GLSA 202210-33: Libtirpc: Denial of Service

http://security.gentoo.org/

Severity:	normal
Title:	Libtirpc: Denial of Service
Date:	10/31/2022
Bugs:	#859634
ID:	202210-33

Synopsis

A vulnerability has been discovered in Libtirpc which could result in denial of service.

Background

Libtirpc is a port of Sun's Transport-Independent RPC library to Linux.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
net-libs/libtirpc	< 1.3.2	>= 1.3.2	All supported architectures

Description

Currently svc_run does not handle poll timeout and rendezvous_request does not handle EMFILE error returned from accept(2 as it used to. These two missing functionality were removed by commit b2c9430f46c4. The effect of not handling poll timeout allows idle TCP conections to remain ESTABLISHED indefinitely. When the number of connections reaches the limit of the open file descriptors (ulimit -n) then accept(2) fails with EMFILE. Since there is no handling of EMFILE error this causes svc_run() to get in a tight loop calling accept(2). This resulting in the RPC service of svc_run is being down, it's no longer able to service any requests. Due to a lack of handling of certain error cases, connections to Libtirpc could remain ESTABLISHED indefinitely.

Impact

Denial of service can be achieved via establishing enough connections to Libtirpc to reach the limit of open file descriptors for the process.

Workaround

There is no known workaround at this time.

Resolution

All Libtirpc users should upgrade to the latest version:

          # emerge --sync
          # emerge --ask --oneshot --verbose ">=net-libs/libtirpc-1.3.2"

References

CVE-2021-46828

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-202210-33.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.