[PATCH 4.9 21/94] bridge: netlink: check vlan_default_pvid range

[Greg Kroah-Hartman]

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

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

From: Tobias Jungel <tobias.jungel@xxxxxxxx>


[ Upstream commit a285860211bf257b0e6d522dac6006794be348af ]

Currently it is allowed to set the default pvid of a bridge to a value
above VLAN_VID_MASK (0xfff). This patch adds a check to br_validate and
returns -EINVAL in case the pvid is out of bounds.

Reproduce by calling:

[root@test ~]# ip l a type bridge
[root@test ~]# ip l a type dummy
[root@test ~]# ip l s bridge0 type bridge vlan_filtering 1
[root@test ~]# ip l s bridge0 type bridge vlan_default_pvid 9999
[root@test ~]# ip l s dummy0 master bridge0
[root@test ~]# bridge vlan
port	vlan ids
bridge0	 9999 PVID Egress Untagged

dummy0	 9999 PVID Egress Untagged

Fixes: 0f963b7592ef ("bridge: netlink: add support for default_pvid")
Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tobias Jungel <tobias.jungel@xxxxxxxx>
Acked-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/bridge/br_netlink.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -776,6 +776,13 @@ static int br_validate(struct nlattr *tb
 			return -EPROTONOSUPPORT;
 		}
 	}
+
+	if (data[IFLA_BR_VLAN_DEFAULT_PVID]) {
+		__u16 defpvid = nla_get_u16(data[IFLA_BR_VLAN_DEFAULT_PVID]);
+
+		if (defpvid >= VLAN_VID_MASK)
+			return -EINVAL;
+	}
 #endif
 
 	return 0;