md5.c

/*
 * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
 * MD5 Message-Digest Algorithm (RFC 1321).
 *
 * Homepage:
 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5
 *
 * Author:
 * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
 *
 * This software was written by Alexander Peslyak in 2001.  No copyright is
 * claimed, and the software is hereby placed in the public domain.
 * In case this attempt to disclaim copyright and place the software in the
 * public domain is deemed null and void, then the software is
 * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
 * general public under the following terms:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted.
 *
 * There's ABSOLUTELY NO WARRANTY, express or implied.
 *
 * (This is a heavily cut-down "BSD license".)
 *
 * This differs from Colin Plumb's older public domain implementation in that
 * no exactly 32-bit integer data type is required (any 32-bit or wider
 * unsigned integer data type will do), there's no compile-time endianness
 * configuration, and the function prototypes match OpenSSL's.  No code from
 * Colin Plumb's implementation has been reused; this comment merely compares
 * the properties of the two independent implementations.
 *
 * The primary goals of this implementation are portability and ease of use.
 * It is meant to be fast, but not as fast as possible.  Some known
 * optimizations are not included to reduce source code size and avoid
 * compile-time configuration.
 */
 
#include <string.h>
 
#include <winpr/cast.h>
 
#include "md5.h"
 
/*
 * The basic MD5 functions.
 *
 * F and G are optimized compared to their RFC 1321 definitions for
 * architectures that lack an AND-NOT instruction, just like in Colin Plumb's
 * implementation.
 */
static inline winpr_MD5_u32plus F(winpr_MD5_u32plus x, winpr_MD5_u32plus y, winpr_MD5_u32plus z)
{
  return ((z) ^ ((x) & ((y) ^ (z))));
}
static inline winpr_MD5_u32plus G(winpr_MD5_u32plus x, winpr_MD5_u32plus y, winpr_MD5_u32plus z)
{
  return ((y) ^ ((z) & ((x) ^ (y))));
}
static inline winpr_MD5_u32plus H(winpr_MD5_u32plus x, winpr_MD5_u32plus y, winpr_MD5_u32plus z)
{
  return (((x) ^ (y)) ^ (z));
}
static inline winpr_MD5_u32plus H2(winpr_MD5_u32plus x, winpr_MD5_u32plus y, winpr_MD5_u32plus z)
{
  return ((x) ^ ((y) ^ (z)));
}
static inline winpr_MD5_u32plus I(winpr_MD5_u32plus x, winpr_MD5_u32plus y, winpr_MD5_u32plus z)
{
  return ((y) ^ ((x) | ~(z)));
}
 
/*
 * The MD5 transformation for all four rounds.
 */
#define STEP(f, a, b, c, d, x, t, s)                         \
  (a) += f((b), (c), (d)) + (x) + (t);                     \
  (a) = (((a) << (s)) | (((a)&0xffffffff) >> (32 - (s)))); \
  (a) += (b);
 
/*
 * SET reads 4 input bytes in little-endian byte order and stores them in a
 * properly aligned word in host byte order.
 *
 * The check for little-endian architectures that tolerate unaligned memory
 * accesses is just an optimization.  Nothing will break if it fails to detect
 * a suitable architecture.
 *
 * Unfortunately, this optimization may be a C strict aliasing rules violation
 * if the caller's data buffer has effective type that cannot be aliased by
 * MD5_u32plus.  In practice, this problem may occur if these MD5 routines are
 * inlined into a calling function, or with future and dangerously advanced
 * link-time optimizations.  For the time being, keeping these MD5 routines in
 * their own translation unit avoids the problem.
 */
#define SET(n)                                                          \
  (ctx->block[(n)] = (winpr_MD5_u32plus)ptr[4ULL * (n)] |             \
                     ((winpr_MD5_u32plus)ptr[4ULL * (n) + 1] << 8) |  \
                     ((winpr_MD5_u32plus)ptr[4ULL * (n) + 2] << 16) | \
                     ((winpr_MD5_u32plus)ptr[4ULL * (n) + 3] << 24))
#define GET(n) (ctx->block[(n)])
 
/*
 * This processes one or more 64-byte data blocks, but does NOT update the bit
 * counters.  There are no alignment requirements.
 */
static const void* body(WINPR_MD5_CTX* ctx, const void* data, size_t size)
{
  const unsigned char* ptr = (const unsigned char*)data;
 
  winpr_MD5_u32plus a = ctx->a;
  winpr_MD5_u32plus b = ctx->b;
  winpr_MD5_u32plus c = ctx->c;
  winpr_MD5_u32plus d = ctx->d;
 
  do
  {
    const winpr_MD5_u32plus saved_a = a;
    const winpr_MD5_u32plus saved_b = b;
    const winpr_MD5_u32plus saved_c = c;
    const winpr_MD5_u32plus saved_d = d;
 
