usb: core: clear both ep_in and ep_out for non-ep0 control endpoints

Overview

In the Linux kernel, the following vulnerability has been resolved:

usb: core: clear both ep_in and ep_out for non-ep0 control endpoints

In usb_enable_endpoint(), non-zero control endpoints (where usb_endpoint_xfer_control(&ep->desc) is true) populate both dev->ep_in[epnum] and dev->ep_out[epnum] with the same struct usb_host_endpoint pointer.

However, usb_disable_endpoint() only clears either dev->ep_out[epnum] or dev->ep_in[epnum] depending on the direction bit of epaddr when reset_hardware is set, leaving the opposite direction's array slot pointing to the disabled/freed endpoint.

Clear both dev->ep_out[epnum] and dev->ep_in[epnum] when disabling a non-ep0 control endpoint with reset_hardware set, and update the function kerneldoc accordingly.

Tested in QEMU against Linux 7.3.0-rc3 using dummy_hcd and raw-gadget to enumerate a USB device with a non-zero control endpoint (bEndpointAddress 0x01, bmAttributes USB_ENDPOINT_XFER_CONTROL), verifying that both dev->ep_in[1] and dev->ep_out[1] are cleared when the interface is disabled.

Affected

• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7a9f61476b0e8002092a52ee8295edeeb0a28d1e
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1da16c46b8d7101b74bc2d72a04e23cf5c7ddea1
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c50413ecb662ea43c7f487632c8114721743a277
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0e8baa78d872f2db440d8b9ded946ab8dceb89eb
• Linux 2.6.12

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.