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/apps/desktop/libvncserver/vncauth.c

http://ftk.googlecode.com/
C | 193 lines | 103 code | 42 blank | 48 comment | 17 complexity | 8369204dec772a4472310fbd2ed40e32 MD5 | raw file
  1/*
  2 *  Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
  3 *
  4 *  This is free software; you can redistribute it and/or modify
  5 *  it under the terms of the GNU General Public License as published by
  6 *  the Free Software Foundation; either version 2 of the License, or
  7 *  (at your option) any later version.
  8 *
  9 *  This software is distributed in the hope that it will be useful,
 10 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 *  GNU General Public License for more details.
 13 *
 14 *  You should have received a copy of the GNU General Public License
 15 *  along with this program; if not, write to the Free Software
 16 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 17 *  USA.
 18 */
 19
 20/*
 21 * vncauth.c - Functions for VNC password management and authentication.
 22 */
 23
 24#ifdef __STRICT_ANSI__
 25#define _BSD_SOURCE
 26#define _POSIX_SOURCE
 27#endif
 28#ifdef LIBVNCSERVER_HAVE_SYS_TYPES_H
 29#include <sys/types.h>
 30#endif
 31#include <stdio.h>
 32#include <stdlib.h>
 33#include <unistd.h>
 34#include <rfb/rfbproto.h>
 35#include "d3des.h"
 36
 37#include <string.h>
 38#include <math.h>
 39
 40#ifdef LIBVNCSERVER_HAVE_SYS_STAT_H
 41#include <sys/stat.h>
 42#endif
 43
 44#include <time.h>
 45
 46#ifdef WIN32
 47#define srandom srand
 48#define random rand
 49#else
 50#include <sys/time.h>
 51#endif
 52
 53
 54/* libvncclient does not need this */
 55#ifndef rfbEncryptBytes
 56
 57/*
 58 * We use a fixed key to store passwords, since we assume that our local
 59 * file system is secure but nonetheless don't want to store passwords
 60 * as plaintext.
 61 */
 62
 63static unsigned char fixedkey[8] = {23,82,107,6,35,78,88,7};
 64
 65
 66/*
 67 * Encrypt a password and store it in a file.  Returns 0 if successful,
 68 * 1 if the file could not be written.
 69 */
 70
 71int
 72rfbEncryptAndStorePasswd(char *passwd, char *fname)
 73{
 74    FILE *fp;
 75    unsigned int i;
 76    unsigned char encryptedPasswd[8];
 77
 78    if ((fp = fopen(fname,"w")) == NULL) return 1;
 79
 80	/* windows security sux */
 81#ifndef WIN32
 82    fchmod(fileno(fp), S_IRUSR|S_IWUSR);
 83#endif
 84
 85    /* pad password with nulls */
 86
 87    for (i = 0; i < 8; i++) {
 88	if (i < strlen(passwd)) {
 89	    encryptedPasswd[i] = passwd[i];
 90	} else {
 91	    encryptedPasswd[i] = 0;
 92	}
 93    }
 94
 95    /* Do encryption in-place - this way we overwrite our copy of the plaintext
 96       password */
 97
 98    rfbDesKey(fixedkey, EN0);
 99    rfbDes(encryptedPasswd, encryptedPasswd);
100
101    for (i = 0; i < 8; i++) {
102	putc(encryptedPasswd[i], fp);
103    }
104  
105    fclose(fp);
106    return 0;
107}
108
109
110/*
111 * Decrypt a password from a file.  Returns a pointer to a newly allocated
112 * string containing the password or a null pointer if the password could
113 * not be retrieved for some reason.
114 */
115
116char *
117rfbDecryptPasswdFromFile(char *fname)
118{
119    FILE *fp;
120    int i, ch;
121    unsigned char *passwd = (unsigned char *)malloc(9);
122
123    if ((fp = fopen(fname,"r")) == NULL) return NULL;
124
125    for (i = 0; i < 8; i++) {
126	ch = getc(fp);
127	if (ch == EOF) {
128	    fclose(fp);
129	    return NULL;
130	}
131	passwd[i] = ch;
132    }
133
134    fclose(fp);
135
136    rfbDesKey(fixedkey, DE1);
137    rfbDes(passwd, passwd);
138
139    passwd[8] = 0;
140
141    return (char *)passwd;
142}
143
144
145/*
146 * Generate CHALLENGESIZE random bytes for use in challenge-response
147 * authentication.
148 */
149
150void
151rfbRandomBytes(unsigned char *bytes)
152{
153    int i;
154    static rfbBool s_srandom_called = FALSE;
155
156    if (!s_srandom_called) {
157	srandom((unsigned int)time(NULL) ^ (unsigned int)getpid());
158	s_srandom_called = TRUE;
159    }
160
161    for (i = 0; i < CHALLENGESIZE; i++) {
162	bytes[i] = (unsigned char)(random() & 255);    
163    }
164}
165
166#endif
167
168/*
169 * Encrypt CHALLENGESIZE bytes in memory using a password.
170 */
171
172void
173rfbEncryptBytes(unsigned char *bytes, char *passwd)
174{
175    unsigned char key[8];
176    unsigned int i;
177
178    /* key is simply password padded with nulls */
179
180    for (i = 0; i < 8; i++) {
181	if (i < strlen(passwd)) {
182	    key[i] = passwd[i];
183	} else {
184	    key[i] = 0;
185	}
186    }
187
188    rfbDesKey(key, EN0);
189
190    for (i = 0; i < CHALLENGESIZE; i += 8) {
191	rfbDes(bytes+i, bytes+i);
192    }
193}