From b5e6fa7a12572c82f1e7f2f51fbb02a322291291 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Oct 2021 13:39:44 +0200
Subject: [PATCH] Bluetooth: bfusb: fix division by zero in send path
Git-commit: b5e6fa7a12572c82f1e7f2f51fbb02a322291291
References: git-fixes
Patch-mainline: v5.17-rc1

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: Oliver Neukum <oneukum@suse.com>
---
 drivers/bluetooth/bfusb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/bluetooth/bfusb.c b/drivers/bluetooth/bfusb.c
index 5a321b4076aa..cab93935cc7f 100644
--- a/drivers/bluetooth/bfusb.c
+++ b/drivers/bluetooth/bfusb.c
@@ -628,6 +628,9 @@ static int bfusb_probe(struct usb_interface *intf, const struct usb_device_id *i
 	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;
-- 
2.34.1