[PATCH 4.19 001/106] ipv6: Consider sk_bound_dev_if when binding a socket to a v4 mapped address

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Ahern <dsahern@xxxxxxxxx>

[ Upstream commit ec90ad334986fa5856d11dd272f7f22fa86c55c4 ]

Similar to c5ee066333eb ("ipv6: Consider sk_bound_dev_if when binding a
socket to an address"), binding a socket to v4 mapped addresses needs to
consider if the socket is bound to a device.

This problem also exists from the beginning of git history.

Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/af_inet6.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -309,6 +309,7 @@ static int __inet6_bind(struct sock *sk,
 
 	/* Check if the address belongs to the host. */
 	if (addr_type == IPV6_ADDR_MAPPED) {
+		struct net_device *dev = NULL;
 		int chk_addr_ret;
 
 		/* Binding to v4-mapped address on a v6-only socket
@@ -319,9 +320,17 @@ static int __inet6_bind(struct sock *sk,
 			goto out;
 		}
 
+		if (sk->sk_bound_dev_if) {
+			dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
+			if (!dev) {
+				err = -ENODEV;
+				goto out;
+			}
+		}
+
 		/* Reproduce AF_INET checks to make the bindings consistent */
 		v4addr = addr->sin6_addr.s6_addr32[3];
-		chk_addr_ret = inet_addr_type(net, v4addr);
+		chk_addr_ret = inet_addr_type_dev_table(net, dev, v4addr);
 		if (!inet_can_nonlocal_bind(net, inet) &&
 		    v4addr != htonl(INADDR_ANY) &&
 		    chk_addr_ret != RTN_LOCAL &&