bridge: netlink: check vlan_default_pvid range

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@cumulusnetworks.com>
Signed-off-by: Tobias Jungel <tobias.jungel@bisdn.de>
Acked-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index c5ce7745b230..574f78824d8a 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -835,6 +835,13 @@ static int br_validate(struct nlattr *tb[], struct nlattr *data[])
                         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;