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* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-01 12:42 Andrej Shadura
  2019-04-10 12:02 ` Jiri Kosina
  2019-10-03  7:19 ` Andrej Shadura
  0 siblings, 2 replies; 15+ messages in thread
From: Andrej Shadura @ 2019-04-01 12:42 UTC (permalink / raw)
  To: Jiří Kosina
  Cc: linux-input, linux-usb, Andrzej Pietrasiewicz, kernel,
	Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

U2F Zero supports custom commands for blinking the LED and getting data
from the internal hardware RNG. Expose the blinking function as a LED
device, and the internal hardware RNG as an HWRNG so that it can be used
to feed the enthropy pool.

Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>
---
 drivers/hid/Kconfig       |  15 ++
 drivers/hid/Makefile      |   1 +
 drivers/hid/hid-ids.h     |   1 +
 drivers/hid/hid-u2fzero.c | 371 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 388 insertions(+)
 create mode 100644 drivers/hid/hid-u2fzero.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 41e9935fc584..6efb5a43ffc8 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -989,6 +989,21 @@ config HID_UDRAW_PS3
 	  Say Y here if you want to use the THQ uDraw gaming tablet for
 	  the PS3.
 
+config HID_U2FZERO
+	tristate "U2F Zero LED and RNG support"
+	depends on USB_HID
+	depends on LEDS_CLASS
+	help
+	  Support for the LED of the U2F Zero device.
+
+	  U2F Zero supports custom commands for blinking the LED
+	  and getting data from the internal hardware RNG.
+	  The internal hardware can be used to feed the enthropy pool.
+
+	  U2F Zero only supports blinking its LED, so this driver doesn't
+	  allow setting the brightness to anything but 1, which will
+	  trigger a single blink and immediately reset to back 0.
+
 config HID_WACOM
 	tristate "Wacom Intuos/Graphire tablet support (USB)"
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 896a51ce7ce0..d9724ab8df5f 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -108,6 +108,7 @@ obj-$(CONFIG_HID_THRUSTMASTER)	+= hid-tmff.o
 obj-$(CONFIG_HID_TIVO)		+= hid-tivo.o
 obj-$(CONFIG_HID_TOPSEED)	+= hid-topseed.o
 obj-$(CONFIG_HID_TWINHAN)	+= hid-twinhan.o
+obj-$(CONFIG_HID_U2FZERO)	+= hid-u2fzero.o
 obj-$(CONFIG_HID_UCLOGIC)	+= hid-uclogic.o
 obj-$(CONFIG_HID_UDRAW_PS3)	+= hid-udraw-ps3.o
 obj-$(CONFIG_HID_LED)		+= hid-led.o
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 24f846d67478..36f898eab36f 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -321,6 +321,7 @@
 #define USB_DEVICE_ID_CYGNAL_RADIO_SI470X	0x818a
 #define USB_DEVICE_ID_FOCALTECH_FTXXXX_MULTITOUCH	0x81b9
 #define USB_DEVICE_ID_CYGNAL_CP2112	0xea90
+#define USB_DEVICE_ID_U2F_ZERO		0x8acf
 
