diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 20 | ||||
| -rw-r--r-- | Documentation/usb/authorization.txt | 31 |
2 files changed, 51 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 864637f25bee..3a4abfc44f5e 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -1,3 +1,23 @@ +What: /sys/bus/usb/devices/INTERFACE/authorized +Date: August 2015 +Description: + This allows to authorize (1) or deauthorize (0) + individual interfaces instead a whole device + in contrast to the device authorization. + If a deauthorized interface will be authorized + so the driver probing must be triggered manually + by writing INTERFACE to /sys/bus/usb/drivers_probe + This allows to avoid side-effects with drivers + that need multiple interfaces. + A deauthorized interface cannot be probed or claimed. + +What: /sys/bus/usb/devices/usbX/interface_authorized_default +Date: August 2015 +Description: + This is used as value that determines if interfaces + would be authorized by default. + The value can be 1 or 0. It's by default 1. + What: /sys/bus/usb/device/.../authorized Date: July 2008 KernelVersion: 2.6.26 diff --git a/Documentation/usb/authorization.txt b/Documentation/usb/authorization.txt index c069b6884c77..c7e985f05d8f 100644 --- a/Documentation/usb/authorization.txt +++ b/Documentation/usb/authorization.txt @@ -90,3 +90,34 @@ etc, but you get the idea. Anybody with access to a device gadget kit can fake descriptors and device info. Don't trust that. You are welcome. + +Interface authorization +----------------------- +There is a similar approach to allow or deny specific USB interfaces. +That allows to block only a subset of an USB device. + +Authorize an interface: +$ echo 1 > /sys/bus/usb/devices/INTERFACE/authorized + +Deauthorize an interface: +$ echo 0 > /sys/bus/usb/devices/INTERFACE/authorized + +The default value for new interfaces +on a particular USB bus can be changed, too. + +Allow interfaces per default: +$ echo 1 > /sys/bus/usb/devices/usbX/interface_authorized_default + +Deny interfaces per default: +$ echo 0 > /sys/bus/usb/devices/usbX/interface_authorized_default + +Per default the interface_authorized_default bit is 1. +So all interfaces would authorized per default. + +Note: +If a deauthorized interface will be authorized so the driver probing must +be triggered manually by writing INTERFACE to /sys/bus/usb/drivers_probe + +For drivers that need multiple interfaces all needed interfaces should be +authroized first. After that the drivers should be probed. +This avoids side effects. |