;
 268         buf[3] += d;
 269 }