[PATCH v2 3/4] mfd: dln2: add a limit check for invalid echo

[Octavian Purdila <octavian.purdila@intel.com>]

The echo field in dln2_transfer_complete comes directly from an USB
transfer and we should not trust it is valid.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/mfd/dln2.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index cf22841..df2fda9 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -195,6 +195,9 @@ static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
 	struct dln2_rx_context *rxc;
 	bool valid_slot = false;
 
+	if (rx_slot >= DLN2_MAX_RX_SLOTS)
+		goto out;
+
 	rxc = &rxs->slots[rx_slot];
 
 	/*
@@ -210,6 +213,7 @@ static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
 	}
 	spin_unlock(&rxs->lock);
 
+out:
 	if (!valid_slot)
 		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
 
-- 
1.9.1