This patch exports the functions nft_reject_iphdr_validate and
nft_reject_ip6hdr_validate to use it in follow up patches.
These functions check if the ethernet header is correct.
Signed-off-by: Alvaro Neira Ayuso <alvaroneay@xxxxxxxxx>
---
include/net/netfilter/nf_tables_bridge.h | 7 ++++
net/bridge/netfilter/nf_tables_bridge.c | 48 +++++++++++++++++++++++++++
net/bridge/netfilter/nft_reject_bridge.c | 52 +++---------------------------
3 files changed, 60 insertions(+), 47 deletions(-)
create mode 100644 include/net/netfilter/nf_tables_bridge.h
diff --git a/include/net/netfilter/nf_tables_bridge.h b/include/net/netfilter/nf_tables_bridge.h
new file mode 100644
index 0000000..511fb79
--- /dev/null
+++ b/include/net/netfilter/nf_tables_bridge.h
@@ -0,0 +1,7 @@
+#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 */
diff --git a/net/bridge/netfilter/nf_tables_bridge.c b/net/bridge/netfilter/nf_tables_bridge.c
index 074c557..d468c19 100644
--- a/net/bridge/netfilter/nf_tables_bridge.c
+++ b/net/bridge/netfilter/nf_tables_bridge.c
@@ -13,6 +13,54 @@
#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>
+
+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 unsigned int
nft_do_chain_bridge(const struct nf_hook_ops *ops,
diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c
index 654c901..1285f25 100644
--- a/net/bridge/netfilter/nft_reject_bridge.c
+++ b/net/bridge/netfilter/nft_reject_bridge.c
@@ -14,6 +14,7 @@
#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>
@@ -34,30 +35,6 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
skb_pull(nskb, ETH_HLEN);
}
-static int nft_reject_iphdr_validate(struct sk_buff *oldskb)
-{
- struct iphdr *iph;
- u32 len;
-
- if (!pskb_may_pull(oldskb, sizeof(struct iphdr)))
- return 0;
-
- iph = ip_hdr(oldskb);
- if (iph->ihl < 5 || iph->version != 4)
- return 0;
-
- len = ntohs(iph->tot_len);
- if (oldskb->len < len)
- return 0;
- else if (len < (iph->ihl*4))
- return 0;
-
- if (!pskb_may_pull(oldskb, iph->ihl*4))
- return 0;
-
- return 1;
-}
-
static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)
{
struct sk_buff *nskb;
@@ -65,7 +42,7 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)
const struct tcphdr *oth;
struct tcphdr _oth;
- if (!nft_reject_iphdr_validate(oldskb))
+ if (!nft_bridge_iphdr_validate(oldskb))
return;
oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
@@ -100,7 +77,7 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
void *payload;
__wsum csum;
- if (!nft_reject_iphdr_validate(oldskb))
+ if (!nft_bridge_iphdr_validate(oldskb))
return;
/* IP header checks: fragment. */
@@ -145,25 +122,6 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
br_deliver(br_port_get_rcu(oldskb->dev), nskb);
}
-static int nft_reject_ip6hdr_validate(struct sk_buff *oldskb)
-{
- struct ipv6hdr *hdr;
- u32 pkt_len;
-
- if (!pskb_may_pull(oldskb, sizeof(struct ipv6hdr)))
- return 0;
-
- hdr = ipv6_hdr(oldskb);
- if (hdr->version != 6)
- return 0;
-
- pkt_len = ntohs(hdr->payload_len);
- if (pkt_len + sizeof(struct ipv6hdr) > oldskb->len)
- return 0;
-
- return 1;
-}
-
static void nft_reject_br_send_v6_tcp_reset(struct net *net,
struct sk_buff *oldskb, int hook)
{
@@ -173,7 +131,7 @@ static void nft_reject_br_send_v6_tcp_reset(struct net *net,
unsigned int otcplen;
struct ipv6hdr *nip6h;
- if (!nft_reject_ip6hdr_validate(oldskb))
+ if (!nft_bridge_ip6hdr_validate(oldskb))
return;
oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
@@ -206,7 +164,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net,
unsigned int len;
void *payload;
- if (!nft_reject_ip6hdr_validate(oldskb))
+ if (!nft_bridge_ip6hdr_validate(oldskb))
return;
/* Include "As much of invoking packet as possible without the ICMPv6
--
1.7.10.4
--
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