CVE-2008-3832 kernel: null pointer dereference in utrace_control

[Eugene Teo <eteo () redhat com>]

Michael Simms reported that it is possible for an unprivileged user to
crash the machine by running gdb on a running process with pid 1.

This affects the version of utrace as shipped with Fedora 8 and 9. This
is addressed in kernel-2.6.26.5-28 for Fedora 8, and kernel-2.6.26.5-45
for Fedora 9. This issue is specific to Fedora, and does not affect
upstream or any of the Red Hat Enterprise Linux kernels.

References:
http://kerneloops.org/oops.php?number=56705
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2008-3832

Thanks, Eugene
-- 
Eugene Teo / Red Hat Security Response Team

Index: linux-2.6-utrace.patch
===================================================================
RCS file: /cvs/pkgs/rpms/kernel/F-9/linux-2.6-utrace.patch,v
retrieving revision 1.78
retrieving revision 1.79
diff -u -b -p -r1.78 -r1.79
--- linux-2.6-utrace.patch      4 Aug 2008 22:20:04 -0000       1.78
+++ linux-2.6-utrace.patch      15 Sep 2008 23:50:37 -0000      1.79
@@ -1994,7 +1994,7 @@ index ef66127..dcf30f5 100644  
 +      if (IS_ERR(engine))
 +              return engine;
 +      if (likely(!ptrace_update_utrace(child, engine)))
-+              return 0;
++              return engine;
 +      ptrace_detach_utrace(child, engine);
 +      return ERR_PTR(-ESRCH);
 +}