| From 8f9058d6fc2cbb1dbeae282265c8f3e64e54cbea Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 28 Aug 2018 14:45:30 +0300 |
| Subject: IB/ipoib: Ensure that MTU isn't less than minimum permitted |
| |
| From: Muhammad Sammar <muhammads@mellanox.com> |
| |
| [ Upstream commit 142a9c287613560edf5a03c8d142c8b6ebc1995b ] |
| |
| 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 <muhammads@mellanox.com> |
| Reviewed-by: Feras Daoud <ferasda@mellanox.com> |
| Signed-off-by: Leon Romanovsky <leonro@mellanox.com> |
| Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/infiniband/ulp/ipoib/ipoib_main.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c |
| index 78dd36daac00e..d8cb5bbe6eb58 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; |
| -- |
| 2.20.1 |
| |
