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SUSE Linux Advisory: kernel

Oct 22, 2004, 15:57 (3 Talkback[s])

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 problem.

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 problem.

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 "-" character)

  • 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 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 followed.

  • 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 command


    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 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 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 kernel.

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:
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-default-2.6.5-7.111.i586.rpm 735f99730442772d0caeb1043576da0e
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-smp-2.6.5-7.111.i586.rpm 8e38495a90203fdeef0167126e9699fd
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/i586/kernel-bigsmp-2.6.5-7.111.i586.rpm 54474a313ff90c5a5ded8cd3590016ee
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-default-2.6.5-7.111.nosrc.rpm 60a46f48bbae6989a50d2b3c735cd176
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-smp-2.6.5-7.111.nosrc.rpm 5bc77692dc82521b83378c97d39acd72
ftp://ftp.suse.com/pub/suse/i386/update/9.1/rpm/src/kernel-bigsmp-2.6.5-7.111.nosrc.rpm 348c5d63b8c26c548d8b5bfcc894b805

x86-64 Platform:

SUSE Linux 9.1:
ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/x86_64/kernel-default-2.6.5-7.111.x86_64.rpm 53ec1285f8933f79b6e53f2cb4d2094a
ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/x86_64/kernel-smp-2.6.5-7.111.x86_64.rpm de3bf18c94d26a2b3477cf11cf723380
source rpm(s):
ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/src/kernel-default-2.6.5-7.111.nosrc.rpm 3e6123bd50f2802cf6a96ccfa2af674f
ftp://ftp.suse.com/pub/suse/x86_64/update/9.1/rpm/src/kernel-smp-2.6.5-7.111.nosrc.rpm 365354d9e91032e53436f949da6ae8f6

5) Pending vulnerabilities in SUSE Distributions and Workarounds:


  • 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 days.


  • 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 soon.


  • 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 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 security@suse.de), 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 "build@suse.de" 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-security-info@suse.com> or
    <suse-security-faq@suse.com> respectively.

SUSE's security contact is <security@suse.com> or <security@suse.de>. The <security@suse.de> 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 <security@suse.de>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <build@suse.de>