Merge branch 'tcp-destroy-tcp-ao-tcp-md5-keys-in-sk_destruct'

Dmitry Safonov says:

====================
tcp: Destroy TCP-AO, TCP-MD5 keys in .sk_destruct()

On one side a minor/cosmetic issue, especially nowadays when
TCP-AO/TCP-MD5 signature verification failures aren't logged to dmesg.

Yet, I think worth addressing for two reasons:
- unsigned RST gets ignored by the peer and the connection is alive for
  longer (keep-alive interval)
- netstat counters increase and trace events report that trusted BGP peer
  is sending unsigned/incorrectly signed segments, which can ring alarm
  on monitoring.
====================

Link: https://patch.msgid.link/20250909-b4-tcp-ao-md5-rst-finwait2-v5-0-9ffaaaf8b236@arista.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

7 files changed, 45 insertions, 45 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0fb7923b8367..277914c4d067 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1941,6 +1941,7 @@ tcp_md5_do_lookup_any_l3index(const struct sock *sk,
 }
 
 #define tcp_twsk_md5_key(twsk)	((twsk)->tw_md5_key)
+void tcp_md5_destruct_sock(struct sock *sk);
 #else
 static inline struct tcp_md5sig_key *
 tcp_md5_do_lookup(const struct sock *sk, int l3index,
@@ -1957,6 +1958,9 @@ tcp_md5_do_lookup_any_l3index(const struct sock *sk,
 }
 
 #define tcp_twsk_md5_key(twsk)	NULL
+static inline void tcp_md5_destruct_sock(struct sock *sk)
+{
+}
 #endif
 
 int tcp_md5_alloc_sigpool(void);
diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h
index df655ce6987d..1e9e27d6e06b 100644
--- a/include/net/tcp_ao.h
+++ b/include/net/tcp_ao.h
@@ -130,7 +130,6 @@ struct tcp_ao_info {
 	u32			snd_sne;
 	u32			rcv_sne;
 	refcount_t		refcnt;		/* Protects twsk destruction */
-	struct rcu_head		rcu;
 };
 
 #ifdef CONFIG_TCP_MD5SIG
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9c576dc9a1f7..7f9c671b1ee0 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -412,6 +412,22 @@ static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
 	return rate64;
 }
 
+#ifdef CONFIG_TCP_MD5SIG
+void tcp_md5_destruct_sock(struct sock *sk)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (tp->md5sig_info) {
+
+		tcp_clear_md5_list(sk);
+		kfree(rcu_replace_pointer(tp->md5sig_info, NULL, 1));
+		static_branch_slow_dec_deferred(&tcp_md5_needed);
+		tcp_md5_release_sigpool();
+	}
+}
+EXPORT_IPV6_MOD_GPL(tcp_md5_destruct_sock);
+#endif
+
 /* Address-family independent initialization for a tcp_sock.
  *
  * NOTE: A lot of things set to zero explicitly by call to
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index bbb8d5f0eae7..31302be78bc4 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -268,9 +268,8 @@ static void tcp_ao_key_free_rcu(struct rcu_head *head)
 	kfree_sensitive(key);
 }
 
-static void tcp_ao_info_free_rcu(struct rcu_head *head)
+static void tcp_ao_info_free(struct tcp_ao_info *ao)
 {
-	struct tcp_ao_info *ao = container_of(head, struct tcp_ao_info, rcu);
 	struct tcp_ao_key *key;
 	struct hlist_node *n;
 
@@ -310,7 +309,7 @@ void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
 
 	if (!twsk)
 		tcp_ao_sk_omem_free(sk, ao);
-	call_rcu(&ao->rcu, tcp_ao_info_free_rcu);
+	tcp_ao_info_free(ao);
 }
 
 void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1e58a8a9ff7a..2a0602035729 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1503,9 +1503,9 @@ void tcp_clear_md5_list(struct sock *sk)
 	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
 
 	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
-		hlist_del_rcu(&key->node);
+		hlist_del(&key->node);
 		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
-		kfree_rcu(key, rcu);
+		kfree(key);
 	}
 }
 
