This is a note to let you know that I've just added the patch titled
USB: adutux: fix use-after-free on disconnect
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 44efc269db7929f6275a1fa927ef082e533ecde0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Wed, 25 Sep 2019 11:29:12 +0200
Subject: 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@xxxxxxxxxxxxxxx> # 2.6.24
Reported-by: syzbot+0243cb250a51eeefb8cc@xxxxxxxxxxxxxxxxxxxxxxxxx
Tested-by: syzbot+0243cb250a51eeefb8cc@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20190925092913.8608-1-johan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/misc/adutux.c | 7 ++++---
1 file 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);
--
2.23.0
