Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 584 insertions, 0 deletions

diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
new file mode 100644
index 000000000..87067c3d6
--- /dev/null
+++ b/drivers/usb/misc/chaoskey.c
@@ -0,0 +1,584 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * chaoskey - driver for ChaosKey device from Altus Metrum.
+ *
+ * This device provides true random numbers using a noise source based
+ * on a reverse-biased p-n junction in avalanche breakdown. More
+ * details can be found at http://chaoskey.org
+ *
+ * The driver connects to the kernel hardware RNG interface to provide
+ * entropy for /dev/random and other kernel activities. It also offers
+ * a separate /dev/ entry to allow for direct access to the random
+ * bit stream.
+ *
+ * Copyright © 2015 Keith Packard <keithp@keithp.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+#include <linux/hw_random.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+
+static struct usb_driver chaoskey_driver;
+static struct usb_class_driver chaoskey_class;
+static int chaoskey_rng_read(struct hwrng *rng, void *data,
+			     size_t max, bool wait);
+
+#define usb_dbg(usb_if, format, arg...) \
+	dev_dbg(&(usb_if)->dev, format, ## arg)
+
+#define usb_err(usb_if, format, arg...) \
+	dev_err(&(usb_if)->dev, format, ## arg)
+
+/* Version Information */
+#define DRIVER_AUTHOR	"Keith Packard, keithp@keithp.com"
+#define DRIVER_DESC	"Altus Metrum ChaosKey driver"
+#define DRIVER_SHORT	"chaoskey"
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+#define CHAOSKEY_VENDOR_ID	0x1d50	/* OpenMoko */
+#define CHAOSKEY_PRODUCT_ID	0x60c6	/* ChaosKey */
+
+#define ALEA_VENDOR_ID		0x12d8	/* Araneus */
+#define ALEA_PRODUCT_ID		0x0001	/* Alea I */
+
+#define CHAOSKEY_BUF_LEN	64	/* max size of USB full speed packet */
+
+#define NAK_TIMEOUT (HZ)		/* normal stall/wait timeout */
+#define ALEA_FIRST_TIMEOUT (HZ*3)	/* first stall/wait timeout for Alea */
+
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+#define USB_CHAOSKEY_MINOR_BASE 0
+#else
+
+/* IOWARRIOR_MINOR_BASE + 16, not official yet */
+#define USB_CHAOSKEY_MINOR_BASE 224
+#endif
+
+static const struct usb_device_id chaoskey_table[] = {
+	{ USB_DEVICE(CHAOSKEY_VENDOR_ID, CHAOSKEY_PRODUCT_ID) },
+	{ USB_DEVICE(ALEA_VENDOR_ID, ALEA_PRODUCT_ID) },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, chaoskey_table);
+
+static void chaos_read_callback(struct urb *urb);
+
+/* Driver-local specific stuff */
+struct chaoskey {
+	struct usb_interface *interface;
+	char in_ep;
+	struct mutex lock;
+	struct mutex rng_lock;
+	int open;			/* open count */
+	bool present;			/* device not disconnected */
+	bool reading;			/* ongoing IO */
+	bool reads_started;		/* track first read for Alea */
+	int size;			/* size of buf */
+	int valid;			/* bytes of buf read */
+	int used;			/* bytes of buf consumed */
+	char *name;			/* product + serial */
+	struct hwrng hwrng;		/* Embedded struct for hwrng */
+	int hwrng_registered;		/* registered with hwrng API */
+	wait_queue_head_t wait_q;	/* for timeouts */
+	struct urb *urb;		/* for performing IO */
+	char *buf;
+};
+
+static void chaoskey_free(struct chaoskey *dev)
+{
+	if (dev) {
+		usb_dbg(dev->interface, "free");
+		usb_free_urb(dev->urb);
+		kfree(dev->name);
+		kfree(dev->buf);
+		usb_put_intf(dev->interface);
+		kfree(dev);
+	}
+}
+
+static int chaoskey_probe(struct usb_interface *interface,
+			  const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct usb_host_interface *altsetting = interface->cur_altsetting;
+	struct usb_endpoint_descriptor *epd;
