From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH net] ipv4: initialize flowi4_flags before calling fib_lookup() Date: Tue, 22 Mar 2016 13:00:48 -0600 Message-ID: <56F19660.4040502@cumulusnetworks.com> References: <1458673017-3528-1-git-send-email-lrichard@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: Lance Richardson , netdev@vger.kernel.org Return-path: Received: from mail-ig0-f179.google.com ([209.85.213.179]:35473 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751604AbcCVTAw (ORCPT ); Tue, 22 Mar 2016 15:00:52 -0400 Received: by mail-ig0-f179.google.com with SMTP id cl4so61007577igb.0 for ; Tue, 22 Mar 2016 12:00:52 -0700 (PDT) In-Reply-To: <1458673017-3528-1-git-send-email-lrichard@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 3/22/16 12:56 PM, 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 the entire fl4 structure, which will prevent > similar issues as fields are added in the future by ensuring that > all fields are initialized to zero unless explicitly initialized > to another value. > > Fixes: 58189ca7b2741 ("net: Fix vti use case with oif in dst lookups") > Suggested-by: David Ahern > Signed-off-by: Lance Richardson > --- > net/ipv4/fib_frontend.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) > > diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c > index 21add55..8a9246d 100644 > --- a/net/ipv4/fib_frontend.c > +++ b/net/ipv4/fib_frontend.c > @@ -280,7 +280,6 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) > struct in_device *in_dev; > struct fib_result res; > struct rtable *rt; > - struct flowi4 fl4; > struct net *net; > int scope; > > @@ -296,14 +295,13 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) > > scope = RT_SCOPE_UNIVERSE; > if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) { > - fl4.flowi4_oif = 0; > - fl4.flowi4_iif = LOOPBACK_IFINDEX; > - fl4.daddr = ip_hdr(skb)->saddr; > - fl4.saddr = 0; > - fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); > - fl4.flowi4_scope = scope; > - fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0; > - fl4.flowi4_tun_key.tun_id = 0; > + 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, > + }; > if (!fib_lookup(net, &fl4, &res, 0)) > return FIB_RES_PREFSRC(net, res); > } else { > Acked-by: David Ahern DaveM: this should go into stable releases back to v4.3.