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md5.c

/*
 * $Id: md5.c,v 1.8 2006-12-13 00:49:14 heas Exp $
 *
 * Copyright (c) 1995-1998 by Cisco systems, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for
 * any purpose and without fee is hereby granted, provided that this
 * copyright and permission notice appear on all copies of the
 * software and supporting documentation, the name of Cisco Systems,
 * Inc. not be used in advertising or publicity pertaining to
 * distribution of the program without specific prior permission, and
 * notice be given in supporting documentation that modification,
 * copying and distribution is by permission of Cisco Systems, Inc.
 *
 * Cisco Systems, Inc. makes no representations about the suitability
 * of this software for any purpose.  THIS SOFTWARE IS PROVIDED ``AS
 * IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
 * md5c.c - RSA Data Security, Inc., MD5 message-digest algorithm
 */

/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
 * rights reserved.
 *
 * License to copy and use this software is granted provided that it
 * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
 * Algorithm" in all material mentioning or referencing this software
 * or this function.
 *
 * License is also granted to make and use derivative works provided
 * that such works are identified as "derived from the RSA Data
 * Security, Inc. MD5 Message-Digest Algorithm" in all material
 * mentioning or referencing the derived work.
 *
 * RSA Data Security, Inc. makes no representations concerning either
 * the merchantability of this software or the suitability of this
 * software for any particular purpose. It is provided "as is"
 * without express or implied warranty of any kind.
 *
 * These notices must be retained in any copies of any part of this
 * documentation and/or software.
 */

#include <config.h>
#ifdef HAVE_STRING_H
# include <string.h>
#endif

/*
 * RFC 1321 version #includes global.h, but md5.h has been locally modified
 * to contain all the information that RFC 1321's global.h contains.
 */

#include "md5.h"

#pragma     weak  MD5Final
#pragma     weak  MD5Init
#pragma     weak  MD5Update

/* Constants for MD5Transform routine. */

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform(uint32_t[4], unsigned char[64]);
static void Encode(unsigned char *, uint32_t *, unsigned int);
static void Decode(uint32_t *, unsigned char *, unsigned int);

#if !defined(MD5_NEED_MEM_FUNCS)

#define MD5_memcpy(out,in,len) memcpy(out, in, len)
#define MD5_memset(ptr,val,len) memset(ptr, val, len)

#else                   /* !defined(MD5_NEED_MEM_FUNCS) */

static void MD5_memcpy(POINTER, POINTER, unsigned int);
static void MD5_memset(POINTER, int, unsigned int);

#endif                        /* !defined(MD5_NEED_MEM_FUNCS) */

static unsigned char PADDING[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/*
 * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
 * Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

/* MD5 initialization. Begins an MD5 operation, writing a new context. */
void
MD5Init(MD5_CTX *context)
{
    context->count[0] = context->count[1] = 0;
    /* Load magic initialization constants. */
    context->state[0] = 0x67452301;
    context->state[1] = 0xefcdab89;
    context->state[2] = 0x98badcfe;
    context->state[3] = 0x10325476;
}

/*
 * MD5 block update operation. Continues an MD5 message-digest
 * operation, processing another message block, and updating the
 * context.
 */
void
MD5Update(MD5_CTX *context,               /* context */
        unsigned char *input,             /* input block */
        unsigned int inputLen)            /* length of input block */
{
    unsigned int i, nbytes, partLen;

    /* Compute number of bytes mod 64 */
    nbytes = (unsigned int) ((context->count[0] >> 3) & 0x3F);

    /* Update number of bits */
    if ((context->count[0] += ((uint32_t) inputLen << 3)) <
                                    ((uint32_t) inputLen << 3))
      context->count[1]++;
    context->count[1] += ((uint32_t) inputLen >> 29);

    partLen = 64 - nbytes;

    /* Transform as many times as possible. */
    if (inputLen >= partLen) {
      memcpy((POINTER) &context->buffer[nbytes], (POINTER) input, partLen);
      MD5Transform(context->state, context->buffer);

      for (i = partLen; i + 63 < inputLen; i += 64)
          MD5Transform(context->state, &input[i]);

      nbytes = 0;
    } else
      i = 0;

    /* Buffer remaining input */
    memcpy((POINTER) &context->buffer[nbytes], (POINTER) & input[i],
                                                inputLen - i);
}

