wbMD5.h

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 *
 * Changed so as no longer to depend on Colin Plumb's `usual.h' header
 * definitions; now uses stuff from dpkg's config.h.
 *  - Ian Jackson <ian@chiark.greenend.org.uk>.
 * Still in the public domain.
 */

#ifndef __WB_MD5_H__
#define __WB_MD5_H__

#include <string.h>    /* for memcpy() */
#include <sys/types.h> /* for stupid systems */

#define UWORD32 unsigned int

#define md5byte unsigned char

struct MD5Context {
  UWORD32 buf[4];
  UWORD32 bytes[2];
  UWORD32 in[16];
};

static void MD5Init(struct MD5Context *context);
static void MD5Update(struct MD5Context *context, md5byte const *buf,
                      unsigned len);
static void MD5Final(unsigned char digest[16], struct MD5Context *context);
static void MD5Buffer(const unsigned char *buf, unsigned int len,
                      unsigned char sig[16]);
static void MD5SigToString(unsigned char sig[16], char *str, int len);

static void MD5Transform(UWORD32 buf[4], UWORD32 const in[16]);

static int g_bigEndian = 0;
static int g_endianessDetected = 0;

static void detectEndianess() {
  int nl = 0x12345678;
  short ns = 0x1234;

  unsigned char *p = (unsigned char *)(&nl);
  unsigned char *sp = (unsigned char *)(&ns);

  if (g_endianessDetected)
    return;
  if (p[0] == 0x12 && p[1] == 0x34 && p[2] == 0x56 && p[3] == 0x78) {
    g_bigEndian = 1;
  } else if (p[0] == 0x78 && p[1] == 0x56 && p[2] == 0x34 && p[3] == 0x12) {
    g_bigEndian = 0;
  } else {
    g_bigEndian = *sp != 0x12;
  }

  g_endianessDetected = 1;
}

static void byteSwap(UWORD32 *buf, unsigned words) {
  md5byte *p;

  if (!g_bigEndian)
    return;

  p = (md5byte *)buf;

  do {
    *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
             ((unsigned)p[1] << 8 | p[0]);
    p += 4;
  } while (--words);
}

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
static void MD5Init(struct MD5Context *ctx) {
  detectEndianess();

  ctx->buf[0] = 0x67452301;
  ctx->buf[1] = 0xefcdab89;
  ctx->buf[2] = 0x98badcfe;
  ctx->buf[3] = 0x10325476;

  ctx->bytes[0] = 0;
  ctx->bytes[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
static void MD5Update(struct MD5Context *ctx, md5byte const *buf,
                      unsigned len) {
  UWORD32 t;

  /* Update byte count */

  t = ctx->bytes[0];
  if ((ctx->bytes[0] = t + len) < t)
    ctx->bytes[1]++; /* Carry from low to high */

  t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */
  if (t > len) {
    memcpy((md5byte *)ctx->in + 64 - t, buf, len);
    return;
  }
  /* First chunk is an odd size */
  memcpy((md5byte *)ctx->in + 64 - t, buf, t);
  byteSwap(ctx->in, 16);
  MD5Transform(ctx->buf, ctx->in);
  buf += t;
  len -= t;

  /* Process data in 64-byte chunks */
  while (len >= 64) {
    memcpy(ctx->in, buf, 64);
    byteSwap(ctx->in, 16);
    MD5Transform(ctx->buf, ctx->in);
    buf += 64;
    len -= 64;
  }

  /* Handle any remaining bytes of data. */
  memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5Final(md5byte digest[16], struct MD5Context *ctx) {
  int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */
  md5byte *p = (md5byte *)ctx->in + count;

  /* Set the first char of padding to 0x80.  There is always room. */
  *p++ = 0x80;

  /* Bytes of padding needed to make 56 bytes (-8..55) */
  count = 56 - 1 - count;

  if (count < 0) { /* Padding forces an extra block */
    memset(p, 0, count + 8);
    byteSwap(ctx->in, 16);
    MD5Transform(ctx->buf, ctx->in);
    p = (md5byte *)ctx->in;
    count = 56;
  }
  memset(p, 0, count);
  byteSwap(ctx->in, 14);

  /* Append length in bits and transform */
  ctx->in[14] = ctx->bytes[0] << 3;
  ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
  MD5Transform(ctx->buf, ctx->in);

  byteSwap(ctx->buf, 4);
  memcpy(digest, ctx->buf, 16);
  memset(&ctx, 0, sizeof(ctx)); /* In case it's sensitive */
}

#ifndef ASM_MD5

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, in, s)                                          \
  (w += f(x, y, z) + in, w = (w << s | w >> (32 - s)) + x)

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void MD5Transform(UWORD32 buf[4], UWORD32 const in[16]) {
  register UWORD32 a, b, c, d;

  a = buf[0];
  b = buf[1];
  c = buf[2];
  d = buf[3];

  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

  buf[0] += a;
  buf[1] += b;
  buf[2] += c;
  buf[3] += d;
}

#endif

static void MD5_buffer(const unsigned char *buf, unsigned int len,
                       unsigned char sig[16]) {
  struct MD5Context md5;
  MD5Init(&md5);
  MD5Update(&md5, buf, len);
  MD5Final(sig, &md5);
}

#define wbMD5 MD5_buffer

#define HEX_STRING "0123456789abcdef" /* to convert to hex */

static void wbMD5_sigToString(unsigned char signature[16], char *str, int len) {
  unsigned char *sig_p;
  char *str_p, *max_p;
  unsigned int high, low;

  str_p = str;
  max_p = str + len;

  for (sig_p = (unsigned char *)signature;
       sig_p < (unsigned char *)signature + 16; sig_p++) {
    high = *sig_p / 16;
    low = *sig_p % 16;
    /* account for 2 chars */
    if (str_p + 1 >= max_p) {
      break;
    }
    *str_p++ = HEX_STRING[high];
    *str_p++ = HEX_STRING[low];
  }
  /* account for 2 chars */
  if (str_p < max_p) {
    *str_p++ = '\0';
  }
}

#endif /* __WB_MD5_H__ */