[PATCH 5.10 08/25] Bluetooth: bfusb: fix division by zero in send path

[Greg Kroah-Hartman]

From: Johan Hovold <johan@xxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/bluetooth/bfusb.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/bluetooth/bfusb.c
+++ b/drivers/bluetooth/bfusb.c
@@ -628,6 +628,9 @@ 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;