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USB: adutux: fix NULL-derefs on disconnect 

The driver was using its struct usb_device 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 statements in the completion handlers
which relies on said pointer.

The pointer was also dereferenced unconditionally in a dev_dbg statement
release() something which would lead to a NULL-deref whenever a device
was disconnected before the final character-device close if debugging
was enabled.

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: 1ef37c6047 ("USB: adutux: remove custom debug macro and module parameter")
Fixes: 66d4bc30d1 ("USB: adutux: remove custom debug macro")
Cc: stable <stable@vger.kernel.org>     # 3.12
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20190925092913.8608-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2019-09-25 11:29:13 +02:00 committed by Greg Kroah-Hartman
parent 44efc269db
commit b2fa7baee7
1 changed files with 10 additions and 6 deletions
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16
drivers/usb/misc/adutux.c
View File

@ -75,6 +75,7 @@ struct adu_device {
char serial_number[8];
int open_count; /* number of times this port has been opened */
unsigned long disconnected:1;
char *read_buffer_primary;
int read_buffer_length;
@ -116,7 +117,7 @@ static void adu_abort_transfers(struct adu_device *dev)
{
unsigned long flags;
if (dev->udev == NULL)
if (dev->disconnected)
return;
/* shutdown transfer */
@ -243,7 +244,7 @@ static int adu_open(struct inode *inode, struct file *file)
}
dev = usb_get_intfdata(interface);
if (!dev || !dev->udev) {
if (!dev) {
retval = -ENODEV;
goto exit_no_device;
}
@ -326,7 +327,7 @@ static int adu_release(struct inode *inode, struct file *file)
}
adu_release_internal(dev);
if (dev->udev == NULL) {
if (dev->disconnected) {
/* the device was unplugged before the file was released */
if (!dev->open_count) /* ... and we're the last user */
adu_delete(dev);
@ -354,7 +355,7 @@ static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
return -ERESTARTSYS;
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto exit;
@ -518,7 +519,7 @@ static ssize_t adu_write(struct file *file, const __user char *buffer,
goto exit_nolock;
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto exit;
@ -764,11 +765,14 @@ static void adu_disconnect(struct usb_interface *interface)
usb_deregister_dev(interface, &adu_class);
usb_poison_urb(dev->interrupt_in_urb);
usb_poison_urb(dev->interrupt_out_urb);
mutex_lock(&adutux_mutex);
usb_set_intfdata(interface, NULL);
mutex_lock(&dev->mtx); /* not interruptible */
dev->udev = NULL; /* poison */
dev->disconnected = 1;
mutex_unlock(&dev->mtx);
/* if the device is not opened, then we clean up right now */