 #define USB_DEVICE_ID_CYGNAL_RADIO_SI4713       0x8244
 
diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
new file mode 100644
index 000000000000..d11a5cb56a0d
--- /dev/null
+++ b/drivers/hid/hid-u2fzero.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * U2F Zero LED and RNG driver
+ *
+ * Copyright 2018 Andrej Shadura <andrew@shadura.me>
+ * Loosely based on drivers/hid/hid-led.c
+ *              and drivers/usb/misc/chaoskey.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2.
+ */
+
+#include <linux/hid.h>
+#include <linux/hidraw.h>
+#include <linux/hw_random.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/usb.h>
+
+#include "usbhid/usbhid.h"
+#include "hid-ids.h"
+
+#define DRIVER_SHORT		"u2fzero"
+
+#define HID_REPORT_SIZE		64
+
+/* We only use broadcast (CID-less) messages */
+#define CID_BROADCAST		0xffffffff
+
+struct u2f_hid_msg {
+	u32 cid;
+	union {
+		struct {
+			u8 cmd;
+			u8 bcnth;
+			u8 bcntl;
+			u8 data[HID_REPORT_SIZE - 7];
+		} init;
+		struct {
+			u8 seq;
+			u8 data[HID_REPORT_SIZE - 5];
+		} cont;
+	};
+} __packed;
+
+struct u2f_hid_report {
+	u8 report_type;
+	struct u2f_hid_msg msg;
+} __packed;
+
+#define U2F_HID_MSG_LEN(f)	(size_t)(((f).init.bcnth << 8) + (f).init.bcntl)
+
+/* Custom extensions to the U2FHID protocol */
+#define U2F_CUSTOM_GET_RNG	0x21
+#define U2F_CUSTOM_WINK		0x24
+
+struct u2fzero_device {
+	struct hid_device	*hdev;
+	struct urb		*urb;	    /* URB for the RNG data */
+	struct led_classdev	ldev;	    /* Embedded struct for led */
+	struct hwrng		hwrng;	    /* Embedded struct for hwrng */
+	char			*led_name;
+	char			*rng_name;
+	u8			*buf_out;
+	u8			*buf_in;
+	struct mutex		lock;
+	bool			present;
+};
+
+static int u2fzero_send(struct u2fzero_device *dev, struct u2f_hid_report *req)
+{
+	int ret;
+
+	mutex_lock(&dev->lock);
+
+	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
+
+	ret = hid_hw_output_report(dev->hdev, dev->buf_out,
+				   sizeof(struct u2f_hid_msg));
+
+	mutex_unlock(&dev->lock);
+
+	if (ret < 0)
+		return ret;
+
+	return ret == sizeof(struct u2f_hid_msg) ? 0 : -EMSGSIZE;
+}
+
+struct u2fzero_transfer_context {
+	struct completion done;
+	int status;
+};
+
+static void u2fzero_read_callback(struct urb *urb)
+{
+	struct u2fzero_transfer_context *ctx = urb->context;
+
+	ctx->status = urb->status;
+	complete(&ctx->done);
+}
+
+static int u2fzero_recv(struct u2fzero_device *dev,
+			struct u2f_hid_report *req,
+			struct u2f_hid_msg *resp)
+{
+	int ret;
+	struct hid_device *hdev = dev->hdev;
+	struct u2fzero_transfer_context ctx;
+
+	mutex_lock(&dev->lock);
+
+	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
+
+	dev->urb->context = &ctx;
+	init_completion(&ctx.done);
+
+	ret = usb_submit_urb(dev->urb, GFP_NOIO);
+	if (unlikely(ret)) {
+		hid_err(hdev, "usb_submit_urb failed: %d", ret);
+		goto err;
+	}
+
+	ret = hid_hw_output_report(dev->hdev, dev->buf_out,
+				   sizeof(struct u2f_hid_msg));
+
+	if (ret < 0) {
+		hid_err(hdev, "hid_hw_output_report failed: %d", ret);
+		goto err;
+	}
+
+	ret = (wait_for_completion_timeout(
+		&ctx.done, msecs_to_jiffies(USB_CTRL_SET_TIMEOUT)));
+	if (ret < 0) {
+		usb_kill_urb(dev->urb);
+		hid_err(hdev, "urb submission timed out");
+	} else {
+		ret = dev->urb->actual_length;
+		memcpy(resp, dev->buf_in, ret);
+	}
+
+err:
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+static int u2fzero_blink(struct led_classdev *ldev)
+{
+	struct u2fzero_device *dev = container_of(ldev,
+		struct u2fzero_device, ldev);
+	struct u2f_hid_report req = {
+		.report_type = 0,
+		.msg.cid = CID_BROADCAST,
+		.msg.init = {
+			.cmd = U2F_CUSTOM_WINK,
+			.bcnth = 0,
+			.bcntl = 0,
+			.data  = {0},
+		}
+	};
+	return u2fzero_send(dev, &req);
+}
+
+static int u2fzero_brightness_set(struct led_classdev *ldev,
+				  enum led_brightness brightness)
+{
+	ldev->brightness = LED_OFF;
+	if (brightness)
+		return u2fzero_blink(ldev);
+	else
+		return 0;
+}
+
+static int u2fzero_rng_read(struct hwrng *rng, void *data,
+			    size_t max, bool wait)
+{
+	struct u2fzero_device *dev = container_of(rng,
+		struct u2fzero_device, hwrng);
+	struct u2f_hid_report req = {
+		.report_type = 0,
+		.msg.cid = CID_BROADCAST,
+		.msg.init = {
+			.cmd = U2F_CUSTOM_GET_RNG,
+			.bcnth = 0,
+			.bcntl = 0,
+			.data  = {0},
+		}
+	};
+	struct u2f_hid_msg resp;
+	int ret;
+	size_t actual_length;
+
+	if (!dev->present) {
+		hid_dbg(dev->hdev, "device not present");
+		return 0;
+	}
+
+	ret = u2fzero_recv(dev, &req, &resp);
+	if (ret < 0)
+		return 0;
+
+	/* only take the minimum amount of data it is safe to take */
+	actual_length = min3((size_t)ret - offsetof(struct u2f_hid_msg,
+		init.data), U2F_HID_MSG_LEN(resp), max);
+
+	memcpy(data, resp.init.data, actual_length);
+
+	return actual_length;
+}
+
+static int u2fzero_init_led(struct u2fzero_device *dev,
+			    unsigned int minor)
+{
+	dev->led_name = devm_kasprintf(&dev->hdev->dev, GFP_KERNEL,
+		"%s%u", DRIVER_SHORT, minor);
+	if (dev->led_name == NULL)
+		return -ENOMEM;
+
+	dev->ldev.name = dev->led_name;
+	dev->ldev.max_brightness = LED_ON;
+	dev->ldev.flags = LED_HW_PLUGGABLE;
+	dev->ldev.brightness_set_blocking = u2fzero_brightness_set;
+
+	return devm_led_classdev_register(&dev->hdev->dev, &dev->ldev);
+}
+
+static int u2fzero_init_hwrng(struct u2fzero_device *dev,
+			      unsigned int minor)
+{
+	dev->rng_name = devm_kasprintf(&dev->hdev->dev, GFP_KERNEL,
+		"%s-rng%u", DRIVER_SHORT, minor);
+	if (dev->rng_name == NULL)
+		return -ENOMEM;
+
+	dev->hwrng.name = dev->rng_name;
+	dev->hwrng.read = u2fzero_rng_read;
+	dev->hwrng.quality = 1;
+
+	return devm_hwrng_register(&dev->hdev->dev, &dev->hwrng);
+}
+
+static int u2fzero_fill_in_urb(struct u2fzero_device *dev)
+{
+	struct hid_device *hdev = dev->hdev;
+	struct usb_device *udev;
+	struct usbhid_device *usbhid = hdev->driver_data;
+	unsigned int pipe_in;
+	struct usb_host_endpoint *ep;
+
+	if (dev->hdev->bus != BUS_USB)
+		return -EINVAL;
+
+	udev = hid_to_usb_dev(hdev);
+
+	if (!usbhid->urbout || !usbhid->urbin)
+		return -ENODEV;
+
+	ep = usb_pipe_endpoint(udev, usbhid->urbin->pipe);
+	if (!ep)
+		return -ENODEV;
+
+	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->urb)
+		return -ENOMEM;
+
+	pipe_in = (usbhid->urbin->pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
+
+	usb_fill_int_urb(dev->urb,
+		udev,
+		pipe_in,
+		dev->buf_in,
+		HID_REPORT_SIZE,
+		u2fzero_read_callback,
+		NULL,
+		ep->desc.bInterval);
+
+	return 0;
+}
+
+static int u2fzero_probe(struct hid_device *hdev,
+			 const struct hid_device_id *id)
+{
+	struct u2fzero_device *dev;
+	unsigned int minor;
+	int ret;
+
+	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (dev == NULL)
+		return -ENOMEM;
+
+	dev->buf_out = devm_kmalloc(&hdev->dev,
+		sizeof(struct u2f_hid_report), GFP_KERNEL);
+	if (dev->buf_out == NULL)
+		return -ENOMEM;
+
+	dev->buf_in = devm_kmalloc(&hdev->dev,
+		sizeof(struct u2f_hid_msg), GFP_KERNEL);
+	if (dev->buf_in == NULL)
+		return -ENOMEM;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	dev->hdev = hdev;
+	hid_set_drvdata(hdev, dev);
+	mutex_init(&dev->lock);
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		return ret;
+
+	u2fzero_fill_in_urb(dev);
+
+	dev->present = true;
+
+	minor = ((struct hidraw *) hdev->hidraw)->minor;
+
+	ret = u2fzero_init_led(dev, minor);
+	if (ret) {
+		hid_hw_stop(hdev);
+		return ret;
+	}
+
+	hid_info(hdev, "U2F Zero LED initialised\n");
+
+	ret = u2fzero_init_hwrng(dev, minor);
+	if (ret) {
+		hid_hw_stop(hdev);
+		return ret;
+	}
+
+	hid_info(hdev, "U2F Zero RNG initialised\n");
+
+	return 0;
+}
+
+static void u2fzero_remove(struct hid_device *hdev)
+{
+	struct u2fzero_device *dev = hid_get_drvdata(hdev);
+
+	mutex_lock(&dev->lock);
+	dev->present = false;
+	mutex_unlock(&dev->lock);
+
+	hid_hw_stop(hdev);
+	usb_poison_urb(dev->urb);
+	usb_free_urb(dev->urb);
+}
+
+static const struct hid_device_id u2fzero_table[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL,
+	  USB_DEVICE_ID_U2F_ZERO) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, u2fzero_table);
+
+static struct hid_driver u2fzero_driver = {
+	.name = "hid-" DRIVER_SHORT,
+	.probe = u2fzero_probe,
+	.remove = u2fzero_remove,
+	.id_table = u2fzero_table,
+};
+
+module_hid_driver(u2fzero_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrej Shadura <andrew@shadura.me>");
+MODULE_DESCRIPTION("U2F Zero LED and RNG driver");