@@ -2494,6 +2494,13 @@ static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
 	.ao_calc_key_sk		= tcp_v4_ao_calc_key_sk,
 #endif
 };
+
+static void tcp4_destruct_sock(struct sock *sk)
+{
+	tcp_md5_destruct_sock(sk);
+	tcp_ao_destroy_sock(sk, false);
+	inet_sock_destruct(sk);
+}
 #endif
 
 /* NOTE: A lot of things set to zero explicitly by call to
@@ -2509,23 +2516,12 @@ static int tcp_v4_init_sock(struct sock *sk)
 
 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
 	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
+	sk->sk_destruct = tcp4_destruct_sock;
 #endif
 
 	return 0;
 }
 
-#ifdef CONFIG_TCP_MD5SIG
-static void tcp_md5sig_info_free_rcu(struct rcu_head *head)
-{
-	struct tcp_md5sig_info *md5sig;
-
-	md5sig = container_of(head, struct tcp_md5sig_info, rcu);
-	kfree(md5sig);
-	static_branch_slow_dec_deferred(&tcp_md5_needed);
-	tcp_md5_release_sigpool();
-}
-#endif
-
 static void tcp_release_user_frags(struct sock *sk)
 {
 #ifdef CONFIG_PAGE_POOL
@@ -2562,19 +2558,6 @@ void tcp_v4_destroy_sock(struct sock *sk)
 	/* Cleans up our, hopefully empty, out_of_order_queue. */
 	skb_rbtree_purge(&tp->out_of_order_queue);
 
-#ifdef CONFIG_TCP_MD5SIG
-	/* Clean up the MD5 key list, if any */
-	if (tp->md5sig_info) {
-		struct tcp_md5sig_info *md5sig;
-
-		md5sig = rcu_dereference_protected(tp->md5sig_info, 1);
-		tcp_clear_md5_list(sk);
-		call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu);
-		rcu_assign_pointer(tp->md5sig_info, NULL);
-	}
-#endif
-	tcp_ao_destroy_sock(sk, false);
-
 	/* Clean up a referenced TCP bind bucket. */
 	if (inet_csk(sk)->icsk_bind_hash)
 		inet_put_port(sk);
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index d1c9e4088646..7c2ae07d8d5d 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -377,26 +377,17 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 }
 EXPORT_SYMBOL(tcp_time_wait);
 
-#ifdef CONFIG_TCP_MD5SIG
-static void tcp_md5_twsk_free_rcu(struct rcu_head *head)
-{
-	struct tcp_md5sig_key *key;
-
-	key = container_of(head, struct tcp_md5sig_key, rcu);
-	kfree(key);
-	static_branch_slow_dec_deferred(&tcp_md5_needed);
-	tcp_md5_release_sigpool();
-}
-#endif
-
 void tcp_twsk_destructor(struct sock *sk)
 {
 #ifdef CONFIG_TCP_MD5SIG
 	if (static_branch_unlikely(&tcp_md5_needed.key)) {
 		struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
-		if (twsk->tw_md5_key)
-			call_rcu(&twsk->tw_md5_key->rcu, tcp_md5_twsk_free_rcu);
+		if (twsk->tw_md5_key) {
+			kfree(twsk->tw_md5_key);
+			static_branch_slow_dec_deferred(&tcp_md5_needed);
+			tcp_md5_release_sigpool();
+		}
 	}
 #endif
 	tcp_ao_destroy_sock(sk, true);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0562e939b2e3..08dabc47a6e7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2110,6 +2110,13 @@ static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
 	.ao_calc_key_sk	=	tcp_v4_ao_calc_key_sk,
 #endif
 };
+
+static void tcp6_destruct_sock(struct sock *sk)
+{
+	tcp_md5_destruct_sock(sk);
+	tcp_ao_destroy_sock(sk, false);
+	inet6_sock_destruct(sk);
+}
 #endif
 
 /* NOTE: A lot of things set to zero explicitly by call to
@@ -2125,6 +2132,7 @@ static int tcp_v6_init_sock(struct sock *sk)
 
 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
 	tcp_sk(sk)->af_specific = &tcp_sock_ipv6_specific;
+	sk->sk_destruct = tcp6_destruct_sock;
 #endif
 
 	return 0;