Re: [PATCH v2 14/19] driver core: Accept device trust policy by driver name

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [High] usb: core: usb_driver_claim_interface() ignores
  device_trust.driver=
--

commit 411f8a29f95104232dcf95e09cd04a0c125becd0
Author: Leon Romanovsky <leon@kernel.org>

driver core: Accept device trust policy by driver name

This commit adds the device_trust.driver= kernel command-line parameter to
configure initial device trust policies by bus and driver name, and checks
trust policy when claiming unregistered USB interfaces.

> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
> index ee36eae34bdcc..04b77691fbd7d 100644
> --- a/drivers/usb/core/driver.c
> +++ b/drivers/usb/core/driver.c
> @@ -563,6 +563,10 @@ int usb_driver_claim_interface(struct usb_driver *driver,
>  	if (!iface->authorized)
>  		return -ENODEV;
>  
> +	if (!device_is_registered(dev) &&
> +	    dev->trust_policy == DEVICE_TRUST_POLICY_DISABLED)
> +		return -EPERM;
> +
>  	dev->driver = &driver->driver;
>  	usb_set_intfdata(iface, data);
>  	iface->needs_binding = 0;

[Severity: High]
Does usb_driver_claim_interface() ignore device_trust.driver= rules when
checking an unregistered sibling interface?

In usb_set_configuration(), device_trust_init() sets each interface's
dev->trust_policy from device_trust.default= and device_trust= before the
device_add() loop, whereas device_trust.driver= is only evaluated in
__device_trust_prepare() during registration.

With device_trust.default=disabled and device_trust.driver=usb:<drv>=full,
probing interface 0 succeeds, but claiming an unregistered sibling from
probe() still sees DEVICE_TRUST_POLICY_DISABLED and fails with -EPERM.

Conversely, if device_trust.driver=usb:<drv>=disabled is set and interface
0 is allowed by a device_trust= entry, usb_driver_claim_interface() does
not reject the unregistered sibling claim with -EPERM.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261109-device-trust-core-v2-0-3b12d9a9f861@nvidia.com?part=14