| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 097/205] IB/ipoib: Ensure that MTU isn't less than minimum permitted | Date | Fri, 8 Nov 2019 06:36:04 -0500 |
| |
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
|