src/util/md5.c

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