Re: [RFC PATCH 12/17] gcc-plugins: objtool: Add plugin to detect switch table on arm64
From: Mark Brown <broonie@kernel.org>
Date: 2021-02-03 13:06:42
Also in:
linux-efi, linux-hardening, lkml
On Tue, Feb 02, 2021 at 06:14:14PM -0600, Josh Poimboeuf wrote:
On Tue, Feb 02, 2021 at 03:01:22PM -0800, Nick Desaulniers wrote:
quoted
I wonder if PAC or BTI also make this slightly more complex? PAC at least has implications for unwinders, IIUC.
What is PAC/BTI?
PAC and BTI are ARM architecture extensions. PAC uses a tag in pointers to sign and verify them, presenting a barrier to ROP, and when BTI is active only specific instructions can be branched to. Since PAC modifies pointers when it is active the unwinder has to undo the tagging to understand what's being pointed to, that's already there.