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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Oliver Neukum <oneukum@suse.com>
Subject: [PATCH 5.2 078/143] usbtmc: more sanity checking for packet size
Date:   Wed,  4 Sep 2019 19:53:41 +0200
Message-Id: <20190904175317.111350107@linuxfoundation.org>
In-Reply-To: <20190904175314.206239922@linuxfoundation.org>
References: <20190904175314.206239922@linuxfoundation.org>
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From: Oliver Neukum <oneukum@suse.com>

commit de7b9aa633b693e77942e12f1769506efae6917b upstream.

A malicious device can make the driver divide ny zero
with a nonsense maximum packet size.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190820092826.17694-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/class/usbtmc.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -2362,8 +2362,11 @@ static int usbtmc_probe(struct usb_inter
 		goto err_put;
 	}
 
+	retcode = -EINVAL;
 	data->bulk_in = bulk_in->bEndpointAddress;
 	data->wMaxPacketSize = usb_endpoint_maxp(bulk_in);
+	if (!data->wMaxPacketSize)
+		goto err_put;
 	dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n", data->bulk_in);
 
 	data->bulk_out = bulk_out->bEndpointAddress;