From: Muhammad Sammar <muhammads@mellanox.com>
Date: Tue, 28 Aug 2018 14:45:30 +0300
Subject: IB/ipoib: Ensure that MTU isn't less than minimum permitted
Patch-mainline: v4.20-rc1
Git-commit: 142a9c287613560edf5a03c8d142c8b6ebc1995b
References: bsc#1103992 FATE#326009
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/ulp/ipoib/ipoib_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 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_d
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;