lkml.org 
[lkml]   [2015]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH net-next 2/2] xfrm: Fix unaligned access in xfrm_notify_sa() for DELSA
    From
    From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
    Date: Wed, 21 Oct 2015 06:54:42 -0400

    > 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?

    The accesses have to be done using something like get_unaligned() and
    put_unaligned().

    Sorry, but the protocol is set in stone and this is unfortunately how
    it is.


    \
     
     \ /
      Last update: 2015-10-21 15:21    [W:4.518 / U:0.708 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site