SuSE Linux Advisory: kernel

SuSE Security Announcement

Content of this advisory:

1. security vulnerability resolved: a race condition in the ELF
   loader, a minor information leakage problem in the proc-fs,
   re-binding problem of UDP port 2049 sockets, DoS in netfilter and
   NFSv3 code
2. pending vulnerabilities, solutions, workarounds:
   • xfstt
   • heartbeat
   • KDE config files
   • several minor bug fixes
3. standard appendix (further information)

1) problem description, brief discussion, solution, upgrade
information

During the last weeks a couple of security relevant fixes have
been accumulated for the kernel. These fix local vulnerabilities
and remote DoS conditions. The list of the fixed vulnerabilities is
as follows:

• fix for a possible denial of service attack (DoS) in the
  routing code
• fix for a possible attack of an unpriviledged user via
  ioport
• fix for a re-binding problem of UDP port 2049 (NFS)
  sockets
• fix for a kernel panic with pptpd when mss > mtu
• fix for console redirect bug
• fix for the execve() file read race vulnerability
• fix for several race conditions in procfs
• fix for possible DoS in netfilter code
• fix for possible DoS in NFSv3 code

Not all kernel-versions are affected by all of these
vulnerabilities. However, since there is no easy workaround for all
of the vulnerabilities, we recommend an update of the kernel
package.

Please follow the steps in the “SPECIAL INSTALL INSTRUCTIONS”
section to update your system.

Note: Managing the necessary patches, building and mostly
testing kernel update packages is an extremely worksome and
therefore also time-consuming process. SuSE wishes to provide the
same quality and reliability in update packages as customers are
used to from the shipped original products. Even though our kernel
updates are thoroughly tested, the numerous possible hardware
configurations for the x86 platform give a certain probability for
a functional failure of parts of the kernel after the update has
been performed. Some of the possible failures cannot be handled by
SuSE by definition. These include (and are not limited to) possible
problems with NVIDIA chipset graphics boards that make use of
hardware 3D acceleration. SuSE cannot deliver the binary only
driver for the NVIDIA graphics boards in the kernel RPM. It is
known that the NVIDIA hardware acceleration will not continue to
work after a reboot, resulting in a failure to start the X-server.
Hardware acceleration support for NVIDIA graphics chipsets on SuSE
Linux 8.1 and 8.2 will be automatically disabled if the kernel
update is performed by YOU (Yast Online Update). If you are
committing the update by hand (necessary for SuSE Linux 8.0 and
older), you should either turn off hardware acceleration support
for your X Server configuration, or you may want to link the
acceleration driver with binaries directly from nvidia’s ftp server
yourself, using the provided kernel-source RPM package.

The kernel of a Linux system is the most critical component with
respect to stability, reliability and security. By consequence, an
update of that component requires some care and full attention to
succeed.

SPECIAL INSTALL INSTRUCTIONS:

The following paragraphs will guide you through the installation
process in a step-by-step fashion. The character sequence “****”
marks the beginning of a new paragraph. In some cases, you decide
if the paragraph is needed for you or not. Please read through all
of the steps down to the end. All of the commands that need to be
executed are required to be run as the superuser (root). Each step
relies on the steps before to complete successfully.

Step 1: Determine the needed kernel type

Please use the following command to find the kernel type that is
installed on your system:

rpm -qf /boot/vmlinuz

The following options are possible (disregarding the version and
build number following the name, separated by the “-”
character):

Step 2: Download the package for your system

Please download the kernel RPM package for your distribution
with the name starting as indicated by Step 1. The list of all
kernel rpm packages is appended below. Note: The kernel-source
package does not contain any binary kernel in bootable form.
Instead, it contains the sources that the binary kernel rpm
packages are made from. It can be used by administrators who have
decided to build their own kernel. Since the kernel-source.rpm is
an installable (compiled) package that contains sources for the
linux kernel, it is not the source RPM for the kernel RPM binary
packages.

The kernel RPM binary packages for the distributions can be
found at these locations under ftp://ftp.suse.com/pub/suse/i386/update/
:

7.2/kernel/2.4.18-20030812
7.3/kernel/2.4.18-20030812
8.0/kernel/2.4.18-20030812
8.1/rpm/i586
8.2/rpm/i586

After downloading the kernel RPM package for your system, you
should verify the authenticity of the kernel rpm package using the
methods as listed in section 3) of each SuSE Security
Announcement.

Step 3: Installing your kernel rpm package

Install the rpm package that you have downloaded in Steps 3 or 4
with the command

rpm -Uhv –nodeps –force <K_FILE.RPM> where
<K_FILE.RPM> is the name of the rpm package that you
downloaded.

Warning: After performing this step, your system will
likely not be able to boot if the following steps have not been
fully applied.

If you run SuSE Linux 8.1 and use the freeswan package, you also
need to update the freeswan rpm as a dependency as offered by YOU
(Yast Online Update). The package can be downloaded from ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/

Step 4: configuring and creating the initrd

The initrd is a ramdisk that is being loaded into the memory of
your system together with the kernel boot image by the bootloader.
The kernel uses the content of this ramdisk to execute commands
that must be run before the kernel can mount its actual root
filesystem. It is usually used to initialize scsi drivers or NIC
drivers for diskless operation.

The variable INITRD_MODULES (set in the files /etc/rc.config up
to 7.3) or /etc/sysconfig/kernel (after and including 8.0))
determines which kernel modules will be loaded in the initrd before
the kernel has mounted its actual root filesystem. The variable
should contain your scsi adapter (if any) or filesystem driver
modules.

