This is a note to let you know that I've just added the patch titled
staging: comedi: disallow COMEDI_DEVCONFIG on non-board minors
to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 754ab5c0e55dd118273ca2c217c4d95e9fbc8259 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbo...@mev.co.uk>
Date: Mon, 28 Jan 2013 16:14:31 +0000
Subject: staging: comedi: disallow COMEDI_DEVCONFIG on non-board minors
Comedi has two sorts of minor devices:
(a) normal board minor devices in the range 0 to
COMEDI_NUM_BOARD_MINORS-1 inclusive; and
(b) special subdevice minor devices in the range COMEDI_NUM_BOARD_MINORS
upwards that are used to open the same underlying comedi device as the
normal board minor devices, but with non-default read and write
subdevices for asynchronous commands.
The special subdevice minor devices get created when a board supporting
asynchronous commands is attached to a normal board minor device, and
destroyed when the board is detached from the normal board minor device.
One way to attach or detach a board is by using the COMEDI_DEVCONFIG
ioctl. This should only be used on normal board minors as the special
subdevice minors are too ephemeral. In particular, the change
introduced in commit 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c ("staging:
comedi: prevent auto-unconfig of manually configured devices") breaks
horribly for special subdevice minor devices.
Since there's no legitimate use for the COMEDI_DEVCONFIG ioctl on a
special subdevice minor device node, disallow it and return -ENOTTY.
Signed-off-by: Ian Abbott <abbo...@mev.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/comedi_fops.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/staging/comedi/comedi_fops.c
b/drivers/staging/comedi/comedi_fops.c
index fa534fe..38e4fcb 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1633,6 +1633,11 @@ static long comedi_unlocked_ioctl(struct file *file,
unsigned int cmd,
/* Device config is special, because it must work on
* an unconfigured device. */
if (cmd == COMEDI_DEVCONFIG) {
+ if (minor >= COMEDI_NUM_BOARD_MINORS) {
+ /* Device config not appropriate on non-board minors. */
+ rc = -ENOTTY;
+ goto done;
+ }
rc = do_devconfig_ioctl(dev,
(struct comedi_devconfig __user *)arg);
if (rc == 0)
--
1.8.1.336.g94702dd
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