[PATCH 4.4 19/27] net: vrf: do not allow table id 0

[Greg Kroah-Hartman]

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

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

From: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>


[ Upstream commit 24c63bbc18e25d5d8439422aa5fd2d66390b88eb ]

Frank reported that vrf devices can be created with a table id of 0.
This breaks many of the run time table id checks and should not be
allowed. Detect this condition at create time and fail with EINVAL.

Fixes: 193125dbd8eb ("net: Introduce VRF device driver")
Reported-by: Frank Kellermann <frank.kellermann@xxxxxxxx>
Signed-off-by: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/vrf.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -925,6 +925,8 @@ static int vrf_newlink(struct net *src_n
 		return -EINVAL;
 
 	vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);
+	if (vrf->tb_id == RT_TABLE_UNSPEC)
+		return -EINVAL;
 
 	dev->priv_flags |= IFF_L3MDEV_MASTER;