Bug 83683 – net-irc/xchat 2.4.1 & dccserver leaves listening tcp ports open after having started a subprocess

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Stefan Becker 2005-03-01 07:04:25 UTC]

My xchat is built with the xchatdccserver-flag and I can use the /dccserver-command to open listening ports for incoming file-transfers. Now if I start any subprocess like "Run new Mozilla" or simply "/exec bash" and close or change the dccserver port, netstat shows the subprocess as the owner of that port and the port is blocked until the process is killed.
- I dont know if it's a security issue but I think ports should never be open for no reason. I was a bit puzzled when I saw that the first time.

Reproducible: Always
Steps to Reproduce:
1. xchat: /DCCSERVER + 6666
2. xchat: /exec bash
--> netstat: tcp        0      0 0.0.0.0:6666            0.0.0.0:*               LISTEN      10030/xchat-2
3. xchat: /DCCSERVER -
--> netstat: tcp        0      0 0.0.0.0:6666            0.0.0.0:*               LISTEN      23524/bash
Actual Results:  
listening port still open and blocked for any other process

Expected Results:  
listening port closed

emerge info:
Portage 2.0.51-r15 (default-linux/x86/2004.3, gcc-3.4.3,
glibc-2.3.4.20040808-r1, 2.6.10-gentoo-r6-2 i686)
=================================================================
System uname: 2.6.10-gentoo-r6-2 i686 Pentium III (Katmai)
Gentoo Base System version 1.4.16
Python:              dev-lang/python-2.3.4-r1 [2.3.4 (#1, Feb  8 2005, 12:06:00)]
dev-lang/python:     2.3.4-r1
sys-devel/autoconf:  2.59-r6, 2.13
sys-devel/automake:  1.7.9-r1, 1.8.5-r3, 1.5, 1.4_p6, 1.6.3, 1.9.4
sys-devel/binutils:  2.15.92.0.2-r1
sys-devel/libtool:   1.5.10-r4
virtual/os-headers:  2.6.8.1-r2
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CFLAGS="-O2 -march=pentium3 -fomit-frame-pointer -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3/share/config
/usr/lib/X11/xkb /usr/lib/mozilla/defaults/pref /usr/share/config
/usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/
/usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/
/usr/share/texmf/xdvi/ /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS="-O2 -march=pentium3 -fomit-frame-pointer -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoaddcvs autoconfig ccache distlocks sandbox sfperms"
GENTOO_MIRRORS="http://ftp.easynet.nl/mirror/gentoo/
http://ftp.du.se/pub/os/gentoo
http://www.die.unipd.it/pub/Linux/distributions/gentoo-sources/"
LANG="de_DE@euro"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="x86 X acpi apache2 apm avi berkdb bigger-fonts bindist bitmap-fonts bonobo
cdr crypt cups dga directfb divx4linux dv dvb dvd emboss encode esd ethereal f77
fam fbcon flac font-server foomaticdb fortran gcj gdbm gif gimpprint gnome
gnutls gphoto2 gstreamer gtk gtk2 guile idea imagemagick imlib java jpeg ldap
libg++ libwww lirc live mad maildir matroska mikmod mmap mmx mng mozilla
moznocompose moznoirc mozsvg mpeg mule mysql ncurses network nls nocardbus nopri
nozaptel nvidia offensive ogg oggvorbis opengl oss pam pdflib perl plotutils png
ppds prelude python quicktime readline real scanner sdl slang speex spell sse
ssl svg tcpd tetex theora tiff truetype truetype-fonts type1-fonts unicode usb
v4l v4l2 videos wmf xchatdccserver xml xml2 xmms xv xvid zlib"
Unset:  ASFLAGS, CBUILD, CTARGET, LC_ALL, LDFLAGS

[Comment 1 foser (RETIRED) 2005-03-01 07:18:30 UTC]

afaik xchat dcc server is more a proof of concept and should be used with care, i wonder who ever introduced a USE flag for this ?

[Comment 2 Sven Wegener 2005-03-01 08:49:10 UTC]

I added it wrt bug #54509. It's experimental, but official support has been
added to the 2.4.1b windows version, so I expect official support for Linux
or other supported OSes in the next version.

Concerning this bug, I'll look at the patch and modify it to close the DCC
server port on /exec and pass the modified patch upstream.

[Comment 3 Stefan Becker 2005-03-01 09:46:13 UTC]

I'm not sure if official support will be included in the Linux version soon. The source for dccserver is not in xchat's cvs and with wanting money for the windows version the author might not do it ever.

As for the bug, just to make clear: it also happens when the built-in xchat-commands open a browser from an url (or gftp or probably anything). I don't know if it just uses the '/exec' command internally.

[Comment 4 Sven Wegener 2005-03-01 12:15:12 UTC]

While modifying the dccserver patch I noticed that xchat exposes all open sockets
and files to it's child. I'll patch it and send it to xchat's author.

firefox 22557 sven    5w   REG      253,3    28374    31384 /home/sven/.xchat2/xchatlogs/QuakeNet-quakenet.log
firefox 22557 sven    7u  IPv4     756730               TCP luna.wegener.lan.stealer.net:20243->sw.de.quakenet.org:ircd (ESTABLISHED)

[Comment 5 Sven Wegener 2005-03-01 12:57:18 UTC]

Patch sent to zed.

[Comment 6 Sven Wegener 2005-03-04 14:29:26 UTC]

Patch has been commited to the xchat CVS repository. I've included the patch in
our ebuild and bump the revision to -r1.