SUSE Linux Advisory: kernel

SUSE Security Announcement

Package: kernel
Announcement-ID: SUSE-SA:2004:037
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:

  1. security vulnerability resolved:
    • remote system crash with enabled firewall
    • local root exploit on the S/390 platform
    • minor /proc information leaks problem description
  2. solution/workaround
  3. special instructions and notes
  4. package location and checksums
  5. pending vulnerabilities, solutions, workarounds:
    • libtiff
    • cyrus-sasl
    • php4
    • zinf

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
firewalling enabled.

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).

2) solution/workaround

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
your situation.
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
    diskless operation.

    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
    system unbootable.

  • 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

    init 6

    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.

x86 Platform:

SUSE Linux 9.1:






source rpm(s):







x86-64 Platform:

SUSE Linux 9.1:




source rpm(s):





5) Pending vulnerabilities in SUSE Distributions and


  • Several buffer and integer overflows have been found in the
    image handling library libtiff by Chris Evans and Dmitry Levin,
    recorded under CVE Ids: CAN-2004-0803,CAN-2004-0804,CAN-2004-0886.

    We are working on updates and will release them within the next


  • The SASL_PATH environment variable was also used to load
    plugins even with setuid privileges set, which can lead to a local
    root privilege escalation.

    The default SUSE installation was not found to be affected by
    this problem, neithertheless we are in the process of releasing
    updates. The CVE ID for this issue is: CAN-2004-0884


  • 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
    are available.


  • 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:

    1. md5sums as provided in the (cryptographically signed)
    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]>
    <[email protected]>

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.

Type Bits/KeyID Date User ID
pub 2048R/3D25D3D9 1999-03-06 SuSE Security Team <[email protected]>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <[email protected]>