linux/drivers/usb/misc/yurex.c
Ben Hutchings 14427b8683 USB: yurex: Check for truncation in yurex_read()
snprintf() always returns the full length of the string it could have
printed, even if it was truncated because the buffer was too small.
So in case the counter value is truncated, we will over-read from
in_buffer and over-write to the caller's buffer.

I don't think it's actually possible for this to happen, but in case
truncation occurs, WARN and return -EIO.

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-05 13:27:06 +02:00

524 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Driver for Meywa-Denki & KAYAC YUREX
*
* Copyright (C) 2010 Tomoki Sekiyama (tomoki.sekiyama@gmail.com)
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/hid.h>
#define DRIVER_AUTHOR "Tomoki Sekiyama"
#define DRIVER_DESC "Driver for Meywa-Denki & KAYAC YUREX"
#define YUREX_VENDOR_ID 0x0c45
#define YUREX_PRODUCT_ID 0x1010
#define CMD_ACK '!'
#define CMD_ANIMATE 'A'
#define CMD_COUNT 'C'
#define CMD_LED 'L'
#define CMD_READ 'R'
#define CMD_SET 'S'
#define CMD_VERSION 'V'
#define CMD_EOF 0x0d
#define CMD_PADDING 0xff
#define YUREX_BUF_SIZE 8
#define YUREX_WRITE_TIMEOUT (HZ*2)
/* table of devices that work with this driver */
static struct usb_device_id yurex_table[] = {
{ USB_DEVICE(YUREX_VENDOR_ID, YUREX_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, yurex_table);
#ifdef CONFIG_USB_DYNAMIC_MINORS
#define YUREX_MINOR_BASE 0
#else
#define YUREX_MINOR_BASE 192
#endif
/* Structure to hold all of our device specific stuff */
struct usb_yurex {
struct usb_device *udev;
struct usb_interface *interface;
__u8 int_in_endpointAddr;
struct urb *urb; /* URB for interrupt in */
unsigned char *int_buffer; /* buffer for intterupt in */
struct urb *cntl_urb; /* URB for control msg */
struct usb_ctrlrequest *cntl_req; /* req for control msg */
unsigned char *cntl_buffer; /* buffer for control msg */
struct kref kref;
struct mutex io_mutex;
struct fasync_struct *async_queue;
wait_queue_head_t waitq;
spinlock_t lock;
__s64 bbu; /* BBU from device */
};
#define to_yurex_dev(d) container_of(d, struct usb_yurex, kref)
static struct usb_driver yurex_driver;
static const struct file_operations yurex_fops;
static void yurex_control_callback(struct urb *urb)
{
struct usb_yurex *dev = urb->context;
int status = urb->status;
if (status) {
dev_err(&urb->dev->dev, "%s - control failed: %d\n",
__func__, status);
wake_up_interruptible(&dev->waitq);
return;
}
/* on success, sender woken up by CMD_ACK int in, or timeout */
}
static void yurex_delete(struct kref *kref)
{
struct usb_yurex *dev = to_yurex_dev(kref);
dev_dbg(&dev->interface->dev, "%s\n", __func__);
usb_put_dev(dev->udev);
if (dev->cntl_urb) {
usb_kill_urb(dev->cntl_urb);
kfree(dev->cntl_req);
if (dev->cntl_buffer)
usb_free_coherent(dev->udev, YUREX_BUF_SIZE,
dev->cntl_buffer, dev->cntl_urb->transfer_dma);
usb_free_urb(dev->cntl_urb);
}
if (dev->urb) {
usb_kill_urb(dev->urb);
if (dev->int_buffer)
usb_free_coherent(dev->udev, YUREX_BUF_SIZE,
dev->int_buffer, dev->urb->transfer_dma);
usb_free_urb(dev->urb);
}
kfree(dev);
}
/*
* usb class driver info in order to get a minor number from the usb core,
* and to have the device registered with the driver core
*/
static struct usb_class_driver yurex_class = {
.name = "yurex%d",
.fops = &yurex_fops,
.minor_base = YUREX_MINOR_BASE,
};
static void yurex_interrupt(struct urb *urb)
{
struct usb_yurex *dev = urb->context;
unsigned char *buf = dev->int_buffer;
int status = urb->status;
unsigned long flags;
int retval, i;
switch (status) {
case 0: /*success*/
break;
case -EOVERFLOW:
dev_err(&dev->interface->dev,
"%s - overflow with length %d, actual length is %d\n",
__func__, YUREX_BUF_SIZE, dev->urb->actual_length);
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
case -EILSEQ:
/* The device is terminated, clean up */
return;
default:
dev_err(&dev->interface->dev,
"%s - unknown status received: %d\n", __func__, status);
goto exit;
}
/* handle received message */
switch (buf[0]) {
case CMD_COUNT:
case CMD_READ:
if (buf[6] == CMD_EOF) {
spin_lock_irqsave(&dev->lock, flags);
dev->bbu = 0;
for (i = 1; i < 6; i++) {
dev->bbu += buf[i];
