This is a note to let you know that I've just added the patch titled
staging: comedi: amplc_dio200: fix possible NULL deref during detach
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From dfb2540e91e1f63765bc3ff497ad0b714d774261 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbo...@mev.co.uk>
Date: Wed, 3 Oct 2012 16:25:16 +0100
Subject: staging: comedi: amplc_dio200: fix possible NULL deref during detach
`dio200_detach()` is called by the comedi core to clean up if either
`dio200_attach()` or `dio200_attach_pci()` return an error. It assigns
`thisboard` to the return value of `comedi_board(dev)` and assumes it is
non-null. In the case of a previous call to `dio200_attach()` it won't
be `NULL` because the comedi core will have pointed it to one of the
elements of `dio200_boards[]`, but in the case of a previous call to
`dio200_attach_pci()` it could be `NULL`, leading to a null pointer
dereference.
Check that `thisboard` is valid at the top of `dio200_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 <abbo...@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/amplc_dio200.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/comedi/drivers/amplc_dio200.c
b/drivers/staging/comedi/drivers/amplc_dio200.c
index 08f3052..29eb52d 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200.c
@@ -1410,6 +1410,8 @@ static void dio200_detach(struct comedi_device *dev)
const struct dio200_layout_struct *layout;
unsigned n;
+ if (!thisboard)
+ return;
if (dev->irq)
free_irq(dev->irq, dev);
if (dev->subdevices) {
--
1.7.12.2.421.g261b511
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