[PATCH 4.9 51/54] 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/key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index 01d2d40ef21cb..fa475b02bdceb 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -899,7 +899,7 @@ int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
 
 	_enter("");
 
-	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
+	if (optlen <= 0 || optlen > PAGE_SIZE - 1 || rx->securities)
 		return -EINVAL;
 
 	description = memdup_user_nul(optval, optlen);
-- 
2.25.1