From Fedora Project Wiki
< Changes
(Fix categories) |
No edit summary |
||
| Line 106: | Line 106: | ||
* On systems which support memory protection keys, lazy binding now uses a read-only GOT. | * On systems which support memory protection keys, lazy binding now uses a read-only GOT. | ||
[[Category: | [[Category:ChangeAnnounced]] | ||
<!-- When your change proposal page is completed and ready for review and announcement --> | <!-- When your change proposal page is completed and ready for review and announcement --> | ||
<!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler --> | <!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler --> | ||
Revision as of 13:29, 4 January 2018
Hardening Flags Updates for Fedora 28
Summary
This system-wide change covers changes to the hardening flags in Fedora 28.
Owner
- Name: Florian Weimer
- Email: fweimer@redhat.com
- Release notes owner:
Current status
- Targeted release: Fedora 28
- Last updated: 2018-01-04
- Tracker bug: <will be assigned by the Wrangler>
Detailed Description
- Compile all binaries with stack clash protection (
-fstack-clash-protection). As a result, all stack overflows (i.e., situations where the allocated stack is completely exhausted) will reliably result in crashes. - Enable C++ standard library hardening with
-D_GLIBCXX_ASSERTIONS. This turns on cheap range checks for C++ arrays, vectors, and strings. - Enable control flow protection on x86-64 using
-fcf-protection=full -mcet. - Enable
.got.pltisolation in binutils, to support a read-only GOT with lazy binding on systems which provide support for memory protection keys.
Benefit to Fedora
Fedora will benefit from additional security hardening provided by the GNU toolchain.
Scope
- Proposal owners: Propose changes to
redhat-rpm-configto implement the new flags. - Other developers: The
redhat-rpm-configchanges need to be merged. For packages which bypass the RPM compiler flags injection mechanism, developers need to manually implement the new flags.
- Release engineering: #7220 (a check of an impact with Release Engineering is needed)
- Policies and guidelines: N/A (not needed for this Change; covered by the existing Packaging Guidelines)
- Trademark approval: N/A (not needed for this Change)
Upgrade/compatibility impact
The C++ standard library hardening may detect some invalid out-of-bounds access which have gone unnoticed before.
How To Test
Changes/Annobin will be used to track the implementation of the hardening flags.
User Experience
There will not be any user-visible differences.
Dependencies
Testing depends on Changes/Annobin.
Contingency Plan
- Contingency mechanism: Revert change to
redhat-rpm-config, or make them specific to supported architectures only.- An ABI-compliant
-fstack-clash-protectionimplementation has not yet been demonstrated for 32-bit ARM (armhfp). It may be necessary to disable the hardening there.
- An ABI-compliant
- Contingency deadline: final mass rebuild
- Blocks release? no
- Blocks product? N/A
Documentation
Release Notes
Fedora 28 has been built with updated hardening flags, as provided by the GNU toolchain. Compared to previous releases, the following changes have been made to the way programs are built:
- Stack clash protection is enabled.
- Lightweight assertions have been switched on in the C++ standard run-time library.
- On x86-64, binaries have been built in a way that they will support Control Flow Enforcement Technology (CET) in the future.
- On systems which support memory protection keys, lazy binding now uses a read-only GOT.