5afeb104e7
usblcd currently has no way to limit memory consumption by fast writers. This is a security problem, as it allows users with write access to this device to drive the system into oom despite resource limits. Here's the fix taken from the modern skeleton driver. Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
413 lines
11 KiB
C
413 lines
11 KiB
C
/*****************************************************************************
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* USBLCD Kernel Driver *
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* Version 1.05 *
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* (C) 2005 Georges Toth <g.toth@e-biz.lu> *
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* *
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* This file is licensed under the GPL. See COPYING in the package. *
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* Based on usb-skeleton.c 2.0 by Greg Kroah-Hartman (greg@kroah.com) *
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* *
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* *
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* 28.02.05 Complete rewrite of the original usblcd.c driver, *
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* based on usb_skeleton.c. *
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* This new driver allows more than one USB-LCD to be connected *
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* and controlled, at once *
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*****************************************************************************/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <asm/uaccess.h>
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#include <linux/usb.h>
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#define DRIVER_VERSION "USBLCD Driver Version 1.05"
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#define USBLCD_MINOR 144
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#define IOCTL_GET_HARD_VERSION 1
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#define IOCTL_GET_DRV_VERSION 2
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static struct usb_device_id id_table [] = {
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{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
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{ },
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};
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MODULE_DEVICE_TABLE (usb, id_table);
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struct usb_lcd {
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struct usb_device * udev; /* init: probe_lcd */
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struct usb_interface * interface; /* the interface for this device */
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unsigned char * bulk_in_buffer; /* the buffer to receive data */
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size_t bulk_in_size; /* the size of the receive buffer */
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__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
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__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
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struct kref kref;
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struct semaphore limit_sem; /* to stop writes at full throttle from
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* using up all RAM */
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};
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#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
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#define USB_LCD_CONCURRENT_WRITES 5
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static struct usb_driver lcd_driver;
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static DEFINE_MUTEX(usb_lcd_open_mutex);
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static void lcd_delete(struct kref *kref)
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{
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struct usb_lcd *dev = to_lcd_dev(kref);
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usb_put_dev(dev->udev);
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kfree (dev->bulk_in_buffer);
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kfree (dev);
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}
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static int lcd_open(struct inode *inode, struct file *file)
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{
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struct usb_lcd *dev;
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struct usb_interface *interface;
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int subminor;
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int retval = 0;
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subminor = iminor(inode);
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mutex_lock(&usb_lcd_open_mutex);
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interface = usb_find_interface(&lcd_driver, subminor);
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if (!interface) {
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err ("USBLCD: %s - error, can't find device for minor %d",
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__FUNCTION__, subminor);
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retval = -ENODEV;
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goto exit;
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}
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dev = usb_get_intfdata(interface);
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if (!dev) {
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retval = -ENODEV;
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goto exit;
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}
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/* increment our usage count for the device */
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kref_get(&dev->kref);
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/* save our object in the file's private structure */
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file->private_data = dev;
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exit:
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mutex_unlock(&usb_lcd_open_mutex);
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return retval;
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}
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static int lcd_release(struct inode *inode, struct file *file)
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{
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struct usb_lcd *dev;
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dev = (struct usb_lcd *)file->private_data;
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if (dev == NULL)
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return -ENODEV;
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/* decrement the count on our device */
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kref_put(&dev->kref, lcd_delete);
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return 0;
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}
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static ssize_t lcd_read(struct file *file, char __user * buffer, size_t count, loff_t *ppos)
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{
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struct usb_lcd *dev;
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int retval = 0;
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int bytes_read;
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dev = (struct usb_lcd *)file->private_data;
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/* do a blocking bulk read to get data from the device */
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retval = usb_bulk_msg(dev->udev,
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usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
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dev->bulk_in_buffer,
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min(dev->bulk_in_size, count),
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&bytes_read, 10000);
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/* if the read was successful, copy the data to userspace */
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if (!retval) {
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if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
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retval = -EFAULT;
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else
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retval = bytes_read;
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}
