Bug 703972 – CVE-2011-1781 systemtap: divide by zero stack unwinding flaw

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Bug 703972 - (CVE-2011-1781) CVE-2011-1781 systemtap: divide by zero stack unwinding flaw

Summary:	CVE-2011-1781 systemtap: divide by zero stack unwinding flaw

Status:	CLOSED ERRATA

Aliases:	CVE-2011-1781

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	public=20110511,reported=20110505,sou...
Keywords:	Security

Depends On:	703979 703980
Blocks:
	Show dependency tree / graph

Reported:	2011-05-11 15:30 EDT by Josh Bressers
Modified:	2015-07-27 09:24 EDT (History)
CC List:	6 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2012-02-03 15:45:31 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2011:0842	normal	SHIPPED_LIVE	Moderate: systemtap security update	2011-05-31 10:04:42 EDT

Groups: None (edit)

Description Josh Bressers 2011-05-11 15:30:50 EDT

A flaw was discovered in systemtap's handling of DWARF expressions where it
did not guard against divide by zero when unwinding the stack.  This can
result in a kernel div-by-zero message and possible busywait during stap
module shutdown.  A div-by-zero could cause the kernel to panic and if the
kernel reboot on panic flag was set (panic_on_oops), it would cause the
system to reboot.

In order to trigger this flaw, an admin would have to enable unprivileged
mode. If an admin has enabled unprivileged mode, a normal user could use
this to crash the target machine.

A workaround is to disable unprivileged mode.

Comment 1 Josh Bressers 2011-05-11 15:32:57 EDT

This bug only affects systemtap versions 1.4 and above. We are rebasing systemtap to an affected version in Red Hat Enterprise Linux 6.1. This flaw will not be fixed before 6.1 GA.

Comment 3 Frank Ch. Eigler 2011-05-11 19:34:29 EDT

Fixed upstream:

http://sourceware.org/git/?p=systemtap.git;a=commit;h=fa2e3415185a28542d419a641ecd6cddd52e3cd9

Comment 4 Frank Ch. Eigler 2011-05-11 19:35:31 EDT

"If an admin has enabled unprivileged mode, a normal user could use
this to crash the target machine."

Not quite "normal" - the user would still have to be member of the "stapusr" group.

Comment 5 Tomas Hoger 2011-05-20 07:53:23 EDT

Public now via upstream commit mentioned in comment #3.

Comment 9 errata-xmlrpc 2011-05-31 10:04:51 EDT

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:0842 https://rhn.redhat.com/errata/RHSA-2011-0842.html

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