netdev - [PATCH 2/5] bridge: Fix IPv6 multicast snooping by correcting offset in MLDv2 report

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Message-Id: <1297811961-19249-3-git-send-email-linus.luessing@web.de>
Date:	Wed, 16 Feb 2011 00:19:18 +0100
From:	Linus Lüssing <linus.luessing@....de>
To:	Stephen Hemminger <shemminger@...ux-foundation.org>,
	"David S. Miller" <davem@...emloft.net>,
	bridge@...ts.linux-foundation.org
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Linus Lüssing <linus.luessing@....de>
Subject: [PATCH 2/5] bridge: Fix IPv6 multicast snooping by correcting offset in MLDv2 report

We actually want a pointer to the grec_nsrcr and not the following
field. Otherwise we can get very high values for *nsrcs as the first two
bytes of the IPv6 multicast address are being used instead, leading to
a failing pskb_may_pull() which results in MLDv2 reports not being
parsed.

Signed-off-by: Linus Lüssing <linus.luessing@....de>
---
 net/bridge/br_multicast.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 135d929..45dcf10 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1014,7 +1014,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br,
 
 		nsrcs = skb_header_pointer(skb,
 					   len + offsetof(struct mld2_grec,
-							  grec_mca),
+							  grec_nsrcs),
 					   sizeof(_nsrcs), &_nsrcs);
 		if (!nsrcs)
 			return -EINVAL;
-- 
1.7.2.3

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