usb: Add driver for Altus Metrum ChaosKey device (v2)
This is a hardware random number generator. The driver provides both a /dev/chaoskeyX entry and hooks the entropy source up to the kernel hwrng interface. More information about the device can be found at http://chaoskey.org The USB ID for ChaosKey was allocated from the OpenMoko USB vendor space and is visible as 'USBtrng' here: http://wiki.openmoko.org/wiki/USB_Product_IDs v2: Respond to review from Oliver Neukum <oneukum@suse.de> * Delete extensive debug infrastructure and replace it with calls to dev_dbg. * Allocate I/O buffer separately from device structure to obey requirements for non-coherant architectures. * Initialize mutexes before registering device to ensure that open cannot be invoked before the device is ready to proceed. * Return number of bytes read instead of -EINTR when partial read operation is aborted due to a signal. * Make sure device mutex is unlocked in read error paths. * Add MAINTAINERS entry for the driver Signed-off-by: Keith Packard <keithp@keithp.com> Cc: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Keith Packard
Greg Kroah-Hartman
Родитель
1fcefbdf06
Коммит
66e3e59189
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@ -10129,6 +10129,12 @@ S: Maintained
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F: drivers/net/usb/cdc_*.c
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F: include/uapi/linux/usb/cdc.h
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USB CHAOSKEY DRIVER
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M: Keith Packard <keithp@keithp.com>
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L: linux-usb@vger.kernel.org
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S: Maintained
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F: drivers/usb/misc/chaoskey.c
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USB CYPRESS C67X00 DRIVER
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M: Peter Korsgaard <jacmet@sunsite.dk>
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L: linux-usb@vger.kernel.org
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@ -255,3 +255,15 @@ config USB_LINK_LAYER_TEST
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This driver is for generating specific traffic for Super Speed Link
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Layer Test Device. Say Y only when you want to conduct USB Super Speed
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Link Layer Test for host controllers.
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config USB_CHAOSKEY
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tristate "ChaosKey random number generator driver support"
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help
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Say Y here if you want to connect an AltusMetrum ChaosKey to
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your computer's USB port. The ChaosKey is a hardware random
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number generator which hooks into the kernel entropy pool to
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ensure a large supply of entropy for /dev/random and
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/dev/urandom and also provides direct access via /dev/chaoskeyX
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To compile this driver as a module, choose M here: the
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module will be called chaoskey.
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@ -25,6 +25,7 @@ obj-$(CONFIG_USB_USS720) += uss720.o
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obj-$(CONFIG_USB_SEVSEG) += usbsevseg.o
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obj-$(CONFIG_USB_YUREX) += yurex.o
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obj-$(CONFIG_USB_HSIC_USB3503) += usb3503.o
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obj-$(CONFIG_USB_CHAOSKEY) += chaoskey.o
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obj-$(CONFIG_USB_SISUSBVGA) += sisusbvga/
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obj-$(CONFIG_USB_LINK_LAYER_TEST) += lvstest.o
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@ -0,0 +1,530 @@
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/*
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* chaoskey - driver for ChaosKey device from Altus Metrum.
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*
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* This device provides true random numbers using a noise source based
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* on a reverse-biased p-n junction in avalanche breakdown. More
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* details can be found at http://chaoskey.org
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*
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* The driver connects to the kernel hardware RNG interface to provide
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* entropy for /dev/random and other kernel activities. It also offers
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* a separate /dev/ entry to allow for direct access to the random
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* bit stream.
