[linux.git] / drivers / hid / hid-u2fzero.c

// SPDX-License-Identifier: GPL-2.0
/*
 * U2F Zero LED and RNG driver
 *
 * Copyright 2018 Andrej Shadura <[email protected]>
 * 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;

	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;

	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 <[email protected]>");
MODULE_DESCRIPTION("U2F Zero LED and RNG driver");
Commit	Line	Data
42337b9d AS	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* U2F Zero LED and RNG driver
	4	*
	5	* Copyright 2018 Andrej Shadura <[email protected]>
	6	* Loosely based on drivers/hid/hid-led.c
	7	* and drivers/usb/misc/chaoskey.c
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License as
	11	* published by the Free Software Foundation, version 2.
	12	*/
	13
	14	#include <linux/hid.h>
	15	#include <linux/hidraw.h>
	16	#include <linux/hw_random.h>
	17	#include <linux/leds.h>
	18	#include <linux/module.h>
	19	#include <linux/mutex.h>
	20	#include <linux/usb.h>
	21
	22	#include "usbhid/usbhid.h"
	23	#include "hid-ids.h"
	24
	25	#define DRIVER_SHORT "u2fzero"
	26
	27	#define HID_REPORT_SIZE 64
	28
	29	/* We only use broadcast (CID-less) messages */
	30	#define CID_BROADCAST 0xffffffff
	31
	32	struct u2f_hid_msg {
	33	u32 cid;
	34	union {
	35	struct {
	36	u8 cmd;
	37	u8 bcnth;
	38	u8 bcntl;
	39	u8 data[HID_REPORT_SIZE - 7];
	40	} init;
	41	struct {
	42	u8 seq;
	43	u8 data[HID_REPORT_SIZE - 5];
	44	} cont;
	45	};
	46	} __packed;
	47
	48	struct u2f_hid_report {
	49	u8 report_type;
	50	struct u2f_hid_msg msg;
	51	} __packed;
	52
	53	#define U2F_HID_MSG_LEN(f) (size_t)(((f).init.bcnth << 8) + (f).init.bcntl)
	54
	55	/* Custom extensions to the U2FHID protocol */
	56	#define U2F_CUSTOM_GET_RNG 0x21
	57	#define U2F_CUSTOM_WINK 0x24
	58
	59	struct u2fzero_device {
	60	struct hid_device *hdev;
	61	struct urb urb; / URB for the RNG data */
	62	struct led_classdev ldev; /* Embedded struct for led */
	63	struct hwrng hwrng; /* Embedded struct for hwrng */
	64	char *led_name;
65	char *rng_name;
66	u8 *buf_out;
67	u8 *buf_in;
68	struct mutex lock;
69	bool present;
70	};
71
72	static int u2fzero_send(struct u2fzero_device dev, struct u2f_hid_report req)
73	{
74	int ret;
75
76	mutex_lock(&dev->lock);
77
78	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
79
80	ret = hid_hw_output_report(dev->hdev, dev->buf_out,
81	sizeof(struct u2f_hid_msg));
82
83	mutex_unlock(&dev->lock);
84
85	if (ret < 0)
86	return ret;
87
88	return ret == sizeof(struct u2f_hid_msg) ? 0 : -EMSGSIZE;
89	}
90
91	struct u2fzero_transfer_context {
92	struct completion done;
93	int status;
94	};
95
96	static void u2fzero_read_callback(struct urb *urb)
97	{
98	struct u2fzero_transfer_context *ctx = urb->context;
99
100	ctx->status = urb->status;
101	complete(&ctx->done);
102	}
103
104	static int u2fzero_recv(struct u2fzero_device *dev,
105	struct u2f_hid_report *req,
106	struct u2f_hid_msg *resp)
107	{
108	int ret;
109	struct hid_device *hdev = dev->hdev;
110	struct u2fzero_transfer_context ctx;
111
112	mutex_lock(&dev->lock);
113
114	memcpy(dev->buf_out, req, sizeof(struct u2f_hid_report));
115
116	dev->urb->context = &ctx;
