[PATCH AUTOSEL for 4.15 067/189] RDMA/cma: Check existence of netdevice during port validation

[Sasha Levin]

From: Parav Pandit <parav@xxxxxxxxxxxx>

[ Upstream commit 00db63c128dd3daf38f481371976c24d32678142 ]

If valid netdevice is not found for RoCE, GID table should not be
searched with NULL netdevice.

Doing so causes the search routines to ignore the netdev argument and may
match the wrong GID table entry if the netdev is deleted.

Fixes: abae1b71dd37 ("IB/cma: cma_validate_port should verify the port and netdevice")
Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx>
Reviewed-by: Mark Bloch <markb@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/infiniband/core/cma.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 67aece2f5d8d..6958df862591 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -624,11 +624,13 @@ static inline int cma_validate_port(struct ib_device *device, u8 port,
 	if ((dev_type != ARPHRD_INFINIBAND) && rdma_protocol_ib(device, port))
 		return ret;
 
-	if (dev_type == ARPHRD_ETHER && rdma_protocol_roce(device, port))
+	if (dev_type == ARPHRD_ETHER && rdma_protocol_roce(device, port)) {
 		ndev = dev_get_by_index(&init_net, bound_if_index);
-	else
+		if (!ndev)
+			return ret;
+	} else {
 		gid_type = IB_GID_TYPE_IB;
-
+	}
 
 	ret = ib_find_cached_gid_by_port(device, gid, gid_type, port,
 					 ndev, NULL);
-- 
2.15.1