On Thu, Dec 01, 2016 at 10:42:22AM +0100, Andrey Konovalov wrote:
> On Wed, Nov 30, 2016 at 8:42 PM, Marcelo Ricardo Leitner
> <marcelo.leitner@xxxxxxxxx> wrote:
> > Hi Andrey,
> >
> > Please let me know how this works for you. It seems good here, though
> > your poc may still trigger OOM through other means.
>
> Hi Marcelo,
>
> Don't see any reports with this patch.
>
> Thanks!
Thanks Andrey.
I'll post a v2 after a few more tests here and to s/OOM/OOM killer/ in
most of the changelog.
>
> >
> > Thanks,
> > Marcelo
> >
> > ---8<---
> >
> > Andrey Konovalov reported that this vmalloc call is based on an
> > userspace request and that it's spewing traces, which may flood the logs
> > and cause DoS if abused.
> >
> > Florian Westphal also mentioned that this call should not trigger OOM,
> > as kmalloc one is already not triggering it.
> >
> > This patch brings the vmalloc call in sync to kmalloc and disables the
> > warn trace on allocation failure and also disable OOM invocation.
> >
> > Note, however, that under such stress situation, other places may
> > trigger OOM invocation.
> >
> > Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> > Cc: Florian Westphal <fw@xxxxxxxxx>
> > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> > ---
> > net/netfilter/x_tables.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
> > index fc4977456c30e098197b4f987b758072c9cf60d9..dece525bf83a0098dad607fce665cd0bde228362 100644
> > --- a/net/netfilter/x_tables.c
> > +++ b/net/netfilter/x_tables.c
> > @@ -958,7 +958,9 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
> > if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
> > info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
> > if (!info) {
> > - info = vmalloc(sz);
> > + info = __vmalloc(sz, GFP_KERNEL | __GFP_NOWARN |
> > + __GFP_NORETRY | __GFP_HIGHMEM,
> > + PAGE_KERNEL);
> > if (!info)
> > return NULL;
> > }
> > --
> > 2.9.3
> >
>
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