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Message-ID: <20231121020111.1143180-8-dima@arista.com>
Date: Tue, 21 Nov 2023 02:01:11 +0000
From: Dmitry Safonov <dima@...sta.com>
To: David Ahern <dsahern@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>
Cc: linux-kernel@...r.kernel.org,
Dmitry Safonov <dima@...sta.com>,
Dmitry Safonov <0x7f454c46@...il.com>,
Francesco Ruggeri <fruggeri05@...il.com>,
Salam Noureddine <noureddine@...sta.com>,
Simon Horman <horms@...nel.org>,
netdev@...r.kernel.org
Subject: [PATCH 7/7] net/tcp: Don't store TCP-AO maclen on reqsk
This extra check doesn't work for a handshake when SYN segment has
(current_key.maclen != rnext_key.maclen). It could be amended to
preserve rnext_key.maclen instead of current_key.maclen, but that
requires a lookup on listen socket.
Originally, this extra maclen check was introduced just because it was
cheap. Drop it and convert tcp_request_sock::maclen into boolean
tcp_request_sock::used_tcp_ao.
Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets")
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
include/linux/tcp.h | 10 ++++------
net/ipv4/tcp_ao.c | 4 ++--
net/ipv4/tcp_input.c | 5 +++--
net/ipv4/tcp_output.c | 9 +++------
4 files changed, 12 insertions(+), 16 deletions(-)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 68f3d315d2e1..3af897b00920 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -155,6 +155,9 @@ struct tcp_request_sock {
bool req_usec_ts;
#if IS_ENABLED(CONFIG_MPTCP)
bool drop_req;
+#endif
+#ifdef CONFIG_TCP_AO
+ bool used_tcp_ao;
#endif
u32 txhash;
u32 rcv_isn;
@@ -169,7 +172,6 @@ struct tcp_request_sock {
#ifdef CONFIG_TCP_AO
u8 ao_keyid;
u8 ao_rcv_next;
- u8 maclen;
#endif
};
@@ -180,14 +182,10 @@ static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
static inline bool tcp_rsk_used_ao(const struct request_sock *req)
{
- /* The real length of MAC is saved in the request socket,
- * signing anything with zero-length makes no sense, so here is
- * a little hack..
- */
#ifndef CONFIG_TCP_AO
return false;
#else
- return tcp_rsk(req)->maclen != 0;
+ return tcp_rsk(req)->used_tcp_ao;
#endif
}
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index 9b7f1970c2e9..07221319e8c5 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -851,7 +851,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
const struct tcp_ao_hdr *aoh;
struct tcp_ao_key *key;
- treq->maclen = 0;
+ treq->used_tcp_ao = false;
if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh)
return;
@@ -863,7 +863,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
treq->ao_rcv_next = aoh->keyid;
treq->ao_keyid = aoh->rnext_keyid;
- treq->maclen = tcp_ao_maclen(key);
+ treq->used_tcp_ao = true;
}
static enum skb_drop_reason
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 78896c8be0d4..89cb6912dd91 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -7182,11 +7182,12 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
goto drop_and_release; /* Invalid TCP options */
if (aoh) {
- tcp_rsk(req)->maclen = aoh->length - sizeof(struct tcp_ao_hdr);
+ tcp_rsk(req)->used_tcp_ao = true;
tcp_rsk(req)->ao_rcv_next = aoh->keyid;
tcp_rsk(req)->ao_keyid = aoh->rnext_keyid;
+
} else {
- tcp_rsk(req)->maclen = 0;
+ tcp_rsk(req)->used_tcp_ao = false;
}
#endif
tcp_rsk(req)->snt_isn = isn;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 93eef1dbbc55..f5ef15e1d9ac 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3720,7 +3720,6 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
if (tcp_rsk_used_ao(req)) {
#ifdef CONFIG_TCP_AO
struct tcp_ao_key *ao_key = NULL;
- u8 maclen = tcp_rsk(req)->maclen;
u8 keyid = tcp_rsk(req)->ao_keyid;
ao_key = tcp_sk(sk)->af_specific->ao_lookup(sk, req_to_sk(req),
@@ -3730,13 +3729,11 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
* for another peer-matching key, but the peer has requested
* ao_keyid (RFC5925 RNextKeyID), so let's keep it simple here.
*/
- if (unlikely(!ao_key || tcp_ao_maclen(ao_key) != maclen)) {
- u8 key_maclen = ao_key ? tcp_ao_maclen(ao_key) : 0;
-
+ if (unlikely(!ao_key)) {
rcu_read_unlock();
kfree_skb(skb);
- net_warn_ratelimited("TCP-AO: the keyid %u with maclen %u|%u from SYN packet is not present - not sending SYNACK\n",
- keyid, maclen, key_maclen);
+ net_warn_ratelimited("TCP-AO: the keyid %u from SYN packet is not present - not sending SYNACK\n",
+ keyid);
return NULL;
}
key.ao_key = ao_key;
--
2.42.0
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