Description of problem:
The 'hp' CUPS backend needs to use USB device files to do its job.

Version-Release number of selected component (if applicable):
selinux-policy-targeted-2.2.23-15

How reproducible:
100%

Steps to Reproduce:
1. setenforce 0
2. Run /usr/lib/cups/backend/hp (with HP multi-function device plugged in)
  
Actual results:
audit(1143543819.520:190): avc:  denied  { read write } for  pid=27691
comm="hpiod" name="001" dev=tmpfs ino=3990 scontext=user_u:system_r:hplip_t:s0
tcontext=system_u:object_r:usb_device_t:s0 tclass=chr_file
audit(1143543819.520:191): avc:  denied  { ioctl } for  pid=27691 comm="hpiod"
name="001" dev=tmpfs ino=3990 scontext=user_u:system_r:hplip_t:s0
tcontext=system_u:object_r:usb_device_t:s0 tclass=chr_file

(With 'setenforce 1', no device is found.)

Additional info:
This should fix it:

allow hplip_t usb_device_t:chr_file { ioctl read write };