vncauth.c

破解vnc密码的程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "vncauth.h"
#include "d3des.h"


/*
 * We use a fixed key to store passwords, since we assume that our local
 * file system is secure but nonetheless don't want to store passwords
 * as plaintext.
 */

unsigned char fixedkey[8] = {23,82,107,6,35,78,88,7};


/*
 * Encrypt CHALLENGESIZE bytes in memory using a password.
 */

void
vncEncryptBytes(unsigned char *bytes, char *passwd)
{
    unsigned char key[8];
    unsigned int i;

    /* key is simply password padded with nulls */

    for (i = 0; i < 8; i++) {
        if (i < strlen(passwd)) {
            key[i] = passwd[i];
        } else {
            key[i] = 0;
        }
    }

    deskey(key, EN0);

    for (i = 0; i < CHALLENGESIZE; i += 8) {
                des(bytes+i, bytes+i);
    }
}


/*
 * Encrypt a password into the specified space.
 * encryptedPasswd will be 8 bytes long - sufficient space
 *   should be allocated.
 */

void
vncEncryptPasswd( unsigned char *encryptedPasswd, char *passwd )
{
        unsigned int i;

    /* pad password with nulls */
    for (i = 0; i < MAXPWLEN; i++) {
                if (i < strlen(passwd)) {
                        encryptedPasswd[i] = passwd[i];
                } else {
                        encryptedPasswd[i] = 0;
                }
    }

    /* Do encryption in-place - this way we overwrite our copy of the plaintext
       password */
    deskey(fixedkey, EN0);
    des(encryptedPasswd, encryptedPasswd);
}


/*
 * Decrypt a password.  Returns a pointer to a newly allocated
 * string containing the password or a null pointer if the password could
 * not be retrieved for some reason.
 */

char *
vncDecryptPasswd(const unsigned char *encryptedPasswd)
{
    unsigned int i;
    unsigned char *passwd = (unsigned char *)malloc(MAXPWLEN+1);

        memcpy(passwd, encryptedPasswd, MAXPWLEN);

    for (i = 0; i < MAXPWLEN; i++) {
                passwd[i] = encryptedPasswd[i];
    }

    deskey(fixedkey, DE1);
    des(passwd, passwd);

    passwd[MAXPWLEN] = 0;

    return (char *)passwd;
}