diff options
| author | Johan Hovold <johan@kernel.org> | 2019-10-09 12:48:41 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-17 13:43:26 -0700 |
| commit | 10b0e388a18353d224ccf17cc46a57f1070abb2b (patch) | |
| tree | 682d6aac35711f6d2ba9849c327a31a0dc7bed3d /drivers/usb | |
| parent | b04c5f3fb80f7c6c963ac0a80a4832d25a84d1ca (diff) | |
USB: iowarrior: fix use-after-free on disconnect
commit edc4746f253d907d048de680a621e121517f484b upstream.
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/usb')
| -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 43bee6dad5c9..2f4c2282939d 100644 --- a/drivers/usb/misc/iowarrior.c +++ b/drivers/usb/misc/iowarrior.c @@ -870,8 +870,6 @@ 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); @@ -882,8 +880,7 @@ 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 , @@ -893,8 +890,10 @@ 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); } |