SUSE Linux Advisory: kernel

Sep 02, 2004, 16:44 (0 Talkback[s])

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:

security vulnerability resolved:
- integer overflow in kNFSd
- local denial-of-service condition via /dev/ptmx problem description
solution/workaround
special instructions and notes
package location and checksums
pending vulnerabilities, solutions, workarounds:
- zlib
- courier-imap
- gaim
- acroread
- opera
- netpbm/libnetpbm
- webmin
- spamassassin/perl-spamassassin
- cfengine
- xv
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 vulnerability.
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

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.
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
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/.

8.0/images/
8.1/rpm/i586
8.2/rpm/i586
9.0/rpm/i586
9.1/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 <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 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

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:

x86-64 Platform:

5) Pending vulnerabilities in SUSE Distributions and Workarounds:

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 servers.
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 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.
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:
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-subscribe@suse.com>.

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
<suse-security-announce-subscribe@suse.com>.

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 <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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