| Summary: | glibc: fopencookie hardening | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Florian Weimer <fweimer> |
| Component: | glibc | Assignee: | Florian Weimer <fweimer> |
| Status: | CLOSED ERRATA | QA Contact: | Sergey Kolosov <skolosov> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 7.3 | CC: | ashankar, codonell, fweimer, mnewsome, pfrankli, skolosov |
| Target Milestone: | rc | Keywords: | Patch |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| 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.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2018-04-10 13:56:38 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: | |
| Bug Depends On: | |||
| Bug Blocks: | 1372306, 1372375, 1473718 | ||
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 |
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).