SUSE Linux Advisory: kernel

SUSE Security Announcement

Package: Linux Kernel
Announcement-ID: SuSE-SA:2004:005
Date: Wednesday, Feb. 18th 2004 23:05 MET
Affected products: 8.0, 8.1, 8.2, 9.0 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-2004-0003 CAN-2004-0010 CAN-2004-0077

Content of this advisory:

  1. security vulnerability resolved:
    • do_mremap: insecure memory page management
    • several local denial-of-service attacks problem description,
      discussion, solution and upgrade information
  2. pending vulnerabilities, solutions, workarounds:
    • netpbm
    • zebra
    • susehelp
    • mod_gzip
    • mod_auth_shadow
    • mod_python
    • mutt
    • mailman
    • clamav
    • XFree86/xf86
    • libxml2
  3. standard appendix (further information)

1) problem description, brief discussion, solution, upgrade

Another bug in the Kernel’s do_mremap() function, which is
unrelated to the bug fixed in SuSE-SA:2004:001, was found by Paul
Starzetz. The do_mremap() function of the Linux Kernel is used to
manage Virtual Memory Areas (VMAs) which includes moving, removing
and resizing of memory areas. To remove old memory areas
do_mremap() uses the function du_munmap() without checking the
return value. By forcing do_munmap() to return an error the memory
management of a process can be tricked into moving page table
entries from one VMA to another. The destination VMA may be
protected by a different ACL which enables a local attacker to gain
write access to previous read-only pages.
The result will be local root access to the system.

Additionally to the bug mentioned above some other bugs were
fixed (depending on architecture) that can cause local
denial-of-service conditions:

  • Vicam USB driver: CAN-2004-0075

    + denial-of-service due to problem while copying data from user
    to kernel space

  • Direct Render Infrastructure: CAN-2004-0003

    + denial-of-service due to integer overflow + needs r128 card
    and console to be exploited

  • ncpfs/ncp_lookup: CAN-2004-0010

    + buffer overflow with the probability to gain root

  • execve():

    + malformed elf binaries can lead to a local denial-of-service


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, you decide
if the paragraph is needed for you or not. Please read through all
of the steps down to the end. 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 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

The following options are possible (disregarding the version and
build number following the name, separated by the “-”

      k_deflt   # default kernel, good for most systems.
      k_i386    # ke 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 starting as indicated by Step 1. The list of all
kernel rpm packages is appended below. Note: The kernel-source
package does not contain any binary kernel in bootable form.
Instead, it contains the sources that the binary kernel rpm
packages are made 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

The kernel RPM binary packages for the distributions can be
found at these 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

             able to boot if the following steps have not been fully

If you run SUSE LINUX 8.1 and haven’t applied the previous
kernel update (SUSE-SA:2003:034), AND use 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 being 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 have a 7.x system, you must now run the command


as root to initialize the lilo bootloader for your system. Then
proceed to the next step.

If you run a SUSE LINUX 8.x or a SLES8 system, there are two
options: Depending on your software configuration, you have 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


  • Step 6: reboot

If all of the steps above have been successfully applied to 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 are
complete, then reboot using the command

shutdown -r now

init 6

Your system should now shut down and reboot with the new

Our maintenance customers are being notified individually. The
packages are being offered to install from the maintenance web.

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, to apply the update use the command “rpm -Fhv
file.rpm”. Our maintenance customers are being notified
individually. The packages are being offered to install from the
maintenance web.

Due to unfinished functional evaluation testing the 8.0 kernel
will be released within the next few days.

Intel i386 Platform:



source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):





source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):





source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):




source rpm(s):



Opteron x86_64 Platform:



source rpm(s):




source rpm(s):




source rpm(s):



2) Pending vulnerabilities in SUSE Distributions and

  • netpbm Some tools in the netpbm suite create files in an
    insecure manner that can lead to local privilege escalation. New
    packages are available on our FTP servers.
  • zebra Local users can send malicious netlink messages that
    cause denial-of-service conditions in zebra. New packages are
    available on our FTP servers.
  • susehelp The susehelp package for SuSE Linux 9.0 contained CGI
    scripts which allowed remote attackers to execute arbitrary
    commands as wwwrun user. Additionally, certain ACL entries have
    been added to deny execution of the susehelp CGI scripts from
    remote. If you update your susehelp package manually, you have to
    invoke the SuSEconfig command as root afterwards. You also have to
    restart the HTTP server for the new ACLs to take effect. New
    packages are available on our FTP servers.
  • mod_gzip (apache-contrib) The apache module mod_gzip is
    vulnerable to remote code execution while running in debug-mode. We
    do not ship this module in debug-mode but future versions will
    include the fix. Additionally the mod_gzip code was audited to fix
    more possibly security related bugs. New packages are available on
    our FTP servers.
  • mod_auth_shadow (apache-contrib) This apache module ignores
    account expiration dates. The update will be released together with
    mod_gzip. New packages are available on our FTP servers.
  • mod_python A remote denial-of-service attack can be triggered
    against the Apache web server by sending a specific query string
    that is processed by mod_python. New packages will be available
  • mutt The popular email client mutt is vulnerable to a remote
    denial-of-service attack and maybe remote command execution. The
    bug can be triggered by malformed messages that overflow an
    internal buffer. New packages will be available soon.
  • mailman A remote denial-of-service attack can be triggered in
    mailman 2.0.x (CAN-2003-0991). New packages will be available
  • clamav A remote denial-of-service attack can be triggered in
    the anti-virus scanner. New packages will be available soon.
  • XFree86/xf86 Several buffer overflows in the font-alias
    handling code can lead to local root access. Packages are built and
    are being tested at the moment.
  • libxml2 Two buffer overflows in the URI code can lead to remote
    system compromise. New packages will be available soon.

3) 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



  • SUSE’s announce-only mailing list. Only SUSE’s security
    announcements are sent to this list. To subscribe, send an email


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
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 uSE Security Team <security@suse.de>
pub 1024D/9C800ACA 2000-10-19 uSE Package Signing Key <build@suse.de>

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