/*
 * MD5 finalization. Ends an MD5 message-digest operation, writing the
 * message digest and zeroizing the context.
 */
void
MD5Final(unsigned char digest[16],        /* message digest */
       MD5_CTX *context)                  /* context */
{
    unsigned char bits[8];
    unsigned int nbytes, padLen;

    /* Save number of bits */
    Encode(bits, context->count, 8);

    /* Pad out to 56 mod 64. */
    nbytes = (unsigned int) ((context->count[0] >> 3) & 0x3f);
    padLen = (nbytes < 56) ? (56 - nbytes) : (120 - nbytes);
    MD5Update(context, PADDING, padLen);

    /* Append length (before padding) */
    MD5Update(context, bits, 8);

    /* Store state in digest */
    Encode(digest, context->state, 16);

    /* Zeroize sensitive information. */
    memset((POINTER) context, 0, sizeof(*context));
}

/* MD5 basic transformation. Transforms state based on block.
 */
static void
MD5Transform(uint32_t state[4], unsigned char block[64])
{
    uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

    Decode(x, block, 64);

    /* Round 1 */
    FF(a, b, c, d, x[0], S11, 0xd76aa478);      /* 1 */
    FF(d, a, b, c, x[1], S12, 0xe8c7b756);      /* 2 */
    FF(c, d, a, b, x[2], S13, 0x242070db);      /* 3 */
    FF(b, c, d, a, x[3], S14, 0xc1bdceee);      /* 4 */
    FF(a, b, c, d, x[4], S11, 0xf57c0faf);      /* 5 */
    FF(d, a, b, c, x[5], S12, 0x4787c62a);      /* 6 */
    FF(c, d, a, b, x[6], S13, 0xa8304613);      /* 7 */
    FF(b, c, d, a, x[7], S14, 0xfd469501);      /* 8 */
    FF(a, b, c, d, x[8], S11, 0x698098d8);      /* 9 */
    FF(d, a, b, c, x[9], S12, 0x8b44f7af);      /* 10 */
    FF(c, d, a, b, x[10], S13, 0xffff5bb1);     /* 11 */
    FF(b, c, d, a, x[11], S14, 0x895cd7be);     /* 12 */
    FF(a, b, c, d, x[12], S11, 0x6b901122);     /* 13 */
    FF(d, a, b, c, x[13], S12, 0xfd987193);     /* 14 */
    FF(c, d, a, b, x[14], S13, 0xa679438e);     /* 15 */
    FF(b, c, d, a, x[15], S14, 0x49b40821);     /* 16 */

    /* Round 2 */
    GG(a, b, c, d, x[1], S21, 0xf61e2562);      /* 17 */
    GG(d, a, b, c, x[6], S22, 0xc040b340);      /* 18 */
    GG(c, d, a, b, x[11], S23, 0x265e5a51);     /* 19 */
    GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);      /* 20 */
    GG(a, b, c, d, x[5], S21, 0xd62f105d);      /* 21 */
    GG(d, a, b, c, x[10], S22, 0x2441453);      /* 22 */
    GG(c, d, a, b, x[15], S23, 0xd8a1e681);     /* 23 */
    GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);      /* 24 */
    GG(a, b, c, d, x[9], S21, 0x21e1cde6);      /* 25 */
    GG(d, a, b, c, x[14], S22, 0xc33707d6);     /* 26 */
    GG(c, d, a, b, x[3], S23, 0xf4d50d87);      /* 27 */
    GG(b, c, d, a, x[8], S24, 0x455a14ed);      /* 28 */
    GG(a, b, c, d, x[13], S21, 0xa9e3e905);     /* 29 */
    GG(d, a, b, c, x[2], S22, 0xfcefa3f8);      /* 30 */
    GG(c, d, a, b, x[7], S23, 0x676f02d9);      /* 31 */
    GG(b, c, d, a, x[12], S24, 0x8d2a4c8a);     /* 32 */

