From 7f285fa78d4b81b8458f05e77fb6b46245121b4e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 5 Jul 2010 14:50:08 +0000 Subject: [PATCH] bridge br_multicast: BUG: unable to handle kernel NULL pointer dereference On Tue, Jul 06, 2010 at 08:48:35AM +0800, Herbert Xu wrote: > > bridge: Restore NULL check in br_mdb_ip_get Resend with proper attribution. bridge: Restore NULL check in br_mdb_ip_get Somewhere along the line the NULL check in br_mdb_ip_get went AWOL, causing crashes when we receive an IGMP packet with no multicast table allocated. This patch restores it and ensures all br_mdb_*_get functions use it. Reported-by: Frank Arnold Signed-off-by: Herbert Xu Thanks, Signed-off-by: David S. Miller --- net/bridge/br_multicast.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 9d21d98ae5fa..27ae946363f1 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -99,6 +99,15 @@ static struct net_bridge_mdb_entry *__br_mdb_ip_get( return NULL; } +static struct net_bridge_mdb_entry *br_mdb_ip_get( + struct net_bridge_mdb_htable *mdb, struct br_ip *dst) +{ + if (!mdb) + return NULL; + + return __br_mdb_ip_get(mdb, dst, br_ip_hash(mdb, dst)); +} + static struct net_bridge_mdb_entry *br_mdb_ip4_get( struct net_bridge_mdb_htable *mdb, __be32 dst) { @@ -107,7 +116,7 @@ static struct net_bridge_mdb_entry *br_mdb_ip4_get( br_dst.u.ip4 = dst; br_dst.proto = htons(ETH_P_IP); - return __br_mdb_ip_get(mdb, &br_dst, __br_ip4_hash(mdb, dst)); + return br_mdb_ip_get(mdb, &br_dst); } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) @@ -119,23 +128,17 @@ static struct net_bridge_mdb_entry *br_mdb_ip6_get( ipv6_addr_copy(&br_dst.u.ip6, dst); br_dst.proto = htons(ETH_P_IPV6); - return __br_mdb_ip_get(mdb, &br_dst, __br_ip6_hash(mdb, dst)); + return br_mdb_ip_get(mdb, &br_dst); } #endif -static struct net_bridge_mdb_entry *br_mdb_ip_get( - struct net_bridge_mdb_htable *mdb, struct br_ip *dst) -{ - return __br_mdb_ip_get(mdb, dst, br_ip_hash(mdb, dst)); -} - struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br, struct sk_buff *skb) { struct net_bridge_mdb_htable *mdb = br->mdb; struct br_ip ip; - if (!mdb || br->multicast_disabled) + if (br->multicast_disabled) return NULL; if (BR_INPUT_SKB_CB(skb)->igmp) -- 2.20.1