Re: [PATCH net-next 2/2] xfrm: Fix unaligned access in xfrm_notify_sa() for DELSA
From: Sowmini Varadhan
Date: Wed Oct 21 2015 - 06:55:14 EST
On (10/21/15 08:57), Steffen Klassert wrote:
> > --- a/net/xfrm/xfrm_user.c
> > +++ b/net/xfrm/xfrm_user.c
> > @@ -2659,7 +2659,7 @@ static int xfrm_notify_sa(struct xfrm_state *x, const struct km_event *c)
> > if (attr == NULL)
> > goto out_free_skb;
> >
> > - p = nla_data(attr);
> > + p = PTR_ALIGN(nla_data(attr), __alignof__(*p));
>
> Hm, this breaks userspace notifications on 64-bit systems.
> Userspace expects this to be aligned to 4, with your patch
> it is aligned to 8 on 64-bit.
>
> Without your patch I get the correct notification when deleting a SA:
>
But __alignof__(*p) is 8 on sparc, and without the patch I get
all types of unaligned access. So what do you suggest as the fix?
(and openswan/pluto dont flag any errors with the patch, which is
a separate bug).
--Sowmini
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