From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Ian Abbott Subject: [ 032/101] staging: comedi: amplc_pc263: fix possible NULL deref during detach Date: Mon, 29 Oct 2012 14:34:45 -0700 Message-Id: <20121029213243.787014490@linuxfoundation.org> In-Reply-To: <20121029213240.128426598@linuxfoundation.org> References: <20121029213240.128426598@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 1d1171ffda585c1cab7bd7cf4bd8f8fd5923fb4a upstream. `pc263_detach()` is called by the comedi core to clean up if either `pc263_attach()` or `pc263_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 `pc263_attach()` fails, but not if `pc263_attach_pci()` fails, leading to a possible NULL pointer dereference. Check `thisboard` at the top of `pc263_detach()` and return early if it is `NULL`. This is okay because no other resources need cleaning up in this case. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/amplc_pc263.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/staging/comedi/drivers/amplc_pc263.c +++ b/drivers/staging/comedi/drivers/amplc_pc263.c @@ -310,8 +310,11 @@ static int __devinit pc263_attach_pci(st static void pc263_detach(struct comedi_device *dev) { + const struct pc263_board *thisboard = comedi_board(dev); struct pci_dev *pcidev = comedi_to_pci_dev(dev); + if (!thisboard) + return; if (pcidev) { if (dev->iobase) comedi_pci_disable(pcidev);