Re: [PATCH] entry: Fix boot for !CONFIG_GENERIC_ENTRY

From: Kees Cook
Date: Tue Nov 24 2020 - 16:46:08 EST


On Mon, Nov 23, 2020 at 10:54:58AM -0500, Gabriel Krisman Bertazi wrote:
> Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> writes:
>
> > Jann Horn <jannh@xxxxxxxxxx> writes:
> >> As part of fixing this, it might be a good idea to put "enum
> >> syscall_work_bit" behind a "#ifdef CONFIG_GENERIC_ENTRY" to avoid
> >> future accidents like this?
> >
> > Hi Jan, Arnd,
> >
> > That is correct. This is a copy pasta mistake. My apologies. I didn't
> > have a !GENERIC_ENTRY device to test, but just the ifdef would have
> > caught it.
>
> I have patched it as suggested. Tested on qemu for arm32 and on bare
> metal for x86-64.
>
> Once again, my apologies for the mistake.
>
> -- >8 --
> Subject: [PATCH] entry: Fix boot for !CONFIG_GENERIC_ENTRY
>
> A copy-pasta mistake tries to set SYSCALL_WORK flags instead of TIF
> flags for !CONFIG_GENERIC_ENTRY. Also, add safeguards to catch this at
> compilation time.
>
> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> Suggested-by: Jann Horn <jannh@xxxxxxxxxx>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>

Thanks for getting this fixed!

3136b93c3fb2 ("entry: Expose helpers to migrate TIF to SYSCALL_WORK flags")
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook