`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@xxxxxxxxxxxxxxx> # 3.6.x
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/das08.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/comedi/drivers/das08.c b/drivers/staging/comedi/drivers/das08.c
index 5fd21fa..c304528 100644
--- a/drivers/staging/comedi/drivers/das08.c
+++ b/drivers/staging/comedi/drivers/das08.c
@@ -846,6 +846,8 @@ static void __maybe_unused das08_detach(struct comedi_device *dev)
{
const struct das08_board_struct *thisboard = comedi_board(dev);
+ if (!thisboard)
+ return;
das08_common_detach(dev);
if (is_isa_board(thisboard)) {
if (dev->iobase)
--
1.7.12
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