^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-10 12:02 ` Jiri Kosina
  2019-04-10 12:02   ` [PATCH v3] " Jiri Kosina
  2019-04-11  9:58   ` [v3] " Benjamin Tissoires
  0 siblings, 2 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-10 12:02 UTC (permalink / raw)
  To: Andrej Shadura
  Cc: linux-input, linux-usb, Andrzej Pietrasiewicz, kernel,
	Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Mon, 1 Apr 2019, Andrej Shadura wrote:

> U2F Zero supports custom commands for blinking the LED and getting data
> from the internal hardware RNG. Expose the blinking function as a LED
> device, and the internal hardware RNG as an HWRNG so that it can be used
> to feed the enthropy pool.

So I still am not really happy about this being wired up into generic HID 
although it's really a USB driver, but we've discussed that already, and I 
don't see any option that'd work substantially better in this case, 
especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero, 
thanks!

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-10 12:02 ` Jiri Kosina
@ 2019-04-10 12:02   ` " Jiri Kosina
  2019-04-11  9:58   ` [v3] " Benjamin Tissoires
  1 sibling, 0 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-10 12:02 UTC (permalink / raw)
  To: Andrej Shadura
  Cc: linux-input, linux-usb, Andrzej Pietrasiewicz, kernel,
	Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Mon, 1 Apr 2019, Andrej Shadura wrote:

> U2F Zero supports custom commands for blinking the LED and getting data
> from the internal hardware RNG. Expose the blinking function as a LED
> device, and the internal hardware RNG as an HWRNG so that it can be used
> to feed the enthropy pool.

So I still am not really happy about this being wired up into generic HID 
although it's really a USB driver, but we've discussed that already, and I 
don't see any option that'd work substantially better in this case, 
especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero, 
thanks!

-- 
Jiri Kosina
SUSE Labs


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-11  9:58   ` " Benjamin Tissoires
  2019-04-11  9:58     ` [PATCH v3] " Benjamin Tissoires
  2019-04-11 10:35     ` [v3] " Jiri Kosina
  0 siblings, 2 replies; 15+ messages in thread
From: Benjamin Tissoires @ 2019-04-11  9:58 UTC (permalink / raw)
  To: Jiri Kosina
  Cc: Andrej Shadura, linux-input, linux-usb, Andrzej Pietrasiewicz,
	kernel, Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Wed, Apr 10, 2019 at 3:14 PM Jiri Kosina <jikos@kernel.org> wrote:
>
> On Mon, 1 Apr 2019, Andrej Shadura wrote:
>
> > U2F Zero supports custom commands for blinking the LED and getting data
> > from the internal hardware RNG. Expose the blinking function as a LED
> > device, and the internal hardware RNG as an HWRNG so that it can be used
> > to feed the enthropy pool.
>
> So I still am not really happy about this being wired up into generic HID
> although it's really a USB driver, but we've discussed that already, and I
> don't see any option that'd work substantially better in this case,
> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> thanks!
>

Hi wish I were CC-ed on these threads.

My CI script now fails because hid-u2fzero.ko needs
devm_hwrng_register and the Kconfig doesn't force pulling the right
dependency.

Also, you probably want to add in .probe() a check for the actual
transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or
you can not use the usbhid functions without crashing the kernel.

