tor-browser

md5_utils.c (8265B)

---

/*
* 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
*  - Ian Jackson <ian@chiark.greenend.org.uk>.
* Still in the public domain.
*/

#include <string.h> /* for memcpy() */

#include "common/md5_utils.h"

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

 /* Only swap bytes for big endian machines */
 int i = 1;

 if (*(char *)&i == 1) 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.
*/
void MD5Init(struct MD5Context *ctx) {
 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.
*/
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)
*/
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)

#if defined(__clang__) && defined(__has_attribute)
#if __has_attribute(no_sanitize)
#define AOM_NO_UNSIGNED_OVERFLOW_CHECK \
 __attribute__((no_sanitize("unsigned-integer-overflow")))
#endif
#if __clang_major__ >= 12
#define VPX_NO_UNSIGNED_SHIFT_CHECK \
 __attribute__((no_sanitize("unsigned-shift-base")))
#endif  // __clang__ >= 12
#endif  // __clang__

#ifndef AOM_NO_UNSIGNED_OVERFLOW_CHECK
#define AOM_NO_UNSIGNED_OVERFLOW_CHECK
#endif
#ifndef AOM_NO_UNSIGNED_SHIFT_CHECK
#define AOM_NO_UNSIGNED_SHIFT_CHECK
#endif

/*
* 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.
*/
AOM_NO_UNSIGNED_OVERFLOW_CHECK AOM_NO_UNSIGNED_SHIFT_CHECK 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;
}

#undef AOM_NO_UNSIGNED_OVERFLOW_CHECK
#undef AOM_NO_UNSIGNED_SHIFT_CHECK

#endif