[4/7] Input: gtco: fix endpoint sanity check
diff mbox series

Message ID 20191210113737.4016-5-johan@kernel.org
State Mainlined
Commit a8eeb74df5a6bdb214b2b581b14782c5f5a0cf83
Headers show
Series
  • Input: fix USB alsetting bugs
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Commit Message

Johan Hovold Dec. 10, 2019, 11:37 a.m. UTC
The driver was checking the number of endpoints of the first alternate
setting instead of the current one, something which could lead to the
driver binding to an invalid interface.

This in turn could cause the driver to misbehave or trigger a WARN() in
usb_submit_urb() that kernels with panic_on_warn set would choke on.

Fixes: 162f98dea487 ("Input: gtco - fix crash on detecting device without endpoints")
Cc: stable <stable@vger.kernel.org>     # 4.6
Cc: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/input/tablet/gtco.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

Comments

Vladis Dronov Dec. 11, 2019, 11:59 a.m. UTC | #1
Thanks, Johan! A fix for a bug indeed.

Best regards,
Vladis Dronov | Red Hat, Inc. | The Core Kernel | Senior Software Engineer

----- Original Message -----
> From: "Johan Hovold" <johan@kernel.org>
> To: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
> Cc: linux-input@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Johan Hovold"
> <johan@kernel.org>, "stable" <stable@vger.kernel.org>, "Vladis Dronov" <vdronov@redhat.com>
> Sent: Tuesday, December 10, 2019 12:37:34 PM
> Subject: [PATCH 4/7] Input: gtco: fix endpoint sanity check
> 
> The driver was checking the number of endpoints of the first alternate
> setting instead of the current one, something which could lead to the
> driver binding to an invalid interface.
> 
> This in turn could cause the driver to misbehave or trigger a WARN() in
> usb_submit_urb() that kernels with panic_on_warn set would choke on.
> 
> Fixes: 162f98dea487 ("Input: gtco - fix crash on detecting device without
> endpoints")
> Cc: stable <stable@vger.kernel.org>     # 4.6
> Cc: Vladis Dronov <vdronov@redhat.com>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Patch
diff mbox series

diff --git a/drivers/input/tablet/gtco.c b/drivers/input/tablet/gtco.c
index 35031228a6d0..799c94dda651 100644
--- a/drivers/input/tablet/gtco.c
+++ b/drivers/input/tablet/gtco.c
@@ -875,18 +875,14 @@  static int gtco_probe(struct usb_interface *usbinterface,
 	}
 
 	/* Sanity check that a device has an endpoint */
-	if (usbinterface->altsetting[0].desc.bNumEndpoints < 1) {
+	if (usbinterface->cur_altsetting->desc.bNumEndpoints < 1) {
 		dev_err(&usbinterface->dev,
 			"Invalid number of endpoints\n");
 		error = -EINVAL;
 		goto err_free_urb;
 	}
 
-	/*
-	 * The endpoint is always altsetting 0, we know this since we know
-	 * this device only has one interrupt endpoint
-	 */
-	endpoint = &usbinterface->altsetting[0].endpoint[0].desc;
+	endpoint = &usbinterface->cur_altsetting->endpoint[0].desc;
 
 	/* Some debug */
 	dev_dbg(&usbinterface->dev, "gtco # interfaces: %d\n", usbinterface->num_altsetting);
@@ -973,7 +969,7 @@  static int gtco_probe(struct usb_interface *usbinterface,
 	input_dev->dev.parent = &usbinterface->dev;
 
 	/* Setup the URB, it will be posted later on open of input device */
-	endpoint = &usbinterface->altsetting[0].endpoint[0].desc;
+	endpoint = &usbinterface->cur_altsetting->endpoint[0].desc;
 
 	usb_fill_int_urb(gtco->urbinfo,
 			 udev,