Scientific Linux Security Update : gfs-kmod on SL 5.0-5.4 i386/x86_64

This script is Copyright (C) 2012 Tenable Network Security, Inc.


Synopsis :

The remote Scientific Linux host is missing one or more security
updates.

Description :

This updated gfs-kmod is already in SL 5.5.

A flaw was found in the gfs_lock() implementation. The GFS locking
code could skip the lock operation for files that have the S_ISGID bit
(set-group-ID on execution) in their mode set. A local, unprivileged
user on a system that has a GFS file system mounted could use this
flaw to cause a kernel panic. (CVE-2010-0727)

These updated gfs-kmod packages are in sync with the latest kernel
(2.6.18-194.el5). The modules in earlier gfs-kmod packages failed to
load because they did not match the running kernel. It was possible to
force-load the modules. With this update, however, users no longer
need to.

These updated gfs-kmod packages also fix the following bugs :

- when SELinux was in permissive mode, a race condition
during file creation could have caused one or more
cluster nodes to be fenced and lock the remaining nodes
out of the GFS file system. This race condition no
longer occurs with this update. (BZ#471258)

- when ACLs (Access Control Lists) are enabled on a GFS
file system, if a transaction that has started to do a
write request does not have enough spare blocks for the
operation it causes a kernel panic. This update ensures
that there are enough blocks for the write request
before starting the operation. (BZ#513885)

- requesting a 'flock' on a file in GFS in either
read-only or read-write mode would sometimes cause a
'Resource temporarily unavailable' state error (error 11
for EWOULDBLOCK) to occur. In these cases, a flock could
not be obtained on the file in question. This has been
fixed with this update so that flocks can successfully
be obtained on GFS files without this error occurring.
(BZ#515717)

- the GFS withdraw function is a data integrity feature of
GFS file systems in a cluster. If the GFS kernel module
detects an inconsistency in a GFS file system following
an I/O operation, the file system becomes unavailable to
the cluster. The GFS withdraw function is less severe
than a kernel panic, which would cause another node to
fence the node. With this update, you can override the
GFS withdraw function by mounting the file system with
the '-o errors=panic' option specified. When this option
is specified, any errors that would normally cause the
system to withdraw cause the system to panic instead.
This stops the node's cluster communications, which
causes the node to be fenced. (BZ#517145)

Finally, these updated gfs-kmod packages provide the following
enhancement :

- the GFS kernel modules have been updated to use the new
generic freeze and unfreeze ioctl interface that is also
supported by the following file systems: ext3, ext4,
GFS2, JFS and ReiserFS. With this update, GFS supports
freeze/unfreeze through the VFS-level FIFREEZE/FITHAW
ioctl interface. (BZ#487610)

See also :

http://www.nessus.org/u?48fead04
https://bugzilla.redhat.com/show_bug.cgi?id=471258
https://bugzilla.redhat.com/show_bug.cgi?id=487610
https://bugzilla.redhat.com/show_bug.cgi?id=513885
https://bugzilla.redhat.com/show_bug.cgi?id=515717
https://bugzilla.redhat.com/show_bug.cgi?id=517145

Solution :

Update the affected kmod-gfs, kmod-gfs-PAE and / or kmod-gfs-xen
packages.

Risk factor :

Medium / CVSS Base Score : 4.7
(CVSS2#AV:L/AC:M/Au:N/C:N/I:N/A:C)

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 60768 ()

Bugtraq ID:

CVE ID: CVE-2010-0727