diff options
| author | James Hogan <james.hogan@imgtec.com> | 2011-09-20 15:23:46 +0200 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2011-09-20 15:23:46 +0200 |
| commit | 65b01bd561dc995aab116aa784f97a37f7c49a65 (patch) | |
| tree | cebcfb510b789147e185eba651d383d61c071ca9 | |
| parent | e4e436e0bd480668834fe6849a52c5397b7be4fb (diff) | |
HID: hidraw: protect hidraw_disconnect() better
The function hidraw_disconnect() only acquires the hidraw minors_lock
when clearing the entry in hidraw_table. However the device_destroy()
call can cause a userland read/write to return with an error. It may
cause the program to release the file descripter before the disconnect
is finished. hidraw_disconnect() has already set hidraw->exist to 0,
which makes hidraw_release() kfree the hidraw structure, which
hidraw_disconnect() continues to access and even tries to kfree again.
Similarly if a hidraw_release() occurs after setting hidraw->exist to 0,
the same thing can happen.
This is fixed by expanding the mutex critical section to cover the whole
function from setting hidraw->exist to 0 to freeing the hidraw
structure, preventing a hidraw_release() from interfering.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Tested-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| -rw-r--r-- | drivers/hid/hidraw.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index c79578b5a78..a8c2b7b6220 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -510,13 +510,12 @@ void hidraw_disconnect(struct hid_device *hid) { struct hidraw *hidraw = hid->hidraw; + mutex_lock(&minors_lock); hidraw->exist = 0; device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor)); - mutex_lock(&minors_lock); hidraw_table[hidraw->minor] = NULL; - mutex_unlock(&minors_lock); if (hidraw->open) { hid_hw_close(hid); @@ -524,6 +523,7 @@ void hidraw_disconnect(struct hid_device *hid) } else { kfree(hidraw); } + mutex_unlock(&minors_lock); } EXPORT_SYMBOL_GPL(hidraw_disconnect); |