[PATCH 5.10.y] rxrpc: fix reference count leak in rxrpc_server_keyring()

[Sasha Levin]

From: Luxiao Xu <rakukuip at gmail.com>

[ Upstream commit f125846ee79fcae537a964ce66494e96fa54a6de ]

This patch fixes a reference count leak in rxrpc_server_keyring()
by checking if rx->securities is already set.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: Yifan Wu <yifanwucs at gmail.com>
Reported-by: Juefei Pu <tomapufckgml at gmail.com>
Co-developed-by: Yuan Tan <yuantan098 at gmail.com>
Signed-off-by: Yuan Tan <yuantan098 at gmail.com>
Suggested-by: Xin Liu <bird at lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z at gmail.com>
Signed-off-by: Luxiao Xu <rakukuip at gmail.com>
Signed-off-by: Ren Wei <n05ec at lzu.edu.cn>
Signed-off-by: David Howells <dhowells at redhat.com>
cc: Marc Dionne <marc.dionne at auristor.com>
cc: Simon Horman <horms at kernel.org>
cc: linux-afs at lists.infradead.org
cc: stable at kernel.org
Link: https://patch.msgid.link/20260408121252.2249051-15-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba at kernel.org>
[ applied patch to net/rxrpc/key.c instead of net/rxrpc/server_key.c ]
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 net/rxrpc/key.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index 979338a64c0ca..0144155d02e05 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -933,6 +933,9 @@ int rxrpc_server_keyring(struct rxrpc_sock *rx, sockptr_t optval, int optlen)
 
 	_enter("");
 
+	if (rx->securities)
+		return -EINVAL;
+
 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
 		return -EINVAL;
 
-- 
2.53.0