From 7f9ea27ec88dc0eaadc4cb6f9397f61a9fbad521 Mon Sep 17 00:00:00 2001
From: DRC <dcommander@users.sourceforge.net>
Date: Fri, 9 Jul 2010 19:37:14 +0000
Subject: [PATCH] Add a filter mode option to vncpasswd

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4085 3789f03b-4d11-0410-bbf8-ca57d06f2519
---
 unix/vncpasswd/vncpasswd.cxx | 19 ++++++++++++++++-
 unix/vncpasswd/vncpasswd.man | 40 +++++++++++++++++++++++++-----------
 2 files changed, 46 insertions(+), 13 deletions(-)

diff --git a/unix/vncpasswd/vncpasswd.cxx b/unix/vncpasswd/vncpasswd.cxx
index e8898792..a8f3afd0 100644
--- a/unix/vncpasswd/vncpasswd.cxx
+++ b/unix/vncpasswd/vncpasswd.cxx
@@ -1,4 +1,6 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright (C) 2010 Antoine Martin.  All Rights Reserved.
+ * Copyright (C) 2010 D. R. Commander.  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
@@ -33,7 +35,8 @@ char* prog;
 
 static void usage()
 {
-  fprintf(stderr,"usage: %s [file]\n",prog);
+  fprintf(stderr,"usage: %s [file]\n", prog);
+  fprintf(stderr,"       %s -f\n", prog);
   exit(1);
 }
 
@@ -63,6 +66,18 @@ static char* getpassword(const char* prompt) {
   return 0;
 }
 
+// Reads password from stdin and prints encrypted password to stdout.
+static int encrypt_pipe() {
+  PlainPasswd buf(256);
+  fgets(buf.buf, 256, stdin);
+  ObfuscatedPasswd obfuscated(buf);
+  //fputs(prompt, stdout);
+  if (fwrite(obfuscated.buf, obfuscated.length, 1, stdout) != 1) {
+    fprintf(stderr,"Writing to stdout failed\n");
+    return 1;
+  }
+  return 0;
+}
 
 int main(int argc, char** argv)
 {
@@ -72,6 +87,8 @@ int main(int argc, char** argv)
 
   for (int i = 1; i < argc; i++) {
     if (strcmp(argv[i], "-q") == 0) { // allowed for backwards compatibility
+    } else if (strncmp(argv[i], "-f", 2) == 0) {
+      return encrypt_pipe();
     } else if (argv[i][0] == '-') {
       usage();
     } else if (!fname) {
diff --git a/unix/vncpasswd/vncpasswd.man b/unix/vncpasswd/vncpasswd.man
index c846d576..27c04fe2 100644
--- a/unix/vncpasswd/vncpasswd.man
+++ b/unix/vncpasswd/vncpasswd.man
@@ -1,26 +1,38 @@
-.TH vncpasswd 1 "05 May 2006" "TigerVNC" "Virtual Network Computing"
+.TH vncpasswd 1 "09 Jul 2010" "TigerVNC" "Virtual Network Computing"
 .SH NAME
-vncpasswd \- change a VNC password
+vncpasswd \- change the VNC password
 .SH SYNOPSIS
-.B vncpasswd
-.RI [ passwd-file ]
+\fBvncpasswd\fR [\fIpasswd-file\fR]
+.br
+\fBvncpasswd\fR \-f
 .SH DESCRIPTION
 .B vncpasswd
-allows you to set the password used to access VNC desktops.  It stores an
-obfuscated version of the password in the given file (default
-$HOME/.vnc/passwd).  The \fBvncserver\fP script runs \fBvncpasswd\fP the first
-time you start a VNC desktop, and invokes \fBXvnc\fP with the appropriate
+allows you to set the password used to access VNC desktops.  Its default
+behavior is to prompt for a VNC password and then store an obfuscated version
+of this password to \fIpasswd-file\fR (or to $HOME/.vnc/passwd if no password
+file is specified.)  The \fBvncserver\fP script runs \fBvncpasswd\fP the first
+time you start a VNC desktop, and it invokes \fBXvnc\fP with the appropriate
 \fB\-rfbauth\fP option.  \fBvncviewer\fP can also be given a password file to
 use via the \fB\-passwd\fP option.
 
-The password must be at least six characters long, and only the first eight
+The password must be at least six characters long (unless the \fB\-f\fR
+command-line option is used-- see below), and only the first eight
 characters are significant.  Note that the stored password is \fBnot\fP
 encrypted securely - anyone who has access to this file can trivially find out
-the plaintext password, so \fBvncpasswd\fP always sets appropriate permissions
-(read and write only by the owner).  However, when accessing a VNC desktop a
+the plain-text password, so \fBvncpasswd\fP always sets appropriate permissions
+(read and write only by the owner.)  However, when accessing a VNC desktop, a
 challenge-response mechanism is used over the wire making it hard for anyone to
 crack the password simply by snooping on the network.
 
+.SH OPTIONS
+
+.TP
+.B \-f
+Filter mode.  Read a plain-text password from stdin and write an encrypted
+version to stdout.  Note that in filter mode, short or even empty passwords
+will be silently accepted.
+
+
 .SH FILES
 .TP
 $HOME/.vnc/passwd
@@ -34,8 +46,12 @@ Default location of the VNC password file.
 .br
 http://www.tigervnc.org
 
-.SH AUTHOR
+.SH AUTHORS
 Tristan Richardson, RealVNC Ltd.
+.br
+Antoine Martin
+.br
+D. R. Commander
 
 VNC was originally developed by the RealVNC team while at Olivetti
 Research Ltd / AT&T Laboratories Cambridge.  TightVNC additions were
-- 
2.39.5