| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 015/218] USB: cdc-acm: more sanity checking | Date | Thu, 31 Mar 2016 13:13:48 -0700 |
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4.2.8-ckt7 -stable 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: Kamal Mostafa <kamal@canonical.com> --- drivers/usb/class/cdc-acm.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index fa4e239..d37fdcc 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1114,6 +1114,9 @@ static int acm_probe(struct usb_interface *intf, 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; } -- 2.7.4
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