Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933542AbcKNQTo (ORCPT ); Mon, 14 Nov 2016 11:19:44 -0500 Received: from mail-pg0-f43.google.com ([74.125.83.43]:35386 "EHLO mail-pg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbcKNQTk (ORCPT ); Mon, 14 Nov 2016 11:19:40 -0500 Subject: Re: [PATCH v3] ip6_output: ensure flow saddr actually belongs to device To: "Jason A. Donenfeld" , Netdev , WireGuard mailing list , LKML , YOSHIFUJI Hideaki , Hannes Frederic Sowa References: <27cccef1-06d9-74b3-5b8a-912850119a76@cumulusnetworks.com> <20161113232813.28926-1-Jason@zx2c4.com> From: David Ahern Message-ID: <87012eb2-e52d-7058-4115-a4a3c70a7b4c@cumulusnetworks.com> Date: Mon, 14 Nov 2016 09:19:37 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161113232813.28926-1-Jason@zx2c4.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1482 Lines: 39 On 11/13/16 4:28 PM, Jason A. Donenfeld wrote: > This puts the IPv6 routing functions in parity with the IPv4 routing > functions. Namely, we now check in v6 that if a flowi6 requests an > saddr, the returned dst actually corresponds to a net device that has > that saddr. This mirrors the v4 logic with __ip_dev_find in > __ip_route_output_key_hash. In the event that the returned dst is not > for a dst with a dev that has the saddr, we return -EINVAL, just like > v4; this makes it easy to use the same error handlers for both cases. > > Signed-off-by: Jason A. Donenfeld > Cc: David Ahern > --- > Changes from v2: > It turns out ipv6_chk_addr already has the device enumeration > logic that we need by simply passing NULL. > > net/ipv6/ip6_output.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c > index 6001e78..b3b5cb6 100644 > --- a/net/ipv6/ip6_output.c > +++ b/net/ipv6/ip6_output.c > @@ -926,6 +926,10 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, > int err; > int flags = 0; > > + if (!ipv6_addr_any(&fl6->saddr) && > + !ipv6_chk_addr(net, &fl6->saddr, NULL, 1)) > + return -EINVAL; > + > /* The correct way to handle this would be to do > * ip6_route_get_saddr, and then ip6_route_output; however, > * the route-specific preferred source forces the > LGTM Acked-by: David Ahern