[PATCH 4.17 141/336] mwifiex: correct histogram data with appropriate index

[Greg Kroah-Hartman]

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

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

From: Xinming Hu <huxm@xxxxxxxxxxx>

[ Upstream commit 30bfce0b63fa68c14ae1613eb9d259fa18644074 ]

Correct snr/nr/rssi data index to avoid possible buffer underflow.

Signed-off-by: Xinming Hu <huxm@xxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/wireless/marvell/mwifiex/util.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/marvell/mwifiex/util.c
+++ b/drivers/net/wireless/marvell/mwifiex/util.c
@@ -708,12 +708,14 @@ void mwifiex_hist_data_set(struct mwifie
 			   s8 nflr)
 {
 	struct mwifiex_histogram_data *phist_data = priv->hist_data;
+	s8 nf   = -nflr;
+	s8 rssi = snr - nflr;
 
 	atomic_inc(&phist_data->num_samples);
 	atomic_inc(&phist_data->rx_rate[rx_rate]);
-	atomic_inc(&phist_data->snr[snr]);
-	atomic_inc(&phist_data->noise_flr[128 + nflr]);
-	atomic_inc(&phist_data->sig_str[nflr - snr]);
+	atomic_inc(&phist_data->snr[snr + 128]);
+	atomic_inc(&phist_data->noise_flr[nf + 128]);
+	atomic_inc(&phist_data->sig_str[rssi + 128]);
 }
 
 /* function to reset histogram data during init/reset */