[PATCH 4.18 162/228] IB/hfi1: Fix SL array bounds check

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ira Weiny <ira.weiny@xxxxxxxxx>

commit 0dbfaa9f2813787679e296eb5476e40938ab48c8 upstream.

The SL specified by a user needs to be a valid SL.

Add a range check to the user specified SL value which protects from
running off the end of the SL to SC table.

CC: stable@xxxxxxxxxxxxxxx
Fixes: 7724105686e7 ("IB/hfi1: add driver files")
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/hw/hfi1/verbs.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -1590,6 +1590,7 @@ static int hfi1_check_ah(struct ib_devic
 	struct hfi1_pportdata *ppd;
 	struct hfi1_devdata *dd;
 	u8 sc5;
+	u8 sl;
 
 	if (hfi1_check_mcast(rdma_ah_get_dlid(ah_attr)) &&
 	    !(rdma_ah_get_ah_flags(ah_attr) & IB_AH_GRH))
@@ -1598,8 +1599,13 @@ static int hfi1_check_ah(struct ib_devic
 	/* test the mapping for validity */
 	ibp = to_iport(ibdev, rdma_ah_get_port_num(ah_attr));
 	ppd = ppd_from_ibp(ibp);
-	sc5 = ibp->sl_to_sc[rdma_ah_get_sl(ah_attr)];
 	dd = dd_from_ppd(ppd);
+
+	sl = rdma_ah_get_sl(ah_attr);
+	if (sl >= ARRAY_SIZE(ibp->sl_to_sc))
+		return -EINVAL;
+
+	sc5 = ibp->sl_to_sc[sl];
 	if (sc_to_vlt(dd, sc5) > num_vls && sc_to_vlt(dd, sc5) != 0xf)
 		return -EINVAL;
 	return 0;