[PATCH AUTOSEL 4.19 013/172] scsi: qedi: Check for buffer overflow in qedi_set_path()

[Sasha Levin]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit 4a4c0cfb4be74e216dd4446b254594707455bfc6 ]

Smatch complains that the "path_data->handle" variable is user controlled.
It comes from iscsi_set_path() so that seems possible.  It's harmless to
add a limit check.

The qedi->ep_tbl[] array has qedi->max_active_conns elements (which is
always ISCSI_MAX_SESS_PER_HBA (4096) elements).  The array is allocated in
the qedi_cm_alloc_mem() function.

Link: https://lore.kernel.org/r/20200428131939.GA696531@mwanda
Fixes: ace7f46ba5fd ("scsi: qedi: Add QLogic FastLinQ offload iSCSI driver framework.")
Acked-by: Manish Rangankar <mrangankar@xxxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/qedi/qedi_iscsi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
index 1b7049dce169..d59473d1679f 100644
--- a/drivers/scsi/qedi/qedi_iscsi.c
+++ b/drivers/scsi/qedi/qedi_iscsi.c
@@ -1217,6 +1217,10 @@ static int qedi_set_path(struct Scsi_Host *shost, struct iscsi_path *path_data)
 	}
 
 	iscsi_cid = (u32)path_data->handle;
+	if (iscsi_cid >= qedi->max_active_conns) {
+		ret = -EINVAL;
+		goto set_path_exit;
+	}
 	qedi_ep = qedi->ep_tbl[iscsi_cid];
 	QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_INFO,
 		  "iscsi_cid=0x%x, qedi_ep=%p\n", iscsi_cid, qedi_ep);
-- 
2.25.1