From 3792dd12ee4419bc276cd321c8f74506a37aa93d Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 3 Oct 2012 16:25:19 +0100 Subject: [PATCH] staging: comedi: amplc_pc263: fix possible NULL deref during detach 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(+) diff --git a/drivers/staging/comedi/drivers/amplc_pc263.c b/drivers/staging/comedi/drivers/amplc_pc263.c index 8191c4e28e0a..8c0fbd1ceea5 100644 --- 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(struct comedi_device *dev, 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); -- 2.39.5