Re: [PATCH 0/7] CFI for ARM32 using LLVM

Linus Walleij
2024-02-27T13:48:25Z

On Tue, Feb 27, 2024 at 2:06 AM Kees Cook <keescook@chromium.org> wrote:

> On Sun, Feb 25, 2024 at 09:08:09PM +0100, Linus Walleij wrote:
> > This is a first patch set to support CLANG CFI (Control Flow
> > Integrity) on ARM32.
>
> Yay!
>
> Is CONFIG_CFI_PERMISSIVE=y expected to work with this series?

I enable that and what happens when I trigger a crash is that the
process shell is killed and I return to login prompt (busybox).
I guess that is expected behaviour for permissive?

> I wasn't able to build with CONFIG_FTRACE=y; I got this link error:
> ld.lld: error: undefined symbol: ftrace_stub_graph
> (FWIW, I'm building against v6.8-rc2, maybe I need a different base?)

I get that too, from the buildbots, but I'm clueless about what it is.
All of it is in generic code, nothing ARM32-specific, maybe some bug
in v6.8-rc1 that was fixed (I wish...) Sami?

> But yes, I can boot and prototype mismatches are caught. Whee! :)

Sweet!

Yours,
Linus Walleij