From 142a9c287613560edf5a03c8d142c8b6ebc1995b Mon Sep 17 00:00:00 2001 From: Muhammad Sammar Date: Tue, 28 Aug 2018 14:45:30 +0300 Subject: IB/ipoib: Ensure that MTU isn't less than minimum permitted It is illegal to change MTU to a value lower than the minimum MTU stated in ethernet spec. In addition to that we need to add 4 bytes for encapsulation header (IPOIB_ENCAP_LEN). Before "ifconfig ib0 mtu 0" command, succeeds while it obviously shouldn't. Signed-off-by: Muhammad Sammar Reviewed-by: Feras Daoud Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe --- drivers/infiniband/ulp/ipoib/ipoib_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/infiniband/ulp/ipoib/ipoib_main.c') diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c index e3d28f9ad9c0..2d20de72e67f 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c @@ -243,7 +243,8 @@ static int ipoib_change_mtu(struct net_device *dev, int new_mtu) return 0; } - if (new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu)) + if (new_mtu < (ETH_MIN_MTU + IPOIB_ENCAP_LEN) || + new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu)) return -EINVAL; priv->admin_mtu = new_mtu; -- cgit v1.2.3