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Gentoo Linux Security Advisory                           GLSA 202210-33
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                                           https://security.gentoo.org/
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 Severity: Normal
    Title: Libtirpc: Denial of Service
     Date: October 31, 2022
     Bugs: #859634
       ID: 202210-33

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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
    -------------------------------------------------------------------
  1  net-libs/libtirpc          < 1.3.2                      >= 1.3.2

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
==========

[ 1 ] CVE-2021-46828
      https://nvd.nist.gov/vuln/detail/CVE-2021-46828

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

 https://security.gentoo.org/glsa/202210-33

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.

License
=======

Copyright 2022 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

https://creativecommons.org/licenses/by-sa/2.5