selinux-policy/policy/mls

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ifdef(`enable_mls',`
#
# Define sensitivities
#
# Domination of sensitivities is in increasin
# numerical order, with s0 being the lowest
gen_sens(mls_num_sens)
#
# Define the categories
#
# Generate declarations
gen_cats(mls_num_cats)
#
# Each MLS level specifies a sensitivity and zero or more categories which may
# be associated with that sensitivity.
#
# Generate levels from all sensitivities
# with all categories
gen_levels(mls_num_sens,mls_num_cats)
#
# Define the MLS policy
#
# mlsconstrain class_set perm_set expression ;
#
# mlsvalidatetrans class_set expression ;
#
# expression : ( expression )
# | not expression
# | expression and expression
# | expression or expression
# | u1 op u2
# | r1 role_mls_op r2
# | t1 op t2
# | l1 role_mls_op l2
# | l1 role_mls_op h2
# | h1 role_mls_op l2
# | h1 role_mls_op h2
# | l1 role_mls_op h1
# | l2 role_mls_op h2
# | u1 op names
# | u2 op names
# | r1 op names
# | r2 op names
# | t1 op names
# | t2 op names
# | u3 op names (NOTE: this is only available for mlsvalidatetrans)
# | r3 op names (NOTE: this is only available for mlsvalidatetrans)
# | t3 op names (NOTE: this is only available for mlsvalidatetrans)
#
# op : == | !=
# role_mls_op : == | != | eq | dom | domby | incomp
#
# names : name | { name_list }
# name_list : name | name_list name
#
#
# MLS policy for the file classes
#
# make sure these file classes are "single level"
mlsconstrain { file lnk_file fifo_file } { create relabelto }
( l2 eq h2 );
# new file labels must be dominated by the relabeling subjects clearance
mlsconstrain { dir file lnk_file chr_file blk_file sock_file fifo_file } relabelto
( h1 dom h2 );
# the file "read" ops (note the check is dominance of the low level)
mlsconstrain { dir file lnk_file chr_file blk_file sock_file fifo_file } { read getattr execute }
(( l1 dom l2 ) or
(( t1 == mlsfilereadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsfileread ) or
( t2 == mlstrustedobject ));
mlsconstrain dir search
(( l1 dom l2 ) or
(( t1 == mlsfilereadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsfileread ) or
( t2 == mlstrustedobject ));
# the "single level" file "write" ops
mlsconstrain { file lnk_file fifo_file dir chr_file blk_file sock_file } { write create setattr relabelfrom append unlink link rename mounton }
(( l1 eq l2 ) or
(( t1 == mlsfilewritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsfilewriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsfilewrite ) or
( t2 == mlstrustedobject ));
# Directory "write" ops
mlsconstrain dir { add_name remove_name reparent rmdir }
(( l1 eq l2 ) or
(( t1 == mlsfilewriteinrange ) and ( l1 dom l2 ) and ( l1 domby h2 )) or
(( t1 == mlsfilewritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsfilewrite ) or
( t2 == mlstrustedobject ));
# these access vectors have no MLS restrictions
# { dir file lnk_file chr_file blk_file sock_file fifo_file } { ioctl lock swapon quotaon }
#
# { file chr_file } { execute_no_trans entrypoint execmod }
# the file upgrade/downgrade rule
mlsvalidatetrans { dir file lnk_file chr_file blk_file sock_file fifo_file }
((( l1 eq l2 ) or
(( t3 == mlsfileupgrade ) and ( l1 domby l2 )) or
(( t3 == mlsfiledowngrade ) and ( l1 dom l2 )) or
(( t3 == mlsfiledowngrade ) and ( l1 incomp l2 ))) and
(( h1 eq h2 ) or
(( t3 == mlsfileupgrade ) and ( h1 domby h2 )) or
(( t3 == mlsfiledowngrade ) and ( h1 dom h2 )) or
(( t3 == mlsfiledowngrade ) and ( h1 incomp h2 ))));
# create can also require the upgrade/downgrade checks if the creating process
# has used setfscreate (note that both the high and low level of the object
# default to the process sensitivity level)
mlsconstrain { dir file lnk_file chr_file blk_file sock_file fifo_file } create
((( l1 eq l2 ) or
(( t1 == mlsfileupgrade ) and ( l1 domby l2 )) or
(( t1 == mlsfiledowngrade ) and ( l1 dom l2 )) or
(( t1 == mlsfiledowngrade ) and ( l1 incomp l2 ))) and
(( l1 eq h2 ) or
(( t1 == mlsfileupgrade ) and ( l1 domby h2 )) or
(( t1 == mlsfiledowngrade ) and ( l1 dom h2 )) or
(( t1 == mlsfiledowngrade ) and ( l1 incomp h2 ))));
#
# MLS policy for the filesystem class
#
# new filesystem labels must be dominated by the relabeling subjects clearance
mlsconstrain filesystem relabelto
( h1 dom h2 );
# the filesystem "read" ops (implicit single level)
mlsconstrain filesystem { getattr quotaget }
(( l1 dom l2 ) or
(( t1 == mlsfilereadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsfileread ));
