[systemd-devel] WebUSB

Felipe Balbi felipe.balbi at intel.com
Mon Jan 9 11:12:11 UTC 2017


I don't think we need to change anything in the kernel. What we need is
generic udev rule that fixes up permissions for the WebUSB Interface.

IIRC, WebUSB is implemented much like CDC ACM, however bInterfaceClass
is set to Vendor Specific. That should be enough to prevent CDC-ACM
driver from binding to WebUSB Interface.

Babu once showed me on WebUSB device but I can't recall if the
descriptors were setup as I mentioned above or not. Babu, care to
confirm?

thanks

"Poussa, Sakari" <sakari.poussa at intel.com> writes:
> +Balbi
>
> On 1/9/17, 11:37 AM, "Kenneth Rohde Christiansen" <kenneth.christiansen at gmail.com> wrote:
>
> Adding Sakari and Babu, who might want to add a few people from our side. 
>
> Cheers
>
> Kenneth
>
> On Mon, Jan 9, 2017 at 10:20 AM Lars Knudsen <larsgk at gmail.com> wrote:
>
>  Hi, 
>
>  I am currently looking into how we can make using WebUSB devices less painful for users on Linux.
>
>  The main purpose of WebUSB (as far as I can see) is to enable certain CDC (in particular - but not limited to) devices communicate directly with browsers visiting certain trusted sites (listed inside a binary object store - sent on initial handshake).
>
>  The spec is here: https://wicg.github.io/webusb/ (already running fine in chrome stable)
>
>  Examples:
>
>  https://www.youtube.com/watch?v=Z1Nk2hH2wFE
>
>  https://www.youtube.com/watch?v=o7wGt9RfHVA
>
>  https://twitter.com/denladeside/status/817451203076427783
>
>  I'm guessing the solution will consist of 2 parts:
>
>  1. make sure no WebUSB device is picked up by modemmanager (modemmanager task)
>
>  2. make sure that webusb devices will be somehow accessible to be used by a browser running with user permissions (current temp solution listed here: adding user to plugdev, adding 0664 permissions to device:
>  https://developers.google.com/web/updates/2016/03/access-usb-devices-on-the-web ) (udev/systemd task).
>
>  For 2. we need to either making all webusb devices accessible or find some other way the browsers can - in a generic way - gain access. In all cases, it's important that no USB interfaces has been pre-claimed by the system (e.g. by cdc_acm) or
>  it should be possible for the browser to throw off the claims.
>
>  thoughts?
>
>  br
>
>  Lars
>

-- 
balbi
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