[PATCH net v2 07/10] rxrpc: Fix oob challenge leak in cleanup after notification failure

[David Howells <dhowells@redhat.com>]

Fix rxrpc_notify_socket_oob() to return an indication of failure in the
event that it failed to queue a packet and fix rxrpc_post_challenge() to
clean up the connection ref in such an event.

Fixes: 5800b1cf3fd8 ("rxrpc: Allow CHALLENGEs to the passed to the app for a RESPONSE")
Link: https://sashiko.dev/#/patchset/20260616155749.2125907-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jeffrey Altman <jaltman@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
---
 net/rxrpc/ar-internal.h | 4 ++--
 net/rxrpc/conn_event.c  | 9 +++++++--
 net/rxrpc/oob.c         | 7 +++++--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 98f2165159d7..ead3419f08b7 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -1355,9 +1355,9 @@ static inline struct rxrpc_net *rxrpc_net(struct net *net)
 }
 
 /*
- * out_of_band.c
+ * oob.c
  */
-void rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb);
+bool rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb);
 void rxrpc_add_pending_oob(struct rxrpc_sock *rx, struct sk_buff *skb);
 int rxrpc_sendmsg_oob(struct rxrpc_sock *rx, struct msghdr *msg, size_t len);
 
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index c96ca615b787..611c790bc6d0 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -436,7 +436,7 @@ static bool rxrpc_post_challenge(struct rxrpc_connection *conn,
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct rxrpc_call *call = NULL;
 	struct rxrpc_sock *rx;
-	bool respond = false;
+	bool respond = false, queued = false;
 
 	sp->chall.conn =
 		rxrpc_get_connection(conn, rxrpc_conn_get_challenge_input);
@@ -472,8 +472,13 @@ static bool rxrpc_post_challenge(struct rxrpc_connection *conn,
 	}
 
 	if (call)
-		rxrpc_notify_socket_oob(call, skb);
+		queued = rxrpc_notify_socket_oob(call, skb);
 	rcu_read_unlock();
+	if (call && !queued) {
+		rxrpc_put_connection(conn, rxrpc_conn_put_challenge_input);
+		sp->chall.conn = NULL;
+		return false;
+	}
 
 	if (!call)
 		rxrpc_post_packet_to_conn(conn, skb);
diff --git a/net/rxrpc/oob.c b/net/rxrpc/oob.c
index 3318c8bd82ad..c80ee2487d09 100644
--- a/net/rxrpc/oob.c
+++ b/net/rxrpc/oob.c
@@ -32,11 +32,12 @@ struct rxrpc_oob_params {
  * Post an out-of-band message for attention by the socket or kernel service
  * associated with a reference call.
  */
-void rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb)
+bool rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct rxrpc_sock *rx;
 	struct sock *sk;
+	bool queued = false;
 
 	rcu_read_lock();
 
@@ -49,6 +50,7 @@ void rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb)
 			skb->skb_mstamp_ns = rx->oob_id_counter++;
 			rxrpc_get_skb(skb, rxrpc_skb_get_post_oob);
 			skb_queue_tail(&rx->recvmsg_oobq, skb);
+			queued = true;
 
 			trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial);
 			if (rx->app_ops)
@@ -56,11 +58,12 @@ void rxrpc_notify_socket_oob(struct rxrpc_call *call, struct sk_buff *skb)
 		}
 
 		spin_unlock_irq(&rx->recvmsg_lock);
-		if (!rx->app_ops && !sock_flag(sk, SOCK_DEAD))
+		if (queued && !rx->app_ops && !sock_flag(sk, SOCK_DEAD))
 			sk->sk_data_ready(sk);
 	}
 
 	rcu_read_unlock();
+	return queued;
 }
 
 /*