[PATCH net v4 15/15] rxrpc: fix reference count leak in rxrpc_server_keyring()

[David Howells <dhowells@redhat.com>]

From: Luxiao Xu <rakukuip@gmail.com>

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@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>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@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/server_key.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/rxrpc/server_key.c b/net/rxrpc/server_key.c
index 36b05fd842a7..d4777851079f 100644
--- a/net/rxrpc/server_key.c
+++ b/net/rxrpc/server_key.c
@@ -125,6 +125,9 @@ int rxrpc_server_keyring(struct rxrpc_sock *rx, sockptr_t optval, int optlen)
 
 	_enter("");
 
+	if (rx->securities)
+		return -EEXIST;
+
 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
 		return -EINVAL;