From 8568ed230b9cf849a6a0305173d5ce059aa55343 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 25 Sep 2019 11:29:12 +0200 Subject: [PATCH] USB: adutux: fix use-after-free on disconnect BugLink: https://bugs.launchpad.net/bugs/1850541 commit 44efc269db7929f6275a1fa927ef082e533ecde0 upstream. 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 # 2.6.24 Reported-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com Tested-by: syzbot+0243cb250a51eeefb8cc@syzkaller.appspotmail.com Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20190925092913.8608-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Kleber Sacilotto de Souza --- 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 4b8712733fc7..3a88a1159c8f 100644 --- a/drivers/usb/misc/adutux.c +++ b/drivers/usb/misc/adutux.c @@ -760,14 +760,15 @@ 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); -- 2.39.2