From eb9c7ebe6980c41cf6ae889e301c3b49f473ee9f Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Fri, 6 Jan 2006 23:06:30 -0800 Subject: [PATCH] [NETFILTER]: Handle NAT in IPsec policy checks Handle NAT of decapsulated IPsec packets by reconstructing the struct flowi of the original packet from the conntrack information for IPsec policy checks. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/netfilter.h | 16 +++++++++ net/dccp/ipv4.c | 2 +- net/ipv4/netfilter.c | 3 ++ net/ipv4/netfilter/ip_nat_standalone.c | 50 ++++++++++++++++++++++++-- net/xfrm/xfrm_policy.c | 2 ++ 5 files changed, 70 insertions(+), 3 deletions(-) diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 79bb977afe..84506dfa1f 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -274,6 +274,20 @@ struct nf_queue_rerouter { extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer); extern int nf_unregister_queue_rerouter(int pf); +#include +extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); + +static inline void +nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) +{ +#ifdef CONFIG_IP_NF_NAT_NEEDED + void (*decodefn)(struct sk_buff *, struct flowi *); + + if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL) + decodefn(skb, fl); +#endif +} + #ifdef CONFIG_PROC_FS #include extern struct proc_dir_entry *proc_net_netfilter; @@ -282,6 +296,8 @@ extern struct proc_dir_entry *proc_net_netfilter; #else /* !CONFIG_NETFILTER */ #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} +static inline void +nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {} #endif /*CONFIG_NETFILTER*/ #endif /*__KERNEL__*/ diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index 23ba177c11..00f9832266 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -986,6 +986,7 @@ int dccp_v4_rcv(struct sk_buff *skb) if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse; + nf_reset(skb); return sk_receive_skb(sk, skb); @@ -1099,7 +1100,6 @@ int dccp_v4_destroy_sock(struct sock *sk) kfree_skb(sk->sk_send_head); sk->sk_send_head = NULL; } - nf_reset(skb); /* Clean up a referenced DCCP bind bucket. */ if (inet_csk(sk)->icsk_bind_hash != NULL) diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c index 4c637a1cbd..3321092b09 100644 --- a/net/ipv4/netfilter.c +++ b/net/ipv4/netfilter.c @@ -86,6 +86,9 @@ int ip_route_me_harder(struct sk_buff **pskb) } EXPORT_SYMBOL(ip_route_me_harder); +void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); +EXPORT_SYMBOL(ip_nat_decode_session); + /* * Extra routing may needed on local out, as the QUEUE target never * returns control to the table. diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c index b518697af4..8b8a1f00bb 100644 --- a/net/ipv4/netfilter/ip_nat_standalone.c +++ b/net/ipv4/netfilter/ip_nat_standalone.c @@ -55,6 +55,44 @@ : ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN" \ : "*ERROR*"))) +#ifdef CONFIG_XFRM +static void nat_decode_session(struct sk_buff *skb, struct flowi *fl) +{ + struct ip_conntrack *ct; + struct ip_conntrack_tuple *t; + enum ip_conntrack_info ctinfo; + enum ip_conntrack_dir dir; + unsigned long statusbit; + + ct = ip_conntrack_get(skb, &ctinfo); + if (ct == NULL) + return; + dir = CTINFO2DIR(ctinfo); + t = &ct->tuplehash[dir].tuple; + + if (dir == IP_CT_DIR_ORIGINAL) + statusbit = IPS_DST_NAT; + else + statusbit = IPS_SRC_NAT; + + if (ct->status & statusbit) { + fl->fl4_dst = t->dst.ip; + if (t->dst.protonum == IPPROTO_TCP || + t->dst.protonum == IPPROTO_UDP) + fl->fl_ip_dport = t->dst.u.tcp.port; + } + + statusbit ^= IPS_NAT_MASK; + + if (ct->status & statusbit) { + fl->fl4_src = t->src.ip; + if (t->dst.protonum == IPPROTO_TCP || + t->dst.protonum == IPPROTO_UDP) + fl->fl_ip_sport = t->src.u.tcp.port; + } +} +#endif + static unsigned int ip_nat_fn(unsigned int hooknum, struct sk_buff **pskb, @@ -330,10 +368,14 @@ static int init_or_cleanup(int init) if (!init) goto cleanup; +#ifdef CONFIG_XFRM + BUG_ON(ip_nat_decode_session != NULL); + ip_nat_decode_session = nat_decode_session; +#endif ret = ip_nat_rule_init(); if (ret < 0) { printk("ip_nat_init: can't setup rules.\n"); - goto cleanup_nothing; + goto cleanup_decode_session; } ret = nf_register_hook(&ip_nat_in_ops); if (ret < 0) { @@ -381,7 +423,11 @@ static int init_or_cleanup(int init) nf_unregister_hook(&ip_nat_in_ops); cleanup_rule_init: ip_nat_rule_cleanup(); - cleanup_nothing: + cleanup_decode_session: +#ifdef CONFIG_XFRM + ip_nat_decode_session = NULL; + synchronize_net(); +#endif return ret; } diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index f2edc9225b..59614a994b 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -985,6 +986,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, if (xfrm_decode_session(skb, &fl, family) < 0) return 0; + nf_nat_decode_session(skb, &fl, family); sk_sid = security_sk_sid(sk, &fl, fl_dir); -- 2.39.5