-----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: kernel Announcement-ID: SuSE-SA:2001:18 Date: Thursday, May 17th, 2000 16:40 MET Affected SuSE versions: (6.1, 6.2), 6.3, 6.4, 7.0, 7.1 Vulnerability Type: local root compromise Severity (1-10): 7 SuSE default package: yes Other affected systems: All Linux systems using a v2.2 kernel Content of this advisory: 1) security vulnerability resolved: kernel Problem, Workaround, Recommended solution, Instructions, Notes, Verification 2) Acknowledgements 3) standard appendix (further information) ______________________________________________________________________________ 1) The Problem, Workaround, Recommended solution, Instructions, Notes, Verification The Problem: The SuSE Linux kernel is a standard kernel, enhanced with a set of additional drivers and other improvements, to suit the end-user's demand for a great variety of drivers for all kind of hardware. Multiple security vulnerabilities have been found in all Linux kernels of version 2.2 before version 2.2.19. Most of the found errors allow a local attacker to gain root privileges. None of the found errors in the v2.2 linux kernel make it possible for a remote attacker to gain access to the system or to elevate privileges from the outside of the system. Thanks to Alan Cox, a summary of these errors can be found at http://www.linux.org.uk/VERSION/relnotes.2219.html . One of the numerous features in the SuSE Linux kernels is support for reiserfs, a fast, stable logging filesystem. In addition to the bugs listed at www.linux.org.uk, the SuSE Linux kernel contains a fix for a race condition between mmap(2) and write(2) in reiserfs that can expose raw data from the disk to an unprivileged user (this problem affected the ufs and ext2fs drivers in FreeBSD systems, see FreeBSD-SA-01:30.ufs-ext2fs at http://www.freebsd.org/security/). Please see the acknowledgement section 2) below for credits on hunting these bugs and fixing them. Workarounds: In order to solve the security problems, it is recommended to update the kernel to version 2.2.19. Some problems (ptrace race) can be circumvented by removing all suid and sgid bits from all binaries in the system. Since this does not help against the other errors, there is no appropriate temporary workaround against all of the known problems except for locking out users with shell access. Advanced Linux users may decide to compile and install the 2.2.19 kernel themselves by hand. This requires some experience on behalf of the administrator and may not be all satisfying because the standard 2.2.19 kernel does not contain some of the drivers that are included in the SuSE kernel (ppp over ethernet, hardware health monitoring (SMBus), reiserfs, graphics hardware acceleration modules (DRI), ...). Recommended solution: SuSE have chosen to provide update packages for the supported distributions to the newest kernels instead of supplying patched update kernel packages of the same kernel version in order to avoid confusion about whether a vulnerable version of a kernel is installed on a system or not. In addition to the clarifying effect of a visible new kernel version that is known to have all publically known security problems fixed, SAP LinuxLab (http://www.sap.com/linux/) have certified this release of the SuSE-enhanced Linux kernel version 2.2.19 with respect to stability and performance. We expect that our usership will benefit from this achievement. Currently, only kernel update packages for the Intel i386 distributions are available. The other supported architectures will have their kernel updates in their respective update directories on our ftp server. The SuSE Linux distribution 6.0 was shipped with a kernel of version 2.0. All of the SuSE Linux distributions 6.1, 6.2, 6.3, 6.4, 7.0 and 7.1 are ready for a kernel of version 2.2.19. However, since update support for the SuSE Linux distributions 6.0, 6.1 and 6.2 has been discontinued, we strongly encourage all users of these distributions to update their systems to a newer version of the SuSE Linux distribution. Please know that the full distribution can be installed from our ftp server or one of its mirrors. Experienced Linux users may choose to update their kernels by hand to the latest version 2.2.19. Step-By-Step Installation Instructions: The kernel of a Linux/Un*x system is the most critical component with relation to stability, reliability and security. By consequence, an update of that component requires some care and full attention to succeed. 