if (i != 5)
dev->bbu <<= 8;
}
dev_dbg(&dev->interface->dev, "%s count: %lld\n",
__func__, dev->bbu);
spin_unlock_irqrestore(&dev->lock, flags);
kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
}
else
dev_dbg(&dev->interface->dev,
"data format error - no EOF\n");
break;
case CMD_ACK:
dev_dbg(&dev->interface->dev, "%s ack: %c\n",
__func__, buf[1]);
wake_up_interruptible(&dev->waitq);
break;
}
exit:
retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
if (retval) {
dev_err(&dev->interface->dev, "%s - usb_submit_urb failed: %d\n",
__func__, retval);
}
}
static int yurex_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
struct usb_yurex *dev;
struct usb_host_interface *iface_desc;
struct usb_endpoint_descriptor *endpoint;
int retval = -ENOMEM;
DEFINE_WAIT(wait);
int res;
/* allocate memory for our device state and initialize it */
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
goto error;
kref_init(&dev->kref);
mutex_init(&dev->io_mutex);
spin_lock_init(&dev->lock);
init_waitqueue_head(&dev->waitq);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
dev->interface = interface;
/* set up the endpoint information */
iface_desc = interface->cur_altsetting;
res = usb_find_int_in_endpoint(iface_desc, &endpoint);
if (res) {
dev_err(&interface->dev, "Could not find endpoints\n");
retval = res;
goto error;
}
dev->int_in_endpointAddr = endpoint->bEndpointAddress;
/* allocate control URB */
dev->cntl_urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->cntl_urb)
goto error;
/* allocate buffer for control req */
dev->cntl_req = kmalloc(YUREX_BUF_SIZE, GFP_KERNEL);
if (!dev->cntl_req)
goto error;
/* allocate buffer for control msg */
dev->cntl_buffer = usb_alloc_coherent(dev->udev, YUREX_BUF_SIZE,
GFP_KERNEL,
&dev->cntl_urb->transfer_dma);
if (!dev->cntl_buffer) {
dev_err(&interface->dev, "Could not allocate cntl_buffer\n");
goto error;
}
/* configure control URB */
dev->cntl_req->bRequestType = USB_DIR_OUT | USB_TYPE_CLASS |
USB_RECIP_INTERFACE;
dev->cntl_req->bRequest = HID_REQ_SET_REPORT;
dev->cntl_req->wValue = cpu_to_le16((HID_OUTPUT_REPORT + 1) << 8);
dev->cntl_req->wIndex = cpu_to_le16(iface_desc->desc.bInterfaceNumber);
dev->cntl_req->wLength = cpu_to_le16(YUREX_BUF_SIZE);
usb_fill_control_urb(dev->cntl_urb, dev->udev,
usb_sndctrlpipe(dev->udev, 0),
(void *)dev->cntl_req, dev->cntl_buffer,
YUREX_BUF_SIZE, yurex_control_callback, dev);
dev->cntl_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
/* allocate interrupt URB */
dev->urb = usb_alloc_urb(0, GFP_KERNEL);
if (!dev->urb)
goto error;
/* allocate buffer for interrupt in */
dev->int_buffer = usb_alloc_coherent(dev->udev, YUREX_BUF_SIZE,
GFP_KERNEL, &dev->urb->transfer_dma);
if (!dev->int_buffer) {
dev_err(&interface->dev, "Could not allocate int_buffer\n");
goto error;
}
/* configure interrupt URB */
usb_fill_int_urb(dev->urb, dev->udev,
usb_rcvintpipe(dev->udev, dev->int_in_endpointAddr),
dev->int_buffer, YUREX_BUF_SIZE, yurex_interrupt,
dev, 1);
dev->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
if (usb_submit_urb(dev->urb, GFP_KERNEL)) {
retval = -EIO;
dev_err(&interface->dev, "Could not submitting URB\n");
goto error;
}
/* save our data pointer in this interface device */
usb_set_intfdata(interface, dev);
dev->bbu = -1;
/* we can register the device now, as it is ready */
retval = usb_register_dev(interface, &yurex_class);
if (retval) {
dev_err(&interface->dev,
"Not able to get a minor for this device.\n");
usb_set_intfdata(interface, NULL);
goto error;
}
dev_info(&interface->dev,
"USB YUREX device now attached to Yurex #%d\n",
interface->minor);
return 0;
error:
if (dev)
/* this frees allocated memory */
kref_put(&dev->kref, yurex_delete);
return retval;
}
static void yurex_disconnect(struct usb_interface *interface)
{
struct usb_yurex *dev;
int minor = interface->minor;
dev = usb_get_intfdata(interface);
usb_set_intfdata(interface, NULL);
/* give back our minor */
usb_deregister_dev(interface, &yurex_class);
/* prevent more I/O from starting */
mutex_lock(&dev->io_mutex);
dev->interface = NULL;
mutex_unlock(&dev->io_mutex);
/* wakeup waiters */
kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
wake_up_interruptible(&dev->waitq);