# all the filesystem "write" ops (implicit single level)
mlsconstrain filesystem { mount remount unmount relabelfrom quotamod }
(( l1 eq l2 ) or
(( t1 == mlsfilewritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsfilewrite ));
# these access vectors have no MLS restrictions
# filesystem { transition associate }
#
# MLS policy for the socket classes
#
# new socket labels must be dominated by the relabeling subjects clearance
mlsconstrain { socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket unix_stream_socket unix_dgram_socket netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_ip6fw_socket netlink_dnrt_socket } relabelto
( h1 dom h2 );
# the socket "read+write" ops
# (Socket FDs are generally bidirectional, equivalent to open(..., O_RDWR),
# require equal levels for unprivileged subjects, or read *and* write overrides)
mlsconstrain { socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket unix_stream_socket unix_dgram_socket netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_ip6fw_socket netlink_dnrt_socket } { accept connect }
(( l1 eq l2 ) or
(((( t1 == mlsnetreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsnetread )) and
((( t1 == mlsnetwriteranged ) and ( l1 dom l2 ) and ( l1 domby h2 )) or
(( t1 == mlsnetwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsnetwrite ))));
# the socket "read" ops (note the check is dominance of the low level)
mlsconstrain { socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket unix_stream_socket unix_dgram_socket netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_ip6fw_socket netlink_dnrt_socket } { read getattr listen accept getopt recv_msg }
(( l1 dom l2 ) or
(( t1 == mlsnetreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsnetread ));
mlsconstrain { netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_xfrm_socket netlink_audit_socket netlink_ip6fw_socket } nlmsg_read
(( l1 dom l2 ) or
(( t1 == mlsnetreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsnetread ));
# the socket "write" ops
mlsconstrain { socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket unix_stream_socket unix_dgram_socket netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_ip6fw_socket netlink_dnrt_socket } { write setattr relabelfrom connect setopt shutdown }
(( l1 eq l2 ) or
(( t1 == mlsnetwriteranged ) and ( l1 dom l2 ) and ( l1 domby h2 )) or
(( t1 == mlsnetwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsnetwrite ));
# used by netlabel to restrict normal domains to same level connections
mlsconstrain { tcp_socket udp_socket rawip_socket } recvfrom
(( l1 eq l2 ) or
(( t1 == mlsnetreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsnetread ));
# these access vectors have no MLS restrictions
# { socket tcp_socket udp_socket rawip_socket netlink_socket packet_socket key_socket unix_stream_socket unix_dgram_socket netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_nflog_socket netlink_xfrm_socket netlink_selinux_socket netlink_audit_socket netlink_ip6fw_socket netlink_dnrt_socket } { ioctl create lock append bind sendto send_msg name_bind }
#
# { tcp_socket udp_socket rawip_socket } node_bind
#
# { tcp_socket unix_stream_socket } { connectto newconn acceptfrom }
#
# tcp_socket name_connect
#
# { netlink_route_socket netlink_firewall_socket netlink_tcpdiag_socket netlink_xfrm_socket netlink_audit_socket netlink_ip6fw_socket } nlmsg_write
#
# netlink_audit_socket { nlmsg_relay nlmsg_readpriv }
#
# netlink_kobject_uevent_socket *
#
#
# MLS policy for the ipc classes
#
# the ipc "read" ops (implicit single level)
mlsconstrain { ipc sem msgq shm } { getattr read unix_read }
(( l1 dom l2 ) or
(( t1 == mlsipcreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsipcread ));
mlsconstrain msg receive
(( l1 dom l2 ) or
(( t1 == mlsipcreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsipcread ));
# the ipc "write" ops (implicit single level)
mlsconstrain { ipc sem msgq shm } { create destroy setattr write unix_write }
(( l1 eq l2 ) or
(( t1 == mlsipcwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsipcwrite ));
mlsconstrain msgq enqueue
(( l1 eq l2 ) or
(( t1 == mlsipcwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsipcwrite ));
mlsconstrain shm lock
(( l1 eq l2 ) or
(( t1 == mlsipcwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsipcwrite ));
mlsconstrain msg send
(( l1 eq l2 ) or
(( t1 == mlsipcwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsipcwrite ));
