From: Ian Abbott <abbotti@mev.co.uk>
Date: Wed, 3 Oct 2012 15:25:18 +0000 (+0100)
Subject: staging: comedi: amplc_pc236: fix possible NULL deref during detach
X-Git-Tag: v3.7-rc3~13^2~15
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2db012bd40b889d8e5483d3daa07af04c4c109d8;p=pandora-kernel.git

staging: comedi: amplc_pc236: fix possible NULL deref during detach

`pc236_detach()` is called by the comedi core to clean up if either
`pc236_attach()` or `pc236_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 `pc236_attach()` fails, but not
if `pc236_attach_pci()` fails, leading to a possible NULL pointer
dereference.

Check `thisboard` at the top of `pc236_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>
---

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