staging: rtl8188eu: prevent ->ssid overflow in rtw_wx_set_scan()

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: a2c60d4 ("staging: r8188eu: Add files for new driver - part 16")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/YEHymwsnHewzoam7@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Dan Carpenter

drivers/staging/rtl8188eu/os_dep/ioctl_linux.c

@@ -1133,9 +1133,11 @@ static int rtw_wx_set_scan(struct net_device *dev, struct iw_request_info *a,
 						break;
 					}
 					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].ssid_length = sec_len;
-						memcpy(ssid[ssid_index].ssid, pos, ssid[ssid_index].ssid_length);
+						memcpy(ssid[ssid_index].ssid, pos, sec_len);
 						ssid_index++;
 					}
 					pos += sec_len;