# these access vectors have no MLS restrictions
# { ipc sem msgq shm } associate
#
# MLS policy for the fd class
#
# No sharing of open file descriptors between levels unless
# the process type is authorized to use fds created by
# other levels (mlsfduse) or the fd type is authorized to
# shared among levels (mlsfdshare).
mlsconstrain fd use (
l1 eq l2
or t1 == mlsfduse
or t2 == mlsfdshare
);
#
# MLS policy for the network object classes
#
# the netif/node "read" ops (implicit single level socket doing the read)
# (note the check is dominance of the low level)
mlsconstrain { node netif } { tcp_recv udp_recv rawip_recv }
(( l1 dom l2 ) or ( t1 == mlsnetrecvall ));
# the netif/node "write" ops (implicit single level socket doing the write)
mlsconstrain { netif node } { tcp_send udp_send rawip_send }
(( l1 eq l2 ) or
(( t1 == mlsnetwriteranged ) and ( l1 dom l2 ) and ( l1 domby h2 )));
# these access vectors have no MLS restrictions
# node enforce_dest
#
# MLS policy for the process class
#
# new process labels must be dominated by the relabeling subjects clearance
# and sensitivity level changes require privilege
mlsconstrain process transition
(( h1 dom h2 ) and
(( l1 eq l2 ) or ( t1 == mlsprocsetsl ) or
(( t1 == privrangetrans ) and ( t2 == mlsrangetrans ))));
mlsconstrain process dyntransition
(( h1 dom h2 ) and
(( l1 eq l2 ) or ( t1 == mlsprocsetsl )));
# all the process "read" ops
mlsconstrain process { getsched getsession getpgid getcap getattr ptrace share }
(( l1 dom l2 ) or
(( t1 == mlsprocreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsprocread ));
# all the process "write" ops (note the check is equality on the low level)
mlsconstrain process { sigkill sigstop signal setsched setpgid setcap setexec setfscreate setcurrent ptrace share }
(( l1 eq l2 ) or
(( t1 == mlsprocwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsprocwrite ));
# these access vectors have no MLS restrictions
# process { fork sigchld signull noatsecure siginh setrlimit rlimitinh execmem execstack execheap }
#
# MLS policy for the security class
#
# these access vectors have no MLS restrictions
# security *
#
# MLS policy for the system class
#
# these access vectors have no MLS restrictions
# system *
#
# MLS policy for the capability class
#
# these access vectors have no MLS restrictions
# capability *
#
# MLS policy for the passwd class
#
# these access vectors have no MLS restrictions
# passwd *
#
# MLS policy for the drawable class
#
# the drawable "read" ops (implicit single level)
mlsconstrain drawable { getattr copy }
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinread ));
# the drawable "write" ops (implicit single level)
mlsconstrain drawable { create destroy draw copy }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the gc class
#
# the gc "read" ops (implicit single level)
mlsconstrain gc getattr
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinread ));
# the gc "write" ops (implicit single level)
mlsconstrain gc { create free setattr }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the window class
#
# the window "read" ops (implicit single level)
mlsconstrain window { listprop getattr enumerate mousemotion inputevent drawevent windowchangeevent windowchangerequest serverchangeevent extensionevent }
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinread ));
# the window "write" ops (implicit single level)
mlsconstrain window { addchild create destroy chstack chproplist chprop setattr setfocus move chselection chparent ctrllife transparent clientcomevent }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ) or
( t2 == mlstrustedobject ));
# these access vectors have no MLS restrictions
# window { map unmap }
#
# MLS policy for the font class
#
# the font "read" ops (implicit single level)
mlsconstrain font { load getattr }
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinread ));
# the font "write" ops (implicit single level)
mlsconstrain font free
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ));
# these access vectors have no MLS restrictions
# font use
#
# MLS policy for the colormap class
#
# the colormap "read" ops (implicit single level)
mlsconstrain colormap { list read getattr }
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinreadcolormap ) or
( t1 == mlsxwinread ));
# the colormap "write" ops (implicit single level)
mlsconstrain colormap { create free install uninstall store setattr }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwritecolormap ) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the property class
#
# the property "read" ops (implicit single level)
mlsconstrain property { read }
(( l1 dom l2 ) or
(( t1 == mlsxwinreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsxwinreadproperty ) or
( t1 == mlsxwinread ));
# the property "write" ops (implicit single level)
mlsconstrain property { create free write }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwriteproperty ) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the cursor class
