diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2012-10-03 16:25:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-31 10:10:00 -0700 |
| commit | 6f9445326d4a262a863cc634fd377c5ca562e17d (patch) | |
| tree | f76b65bfbf523719042551290e0fb7d456f77675 | |
| parent | 9f275003e609824e738b22caef0020d5c4a4def5 (diff) | |
staging: comedi: amplc_dio200: fix possible NULL deref during detach
commit dfb2540e91e1f63765bc3ff497ad0b714d774261 upstream.
`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.
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/amplc_dio200.c | 2 |
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 cc8931fde83..aee22fdd4e4 100644 --- a/drivers/staging/comedi/drivers/amplc_dio200.c +++ b/drivers/staging/comedi/drivers/amplc_dio200.c @@ -1429,6 +1429,8 @@ 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) { |