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*
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* Copyright © 2015 Keith Packard <keithp@keithp.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/usb.h>
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#include <linux/wait.h>
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#include <linux/hw_random.h>
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static struct usb_driver chaoskey_driver;
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static struct usb_class_driver chaoskey_class;
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static int chaoskey_rng_read(struct hwrng *rng, void *data,
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size_t max, bool wait);
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#define usb_dbg(usb_if, format, arg...) \
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dev_dbg(&(usb_if)->dev, format, ## arg)
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#define usb_err(usb_if, format, arg...) \
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dev_err(&(usb_if)->dev, format, ## arg)
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/* Version Information */
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#define DRIVER_VERSION "v0.1"
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#define DRIVER_AUTHOR "Keith Packard, keithp@keithp.com"
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#define DRIVER_DESC "Altus Metrum ChaosKey driver"
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#define DRIVER_SHORT "chaoskey"
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MODULE_VERSION(DRIVER_VERSION);
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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#define CHAOSKEY_VENDOR_ID 0x1d50 /* OpenMoko */
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#define CHAOSKEY_PRODUCT_ID 0x60c6 /* ChaosKey */
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#define CHAOSKEY_BUF_LEN 64 /* max size of USB full speed packet */
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#define NAK_TIMEOUT (HZ) /* stall/wait timeout for device */
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#ifdef CONFIG_USB_DYNAMIC_MINORS
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#define USB_CHAOSKEY_MINOR_BASE 0
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#else
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/* IOWARRIOR_MINOR_BASE + 16, not official yet */
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#define USB_CHAOSKEY_MINOR_BASE 224
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#endif
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static const struct usb_device_id chaoskey_table[] = {
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{ USB_DEVICE(CHAOSKEY_VENDOR_ID, CHAOSKEY_PRODUCT_ID) },
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{ },
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};
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MODULE_DEVICE_TABLE(usb, chaoskey_table);
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/* Driver-local specific stuff */
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struct chaoskey {
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struct usb_interface *interface;
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char in_ep;
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struct mutex lock;
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struct mutex rng_lock;
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int open; /* open count */
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int present; /* device not disconnected */
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int size; /* size of buf */
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int valid; /* bytes of buf read */
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int used; /* bytes of buf consumed */
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char *name; /* product + serial */
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struct hwrng hwrng; /* Embedded struct for hwrng */
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int hwrng_registered; /* registered with hwrng API */
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wait_queue_head_t wait_q; /* for timeouts */
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char *buf;
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};
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static void chaoskey_free(struct chaoskey *dev)
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{
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usb_dbg(dev->interface, "free");
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kfree(dev->name);
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kfree(dev->buf);
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kfree(dev);
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}
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static int chaoskey_probe(struct usb_interface *interface,
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const struct usb_device_id *id)
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{
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struct usb_device *udev = interface_to_usbdev(interface);
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struct usb_host_interface *altsetting = interface->cur_altsetting;
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int i;
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int in_ep = -1;
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struct chaoskey *dev;
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int result;
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int size;
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usb_dbg(interface, "probe %s-%s", udev->product, udev->serial);
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/* Find the first bulk IN endpoint and its packet size */
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for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
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if (usb_endpoint_is_bulk_in(&altsetting->endpoint[i].desc)) {
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in_ep = altsetting->endpoint[i].desc.bEndpointAddress;
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size = altsetting->endpoint[i].desc.wMaxPacketSize;
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break;
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}
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}
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/* Validate endpoint and size */
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if (in_ep == -1) {
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usb_dbg(interface, "no IN endpoint found");
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return -ENODEV;
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}
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if (size <= 0) {
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usb_dbg(interface, "invalid size (%d)", size);
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return -ENODEV;
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}
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if (size > CHAOSKEY_BUF_LEN) {
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usb_dbg(interface, "size reduced from %d to %d\n",
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size, CHAOSKEY_BUF_LEN);
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size = CHAOSKEY_BUF_LEN;
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}
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/* Looks good, allocate and initialize */
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dev = kzalloc(sizeof(struct chaoskey), GFP_KERNEL);
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if (dev == NULL)
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return -ENOMEM;
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dev->buf = kmalloc(size, GFP_KERNEL);
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if (dev->buf == NULL) {
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kfree(dev);
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return -ENOMEM;
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}
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/* Construct a name using the product and serial values. Each
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* device needs a unique name for the hwrng code
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*/
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if (udev->product && udev->serial) {
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dev->name = kmalloc(strlen(udev->product) + 1 +
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strlen(udev->serial) + 1, GFP_KERNEL);
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if (dev->name == NULL) {
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kfree(dev->buf);
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kfree(dev);
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return -ENOMEM;
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}
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strcpy(dev->name, udev->product);
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strcat(dev->name, "-");
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strcat(dev->name, udev->serial);
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}
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dev->interface = interface;
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dev->in_ep = in_ep;
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dev->size = size;
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dev->present = 1;
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init_waitqueue_head(&dev->wait_q);
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mutex_init(&dev->lock);
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mutex_init(&dev->rng_lock);
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usb_set_intfdata(interface, dev);
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result = usb_register_dev(interface, &chaoskey_class);
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if (result) {
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usb_err(interface, "Unable to allocate minor number.");
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usb_set_intfdata(interface, NULL);
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chaoskey_free(dev);
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return result;
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}
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dev->hwrng.name = dev->name ? dev->name : chaoskey_driver.name;
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dev->hwrng.read = chaoskey_rng_read;
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/* Set the 'quality' metric. Quality is measured in units of
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* 1/1024's of a bit ("mills"). This should be set to 1024,
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* but there is a bug in the hwrng core which masks it with
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* 1023.
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*
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* The patch that has been merged to the crypto development
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* tree for that bug limits the value to 1024 at most, so by
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* setting this to 1024 + 1023, we get 1023 before the fix is
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* merged and 1024 afterwards. We'll patch this driver once
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* both bits of code are in the same tree.
