1 files changed, 161 insertions, 0 deletions
diff --git a/vncauth.c b/vncauth.c
new file mode 100644
index 0000000..69f38cf
--- /dev/null
+++ b/vncauth.c
@@ -0,0 +1,161 @@
+/*
+ *  Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ *  This is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This software is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ *  USA.
+ */
+
+/*
+ * vncauth.c - Functions for VNC password management and authentication.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "rfb.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 a password and store it in a file.  Returns 0 if successful,
+ * 1 if the file could not be written.
+ */
+
+int
+vncEncryptAndStorePasswd(char *passwd, char *fname)
+{
+    FILE *fp;
+    int i;
+    unsigned char encryptedPasswd[8];
+
+    if ((fp = fopen(fname,"w")) == NULL) return 1;
+
+    chmod(fname, S_IRUSR|S_IWUSR);
+
+    /* pad password with nulls */
+
+    for (i = 0; i < 8; 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);
+
+    for (i = 0; i < 8; i++) {
+	putc(encryptedPasswd[i], fp);
+    }
+  
+    fclose(fp);
+    return 0;
+}
+
+
+/*
+ * Decrypt a password from a file.  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 *
+vncDecryptPasswdFromFile(char *fname)
+{
+    FILE *fp;
+    int i, ch;
+    unsigned char *passwd = (unsigned char *)malloc(9);
+
+    if ((fp = fopen(fname,"r")) == NULL) return NULL;
+
+    for (i = 0; i < 8; i++) {
+	ch = getc(fp);
+	if (ch == EOF) {
+	    fclose(fp);
+	    return NULL;
+	}
+	passwd[i] = ch;
+    }
+
+    fclose(fp);
+
+    deskey(fixedkey, DE1);
+    des(passwd, passwd);
+
+    passwd[8] = 0;
+
+    return (char *)passwd;
+}
+
+
+/*
+ * Generate CHALLENGESIZE random bytes for use in challenge-response
+ * authentication.
+ */
+
+void
+vncRandomBytes(unsigned char *bytes)
+{
+    int i;
+    unsigned int seed = (unsigned int) time(0);
+
+    srandom(seed);
+    for (i = 0; i < CHALLENGESIZE; i++) {
+	bytes[i] = (unsigned char)(random() & 255);    
+    }
+}
+
+
+/*
+ * Encrypt CHALLENGESIZE bytes in memory using a password.
+ */
+
+void
+vncEncryptBytes(unsigned char *bytes, char *passwd)
+{
+    unsigned char key[8];
+    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);
+    }
+}