RedHat: gpm vulnerability
Posted by LinuxSecurity.com Team   
RedHat Linux Multiple security problems and a gpmctl vulnerability exists.
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                   Red Hat, Inc. Security Advisory

Synopsis:          gpm security flaws have been addressed
Advisory ID:       RHSA-2000:045-01
Issue date:        2000-07-26
Updated on:        2000-07-26
Product:           Red Hat Linux
Keywords:          gpm, denial of service, /dev/gpmctl, gpm-root, setgid
Cross references:  RHSA-2000:044
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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. 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

3. 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.

4. 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.

5. Bug IDs fixed  (http://bugzilla.Red Hat.com/bugzilla for more info):

11607 - Newest gpm RPM package will not install


6. RPMs required:

Red Hat Linux 5.2:

sparc: 
ftp://updates.Red Hat.com/5.2/sparc/gpm-1.19.3-0.5.x.sparc.rpm

alpha: 
ftp://updates.Red Hat.com/5.2/alpha/gpm-1.19.3-0.5.x.alpha.rpm

i386: 
ftp://updates.Red Hat.com/5.2/i386/gpm-1.19.3-0.5.x.i386.rpm

sources: 
ftp://updates.Red Hat.com/5.2/SRPMS/gpm-1.19.3-0.5.x.src.rpm

Red Hat Linux 6.2:

sparc: 
ftp://updates.Red Hat.com/6.2/sparc/gpm-1.19.3-0.6.x.sparc.rpm

i386: 
ftp://updates.Red Hat.com/6.2/i386/gpm-1.19.3-0.6.x.i386.rpm

alpha: 
ftp://updates.Red Hat.com/6.2/alpha/gpm-1.19.3-0.6.x.alpha.rpm

sources: 
ftp://updates.Red Hat.com/6.2/SRPMS/gpm-1.19.3-0.6.x.src.rpm

7. Verification:

MD5 sum                           Package Name
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7e14aa2b98ababfe815b292ff8439b50  5.2/SRPMS/gpm-1.19.3-0.5.x.src.rpm
668c1dd35c9e28cd54c34aed0126afe9  5.2/alpha/gpm-1.19.3-0.5.x.alpha.rpm
6e5ae7e9d4f552978d4821fe5e06e27b  5.2/i386/gpm-1.19.3-0.5.x.i386.rpm
13be2dda7373cbb90567b11dca1e8a76  5.2/sparc/gpm-1.19.3-0.5.x.sparc.rpm
8205248615a5e249e3612753ec7d7c08  6.2/SRPMS/gpm-1.19.3-0.6.x.src.rpm
1750a3ba1ff2094e9e77bcaac8ece826  6.2/alpha/gpm-1.19.3-0.6.x.alpha.rpm
0dd38c9d324a9e82ab8aceb75394a94e  6.2/i386/gpm-1.19.3-0.6.x.i386.rpm
274dfea2fffb8dc6785686409ba3f37a  6.2/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.Red Hat.com/corp/contact.html

You can verify each package with the following command:
    rpm --checksig  

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 

8. References:
 
100000@csibe.fazekas.hu'>http://www.securityfocus.com/templates/archive.pike?list=1&date=2000-03-22&msg=Pine.LNX.4.21.0003231428110.13143-100000@csibe.fazekas.hu
 
200000@apollo.aci.com.pl'>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


Copyright(c) 2000 Red Hat, Inc.

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