core-agent-linux/passwordless-root/pam.d_su.qubes

#%PAM-1.0
auth		sufficient	pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth		sufficient	pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
#auth		required	pam_wheel.so use_uid

# {{ Qubes specific modifications begin here
#    Prevent su from asking for password
#    (by package qubes-core-agent-passwordless-root).
auth    	sufficient	pam_succeed_if.so use_uid user ingroup qubes
# }} Qubes specific modifications end here

auth		substack	system-auth
auth		include		postlogin
account		sufficient	pam_succeed_if.so uid = 0 use_uid quiet
account		include		system-auth
password	include		system-auth
session		include		system-auth
session		include		postlogin
session		optional	pam_xauth.so