Cheers,
Benjamin

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-11  9:58   ` [v3] " Benjamin Tissoires
@ 2019-04-11  9:58     ` " Benjamin Tissoires
  2019-04-11 10:35     ` [v3] " Jiri Kosina
  1 sibling, 0 replies; 15+ messages in thread
From: Benjamin Tissoires @ 2019-04-11  9:58 UTC (permalink / raw)
  To: Jiri Kosina
  Cc: Andrej Shadura, linux-input, linux-usb, Andrzej Pietrasiewicz,
	kernel, Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Wed, Apr 10, 2019 at 3:14 PM Jiri Kosina <jikos@kernel.org> wrote:
>
> On Mon, 1 Apr 2019, Andrej Shadura wrote:
>
> > U2F Zero supports custom commands for blinking the LED and getting data
> > from the internal hardware RNG. Expose the blinking function as a LED
> > device, and the internal hardware RNG as an HWRNG so that it can be used
> > to feed the enthropy pool.
>
> So I still am not really happy about this being wired up into generic HID
> although it's really a USB driver, but we've discussed that already, and I
> don't see any option that'd work substantially better in this case,
> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> thanks!
>

Hi wish I were CC-ed on these threads.

My CI script now fails because hid-u2fzero.ko needs
devm_hwrng_register and the Kconfig doesn't force pulling the right
dependency.

Also, you probably want to add in .probe() a check for the actual
transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or
you can not use the usbhid functions without crashing the kernel.

Cheers,
Benjamin

^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-11 10:35     ` " Jiri Kosina
  2019-04-11 10:35       ` [PATCH v3] " Jiri Kosina
  2019-04-11 11:52       ` [v3] " Andrej Shadura
  0 siblings, 2 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-11 10:35 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Andrej Shadura, linux-input, linux-usb, Andrzej Pietrasiewicz,
	kernel, Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Thu, 11 Apr 2019, Benjamin Tissoires wrote:

> > So I still am not really happy about this being wired up into generic HID
> > although it's really a USB driver, but we've discussed that already, and I
> > don't see any option that'd work substantially better in this case,
> > especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> > thanks!
> >
> 
> Hi wish I were CC-ed on these threads.

Gah, for some reason I was convinced you were.

> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
> and the Kconfig doesn't force pulling the right dependency.
> 
> Also, you probably want to add in .probe() a check for the actual 
> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
> you can not use the usbhid functions without crashing the kernel.

Benjamin, I love your CI :)

Andrej, could you please send fixups on top of the applied patch?

Thanks,

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-11 10:35     ` [v3] " Jiri Kosina
@ 2019-04-11 10:35       ` " Jiri Kosina
  2019-04-11 11:52       ` [v3] " Andrej Shadura
  1 sibling, 0 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-11 10:35 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Andrej Shadura, linux-input, linux-usb, Andrzej Pietrasiewicz,
	kernel, Theodore Ts'o, Vasily Khoruzhick, Nick Kossifidis,
	linux-crypto

On Thu, 11 Apr 2019, Benjamin Tissoires wrote:

> > So I still am not really happy about this being wired up into generic HID
> > although it's really a USB driver, but we've discussed that already, and I
> > don't see any option that'd work substantially better in this case,
> > especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> > thanks!
> >
> 
> Hi wish I were CC-ed on these threads.

Gah, for some reason I was convinced you were.

> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
> and the Kconfig doesn't force pulling the right dependency.
> 
> Also, you probably want to add in .probe() a check for the actual 
> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
> you can not use the usbhid functions without crashing the kernel.

Benjamin, I love your CI :)

Andrej, could you please send fixups on top of the applied patch?

Thanks,

-- 
Jiri Kosina
SUSE Labs


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-11 11:52       ` " Andrej Shadura
  2019-04-11 11:52         ` [PATCH v3] " Andrej Shadura
  2019-04-17 14:43         ` [v3] " Jiri Kosina
  0 siblings, 2 replies; 15+ messages in thread
From: Andrej Shadura @ 2019-04-11 11:52 UTC (permalink / raw)
  To: Jiri Kosina, Benjamin Tissoires
  Cc: linux-input, linux-usb, Andrzej Pietrasiewicz, kernel, linux-crypto

On 11/04/2019 12:35, Jiri Kosina wrote:
> On Thu, 11 Apr 2019, Benjamin Tissoires wrote:
> 
>>> So I still am not really happy about this being wired up into generic HID
>>> although it's really a USB driver, but we've discussed that already, and I
>>> don't see any option that'd work substantially better in this case,
>>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
>>> thanks!
>>>
>>
>> Hi wish I were CC-ed on these threads.
> 
> Gah, for some reason I was convinced you were.
> 
>> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
>> and the Kconfig doesn't force pulling the right dependency.

>> Also, you probably want to add in .probe() a check for the actual 
>> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
>> you can not use the usbhid functions without crashing the kernel.

Thanks, that’s very useful.

> Benjamin, I love your CI :)
> 
> Andrej, could you please send fixups on top of the applied patch?

Sure, will do.

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-11 11:52       ` [v3] " Andrej Shadura
@ 2019-04-11 11:52         ` " Andrej Shadura
  2019-04-17 14:43         ` [v3] " Jiri Kosina
  1 sibling, 0 replies; 15+ messages in thread
From: Andrej Shadura @ 2019-04-11 11:52 UTC (permalink / raw)
  To: Jiri Kosina, Benjamin Tissoires
  Cc: linux-input, linux-usb, Andrzej Pietrasiewicz, kernel, linux-crypto

On 11/04/2019 12:35, Jiri Kosina wrote:
> On Thu, 11 Apr 2019, Benjamin Tissoires wrote:
> 
>>> So I still am not really happy about this being wired up into generic HID
>>> although it's really a USB driver, but we've discussed that already, and I
>>> don't see any option that'd work substantially better in this case,
>>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
>>> thanks!
>>>
>>
>> Hi wish I were CC-ed on these threads.
> 
> Gah, for some reason I was convinced you were.
> 
>> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
>> and the Kconfig doesn't force pulling the right dependency.

