| From 6f28b4041054790c24c68a6014f4d869619f6deb Mon Sep 17 00:00:00 2001 |
| From: Johan Hovold <johan@kernel.org> |
| Date: Wed, 9 Oct 2019 17:38:46 +0200 |
| Subject: [PATCH] USB: ldusb: fix NULL-derefs on driver unbind |
| |
| commit 58ecf131e74620305175a7aa103f81350bb37570 upstream. |
| |
| The driver was using its struct usb_interface pointer as an inverted |
| disconnected flag, but was setting it to NULL before making sure all |
| completion handlers had run. This could lead to a NULL-pointer |
| dereference in a number of dev_dbg, dev_warn and dev_err statements in |
| the completion handlers which relies on said pointer. |
| |
| Fix this by unconditionally stopping all I/O and preventing |
| resubmissions by poisoning the interrupt URBs at disconnect and using a |
| dedicated disconnected flag. |
| |
| This also makes sure that all I/O has completed by the time the |
| disconnect callback returns. |
| |
| Fixes: 2824bd250f0b ("[PATCH] USB: add ldusb driver") |
| Cc: stable <stable@vger.kernel.org> # 2.6.13 |
| Signed-off-by: Johan Hovold <johan@kernel.org> |
| Link: https://lore.kernel.org/r/20191009153848.8664-4-johan@kernel.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/usb/misc/ldusb.c b/drivers/usb/misc/ldusb.c |
| index 6581774bdfa4..f3108d85e768 100644 |
| --- a/drivers/usb/misc/ldusb.c |
| +++ b/drivers/usb/misc/ldusb.c |
| @@ -153,6 +153,7 @@ MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in |
| struct ld_usb { |
| struct mutex mutex; /* locks this structure */ |
| struct usb_interface *intf; /* save off the usb interface pointer */ |
| + unsigned long disconnected:1; |
| |
| int open_count; /* number of times this port has been opened */ |
| |
| @@ -192,12 +193,10 @@ static void ld_usb_abort_transfers(struct ld_usb *dev) |
| /* shutdown transfer */ |
| if (dev->interrupt_in_running) { |
| dev->interrupt_in_running = 0; |
| - if (dev->intf) |
| - usb_kill_urb(dev->interrupt_in_urb); |
| + usb_kill_urb(dev->interrupt_in_urb); |
| } |
| if (dev->interrupt_out_busy) |
| - if (dev->intf) |
| - usb_kill_urb(dev->interrupt_out_urb); |
| + usb_kill_urb(dev->interrupt_out_urb); |
| } |
| |
| /** |
| @@ -205,8 +204,6 @@ static void ld_usb_abort_transfers(struct ld_usb *dev) |
| */ |
| static void ld_usb_delete(struct ld_usb *dev) |
| { |
| - ld_usb_abort_transfers(dev); |
| - |
| /* free data structures */ |
| usb_free_urb(dev->interrupt_in_urb); |
| usb_free_urb(dev->interrupt_out_urb); |
| @@ -263,7 +260,7 @@ static void ld_usb_interrupt_in_callback(struct urb *urb) |
| |
| resubmit: |
| /* resubmit if we're still running */ |
| - if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) { |
| + if (dev->interrupt_in_running && !dev->buffer_overflow) { |
| retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC); |
| if (retval) { |
| dev_err(&dev->intf->dev, |
| @@ -392,7 +389,7 @@ static int ld_usb_release(struct inode *inode, struct file *file) |
| retval = -ENODEV; |
| goto unlock_exit; |
| } |
| - if (dev->intf == NULL) { |
| + if (dev->disconnected) { |
| /* the device was unplugged before the file was released */ |
| mutex_unlock(&dev->mutex); |
| /* unlock here as ld_usb_delete frees dev */ |
| @@ -423,7 +420,7 @@ static __poll_t ld_usb_poll(struct file *file, poll_table *wait) |
| |
| dev = file->private_data; |
| |
| - if (!dev->intf) |
| + if (dev->disconnected) |
| return EPOLLERR | EPOLLHUP; |
| |
| poll_wait(file, &dev->read_wait, wait); |
| @@ -462,7 +459,7 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count, |
| } |
| |
| /* verify that the device wasn't unplugged */ |
| - if (dev->intf == NULL) { |
| + if (dev->disconnected) { |
| retval = -ENODEV; |
| printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval); |
| goto unlock_exit; |
| @@ -542,7 +539,7 @@ static ssize_t ld_usb_write(struct file *file, const char __user *buffer, |
| } |
| |
| /* verify that the device wasn't unplugged */ |
| - if (dev->intf == NULL) { |
| + if (dev->disconnected) { |
| retval = -ENODEV; |
| printk(KERN_ERR "ldusb: No device or device unplugged %d\n", retval); |
| goto unlock_exit; |
| @@ -764,6 +761,9 @@ static void ld_usb_disconnect(struct usb_interface *intf) |
| /* give back our minor */ |
| usb_deregister_dev(intf, &ld_usb_class); |
| |
| + usb_poison_urb(dev->interrupt_in_urb); |
| + usb_poison_urb(dev->interrupt_out_urb); |
| + |
| mutex_lock(&dev->mutex); |
| |
| /* if the device is not opened, then we clean up right now */ |
| @@ -771,7 +771,7 @@ static void ld_usb_disconnect(struct usb_interface *intf) |
| mutex_unlock(&dev->mutex); |
| ld_usb_delete(dev); |
| } else { |
| - dev->intf = NULL; |
| + dev->disconnected = 1; |
| /* wake up pollers */ |
| wake_up_interruptible_all(&dev->read_wait); |
| wake_up_interruptible_all(&dev->write_wait); |
| -- |
| 2.7.4 |
| |