#
# the cursor "write" ops (implicit single level)
mlsconstrain cursor { create createglyph free assign setattr }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the xclient class
#
# the xclient "write" ops (implicit single level)
mlsconstrain xclient kill
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the xinput class
#
# these access vectors have no MLS restrictions
# xinput ~{ relabelinput setattr }
# the xinput "write" ops (implicit single level)
mlsconstrain xinput { setattr relabelinput }
(( l1 eq l2 ) or
(( t1 == mlsxwinwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
( t1 == mlsxwinwritexinput ) or
( t1 == mlsxwinwrite ));
#
# MLS policy for the xserver class
#
# these access vectors have no MLS restrictions
# xserver *
#
# MLS policy for the xextension class
#
# these access vectors have no MLS restrictions
# xextension { query use }
#
# MLS policy for the pax class
#
# these access vectors have no MLS restrictions
# pax { pageexec emutramp mprotect randmmap randexec segmexec }
#
# MLS policy for the dbus class
#
# these access vectors have no MLS restrictions
# dbus { acquire_svc send_msg }
#
# MLS policy for the nscd class
#
# these access vectors have no MLS restrictions
# nscd { getpwd getgrp gethost getstat admin shmempwd shmemgrp shmemhost }
#
# MLS policy for the association class
#
mlsconstrain association { recvfrom }
((( l1 dom l2 ) and ( l1 domby h2 )) or
(( t1 == mlsnetreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsnetread ) or
( t2 == unlabeled_t ));
mlsconstrain association { sendto }
(( l1 eq l2 ) or
(( t1 == mlsnetwriteranged ) and ( l1 dom l2 ) and ( l1 domby h2 )) or
( t2 == unlabeled_t ));
mlsconstrain association { polmatch }
(( l1 dom l2 ) and ( h1 domby h2 ));
#
# MLS policy for the context class
#
mlsconstrain context translate
(( h1 dom h2 ) or ( t1 == mlstranslate ));
mlsconstrain context contains
( h1 dom h2 );
#
# MLS policy for database classes
#
# make sure these database classes are "single level"
mlsconstrain { db_database db_table db_procedure db_column db_blob } { create relabelto }
( l2 eq h2 );
mlsconstrain { db_tuple } { insert relabelto }
( l2 eq h2 );
# new database labels must be dominated by the relabeling subjects clearance
mlsconstrain { db_database db_table db_procedure db_column db_tuple db_blob } { relabelto }
( h1 dom h2 );
# the database "read" ops (note the check is dominance of the low level)
mlsconstrain { db_database } { getattr access get_param }
(( l1 dom l2 ) or
(( t1 == mlsdbreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsdbread ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_table db_column } { getattr use select }
(( l1 dom l2 ) or
(( t1 == mlsdbreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsdbread ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_procedure } { getattr execute }
(( l1 dom l2 ) or
(( t1 == mlsdbreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsdbread ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_blob } { getattr read }
(( l1 dom l2 ) or
(( t1 == mlsdbreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsdbread ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_tuple } { use select }
(( l1 dom l2 ) or
(( t1 == mlsdbreadtoclr ) and ( h1 dom l2 )) or
( t1 == mlsdbread ) or
( t2 == mlstrustedobject ));
# the "single level" file "write" ops
mlsconstrain { db_database } { create drop setattr relabelfrom install_module load_module set_param }
(( l1 eq l2 ) or
(( t1 == mlsdbwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsdbwriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsdbwrite ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_table } { create drop setattr relabelfrom update insert delete lock }
(( l1 eq l2 ) or
(( t1 == mlsdbwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsdbwriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsdbwrite ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_column } { create drop setattr relabelfrom update insert }
(( l1 eq l2 ) or
(( t1 == mlsdbwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsdbwriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsdbwrite ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_blob } { create drop setattr relabelfrom write import export }
(( l1 eq l2 ) or
(( t1 == mlsdbwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsdbwriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsdbwrite ) or
( t2 == mlstrustedobject ));
mlsconstrain { db_tuple } { relabelfrom update insert delete }
(( l1 eq l2 ) or
(( t1 == mlsdbwritetoclr ) and ( h1 dom l2 ) and ( l1 domby l2 )) or
(( t2 == mlsdbwriteinrange ) and ( l1 dom l2 ) and ( h1 domby h2 )) or
( t1 == mlsdbwrite ) or
( t2 == mlstrustedobject ));
# the database upgrade/downgrade rule
mlsvalidatetrans { db_database db_table db_procedure db_column db_tuple db_blob }
((( l1 eq l2 ) or
(( t3 == mlsdbupgrade ) and ( l1 domby l2 )) or
(( t3 == mlsdbdowngrade ) and ( l1 dom l2 )) or
(( t3 == mlsdbdowngrade ) and ( l1 incomp l2 ))) and
(( l1 eq h2 ) or
(( t3 == mlsdbupgrade ) and ( h1 domby h2 )) or
(( t3 == mlsdbdowngrade ) and ( h1 dom h2 )) or
(( t3 == mlsdbdowngrade ) and ( h1 incomp h2 ))));
') dnl end enable_mls