[BRIDGE]: netfilter handle RCU during removal
Bridge netfilter code needs to handle the case where device is
removed from bridge while packet in process. In these cases the
bridge_parent can become null while processing.
This should fix: http://bugzilla.kernel.org/show_bug.cgi?id=5803
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 7cac3fb..b501816 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -51,9 +51,6 @@
#define store_orig_dstaddr(skb) (skb_origaddr(skb) = (skb)->nh.iph->daddr)
#define dnat_took_place(skb) (skb_origaddr(skb) != (skb)->nh.iph->daddr)
-#define has_bridge_parent(device) ((device)->br_port != NULL)
-#define bridge_parent(device) ((device)->br_port->br->dev)
-
#ifdef CONFIG_SYSCTL
static struct ctl_table_header *brnf_sysctl_header;
static int brnf_call_iptables = 1;
@@ -98,6 +95,12 @@
.rt_flags = 0,
};
+static inline struct net_device *bridge_parent(const struct net_device *dev)
+{
+ struct net_bridge_port *port = rcu_dereference(dev->br_port);
+
+ return port ? port->br->dev : NULL;
+}
/* PF_BRIDGE/PRE_ROUTING *********************************************/
/* Undo the changes made for ip6tables PREROUTING and continue the
@@ -189,11 +192,15 @@
skb->nf_bridge->mask ^= BRNF_NF_BRIDGE_PREROUTING;
skb->dev = bridge_parent(skb->dev);
- if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
- skb_pull(skb, VLAN_HLEN);
- skb->nh.raw += VLAN_HLEN;
+ if (!skb->dev)
+ kfree_skb(skb);
+ else {
+ if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+ skb_pull(skb, VLAN_HLEN);
+ skb->nh.raw += VLAN_HLEN;
+ }
+ skb->dst->output(skb);
}
- skb->dst->output(skb);
return 0;
}
@@ -270,7 +277,7 @@
}
/* Some common code for IPv4/IPv6 */
-static void setup_pre_routing(struct sk_buff *skb)
+static struct net_device *setup_pre_routing(struct sk_buff *skb)
{
struct nf_bridge_info *nf_bridge = skb->nf_bridge;
@@ -282,6 +289,8 @@
nf_bridge->mask |= BRNF_NF_BRIDGE_PREROUTING;
nf_bridge->physindev = skb->dev;
skb->dev = bridge_parent(skb->dev);
+
+ return skb->dev;
}
/* We only check the length. A bridge shouldn't do any hop-by-hop stuff anyway */
@@ -376,7 +385,8 @@
nf_bridge_put(skb->nf_bridge);
if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
return NF_DROP;
- setup_pre_routing(skb);
+ if (!setup_pre_routing(skb))
+ return NF_DROP;
NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
br_nf_pre_routing_finish_ipv6);
@@ -465,7 +475,8 @@
nf_bridge_put(skb->nf_bridge);
if ((nf_bridge = nf_bridge_alloc(skb)) == NULL)
return NF_DROP;
- setup_pre_routing(skb);
+ if (!setup_pre_routing(skb))
+ return NF_DROP;
store_orig_dstaddr(skb);
NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
@@ -539,11 +550,16 @@
struct sk_buff *skb = *pskb;
struct nf_bridge_info *nf_bridge;
struct vlan_ethhdr *hdr = vlan_eth_hdr(skb);
+ struct net_device *parent;
int pf;
if (!skb->nf_bridge)
return NF_ACCEPT;
+ parent = bridge_parent(out);
+ if (!parent)
+ return NF_DROP;
+
if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
pf = PF_INET;
else
@@ -564,8 +580,8 @@
nf_bridge->mask |= BRNF_BRIDGED;
nf_bridge->physoutdev = skb->dev;
- NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in),
- bridge_parent(out), br_nf_forward_finish);
+ NF_HOOK(pf, NF_IP_FORWARD, skb, bridge_parent(in), parent,
+ br_nf_forward_finish);
return NF_STOLEN;
}
@@ -688,6 +704,8 @@
goto out;
}
realoutdev = bridge_parent(skb->dev);
+ if (!realoutdev)
+ return NF_DROP;
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
/* iptables should match -o br0.x */
@@ -701,9 +719,11 @@
/* IP forwarded traffic has a physindev, locally
* generated traffic hasn't. */
if (realindev != NULL) {
- if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT) &&
- has_bridge_parent(realindev))
- realindev = bridge_parent(realindev);
+ if (!(nf_bridge->mask & BRNF_DONT_TAKE_PARENT) ) {
+ struct net_device *parent = bridge_parent(realindev);
+ if (parent)
+ realindev = parent;
+ }
NF_HOOK_THRESH(pf, NF_IP_FORWARD, skb, realindev,
realoutdev, br_nf_local_out_finish,
@@ -743,6 +763,9 @@
if (!nf_bridge)
return NF_ACCEPT;
+ if (!realoutdev)
+ return NF_DROP;
+
if (skb->protocol == __constant_htons(ETH_P_IP) || IS_VLAN_IP)
pf = PF_INET;
else