diff options
| author | Johan Hovold <johan@kernel.org> | 2019-10-09 13:48:41 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-10 13:45:06 +0300 |
| commit | edc4746f253d907d048de680a621e121517f484b (patch) | |
| tree | f4673df04042dbfe69fd47d8b12e72fbd482dfe6 /drivers | |
| parent | 93ddb1f56ae102f14f9e46a9a9c8017faa970003 (diff) | |
| download | linux-edc4746f253d907d048de680a621e121517f484b.tar.xz | |
USB: iowarrior: fix use-after-free on disconnect
A recent fix addressing a deadlock on disconnect introduced a new bug
by moving the present flag out of the critical section protected by the
driver-data mutex. This could lead to a racing release() freeing the
driver data before disconnect() is done with it.
Due to insufficient locking a related use-after-free could be triggered
also before the above mentioned commit. Specifically, the driver needs
to hold the driver-data mutex also while checking the opened flag at
disconnect().
Fixes: c468a8aa790e ("usb: iowarrior: fix deadlock on disconnect")
Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.")
Cc: stable <stable@vger.kernel.org> # 2.6.21
Reported-by: syzbot+0761012cebf7bdb38137@syzkaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009104846.5925-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/misc/iowarrior.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c index f5bed9f29e56..4fe1d3267b3c 100644 --- a/drivers/usb/misc/iowarrior.c +++ b/drivers/usb/misc/iowarrior.c @@ -866,8 +866,6 @@ static void iowarrior_disconnect(struct usb_interface *interface) dev = usb_get_intfdata(interface); mutex_lock(&iowarrior_open_disc_lock); usb_set_intfdata(interface, NULL); - /* prevent device read, write and ioctl */ - dev->present = 0; minor = dev->minor; mutex_unlock(&iowarrior_open_disc_lock); @@ -878,8 +876,7 @@ static void iowarrior_disconnect(struct usb_interface *interface) mutex_lock(&dev->mutex); /* prevent device read, write and ioctl */ - - mutex_unlock(&dev->mutex); + dev->present = 0; if (dev->opened) { /* There is a process that holds a filedescriptor to the device , @@ -889,8 +886,10 @@ static void iowarrior_disconnect(struct usb_interface *interface) usb_kill_urb(dev->int_in_urb); wake_up_interruptible(&dev->read_wait); wake_up_interruptible(&dev->write_wait); + mutex_unlock(&dev->mutex); } else { /* no process is using the device, cleanup now */ + mutex_unlock(&dev->mutex); iowarrior_delete(dev); } |