[PATCH 5.15.y] rxrpc: only handle RESPONSE during service challenge

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit c43ffdcfdbb5567b1f143556df8a04b4eeea041c ]

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 ("[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: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: stable@kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-21-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ adapted to spin_lock_bh usage, 3-arg verify_response(), and direct rxrpc_call_is_secure() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/rxrpc/conn_event.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 5d91ef562ff78..293922df2a891 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -293,6 +293,7 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 			       u32 *_abort_code)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	bool secured = false;
 	__be32 wtmp;
 	u32 abort_code;
 	int loop, ret;
@@ -337,6 +338,13 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 							    _abort_code);
 
 	case RXRPC_PACKET_TYPE_RESPONSE:
+		spin_lock_bh(&conn->state_lock);
+		if (conn->state != RXRPC_CONN_SERVICE_CHALLENGING) {
+			spin_unlock_bh(&conn->state_lock);
+			return 0;
+		}
+		spin_unlock_bh(&conn->state_lock);
+
 		ret = conn->security->verify_response(conn, skb, _abort_code);
 		if (ret < 0)
 			return ret;
@@ -348,17 +356,18 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 
 		spin_lock(&conn->bundle->channel_lock);
 		spin_lock_bh(&conn->state_lock);
-
 		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
 			conn->state = RXRPC_CONN_SERVICE;
-			spin_unlock_bh(&conn->state_lock);
+			secured = true;
+		}
+		spin_unlock_bh(&conn->state_lock);
+
+		if (secured) {
 			for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
 				rxrpc_call_is_secure(
 					rcu_dereference_protected(
 						conn->channels[loop].call,
 						lockdep_is_held(&conn->bundle->channel_lock)));
-		} else {
-			spin_unlock_bh(&conn->state_lock);
 		}
 
 		spin_unlock(&conn->bundle->channel_lock);
-- 
2.53.0