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SuSE: various kernel problems Print E-mail
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Posted by Joe Shakespeare   
SuSE Several security problems have been found and addressed by the SUSE Security Team. The following issues are present in all SUSE Linux based products.

______________________________________________________________________________

                        SUSE Security Announcement

        Package:                kernel
        Announcement-ID:        SUSE-SA:2004:042
        Date:                   Wednesday, Dec 1st 2004 15:00 MEST
        Affected products:      8.1, 8.2, 9.0, 9.1, 9.2
                                SUSE Linux Enterprise Server 8, 9
                                SUSE LINUX Desktop 1.0
                                Novell Linux Desktop 9
        Vulnerability Type:     local and remote denial of service
        Severity (1-10):        7
        SUSE default package:   yes
        Cross References:       CAN-2004-0883
                                CAN-2004-0949
                                CAN-2004-1070
                                CAN-2004-1071
                                CAN-2004-1072
                                CAN-2004-1073
                                CAN-2004-1074

    Content of this advisory:
        1) security vulnerability resolved:
             - kernel remote and local denial of service problems
           problem description
        2) solution/workaround
        3) special instructions and notes
        4) package location and checksums
        5) pending vulnerabilities, solutions, workarounds:
            - see SUSE Security Summary Report
        6) standard appendix (further information)

______________________________________________________________________________

1) problem description, brief discussion

    The Linux kernel is the base of the SUSE Linux system.

    Several security problems have been found and addressed by
    the SUSE Security Team. The following issues are present
    in all SUSE Linux based products.

    - Several remote denial of service conditions have been found in
      the smbfs file system, reported by Stefan Esser.
      The vulnerability could be used by a hostile SMB server (or an
      attacker injecting packets into the network) to crash the clients
      kernel.
      These issues have been assigned the Mitre CVE IDs CAN-2004-0883 and
      CAN-2004-0949.

      We thank Stefan Esser for reporting this issue and providing patches.


    - Paul Starzetz of isec.pl found several missing boundary checks
      in the ELF loader routines of the Linux kernel which could
      potentially lead a local attacker to gain root privileges by using
      handmade ELF binaries. These issues have been assigned the Mitre
      CVE IDs CAN-2004-1070,CAN-2004-1071,CAN-2004-1072, and CAN-2004-1073.

      We thank Paul for reporting this issue and Chris Wright for providing
      a patch to fix the issue.

    - Handcrafted a.out binaries could be used to trigger a local
      denial of service condition in both 2.4 and 2.6 Linux kernels, allowing
      a local attacker to render the system unusable.
      Fixes for this problem were done by Chris Wright.
      This issue has been assigned the Mitre CVE ID CAN-2004-1074.

      We wish to thank Chris for providing patches.


    - SUSE Linux 9.1 and SUSE Linux Enterprise Server 9 now contain
      stricter checks what commands you can send to read-only opened
      CD devices. This way local attackers only having read access to
      the device will not be able to destroy the firmware of SCSI related
      devices.

      This update will break the k3b and the dvd+rw-tools packages.
      We have released fixed versions of those packages.


    - The SUSE Linux 8.1, 8.2, and 9.0 and the SUSE Linux Desktop 1.0
      kernel were missing the kNFSD remote denial of service fix. The
      respective fixes are now in the released kernels.


    Also, the following critical bugs were fixed by this update:

    - A very small race condition on SMP systems with more than 4GB of
      memory that could expose foreign memory pages was found and fixed
      by Andrea Arcangeli of SUSE.

    - On SUSE Linux Enterprise Server 9 a memory corruption in the NFS
      readdirplus command could lead to kernel crashes and potentially
      corruption of data on disk. This problem was fixed.

    - On SUSE Linux 9.2 the "dazuko" kernel module of the "antivir" RPM
      package caused problems with programs using Linux capabilities.
      The module was fixed.

    - A security fix for buffer overflows in the decnet protocol
      driver was incorrect and caused kernel crashes.


2) solution/workaround

    There is no workaround, please install the fixed kernels.


3) special instructions and notes

    SPECIAL INSTALL INSTRUCTIONS:
    ==============================
    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)

      k_deflt   # default kernel, good for most systems.
      k_i386    # kernel for older processors and chip sets
      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
      kernel-64k-pagesize
      kernel-bigsmp
      kernel-default
      kernel-smp

  **** 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/.

      8.1/rpm/i586
      8.2/rpm/i586
      9.0/rpm/i586
      9.1/rpm/i586
      9.2/rpm/i586

    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 
    where  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
    ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/

  **** 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

      mk_initrd

    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
    or
        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.

    

______________________________________________________________________________

5)  Pending vulnerabilities in SUSE Distributions and Workarounds:

    Please see our weekly summary report.

______________________________________________________________________________

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.

    1) execute the command
        md5sum 
       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.

    2) rpm package signatures provide an easy way to verify the authenticity
       of an rpm package. Use the command
        rpm -v --checksig 
       to verify the signature of the package, where  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:
        a) gpg is installed
        b) 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:

    suse-security@suse.com
        -   general/linux/SUSE security discussion.
            All SUSE security announcements are sent to this list.
            To subscribe, send an email to
                .

    suse-security-announce@suse.com
        -   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 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.

 
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