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162 lines
3.3 KiB
162 lines
3.3 KiB
/*
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* Copyright (C) 1999 AT&T Laboratories Cambridge. All Rights Reserved.
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This software is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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* USA.
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*/
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/*
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* vncauth.c - Functions for VNC password management and authentication.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <vncauth.h>
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#include <d3des.h>
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/*
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* We use a fixed key to store passwords, since we assume that our local
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* file system is secure but nonetheless don't want to store passwords
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* as plaintext.
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*/
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unsigned char fixedkey[8] = {23,82,107,6,35,78,88,7};
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/*
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* Encrypt a password and store it in a file. Returns 0 if successful,
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* 1 if the file could not be written.
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*/
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int
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vncEncryptAndStorePasswd(char *passwd, char *fname)
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{
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FILE *fp;
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int i;
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unsigned char encryptedPasswd[8];
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if ((fp = fopen(fname,"w")) == NULL) return 1;
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chmod(fname, S_IRUSR|S_IWUSR);
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/* pad password with nulls */
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for (i = 0; i < 8; i++) {
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if (i < strlen(passwd)) {
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encryptedPasswd[i] = passwd[i];
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} else {
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encryptedPasswd[i] = 0;
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}
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}
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/* Do encryption in-place - this way we overwrite our copy of the plaintext
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password */
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deskey(fixedkey, EN0);
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des(encryptedPasswd, encryptedPasswd);
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for (i = 0; i < 8; i++) {
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putc(encryptedPasswd[i], fp);
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}
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fclose(fp);
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return 0;
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}
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/*
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* Decrypt a password from a file. Returns a pointer to a newly allocated
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* string containing the password or a null pointer if the password could
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* not be retrieved for some reason.
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*/
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char *
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vncDecryptPasswdFromFile(char *fname)
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{
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FILE *fp;
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int i, ch;
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unsigned char *passwd = (unsigned char *)malloc(9);
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if ((fp = fopen(fname,"r")) == NULL) return NULL;
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for (i = 0; i < 8; i++) {
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ch = getc(fp);
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if (ch == EOF) {
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fclose(fp);
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return NULL;
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}
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passwd[i] = ch;
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}
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fclose(fp);
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deskey(fixedkey, DE1);
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des(passwd, passwd);
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passwd[8] = 0;
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return (char *)passwd;
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}
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/*
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* Generate CHALLENGESIZE random bytes for use in challenge-response
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* authentication.
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*/
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void
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vncRandomBytes(unsigned char *bytes)
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{
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int i;
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unsigned int seed = (unsigned int) time(0);
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srandom(seed);
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for (i = 0; i < CHALLENGESIZE; i++) {
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bytes[i] = (unsigned char)(random() & 255);
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}
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}
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/*
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* Encrypt CHALLENGESIZE bytes in memory using a password.
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*/
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void
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vncEncryptBytes(unsigned char *bytes, char *passwd)
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{
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unsigned char key[8];
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int i;
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/* key is simply password padded with nulls */
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for (i = 0; i < 8; i++) {
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if (i < strlen(passwd)) {
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key[i] = passwd[i];
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} else {
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key[i] = 0;
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}
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}
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deskey(key, EN0);
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for (i = 0; i < CHALLENGESIZE; i += 8) {
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des(bytes+i, bytes+i);
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}
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}
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