Bug 715436 (CVE-2011-2484)

Summary: CVE-2011-2484 kernel: taskstats: duplicate entries in listener mode can lead to DoS
Product: [Other] Security Response Reporter: Petr Matousek <pmatouse>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: jmarchan
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2015-07-29 12:48:59 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 715447, 715448, 715449, 715450, 715451    
Bug Blocks:    

Description Petr Matousek 2011-06-22 21:55:41 UTC 
Currently a single process may register exit handlers unlimited times. It may lead to a bloated listeners chain and very slow process terminations. E.g. after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of kernel memory is stolen for the handlers chain and "time id" shows 2-7 seconds instead of normal 0.003.  It makes it possible to exhaust all kernel memory and to eat much of CPU time by triggerring numerous exits on a single CPU ie it makes it possible for unprivileged user eat kernel memory and CPU without triggering OOM killer.

Introduced in f9fd8914c1acca0d98b69d831b128d5b52f03c51.

References:
http://seclists.org/oss-sec/2011/q2/664
http://lists.openwall.net/linux-kernel/2011/06/16/605

Acknowledgements:                                                               

Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting this issue.
Comment 3 Eugene Teo (Security Response) 2011-06-29 06:04:54 UTC 
Upstream commit:
http://git.kernel.org/linus/26c4caea9d697043cc5a458b96411b86d7f6babd
Comment 4 Eugene Teo (Security Response) 2011-06-29 08:12:45 UTC 
Statement:

This issue did not affect the versions of Linux kernel as shipped with Red Hat
Enterprise Linux 4 as it did not provide support for the Taskstats interface. This was fixed in Red Hat Enterprise Linux 5, 6, and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1386.html, https://rhn.redhat.com/errata/RHSA-2011-1350.html and https://rhn.redhat.com/errata/RHSA-2011-1253.html.
Comment 7 errata-xmlrpc 2011-09-12 19:45:44 UTC 
This issue has been addressed in following products:

  MRG for RHEL-6 v.2

Via RHSA-2011:1253 https://rhn.redhat.com/errata/RHSA-2011-1253.html
Comment 8 errata-xmlrpc 2011-10-05 21:47:47 UTC 
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:1350 https://rhn.redhat.com/errata/RHSA-2011-1350.html
Comment 9 errata-xmlrpc 2011-10-20 17:28:48 UTC 
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2011:1386 https://rhn.redhat.com/errata/RHSA-2011-1386.html