/* decrement our usage count */
kref_put(&dev->kref, yurex_delete);
dev_info(&interface->dev, "USB YUREX #%d now disconnected\n", minor);
}
static struct usb_driver yurex_driver = {
.name = "yurex",
.probe = yurex_probe,
.disconnect = yurex_disconnect,
.id_table = yurex_table,
};
static int yurex_fasync(int fd, struct file *file, int on)
{
struct usb_yurex *dev;
dev = file->private_data;
return fasync_helper(fd, file, on, &dev->async_queue);
}
static int yurex_open(struct inode *inode, struct file *file)
{
struct usb_yurex *dev;
struct usb_interface *interface;
int subminor;
int retval = 0;
subminor = iminor(inode);
interface = usb_find_interface(&yurex_driver, subminor);
if (!interface) {
printk(KERN_ERR "%s - error, can't find device for minor %d",
__func__, subminor);
retval = -ENODEV;
goto exit;
}
dev = usb_get_intfdata(interface);
if (!dev) {
retval = -ENODEV;
goto exit;
}
/* increment our usage count for the device */
kref_get(&dev->kref);
/* save our object in the file's private structure */
mutex_lock(&dev->io_mutex);
file->private_data = dev;
mutex_unlock(&dev->io_mutex);
exit:
return retval;
}
static int yurex_release(struct inode *inode, struct file *file)
{
struct usb_yurex *dev;
dev = file->private_data;
if (dev == NULL)
return -ENODEV;
/* decrement the count on our device */
kref_put(&dev->kref, yurex_delete);
return 0;
}
static ssize_t yurex_read(struct file *file, char __user *buffer, size_t count,
loff_t *ppos)
{
struct usb_yurex *dev;
int len = 0;
char in_buffer[20];
unsigned long flags;
dev = file->private_data;
mutex_lock(&dev->io_mutex);
if (!dev->interface) { /* already disconnected */
mutex_unlock(&dev->io_mutex);
return -ENODEV;
}
spin_lock_irqsave(&dev->lock, flags);
len = snprintf(in_buffer, 20, "%lld\n", dev->bbu);
spin_unlock_irqrestore(&dev->lock, flags);
mutex_unlock(&dev->io_mutex);
if (WARN_ON_ONCE(len >= sizeof(in_buffer)))
return -EIO;
return simple_read_from_buffer(buffer, count, ppos, in_buffer, len);
}
static ssize_t yurex_write(struct file *file, const char __user *user_buffer,
size_t count, loff_t *ppos)
{
struct usb_yurex *dev;
int i, set = 0, retval = 0;
char buffer[16 + 1];
char *data = buffer;
unsigned long long c, c2 = 0;
signed long timeout = 0;
DEFINE_WAIT(wait);
count = min(sizeof(buffer) - 1, count);
dev = file->private_data;
/* verify that we actually have some data to write */
if (count == 0)
goto error;
mutex_lock(&dev->io_mutex);
if (!dev->interface) { /* already disconnected */
mutex_unlock(&dev->io_mutex);
retval = -ENODEV;
goto error;
}
if (copy_from_user(buffer, user_buffer, count)) {
mutex_unlock(&dev->io_mutex);
retval = -EFAULT;
goto error;
}
buffer[count] = 0;
memset(dev->cntl_buffer, CMD_PADDING, YUREX_BUF_SIZE);
switch (buffer[0]) {
case CMD_ANIMATE:
case CMD_LED:
dev->cntl_buffer[0] = buffer[0];
dev->cntl_buffer[1] = buffer[1];
dev->cntl_buffer[2] = CMD_EOF;
break;
case CMD_READ:
case CMD_VERSION:
dev->cntl_buffer[0] = buffer[0];
dev->cntl_buffer[1] = 0x00;
dev->cntl_buffer[2] = CMD_EOF;
break;
case CMD_SET:
data++;
/* FALL THROUGH */
case '0' ... '9':
set = 1;
c = c2 = simple_strtoull(data, NULL, 0);
dev->cntl_buffer[0] = CMD_SET;
for (i = 1; i < 6; i++) {
dev->cntl_buffer[i] = (c>>32) & 0xff;
c <<= 8;
}
buffer[6] = CMD_EOF;
break;
default:
mutex_unlock(&dev->io_mutex);
return -EINVAL;
}
/* send the data as the control msg */
prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE);
dev_dbg(&dev->interface->dev, "%s - submit %c\n", __func__,
dev->cntl_buffer[0]);
retval = usb_submit_urb(dev->cntl_urb, GFP_KERNEL);
if (retval >= 0)
timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
finish_wait(&dev->waitq, &wait);
mutex_unlock(&dev->io_mutex);
if (retval < 0) {
dev_err(&dev->interface->dev,
"%s - failed to send bulk msg, error %d\n",
__func__, retval);
goto error;
}
if (set && timeout)
dev->bbu = c2;
return timeout ? count : -EIO;
error:
return retval;
}
static const struct file_operations yurex_fops = {
.owner = THIS_MODULE,
.read = yurex_read,
.write = yurex_write,
.open = yurex_open,
.release = yurex_release,
.fasync = yurex_fasync,
.llseek = default_llseek,
};
module_usb_driver(yurex_driver);
MODULE_LICENSE("GPL");