[PATCH] mfd: dln2: more sanity checking for endpoints

[PATCH] mfd: dln2: more sanity checking for endpoints

[Oliver Neukum]

It is not enough to check for the number of endpoints.
The types must also be correct.

Reported-and-tested-by: syzbot+48a2851be24583b864dc@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/mfd/dln2.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index 381593fbe50f..7841c11411d0 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -722,6 +722,8 @@ static int dln2_probe(struct usb_interface *interface,
 		      const struct usb_device_id *usb_id)
 {
 	struct usb_host_interface *hostif = interface->cur_altsetting;
+	struct usb_endpoint_descriptor *epin;
+	struct usb_endpoint_descriptor *epout;
 	struct device *dev = &interface->dev;
 	struct dln2_dev *dln2;
 	int ret;
@@ -731,12 +733,19 @@ static int dln2_probe(struct usb_interface *interface,
 	    hostif->desc.bNumEndpoints < 2)
 		return -ENODEV;
 
+	epin = &hostif->endpoint[0].desc;
+	epout = &hostif->endpoint[1].desc;
+	if (!usb_endpoint_is_bulk_out(epout))
+		return -ENODEV;
+	if (!usb_endpoint_is_bulk_in(epin))
+		return -ENODEV;
+
 	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
 	if (!dln2)
 		return -ENOMEM;
 
-	dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
-	dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+	dln2->ep_out = epout->bEndpointAddress;
+	dln2->ep_in = epin->bEndpointAddress;
 	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 	dln2->interface = interface;
 	usb_set_intfdata(interface, dln2);
-- 
2.16.4

Re: [PATCH] mfd: dln2: more sanity checking for endpoints

[Lee Jones]

On Thu, 21 Nov 2019, Oliver Neukum wrote:

> It is not enough to check for the number of endpoints.
> The types must also be correct.
> 
> Reported-and-tested-by: syzbot+48a2851be24583b864dc@syzkaller.appspotmail.com
> Signed-off-by: Oliver Neukum <oneukum@suse.com>
> ---
>  drivers/mfd/dln2.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)

Applied with Greg's Ack, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog