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 #include <string.h>             /* for memcpy() */
  18
  19 #include "md5.h"
  20
  21 #if !defined(WORDS_BIGENDIAN)
  22 # define byteReverse(buf, len)  /* Nothing */
  23 #else
  24 static void byteReverse(unsigned char *buf, unsigned longs);
  25
  26 #ifndef ASM_MD5
  27 /*
  28  * Note: this code is harmless on little-endian machines.
  29  */
  30 static void byteReverse(unsigned char *buf, unsigned longs)
  31 {
  32     uint32_t t;
  33     do {
  34         t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  35             ((unsigned) buf[1] << 8 | buf[0]);
  36         *(uint32_t *) buf = t;
  37         buf += 4;
  38     } while (--longs);
  39 }
  40 #endif /* !ASM_MD5 */
  41 #endif /* !WORDS_BIGENDIAN */
  42
  43 /*
  44  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  45  * initialization constants.
  46  */
  47 void ul_MD5Init(struct UL_MD5Context *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 /*
  59  * Update context to reflect the concatenation of another buffer full
  60  * of bytes.
  61  */
  62 void ul_MD5Update(struct UL_MD5Context *ctx, unsigned char const *buf, unsigned len)
  63 {
  64     uint32_t t;
  65
  66     /* Update bitcount */
  67
  68     t = ctx->bits[0];
  69     if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  70         ctx->bits[1]++;         /* Carry from low to high */
  71     ctx->bits[1] += len >> 29;
  72
  73     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
  74
  75     /* Handle any leading odd-sized chunks */
  76
  77     if (t) {
  78         unsigned char *p = (unsigned char *) ctx->in + t;
  79
  80         t = 64 - t;
  81         if (len < t) {
  82             memcpy(p, buf, len);
  83             return;
  84         }
  85         memcpy(p, buf, t);
  86         byteReverse(ctx->in, 16);
  87         ul_MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  88         buf += t;
  89         len -= t;
  90     }
  91     /* Process data in 64-byte chunks */
  92
  93     while (len >= 64) {
  94         memcpy(ctx->in, buf, 64);
  95         byteReverse(ctx->in, 16);
  96         ul_MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  97         buf += 64;
  98         len -= 64;
  99     }
 100
 101     /* Handle any remaining bytes of data. */
 102
 103     memcpy(ctx->in, buf, len);
 104 }
 105
 106 /*
 107  * Final wrapup - pad to 64-byte boundary with the bit pattern
 108  * 1 0* (64-bit count of bits processed, MSB-first)
 109  */
 110 void ul_MD5Final(unsigned char digest[UL_MD5LENGTH], struct UL_MD5Context *ctx)
 111 {
 112     unsigned count;
 113     unsigned char *p;
 114
 115     /* Compute number of bytes mod 64 */
 116     count = (ctx->bits[0] >> 3) & 0x3F;
 117
 118     /* Set the first char of padding to 0x80.  This is safe since there is
 119        always at least one byte free */
 120     p = ctx->in + count;
 121     *p++ = 0x80;
 122
 123     /* Bytes of padding needed to make 64 bytes */
 124     count = 64 - 1 - count;
 125
 126     /* Pad out to 56 mod 64 */
 127     if (count < 8) {
 128         /* Two lots of padding:  Pad the first block to 64 bytes */
 129         memset(p, 0, count);
 130         byteReverse(ctx->in, 16);
 131         ul_MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 132
 133         /* Now fill the next block with 56 bytes */
 134         memset(ctx->in, 0, 56);
 135     } else {
 136         /* Pad block to 56 bytes */
 137         memset(p, 0, count - 8);
 138     }
 139     byteReverse(ctx->in, 14);
 140
 141     /* Append length in bits and transform.
 142      * Use memcpy to avoid aliasing problems.  On most systems,
 143      * this will be optimized away to the same code.
 144      */
 145     memcpy(&ctx->in[14 * sizeof(uint32_t)], &ctx->bits[0], 4);
 146     memcpy(&ctx->in[15 * sizeof(uint32_t)], &ctx->bits[1], 4);
 147
 148     ul_MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 149     byteReverse((unsigned char *) ctx->buf, 4);
 150     memcpy(digest, ctx->buf, UL_MD5LENGTH);
 151     memset(ctx, 0, sizeof(*ctx));       /* In case it's sensitive */
 152 }
 153
 154 #ifndef ASM_MD5
 155
 156 /* The four core functions - F1 is optimized somewhat */
 157
 158 /* #define F1(x, y, z) (x & y | ~x & z) */
 159 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 160 #define F2(x, y, z) F1(z, x, y)
 161 #define F3(x, y, z) (x ^ y ^ z)
 162 #define F4(x, y, z) (y ^ (x | ~z))
 163
 164 /* This is the central step in the MD5 algorithm. */
 165 #define MD5STEP(f, w, x, y, z, data, s) \
 166         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 167
 168 /*
 169  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 170  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 171  * the data and converts bytes into longwords for this routine.
 172  */
 173 void ul_MD5Transform(uint32_t buf[4], uint32_t const in[16])
 174 {
 175     register uint32_t a, b, c, d;
 176
 177     a = buf[0];
 178     b = buf[1];
 179     c = buf[2];
 180     d = buf[3];
 181
 182     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 183     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 184     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 185     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 186     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 187     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 188     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 189     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 190     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 191     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 192     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 193     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 194     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 195     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 196     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 197     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 198
 199     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 200     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 201     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 202     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 203     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 204     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 205     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 206     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 207     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 208     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 209     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 210     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 211     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 212     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 213     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 214     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 215
 216     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 217     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 218     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 219     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 220     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 221     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 222     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 223     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 224     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 225     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 226     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 227     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 228     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 229     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 230     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 231     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 232
 233     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 234     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 235     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 236     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 237     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 238     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 239     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 240     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 241     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 242     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 243     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 244     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 245     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 246     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 247     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 248     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 249
 250     buf[0] += a;
 251     buf[1] += b;
 252     buf[2] += c;
 253     buf[3] += d;
 254 }
 255
 256 #endif
 257