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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, Johan Hovold <johan@kernel.org>,
        Marcel Holtmann <marcel@holtmann.org>
Subject: [PATCH 4.14 001/186] Bluetooth: bfusb: fix division by zero in send path
Date:   Mon, 24 Jan 2022 19:41:16 +0100
Message-Id: <20220124183937.153147463@linuxfoundation.org>
In-Reply-To: <20220124183937.101330125@linuxfoundation.org>
References: <20220124183937.101330125@linuxfoundation.org>
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From: Johan Hovold <johan@kernel.org>

commit b5e6fa7a12572c82f1e7f2f51fbb02a322291291 upstream.

Add the missing bulk-out endpoint sanity check to probe() to avoid
division by zero in bfusb_send_frame() in case a malicious device has
broken descriptors (or when doing descriptor fuzz testing).

Note that USB core will reject URBs submitted for endpoints with zero
wMaxPacketSize but that drivers doing packet-size calculations still
need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
endpoint descriptors with maxpacket=0")).

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/bluetooth/bfusb.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/bluetooth/bfusb.c
+++ b/drivers/bluetooth/bfusb.c
@@ -644,6 +644,9 @@ static int bfusb_probe(struct usb_interf
 	data->bulk_out_ep   = bulk_out_ep->desc.bEndpointAddress;
 	data->bulk_pkt_size = le16_to_cpu(bulk_out_ep->desc.wMaxPacketSize);
 
+	if (!data->bulk_pkt_size)
+		goto done;
+
 	rwlock_init(&data->lock);
 
 	data->reassembly = NULL;