lkml.org 
[lkml]   [2017]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: net/packet: use-after-free in packet_rcv_fanout
From
Date
On Fri, 2017-02-10 at 09:49 -0800, Cong Wang wrote:
> On Thu, Feb 9, 2017 at 7:23 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > On Thu, 2017-02-09 at 19:19 -0800, Eric Dumazet wrote:
> >
> >> More likely the bug is in fanout_add(), with a buggy sequence in error
> >> case, and not correct locking.
> >>
> >> kfree(po->rollover);
> >> po->rollover = NULL;
> >>
> >> Two cpus entering fanout_add() (using the same af_packet socket,
> >> syzkaller courtesy...) might both see po->fanout being NULL.
> >>
> >> Then they grab the mutex. Too late...
> >
> > Patch could be :
> >
>
> For me, clearly the data structure that use-after-free'd is struct sock
> rather than struct packet_rollover.

Fine. But your patch makes absolutely no sense.


\
 
 \ /
  Last update: 2017-02-10 19:07    [W:0.275 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site