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return retval;
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}
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static int lcd_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct usb_lcd *dev;
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u16 bcdDevice;
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char buf[30];
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dev = (struct usb_lcd *)file->private_data;
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if (dev == NULL)
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return -ENODEV;
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switch (cmd) {
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case IOCTL_GET_HARD_VERSION:
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bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
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sprintf(buf,"%1d%1d.%1d%1d",
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(bcdDevice & 0xF000)>>12,
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(bcdDevice & 0xF00)>>8,
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(bcdDevice & 0xF0)>>4,
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(bcdDevice & 0xF));
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if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
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return -EFAULT;
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break;
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case IOCTL_GET_DRV_VERSION:
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sprintf(buf,DRIVER_VERSION);
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if (copy_to_user((void __user *)arg,buf,strlen(buf))!=0)
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return -EFAULT;
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break;
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default:
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return -ENOTTY;
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break;
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}
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return 0;
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}
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static void lcd_write_bulk_callback(struct urb *urb)
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{
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struct usb_lcd *dev;
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dev = (struct usb_lcd *)urb->context;
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/* sync/async unlink faults aren't errors */
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if (urb->status &&
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!(urb->status == -ENOENT ||
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urb->status == -ECONNRESET ||
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urb->status == -ESHUTDOWN)) {
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dbg("USBLCD: %s - nonzero write bulk status received: %d",
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__FUNCTION__, urb->status);
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}
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/* free up our allocated buffer */
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usb_buffer_free(urb->dev, urb->transfer_buffer_length,
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urb->transfer_buffer, urb->transfer_dma);
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up(&dev->limit_sem);
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}
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static ssize_t lcd_write(struct file *file, const char __user * user_buffer, size_t count, loff_t *ppos)
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{
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struct usb_lcd *dev;
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int retval = 0, r;
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struct urb *urb = NULL;
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char *buf = NULL;
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dev = (struct usb_lcd *)file->private_data;
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/* verify that we actually have some data to write */
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if (count == 0)
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goto exit;
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r = down_interruptible(&dev->limit_sem);
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if (r < 0)
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return -EINTR;
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/* create a urb, and a buffer for it, and copy the data to the urb */
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urb = usb_alloc_urb(0, GFP_KERNEL);
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if (!urb) {
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retval = -ENOMEM;
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goto err_no_buf;
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}
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buf = usb_buffer_alloc(dev->udev, count, GFP_KERNEL, &urb->transfer_dma);
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if (!buf) {
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retval = -ENOMEM;
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goto error;
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}
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if (copy_from_user(buf, user_buffer, count)) {
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retval = -EFAULT;
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goto error;
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}
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/* initialize the urb properly */
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usb_fill_bulk_urb(urb, dev->udev,
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usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
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buf, count, lcd_write_bulk_callback, dev);
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urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
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/* send the data out the bulk port */
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retval = usb_submit_urb(urb, GFP_KERNEL);
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if (retval) {
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err("USBLCD: %s - failed submitting write urb, error %d", __FUNCTION__, retval);
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goto error;
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}
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/* release our reference to this urb, the USB core will eventually free it entirely */
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usb_free_urb(urb);
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exit:
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return count;
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error:
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usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
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usb_free_urb(urb);
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err_no_buf:
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up(&dev->limit_sem);
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return retval;
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}
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static const struct file_operations lcd_fops = {
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.owner = THIS_MODULE,
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.read = lcd_read,
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.write = lcd_write,
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.open = lcd_open,
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.ioctl = lcd_ioctl,
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.release = lcd_release,
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};
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/*
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* usb class driver info in order to get a minor number from the usb core,
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* and to have the device registered with the driver core
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*/
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static struct usb_class_driver lcd_class = {
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.name = "lcd%d",
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.fops = &lcd_fops,
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.minor_base = USBLCD_MINOR,
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};