117	init_completion(&ctx.done);
118
119	ret = usb_submit_urb(dev->urb, GFP_NOIO);
120	if (unlikely(ret)) {
121	hid_err(hdev, "usb_submit_urb failed: %d", ret);
122	goto err;
123	}
124
125	ret = hid_hw_output_report(dev->hdev, dev->buf_out,
126	sizeof(struct u2f_hid_msg));
127
128	if (ret < 0) {
129	hid_err(hdev, "hid_hw_output_report failed: %d", ret);
130	goto err;
131	}
132
133	ret = (wait_for_completion_timeout(
134	&ctx.done, msecs_to_jiffies(USB_CTRL_SET_TIMEOUT)));
135	if (ret < 0) {
136	usb_kill_urb(dev->urb);
137	hid_err(hdev, "urb submission timed out");
138	} else {
139	ret = dev->urb->actual_length;
140	memcpy(resp, dev->buf_in, ret);
141	}
142
143	err:
144	mutex_unlock(&dev->lock);
145
146	return ret;
147	}
148
149	static int u2fzero_blink(struct led_classdev *ldev)
150	{
151	struct u2fzero_device *dev = container_of(ldev,
152	struct u2fzero_device, ldev);
153	struct u2f_hid_report req = {
154	.report_type = 0,
155	.msg.cid = CID_BROADCAST,
156	.msg.init = {
157	.cmd = U2F_CUSTOM_WINK,
158	.bcnth = 0,
159	.bcntl = 0,
160	.data = {0},
161	}
162	};
163	return u2fzero_send(dev, &req);
164	}
165
166	static int u2fzero_brightness_set(struct led_classdev *ldev,
167	enum led_brightness brightness)
168	{
169	ldev->brightness = LED_OFF;
170	if (brightness)
171	return u2fzero_blink(ldev);
172	else
173	return 0;
174	}
175
176	static int u2fzero_rng_read(struct hwrng rng, void data,
177	size_t max, bool wait)
178	{
179	struct u2fzero_device *dev = container_of(rng,
180	struct u2fzero_device, hwrng);
181	struct u2f_hid_report req = {
182	.report_type = 0,
183	.msg.cid = CID_BROADCAST,
184	.msg.init = {
185	.cmd = U2F_CUSTOM_GET_RNG,
186	.bcnth = 0,
187	.bcntl = 0,
188	.data = {0},
189	}
190	};
191	struct u2f_hid_msg resp;
192	int ret;
193	size_t actual_length;
194
195	if (!dev->present) {
196	hid_dbg(dev->hdev, "device not present");
197	return 0;
198	}
199
200	ret = u2fzero_recv(dev, &req, &resp);
201	if (ret < 0)
202	return 0;
203
204	/* only take the minimum amount of data it is safe to take */
205	actual_length = min3((size_t)ret - offsetof(struct u2f_hid_msg,
206	init.data), U2F_HID_MSG_LEN(resp), max);
207
208	memcpy(data, resp.init.data, actual_length);
209
210	return actual_length;
211	}
212
213	static int u2fzero_init_led(struct u2fzero_device *dev,
214	unsigned int minor)
215	{
216	dev->led_name = devm_kasprintf(&dev->hdev->dev, GFP_KERNEL,
217	"%s%u", DRIVER_SHORT, minor);
218	if (dev->led_name == NULL)
219	return -ENOMEM;
220
221	dev->ldev.name = dev->led_name;
222	dev->ldev.max_brightness = LED_ON;
223	dev->ldev.flags = LED_HW_PLUGGABLE;
224	dev->ldev.brightness_set_blocking = u2fzero_brightness_set;
225
226	return devm_led_classdev_register(&dev->hdev->dev, &dev->ldev);
227	}
228
229	static int u2fzero_init_hwrng(struct u2fzero_device *dev,
230	unsigned int minor)
231	{
232	dev->rng_name = devm_kasprintf(&dev->hdev->dev, GFP_KERNEL,
233	"%s-rng%u", DRIVER_SHORT, minor);
234	if (dev->rng_name == NULL)
235	return -ENOMEM;
236
237	dev->hwrng.name = dev->rng_name;
238	dev->hwrng.read = u2fzero_rng_read;
239	dev->hwrng.quality = 1;
240
241	return devm_hwrng_register(&dev->hdev->dev, &dev->hwrng);
242	}
243
