[PATCH 4.4 38/39] rxrpc: Fix server keyring leak

[Greg Kroah-Hartman]

From: David Howells <dhowells@xxxxxxxxxx>

[ Upstream commit 38b1dc47a35ba14c3f4472138ea56d014c2d609b ]

If someone calls setsockopt() twice to set a server key keyring, the first
keyring is leaked.

Fix it to return an error instead if the server key keyring is already set.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/rxrpc/ar-key.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/rxrpc/ar-key.c
+++ b/net/rxrpc/ar-key.c
@@ -897,7 +897,7 @@ int rxrpc_request_key(struct rxrpc_sock
 
 	_enter("");
 
-	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
+	if (optlen <= 0 || optlen > PAGE_SIZE - 1 || rx->securities)
 		return -EINVAL;
 
 	description = kmalloc(optlen + 1, GFP_KERNEL);