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-rw-r--r--Documentation/networking/af_xdp.rst9
-rw-r--r--net/xdp/xsk.c5
2 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst
index 60b217b436be..5b77b9e5ac7e 100644
--- a/Documentation/networking/af_xdp.rst
+++ b/Documentation/networking/af_xdp.rst
@@ -433,6 +433,15 @@ start N bytes into the buffer leaving the first N bytes for the
 application to use. The final option is the flags field, but it will
 be dealt with in separate sections for each UMEM flag.
 
+SO_BINDTODEVICE setsockopt
+--------------------------
+
+This is a generic SOL_SOCKET option that can be used to tie AF_XDP
+socket to a particular network interface.  It is useful when a socket
+is created by a privileged process and passed to a non-privileged one.
+Once the option is set, kernel will refuse attempts to bind that socket
+to a different interface.  Updating the value requires CAP_NET_RAW.
+
 XDP_STATISTICS getsockopt
 -------------------------
 
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 13f62d2402e7..371d269d22fa 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -886,6 +886,7 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 	struct sock *sk = sock->sk;
 	struct xdp_sock *xs = xdp_sk(sk);
 	struct net_device *dev;
+	int bound_dev_if;
 	u32 flags, qid;
 	int err = 0;
 
@@ -899,6 +900,10 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 		      XDP_USE_NEED_WAKEUP))
 		return -EINVAL;
 
+	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
+	if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex)
+		return -EINVAL;
+
 	rtnl_lock();
 	mutex_lock(&xs->mutex);
 	if (xs->state != XSK_READY) {