From 5dce971acf2ae20c80d5e9d1f6bbf17376870911 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 9 Feb 2006 17:09:38 -0800 Subject: [PATCH] [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 Signed-off-by: David S. Miller --- net/bridge/br_netfilter.c | 53 ++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 15 deletions(-) diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c index 7cac3fb9f8..b5018166b0 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 @@ static struct rtable __fake_rtable = { .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 @@ static int br_nf_pre_routing_finish_bridge(struct sk_buff *skb) 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 @@ bridged_dnat: } /* 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 @@ static void setup_pre_routing(struct sk_buff *skb) 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 @@ static unsigned int br_nf_pre_routing_ipv6(unsigned int hook, 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 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb, 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 @@ static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb, 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 @@ static unsigned int br_nf_forward_ip(unsigned int hook, struct sk_buff **pskb, 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 @@ static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb, 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 @@ static unsigned int br_nf_local_out(unsigned int hook, struct sk_buff **pskb, /* 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 @@ static unsigned int br_nf_post_routing(unsigned int hook, struct sk_buff **pskb, 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 -- 2.39.5