Re: [PATCH] efi: READ_ONCE rng seed size before munmap
From: Ard Biesheuvel
Date: Mon Feb 17 2020 - 11:09:15 EST
On Mon, 17 Feb 2020 at 16:54, Greg KH <greg@xxxxxxxxx> wrote:
> On Mon, Feb 17, 2020 at 04:23:03PM +0100, Ard Biesheuvel wrote:
> > On Mon, 17 Feb 2020 at 13:34, Jason A. Donenfeld <Jason@xxxxxxxxx> wrote:
> > >
> > > This function is consistent with using size instead of seed->size
> > > (except for one place that this patch fixes), but it reads seed->size
> > > without using READ_ONCE, which means the compiler might still do
> > > something unwanted. So, this commit simply adds the READ_ONCE
> > > wrapper.
> > >
> > > Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> > > Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> > > Cc: stable@xxxxxxxxxxxxxxx
> > Thanks Jason
> > I've queued this in efi/urgent with a fixes: tag rather than a cc:
> > stable, since it only applies clean to v5.4 and later.
> Why do that? That just makes it harder for me to know to pick it up for
> 5.4 and newer.
> > We'll need a
> > backport to 4.14 and 4.19 as well, which has a trivial conflict
> > (s/add_bootloader_randomness/add_device_randomness/) but we'll need to
> > wait for this patch to hit Linus's tree first.
> Ok, if you are going to send it on to me for stable, that's fine, but
> usually you can just wait for the rejection notices for older kernels
> before having to worry about this. In other words, you are doing more
> work than you have to here :)
without any context is your preferred method?