netfilter: nf_tables_bridge: export nft_reject_ip*hdr_validate functions
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 IPv4/IPv6 header is correct. Signed-off-by: Alvaro Neira Ayuso <alvaroneay@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ -0,0 +1,7 @@
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#ifndef _NET_NF_TABLES_BRIDGE_H
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#define _NET_NF_TABLES_BRIDGE_H
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int nft_bridge_iphdr_validate(struct sk_buff *skb);
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int nft_bridge_ip6hdr_validate(struct sk_buff *skb);
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#endif /* _NET_NF_TABLES_BRIDGE_H */
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@ -13,6 +13,54 @@
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#include <linux/module.h>
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#include <linux/netfilter_bridge.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_bridge.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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int nft_bridge_iphdr_validate(struct sk_buff *skb)
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{
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struct iphdr *iph;
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u32 len;
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if (!pskb_may_pull(skb, sizeof(struct iphdr)))
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return 0;
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iph = ip_hdr(skb);
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if (iph->ihl < 5 || iph->version != 4)
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return 0;
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len = ntohs(iph->tot_len);
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if (skb->len < len)
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return 0;
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else if (len < (iph->ihl*4))
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return 0;
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if (!pskb_may_pull(skb, iph->ihl*4))
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return 0;
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return 1;
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}
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EXPORT_SYMBOL_GPL(nft_bridge_iphdr_validate);
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int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
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{
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struct ipv6hdr *hdr;
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u32 pkt_len;
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if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
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return 0;
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hdr = ipv6_hdr(skb);
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if (hdr->version != 6)
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return 0;
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pkt_len = ntohs(hdr->payload_len);
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if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
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return 0;
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return 1;
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}
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EXPORT_SYMBOL_GPL(nft_bridge_ip6hdr_validate);
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static unsigned int
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nft_do_chain_bridge(const struct nf_hook_ops *ops,
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@ -14,6 +14,7 @@
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nft_reject.h>
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#include <net/netfilter/nf_tables_bridge.h>
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#include <net/netfilter/ipv4/nf_reject.h>
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#include <net/netfilter/ipv6/nf_reject.h>
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#include <linux/ip.h>
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@ -35,30 +36,6 @@ static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
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skb_pull(nskb, ETH_HLEN);
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}
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static int nft_reject_iphdr_validate(struct sk_buff *oldskb)
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{
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struct iphdr *iph;
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u32 len;
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if (!pskb_may_pull(oldskb, sizeof(struct iphdr)))
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return 0;
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iph = ip_hdr(oldskb);
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if (iph->ihl < 5 || iph->version != 4)
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return 0;
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len = ntohs(iph->tot_len);
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if (oldskb->len < len)
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return 0;
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else if (len < (iph->ihl*4))
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return 0;
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if (!pskb_may_pull(oldskb, iph->ihl*4))
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return 0;
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return 1;
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}
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static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)
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{
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struct sk_buff *nskb;
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@ -66,7 +43,7 @@ static void nft_reject_br_send_v4_tcp_reset(struct sk_buff *oldskb, int hook)
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const struct tcphdr *oth;
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struct tcphdr _oth;
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if (!nft_reject_iphdr_validate(oldskb))
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if (!nft_bridge_iphdr_validate(oldskb))
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return;
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oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
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@ -101,7 +78,7 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
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void *payload;
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__wsum csum;
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if (!nft_reject_iphdr_validate(oldskb))
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if (!nft_bridge_iphdr_validate(oldskb))
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return;
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/* IP header checks: fragment. */
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@ -146,25 +123,6 @@ static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
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br_deliver(br_port_get_rcu(oldskb->dev), nskb);
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}
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static int nft_reject_ip6hdr_validate(struct sk_buff *oldskb)
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{
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struct ipv6hdr *hdr;
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u32 pkt_len;
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if (!pskb_may_pull(oldskb, sizeof(struct ipv6hdr)))
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return 0;
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hdr = ipv6_hdr(oldskb);
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if (hdr->version != 6)
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return 0;
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pkt_len = ntohs(hdr->payload_len);
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if (pkt_len + sizeof(struct ipv6hdr) > oldskb->len)
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return 0;
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return 1;
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}
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static void nft_reject_br_send_v6_tcp_reset(struct net *net,
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struct sk_buff *oldskb, int hook)
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{
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@ -174,7 +132,7 @@ static void nft_reject_br_send_v6_tcp_reset(struct net *net,
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unsigned int otcplen;
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struct ipv6hdr *nip6h;
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if (!nft_reject_ip6hdr_validate(oldskb))
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if (!nft_bridge_ip6hdr_validate(oldskb))
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return;
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oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
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@ -207,7 +165,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net,
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unsigned int len;
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void *payload;
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if (!nft_reject_ip6hdr_validate(oldskb))
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if (!nft_bridge_ip6hdr_validate(oldskb))
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return;
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/* Include "As much of invoking packet as possible without the ICMPv6
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