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 <frank.arnold@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Thanks,
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 9d21d98..27ae946 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -99,6 +99,15 @@
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 @@
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 @@
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)
