Commit 13c164b1a186 - regression for LSMs/SELinux?

[Linus Torvalds]

On Tue, Sep 29, 2020 at 5:16 AM Ondrej Mosnacek <omosnace at redhat.com> wrote:
>
> OK, so it seems that reverting comes out as the best choice here.

Yeah.

> BTW, I'm looking at rw_verify_area() and I see this "If (ppos)" check
> and the comment above it... And then I look at autofs_write(), which
> passes &file->f_pos, while ksys_write() passes file_ppos(file)

Ok, that doesn't matter for the security_file_permission() issue, but
yes, autofs is doing the traditional thing, and it's pointless. Using
file_ppos(file) isn't an option since it's an inline to read_write.c,
but it could just pass in NULL these days and avoid that too.

So how about we just do the appended patch? Can whoever sees this
problem just verify, even though it looks trivially correct...

            Linus