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 be successfully completed. **** Step 1: Determine the needed RPM package Use the command rpm -qf `awk -F= '/image/{print $2}' < /etc/lilo.conf` to find the name of the kernel RPM package that is installed on your system. Get the respective kernel RPM package from the following location: ftp://ftp.suse.com/pub/suse/i386/update/<DIST>/kernel/2.2.19/ where <DIST> is the distribution version of your system (one out of 6.3, 6.4, 7.0 or 7.1). Most installations are likely to run a k_deflt kernel. To verify the integrity of the files that you need to download, see the section "Verification" near the end of this announcement. In SuSE-6.3 distributions, the above command can produce inconclusive results. This is caused by a different kernel installation procedure in this version of the SuSE Linux distribution. To select your kernel type, choose from the following options: k_eide - should be used for "exotic" IDE chipsets, mostly found on additional IDE interface adapters to PCI or ISA bus systems. k_laptop - should be used for laptops. This kernel has APM support configured. k_i386 - a kernel that should run on most i386 processors. Use this kernel package if the k_pentiu kernel will not boot. k_smp - kernel for multiprocessor systems (SMP) k_pentiu - the standard kernel. It should run on most systems. In the case that you have a self-compiled kernel running on your system, please note that most kernels for the newer distributions have APM configured. This obsoletes the need for a particular laptop kernel. k_deflt (after SuSE-6.3) should do on most modern hardware. **** Step 2: SuSE-6.3 special If you have a SuSE-6.3 system, continue to read this paragraph, otherwise jump to Step 3. In SuSE Linux version 6.3, the kernel and the kernel modules are packaged in two different packages. Both packages must be downloaded and installed. On SMP systems, the packages kernmods (-> kernmod-SMP) and k_smp are needed. On single processor systems, get the kernmod package plus the package as determined by the description in Step 1. **** Step 3: Installation of the RPM package Install the rpm package using the command rpm -Uhv where is the rpm package you downloaded in Step 1 (for 6.3 also Step 2, two packages!). If the RPM command complains about conflicting files or unfulfilled dependencies, use the options "--nodeps" and "--force". In this case there is no risk for the consistency of the packages on your system. **** Step 4: aic7xxx If you use an Adaptec aic7xxx SCSI host adapter, continue to read this paragraph, otherwise jump to Step 5. The new kernel comes with two versions for the Adaptec aic7xxx driver. If you have such a card, you should see the driver listed in the output from the command lsmod or you should see the adapter in the output of the command lspci The new driver is known to work reliably. However, if you encounter any problems with CDROM drives or other removeable devices (CD-RW drives, tapes, etc) after this kernel upgrade, then you should try to use the old driver which is called aic7xxx_old instead of aic7xxx. If you decide to make this change, then the steps 6 and 7 are mandatory for the update to succeed, regardless if you get back to this paragraph after your first reboot or not. To use the old driver, please use your favourite editor to edit the file /etc/rc.config. Change aic7xxx into aic7xxx_old at the line that starts with INITRD_MODULES. You should find it near the top of the file. Do not forget to save your changes. Then go to Steps 6 and 7. If you want to use the new driver, then do not change anything. **** Step 5: LVM If you use LVM, then continue to read this paragraph, otherwise jump to Step 6. If you use LVM (Logical Volume Manager) in your installation of SuSE Linux, then you need the updated lvm package from the kernel/2.2.19/ directory for your distribution as well. The package contains the userspace utilities to manage the Logical Volume Manager driver. An update package is needed because the LVM data format/structure on disk has changed with the new version of the LVM kernel driver. Install the package as usual using the command rpm -Uhv lvm-0.9.1_beta4-12.i386.rpm Be sure you have downloaded the package for the explicit version of your SuSE Linux Installation. The package names are identical for all distribution versions. WARNING: After the first boot with the new kernel you will not be able to downgrade to older versions of LVM any more. **** Step 6: initrd Upon kernel boot (after lilo runs), the kernel needs to use the drivers for the device (disk/raid) where the root filesystem is located. If this driver is not compiled into the kernel, it is supplied as a kernel module that must be loaded _before_ the root filesystem is mounted. This is done using a ramdisk that is loaded along with the kernel by lilo (See next Step). This ramdisk, called "initrd", must be generated using the command mk_initrd The modules as configured in the variable INITRD_MODULES from /etc/rc.config (See Step 4) are being added to the initrd. Without the "mk_initrd"-call your system might not boot any more. **** Step 7: lilo lilo is responsible for loading the kernel image and the initrd ramdisk image into the system and for transferring control over the system to the kernel. Therefore, a proper installation of the bootloader (by calling the program lilo) is essential for the system to boot (!). Manually changed settings in /etc/lilo.conf require the admin to make sure that /boot/vmlinuz is listed in the first "image" line in that file. Verify that the line starting with initrd= is set to initrd=/boot/initrd Execute lilo and you should see your label in an output like Added linux * Every other output should be considered an error and requires attention. If your system managed to reboot before the upgrade, you should not see any additional output from lilo at this stage. **** Step 8: SuSE-7.0 special If you have a SuSE Linux 7.0 distribution, then continue to read this paragraph, otherwise jump to Step 9. During testing of the 2.2.19-SuSE Linux kernel, we have found an error in the glibc (shlibs) package of the SuSE Linux 7.0 distribution. The error might result in readdir(3) calls to return -EIO to the user program due to incorrect handling of the return value of getdents(2) from the kernel. This bug mostly appears on NFS-mounted filesystems when commands such as tar(1) are used. We have prepared update packages that solve this specific problem. Former security updates are included in this package, of course. Determine which packages you need: See the output of the command rpm -q shlibs libc libd nssv1 It should not be necessary to update a package that is not installed. Select the needed update packages and download them from the following list of URLs ftp://ftp.suse.com/pub/suse/i386/update/7.0/a1/shlibs-2.1.3-193.i386.rpm ftp://ftp.suse.com/pub/suse/i386/update/7.0/a1/nssv1-2.1.3-193.i386.rpm ftp://ftp.suse.com/pub/suse/i386/update/7.0/d1/libc-2.1.3-193.i386.rpm ftp://ftp.suse.com/pub/suse/i386/update/7.0/d2/libd-2.1.3-193.i386.rpm !!! !!! WARNING: !!! !!! After download and before installation of the glibc packages, the system should be brought to single user mode ("init 1"). If this is not suitable for operational reasons, then please keep the system as calm as at all possible during the update of the shlibs and nssv1 packages. In particular, do not run any shell scripts or any other processes that execute other binaries. Stop the cron and at services, and shut down your MTA. Suspend the execution of active processes by killing them with the -STOP signal and let them resume their work after the installation of the shlibs and nssv1 packages with a -CONT signal. After verifying that the right conditions are in place, install the packages using the command rpm -Fhv nssv*.rpm shlibs*.rpm rpm -Fhv <rest> Afterwards, execute the command ldconfig to update the cache for the dynamic linker. NOTE: updating shared libraries in the running system requires enough space on the root and /usr filesystem to keep both versions of the shared libraries on the disk. The old libraries will be deleted, but the files continue to use diskspace until they are not used by any processes any more. (See Step 9). Similar considerations apply for the the memory consumption of the system. **** Step 9: reboot Reboot your machine for the new kernel to boot and therefore become active. Make sure that all of the above steps have completed successfully. Shutdown and reboot using the command shutdown -r now or init 6 Notes: a) After the upgrade, you might notice kernel messages upon execution of an NFS mount command: silence kernel: nfs warning: mount version older than kernel These messages are complaints that the mount(8) command needs to be upgraded. The mount(8) command is contained in the package "util" ("util-linux" for SuSE-7.1) - we will provide update packages for the "util" ("util-linux" for SuSE-7.1) package. The change is mostly a cosmetic nature and does not have any impact on the security or the stability of the system. b) The kernel sources are contained in the RPM