SUSE Linux Advisory: kernel

SUSE Security Announcement

Package: kernel
Announcement-ID: SUSE-SA:2004:028
Date: Wednesday, Sept 1st 2004 14:26 MEST
Affected products: 8.1, 8.2, 9.0, 9.1 SUSE Linux Database Server,
SUSE eMail Server III, 3.1 SUSE Linux Enterprise Server 8, 9 SUSE
Linux Connectivity Server SUSE Linux Office Server
Vulnerability Type: remote denial-of-service
Severity (1-10): 6
SUSE default package: yes
Cross References: none

Content of this advisory:

  1. security vulnerability resolved:
    • integer overflow in kNFSd
    • local denial-of-service condition via /dev/ptmx problem
  2. solution/workaround
  3. special instructions and notes
  4. package location and checksums
  5. pending vulnerabilities, solutions, workarounds:
    • zlib
    • courier-imap
    • gaim
    • acroread
    • opera
    • netpbm/libnetpbm
    • webmin
    • spamassassin/perl-spamassassin
    • cfengine
    • xv
  6. standard appendix (further information)

1) problem description, brief discussion

Various signedness issues and integer overflows have been fixed
within kNFSd and the XDR decode functions of kernel 2.6. These bugs
can be triggered remotely by sending a package with a trusted
source IP address and a write request with a size greater then
2^31. The result will be a kernel Oops, it is unknown if this bug
is otherwise exploitable yet.
Kernel 2.4 nfsd code is different but may suffer from the same
Additionally a local denial-of-service condition via /dev/ptmx,
which affects kernel 2.6 only has been fixed. Thanks to Jan
Engelhardt for reporting this issue to us.

This update also fixes several non security bugs, including:

  • CD and DVD writing of non-data media was leaking huge amounts
    kernel memory.
  • Fixed barrier issues on some IDE devices. “barrier=none” should
    not be needed anymore.

2) solution/workaround

We recommend to update the kernel or, as a temporary workaround,
block NFS traffic at your firewall or to switch back to the
user-space NFS daemon.

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
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 “-”

    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
    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

  • 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

    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


    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

    init 6

    Your system should now shut down and reboot with the new

4) package location and checksums

Note: 2.4 kernels will be delivered later.

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

  • zlib
    A Denial of Service condition has been found in the inflate
    function of zlib 1.2. This version of zlib is only shipped with
    SUSE Linux 9.1 and SUSE Linux Enterprise Server 9 and is not
    integrated in other packages which commonly use zlib (OpenSSH,
    Kernel etc). New packages will soon be available on our FTP
  • courier-imap
    A format string bug has been found in the courier IMAP server,
    which can only happen when debugging is enabled. Since this is not
    the default configuration on SUSE Linux products, the impact of
    this bug is very minor. The courier-imap packages will be fixed
    with the next version of SUSE Linux.
  • gaim
    Various buffer overflow conditions have been found in the gaim
    instant messenger. The MSN protocol parsing has already been fixed
    with the packages announced in the SUSE Security Announcement
    SUSE-SA:2004:025. The packages which fix the other pending bugs in
    gaim will be available on our FTP servers soon.
  • acroread
    A buffer overflow and a shell metacharacter problem within the
    acrobat reader has been fixed. This allowed attackers to execute
    arbitrary commands by providing malformed documents to an user. New
    packages are already available on our FTP servers.
  • opera
    The web-browser opera is affected by several security bugs. New
    packages will soon be available on our FTP servers.
  • netpbm/libnetpbm
    Some tools of the netpbm suite create files in an insecure manner
    that can lead to local privilege escalation. New packages are
    available on our FTP servers.
  • webmin
    Several bugs in webmin were fixed. These bugs allowed unauthorized
    reading of the configuration of any module, locking valid accounts
    by sending bogus passwords, and insecure handling of temporary
    files. New packages are available on our FTP servers.
  • spamassassin/perl-spamassassin
    This update fix’ a remote denial-of-service condition in
    SpamAssassin. New packages are available on our FTP servers.
  • cfengine
    This update resolves a heap corruption bug in the RSA
    authentication code of cfservd which can be exploited remotely to
    execute arbitrary code as root. Another bug leads to a remotely
    triggerable crash of the cfservd to deny service. For a successful
    attack the attacker has to bypass the IP Access Control Lists
    (ACLs). New packages are available on our FTP servers.
  • xv
    The xv image viewer code contains several buffer and heap overflows
    which may allow attackers to use malformed image files to execute
    code on the victim system remotely. New packages are available on
    our FTP servers.

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 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’s security contact is <security@suse.com> or
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>

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