linux-kernel - [ 028/101] staging: comedi: das08: fix possible NULL deref during detach

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 29 Oct 2012 14:34:41 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	alan@...rguk.ukuu.org.uk, Ian Abbott <abbotti@....co.uk>
Subject: [ 028/101] staging: comedi: das08: fix possible NULL deref during detach

3.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ian Abbott <abbotti@....co.uk>

commit ee280d134f2e05e0172369a53fbe202dbfc527fa upstream.

`das08_detach()` is called by the comedi core to clean up if either
`das08_attach()` or `das08_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 `das08_attach()` fails, but not
if `das08_attach_pci()` fails, leading to a possible NULL pointer
dereference.

Check `thisboard` at the top of `das08_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@....co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/staging/comedi/drivers/das08.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/staging/comedi/drivers/das08.c
+++ b/drivers/staging/comedi/drivers/das08.c
@@ -1028,6 +1028,8 @@ static void __maybe_unused das08_detach(
 	const struct das08_board_struct *thisboard = comedi_board(dev);
 	struct das08_private_struct *devpriv = dev->private;

+	if (!thisboard)
+		return;
 	das08_common_detach(dev);
 	if (IS_ENABLED(CONFIG_COMEDI_DAS08_ISA) &&
 	    (thisboard->bustype == isa || thisboard->bustype == pc104)) {

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/