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authorIan Abbott <abbotti@mev.co.uk>2012-10-03 16:25:16 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-22 11:46:35 -0700
commitdfb2540e91e1f63765bc3ff497ad0b714d774261 (patch)
tree6c133023b675bd4a183fb3e1c4f62491195864c7 /drivers/staging/comedi
parentf4dd2367f3ad276fe49c89a522267ea5ccb6bf80 (diff)
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 <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/comedi')
-rw-r--r--drivers/staging/comedi/drivers/amplc_dio200.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/amplc_dio200.c b/drivers/staging/comedi/drivers/amplc_dio200.c
index 08f305210a69..29eb52d11d2f 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) {