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Bug 491266

Summary: kernel should be built with -fwrapv [rhel-5.4]
Product: Red Hat Enterprise Linux 5 Reporter: Eugene Teo (Security Response) <eteo>
Component: kernelAssignee: Don Zickus <dzickus>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: high Docs Contact:
Priority: urgent    
Version: 5.4CC: anton, dhoward, dzickus, emcnabb, jpirko, jplans, jskrabal, lwang, mgahagan, security-response-team
Target Milestone: rcKeywords: ZStream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-09-02 04:06:01 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Bug Depends On:    
Bug Blocks: 501751    
Attachments:
Description Flags
Upstream patch none

Description Eugene Teo (Security Response) 2009-03-20 02:33:07 EDT
Description of problem:
Add '-fwrapv' to gcc CFLAGS. This makes sure that gcc doesn't try to optimize
away wrapping arithmetic, which the kernel occasionally uses for overflow
testing, ie things like

if (ptr + offset < ptr)

which technically is undefined for non-unsigned types. See

http://bugzilla.kernel.org/show_bug.cgi?id=12597

for details.

Not all versions of gcc support it, so we need to make it conditional (it looks
like it was introduced in gcc-3.4).
Comment 7 RHEL Product and Program Management 2009-05-18 23:49:27 EDT
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.
Comment 9 Don Zickus 2009-05-21 11:36:35 EDT
in kernel-2.6.18-150.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.
Comment 12 Eugene Teo (Security Response) 2009-07-20 04:02:25 EDT
See bug 512650. Use -fno-strict-overflow instead of -fwrapv.
Comment 14 errata-xmlrpc 2009-09-02 04:06:01 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2009-1243.html