[PATCH 4.19 030/220] IB/hfi1: Ensure ucast_dlid access doesnt exceed bounds

[Greg Kroah-Hartman]

From: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>

[ Upstream commit 3144533bf667c8e53bb20656b78295960073e57b ]

The dlid assignment made by looking into the u_ucast_dlid array does not
do an explicit check for the size of the array. The code path to arrive at
def_port, the index value is long and complicated so its best to just have
an explicit check here.

Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
index 267da8215e08f..31cd361416ac9 100644
--- a/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
+++ b/drivers/infiniband/ulp/opa_vnic/opa_vnic_encap.c
@@ -351,7 +351,8 @@ static uint32_t opa_vnic_get_dlid(struct opa_vnic_adapter *adapter,
 			if (unlikely(!dlid))
 				v_warn("Null dlid in MAC address\n");
 		} else if (def_port != OPA_VNIC_INVALID_PORT) {
-			dlid = info->vesw.u_ucast_dlid[def_port];
+			if (def_port < OPA_VESW_MAX_NUM_DEF_PORT)
+				dlid = info->vesw.u_ucast_dlid[def_port];
 		}
 	}
 
-- 
2.20.1