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| author | Johan Hovold <johan@kernel.org> | 2019-09-25 11:29:12 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-04 11:02:59 +0200 |
| commit | 44efc269db7929f6275a1fa927ef082e533ecde0 (patch) | |
| tree | 2b3af409defcaf291d96984a62a58f6d51e6aa7a | |
| parent | 9816144313d33974bbd4599d4e8e554c11cae27e (diff) | |
| download | lwn-44efc269db7929f6275a1fa927ef082e533ecde0.tar.gz lwn-44efc269db7929f6275a1fa927ef082e533ecde0.zip | |
USB: adutux: fix use-after-free on disconnect
The driver was clearing its struct usb_device pointer, which it used as
an inverted disconnected flag, before deregistering the character device
and without serialising against racing release().
This could lead to a use-after-free if a racing release() callback
observes the cleared pointer and frees the driver data before
disconnect() is finished with it.
This could also lead to NULL-pointer dereferences in a racing open().
Fixes: f08812d5eb8f ("USB: FIx locks and urb->status in adutux (updated)")
Cc: stable <stable@vger.kernel.org> # 2.6.24
Reported-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com
Tested-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20190925092913.8608-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/misc/adutux.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c index 344d523b0502..bcc138990e2f 100644 --- a/drivers/usb/misc/adutux.c +++ b/drivers/usb/misc/adutux.c @@ -762,14 +762,15 @@ static void adu_disconnect(struct usb_interface *interface) dev = usb_get_intfdata(interface); - mutex_lock(&dev->mtx); /* not interruptible */ - dev->udev = NULL; /* poison */ usb_deregister_dev(interface, &adu_class); - mutex_unlock(&dev->mtx); mutex_lock(&adutux_mutex); usb_set_intfdata(interface, NULL); + mutex_lock(&dev->mtx); /* not interruptible */ + dev->udev = NULL; /* poison */ + mutex_unlock(&dev->mtx); + /* if the device is not opened, then we clean up right now */ if (!dev->open_count) adu_delete(dev); |