+	int in_ep;
+	struct chaoskey *dev;
+	int result = -ENOMEM;
+	int size;
+	int res;
+
+	usb_dbg(interface, "probe %s-%s", udev->product, udev->serial);
+
+	/* Find the first bulk IN endpoint and its packet size */
+	res = usb_find_bulk_in_endpoint(altsetting, &epd);
+	if (res) {
+		usb_dbg(interface, "no IN endpoint found");
+		return res;
+	}
+
+	in_ep = usb_endpoint_num(epd);
+	size = usb_endpoint_maxp(epd);
+
+	/* Validate endpoint and size */
+	if (size <= 0) {
+		usb_dbg(interface, "invalid size (%d)", size);
+		return -ENODEV;
+	}
+
+	if (size > CHAOSKEY_BUF_LEN) {
+		usb_dbg(interface, "size reduced from %d to %d\n",
+			size, CHAOSKEY_BUF_LEN);
+		size = CHAOSKEY_BUF_LEN;
+	}
+
+	/* Looks good, allocate and initialize */
+
+	dev = kzalloc(sizeof(struct chaoskey), GFP_KERNEL);
+
+	if (dev == NULL)
+		goto out;
+
+	dev->interface = usb_get_intf(interface);
+
+	dev->buf = kmalloc(size, GFP_KERNEL);
+
+	if (dev->buf == NULL)
+		goto out;
+
+	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!dev->urb)
+		goto out;
+
+	usb_fill_bulk_urb(dev->urb,
+		udev,
+		usb_rcvbulkpipe(udev, in_ep),
+		dev->buf,
+		size,
+		chaos_read_callback,
+		dev);
+
+	/* Construct a name using the product and serial values. Each
+	 * device needs a unique name for the hwrng code
+	 */
+
+	if (udev->product && udev->serial) {
+		dev->name = kasprintf(GFP_KERNEL, "%s-%s", udev->product,
+				      udev->serial);
+		if (dev->name == NULL)
+			goto out;
+	}
+
+	dev->in_ep = in_ep;
+
+	if (le16_to_cpu(udev->descriptor.idVendor) != ALEA_VENDOR_ID)
+		dev->reads_started = true;
+
+	dev->size = size;
+	dev->present = true;
+
+	init_waitqueue_head(&dev->wait_q);
+
+	mutex_init(&dev->lock);
+	mutex_init(&dev->rng_lock);
+
+	usb_set_intfdata(interface, dev);
+
+	result = usb_register_dev(interface, &chaoskey_class);
+	if (result) {
+		usb_err(interface, "Unable to allocate minor number.");
+		goto out;
+	}
+
+	dev->hwrng.name = dev->name ? dev->name : chaoskey_driver.name;
+	dev->hwrng.read = chaoskey_rng_read;
+	dev->hwrng.quality = 1024;
+
+	dev->hwrng_registered = (hwrng_register(&dev->hwrng) == 0);
+	if (!dev->hwrng_registered)
+		usb_err(interface, "Unable to register with hwrng");
+
+	usb_enable_autosuspend(udev);
+
+	usb_dbg(interface, "chaoskey probe success, size %d", dev->size);
+	return 0;
+
+out:
+	usb_set_intfdata(interface, NULL);
+	chaoskey_free(dev);
+	return result;
+}
+
+static void chaoskey_disconnect(struct usb_interface *interface)
+{
+	struct chaoskey	*dev;
+
+	usb_dbg(interface, "disconnect");
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		usb_dbg(interface, "disconnect failed - no dev");
+		return;
+	}
+
+	if (dev->hwrng_registered)
+		hwrng_unregister(&dev->hwrng);
+
+	usb_deregister_dev(interface, &chaoskey_class);
+
+	usb_set_intfdata(interface, NULL);
+	mutex_lock(&dev->lock);
+
+	dev->present = false;
+	usb_poison_urb(dev->urb);
+
+	if (!dev->open) {
+		mutex_unlock(&dev->lock);
+		chaoskey_free(dev);
+	} else
+		mutex_unlock(&dev->lock);
+
+	usb_dbg(interface, "disconnect done");
+}
+
+static int chaoskey_open(struct inode *inode, struct file *file)
+{
+	struct chaoskey *dev;
+	struct usb_interface *interface;
+
+	/* get the interface from minor number and driver information */
+	interface = usb_find_interface(&chaoskey_driver, iminor(inode));
+	if (!interface)
+		return -ENODEV;
+
+	usb_dbg(interface, "open");
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		usb_dbg(interface, "open (dev)");
+		return -ENODEV;
+	}
+
+	file->private_data = dev;
+	mutex_lock(&dev->lock);
+	++dev->open;
+	mutex_unlock(&dev->lock);
