Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 030/101] staging: comedi: ni_labpc: fix possible NULL deref during detach | Date | Mon, 29 Oct 2012 14:34:43 -0700 |
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3.6-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott <abbotti@mev.co.uk>
commit 922b67c1ac53014d80649a961a2fde700cd065d8 upstream.
`labpc_common_detach()` is called by the comedi core to clean up if either `labpc_attach()` (including the one in the "ni_labpc_cs" module) or `labpc_attach_pci()` returns an error. It assumes the `thisboard` macro (expanding to `((struct labpc_board_struct *)dev->board_ptr)`) is non-null. This is a valid assumption if `labpc_attach()` fails, but not if `labpc_attach_pci()` fails, leading to a possible NULL pointer dereference.
Check `thisboard` at the top of `labpc_common_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.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/staging/comedi/drivers/ni_labpc.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/staging/comedi/drivers/ni_labpc.c +++ b/drivers/staging/comedi/drivers/ni_labpc.c @@ -809,6 +809,8 @@ static int labpc_find_device(struct come void labpc_common_detach(struct comedi_device *dev) { + if (!thisboard) + return; if (dev->subdevices) subdev_8255_cleanup(dev, dev->subdevices + 2); #ifdef CONFIG_ISA_DMA_API
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