On 12/11/2018 03:17, Jiri Kosina wrote:
> On Thu, 1 Nov 2018, Andrej Shadura wrote:
>
>> Hi everyone,
>>
>> I’ve got a comment from Nick Kossifidis that I probably shouldn’t set
>> RNG’s quality to 1024. Adding linux-crypto@ to the loop.
>
> So, what was this about? Is there any resolution to it? :)
So far, not really. I talked to Keith Packard regarding a similar
setting in his ChaosKey driver, and I understand his opinion is that it
is appropriate there since he’s convinced about the quality of the
hardware he designed. I’m not sure what exactly I should set it to here.
>>
>> On 23/10/2018 16:46, 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.shad...@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 61e1953ff921..3de6bf202f20 100644
>>> --- a/drivers/hid/Kconfig
>>> +++ b/drivers/hid/Kconfig
>>> @@ -975,6 +975,21 @@ 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 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 bd7ac53b75c5..617b1a928b6a 100644
>>> --- a/drivers/hid/Makefile
>>> +++ b/drivers/hid/Makefile
>>> @@ -107,6 +107,7 @@ 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 bc49909aba8e..070a2fcd8a18 100644
>>> --- a/drivers/hid/hid-ids.h
>>> +++ b/drivers/hid/hid-ids.h
>>> @@ -309,6 +309,7 @@
>>> #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..bd4077c93c97
>>> --- /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 <and...@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 = 1024;
>>> +
>>> + 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 <and...@shadura.me>");
>>> +MODULE_DESCRIPTION("U2F Zero LED and RNG driver");
>>>
>>
>>
>> --
>> Cheers,
>> Andrej
>>
>
--
Cheers,
Andrej
