[PATCH net] bridge: fix igmp / mld query parsing

Path	csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod
From	Linus Lüssing <linus.luessing@c0d3.blue>
Newsgroups	linux.kernel
Subject	[PATCH net] bridge: fix igmp / mld query parsing
Date	Tue, 03 May 2016 22:30:02 +0200
Message-ID	<ruP7c-6xa-15@gated-at.bofh.it> (permalink)
X-Original-To	netdev@vger.kernel.org
X-Greylist	delayed 516 seconds by postgrey-1.27 at vger.kernel.org; Tue, 03 May 2016 16:28:24 EDT
X-Mailer	git-send-email 2.8.0.rc3
MIME-Version	1.0
Content-Type	text/plain; charset=UTF-8
Content-Transfer-Encoding	8bit
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	82
Organization	linux.* mail to news gateway
X-Original-Cc	"David S . Miller" <davem@davemloft.net>, Stephen Hemminger <stephen@networkplumber.org>, bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Simon Wunderlich <sw@simonwunderlich.de>, Linus Lüssing <linus.luessing@c0d3.blue>
X-Original-Date	Tue, 3 May 2016 22:18:54 +0200
X-Original-Message-ID	<1462306734-4183-1-git-send-email-linus.luessing@c0d3.blue>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1393784

Show key headers only | View raw

With the newly introduced helper functions the skb pulling is hidden
in the checksumming function - and undone before returning to the
caller.

The IGMP and MLD query parsing functions in the bridge still
assumed that the skb is pointing to the beginning of the IGMP/MLD
message while it is now kept at the beginning of the IPv4/6 header.

If there is a querier somewhere else, then this either causes
the multicast snooping to stay disabled even though it could be
enabled. Or, if we have the querier enabled too, then this can
create unnecessary IGMP / MLD query messages on the link.

Fixing this by taking the offset between IP and IGMP/MLD header into
account, too.

Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code")
Reported-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 net/bridge/br_multicast.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 03661d9..7105cdf 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1271,6 +1271,7 @@ static int br_ip4_multicast_query(struct net_bridge *br,
 	unsigned long max_delay;
 	unsigned long now = jiffies;
 	__be32 group;
+	int offset = skb_transport_offset(skb);
 	int err = 0;
 
 	spin_lock(&br->multicast_lock);
@@ -1280,14 +1281,14 @@ static int br_ip4_multicast_query(struct net_bridge *br,
 
 	group = ih->group;
 
-	if (skb->len == sizeof(*ih)) {
+	if (skb->len == offset + sizeof(*ih)) {
 		max_delay = ih->code * (HZ / IGMP_TIMER_SCALE);
 
 		if (!max_delay) {
 			max_delay = 10 * HZ;
 			group = 0;
 		}
-	} else if (skb->len >= sizeof(*ih3)) {
+	} else if (skb->len >= offset + sizeof(*ih3)) {
 		ih3 = igmpv3_query_hdr(skb);
 		if (ih3->nsrcs)
 			goto out;
@@ -1350,6 +1351,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 	unsigned long now = jiffies;
 	const struct in6_addr *group = NULL;
 	bool is_general_query;
+	int offset = skb_transport_offset(skb);
 	int err = 0;
 
 	spin_lock(&br->multicast_lock);
@@ -1357,8 +1359,8 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 	    (port && port->state == BR_STATE_DISABLED))
 		goto out;
 
-	if (skb->len == sizeof(*mld)) {
-		if (!pskb_may_pull(skb, sizeof(*mld))) {
+	if (skb->len == offset + sizeof(*mld)) {
+		if (!pskb_may_pull(skb, offset + sizeof(*mld))) {
 			err = -EINVAL;
 			goto out;
 		}
@@ -1367,7 +1369,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 		if (max_delay)
 			group = &mld->mld_mca;
 	} else {
-		if (!pskb_may_pull(skb, sizeof(*mld2q))) {
+		if (!pskb_may_pull(skb, offset + sizeof(*mld2q))) {
 			err = -EINVAL;
 			goto out;
 		}
-- 
1.7.10.4

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH net] bridge: fix igmp / mld query parsing Linus Lüssing <linus.luessing@c0d3.blue> - 2016-05-03 22:30 +0200
  Re: [PATCH net] bridge: fix igmp / mld query parsing Stephen Hemminger <stephen@networkplumber.org> - 2016-05-03 22:30 +0200
    Re: [PATCH net] bridge: fix igmp / mld query parsing Linus Lüssing <linus.luessing@c0d3.blue> - 2016-05-04 17:00 +0200

csiph-web