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static int lcd_probe(struct usb_interface *interface, const struct usb_device_id *id)
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{
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struct usb_lcd *dev = NULL;
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struct usb_host_interface *iface_desc;
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struct usb_endpoint_descriptor *endpoint;
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size_t buffer_size;
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int i;
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int retval = -ENOMEM;
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/* allocate memory for our device state and initialize it */
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (dev == NULL) {
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err("Out of memory");
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goto error;
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}
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kref_init(&dev->kref);
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sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
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dev->udev = usb_get_dev(interface_to_usbdev(interface));
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dev->interface = interface;
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if (le16_to_cpu(dev->udev->descriptor.idProduct) != 0x0001) {
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warn(KERN_INFO "USBLCD model not supported.");
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return -ENODEV;
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}
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/* set up the endpoint information */
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/* use only the first bulk-in and bulk-out endpoints */
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iface_desc = interface->cur_altsetting;
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for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
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endpoint = &iface_desc->endpoint[i].desc;
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if (!dev->bulk_in_endpointAddr &&
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usb_endpoint_is_bulk_in(endpoint)) {
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/* we found a bulk in endpoint */
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buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
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dev->bulk_in_size = buffer_size;
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dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
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dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
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if (!dev->bulk_in_buffer) {
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err("Could not allocate bulk_in_buffer");
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goto error;
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}
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}
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if (!dev->bulk_out_endpointAddr &&
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usb_endpoint_is_bulk_out(endpoint)) {
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/* we found a bulk out endpoint */
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dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
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}
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}
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if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
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err("Could not find both bulk-in and bulk-out endpoints");
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goto error;
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}
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/* save our data pointer in this interface device */
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usb_set_intfdata(interface, dev);
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/* we can register the device now, as it is ready */
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retval = usb_register_dev(interface, &lcd_class);
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if (retval) {
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/* something prevented us from registering this driver */
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err("Not able to get a minor for this device.");
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usb_set_intfdata(interface, NULL);
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goto error;
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}
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i = le16_to_cpu(dev->udev->descriptor.bcdDevice);
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info("USBLCD Version %1d%1d.%1d%1d found at address %d",
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(i & 0xF000)>>12,(i & 0xF00)>>8,(i & 0xF0)>>4,(i & 0xF),
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dev->udev->devnum);
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/* let the user know what node this device is now attached to */
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info("USB LCD device now attached to USBLCD-%d", interface->minor);
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return 0;
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error:
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if (dev)
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kref_put(&dev->kref, lcd_delete);
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return retval;
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}
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static void lcd_disconnect(struct usb_interface *interface)
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{
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struct usb_lcd *dev;
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int minor = interface->minor;
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/* prevent skel_open() from racing skel_disconnect() */
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mutex_lock(&usb_lcd_open_mutex);
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dev = usb_get_intfdata(interface);
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usb_set_intfdata(interface, NULL);
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/* give back our minor */
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usb_deregister_dev(interface, &lcd_class);
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mutex_unlock(&usb_lcd_open_mutex);
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/* decrement our usage count */
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kref_put(&dev->kref, lcd_delete);
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info("USB LCD #%d now disconnected", minor);
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}
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static struct usb_driver lcd_driver = {
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.name = "usblcd",
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.probe = lcd_probe,
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.disconnect = lcd_disconnect,
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.id_table = id_table,
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};
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static int __init usb_lcd_init(void)
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{
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int result;
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result = usb_register(&lcd_driver);
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if (result)
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err("usb_register failed. Error number %d", result);
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return result;
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}
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static void __exit usb_lcd_exit(void)
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{
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usb_deregister(&lcd_driver);
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}
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module_init(usb_lcd_init);
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module_exit(usb_lcd_exit);
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MODULE_AUTHOR("Georges Toth <g.toth@e-biz.lu>");
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MODULE_DESCRIPTION(DRIVER_VERSION);
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MODULE_LICENSE("GPL");
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