diff options
author | Johan Hovold <johan@kernel.org> | 2019-10-09 17:38:46 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-10 12:43:18 +0200 |
commit | 58ecf131e74620305175a7aa103f81350bb37570 (patch) | |
tree | a290f2aa14bd66ab3a87b01d5fbf05582eca747d /drivers/usb | |
parent | 726b55d0e22ca72c69c947af87785c830289ddbc (diff) | |
download | linux-58ecf131e74620305175a7aa103f81350bb37570.tar.bz2 |
USB: ldusb: fix NULL-derefs on driver unbind
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>
Diffstat (limited to 'drivers/usb')
-rw-r--r-- | drivers/usb/misc/ldusb.c | 24 |
1 files changed, 12 insertions, 12 deletions
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); |