    /* Round 1 */
    STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7)
    STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12)
    STEP(F, c, d, a, b, SET(2), 0x242070db, 17)
    STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22)
    STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7)
    STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12)
    STEP(F, c, d, a, b, SET(6), 0xa8304613, 17)
    STEP(F, b, c, d, a, SET(7), 0xfd469501, 22)
    STEP(F, a, b, c, d, SET(8), 0x698098d8, 7)
    STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12)
    STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17)
    STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22)
    STEP(F, a, b, c, d, SET(12), 0x6b901122, 7)
    STEP(F, d, a, b, c, SET(13), 0xfd987193, 12)
    STEP(F, c, d, a, b, SET(14), 0xa679438e, 17)
    STEP(F, b, c, d, a, SET(15), 0x49b40821, 22)
 
    /* Round 2 */
    STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5)
    STEP(G, d, a, b, c, GET(6), 0xc040b340, 9)
    STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14)
    STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20)
    STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5)
    STEP(G, d, a, b, c, GET(10), 0x02441453, 9)
    STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14)
    STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20)
    STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5)
    STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9)
    STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14)
    STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20)
    STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5)
    STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9)
    STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14)
    STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20)
 
    /* Round 3 */
    STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4)
    STEP(H2, d, a, b, c, GET(8), 0x8771f681, 11)
    STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
    STEP(H2, b, c, d, a, GET(14), 0xfde5380c, 23)
    STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
    STEP(H2, d, a, b, c, GET(4), 0x4bdecfa9, 11)
    STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
    STEP(H2, b, c, d, a, GET(10), 0xbebfbc70, 23)
    STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
    STEP(H2, d, a, b, c, GET(0), 0xeaa127fa, 11)
    STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
    STEP(H2, b, c, d, a, GET(6), 0x04881d05, 23)
    STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
    STEP(H2, d, a, b, c, GET(12), 0xe6db99e5, 11)
    STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
    STEP(H2, b, c, d, a, GET(2), 0xc4ac5665, 23)
 
    /* Round 4 */
    STEP(I, a, b, c, d, GET(0), 0xf4292244, 6)
    STEP(I, d, a, b, c, GET(7), 0x432aff97, 10)
    STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15)
    STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21)
    STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6)
    STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10)
    STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15)
    STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21)
    STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6)
    STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10)
    STEP(I, c, d, a, b, GET(6), 0xa3014314, 15)
    STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21)
    STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6)
    STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10)
    STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15)
    STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21)
 
    a += saved_a;
    b += saved_b;
    c += saved_c;
    d += saved_d;
 
    ptr += 64;
  } while (size -= 64);
 
  ctx->a = a;
  ctx->b = b;
  ctx->c = c;
  ctx->d = d;
 
  return ptr;
}
 
void winpr_MD5_Init(WINPR_MD5_CTX* ctx)
{
  ctx->a = 0x67452301;
  ctx->b = 0xefcdab89;
  ctx->c = 0x98badcfe;
  ctx->d = 0x10325476;
 
  ctx->lo = 0;
  ctx->hi = 0;
}
 
void winpr_MD5_Update(WINPR_MD5_CTX* ctx, const void* data, size_t size)
{
  winpr_MD5_u32plus saved_lo = ctx->lo;
  if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
    ctx->hi++;
  ctx->hi += (winpr_MD5_u32plus)((size >> 29) & 0xffffffff);
 
  size_t used = saved_lo & 0x3f;
 
  if (used)
  {
    size_t available = 64 - used;
 
    if (size < available)
    {
      memcpy(&ctx->buffer[used], data, size);
      return;
    }
 
    memcpy(&ctx->buffer[used], data, available);
    data = (const unsigned char*)data + available;
    size -= available;
    body(ctx, ctx->buffer, 64);
  }
 
  if (size >= 64)
  {
    data = body(ctx, data, size & ~(size_t)0x3f);
    size &= 0x3f;
  }
 
  memcpy(ctx->buffer, data, size);
}
 
static inline void mdOUT(unsigned char* dst, winpr_MD5_u32plus src)
{
  (dst)[0] = (unsigned char)(src);
  (dst)[1] = (unsigned char)((src) >> 8);
  (dst)[2] = (unsigned char)((src) >> 16);
  (dst)[3] = (unsigned char)((src) >> 24);
}
 
void winpr_MD5_Final(unsigned char* result, WINPR_MD5_CTX* ctx)
{
  size_t used = ctx->lo & 0x3f;
 
  ctx->buffer[used++] = 0x80;
 
  size_t available = 64 - used;
 
  if (available < 8)
  {
    memset(&ctx->buffer[used], 0, available);
    body(ctx, ctx->buffer, 64);
    used = 0;
    available = 64;
  }
 
  memset(&ctx->buffer[used], 0, available - 8);
 
  ctx->lo <<= 3;
  mdOUT(&ctx->buffer[56], ctx->lo);
  mdOUT(&ctx->buffer[60], ctx->hi);
 
  body(ctx, ctx->buffer, 64);
 
  mdOUT(&result[0], ctx->a);
  mdOUT(&result[4], ctx->b);
  mdOUT(&result[8], ctx->c);
  mdOUT(&result[12], ctx->d);
 
  memset(ctx, 0, sizeof(*ctx));
}