>> Also, you probably want to add in .probe() a check for the actual 
>> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
>> you can not use the usbhid functions without crashing the kernel.

Thanks, that’s very useful.

> Benjamin, I love your CI :)
> 
> Andrej, could you please send fixups on top of the applied patch?

Sure, will do.

-- 
Cheers,
  Andrej

^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-17 14:43         ` " Jiri Kosina
  2019-04-17 14:43           ` [PATCH v3] " Jiri Kosina
  2019-04-17 14:47           ` [v3] " Andrej Shadura
  0 siblings, 2 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-17 14:43 UTC (permalink / raw)
  To: Andrej Shadura
  Cc: Benjamin Tissoires, linux-input, linux-usb,
	Andrzej Pietrasiewicz, kernel, linux-crypto

On Thu, 11 Apr 2019, Andrej Shadura wrote:

> >>> So I still am not really happy about this being wired up into generic HID
> >>> although it's really a USB driver, but we've discussed that already, and I
> >>> don't see any option that'd work substantially better in this case,
> >>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> >>> thanks!
> >>>
> >>
> >> Hi wish I were CC-ed on these threads.
> > 
> > Gah, for some reason I was convinced you were.
> > 
> >> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
> >> and the Kconfig doesn't force pulling the right dependency.
> 
> >> Also, you probably want to add in .probe() a check for the actual 
> >> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
> >> you can not use the usbhid functions without crashing the kernel.
> 
> Thanks, that’s very useful.
> 
> > Benjamin, I love your CI :)
> > 
> > Andrej, could you please send fixups on top of the applied patch?
> 
> Sure, will do.

I didn't receive any followup; the Kconfig dependency has already been 
fixed by Mao Wenan, and I've just queued the patch below on top of that as 
well.




From: Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH] HID: u2fzero: fail probe if not using USB transport

u2fzero driver is USB-only. Therefore we have to give up in ->probe()
callback in case we're called with non-USB transport driver bound,
otherwise the kernel will crash trying to use USBHID API on a non-USB
transport.

Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
Reported-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/hid/hid-u2fzero.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
index d11a5cb56a0d..95e0807878c7 100644
--- a/drivers/hid/hid-u2fzero.c
+++ b/drivers/hid/hid-u2fzero.c
@@ -286,6 +286,9 @@ static int u2fzero_probe(struct hid_device *hdev,
 	unsigned int minor;
 	int ret;
 
+	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
+		return -EINVAL;
+
 	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
 	if (dev == NULL)
 		return -ENOMEM;

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-17 14:43         ` [v3] " Jiri Kosina
@ 2019-04-17 14:43           ` " Jiri Kosina
  2019-04-17 14:47           ` [v3] " Andrej Shadura
  1 sibling, 0 replies; 15+ messages in thread
From: Jiri Kosina @ 2019-04-17 14:43 UTC (permalink / raw)
  To: Andrej Shadura
  Cc: Benjamin Tissoires, linux-input, linux-usb,
	Andrzej Pietrasiewicz, kernel, linux-crypto

On Thu, 11 Apr 2019, Andrej Shadura wrote:

> >>> So I still am not really happy about this being wired up into generic HID
> >>> although it's really a USB driver, but we've discussed that already, and I
> >>> don't see any option that'd work substantially better in this case,
> >>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
> >>> thanks!
> >>>
> >>
> >> Hi wish I were CC-ed on these threads.
> > 
> > Gah, for some reason I was convinced you were.
> > 
> >> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
> >> and the Kconfig doesn't force pulling the right dependency.
> 
> >> Also, you probably want to add in .probe() a check for the actual 
> >> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
> >> you can not use the usbhid functions without crashing the kernel.
> 
> Thanks, that’s very useful.
> 
> > Benjamin, I love your CI :)
> > 
> > Andrej, could you please send fixups on top of the applied patch?
> 
> Sure, will do.

I didn't receive any followup; the Kconfig dependency has already been 
fixed by Mao Wenan, and I've just queued the patch below on top of that as 
well.




From: Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH] HID: u2fzero: fail probe if not using USB transport

u2fzero driver is USB-only. Therefore we have to give up in ->probe()
callback in case we're called with non-USB transport driver bound,
otherwise the kernel will crash trying to use USBHID API on a non-USB
transport.

Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
Reported-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/hid/hid-u2fzero.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
index d11a5cb56a0d..95e0807878c7 100644
--- a/drivers/hid/hid-u2fzero.c
+++ b/drivers/hid/hid-u2fzero.c
@@ -286,6 +286,9 @@ static int u2fzero_probe(struct hid_device *hdev,
 	unsigned int minor;
 	int ret;
 
+	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
+		return -EINVAL;
+
 	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
 	if (dev == NULL)
 		return -ENOMEM;

-- 
Jiri Kosina
SUSE Labs


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [v3] HID: add driver for U2F Zero built-in LED and RNG
@ 2019-04-17 14:47           ` " Andrej Shadura
  2019-04-17 14:47             ` [PATCH v3] " Andrej Shadura
  0 siblings, 1 reply; 15+ messages in thread
From: Andrej Shadura @ 2019-04-17 14:47 UTC (permalink / raw)
  To: Jiri Kosina
  Cc: Benjamin Tissoires, linux-input, linux-usb,
	Andrzej Pietrasiewicz, kernel, linux-crypto

On 17/04/2019 16:43, Jiri Kosina wrote:
> On Thu, 11 Apr 2019, Andrej Shadura wrote:
> 
>>>>> So I still am not really happy about this being wired up into generic HID
>>>>> although it's really a USB driver, but we've discussed that already, and I
>>>>> don't see any option that'd work substantially better in this case,
>>>>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
>>>>> thanks!
>>>>>
>>>>
>>>> Hi wish I were CC-ed on these threads.
>>>
>>> Gah, for some reason I was convinced you were.
>>>
>>>> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
>>>> and the Kconfig doesn't force pulling the right dependency.
>>
>>>> Also, you probably want to add in .probe() a check for the actual 
>>>> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
>>>> you can not use the usbhid functions without crashing the kernel.
>>
>> Thanks, that’s very useful.
>>
>>> Benjamin, I love your CI :)
>>>
>>> Andrej, could you please send fixups on top of the applied patch?
>>
>> Sure, will do.
> 
> I didn't receive any followup; the Kconfig dependency has already been 
> fixed by Mao Wenan, and I've just queued the patch below on top of that as 
> well.

