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[4.2.y-ckt,stable] Patch "bridge: fix igmp / mld query parsing" has been added to the 4.2.y-ckt tree

Message ID 1464112395-349-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa May 24, 2016, 5:53 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    bridge: fix igmp / mld query parsing

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

From f6daa117f633b3defaa1b6d98d2e04e45df32e5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20L=C3=BCssing?= <linus.luessing@c0d3.blue>
Date: Wed, 4 May 2016 17:25:02 +0200
Subject: bridge: fix igmp / mld query parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 856ce5d083e14571d051301fe3c65b32b8cbe321 upstream.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 net/bridge/br_multicast.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--
2.7.4
diff mbox

Patch

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 03cdb9e..e58d0f6 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1254,6 +1254,7 @@  static int br_ip4_multicast_query(struct net_bridge *br,
 	struct br_ip saddr;
 	unsigned long max_delay;
 	unsigned long now = jiffies;
+	unsigned int offset = skb_transport_offset(skb);
 	__be32 group;
 	int err = 0;

@@ -1264,14 +1265,14 @@  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;
@@ -1332,6 +1333,7 @@  static int br_ip6_multicast_query(struct net_bridge *br,
 	struct br_ip saddr;
 	unsigned long max_delay;
 	unsigned long now = jiffies;
+	unsigned int offset = skb_transport_offset(skb);
 	const struct in6_addr *group = NULL;
 	bool is_general_query;
 	int err = 0;
@@ -1341,8 +1343,8 @@  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;
 		}
@@ -1351,7 +1353,7 @@  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;
 		}