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Bug 716842 - (CVE-2011-2494) CVE-2011-2494 kernel: taskstats io infoleak
CVE-2011-2494 kernel: taskstats io infoleak
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
low Severity low
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Assigned To: Red Hat Product Security
: Security
Depends On: 716845 716846 716847 716848 716849 761355
Blocks: 716823
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Reported: 2011-06-27 05:04 EDT by Eugene Teo (Security Response)
Modified: 2015-07-31 02:42 EDT (History)
18 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2012-05-04 03:06:16 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description Eugene Teo (Security Response) 2011-06-27 05:04:27 EDT
taskstats information may be used for gathering private information.  E.g. for openssh and vsftpd daemons read_characters/write_characters may be used to learn the precise password length.  Restrict it to processes being able to ptrace the target process.  For TASKSTATS_CMD_ATTR_REGISTER_CPUMASK the fix is euid check instead of a ptrace check as the handler is processed in the context of the target process, not the listener process'.  When ptrace_task_may_access_current() is introduced, it should be used instead of euid check.  Currently there is a small race when a process temporarily changes its euid (e.g. to access user's files), until the process sets euid back user's processes may gather privileged process' statistics.

taskstats authorized_keys presence infoleak PoC

[0/2] restrict statistics information to user
[1/2] proc: restrict access to /proc/PID/io (CVE-2011-2495)
[2/2] taskstats: restrict access to user (CVE-2011-2494)
Linus suggested returning accounting information at a 1k granularity instead.


Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting this issue.
Comment 3 Eugene Teo (Security Response) 2011-06-27 05:18:29 EDT

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 has been addressed in Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise MRG via,, and
Comment 4 Eugene Teo (Security Response) 2011-06-29 02:12:21 EDT
(In reply to comment #0)
> [2/2] taskstats: restrict access to user (CVE-2011-2494)
Comment 5 Petr Matousek 2011-09-21 13:17:11 EDT
(In reply to comment #4)
> (In reply to comment #0)
> [...]
> > [2/2] taskstats: restrict access to user (CVE-2011-2494)
> >

Upstream patch:
Comment 6 errata-xmlrpc 2011-11-22 11:49:35 EST
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:1465
Comment 7 errata-xmlrpc 2011-11-29 09:35:56 EST
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2011:1479
Comment 9 errata-xmlrpc 2012-01-10 15:15:44 EST
This issue has been addressed in following products:

  MRG for RHEL-6 v.2

Via RHSA-2012:0010

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