| From | Ben Hutchings <> | Date | Wed, 27 Apr 2016 01:02:24 +0200 | Subject | [PATCH 3.2 046/115] USB: cdc-acm: more sanity checking |
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3.2.80-rc1 review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum <oneukum@suse.com>
commit 8835ba4a39cf53f705417b3b3a94eb067673f2c9 upstream.
An attack has become available which pretends to be a quirky device circumventing normal sanity checks and crashes the kernel by an insufficient number of interfaces. This patch adds a check to the code path for quirky devices.
Signed-off-by: Oliver Neukum <ONeukum@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/usb/class/cdc-acm.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -926,6 +926,9 @@ static int acm_probe(struct usb_interfac if (quirks == NO_UNION_NORMAL) { data_interface = usb_ifnum_to_if(usb_dev, 1); control_interface = usb_ifnum_to_if(usb_dev, 0); + /* we would crash */ + if (!data_interface || !control_interface) + return -ENODEV; goto skip_normal_probe; }
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