Address SELinux denials for usbforward

denied { read write } for comm="usbforward" name="vport0p2" dev="tmpfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:device:s0 tclass=chr_file
denied { read } for comm="usbforward" name="/" dev="tmpfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:device:s0 tclass=dir
denied { read } for comm="usbforward" name="usb" dev="tmpfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:usb_device:s0 tclass=dir
denied { create } for comm="usbforward" scontext=u:r:usbforward:s0 tcontext=u:r:usbforward:s0 tclass=netlink_kobject_uevent_socket
denied { read } for comm="usbforward" name="devices" dev="sysfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:sysfs:s0 tclass=dir
denied { open } for comm="usbforward" path="/sys/bus/usb/devices" dev="sysfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:sysfs:s0
denied { read } for comm="usbforward" name="busnum" dev="sysfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:sysfs:s0 tclass=file
denied { open } for comm="usbforward" path="/sys/devices/platform/dummy_hcd.0/usb1/1-1/busnum" dev="sysfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:sysfs:s0 tclass=file
denied { getattr } for comm="usbforward" path="/sys/devices/platform/dummy_hcd.0/usb1/1-1/busnum" dev="sysfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:sysfs:s0 tclass=file
denied { read write } for comm="usbforward" name="002" dev="tmpfs" scontext=u:r:usbforward:s0 tcontext=u:object_r:usb_device:s0 tclass=chr_file

Test: Device boots, no SELinux denials for usbforward
Bug: 28053261
Change-Id: I794b628d380df459cc527156870fbeff57264418
3 files changed