From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lance Richardson Subject: Re: [PATCH net] ipv4: initialize flowi4_flags before calling fib_lookup() Date: Tue, 22 Mar 2016 14:41:48 -0400 (EDT) Message-ID: <950377980.72657238.1458672108040.JavaMail.zimbra@redhat.com> References: <1458660679-7279-1-git-send-email-lrichard@redhat.com> <56F18EEE.4070000@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Ahern Return-path: Received: from mx3-phx2.redhat.com ([209.132.183.24]:53449 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbcCVSlu (ORCPT ); Tue, 22 Mar 2016 14:41:50 -0400 In-Reply-To: <56F18EEE.4070000@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: ----- Original Message ----- > From: "David Ahern" > To: "Lance Richardson" , netdev@vger.kernel.org > Sent: Tuesday, March 22, 2016 2:29:02 PM > Subject: Re: [PATCH net] ipv4: initialize flowi4_flags before calling fib_lookup() > > On 3/22/16 9:31 AM, Lance Richardson wrote: > > Field fl4.flowi4_flags is not initialized in fib_compute_spec_dst() > > before calling fib_lookup(), which means fib_table_lookup() is > > using non-deterministic data at this line: > > > > if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) { > > > > Fix by initializing fl4.flowi4_flags to zero. > > > > Signed-off-by: Lance Richardson > > --- > > net/ipv4/fib_frontend.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c > > index 21add55..896844a 100644 > > --- a/net/ipv4/fib_frontend.c > > +++ b/net/ipv4/fib_frontend.c > > @@ -304,6 +304,7 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) > > fl4.flowi4_scope = scope; > > fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0; > > fl4.flowi4_tun_key.tun_id = 0; > > + fl4.flowi4_flags = 0; > > if (!fib_lookup(net, &fl4, &res, 0)) > > return FIB_RES_PREFSRC(net, res); > > } else { > > > > Fixes: 58189ca7b2741 ("net: Fix vti use case with oif in dst lookups") > > I think a more robust solution is to move fl4 to this if case and init > when it is declared: > > struct flowi4 fl4 = { > .flowi4_iif = LOOPBACK_IFINDEX, > .daddr = ip_hdr(skb)->saddr, > .flowi4_tos = RT_TOS(ip_hdr(skb)->tos), > .flowi4_scope = scope, > .flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0, > }; > Agreed... I actually debated doing something similar but opted for the smaller delta. v2 coming up. Thanks for the review, Lance