From 920c92448839bd4f8eb87a92b08cad56d449caff Mon Sep 17 00:00:00 2001
From: Murray McAllister <murray.mcallister@insomniasec.com>
Date: Mon, 2 Jul 2018 13:07:28 +1200
Subject: [PATCH] staging: rtl8723bs: Prevent an underflow in rtw_check_beacon_data().
Git-commit: 920c92448839bd4f8eb87a92b08cad56d449caff
Patch-mainline: v4.18-rc5
References: bsc#1051510

Dan Carpenter reported an integer underflow issue in the rtl8188eu driver.
This is also needed for the length (signed integer) in rtl8723bs, as it is
later converted to an unsigned integer and used in a memcpy operation.

Original issue is at https://patchwork.kernel.org/patch/9796371/

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Murray McAllister <murray.mcallister@insomniasec.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/rtl8723bs/core/rtw_ap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_ap.c b/drivers/staging/rtl8723bs/core/rtw_ap.c
index 45c05527a57a..faf4b4158cfa 100644
--- a/drivers/staging/rtl8723bs/core/rtw_ap.c
+++ b/drivers/staging/rtl8723bs/core/rtw_ap.c
@@ -1051,7 +1051,7 @@ int rtw_check_beacon_data(struct adapter *padapter, u8 *pbuf,  int len)
 		return _FAIL;
 
 
-	if (len > MAX_IE_SZ)
+	if (len < 0 || len > MAX_IE_SZ)
 		return _FAIL;
 
 	pbss_network->IELength = len;
-- 
2.18.0