SUSE Security Announcement: kernel (SUSE-SA:2004:020)

From: Roman Drahtmueller (
Date: 07/02/04

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    Date: Fri, 2 Jul 2004 18:48:27 +0200 (MEST)



                            SUSE Security Announcement

            Package: kernel
            Announcement-ID: SUSE-SA:2004:020
            Date: Tuesday, Jul 2nd 2004 18:00 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 privilege escalation
            Severity (1-10): 6
            SUSE default package: yes
            Cross References: CAN-2004-0495

        Content of this advisory:
            1) security vulnerability resolved:
                    - chown: users can change the group affiliation of arbitrary
                      files to the group they belong to
                    - missing DAC check in chown(2): local privilege escalation
                    - overflow with signals: local denial-of-service
                    - pss, mpu401 sound driver: read/write to complete memory
                    - airo driver: read/write to complete memory
                    - ALSA: copy_from_user/copy_to_user confused
                    - acpi_asus: read from random memory
                    - decnet: write to memory without checking
                    - e1000 driver: read complete memory
               problem description, discussion, solution and upgrade information
            2) pending vulnerabilities, solutions, workarounds:
                    - icecast
                    - sitecopy
                    - cadaver
                    - OpenOffice_org
                    - tripwire
                    - postgresql*
                    - mod_proxy
                    - freeswan
                    - ipsec-tools
                    - less
                    - libpng
                    - pavuk
                    - XFree86*
                    - kdebase3
            3) standard appendix (further information)


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

        Multiple security vulnerabilities are being addressed with this security
        update of the Linux kernel.

        Kernel memory access vulnerabilities are fixed in the e1000, decnet,
        acpi_asus, alsa, airo/WLAN, pss and mpu401 drivers. These
        vulnerabilities can lead to kernel memory read access, write access
        and local denial of service conditions, resulting in access to the
        root account for an attacker with a local account on the affected

        Missing Discretionary Access Control (DAC) checks in the chown(2) system
        call allow an attacker with a local account to change the group
        ownership of arbitrary files, which leads to root privileges on affected
        systems. It is specific to kernel version 2.6 based systems such as
        the SUSE Linux 9.1 product, that only local shell access is needed to
        exploit this vulnerability. An interesting variant of the missing
        checks is that the ownership of files in the /proc filesystem can be
        altered, while the changed ownership still does not allow the files to
        be accessed as a non-root user for to be able to exploit the
        vulnerability. Systems that are based on a version 2.4 kernel are not
        vulnerable to the /proc weakness, and exploitation of the weakness
        requires the use of the kernel NFS server (knfsd). If the knfsd NFS
        server is not activated (it is off by default), the vulnerability is
        not exposed. These issues related to the chown(2) system call have been
        discovered by Michael Schroeder and Ruediger Oertel, both SUSE LINUX.

        The only network-related vulnerability fixed with the kernel updates
        that are subject to this announcement affect the SUSE Linux 9.1
        distribution only, as it is based on a 2.6 kernel. Found and reported
        to bugtraq by Adam Osuchowski and Tomasz Dubinski, the vulnerability
        allows a remote attacker to send a specially crafted TCP packet to a
        vulnerable system, causing that system to stall if it makes use of
        TCP option matching netfilter rules.

        In some rare configurations of the SUSE Linux 9.1 distribution, some
        users have experienced stalling systems during system startup. These
        problems are fixed with this kernel update.

        For the impatient: Run YOU (Yast2 Online Update, command
        "yast2 online_update" as root) to install the updates (semi)
        automatically, if you have a SUSE Linux 8.1 and newer system.

        For those who wish to install their kernel updates manually and for
        those who use a SUSE Linux 8.0 system:

        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 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

        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

        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
        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

      **** 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.

        x86 Platform:

        SUSE Linux 9.1:
        source rpm(s):

        SUSE Linux 9.0:
        source rpm(s):

        SUSE Linux 8.2:
        source rpm(s):

        SUSE Linux 8.1:
        source rpm(s):

        SUSE Linux 8.0:
        source rpm(s):

        x86-64 Platform:

        SUSE Linux 9.1:
        source rpm(s):

        SUSE Linux 9.0:
        source rpm(s):


    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.
        New packages are available.

        - 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.
        New packages are available.

        - 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 available.

        - 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 available.

        - freeswan
        A bug in the certificate chain authentication code could allow an
        attacker to authenticate any host against a FreeS/WAN server by
        presenting specially crafted certificates wrapped in a PKCS#7 file.
        The packages are currently being tested and will be available soon.

        - ipsec-tools
        The racoon daemon which is responsible for handling IKE messages
        fails to reject invalid or self-signed X.509 certificates which
        allows for man-in-the-middle attacks on IPsec tunnels established
        via racoon.
        The packages are currently being tested and will be available soon.

        - less
        This update fixes a possible symlink attack in The
        attack can be executed by local users to overwrite arbitrary files
        with the privileges of the user running less.
        New packages are available.

        - libpng
        This update adds a missing fix for CAN-2002-1363.
        New packages are available.

        - pavuk
        This update fixes a remotely exploitable buffer overflow in pavuk.
        Thanks to Ulf Harnhammar for reporting this to us.
        New packages are available.

        - kdebase3
        This update fixes a possible attack on tmp files created at the
        first login of a user using KDE or at the first time running a
        KDE application. This bug can be exploited locally to overwrite
        arbitrary files with the privilege of the victim user.
        Just affects SUSE LINUX 9.1
        New packages are available.


    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.

        1) 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.

        2) 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.
            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 "" 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
            - 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 <>

    #####-----BEGIN PGP PUBLIC KEY BLOCK-----
    Version: GnuPG v1.0.6 (GNU/Linux)
    Comment: For info see

    - -----END PGP PUBLIC KEY BLOCK-----

    - --
     - -
    | Roman Drahtmüller <> // "You don't need eyes to see, |
      SUSE Linux AG - Security Phone: // you need vision!"
    | Nürnberg, Germany +49-911-740530 // Maxi Jazz, Faithless |
     - -
    Version: GnuPG v1.0.7 (GNU/Linux)

    -----END PGP SIGNATURE-----

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