diff options
| author | Florian Westphal <fw@strlen.de> | 2023-02-01 14:45:22 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2023-02-17 13:04:56 +0100 |
| commit | 2954fe60e33da0f4de4d81a4c95c7dddb517d00c (patch) | |
| tree | dc62dd7ec9f19796605a78780e4ca0075f12446a /include/linux/netfilter.h | |
| parent | e4d0fe71f59dc5137a2793ff7560730d80d1e1f4 (diff) | |
netfilter: let reset rules clean out conntrack entries
iptables/nftables support responding to tcp packets with tcp resets.
The generated tcp reset packet passes through both output and postrouting
netfilter hooks, but conntrack will never see them because the generated
skb has its ->nfct pointer copied over from the packet that triggered the
reset rule.
If the reset rule is used for established connections, this
may result in the conntrack entry to be around for a very long
time (default timeout is 5 days).
One way to avoid this would be to not copy the nf_conn pointer
so that the rest packet passes through conntrack too.
Problem is that output rules might not have the same conntrack
zone setup as the prerouting ones, so its possible that the
reset skb won't find the correct entry. Generating a template
entry for the skb seems error prone as well.
Add an explicit "closing" function that switches a confirmed
conntrack entry to closed state and wire this up for tcp.
If the entry isn't confirmed, no action is needed because
the conntrack entry will never be committed to the table.
Reported-by: Russel King <linux@armlinux.org.uk>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/linux/netfilter.h')
| -rw-r--r-- | include/linux/netfilter.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index d8817d381c14..6863e271a9de 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -437,11 +437,13 @@ nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) #include <linux/netfilter/nf_conntrack_zones_common.h> void nf_ct_attach(struct sk_buff *, const struct sk_buff *); +void nf_ct_set_closing(struct nf_conntrack *nfct); struct nf_conntrack_tuple; bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, const struct sk_buff *skb); #else static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} +static inline void nf_ct_set_closing(struct nf_conntrack *nfct) {} struct nf_conntrack_tuple; static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, const struct sk_buff *skb) @@ -459,6 +461,7 @@ struct nf_ct_hook { bool (*get_tuple_skb)(struct nf_conntrack_tuple *, const struct sk_buff *); void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb); + void (*set_closing)(struct nf_conntrack *nfct); }; extern const struct nf_ct_hook __rcu *nf_ct_hook; |