[PATCH 4.19 02/30] staging: rtl8723bs: prevent ->Ssid overflow in rtw_wx_set_scan()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: "Denis Efremov (Oracle)" <efremov@linux.com>

This code has a check to prevent read overflow but it needs another
check to prevent writing beyond the end of the ->Ssid[] array.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Denis Efremov (Oracle) <efremov@linux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/rtl8723bs/os_dep/ioctl_linux.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
@@ -1359,9 +1359,11 @@ static int rtw_wx_set_scan(struct net_de
 
 					sec_len = *(pos++); len-= 1;
 
-					if (sec_len>0 && sec_len<=len) {
+					if (sec_len > 0 &&
+					    sec_len <= len &&
+					    sec_len <= 32) {
 						ssid[ssid_index].SsidLength = sec_len;
-						memcpy(ssid[ssid_index].Ssid, pos, ssid[ssid_index].SsidLength);
+						memcpy(ssid[ssid_index].Ssid, pos, sec_len);
 						/* DBG_871X("%s COMBO_SCAN with specific ssid:%s, %d\n", __func__ */
 						/* 	, ssid[ssid_index].Ssid, ssid[ssid_index].SsidLength); */
 						ssid_index++;