kernel/2.2.19/lx_sus22-2.2.19.SuSE-25.i386.rpm in each distribution update tree. The kernel documentation is in the package kernel/2.2.19/lx_doc22-2.2.19.SuSE-25.i386.rpm and installs to the base path /usr/share/doc/kernel/. c) The directory kernel/misc/ in each distribution tree contains the .config files, the spec and changes file as well as the compilation output for the respective kernel, each in a directory where it belongs to. In addition, the sources for the lvm package can be found in the lvm directory as appropriate. Known problems: * The kernel modules for the cipe and the freeswan packages are not contained in the kernel RPM packages. If you use these packages, then you should wait with the kernel update until the kernel modules for these packages are available, or you could recompile the kernel modules yourself (See section Notes b). Please read the section 2) of the upcoming SuSE security announcements for the location of the cipecb.o and ipsec.o kernel modules. Verification: All RPM packages are gpg-signed using the build@suse.de SuSE packaging key that can be found in the toplevel directory of the first CD on SuSE-7.1 and younger, as well as at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de (this key is signed by security@suse.de). All files that are needed or referred to in this announcement have their md5 sums listed in the file ftp://ftp.suse.com/pub/suse/i386/update/<dist>/kernel/MD5SUMS . These files are signed by security@suse.de in the file MD5SUMS.sig. Since there are 150 files, we do not send the md5sums with the mail this time. ______________________________________________________________________________ 2) Acknowledgements SuSE Security wishes to express their gratitude for the following people who have invested their time for the bugs that are subject of this announcement: Chris Evans Solar Designer Alan Cox David Miller for spotting and fixing the problems as listed in the 2.2.19 release notes Chris Mason for fixing the reiserfs mmap/write race condition Sven Berkvens and Marc Olzheim for spotting the mmap/write race condition in FreeBSD drivers that affects reiserfs in Linux ______________________________________________________________________________ 3) standard appendix: 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 annoucements 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 . =============================================== ______________________________________________________________________________ The information in this advisory may be distributed or reproduced, provided that the advisory is not modified in any way. SuSE GmbH makes no warranties of any kind whatsoever with respect to the information contained in this security advisory. Type Bits/KeyID Date User ID pub 2048/3D25D3D9 1999/03/06 SuSE Security Team - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6.3i mQENAzbhLQQAAAEIAKAkXHe0lWRBXLpn38hMHy03F0I4Sszmoc8aaKJrhfhyMlOA BqvklPLE2f9UrI4Xc860gH79ZREwAgPt0pi6+SleNFLNcNFAuuHMLQOOsaMFatbz JR9i4m/lf6q929YROu5zB48rBAlcfTm+IBbijaEdnqpwGib45wE/Cfy6FAttBHQh 1Kp+r/jPbf1mYAvljUfHKuvbg8t2EIQz/5yGp+n5trn9pElfQO2cRBq8LFpf1l+U P7EKjFmlOq+Gs/fF98/dP3DfniSd78LQPq5vp8RL8nr/o2i7jkAQ33m4f1wOBWd+ cZovrKXYlXiR+Bf7m2hpZo+/sAzhd7LmAD0l09kABRG0JVN1U0UgU2VjdXJpdHkg VGVhbSA8c2VjdXJpdHlAc3VzZS5kZT6JARUDBRA24S1H5Fiyh7HKPEUBAVcOB/9b yHYji1/+4Xc2GhvXK0FSJN0MGgeXgW47yxDL7gmR4mNgjlIOUHZj0PEpVjWepOJ7 tQS3L9oP6cpj1Fj/XxuLbkp5VCQ61hpt54coQAvYrnT9rtWEGN+xmwejT1WmYmDJ xG+EGBXKr+XP69oIUl1E2JO3rXeklulgjqRKos4cdXKgyjWZ7CP9V9daRXDtje63 Om8gwSdU/nCvhdRIWp/Vwbf7Ia8iZr9OJ5YuQl0DBG4qmGDDrvImgPAFkYFzwlqo choXFQ9y0YVCV41DnR+GYhwl2qBd81T8aXhihEGPIgaw3g8gd8B5o6mPVgl+nJqI BkEYGBusiag2pS6qwznZiQEVAwUQNuEtBHey5gA9JdPZAQFtOAf+KVh939b0J94u v/kpg4xs1LthlhquhbHcKNoVTNspugiC3qMPyvSX4XcBr2PC0cVkS4Z9PY9iCfT+ x9WM96g39dAF+le2CCx7XISk9XXJ4ApEy5g4AuK7NYgAJd39PPbERgWnxjxir9g0 Ix30dS30bW39D+3NPU5Ho9TD/B7UDFvYT5AWHl3MGwo3a1RhTs6sfgL7yQ3U+mvq MkTExZb5mfN1FeaYKMopoI4VpzNVeGxQWIz67VjJHVyUlF20ekOz4kWVgsxkc8G2 saqZd6yv2EwqYTi8BDAduweP33KrQc4KDDommQNDOXxaKOeCoESIdM4p7Esdjq1o L0oixF12Cg== =pIeS - -----END PGP PUBLIC KEY BLOCK----- -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv iQEVAwUBOwPjCney5gA9JdPZAQHnowf/Z4oGIAWzSdnXcxhoUot4UABzH8X2rUfD 9caheLboumIR+gJ8XwuJzxkgl06wfZ6+4SF+WyKovEzJNYN2NjrZOtVYVukc/h9l txnJ5MQ0vtllge45eBGI5r+MZnfk5l107U/Az5/7hZuw7bUTZP991HCPHfnlUDAd YErqQ1KkSg2waTd5dqUjjSXGNjHP8dXG4RAwzqEXQ7PyQmVfwh6YQ0JpJLqXSKM/ Fx9sRaQXVX+Ujx7GI4TA/nPt7SIrLJhBKloV/En2tjHYcq6HiPiyO0a3jwD70wBf 9J3FYdPyWrarwKRqETBDfy+d7mWxgYmisPcZTeGgmK4ekakUSZfcEg== =uQx9 -----END PGP SIGNATURE-----