With the installation of the new kernel, the initrd has to be
re-packed with the update kernel modules. Please run the
command

mk_initrd

as root to create a new init rmadisk (initrd) for your
system.

Step 5: bootloader

If you have a 7.x system, you must now run the command

lilo

as root to initialize the lilo bootloader for your system. Then
proceed to the next step.

If you run a SuSE Linux 8.x or a SLES8 system, there are two
options: Depending on your software configuration, you have the
lilo bootloader or the grub bootloader installed and initialized on
your system. The grub bootloader does not require any further
actions to be performed after the new kernel images have been moved
in place by the rpm Update command.
If you have a lilo bootloader installed and initialized, then the
lilo program must be run as root. Use the command

grep LOADER_TYPE /etc/sysconfig/bootloader

to find out which boot loader is configured. If it is lilo, then
you must run the lilo command as root. If grub is listed, then your
system does not require any bootloader initialization.

Warning: An improperly installed bootloader may render
your system unbootable.

Step 6: reboot

If all of the steps above have been successfully applied to your
system, then the new kernel including the kernel modules and the
initrd should be ready to boot. The system needs to be rebooted for
the changes to become active. Please make sure that all steps are
complete, then reboot using the command

shutdown -r now
or

init 6

Your system should now shut down and reboot with the new
kernel.

Download sources for all kernel RPM packages: Our maintenance
customers are being notified individually. The packages are being
offered to install from the maintenance web.

Due to the large amount of package-names you will not find the
usual list of package-names with the corresponding MD5 sums here.
However the integrity of the packages is ensured and can be
verified as described in section 3.2.

2) Pending vulnerabilities in SuSE Distributions and
Workarounds:

• xfstt The X truetype font-server can be crashed my sending
  malicious packets over the network. It may even be possible to
  execute arbitrary commands with the privileges of the xfstt server.
  Update packages are available on our FTP servers now.
• heartbeat New heartbeat packages which fix an overflow are
  available on our ftp servers.
• KDE config files Due to an mistake some files in
  /etc/opt/kde3/share/config/ of SuSe Linux 8.2 are world-writeable.
  Under certain circumstances these files can be used to gain higher
  privileges. Please add an entry for each file in your
  /etc/permissions.local file. Example:
  /etc/opt/kde3/share/config/kmailrc root.root 0644

This bug was reported by nordi <[email protected]>.

• several minor bug fixes There are alot more minor security
  updates in the queue. YOU (Yast Online Update) will inform you when
  they appear. Alternatively you may want to monitor the following
  website:
  http://www.suse.de/de/private/download/updates/index.html

  or: http://www.suse.de/en/private/download/updates/index.html

3) standard appendix: authenticity verification, additional
information

Package authenticity verification:

SuSE update packages are available on many mirror ftp servers
all over the world. While this service is being considered valuable
and important to the free and open source software community, many
users wish to be sure about the origin of the package and its
content before installing the package. There are two verification
methods that can be used independently from each other to prove the
authenticity of a downloaded file or rpm package:

1. md5sums as provided in the (cryptographically signed)
   announcement.
2. using the internal gpg signatures of the rpm package.
3. execute the command
   md5sum <name-of-the-file.rpm>
   after you downloaded the file from a SuSE ftp server or its
   mirrors. Then, compare the resulting md5sum with the one that is
   listed in the announcement. Since the announcement containing the
   checksums is cryptographically signed (usually using the key
   [email protected]), the
   checksums show proof of the authenticity of the package. We
   disrecommend to subscribe to security lists which cause the email
   message containing the announcement to be modified so that the
   signature does not match after transport through the mailing list
   software.
   Downsides: You must be able to verify the authenticity of the
   announcement in the first place. If RPM packages are being rebuilt
   and a new version of a package is published on the ftp server, all
   md5 sums for the files are useless.
4. rpm package signatures provide an easy way to verify the
   authenticity of an rpm package. Use the command rpm -v –checksig
   <file.rpm> to verify the signature of the package, where
   <file.rpm> is the filename of the rpm package that you have
   downloaded. Of course, package authenticity verification can only
   target an un-installed rpm package file. Prerequisites:
   1. gpg is installed
   2. The package is signed using a certain key. The public part of
      this key must be installed by the gpg program in the directory
      ~/.gnupg/ under the user’s home directory who performs the
      signature verification (usually root). You can import the key that
      is used by SuSE in rpm packages for SuSE Linux by saving this
      announcement to a file (“announcement.txt”) and running the command
      (do “su -” to be root): gpg –batch; gpg < announcement.txt |
      gpg –import SuSE Linux distributions version 7.1 and thereafter
      install the key “[email protected]”
      upon installation or upgrade, provided that the package gpg is
      installed. The file containing the public key is placed at the
      top-level directory of the first CD (pubring.gpg) and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de
      .

• SuSE runs two security mailing lists to which any interested
  party may subscribe:

[email protected]

• general/linux/SuSE security discussion.
  All SuSE security announcements are sent to this list. To
  subscribe, send an email to
  <[email protected]>.

[email protected]

• SuSE’s announce-only mailing list.
  Only SuSE’s security announcements are sent to this list. To
  subscribe, send an email to
  <[email protected]>.

For general information or the frequently asked questions (faq)
send mail to:

<[email protected]>
or
<[email protected]>
respectively.

SuSE’s security contact is <[email protected]> or
<[email protected]>. The
<[email protected]>
public key is listed below.

The information in this advisory may be distributed or
reproduced, provided that the advisory is not modified in any way.
In particular, it is desired that the clear-text signature shows
proof of the authenticity of the text.
SuSE Linux AG makes no warranties of any kind whatsoever with
respect to the information contained in this security advisory.