netdev - [PATCH v3] bridge: netlink: check vlan_default

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Date:   Tue, 16 May 2017 10:48:40 +0200
From:   Tobias Jungel <tobias.jungel@...dn.de>
To:     Sabrina Dubroca <sd@...asysnail.net>,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        Stephen Hemminger <stephen@...workplumber.org>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: [PATCH v3] 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@...t ~]# ip l a type bridge
[root@...t ~]# ip l a type dummy
[root@...t ~]# ip l s bridge0 type bridge vlan_filtering 1
[root@...t ~]# ip l s bridge0 type bridge vlan_default_pvid 9999
[root@...t ~]# ip l s dummy0 master bridge0
[root@...t ~]# bridge vlan
port	vlan ids
bridge0	 9999 PVID Egress Untagged

dummy0	 9999 PVID Egress Untagged

Fixes: 0f963b7592ef ("bridge: netlink: add support for default_pvid")
Signed-off-by: Tobias Jungel <tobias.jungel@...dn.de>
---
 net/bridge/br_netlink.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index c5ce774..47cb95b 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -835,6 +835,12 @@ 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;
-- 
2.9.4