Re: [PATCH v3 3/5] mm: Make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long

From: Florent Revest
Date: Tue Jul 04 2023 - 11:46:09 EST


On Tue, Jul 4, 2023 at 5:37 PM Florent Revest <revest@xxxxxxxxxxxx> wrote:
>
> Defining a prctl flag as an int is a footgun because on a 64 bit machine
> and with a variadic implementation of prctl (like in musl and glibc),
> when used directly as a prctl argument, it can get casted to long with
> garbage upper bits which would result in unexpected behaviors.
>
> This patch changes the constant to an unsigned long to eliminate that
> possibilities. This does not break UAPI.
>
> Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
> Cc: linux-stable@xxxxxxxxxxxxxxx

Oops, this was supposed to be stable@xxxxxxxxxxxxxxx... I'll fix that
tag as part of v4.