[PATCH bpf-next] xsk: Validate socket state in xsk_recvmsg, prior touching socket members

From: "Björn Töpel" <bjorn.topel@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
	magnus.karlsson@intel.com, jonathan.lemon@gmail.com,
	"kernel test robot" <oliver.sang@intel.com>
Subject: [PATCH bpf-next] xsk: Validate socket state in xsk_recvmsg, prior touching socket members
Date: Mon,  7 Dec 2020 09:20:08 +0100	[thread overview]
Message-ID: <20201207082008.132263-1-bjorn.topel@gmail.com> (raw)

From: Björn Töpel <bjorn.topel@intel.com>

In AF_XDP the socket state needs to be checked, prior touching the
members of the socket. This was not the case for the recvmsg
implementation. Fix that by moving the xsk_is_bound() call.

Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: 45a86681844e ("xsk: Add support for recvmsg()")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 net/xdp/xsk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 56c46e5f57bc..e28c6825e089 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -554,12 +554,12 @@ static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int fl
 	struct sock *sk = sock->sk;
 	struct xdp_sock *xs = xdp_sk(sk);
 
+	if (unlikely(!xsk_is_bound(xs)))
+		return -ENXIO;
 	if (unlikely(!(xs->dev->flags & IFF_UP)))
 		return -ENETDOWN;
 	if (unlikely(!xs->rx))
 		return -ENOBUFS;
-	if (unlikely(!xsk_is_bound(xs)))
-		return -ENXIO;
 	if (unlikely(need_wait))
 		return -EOPNOTSUPP;
 

base-commit: 34da87213d3ddd26643aa83deff7ffc6463da0fc
-- 
2.27.0