244	static int u2fzero_fill_in_urb(struct u2fzero_device *dev)
245	{
246	struct hid_device *hdev = dev->hdev;
247	struct usb_device *udev;
248	struct usbhid_device *usbhid = hdev->driver_data;
249	unsigned int pipe_in;
250	struct usb_host_endpoint *ep;
251
252	if (dev->hdev->bus != BUS_USB)
253	return -EINVAL;
254
255	udev = hid_to_usb_dev(hdev);
256
257	if (!usbhid->urbout \|\| !usbhid->urbin)
258	return -ENODEV;
259
260	ep = usb_pipe_endpoint(udev, usbhid->urbin->pipe);
261	if (!ep)
262	return -ENODEV;
263
264	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
265	if (!dev->urb)
266	return -ENOMEM;
267
268	pipe_in = (usbhid->urbin->pipe & ~(3 << 30)) \| (PIPE_INTERRUPT << 30);
269
270	usb_fill_int_urb(dev->urb,
271	udev,
272	pipe_in,
273	dev->buf_in,
274	HID_REPORT_SIZE,
275	u2fzero_read_callback,
276	NULL,
277	ep->desc.bInterval);
278
279	return 0;
280	}
281
282	static int u2fzero_probe(struct hid_device *hdev,
283	const struct hid_device_id *id)
284	{
285	struct u2fzero_device *dev;
286	unsigned int minor;
287	int ret;
288
59579a8d JK	289	if (!hid_is_using_ll_driver(hdev, &usb_hid_driver))
	290	return -EINVAL;
	291
42337b9d AS	292	dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
	293	if (dev == NULL)
	294	return -ENOMEM;
	295
	296	dev->buf_out = devm_kmalloc(&hdev->dev,
	297	sizeof(struct u2f_hid_report), GFP_KERNEL);
	298	if (dev->buf_out == NULL)
	299	return -ENOMEM;
	300
	301	dev->buf_in = devm_kmalloc(&hdev->dev,
	302	sizeof(struct u2f_hid_msg), GFP_KERNEL);
	303	if (dev->buf_in == NULL)
	304	return -ENOMEM;
	305
	306	ret = hid_parse(hdev);
	307	if (ret)
	308	return ret;
	309
	310	dev->hdev = hdev;
	311	hid_set_drvdata(hdev, dev);
	312	mutex_init(&dev->lock);
	313
	314	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
	315	if (ret)
	316	return ret;
	317
	318	u2fzero_fill_in_urb(dev);
	319
	320	dev->present = true;
	321
	322	minor = ((struct hidraw *) hdev->hidraw)->minor;
	323
	324	ret = u2fzero_init_led(dev, minor);
	325	if (ret) {
	326	hid_hw_stop(hdev);
	327	return ret;
	328	}
	329
	330	hid_info(hdev, "U2F Zero LED initialised\n");
	331
	332	ret = u2fzero_init_hwrng(dev, minor);
	333	if (ret) {
	334	hid_hw_stop(hdev);
	335	return ret;
	336	}
	337
	338	hid_info(hdev, "U2F Zero RNG initialised\n");
	339
	340	return 0;
	341	}
	342
	343	static void u2fzero_remove(struct hid_device *hdev)
	344	{
	345	struct u2fzero_device *dev = hid_get_drvdata(hdev);
	346
	347	mutex_lock(&dev->lock);
	348	dev->present = false;
	349	mutex_unlock(&dev->lock);
	350
	351	hid_hw_stop(hdev);
	352	usb_poison_urb(dev->urb);
	353	usb_free_urb(dev->urb);
	354	}
	355
356	static const struct hid_device_id u2fzero_table[] = {
357	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL,
358	USB_DEVICE_ID_U2F_ZERO) },
359	{ }
360	};
361	MODULE_DEVICE_TABLE(hid, u2fzero_table);
362
363	static struct hid_driver u2fzero_driver = {
364	.name = "hid-" DRIVER_SHORT,
365	.probe = u2fzero_probe,
366	.remove = u2fzero_remove,
367	.id_table = u2fzero_table,
368	};
369
370	module_hid_driver(u2fzero_driver);
371
372	MODULE_LICENSE("GPL");
373	MODULE_AUTHOR("Andrej Shadura <[email protected]>");
374	MODULE_DESCRIPTION("U2F Zero LED and RNG driver");