AUSCERT External Security Bulletin Redistribution
                      ESB-1999.164 -- RHSA-1999:041-03
                       File access problems in lpr/lpd
                               26 October 1999


Red Hat, Inc. has released the following advisory concerning file access
checking vulnerabilities in lpr/lpd.

These vulnerabilities may be exploited by users to print files for which
they do not have permission to read.  All Red Hat versions and platforms
are affected by these vulnerabilities.  Red Hat have issued patches which
correct these vulnerabilities.

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		   Red Hat, Inc. Security Advisory

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:	
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Revision History:
 1999-10-19: New packages, to fix a remote printing bug.
             Add note about local printing fix for Red Hat
	     Linux 6.1.
 1999-10-25: New packages, to fix problems introduced by
	     the security fix.

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. Bug IDs fixed (http://developer.redhat.com/bugzilla for more info):

5122 5540 5697 5832 5835 5903 5949

3. Relevant releases/architectures:

Red Hat Linux 4.x, all architectures
Red Hat Linux 5.x, all architectures
Red Hat Linux 6.x, all architectures

4. Obsoleted by:

5. Conflicts with:

6. RPMs required:

Red Hat Linux 4.x:




Source packages:

Red Hat Linux 5.x:




Source packages:

Red Hat Linux 6.x:




Source packages:

7. 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

Also, various bugs in remote printing that were present
in the lpd released with Red Hat Linux 6.1 have been fixed.

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

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.

The original security patch broke some aspects of printing. New
errata RPMs are available which should fix the problem.

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
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3ac16788d027447679cf6bf5e6483574  lpr-0.46-0.4.2.src.rpm
78b9f5c8538d382c24fbe303c1e05858  lpr-0.46-0.4.2.alpha.rpm
daffbab440b7dbabd233904a75e3bb82  lpr-0.46-0.4.2.i386.rpm
def0c894a62875e809b5693c09393931  lpr-0.46-0.4.2.sparc.rpm

91635732bdf133068543f18887b4eb9d  lpr-0.46-0.5.2.src.rpm
cd5575ca2c159f30beff740709699992  lpr-0.46-0.5.2.alpha.rpm
756d445db7803b0db3a5f8b19dca0702  lpr-0.46-0.5.2.i386.rpm
c064b331ac84d67714fe46913b3669c5  lpr-0.46-0.5.2.sparc.rpm

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 signed with GnuPG by Red Hat Inc. for security. Our key
is available at:
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.

10. References:

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