Sorry, I’ve had too much on my plate in the recent days, so I’ve
unfortunately been pushing this task off a bit. Thanks to both of you,
Mao and Jiří, both things should have really been done by me. I’ll try
to get those things right from the beginning the next time.

> From: Jiri Kosina <jkosina@suse.cz>
> Subject: [PATCH] HID: u2fzero: fail probe if not using USB transport
> 
> u2fzero driver is USB-only. Therefore we have to give up in ->probe()
> callback in case we're called with non-USB transport driver bound,
> otherwise the kernel will crash trying to use USBHID API on a non-USB
> transport.
> 
> Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
> Reported-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
>  drivers/hid/hid-u2fzero.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
> index d11a5cb56a0d..95e0807878c7 100644
> --- a/drivers/hid/hid-u2fzero.c
> +++ b/drivers/hid/hid-u2fzero.c
> @@ -286,6 +286,9 @@ static int u2fzero_probe(struct hid_device *hdev,
>  	unsigned int minor;
>  	int ret;
>  
> +	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
> +		return -EINVAL;
> +
>  	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
>  	if (dev == NULL)
>  		return -ENOMEM;
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-17 14:47           ` [v3] " Andrej Shadura
@ 2019-04-17 14:47             ` " Andrej Shadura
  0 siblings, 0 replies; 15+ messages in thread
From: Andrej Shadura @ 2019-04-17 14:47 UTC (permalink / raw)
  To: Jiri Kosina
  Cc: Benjamin Tissoires, linux-input, linux-usb,
	Andrzej Pietrasiewicz, kernel, linux-crypto

On 17/04/2019 16:43, Jiri Kosina wrote:
> On Thu, 11 Apr 2019, Andrej Shadura wrote:
> 
>>>>> So I still am not really happy about this being wired up into generic HID
>>>>> although it's really a USB driver, but we've discussed that already, and I
>>>>> don't see any option that'd work substantially better in this case,
>>>>> especially from the UX point of view. Oh well. Applied to for-5.2/u2fzero,
>>>>> thanks!
>>>>>
>>>>
>>>> Hi wish I were CC-ed on these threads.
>>>
>>> Gah, for some reason I was convinced you were.
>>>
>>>> My CI script now fails because hid-u2fzero.ko needs devm_hwrng_register 
>>>> and the Kconfig doesn't force pulling the right dependency.
>>
>>>> Also, you probably want to add in .probe() a check for the actual 
>>>> transport driver (`hid_is_using_ll_driver(hdev, &usb_hid_driver)`) or 
>>>> you can not use the usbhid functions without crashing the kernel.
>>
>> Thanks, that’s very useful.
>>
>>> Benjamin, I love your CI :)
>>>
>>> Andrej, could you please send fixups on top of the applied patch?
>>
>> Sure, will do.
> 
> I didn't receive any followup; the Kconfig dependency has already been 
> fixed by Mao Wenan, and I've just queued the patch below on top of that as 
> well.

Sorry, I’ve had too much on my plate in the recent days, so I’ve
unfortunately been pushing this task off a bit. Thanks to both of you,
Mao and Jiří, both things should have really been done by me. I’ll try
to get those things right from the beginning the next time.

> From: Jiri Kosina <jkosina@suse.cz>
> Subject: [PATCH] HID: u2fzero: fail probe if not using USB transport
> 
> u2fzero driver is USB-only. Therefore we have to give up in ->probe()
> callback in case we're called with non-USB transport driver bound,
> otherwise the kernel will crash trying to use USBHID API on a non-USB
> transport.
> 
> Fixes: 42337b9d4d958("HID: add driver for U2F Zero built-in LED and RNG")
> Reported-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
>  drivers/hid/hid-u2fzero.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
> index d11a5cb56a0d..95e0807878c7 100644
> --- a/drivers/hid/hid-u2fzero.c
> +++ b/drivers/hid/hid-u2fzero.c
> @@ -286,6 +286,9 @@ static int u2fzero_probe(struct hid_device *hdev,
>  	unsigned int minor;
>  	int ret;
>  
> +	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
> +		return -EINVAL;
> +
>  	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
>  	if (dev == NULL)
>  		return -ENOMEM;
> 


-- 
Cheers,
  Andrej

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-04-01 12:42 [v3] HID: add driver for U2F Zero built-in LED and RNG Andrej Shadura
  2019-04-10 12:02 ` Jiri Kosina
@ 2019-10-03  7:19 ` Andrej Shadura
  2019-10-03 15:25   ` Alan Stern
  1 sibling, 1 reply; 15+ messages in thread
From: Andrej Shadura @ 2019-10-03  7:19 UTC (permalink / raw)
  To: linux-usb
  Cc: Jiří Kosina, linux-input, Andrzej Pietrasiewicz,
	kernel, Ezequiel Garcia, Vasily Khoruzhick

On 01/04/2019 14:42, Andrej Shadura wrote:
> U2F Zero supports custom commands for blinking the LED and getting data
> from the internal hardware RNG. Expose the blinking function as a LED
> device, and the internal hardware RNG as an HWRNG so that it can be used
> to feed the enthropy pool.
> 
> Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>

I’ve been testing this with a different modification of U2F Zero,
Nitrokey FIDO U2F, and on that device only I’m getting a kernel warning
(see below).

