Date: Sat, 19 Mar 2011 11:09:28 +1100 (EST) From: Peter Jeremy <peterjeremy@acm.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: ports/155683: x11/xdm [patch] Enabling IPv6 support breaks IPv4 Message-ID: <201103190009.p2J09SVi004462@server.vk2pj.dyndns.org> Resent-Message-ID: <201103190010.p2J0AAU0033565@freefall.freebsd.org>
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>Number: 155683
>Category: ports
>Synopsis: x11/xdm [patch] Enabling IPv6 support breaks IPv4
>Confidential: no
>Severity: serious
>Priority: low
>Responsible: freebsd-ports-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat Mar 19 00:10:10 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Peter Jeremy
>Release: FreeBSD 8.2-STABLE amd64
>Organization:
n/a
>Environment:
System: FreeBSD server.vk2pj.dyndns.org 8.2-STABLE FreeBSD 8.2-STABLE #9: Sun Feb 27 17:46:10 EST 2011 root@server.vk2pj.dyndns.org:/var/obj/usr/src/sys/server amd64
xdm-1.1.8_3
>Description:
If the xdm configure script detects IPv6 support is available,
it will build a version of xdm that supports xdmcp over IPv6.
Unfortunately, due to a long outstanding bug (google shows
references back to 2006), xdm then no longer supports IPv4.
>How-To-Repeat:
Given two hosts A and B, both running a "generic" world (ie no
"WITHOUT_INET6" or similar) with xorg and having only IPv4
addresses on physical networks:
On host A, comment out the line "DisplayManager.requestPort: 0" in
in /usr/local/lib/X11/xdm/xdm-config, add B's FQDN to
/usr/local/lib/X11/xdm/Xaccess and [re]start xdm. Use
lsof or similar to show that xdm is listening on UDP6:177
On host B, start X with the options '-nolisten inet6 -query A'.
Use tcpdump or similar to show that X on host B is sending
xdmcp packets to UDP:177 on host A and receiving ICMP port
unreachable packets back.
>Fix:
The correct fix is to change xdm to simultaneously handle both
IPv4 and IPv6 xdmcp requests. I haven't been able to find
suitable code on the net.
As a work-around, I suggest the following patch to the port
Makefile to make IPv6 optional (defaulting to off).
Index: Makefile
===================================================================
RCS file: /usr/ncvs/ports/x11/xdm/Makefile,v
retrieving revision 1.10
diff -u -r1.10 Makefile
--- Makefile 25 Feb 2011 16:52:19 -0000 1.10
+++ Makefile 18 Mar 2011 23:37:48 -0000
@@ -18,6 +18,14 @@
CONFIGURE_ARGS+= --with-xdmconfigdir=${EXAMPLESDIR} \
--with-xdmscriptdir=${EXAMPLESDIR}
+OPTIONS= IPV6 "Enable IPv6 support (breaks IPv4)." Off
+
+.include <bsd.port.options.mk>
+
+.if defined(WITHOUT_IPV6)
+CONFIGURE_ARGS+= --disable-ipv6
+.endif
+
MAN1= xdm.1
CFFILES= GiveConsole TakeConsole Xaccess Xreset Xresources \
>Release-Note:
>Audit-Trail:
>Unformatted:
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