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SUSE Linux Advisory: kernel

Jun 18, 2004, 03:15 (0 Talkback[s])

SUSE Security Announcement

Package: kernel Announcement-ID: SuSE-SA:2004:017 Date: Wednesday, Jun 16th 2004 15:20 MEST Affected products: 8.0, 8.1, 8.2, 9.0, 9.1 SuSE Linux Database Server, SuSE eMail Server III, 3.1 SuSE Linux Enterprise Server 7, 8 SuSE Linux Firewall on CD/Admin host SuSE Linux Connectivity Server SuSE Linux Office Server Vulnerability Type: local denial-of-service attack Severity (1-10): 4 SUSE default package: no Cross References: CAN-2004-0554

Content of this advisory:

  1. security vulnerability resolved:
    • floating point exception causes system crash problem description, discussion, solution and upgrade information
  2. pending vulnerabilities, solutions, workarounds:
    • icecast
    • sitecopy
    • cadaver
    • OpenOffice_org
    • tripwire
    • postgresql
    • lha
    • XDM
    • mod_proxy 3) standard appendix (further information)

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

The Linux kernel is vulnerable to a local denial-of-service attack. By using a C program it is possible to trigger a floating point exception that puts the kernel into an unusable state. To execute this attack a malicious user needs shell access to the victim's machine.
The severity of this bug is considered low because local denial-ofservice attacks are hard to prevent in general. Additionally the bug is limited to x86 and x86_64 architecture.


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.
Note: The update packages for the SuSE Linux Enterprise Server 7 (SLES7) are being tested at the moment and will be published as soon as possible.

  • 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)
          k_deflt   # default kernel, good for most systems.
          k_i386    # kernel for older processors and chipsets
          k_athlon  # kernel made specifically for AMD Athlon(tm) family processors
          k_psmp    # kernel for Pentium-I dual processor systems
          k_smp     # kernel for SMP systems (Pentium-II and above)
          k_smp4G   # kernel for SMP systems which supports a maximum of 4G of RAM
  • 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


    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.

    If you run SUSE LINUX 8.1 and haven't applied the kernel update (SUSE-SA:2003:034), AND you are using 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

  • 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.

There is no workaround known.

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.

Intel i386 Platform:

SuSE-9.1: 8d11469e1815c5b2fa143fce62c17b95 75222182ad4c766b6482e5b83658819d 45f1244f153ab1387a9dc67e7bcf20bb 517647d955770503fe61ae2549c453dd
source rpm(s): 9103503f430b9d854630ecb8855a2fb3 9381c56f1f64835c5379dde278ac768d 4f47dc2be58f5315cf596c051c2892b5 732c1e7d2a9e41780464eccdc0d54505

SuSE-9.0: 7b6022e2f80325b42fa7dc3188360530 594efe04ccc233e890bfb277e8296c2d f41d088cf20bfe583e57f95a6b46d625 39e2c09ece3f22b50eb777b85a7218ef 83398954810403b9dfb65bcf1af25352 18dde4a8af68dd1f78a0177c3214457a
source rpm(s): d5b037aaf122b1b05917e3f0b475baae e10aea97785eb12716ad7d5e20cbd723 54b8bbd368998abc1a63224caa880473 f944b14978ecd211c26f8169238292bf 66a116aeb9757c538a0643e8322095a7 5e3694ba088fd39891a5979380679d20

SuSE-8.2: a5843cb4e2b16515d70574d83113ac48 724529485d3a304f0479f9216fc361af b0e687c208053d546b7057257beb7d32 749b101e7fc4aa5c62e2a5b650002803 3377544a5f6d9c73fdfe05140fce0813
source rpm(s): 0a41c750b8cd3953d47e27ea15c58697 a5e5790e5f7fe62905d29750543c9e20 9defa7cb706e924f8336dd03fafbcfd5 8469dbc8810dd292100d085e00bb6081 d990fcbace1f21ff383abdf7608a17ef