> +static int u2fzero_recv(struct u2fzero_device *dev,
> +			struct u2f_hid_report *req,
> +			struct u2f_hid_msg *resp)
> +{
> +	int ret;
> +	struct hid_device *hdev = dev->hdev;
> +	struct u2fzero_transfer_context ctx;
> +
> +	mutex_lock(&dev->lock);
> +
> +	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
> +
> +	dev->urb->context = &ctx;
> +	init_completion(&ctx.done);
> +
> +	ret = usb_submit_urb(dev->urb, GFP_NOIO);

Here, usb_submit_urb() returns EBUSY in the first attempt to read random
numbers from the device:

URB ffff917256d5d540 submitted while active
WARNING: CPU: 3 PID: 31 at drivers/usb/core/urb.c:363
usb_submit_urb+0x4c2/0x5b0
<...>
Call Trace:
 u2fzero_rng_read+0x16e/0x340 [hid_u2fzero]
 ? ttwu_do_activate+0x67/0x90
 add_early_randomness+0x53/0xc0
 hwrng_register+0x175/0x180
 devm_hwrng_register+0x41/0x7e
 u2fzero_probe+0x2dd/0x350 [hid_u2fzero]
 hid_device_probe+0x119/0x180 [hid]
 really_probe+0xfe/0x3b0
 driver_probe_device+0xba/0x100
 __device_attach_driver+0x97/0x100

I don’t understand why since 1) it’s likely to be the first transmission
of this URB, 2) there’s a mutex locked just before it. I received a
comment from a colleague mentioning I’m probably not using the mutex
correctly, but I don’t understand why.

I’m trying to figure this out, so I’d welcome any help with it.

Thanks in advance.

> +	if (unlikely(ret)) {
> +		hid_err(hdev, "usb_submit_urb failed: %d", ret);
> +		goto err;
> +	}
> +
> +	ret = hid_hw_output_report(dev->hdev, dev->buf_out,
> +				   sizeof(struct u2f_hid_msg));
> +
> +	if (ret < 0) {
> +		hid_err(hdev, "hid_hw_output_report failed: %d", ret);
> +		goto err;
> +	}
> +
> +	ret = (wait_for_completion_timeout(
> +		&ctx.done, msecs_to_jiffies(USB_CTRL_SET_TIMEOUT)));
> +	if (ret < 0) {
> +		usb_kill_urb(dev->urb);
> +		hid_err(hdev, "urb submission timed out");
> +	} else {
> +		ret = dev->urb->actual_length;
> +		memcpy(resp, dev->buf_in, ret);
> +	}
> +
> +err:
> +	mutex_unlock(&dev->lock);
> +
> +	return ret;
> +}

<...>

> +static int u2fzero_rng_read(struct hwrng *rng, void *data,
> +			    size_t max, bool wait)
> +{
> +	struct u2fzero_device *dev = container_of(rng,
> +		struct u2fzero_device, hwrng);
> +	struct u2f_hid_report req = {
> +		.report_type = 0,
> +		.msg.cid = CID_BROADCAST,
> +		.msg.init = {
> +			.cmd = U2F_CUSTOM_GET_RNG,
> +			.bcnth = 0,
> +			.bcntl = 0,
> +			.data  = {0},
> +		}
> +	};
> +	struct u2f_hid_msg resp;
> +	int ret;
> +	size_t actual_length;
> +
> +	if (!dev->present) {
> +		hid_dbg(dev->hdev, "device not present");
> +		return 0;
> +	}
> +
> +	ret = u2fzero_recv(dev, &req, &resp);
> +	if (ret < 0)
> +		return 0;
> +
> +	/* only take the minimum amount of data it is safe to take */
> +	actual_length = min3((size_t)ret - offsetof(struct u2f_hid_msg,
> +		init.data), U2F_HID_MSG_LEN(resp), max);
> +
> +	memcpy(data, resp.init.data, actual_length);
> +
> +	return actual_length;
> +}

<...>

> +static int u2fzero_init_hwrng(struct u2fzero_device *dev,
> +			      unsigned int minor)
> +{
> +	dev->rng_name = devm_kasprintf(&dev->hdev->dev, GFP_KERNEL,
> +		"%s-rng%u", DRIVER_SHORT, minor);
> +	if (dev->rng_name == NULL)
> +		return -ENOMEM;
> +
> +	dev->hwrng.name = dev->rng_name;
> +	dev->hwrng.read = u2fzero_rng_read;
> +	dev->hwrng.quality = 1;
> +
> +	return devm_hwrng_register(&dev->hdev->dev, &dev->hwrng);
> +}
> +
> +static int u2fzero_fill_in_urb(struct u2fzero_device *dev)
> +{
> +	struct hid_device *hdev = dev->hdev;
> +	struct usb_device *udev;
> +	struct usbhid_device *usbhid = hdev->driver_data;
> +	unsigned int pipe_in;
> +	struct usb_host_endpoint *ep;
> +
> +	if (dev->hdev->bus != BUS_USB)
> +		return -EINVAL;
> +
> +	udev = hid_to_usb_dev(hdev);
> +
> +	if (!usbhid->urbout || !usbhid->urbin)
> +		return -ENODEV;
> +
> +	ep = usb_pipe_endpoint(udev, usbhid->urbin->pipe);
> +	if (!ep)
> +		return -ENODEV;
> +
> +	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
> +	if (!dev->urb)
> +		return -ENOMEM;
> +
> +	pipe_in = (usbhid->urbin->pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
> +
> +	usb_fill_int_urb(dev->urb,
> +		udev,
> +		pipe_in,
> +		dev->buf_in,
> +		HID_REPORT_SIZE,
> +		u2fzero_read_callback,
> +		NULL,
> +		ep->desc.bInterval);
> +
> +	return 0;
> +}
> +
> +static int u2fzero_probe(struct hid_device *hdev,
> +			 const struct hid_device_id *id)
> +{
> +	struct u2fzero_device *dev;
> +	unsigned int minor;
> +	int ret;
> +
> +	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
> +	if (dev == NULL)
> +		return -ENOMEM;
> +
> +	dev->buf_out = devm_kmalloc(&hdev->dev,
> +		sizeof(struct u2f_hid_report), GFP_KERNEL);
> +	if (dev->buf_out == NULL)
> +		return -ENOMEM;
> +
> +	dev->buf_in = devm_kmalloc(&hdev->dev,
> +		sizeof(struct u2f_hid_msg), GFP_KERNEL);
> +	if (dev->buf_in == NULL)
> +		return -ENOMEM;
> +
> +	ret = hid_parse(hdev);
> +	if (ret)
> +		return ret;
> +
> +	dev->hdev = hdev;
> +	hid_set_drvdata(hdev, dev);
> +	mutex_init(&dev->lock);
> +
> +	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
> +	if (ret)
> +		return ret;
> +
> +	u2fzero_fill_in_urb(dev);
> +
> +	dev->present = true;
> +
> +	minor = ((struct hidraw *) hdev->hidraw)->minor;
> +
> +	ret = u2fzero_init_led(dev, minor);
> +	if (ret) {
> +		hid_hw_stop(hdev);
> +		return ret;
> +	}
> +
> +	hid_info(hdev, "U2F Zero LED initialised\n");
> +
> +	ret = u2fzero_init_hwrng(dev, minor);
> +	if (ret) {
> +		hid_hw_stop(hdev);
> +		return ret;
> +	}
> +
> +	hid_info(hdev, "U2F Zero RNG initialised\n");
> +
> +	return 0;
> +}

