Logo Search packages:      
Sourcecode: pan version File versions  Download package

md5-utils.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * 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 md5_init, call md5_update as
 * needed on buffers full of bytes, and then call md5_Final, which
 * will fill a supplied 16-byte array with the digest.
 */

/* parts of this file are:
 * Written March 1993 by Branko Lankester
 * Modified June 1993 by Colin Plumb for altered md5.c.
 * Modified October 1995 by Erik Troan for RPM
 */


#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include "md5-utils.h"

#include <glib/gmem.h>
#include <glib/garray.h>

#define d(x)

static void md5_transform (guint32 buf[4], const guint32 in[16]);

static int _ie = 0x44332211;
static union _endian { int i; char b[4]; } *_endian = (union _endian *)&_ie;
#define     IS_BIG_ENDIAN()         (_endian->b[0] == '\x44')
#define     IS_LITTLE_ENDIAN()      (_endian->b[0] == '\x11')


/*
 * Note: this code is harmless on little-endian machines.
 */
static void 
_byte_reverse (unsigned char *buf, guint32 longs)
{
      guint32 t;
      
      do {
            t = (guint32) ((guint32) buf[3] << 8 | buf[2]) << 16 |
                  ((guint32) buf[1] << 8 | buf[0]);
            *(guint32 *) buf = t;
            buf += 4;
      } while (--longs);
}


/**
 * md5_init: Initialise an md5 context object
 * @ctx: md5 context 
 * 
 * Initialise an md5 buffer. 
 *
 **/
void 
md5_init (MD5Context *ctx)
{
      ctx->buf[0] = 0x67452301;
      ctx->buf[1] = 0xefcdab89;
      ctx->buf[2] = 0x98badcfe;
      ctx->buf[3] = 0x10325476;
      
      ctx->bits[0] = 0;
      ctx->bits[1] = 0;
      
      if (IS_BIG_ENDIAN())    
            ctx->doByteReverse = 1;       
      else 
            ctx->doByteReverse = 0; 
}


/**
 * md5_update: add a buffer to md5 hash computation
 * @ctx: conetxt object used for md5 computaion
 * @buf: buffer to add
 * @len: buffer length
 * 
 * Update context to reflect the concatenation of another buffer full
 * of bytes. Use this to progressively construct an md5 hash.
 **/
void 
md5_update (MD5Context *ctx, const unsigned char *buf, guint32 len)
{
      guint32 t;
      
      /* Update bitcount */
      t = ctx->bits[0];
      if ((ctx->bits[0] = t + ((guint32) len << 3)) < t)
            ctx->bits[1]++;         /* Carry from low to high */
      ctx->bits[1] += len >> 29;
      
      t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
      
      /* Handle any leading odd-sized chunks */
      if (t) {
            unsigned char *p = (unsigned char *) ctx->in + t;
            
            t = 64 - t;
            if (len < t) {
                  memcpy (p, buf, len);
                  return;
            }
            memcpy (p, buf, t);
            if (ctx->doByteReverse)
                  _byte_reverse (ctx->in, 16);
            md5_transform (ctx->buf, (guint32 *) ctx->in);
            buf += t;
            len -= t;
      }
      
      /* Process data in 64-byte chunks */
      while (len >= 64) {
            memcpy (ctx->in, buf, 64);
            if (ctx->doByteReverse)
                  _byte_reverse (ctx->in, 16);
            md5_transform (ctx->buf, (guint32 *) 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)
 */
/**
 * md5_final: copy the final md5 hash to a bufer
 * @digest: 16 bytes buffer
 * @ctx: context containing the calculated md5
 * 
 * copy the final md5 hash to a bufer
 **/
void 
md5_final (MD5Context *ctx, unsigned char digest[16])
{
      guint32 count;
      unsigned char *p;
      
      /* Compute number of bytes mod 64 */
      count = (ctx->bits[0] >> 3) & 0x3F;
      
      /* Set the first char of padding to 0x80.  This is safe since there is
         always at least one byte free */
      p = ctx->in + count;
      *p++ = 0x80;
      
      /* Bytes of padding needed to make 64 bytes */
      count = 64 - 1 - count;
      
      /* Pad out to 56 mod 64 */
      if (count < 8) {
            /* Two lots of padding:  Pad the first block to 64 bytes */
            memset (p, 0, count);
            if (ctx->doByteReverse)
                  _byte_reverse (ctx->in, 16);
            md5_transform (ctx->buf, (guint32 *) ctx->in);
            
            /* Now fill the next block with 56 bytes */
            memset (ctx->in, 0, 56);
      } else {
            /* Pad block to 56 bytes */
            memset (p, 0, count - 8);
      }
      if (ctx->doByteReverse)
            _byte_reverse (ctx->in, 14);
      
      /* Append length in bits and transform */
      ((guint32 *) ctx->in)[14] = ctx->bits[0];
      ((guint32 *) ctx->in)[15] = ctx->bits[1];
      
      md5_transform (ctx->buf, (guint32 *) ctx->in);
      if (ctx->doByteReverse)
            _byte_reverse ((unsigned char *) ctx->buf, 4);
      memcpy (digest, ctx->buf, 16);
}


/* 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, data, s) \
      ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  md5_Update blocks
 * the data and converts bytes into longwords for this routine.
 */
static void 
md5_transform (guint32 buf[4], const guint32 in[16])
{
      register guint32 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;
}


/**
 * md5_get_digest: get the md5 hash of a buffer
 * @buffer: byte buffer
 * @buffer_size: buffer size (in bytes)
 * @digest: 16 bytes buffer receiving the hash code.
 * 
 * Get the md5 hash of a buffer. The result is put in 
 * the 16 bytes buffer @digest .
 **/
void
md5_get_digest (const char *buffer, unsigned int buffer_size, unsigned char digest[16])
{     
      MD5Context ctx;

      md5_init (&ctx);
      md5_update (&ctx, buffer, buffer_size);
      md5_final (&ctx, digest);
      
}


/**
 * md5_get_digest_from_file: get the md5 hash of a file
 * @filename: file name
 * @digest: 16 bytes buffer receiving the hash code.
 * 
 * Get the md5 hash of a file. The result is put in 
 * the 16 bytes buffer @digest .
 **/
void
md5_get_digest_from_file (const char *filename, unsigned char digest[16])
{     
      MD5Context ctx;
      unsigned char buf[1024];
      size_t nread;
      FILE *fp;
      
      d(fprintf (stderr, "generating checksum\n"));
      
      md5_init (&ctx);
      fp = fopen (filename, "rb");
      if (!fp)
            return;
      
      while ((nread = fread (buf, 1, 1024, fp)) > 0)
            md5_update (&ctx, buf, nread);
      
      if (ferror (fp)) {
            fclose (fp);
            return;
      }
      
      md5_final (&ctx, digest);
      
      fclose (fp);
      d(fprintf (stderr, "checksum done\n"));
}

Generated by  Doxygen 1.6.0   Back to index