SuSE-8.1: 43ee5eae102f0258a414dd15e3fd9433 0c6289e168307d615bfe6cef9ebcf879 003a38c53fe91070eeae85983930c70e 657d08fa4b5a2ba7de2a314a7d1622e1 e19239b4ca52ebd21f775b5e6195f144
source rpm(s): ee67f5db0ea2f1431f46b7dd27815a56 b29021156d6582e315666b16231b2a60 ce5e47d527cee6968cd95bb8430d3e18 a081a0f1e31f5491cdeba1fea5ea6411 1dbfd3b5f272fc75342ae55bbe7ab45c

SuSE-8.0: 7de319a4e6c667fba359686b814d4a73 df5aad7c423625a19af151bbba0f2ca8 cb02c8381962eda997ebb115ef68ae4c 903c6e61927803c2d592ac50fe9da6ce e2abf9ccdc8191e7d2ace58e8a1b5b5a
source rpm(s): 622c85342dd84abd0400103902d05eed 37916ea39febc4dd43fabfccce9322db 0dde0e6758e42de5479e8776475ae76f 523bef4e31fa67f078d5fcbdc426a4c0 06a2a062a54764a30adae0b8ea40cb29

Opteron x86_64 Platform:

SuSE-9.1: 1c878b1e29a9bea40547637b6a307b2d 16de3ee2390bb2b92f9fe50451d4f082 c310268daa83f18fcfd4cf19434f06e0
source rpm(s): 2fed0a8f3936027261add7d1cbfa5341 9ad26d15566337c83273121390ea4e32 352951be42b3093efb0148320a6f4c27

SuSE-9.0: ced9c66ffa28bf7e7c795781f92083fe 60539bc47e8cac0664ac5ca824d311e0 083aeedd2a88ccc2e00c8f66cd61b81c
source rpm(s): 58c40a206f6f615daa3486fc6d6ade38 1c234f6c0475680b41c644c575ff8ef6 e9b90824615859405b1979793662bc0d

2) Pending vulnerabilities in SUSE Distributions and Workarounds:

  • icecast
    The icecast service is vulnerable to a remote denial-of-service attack. Update packages will be available soon.
  • sitecopy
    The sitecopy package includes a vulnerable version of the neon library (CAN-2004-0179, CAN-2004-0398). Update packages will be available soon.
  • cadaver
    The cadaver package includes a vulnerable version of the neon library (CAN-2004-0179, CAN-2004-0398). Update packages will be available soon.
  • OpenOffice_org
    The OpenOffice_org package includes a vulnerable version of the neon library (CAN-2004-0179, CAN-2004-0398). Update packages will be available soon.
  • tripwire
    A format string bug in tripwire can be exploited locally to gain root permissions. Update packages will be available soon.
  • postgresql
    A buffer overflow in psqlODBC could be exploited to crash the application using it. E.g. a PHP script that uses ODBC to access a PostgreSQL database can be utilized to crash the surrounding Apache web-server. Other parts of PostgreSQL are not affected. Update packages will be available soon.
  • lha
    Minor security fix for a buffer overflow while handling command line options. This buffer overflow could be exploited in conjunction with other mechanisms to gain higher privileges or access the system remotely.
  • XDM/XFree86
    This update resolves random listening to ports by XDM that allows to connect via the XDMCP. SUSE LINUX 9.1 is affected only. New packages are currently being tested and will be available soon.
  • mod_proxy
    A buffer overflow can be triggered by malicious remote servers that return a negative Content-Length value. This vulnerability can be used to execute commands remotely New packages are currently being tested and will be available soon.

3) standard appendix: authenticity verification, additional information

  • Package authenticity verification:

    SUSE update packages are available on many mirror ftp servers around the world. While this service is considered valuable and important to the free and open source software community, many users wish to be certain as to be the origin of the package and its content before installing the package. There are two independent verification methods that can be used 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 have 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, the checksums offer proof of the authenticity of the package.
      We recommend against subscribing 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.
      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 "" 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 .
  • 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:

<> or
<> respectively.

SUSE's security contact is <> or <>.
The <> 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 must show 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 <>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <>