From 8687bf9ef9551bcf93897e33364d121667b1aadf Mon Sep 17 00:00:00 2001

From: Lee Gibson <leegib@gmail.com>

Date: Fri, 26 Feb 2021 14:51:57 +0000

Subject: [PATCH] staging: rtl8192e: Fix possible buffer overflow in _rtl92e_wx_set_scan

Git-commit: 8687bf9ef9551bcf93897e33364d121667b1aadf

Patch-mainline: v5.12-rc3

References: git-fixes

Function _rtl92e_wx_set_scan calls memcpy without checking the length.

A user could control that length and trigger a buffer overflow.

Fix by checking the length is within the maximum allowed size.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

Signed-off-by: Lee Gibson <leegib@gmail.com>

Cc: stable <stable@vger.kernel.org>

Link: https://lore.kernel.org/r/20210226145157.424065-1-leegib@gmail.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/staging/rtl8192e/rtl8192e/rtl_wx.c | 7 ++++---

 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/rtl8192e/rtl8192e/rtl_wx.c b/drivers/staging/rtl8192e/rtl8192e/rtl_wx.c

index 16bcee13f64b..407effde5e71 100644

--- a/drivers/staging/rtl8192e/rtl8192e/rtl_wx.c

+++ b/drivers/staging/rtl8192e/rtl8192e/rtl_wx.c

@@ -406,9 +406,10 @@ static int _rtl92e_wx_set_scan(struct net_device *dev,

 		struct iw_scan_req *req = (struct iw_scan_req *)b;

 		if (req->essid_len) {

-			ieee->current_network.ssid_len = req->essid_len;

-			memcpy(ieee->current_network.ssid, req->essid,

-			       req->essid_len);

+			int len = min_t(int, req->essid_len, IW_ESSID_MAX_SIZE);

+

+			ieee->current_network.ssid_len = len;

+			memcpy(ieee->current_network.ssid, req->essid, len);

 		}

 	}

-- 

2.26.2