Bug 1289022 – VLAs not protected with -fstack-protector

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Bug 1289022 - VLAs not protected with -fstack-protector

Summary:	VLAs not protected with -fstack-protector

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	gcc (Show other bugs)
Sub Component:
Version:	7.3
Hardware:	Unspecified Unspecified

Priority	unspecified Severity unspecified
Target Milestone:	rc
Target Release:	7.3
Assigned To:	Jakub Jelinek
QA Contact:	Michael Petlan
Docs Contact:	Tomas Capek

URL:
Whiteboard:
Keywords:

Depends On:
Blocks:	1297579 1313485
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Reported:	2015-12-07 04:17 EST by Jakub Jelinek
Modified:	2017-02-16 08:38 EST (History)
CC List:	4 users (show)

See Also:
Fixed In Version:	gcc-4.8.5-6.el7
Doc Type:	Bug Fix
Doc Text:	Better stack protection in GCC Prior to this update, GCC stack protection did not work for functions that only contained variable-length arrays and no other (or only very small) arrays. Consequently, a buffer overflow error could occur undetected. This bug has been fixed and the compiler is now able to instrument even such functions.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2016-11-04 02:27:17 EDT
Type:	Bug
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
GNU Compiler Collection	68680	None	None	None	Never
Red Hat Product Errata	RHBA-2016:2433	normal	SHIPPED_LIVE	gcc bug fix and enhancement update	2016-11-03 10:01:11 EDT

Groups: None (edit)

Description Jakub Jelinek 2015-12-07 04:17:07 EST

In GCC 4.7+, gcc mistakenly does not stack protect functions that contain just a variable length array and no other (or only very small) arrays.
See http://gcc.gnu.org/PR68680 for details, just use -fstack-protector instead of -fstack-protector-strong.

E.g. -O2 -fstack-protector:

int process(char *);

int
uses_vla(unsigned long sz)
{
  char buf[sz];
  return process(buf);
}

Comment 3 Michael Petlan 2016-07-25 05:48:51 EDT

test fails with gcc-4.8.5-4.el7
test passes for gcc-4.8.5-9.el7

VERIFIED

Comment 5 errata-xmlrpc 2016-11-04 02:27:17 EDT

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2433.html

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