From 7f77897ef2b6a5ee4eb8bc24fe8b1f3eab254328 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina@suse.cz>
Date: Tue, 24 May 2011 11:43:18 +0200
Subject: [PATCH] HID: hiddev: fix potential use-after-free
Commit 6cb4b040795 ("HID: hiddev: fix race between hiddev_disconnect
and hiddev_release") made it possible to access hiddev (for unlocking
the existance mutex) once hiddev has been kfreed.
Change the order so that this can not happen (always unlock the mutex first,
it is needed only to protect access to ->exist and ->open).
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
drivers/hid/usbhid/hiddev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index ff3c644888b1..4985f485932f 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -923,10 +923,11 @@ void hiddev_disconnect(struct hid_device *hid)
usb_deregister_dev(usbhid->intf, &hiddev_class);
if (hiddev->open) {
+ mutex_unlock(&hiddev->existancelock);
usbhid_close(hiddev->hid);
wake_up_interruptible(&hiddev->wait);
} else {
+ mutex_unlock(&hiddev->existancelock);
kfree(hiddev);
}
- mutex_unlock(&hiddev->existancelock);
}
--
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