RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1372305 - glibc: fopencookie hardening
Summary: glibc: fopencookie hardening
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: glibc
Version: 7.3
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Florian Weimer
QA Contact: Sergey Kolosov
URL:
Whiteboard:
Depends On:
Blocks: 1372306 1372375 1473718
TreeView+ depends on / blocked
 
Reported: 2016-09-01 11:32 UTC by Florian Weimer
Modified: 2018-04-10 13:57 UTC (History)
6 users (show)

Fixed In Version: glibc-2.17-211.el7
Doc Type: Enhancement
Doc Text:
Feature: The fopencookie function stores the callback function pointers in a mangled form. Reason: These function pointers are a potential target for exploit writers because they reside on the heap, and execution could be redirect through them. Result: Now that they are mangled, it is more difficult to abuse them as part of exploits because an attacker would have to guess both the location of the pointers and the pointer guard value used for mangling.
Clone Of:
Environment:
Last Closed: 2018-04-10 13:56:38 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2018:0805 0 None None None 2018-04-10 13:57:56 UTC
Sourceware 20222 0 P2 RESOLVED fopencookie: Mangle function pointers 2020-02-14 08:31:25 UTC

Description Florian Weimer 2016-09-01 11:32:20 UTC 
Upstream implemented obfuscation for function pointers stored in stdio streams created with fopencookie:

commit 983fd5c41ab7e5a5c33922259ca1ac99b3b413f8
Author: Florian Weimer <fweimer>
Date:   Sat Jun 11 12:07:14 2016 +0200

    fopencookie: Mangle function pointers stored on the heap [BZ #20222]

This does not have ABI impact and is necessary to block libio-based code execution exploits (after vtable verification has been enabled).
Comment 9 errata-xmlrpc 2018-04-10 13:56:38 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
Note You need to log in before you can comment on or make changes to this bug.