From: Ian Abbott Date: Wed, 3 Oct 2012 15:25:19 +0000 (+0100) Subject: staging: comedi: amplc_pc263: fix possible NULL deref during detach X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1d1171ffda585c1cab7bd7cf4bd8f8fd5923fb4a;p=linux-beck.git staging: comedi: amplc_pc263: fix possible NULL deref during detach `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. Cc: # 3.6.x Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/amplc_pc263.c b/drivers/staging/comedi/drivers/amplc_pc263.c index 60830ccfb903..d0a4c441228b 100644 --- a/drivers/staging/comedi/drivers/amplc_pc263.c +++ b/drivers/staging/comedi/drivers/amplc_pc263.c @@ -323,6 +323,8 @@ static void pc263_detach(struct comedi_device *dev) { const struct pc263_board *thisboard = comedi_board(dev); + if (!thisboard) + return; if (is_isa_board(thisboard)) { if (dev->iobase) release_region(dev->iobase, PC263_IO_SIZE);