    /* Round 3 */
    HH(a, b, c, d, x[5], S31, 0xfffa3942);      /* 33 */
    HH(d, a, b, c, x[8], S32, 0x8771f681);      /* 34 */
    HH(c, d, a, b, x[11], S33, 0x6d9d6122);     /* 35 */
    HH(b, c, d, a, x[14], S34, 0xfde5380c);     /* 36 */
    HH(a, b, c, d, x[1], S31, 0xa4beea44);      /* 37 */
    HH(d, a, b, c, x[4], S32, 0x4bdecfa9);      /* 38 */
    HH(c, d, a, b, x[7], S33, 0xf6bb4b60);      /* 39 */
    HH(b, c, d, a, x[10], S34, 0xbebfbc70);     /* 40 */
    HH(a, b, c, d, x[13], S31, 0x289b7ec6);     /* 41 */
    HH(d, a, b, c, x[0], S32, 0xeaa127fa);      /* 42 */
    HH(c, d, a, b, x[3], S33, 0xd4ef3085);      /* 43 */
    HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
    HH(a, b, c, d, x[9], S31, 0xd9d4d039);      /* 45 */
    HH(d, a, b, c, x[12], S32, 0xe6db99e5);     /* 46 */
    HH(c, d, a, b, x[15], S33, 0x1fa27cf8);     /* 47 */
    HH(b, c, d, a, x[2], S34, 0xc4ac5665);      /* 48 */

    /* Round 4 */
    II(a, b, c, d, x[0], S41, 0xf4292244);      /* 49 */
    II(d, a, b, c, x[7], S42, 0x432aff97);      /* 50 */
    II(c, d, a, b, x[14], S43, 0xab9423a7);     /* 51 */
    II(b, c, d, a, x[5], S44, 0xfc93a039);      /* 52 */
    II(a, b, c, d, x[12], S41, 0x655b59c3);     /* 53 */
    II(d, a, b, c, x[3], S42, 0x8f0ccc92);      /* 54 */
    II(c, d, a, b, x[10], S43, 0xffeff47d);     /* 55 */
    II(b, c, d, a, x[1], S44, 0x85845dd1);      /* 56 */
    II(a, b, c, d, x[8], S41, 0x6fa87e4f);      /* 57 */
    II(d, a, b, c, x[15], S42, 0xfe2ce6e0);     /* 58 */
    II(c, d, a, b, x[6], S43, 0xa3014314);      /* 59 */
    II(b, c, d, a, x[13], S44, 0x4e0811a1);     /* 60 */
    II(a, b, c, d, x[4], S41, 0xf7537e82);      /* 61 */
    II(d, a, b, c, x[11], S42, 0xbd3af235);     /* 62 */
    II(c, d, a, b, x[2], S43, 0x2ad7d2bb);      /* 63 */
    II(b, c, d, a, x[9], S44, 0xeb86d391);      /* 64 */

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

    /* Zeroize sensitive information. */
    memset((POINTER) x, 0, sizeof(x));
}

/*
 * Encodes input (uint32_t) into output (unsigned char). Assumes len is a
 * multiple of 4.
 */
static void
Encode(unsigned char *output, uint32_t *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4) {
      output[j] = (unsigned char) (input[i] & 0xff);
      output[j + 1] = (unsigned char) ((input[i] >> 8) & 0xff);
      output[j + 2] = (unsigned char) ((input[i] >> 16) & 0xff);
      output[j + 3] = (unsigned char) ((input[i] >> 24) & 0xff);
    }
}

/*
 * Decodes input (unsigned char) into output (uint32_t). Assumes len is a
 * multiple of 4.
 */
static void
Decode(uint32_t *output, unsigned char *input, unsigned int len)
{
    unsigned int i, j;

    for (i = 0, j = 0; j < len; i++, j += 4)
      output[i] = ((uint32_t) input[j]) | (((uint32_t) input[j + 1]) << 8) |
                (((uint32_t) input[j + 2]) << 16) |
                  (((uint32_t) input[j + 3]) << 24);
}

#if defined(MD5_NEED_MEM_FUNC)
/* Note: Replace "for loop" with standard memcpy if possible. */
static void
MD5_memcpy(POINTER output, POINTER input, unsigned int len)
{
    unsigned int i;

    for (i = 0; i < len; i++)
      output[i] = input[i];
}


/* Note: Replace "for loop" with standard memset if possible. */
static void
MD5_memset(POINTER output, int value, unsigned int len)
{
    unsigned int i;

    for (i = 0; i < len; i++)
      ((char *) output)[i] = (char) value;
}
#endif                        /* defined(MD5_NEED_MEM_FUNC) */

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