diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2012-10-03 16:25:21 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-31 10:09:59 -0700 |
| commit | 9f275003e609824e738b22caef0020d5c4a4def5 (patch) | |
| tree | f6cff1a37dea1a4e8085d05bf936ffbc6239bd4d | |
| parent | 8098a2e23e88e979566c78e68aec11fa21808df0 (diff) | |
staging: comedi: ni_labpc: fix possible NULL deref during detach
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>
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_labpc.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c index ab8b787c78b..d3a1d65fd63 100644 --- 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 comedi_device *dev, int bus, int slot) 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 |