SUSE Linux Advisory: kernel
Oct 22, 2004, 15:57 (3 Talkback[s])
SUSE Security Announcement
Date: Wednesday, Oct 20th 2004 18:00 MEST
Affected products: 9.1 SUSE Linux Enterprise Server 9
Vulnerability Type: remote denial of service
Severity (1-10): 9
SUSE default package: yes
Cross References: CAN-2004-0816 CAN-2004-0887
Content of this advisory:
- security vulnerability resolved:
- remote system crash with enabled firewall
- local root exploit on the S/390 platform
- minor /proc information leaks problem description
- special instructions and notes
- package location and checksums
- pending vulnerabilities, solutions, workarounds:
1) problem description, brief discussion
An integer underflow problem in the iptables firewall logging
rules can allow a remote attacker to crash the machine by using a
handcrafted IP packet. This attack is only possible with
We would like to thank Richard Hart for reporting the
This problem has already been fixed in the 2.6.8 upstream Linux
kernel, this update contains a backport of the fix.
Products running a 2.4 kernel are not affected.
Mitre has assigned the CVE ID CAN-2004-0816 for this
Additionaly Martin Schwidefsky of IBM found an incorrectly
handled privileged instruction which can lead to a local user
gaining root user privileges.
This only affects the SUSE Linux Enterprise Server 9 on the
S/390 platform and has been assigned CVE ID CAN-2004-0887.
Additionaly the following non-security bugs were fixed:
- Two CD burning problems.
- USB 2.0 stability problems under high load on SMP systems.
- Several SUSE Linux Enterprise Server issues. (see the
Maintenance Information Mail for more informations).
If you are not using an iptables based firewall (like
SUSEfirewall2) on your system, you are not affected.
If you are using a firewall, a workaround is to disable firewall
logging of IP and TCP options.
We recommend to update the kernel.
3) special instructions and notes
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, the steps
outlined in a particular paragraph may or may not be applicable to
Therefore, please make sure to read through all of the steps below
before attempting any of these procedures. 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 it 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
Following are the possible kernel types (disregard the version
and build number following the name separated by the "-"
- Step 2: Download the package for your system
Please download the kernel RPM package for your distribution
with the name as indicated by Step 1. The list of all kernel rpm
packages is appended below. Note: The kernel-source package does
not contain a binary kernel in bootable form. Instead, it contains
the sources that the binary kernel rpm packages are created 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 the locations below ftp://ftp.suse.com/pub/suse/i386/update/.
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
- 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
Warning: After performing this step, your system will likely not
be able to boot if the following steps have not been fully
- Step 4: configuring and creating the initrd
The initrd is a ramdisk that is 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
The variable INITRD_MODULES in /etc/sysconfig/kernel 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
as root to create a new init ramdisk (initrd) for your system.
On SuSE Linux 8.1 and later, this is done automatically when the
RPM is installed.
- Step 5: bootloader
If you run a SUSE LINUX 8.x, SLES8, or SUSE LINUX 9.x system,
there are two options:
Depending on your software configuration, you have either the lilo
bootloader or the grub bootloader installed and initialized on your
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
- Step 6: reboot
If all of the steps above have been successfully completed on
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
have completed, then reboot using the command
shutdown -r now
Your system should now shut down and reboot with the new
4) package location and checksums
Please download the update package for your distribution and
verify its integrity by the methods listed in section 3) of this
announcement. Then, install the package using the command "rpm -Fhv
file.rpm" to apply the update.
Our maintenance customers are being notified individually. The
packages are being offered to install from the maintenance web.
SUSE Linux 9.1:
SUSE Linux 9.1:
5) Pending vulnerabilities in SUSE Distributions and
- File overwrite problems were identified in php4. We have
released updates for this issue. However, due to problems with
php4-recode in combination with php4-mysql we had to withdraw the
update from YaST2 Online Update for some SUSE Linux versions. New
packages will be available soon.
- A tempfile race condition in zinf / freeamp was fixed, packages
- A bug in phpMyAdmin that would allow users to execute arbitrary
commands has been discovered. New packages will be available
- Several bugs in mysql have been discovered. New packages will
be available soon.
- The issues with libpng described in CAN-2004-0954 and
CAN-2004-0955 where already fixed in the last libpng update. Fixed
packages are therefore already available on our ftp server.
6) standard appendix: authenticity verification, additional
- 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:
- md5sums as provided in the (cryptographically signed)
- using the internal gpg signatures of the rpm package.
- 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 firstname.lastname@example.org), 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.
- 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:
- gpg is installed
- 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@example.com"
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:
- general/linux/SUSE security discussion. All SUSE security
announcements are sent to this list. To subscribe, send an email to
- SUSE's announce-only mailing list.
Only SUSE's security announcements are sent to this list. To
subscribe, send an email to
For general information or the frequently asked questions (faq)
send mail to:
SUSE's security contact is <firstname.lastname@example.org
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.
Type Bits/KeyID Date User ID
pub 2048R/3D25D3D9 1999-03-06 SuSE Security Team <email@example.com>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <firstname.lastname@example.org>