1. Topic:
gpm as shipped in Red Hat Linux 5.2 and 6.x contains a number of
security problems. Additionally, a denial of service attack via
/dev/gpmctl is possible.
2. Problem description:
Two problems exist in gpm, the program used to enable mouse
control on the console when not using X Windows:
1. gpm did not perform adequate checking of setgid return values
in the gpm-root helper program. This resulted in an avenue of
attack where local users could execute arbitrary commands with
elevated group priviledges.
2. /dev/gpmctl was writable by users who were not on the console.
A user could perform a local denial of service attack by flooding
the socket.
The security issue has been addressed on 5.2 and 6.x.
For 6.x, the /dev/gpmctl ownership issue was addressed via the
pam_console helper mechanism. This pam module makes devices
which need to be accessible via console users owned by them and
no one else. See RHSA-2000:044 for more information on this
update.
On 5.2, there is no control of console devices available via pam,
so we have disabled access to /dev/gpmctl by default.
3. Bug IDs fixed: (see bugzilla for more information)
11607 - Newest gpm RPM package will not install
4. Relevant releases/architectures:
Red Hat Linux 5.2 - i386, alpha, sparc
Red Hat Linux 6.0 - i386, alpha, sparc
Red Hat Linux 6.1 - i386, alpha, sparc
Red Hat Linux 6.2 - i386, alpha, sparc
5. RPMs required:
Red Hat Linux 5.2:
sparc:
ftp://updates.redhat.com/5.2/en/os/sparc/gpm-1.19.3-0.5.x.sparc.rpm
alpha:
ftp://updates.redhat.com/5.2/en/os/alpha/gpm-1.19.3-0.5.x.alpha.rpm
i386:
ftp://updates.redhat.com/5.2/en/os/i386/gpm-1.19.3-0.5.x.i386.rpm
sources:
ftp://updates.redhat.com/5.2/en/os/SRPMS/gpm-1.19.3-0.5.x.src.rpm
Red Hat Linux 6.2:
sparc:
ftp://updates.redhat.com/6.2/en/os/sparc/gpm-1.19.3-0.6.x.sparc.rpm
i386:
ftp://updates.redhat.com/6.2/en/os/i386/gpm-1.19.3-0.6.x.i386.rpm
alpha:
ftp://updates.redhat.com/6.2/en/os/alpha/gpm-1.19.3-0.6.x.alpha.rpm
sources:
ftp://updates.redhat.com/6.2/en/os/SRPMS/gpm-1.19.3-0.6.x.src.rpm
6. Solution:
For each RPM for your particular architecture, run:
rpm -Fvh [filename]
where filename is the name of the RPM.
For 6.x systems, you must upgrade your pam to the version
discussed in RHSA-2000:044 to achieve protection from the denial
of service attack.
For Red Hat Linux 5.2, if you use gpm's "repeater" functionality
for X Windows, you will need to reenable access to group/other
users of /dev/gpmctl with the chown command. Red Hat Linux does
not make use of this functionality by default, and we do not
recommend taking this action for the reasons explained above.
7. Verification:
MD5 sum Package Name
-------------------------------------------------------------------------
7e14aa2b98ababfe815b292ff8439b50 5.2/en/os/SRPMS/gpm-1.19.3-0.5.x.src.rpm
668c1dd35c9e28cd54c34aed0126afe9 5.2/en/os/alpha/gpm-1.19.3-0.5.x.alpha.rpm
6e5ae7e9d4f552978d4821fe5e06e27b 5.2/en/os/i386/gpm-1.19.3-0.5.x.i386.rpm
13be2dda7373cbb90567b11dca1e8a76 5.2/en/os/sparc/gpm-1.19.3-0.5.x.sparc.rpm
8205248615a5e249e3612753ec7d7c08 6.2/en/os/SRPMS/gpm-1.19.3-0.6.x.src.rpm
1750a3ba1ff2094e9e77bcaac8ece826 6.2/en/os/alpha/gpm-1.19.3-0.6.x.alpha.rpm
0dd38c9d324a9e82ab8aceb75394a94e 6.2/en/os/i386/gpm-1.19.3-0.6.x.i386.rpm
274dfea2fffb8dc6785686409ba3f37a 6.2/en/os/sparc/gpm-1.19.3-0.6.x.sparc.rpm
These packages are GPG signed by Red Hat, Inc. for security. Our key
is available at:
http://www.redhat.com/about/contact.html
You can verify each package with the following command:
rpm --checksig filename
If you only wish to verify that each package has not been corrupted or
tampered with, examine only the md5sum with the following command:
rpm --checksig --nogpg filename
Note that you need RPM >= 3.0 to check GnuPG keys.
8. References:
http://www.securityfocus.com/templates/archive.pike?list=1&date=2000-03-22&msg=Pine.LNX.4.21.0003231428110.13143-100000@csibe.fazekas.hu
http://www.securityfocus.com/templates/archive.pike?list=1&date=2000-06-15&msg=Pine.LNX.4.10.10006201453090.1812-200000@apollo.aci.com.pl
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