+
+	usb_dbg(interface, "open success");
+	return 0;
+}
+
+static int chaoskey_release(struct inode *inode, struct file *file)
+{
+	struct chaoskey *dev = file->private_data;
+	struct usb_interface *interface;
+
+	if (dev == NULL)
+		return -ENODEV;
+
+	interface = dev->interface;
+
+	usb_dbg(interface, "release");
+
+	mutex_lock(&dev->lock);
+
+	usb_dbg(interface, "open count at release is %d", dev->open);
+
+	if (dev->open <= 0) {
+		usb_dbg(interface, "invalid open count (%d)", dev->open);
+		mutex_unlock(&dev->lock);
+		return -ENODEV;
+	}
+
+	--dev->open;
+
+	if (!dev->present) {
+		if (dev->open == 0) {
+			mutex_unlock(&dev->lock);
+			chaoskey_free(dev);
+		} else
+			mutex_unlock(&dev->lock);
+	} else
+		mutex_unlock(&dev->lock);
+
+	usb_dbg(interface, "release success");
+	return 0;
+}
+
+static void chaos_read_callback(struct urb *urb)
+{
+	struct chaoskey *dev = urb->context;
+	int status = urb->status;
+
+	usb_dbg(dev->interface, "callback status (%d)", status);
+
+	if (status == 0)
+		dev->valid = urb->actual_length;
+	else
+		dev->valid = 0;
+
+	dev->used = 0;
+
+	/* must be seen first before validity is announced */
+	smp_wmb();
+
+	dev->reading = false;
+	wake_up(&dev->wait_q);
+}
+
+/* Fill the buffer. Called with dev->lock held
+ */
+static int _chaoskey_fill(struct chaoskey *dev)
+{
+	DEFINE_WAIT(wait);
+	int result;
+	bool started;
+
+	usb_dbg(dev->interface, "fill");
+
+	/* Return immediately if someone called before the buffer was
+	 * empty */
+	if (dev->valid != dev->used) {
+		usb_dbg(dev->interface, "not empty yet (valid %d used %d)",
+			dev->valid, dev->used);
+		return 0;
+	}
+
+	/* Bail if the device has been removed */
+	if (!dev->present) {
+		usb_dbg(dev->interface, "device not present");
+		return -ENODEV;
+	}
+
+	/* Make sure the device is awake */
+	result = usb_autopm_get_interface(dev->interface);
+	if (result) {
+		usb_dbg(dev->interface, "wakeup failed (result %d)", result);
+		return result;
+	}
+
+	dev->reading = true;
+	result = usb_submit_urb(dev->urb, GFP_KERNEL);
+	if (result < 0) {
+		result = usb_translate_errors(result);
+		dev->reading = false;
+		goto out;
+	}
+
+	/* The first read on the Alea takes a little under 2 seconds.
+	 * Reads after the first read take only a few microseconds
+	 * though.  Presumably the entropy-generating circuit needs
+	 * time to ramp up.  So, we wait longer on the first read.
+	 */
+	started = dev->reads_started;
+	dev->reads_started = true;
+	result = wait_event_interruptible_timeout(
+		dev->wait_q,
+		!dev->reading,
+		(started ? NAK_TIMEOUT : ALEA_FIRST_TIMEOUT) );
+
+	if (result < 0) {
+		usb_kill_urb(dev->urb);
+		goto out;
+	}
+
+	if (result == 0) {
+		result = -ETIMEDOUT;
+		usb_kill_urb(dev->urb);
+	} else {
+		result = dev->valid;
+	}
+out:
+	/* Let the device go back to sleep eventually */
+	usb_autopm_put_interface(dev->interface);
+
+	usb_dbg(dev->interface, "read %d bytes", dev->valid);
+
+	return result;
+}
+
+static ssize_t chaoskey_read(struct file *file,
+			     char __user *buffer,
+			     size_t count,
+			     loff_t *ppos)
+{
+	struct chaoskey *dev;
+	ssize_t read_count = 0;
+	int this_time;
+	int result = 0;
+	unsigned long remain;
+
+	dev = file->private_data;
+
+	if (dev == NULL || !dev->present)
+		return -ENODEV;
+
+	usb_dbg(dev->interface, "read %zu", count);
+
+	while (count > 0) {
+
+		/* Grab the rng_lock briefly to ensure that the hwrng interface
+		 * gets priority over other user access
+		 */
+		result = mutex_lock_interruptible(&dev->rng_lock);
+		if (result)
+			goto bail;
+		mutex_unlock(&dev->rng_lock);
