From: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
commit 33700a0c9b562700c28d31360a5f04508f459a45 upstream.
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@xxxxxxxxxxxxxxx # v6.7
Fixes: 0a3a809089eb ("net/tcp: Verify inbound TCP-AO signed segments")
Signed-off-by: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240529-tcp_ao-sk_state-v1-1-d69b5d323c52@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/tcp_ao.h | 7 ++++---
net/ipv4/tcp_ao.c | 13 +++++++++----
2 files changed, 13 insertions(+), 7 deletions(-)
--- a/include/net/tcp_ao.h
+++ b/include/net/tcp_ao.h
@@ -86,7 +86,8 @@ static inline int tcp_ao_sizeof_key(cons
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,
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -933,6 +933,7 @@ tcp_inbound_ao_hash(struct sock *sk, con
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, con
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, con
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, con
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, con
/* 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:
Patches currently in stable-queue which might be from 0x7f454c46@xxxxxxxxx are
queue-6.9/net-tcp-don-t-consider-tcp_close-in-tcp_ao_established.patch
