Bug 1447556

Summary: glibc: malloc: check for chunk_size == next->prev->chunk_size in unlink
Product: Red Hat Enterprise Linux 7 Reporter: Florian Weimer <fweimer>
Component: glibcAssignee: DJ Delorie <dj>
Status: CLOSED ERRATA QA Contact: Sergey Kolosov <skolosov>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.4CC: ashankar, dj, fweimer, mcermak, mnewsome, pfrankli, skolosov
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: glibc-2.17-197.el7 Doc Type: Enhancement
Doc Text:
This patch adds an additional check for applications which change memory outside of the range allocated by malloc(), thus further hardening the malloc internals against both accidental and malicious overflows.
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-04-10 13:58:28 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: 1473718    

Description Florian Weimer 2017-05-03 08:02:45 UTC
We should backport this additional upstream hardening:

commit 17f487b7afa7cd6c316040f3e6c86dc96b2eec30
Author: DJ Delorie <dj>
Date:   Fri Mar 17 15:31:38 2017 -0400

    Further harden glibc malloc metadata against 1-byte overflows.
    
    Additional check for chunk_size == next->prev->chunk_size in unlink()
    
    2017-03-17  Chris Evans  <scarybeasts>
    
            * malloc/malloc.c (unlink): Add consistency check between size and
            next->prev->size, to further harden against 1-byte overflows.

This is on top of the hardening in bug 1326739.

Comment 5 errata-xmlrpc 2018-04-10 13:58:28 UTC
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://access.redhat.com/errata/RHSA-2018:0805