+
+		result = mutex_lock_interruptible(&dev->lock);
+		if (result)
+			goto bail;
+		if (dev->valid == dev->used) {
+			result = _chaoskey_fill(dev);
+			if (result < 0) {
+				mutex_unlock(&dev->lock);
+				goto bail;
+			}
+		}
+
+		this_time = dev->valid - dev->used;
+		if (this_time > count)
+			this_time = count;
+
+		remain = copy_to_user(buffer, dev->buf + dev->used, this_time);
+		if (remain) {
+			result = -EFAULT;
+
+			/* Consume the bytes that were copied so we don't leak
+			 * data to user space
+			 */
+			dev->used += this_time - remain;
+			mutex_unlock(&dev->lock);
+			goto bail;
+		}
+
+		count -= this_time;
+		read_count += this_time;
+		buffer += this_time;
+		dev->used += this_time;
+		mutex_unlock(&dev->lock);
+	}
+bail:
+	if (read_count) {
+		usb_dbg(dev->interface, "read %zu bytes", read_count);
+		return read_count;
+	}
+	usb_dbg(dev->interface, "empty read, result %d", result);
+	if (result == -ETIMEDOUT)
+		result = -EAGAIN;
+	return result;
+}
+
+static int chaoskey_rng_read(struct hwrng *rng, void *data,
+			     size_t max, bool wait)
+{
+	struct chaoskey *dev = container_of(rng, struct chaoskey, hwrng);
+	int this_time;
+
+	usb_dbg(dev->interface, "rng_read max %zu wait %d", max, wait);
+
+	if (!dev->present) {
+		usb_dbg(dev->interface, "device not present");
+		return 0;
+	}
+
+	/* Hold the rng_lock until we acquire the device lock so that
+	 * this operation gets priority over other user access to the
+	 * device
+	 */
+	mutex_lock(&dev->rng_lock);
+
+	mutex_lock(&dev->lock);
+
+	mutex_unlock(&dev->rng_lock);
+
+	/* Try to fill the buffer if empty. It doesn't actually matter
+	 * if _chaoskey_fill works; we'll just return zero bytes as
+	 * the buffer will still be empty
+	 */
+	if (dev->valid == dev->used)
+		(void) _chaoskey_fill(dev);
+
+	this_time = dev->valid - dev->used;
+	if (this_time > max)
+		this_time = max;
+
+	memcpy(data, dev->buf + dev->used, this_time);
+
+	dev->used += this_time;
+
+	mutex_unlock(&dev->lock);
+
+	usb_dbg(dev->interface, "rng_read this_time %d\n", this_time);
+	return this_time;
+}
+
+#ifdef CONFIG_PM
+static int chaoskey_suspend(struct usb_interface *interface,
+			    pm_message_t message)
+{
+	usb_dbg(interface, "suspend");
+	return 0;
+}
+
+static int chaoskey_resume(struct usb_interface *interface)
+{
+	struct chaoskey *dev;
+	struct usb_device *udev = interface_to_usbdev(interface);
+
+	usb_dbg(interface, "resume");
+	dev = usb_get_intfdata(interface);
+
+	/*
+	 * We may have lost power.
+	 * In that case the device that needs a long time
+	 * for the first requests needs an extended timeout
+	 * again
+	 */
+	if (le16_to_cpu(udev->descriptor.idVendor) == ALEA_VENDOR_ID)
+		dev->reads_started = false;
+
+	return 0;
+}
+#else
+#define chaoskey_suspend NULL
+#define chaoskey_resume NULL
+#endif
+
+/* file operation pointers */
+static const struct file_operations chaoskey_fops = {
+	.owner = THIS_MODULE,
+	.read = chaoskey_read,
+	.open = chaoskey_open,
+	.release = chaoskey_release,
+	.llseek = default_llseek,
+};
+
+/* class driver information */
+static struct usb_class_driver chaoskey_class = {
+	.name = "chaoskey%d",
+	.fops = &chaoskey_fops,
+	.minor_base = USB_CHAOSKEY_MINOR_BASE,
+};
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver chaoskey_driver = {
+	.name = DRIVER_SHORT,
+	.probe = chaoskey_probe,
+	.disconnect = chaoskey_disconnect,
+	.suspend = chaoskey_suspend,
+	.resume = chaoskey_resume,
+	.reset_resume = chaoskey_resume,
+	.id_table = chaoskey_table,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(chaoskey_driver);
+