tree 5f2056a8137a341ad42e17d0f44657ee6c8fa2de
parent 1d1171ffda585c1cab7bd7cf4bd8f8fd5923fb4a
author Ian Abbott <abbotti@mev.co.uk> 1349277920 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1350931595 -0700

staging: comedi: das08: fix possible NULL deref during detach

`das08_detach()` is called by the comedi core to clean up if either
`das08_attach()` or `das08_attach_pci()` returns an error.  It sets
`thisboard` to the return value of `comedi_board(dev)` and assumes it is
non-null.  This is a valid assumption if `das08_attach()` fails, but not
if `das08_attach_pci()` fails, leading to a possible NULL pointer
dereference.

Check `thisboard` at the top of `das08_detach()` and return early if it
is `NULL`.  This is okay because the only other thing that could have
been allocated is `dev->private` and that is freed by the comedi core,
not by this function.

Cc: <stable@vger.kernel.org> # 3.6.x
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>