-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On Mon, 2020-05-18 at 15:36 -0400, Ben Cotton wrote: > https://fedoraproject.org/wiki/Changes/Aarch64_PointerAuthentication > > == Summary == > Arm Pointer Authentication (PAC) is a method of hardening code from > Return Oriented Programming (ROP) attacks. It uses a tag in a pointer > to sign and verify pointers. Branch Target Identification (BTI) is > another code hardening method, where the branch/jump target is > identified with a special landing pad instruction. Outside of some > system support in glibc+kernel, packages gain the additional > hardening > by compiling with the -mbranch-protection= flag available in recent > versions of GCC. In particular -mbranch-protection=standard enables > both BTI and PAC, with backwards compatible to armv8.0 code sequences > that activate on v8.3 (PAC) & v8.5 (BTI) enabled Arm machines. Is there some noticeable performance drop or anything like that? > == Owner == > * Name: [[User:jlinton| Jeremy Linton]] & ARM SIG > * Email: jeremy.linton@xxxxxxx > > > == Benefit to Fedora == > > PAC & BTI are code hardening features, they should serve to make > fedora more resistant to a couple further classes of runtime attacks. > By enabling this early, fedora is once again proven to be at the > leading edge of security and linux development. If everything works > as > planned, this change will be invisible to the end user, except in > cases where the applications will trap behaviour that appears to be > caused by exploit attempts. > > == Scope == > * Proposal owners: > Work with individual package maintainers in the case of build > failures > or runtime exceptions. In the latter case there are two > possibilities. > First on v8.0 hardware, which is currently the most common, the > additional instruction sequences are treated as NOP's and should be > completely ignored by the hardware. It may be possible on v8.3/8.5 > hardware that PAC or BTI may need additional tweaks for hand written > assembly which interacts with PAC/BTI enabled code. It would be nice if you would specify which exact flags and where you will add them, so that it would be easy to see which people we need to get on board for this change. > * Other developers: > Assure their packages continue to compile and pass > unit/integration/etc tests on v8.0 hardware. Continue to monitor > runtime problems on v8.3+ for bugs, vs exploit attempts. > > * Release engineering: (pending) > * Policies and guidelines: > At the moment, nothing needs to be changed as this should propagate > as > the default set of RPM build flags. > * Trademark approval: N/A (not needed for this Change) > > > == Upgrade/compatibility impact == > If everything works as planned, this should be transparent to the end > user. > > == How To Test == > Testing falls into two categories. Assuring that the packages > continue > to work on existing arm v8.0 hardware without PAC, and testing on > PAC+BTI enabled hardware. For the most part the expectation from the > fedora community is that package maintainers assure their packages > continue to work on existing systems. PAC+ hardware will be in > limited > supply during the F33 development cycle, so the expectation is that > owners of that hardware will perform more complete systemwide testing > and report any defects found against the packages in question along > with fixes or hardware access. > > == User Experience == > (not supplied) > > == Dependencies == > There are various gcc and kernel related changes which have already > landed, but there continue to be a few cleanup patches trickling into > the toolchain/compiler as problems are discovered. > > == Contingency Plan == > * Contingency mechanism: (What to do? Who will do it?) > Build affected packages with explicit compiler flags disabling the > feature. Worse case the top level rpm macros reversion, and a rebuild > of effected packages. > > Contingency deadline: Beta target. > * Blocks release? No, except for major functionality loss due to core > package bug. > * Blocks product? No > > == Documentation == > Arm pointer authentication is a technology designed to make software > more robust by providing hardware assistance for code hardening. It > protects pointers by cryptographically signing them and verifying > their signatures when used, thereby mitigating certain attack > vectors. > Core support is provided to applications and libraries transparently > via kernel and toolchain changes to generate hardended code. Branch > Target identification, similarly provides landing pads, to harden > code > paths by restricting the processor from jumping into unexpected parts > of a function. > > Further reference: > * > https://developer.arm.com/architectures/learn-the-architecture/providing-protection-for-complex-software/return-oriented-programming > * > https://www.qualcomm.com/media/documents/files/whitepaper-pointer-authentication-on-armv8-3.pdf > * > https://www.usenix.org/system/files/sec19fall_liljestrand_prepub.pdf > * > https://events.static.linuxfound.org/sites/events/files/slides/slides_23.pdf > * https://lwn.net/Articles/789370/ > > -- > Ben Cotton > He / Him / His > Senior Program Manager, Fedora & CentOS Stream > Red Hat > TZ=America/Indiana/Indianapolis > _______________________________________________ > devel-announce mailing list -- devel-announce@xxxxxxxxxxxxxxxxxxxxxxx > To unsubscribe send an email to > devel-announce-leave@xxxxxxxxxxxxxxxxxxxxxxx > Fedora Code of Conduct: > https://docs.fedoraproject.org/en-US/project/code-of-conduct/ > List Guidelines: > https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: > https://lists.fedoraproject.org/archives/list/devel-announce@xxxxxxxxxxxxxxxxxxxxxxx - -- Igor Raits <ignatenkobrain@xxxxxxxxxxxxxxxxx> -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEcwgJ58gsbV5f5dMcEV1auJxcHh4FAl7EMcAACgkQEV1auJxc Hh430hAAuHRfXdDLdttuMU0jXfoVY7e+SyQIrw7c7AQh8NYseexlwjHb0gYGXcgI q21jW3KA5V86PIl+WI31jSf2bttwHkAw2NRYb42wU+lKk4e6Jy1J1NNNY0Wp7bSs bMu9C4+GjKh1JDxDBYPjnBtIGj0BwNMnEB/XPe4K/DZpwVDKhRZNcNWBGtmKjxbk lEs4zuzGBq+GOWQgpHmrCuUtgXmTOwovirIdnNW7qNs7EWwBo5oytb9Q6CUIE28A PfV5eRTJa1m1O7clNAe+2K3xGXuQ6k5OPmR/vZbZ3JqzsKUhh2UPLxoO7LIEmtlc C424ErAAxQd9Eop7eUrUA3KSr+6AFzW4fUCLnBYuTB9Hrwe3wl4smtwy8WfsiiTS przpZjNWDTGsxltIL3MWZFX09dxWq4jmy8aYaG7X5LHqMv/Mb5tDMrGXn0B0fczm sTOoNebE/TLkGLDoloOcsYBIXuSEOFlfHAnLECKZU4N2ZZEZeROjOWW6QI8w7Fng +XMJCQqih8NHc9eVxNWI5P089QLsBiL8xcnUyHaOAf8zx4K+1JsWiynLdjbjxvcu csUgWl/Ih894JN12EmuJyy0BxV/X0E/13SepMfieTte+fZqS2OAlykJWqx9aSkY2 5ameSrWfQ14zqAUGGn4ZkQXnh3N0ADPECDablEfYl2yH9ULfggo= =chx8 -----END PGP SIGNATURE----- _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
