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net/tcp: Don't consider TCP_CLOSE in TCP_AO_ESTABLISHED

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TCP_CLOSE may or may not have current/rnext keys and should not be
considered "established". The fast-path for TCP_CLOSE is
SKB_DROP_REASON_TCP_CLOSE. This is what tcp_rcv_state_process() does
anyways. Add an early drop path to not spend any time verifying
segment signatures for sockets in TCP_CLOSE state.

Cc: stable@vger.kernel.org # v6.7
Fixes: 0a3a809089 ("net/tcp: Verify inbound TCP-AO signed segments")
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://lore.kernel.org/r/20240529-tcp_ao-sk_state-v1-1-d69b5d323c52@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Dmitry Safonov 2024-05-29 18:29:32 +01:00 committed by Jakub Kicinski
parent e85e271dec
commit 33700a0c9b
2 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/net/tcp_ao.h
View File

@ -86,7 +86,8 @@ static inline int tcp_ao_sizeof_key(const struct tcp_ao_key *key)
struct tcp_ao_info {
/* List of tcp_ao_key's */
struct hlist_head head;
/* current_key and rnext_key aren't maintained on listen sockets.
/* current_key and rnext_key are maintained on sockets
* in TCP_AO_ESTABLISHED states.
* Their purpose is to cache keys on established connections,
* saving needless lookups. Never dereference any of them from
* listen sockets.
@ -201,9 +202,9 @@ struct tcp6_ao_context {
};
struct tcp_sigpool;
/* Established states are fast-path and there always is current_key/rnext_key */
#define TCP_AO_ESTABLISHED (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | \
TCPF_CLOSE | TCPF_CLOSE_WAIT | \
TCPF_LAST_ACK | TCPF_CLOSING)
TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSING)
int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
struct tcp_ao_key *key, struct tcphdr *th,

13
net/ipv4/tcp_ao.c
View File

@ -933,6 +933,7 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
struct tcp_ao_key *key;
__be32 sisn, disn;
u8 *traffic_key;
int state;
u32 sne = 0;
info = rcu_dereference(tcp_sk(sk)->ao_info);
@ -948,8 +949,9 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
disn = 0;
}
state = READ_ONCE(sk->sk_state);
/* Fast-path */
if (likely((1 << sk->sk_state) & TCP_AO_ESTABLISHED)) {
if (likely((1 << state) & TCP_AO_ESTABLISHED)) {
enum skb_drop_reason err;
struct tcp_ao_key *current_key;
@ -988,6 +990,9 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
return SKB_NOT_DROPPED_YET;
}
if (unlikely(state == TCP_CLOSE))
return SKB_DROP_REASON_TCP_CLOSE;
/* Lookup key based on peer address and keyid.
* current_key and rnext_key must not be used on tcp listen
* sockets as otherwise:
@ -1001,7 +1006,7 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
if (th->syn && !th->ack)
goto verify_hash;
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) {
if ((1 << state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) {
/* Make the initial syn the likely case here */
if (unlikely(req)) {
sne = tcp_ao_compute_sne(0, tcp_rsk(req)->rcv_isn,
@ -1018,14 +1023,14 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
/* no way to figure out initial sisn/disn - drop */
return SKB_DROP_REASON_TCP_FLAGS;
}
} else if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
} else if ((1 << state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
disn = info->lisn;
if (th->syn || th->rst)
sisn = th->seq;
else
sisn = info->risn;
} else {
WARN_ONCE(1, "TCP-AO: Unexpected sk_state %d", sk->sk_state);
WARN_ONCE(1, "TCP-AO: Unexpected sk_state %d", state);
return SKB_DROP_REASON_TCP_AOFAILURE;
}
verify_hash: