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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>
Subject: [PATCH 4.9 44/78] staging: rtl8192u: fix ->ssid overflow in r8192_wx_set_scan()
Date:   Mon, 15 Mar 2021 14:52:07 +0100
Message-Id: <20210315135213.513316962@linuxfoundation.org>
In-Reply-To: <20210315135212.060847074@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 87107518d7a93fec6cdb2559588862afeee800fb upstream.

We need to cap len at IW_ESSID_MAX_SIZE (32) to avoid memory corruption.
This can be controlled by the user via the ioctl.

Fixes: 5f53d8ca3d5d ("Staging: add rtl8192SU wireless usb driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/YEHoAWMOSZBUw91F@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/rtl8192u/r8192U_wx.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/staging/rtl8192u/r8192U_wx.c
+++ b/drivers/staging/rtl8192u/r8192U_wx.c
@@ -333,8 +333,10 @@ static int r8192_wx_set_scan(struct net_
 		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);
 		}
 	}