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*/
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dev->hwrng.quality = 1024 + 1023;
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dev->hwrng_registered = (hwrng_register(&dev->hwrng) == 0);
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if (!dev->hwrng_registered)
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usb_err(interface, "Unable to register with hwrng");
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usb_enable_autosuspend(udev);
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usb_dbg(interface, "chaoskey probe success, size %d", dev->size);
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return 0;
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}
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static void chaoskey_disconnect(struct usb_interface *interface)
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{
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struct chaoskey *dev;
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usb_dbg(interface, "disconnect");
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dev = usb_get_intfdata(interface);
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if (!dev) {
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usb_dbg(interface, "disconnect failed - no dev");
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return;
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}
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if (dev->hwrng_registered)
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hwrng_unregister(&dev->hwrng);
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usb_deregister_dev(interface, &chaoskey_class);
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usb_set_intfdata(interface, NULL);
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mutex_lock(&dev->lock);
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dev->present = 0;
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if (!dev->open) {
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mutex_unlock(&dev->lock);
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chaoskey_free(dev);
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} else
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mutex_unlock(&dev->lock);
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usb_dbg(interface, "disconnect done");
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}
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static int chaoskey_open(struct inode *inode, struct file *file)
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{
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struct chaoskey *dev;
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struct usb_interface *interface;
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/* get the interface from minor number and driver information */
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interface = usb_find_interface(&chaoskey_driver, iminor(inode));
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if (!interface)
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return -ENODEV;
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usb_dbg(interface, "open");
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dev = usb_get_intfdata(interface);
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if (!dev) {
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usb_dbg(interface, "open (dev)");
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return -ENODEV;
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}
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file->private_data = dev;
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mutex_lock(&dev->lock);
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++dev->open;
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mutex_unlock(&dev->lock);
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usb_dbg(interface, "open success");
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return 0;
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}
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static int chaoskey_release(struct inode *inode, struct file *file)
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{
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struct chaoskey *dev = file->private_data;
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struct usb_interface *interface;
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if (dev == NULL)
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return -ENODEV;
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interface = dev->interface;
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usb_dbg(interface, "release");
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mutex_lock(&dev->lock);
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usb_dbg(interface, "open count at release is %d", dev->open);
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if (dev->open <= 0) {
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usb_dbg(interface, "invalid open count (%d)", dev->open);
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mutex_unlock(&dev->lock);
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return -ENODEV;
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}
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--dev->open;
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if (!dev->present) {
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if (dev->open == 0) {
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mutex_unlock(&dev->lock);
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chaoskey_free(dev);
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} else
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mutex_unlock(&dev->lock);
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} else
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mutex_unlock(&dev->lock);
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usb_dbg(interface, "release success");
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return 0;
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}
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/* Fill the buffer. Called with dev->lock held
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*/
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static int _chaoskey_fill(struct chaoskey *dev)
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{
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DEFINE_WAIT(wait);
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int result;
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int this_read;
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struct usb_device *udev = interface_to_usbdev(dev->interface);
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usb_dbg(dev->interface, "fill");
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/* Return immediately if someone called before the buffer was
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* empty */
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if (dev->valid != dev->used) {
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usb_dbg(dev->interface, "not empty yet (valid %d used %d)",
|
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dev->valid, dev->used);
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return 0;
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}
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||||
|
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/* Bail if the device has been removed */
|
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if (!dev->present) {
|
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usb_dbg(dev->interface, "device not present");
|
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return -ENODEV;
|
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}
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|
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/* Make sure the device is awake */
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result = usb_autopm_get_interface(dev->interface);
|
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if (result) {
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usb_dbg(dev->interface, "wakeup failed (result %d)", result);
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return result;
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}
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result = usb_bulk_msg(udev,
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usb_rcvbulkpipe(udev, dev->in_ep),
|
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dev->buf, dev->size, &this_read,
|
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NAK_TIMEOUT);
|
||||
|
||||
/* Let the device go back to sleep eventually */
|
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usb_autopm_put_interface(dev->interface);
|
||||
|
||||
if (result == 0) {
|
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dev->valid = this_read;
|
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dev->used = 0;
|
||||
}
|
||||
|
||||
usb_dbg(dev->interface, "bulk_msg result %d this_read %d",
|
||||
result, this_read);
|
||||
|
||||
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) {
|
||||
mutex_unlock(&dev->lock);
|
||||
goto bail;
|
||||
}
|
||||
|
||||
/* Read returned zero bytes */
|
||||
if (dev->used == dev->valid) {
|
||||
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);
|
||||
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, 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)
|
||||
{
|
||||
usb_dbg(interface, "resume");
|
||||
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);
|
||||
|
||||
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