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| author | Ian Abbott <abbotti@mev.co.uk> | 2012-10-03 16:25:21 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-22 11:46:35 -0700 |
| commit | 922b67c1ac53014d80649a961a2fde700cd065d8 (patch) | |
| tree | b4147117c01bd28f4425f6fb0d0e67b1a99bed3f /drivers/staging | |
| parent | ee280d134f2e05e0172369a53fbe202dbfc527fa (diff) | |
| download | lwn-922b67c1ac53014d80649a961a2fde700cd065d8.tar.gz lwn-922b67c1ac53014d80649a961a2fde700cd065d8.zip | |
staging: comedi: ni_labpc: fix possible NULL deref during detach
`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.
Cc: <stable@vger.kernel.org> # 3.6.x
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -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 28b91a6c3789..b5a19a0863fb 100644 --- a/drivers/staging/comedi/drivers/ni_labpc.c +++ b/drivers/staging/comedi/drivers/ni_labpc.c @@ -772,6 +772,8 @@ void labpc_common_detach(struct comedi_device *dev) { struct comedi_subdevice *s; + if (!thisboard) + return; if (dev->subdevices) { s = &dev->subdevices[2]; subdev_8255_cleanup(dev, s); |