diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2012-10-03 16:25:18 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-31 10:10:00 -0700 |
| commit | 6c04efd97dd25596a1bf80cc1c518fe7e451cc1e (patch) | |
| tree | ec6e7d3767851e372afbe391be7c17f567609dbf | |
| parent | ec7fe3d6e91ff29ee3000e35f13f5eb3df2eca30 (diff) | |
staging: comedi: amplc_pc236: fix possible NULL deref during detach
commit 2db012bd40b889d8e5483d3daa07af04c4c109d8 upstream.
`pc236_detach()` is called by the comedi core to clean up if either
`pc236_attach()` or `pc236_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 `pc236_attach()` fails, but not
if `pc236_attach_pci()` fails, leading to a possible NULL pointer
dereference.
Check `thisboard` at the top of `pc236_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_pc236.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c index cfbb83b9526..b46e66310d7 100644 --- a/drivers/staging/comedi/drivers/amplc_pc236.c +++ b/drivers/staging/comedi/drivers/amplc_pc236.c @@ -577,8 +577,11 @@ static int __devinit pc236_attach_pci(struct comedi_device *dev, static void pc236_detach(struct comedi_device *dev) { + const struct pc236_board *thisboard = comedi_board(dev); struct pci_dev *pcidev = comedi_to_pci_dev(dev); + if (!thisboard) + return; if (dev->iobase) pc236_intr_disable(dev); if (dev->irq) |