RH6.1: lpr (RHSA-1999:041-03)
Posted by LinuxSecurity.com Team   
RedHat Linux There are potential problems with file access checking in the lpr and lpd programs. These could allow users to potentially print files they do not have access to. Also, there are bugs in remote printing in the lpd that shipped with Red Hat Linux 6.1.
 
Red Hat, Inc. Security Advisory
Package lpr

Synopsis File access problems in lpr/lpd

Advisory ID RHSA-1999:041-03

Issue Date 1999-10-17

Updated on 1999-10-25

Keywords lpr lpd permissions

Cross references N/A

Revision History:
1999-10-25: New packages, to fix problems introduced by the security fix.

1999-10-19: New packages, to fix a remote printing bug. Add note about local printing fix for Red Hat Linux 6.1.

1. Topic:
There are potential problems with file access checking in the lpr and lpd programs. These could allow users to potentially print files they do not have access to. Also, there are bugs in remote printing in the lpd that shipped with Red Hat Linux 6.1.

2. Problem description:
There are two problems in the lpr and lpd programs. By exploiting a race between the access check and the actual file opening, it is potentially possible to have lpr read a file as root that the user does not have access to. Also, the lpd program would blindly open queue files as root; by use of the '-s' flag to lpr, it was possible to have lpd print files that the user could not access.

Thanks go to Tymm Twillman for pointing out these vulnerabilities.

(1999-10-19)
Another problem with remote printing was fixed in lpr-0.44. If you are experiencing problems with remote printing in the previous errata update, it is recommended that you upgrade. There are no known security issues with the previous errata packages.

If you are experiencing problems with local printing in Red Hat Linux 6.1, make sure that you have:

alias parport_lowlevel parport_pc

in your /etc/conf.modules file.

(1999-10-25)
The original security patch broke some aspects of printing. New errata RPMs are available which should fix the problem.

3. Bug IDs fixed: (see bugzilla for more information)
5122 5540 5697 5832 5835 5903 5949

4. Relevant releases/architectures:
Red Hat Linux 6.1, all architectures

5. Obsoleted by:
None

6. Conflicts with:
None

7. RPMs required:

Intel:

ftp://updates.Red Hat.com/6.1/i386/

lpr-0.46- 1.i386.rpm

Alpha:

ftp://updates.Red Hat.com/6.0/alpha

lpr-0.46- 1.alpha.rpm

SPARC:

ftp://updates.Red Hat.com/6.1/sparc

lpr-0.46- 1.sparc.rpm

Source:

ftp://updates.Red Hat.com/6.1/SRPMS

lpr-0.46- 1.src.rpm

Architecture neutral:

ftp://updates.Red Hat.com/6.1/noarch/

8. Solution:
For each RPM for your particular architecture, run:

rpm -Uvh filename

where filename is the name of the RPM.

9. Verification:


 MD5 sum                           Package Name

 -------------------------------------------------------------------------
03c996550636cbe4ca0a9fc853f969b6  lpr-0.46-1.src.rpm
30089f82ecf8e8a89565c5bba361697d  lpr-0.46-1.alpha.rpm
a01c0b9278c2c9ffb4bb6450703fc124  lpr-0.46-1.i386.rpm
41a1ef221a15446ed46b54092d7c14ca  lpr-0.46-1.sparc.rpm


 
These packages are GPG signed by Red Hat Inc. for security. Our key is available at: http://www.Red Hat.com/corp/contac t.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

10. References: