提交 7f285fa7 编写于 作者: H Herbert Xu 提交者: David S. Miller

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: NFrank Arnold <frank.arnold@amd.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Thanks,
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 bcfcc450
......@@ -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)
......
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