[PATCH net v5 20/21] rxrpc: only handle RESPONSE during service challenge

[David Howells <dhowells@redhat.com>]

From: Wang Jie <jiewang2024@lzu.edu.cn>

Only process RESPONSE packets while the service connection is still in
RXRPC_CONN_SERVICE_CHALLENGING. Check that state under state_lock before
running response verification and security initialization, then use a local
secured flag to decide whether to queue the secured-connection work after
the state transition. This keeps duplicate or late RESPONSE packets from
re-running the setup path and removes the unlocked post-transition state
test.

Fixes: 17926a79320a ("net: AF_RXRPC: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Jie Wang <jiewang2024@lzu.edu.cn>
Signed-off-by: Yang Yang <n05ec@lzu.edu.cn>
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: netdev@vger.kernel.org
cc: stable@kernel.org
---
 net/rxrpc/conn_event.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index c50cbfc5a313..9a41ec708aeb 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -247,6 +247,7 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 			       struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	bool secured = false;
 	int ret;
 
 	if (conn->state == RXRPC_CONN_ABORTED)
@@ -262,6 +263,13 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 		return ret;
 
 	case RXRPC_PACKET_TYPE_RESPONSE:
+		spin_lock_irq(&conn->state_lock);
+		if (conn->state != RXRPC_CONN_SERVICE_CHALLENGING) {
+			spin_unlock_irq(&conn->state_lock);
+			return 0;
+		}
+		spin_unlock_irq(&conn->state_lock);
+
 		ret = conn->security->verify_response(conn, skb);
 		if (ret < 0)
 			return ret;
@@ -272,11 +280,13 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 			return ret;
 
 		spin_lock_irq(&conn->state_lock);
-		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING)
+		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
 			conn->state = RXRPC_CONN_SERVICE;
+			secured = true;
+		}
 		spin_unlock_irq(&conn->state_lock);
 
-		if (conn->state == RXRPC_CONN_SERVICE) {
+		if (secured) {
 			/* Offload call state flipping to the I/O thread.  As
 			 * we've already received the packet, put it on the
 			 * front of the queue.