From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: "Magnus Karlsson" <magnus.karlsson@intel.com>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Network Development" <netdev@vger.kernel.org>,
kal.conley@dectris.com, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf] xsk: fix registration of Rx-only sockets
Date: Wed, 23 Oct 2019 20:22:58 -0700 [thread overview]
Message-ID: <CAADnVQ+t6ThJM_hfm9JvCApXdYfJLFNGdDd0ykBf-czvHeDAGQ@mail.gmail.com> (raw)
In-Reply-To: <B551C016-76AE-46D3-B2F5-15AFF9073735@gmail.com>
On Wed, Oct 23, 2019 at 4:03 PM Jonathan Lemon <jonathan.lemon@gmail.com> wrote:
>
> On 21 Oct 2019, at 1:16, Magnus Karlsson wrote:
>
> > Having Rx-only AF_XDP sockets can potentially lead to a crash in the
> > system by a NULL pointer dereference in xsk_umem_consume_tx(). This
> > function iterates through a list of all sockets tied to a umem and
> > checks if there are any packets to send on the Tx ring. Rx-only
> > sockets do not have a Tx ring, so this will cause a NULL pointer
> > dereference. This will happen if you have registered one or more
> > Rx-only sockets to a umem and the driver is checking the Tx ring even
> > on Rx, or if the XDP_SHARED_UMEM mode is used and there is a mix of
> > Rx-only and other sockets tied to the same umem.
> >
> > Fixed by only putting sockets with a Tx component on the list that
> > xsk_umem_consume_tx() iterates over.
>
> A future improvement might be renaming umem->xsk_list to umem->xsk_tx_list
> or similar, in order to make it clear that the list is only used on the
> TX path.
>
> >
> > Fixes: ac98d8aab61b ("xsk: wire upp Tx zero-copy functions")
> > Reported-by: Kal Cutter Conley <kal.conley@dectris.com>
> > Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
>
> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Applied. Thanks
next prev parent reply other threads:[~2019-10-24 3:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 8:16 [PATCH bpf] xsk: fix registration of Rx-only sockets Magnus Karlsson
2019-10-23 23:03 ` Jonathan Lemon
2019-10-24 3:22 ` Alexei Starovoitov [this message]
2019-10-24 12:53 ` Magnus Karlsson
2019-10-24 15:19 ` Alexei Starovoitov
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