Bug 2072758

Summary:	gcc -Wbidirectional vs -Wbidi-chars discrepancy
Product:	Red Hat Enterprise Linux 9	Reporter:	benh <benh>
Component:	gcc	Assignee:	Marek Polacek <mpolacek>
gcc sub component:	system-version	QA Contact:	Václav Kadlčík <vkadlcik>
Status:	CLOSED NOTABUG	Docs Contact:	Petr Hybl <phybl>
Severity:	unspecified
Priority:	unspecified	CC:	ahajkova, bstinson, fweimer, gfialova, jakub, jwboyer, mpolacek, ohudlick, phybl, sipoyare, tumeya
Version:	CentOS Stream	Keywords:	Bugfix, Triaged
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Cause: Divergence between RHEL 9 gcc and upstream gcc. Consequence: Confusing for users. Fix: Make RHEL 9 gcc accept both -Wbidirectional and -Wbidi-chars Result: Less confusion	Story Points:	---
Clone Of:
Clones:	2072762 (view as bug list)		Environment:
Last Closed:	2022-04-20 17:38:42 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2072762

Description benh@amazon.com 2022-04-06 22:06:06 UTC

Description of problem:

To address CVE-2021-42574, RHEL8/CentOS8 implements a gcc patch which adds the -Wbidirectional option. This is also documented in various RH advisories.

This is unfortunately different from upstream gcc which named the option -Wbidi-chars instead.

From what I can see of the available source code, RHEL9/CentOS9 backported to gcc11 the "upstream" variant.

This can/will cause a discrepancy between RHEL8 and RHEL9 for customers and between RHEL and other distributions.

Would it be possible to amend the patches in the backports to support both variants ?

Version-Release number of selected component (if applicable):

I've verified the git repos of c8s and c9, but from the published advisories, this also affects the various devtoolsets.

I also noticed gcc has some followup fixes/updates for that code that weren't backported.

Comment 1 Marek Polacek 2022-04-06 22:11:47 UTC

Thanks for the report.  As I mentioned in the email, I would like to add an alias so that RHEL9 gcc groks both -Wbidirectional and -Wbidi-chars.

I think we want a clone for RHEL 8 gcc too.  But I don't see how we'd fix this in DTS/GTS at this point.

Comment 2 Marek Polacek 2022-04-20 17:38:42 UTC

Previously, I didn't realize that the newest versions of RHEL 8 gcc, DTS 11.1 gcc, GTS 11.1 gcc, and RHEL 9 gcc all *already* use -Wbidi-chars.
So I no longer think that the aliases are necessary, therefore I'm going to close this BZ.

Comment 3 benh@amazon.com 2022-04-20 21:40:01 UTC

My fault indeed. I was looking at centos c8 and not c8s...