Re: [PATCH v9 00/11] x86: PIE support to extend KASLR randomization

Borislav Petkov
2019-08-06T15:43:52Z

On Tue, Jul 30, 2019 at 12:12:44PM -0700, Thomas Garnier wrote:
> These patches make some of the changes necessary to build the kernel as
> Position Independent Executable (PIE) on x86_64. Another patchset will
> add the PIE option and larger architecture changes.

Yeah, about this: do we have a longer writeup about the actual benefits
of all this and why we should take this all? After all, after looking
at the first couple of asm patches, it is posing restrictions to how
we deal with virtual addresses in asm (only RIP-relative addressing in
64-bit mode, MOVs with 64-bit immediates, etc, for example) and I'm
willing to bet money that some future unrelated change will break PIE
sooner or later. And I'd like to have a better justification why we
should enforce those new "rules" unconditionally.

Thx.

--
Regards/Gruss,
Boris.

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