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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef __MSDOS__
#include <dos.h>
#endif
#ifdef unix /* Assume POSIX */
#include <fcntl.h>
#include <termios.h>
#endif
#include "md4.h"
#include "skey.h"
#if (defined(__MSDOS__) || defined(MPU8086) || defined(MPU8080) \
|| defined(vax) || defined (MIPSEL))
#define LITTLE_ENDIAN /* Low order bytes are first in memory */
#endif /* Almost all other machines are big-endian */
/* Crunch a key:
* concatenate the seed and the password, run through MD4 and
* collapse to 64 bits. This is defined as the user's starting key.
*/
int
keycrunch(result,seed,passwd)
char *result; /* 8-byte result */
char *seed; /* Seed, any length */
char *passwd; /* Password, any length */
{
char *buf;
MDstruct md;
unsigned int buflen;
#ifndef LITTLE_ENDIAN
int i;
register long tmp;
#endif
buflen = strlen(seed) + strlen(passwd);
if((buf = malloc(buflen+1)) == NULL)
return -1;
strcpy(buf,seed);
strcat(buf,passwd);
/* Crunch the key through MD4 */
sevenbit(buf);
MDbegin(&md);
MDupdate(&md,(unsigned char *)buf,8*buflen);
free(buf);
/* Fold result from 128 to 64 bits */
md.buffer[0] ^= md.buffer[2];
md.buffer[1] ^= md.buffer[3];
#ifdef LITTLE_ENDIAN
/* Only works on byte-addressed little-endian machines!! */
memcpy(result,(char *)md.buffer,8);
#else
/* Default (but slow) code that will convert to
* little-endian byte ordering on any machine
*/
for(i=0;i<2;i++){
tmp = md.buffer[i];
*result++ = tmp;
tmp >>= 8;
*result++ = tmp;
tmp >>= 8;
*result++ = tmp;
tmp >>= 8;
*result++ = tmp;
}
#endif
return 0;
}
/* The one-way function f(). Takes 8 bytes and returns 8 bytes in place */
void
f(x)
char *x;
{
MDstruct md;
#ifndef LITTLE_ENDIAN
register long tmp;
#endif
MDbegin(&md);
MDupdate(&md,(unsigned char *)x,64);
/* Fold 128 to 64 bits */
md.buffer[0] ^= md.buffer[2];
md.buffer[1] ^= md.buffer[3];
#ifdef LITTLE_ENDIAN
/* Only works on byte-addressed little-endian machines!! */
memcpy(x,(char *)md.buffer,8);
#else
/* Default (but slow) code that will convert to
* little-endian byte ordering on any machine
*/
tmp = md.buffer[0];
*x++ = tmp;
tmp >>= 8;
*x++ = tmp;
tmp >>= 8;
*x++ = tmp;
tmp >>= 8;
*x++ = tmp;
tmp = md.buffer[1];
*x++ = tmp;
tmp >>= 8;
*x++ = tmp;
tmp >>= 8;
*x++ = tmp;
tmp >>= 8;
*x = tmp;
#endif
}
/* Strip trailing cr/lf from a line of text */
void
rip(buf)
char *buf;
{
char *cp;
if((cp = strchr(buf,'\r')) != NULL)
*cp = '\0';
if((cp = strchr(buf,'\n')) != NULL)
*cp = '\0';
}
/************************/
#ifdef __MSDOS__
char *
readpass(buf,n)
char *buf;
int n;
{
int i;
char *cp;
for(cp=buf,i = 0; i < n ; i++)
if ((*cp++ = bdos(7,0,0)) == '\r')
break;
*cp = '\0';
printf("\n");
rip(buf);
return buf;
}
#else
char *
readpass(buf,n)
char *buf;
int n;
{
struct termios saved_ttymode;
struct termios noecho_ttymode;
/* Save normal line editing modes */
tcgetattr(0, &saved_ttymode);
/* Turn off echoing */
tcgetattr(0, &noecho_ttymode);
noecho_ttymode.c_lflag &= ~ECHO;
tcsetattr(0, TCSANOW, &noecho_ttymode);
fgets(buf,n,stdin);
rip(buf);
/* Restore previous tty modes */
tcsetattr(0, TCSANOW, &saved_ttymode);
/*
after the secret key is taken from the keyboard, the line feed is
written to standard error instead of standard output. That means that
anyone using the program from a terminal won't notice, but capturing
standard output will get the key words without a newline in front of
them.
*/
fprintf(stderr, "\n");
fflush(stderr);
sevenbit(buf);
return buf;
}
#endif
/* removebackspaced over charaters from the string*/
backspace(buf)
char *buf;
{
char bs = 0x8;
char *cp = buf;
char *out = buf;
while(*cp){
if( *cp == bs ) {
if(out == buf){
cp++;
continue;
}
else {
cp++;
out--;
}
}
else {
*out++ = *cp++;
}
}
*out = '\0';
}
sevenbit(s)
char *s;
{
/* make sure there are only 7 bit code in the line*/
while(*s){
*s = 0x7f & ( *s);
s++;
}
}
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