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netfilter: nf_tables_bridge: use nft_set_pktinfo_ipv{4, 6}_validate

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Consolidate pktinfo setup and validation by using the new generic
functions so we converge to the netdev family codebase.

We only need a linear IPv4 and IPv6 header from the reject expression,
so move nft_bridge_iphdr_validate() and nft_bridge_ip6hdr_validate()
to net/bridge/netfilter/nft_reject_bridge.c.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2016-09-09 12:42:52 +02:00
parent ddc8b6027a
commit 10151d7b03
3 changed files with 45 additions and 78 deletions
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7
include/net/netfilter/nf_tables_bridge.h
View File

@ -1,7 +0,0 @@
#ifndef _NET_NF_TABLES_BRIDGE_H
#define _NET_NF_TABLES_BRIDGE_H
int nft_bridge_iphdr_validate(struct sk_buff *skb);
int nft_bridge_ip6hdr_validate(struct sk_buff *skb);
#endif /* _NET_NF_TABLES_BRIDGE_H */

72
net/bridge/netfilter/nf_tables_bridge.c
View File

@ -13,79 +13,11 @@
#include <linux/module.h>
#include <linux/netfilter_bridge.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_bridge.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/netfilter/nf_tables_ipv4.h>
#include <net/netfilter/nf_tables_ipv6.h>
int nft_bridge_iphdr_validate(struct sk_buff *skb)
{
struct iphdr *iph;
u32 len;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
return 0;
iph = ip_hdr(skb);
if (iph->ihl < 5 || iph->version != 4)
return 0;
len = ntohs(iph->tot_len);
if (skb->len < len)
return 0;
else if (len < (iph->ihl*4))
return 0;
if (!pskb_may_pull(skb, iph->ihl*4))
return 0;
return 1;
}
EXPORT_SYMBOL_GPL(nft_bridge_iphdr_validate);
int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
{
struct ipv6hdr *hdr;
u32 pkt_len;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
return 0;
hdr = ipv6_hdr(skb);
if (hdr->version != 6)
return 0;
pkt_len = ntohs(hdr->payload_len);
if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
return 0;
return 1;
}
EXPORT_SYMBOL_GPL(nft_bridge_ip6hdr_validate);
static inline void nft_bridge_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
if (nft_bridge_iphdr_validate(skb))
nft_set_pktinfo_ipv4(pkt, skb, state);
else
nft_set_pktinfo_unspec(pkt, skb, state);
}
static inline void nft_bridge_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
#if IS_ENABLED(CONFIG_IPV6)
if (nft_bridge_ip6hdr_validate(skb) &&
nft_set_pktinfo_ipv6(pkt, skb, state) == 0)
return;
#endif
nft_set_pktinfo_unspec(pkt, skb, state);
}
static unsigned int
nft_do_chain_bridge(void *priv,
struct sk_buff *skb,
@ -95,10 +27,10 @@ nft_do_chain_bridge(void *priv,
switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
nft_bridge_set_pktinfo_ipv4(&pkt, skb, state);
nft_set_pktinfo_ipv4_validate(&pkt, skb, state);
break;
case htons(ETH_P_IPV6):
nft_bridge_set_pktinfo_ipv6(&pkt, skb, state);
nft_set_pktinfo_ipv6_validate(&pkt, skb, state);
break;
default:
nft_set_pktinfo_unspec(&pkt, skb, state);

44
net/bridge/netfilter/nft_reject_bridge.c
View File

@ -14,7 +14,6 @@
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nft_reject.h>
#include <net/netfilter/nf_tables_bridge.h>
#include <net/netfilter/ipv4/nf_reject.h>
#include <net/netfilter/ipv6/nf_reject.h>
#include <linux/ip.h>
@ -37,6 +36,30 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
skb_pull(nskb, ETH_HLEN);
}
static int nft_bridge_iphdr_validate(struct sk_buff *skb)
{
struct iphdr *iph;
u32 len;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
return 0;
iph = ip_hdr(skb);
if (iph->ihl < 5 || iph->version != 4)
return 0;
len = ntohs(iph->tot_len);
if (skb->len < len)
return 0;
else if (len < (iph->ihl*4))
return 0;
if (!pskb_may_pull(skb, iph->ihl*4))
return 0;
return 1;
}
/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
* or the bridge port (NF_BRIDGE PREROUTING).
*/
@ -143,6 +166,25 @@ static void nft_reject_br_send_v4_unreach(struct net *net,
br_forward(br_port_get_rcu(dev), nskb, false, true);
}
static int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
{
struct ipv6hdr *hdr;
u32 pkt_len;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
return 0;
hdr = ipv6_hdr(skb);
if (hdr->version != 6)
return 0;
pkt_len = ntohs(hdr->payload_len);
if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
return 0;
return 1;
}
static void nft_reject_br_send_v6_tcp_reset(struct net *net,
struct sk_buff *oldskb,
const struct net_device *dev,