Bug 5898

Summary:

xorg starts then hangs on restart with fglrx

Product:

xorg

Reporter:

Jeremy C. Reed <reed>

Component:

App/xdm

Assignee:

Xorg Project Team <xorg-team>

Status:

RESOLVED FIXED

QA Contact:

Severity:

major

Priority:

high

Version:

7.0.0

Hardware:

x86 (IA32)

OS:

NetBSD

Whiteboard:

i915 platform:

i915 features:

Bug Depends on:

Bug Blocks:

5041

Attachments:

Description	Flags
Proposed fix to xdm modular tree	none

Description Jeremy C. Reed 2006-02-16 03:37:27 UTC

This is from NetBSD PR xsrc/32805
http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=32805

In Xsession: if for some reason $HOME/.xsession-errors is not used,
there is a race condition in the way the  "${TMPDIR-/tmp}/xses-$USER" or
"/tmp/xses-$USER" is created.

I emaield about this to xorg_security a couple days ago, but no response.

One idea is to create a subdirectory in /tmp (or $TMPDIR) (using umask 077 &&
mkdir) and then create file in it and then force a symlink from xses-$USER to
that file.

Or maybe use mktemp or similar if available.

Comment 1 Alan Coopersmith 2006-03-17 06:45:44 UTC

Created attachment 4969 [details] [review]
Proposed fix to xdm modular tree

A proposed fix based on the NetBSD fix - uses mktemp if available, but leaves
insecure code for systems without mktemp.   Assumes $HOME is safe to write to
without mktemp.

Comment 2 Jeremy C. Reed 2006-03-17 07:04:02 UTC

I didn't test this new patch, but I assume that all implementations of mktemp
create a file only readable by the user. Looks okay. I'd probably get rid of
that bad code anyways -- is it needed? If it reaches that part just fail with
some error message.

Or use umask && mkdir to make a temp directory, if that is successful create a
file in it and then move into place (and remove that temp directory).

Comment 3 Alan Coopersmith 2006-03-18 14:44:54 UTC

This feature (fallback to tmpdir when your home directory is unwritable) is 
little used enough and enough systems have a mktemp command that for now I'm 
just going to use mktemp and disable the alternate log paths on those without it.
Should someone care enough about making this work on a system without mktemp, 
a patch to do something like the mkdir solution suggested above will be happily
accepted in the future.

Fix checked into modular CVS head:
CVSROOT:	/cvs/xorg
Module name:	app
Changes by:	alanc@kemper.freedesktop.org	06/03/18 03:43:18

Log message:
  2006-03-17  Alan Coopersmith  <alan.coopersmith@sun.com>
  
  	* configure.ac:
  	* config/Xsession.cpp:
  	* config/Makefile.am:
  	Bug #5898 <https://bugs.freedesktop.org/show_bug.cgi?id=5898>
  	Use mktemp command to create files safely in TMPDIR or /tmp
  	on systems that have it - don't try to create files there if
  	mktemp is not present.   Fix based on NetBSD fix from
  	<http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=32805> .

Modified files:
      app/xdm/:
        ChangeLog configure.ac 
      app/xdm/config/:
        Makefile.am Xsession.cpp 
  
  Revision      Changes    Path
  1.36          +11 -0     app/xdm/ChangeLog
  http://cvs.freedesktop.org/xorg/app/xdm/ChangeLog
  1.35          +9 -2      app/xdm/configure.ac
  http://cvs.freedesktop.org/xorg/app/xdm/configure.ac
  1.9           +6 -2      app/xdm/config/Makefile.am
  http://cvs.freedesktop.org/xorg/app/xdm/config/Makefile.am
  1.4           +36 -8     app/xdm/config/Xsession.cpp
  http://cvs.freedesktop.org/xorg/app/xdm/config/Xsession.cpp

Marking this bug as fixed for the modular/7.x branch.   A clone will be needed
for the 6.9.x branch.

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