-- 
Cheers,
  Andrej

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH v3] HID: add driver for U2F Zero built-in LED and RNG
  2019-10-03  7:19 ` Andrej Shadura
@ 2019-10-03 15:25   ` Alan Stern
  0 siblings, 0 replies; 15+ messages in thread
From: Alan Stern @ 2019-10-03 15:25 UTC (permalink / raw)
  To: Andrej Shadura
  Cc: linux-usb, Jiří Kosina, linux-input,
	Andrzej Pietrasiewicz, kernel, Ezequiel Garcia,
	Vasily Khoruzhick

On Thu, 3 Oct 2019, Andrej Shadura wrote:

> On 01/04/2019 14:42, Andrej Shadura wrote:
> > U2F Zero supports custom commands for blinking the LED and getting data
> > from the internal hardware RNG. Expose the blinking function as a LED
> > device, and the internal hardware RNG as an HWRNG so that it can be used
> > to feed the enthropy pool.
> > 
> > Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>
> 
> I’ve been testing this with a different modification of U2F Zero,
> Nitrokey FIDO U2F, and on that device only I’m getting a kernel warning
> (see below).
> 
> > +static int u2fzero_recv(struct u2fzero_device *dev,
> > +			struct u2f_hid_report *req,
> > +			struct u2f_hid_msg *resp)
> > +{
> > +	int ret;
> > +	struct hid_device *hdev = dev->hdev;
> > +	struct u2fzero_transfer_context ctx;
> > +
> > +	mutex_lock(&dev->lock);
> > +
> > +	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
> > +
> > +	dev->urb->context = &ctx;
> > +	init_completion(&ctx.done);
> > +
> > +	ret = usb_submit_urb(dev->urb, GFP_NOIO);
> 
> Here, usb_submit_urb() returns EBUSY in the first attempt to read random
> numbers from the device:
> 
> URB ffff917256d5d540 submitted while active
> WARNING: CPU: 3 PID: 31 at drivers/usb/core/urb.c:363
> usb_submit_urb+0x4c2/0x5b0
> <...>
> Call Trace:
>  u2fzero_rng_read+0x16e/0x340 [hid_u2fzero]
>  ? ttwu_do_activate+0x67/0x90
>  add_early_randomness+0x53/0xc0
>  hwrng_register+0x175/0x180
>  devm_hwrng_register+0x41/0x7e
>  u2fzero_probe+0x2dd/0x350 [hid_u2fzero]
>  hid_device_probe+0x119/0x180 [hid]
>  really_probe+0xfe/0x3b0
>  driver_probe_device+0xba/0x100
>  __device_attach_driver+0x97/0x100
> 
> I don’t understand why since 1) it’s likely to be the first transmission
> of this URB, 2) there’s a mutex locked just before it. I received a
> comment from a colleague mentioning I’m probably not using the mutex
> correctly, but I don’t understand why.
> 
> I’m trying to figure this out, so I’d welcome any help with it.

You can try using usbmon to see exactly what URBs are actually running.

Alan Stern


^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, back to index

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-01 12:42 [v3] HID: add driver for U2F Zero built-in LED and RNG Andrej Shadura
2019-04-10 12:02 ` Jiri Kosina
2019-04-10 12:02   ` [PATCH v3] " Jiri Kosina
2019-04-11  9:58   ` [v3] " Benjamin Tissoires
2019-04-11  9:58     ` [PATCH v3] " Benjamin Tissoires
2019-04-11 10:35     ` [v3] " Jiri Kosina
2019-04-11 10:35       ` [PATCH v3] " Jiri Kosina
2019-04-11 11:52       ` [v3] " Andrej Shadura
2019-04-11 11:52         ` [PATCH v3] " Andrej Shadura
2019-04-17 14:43         ` [v3] " Jiri Kosina
2019-04-17 14:43           ` [PATCH v3] " Jiri Kosina
2019-04-17 14:47           ` [v3] " Andrej Shadura
2019-04-17 14:47             ` [PATCH v3] " Andrej Shadura
2019-10-03  7:19 ` Andrej Shadura
2019-10-03 15:25   ` Alan Stern

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