Allow additional map permission when reading hwdb

I'm seeing a denial for udev to map /etc/udev/hwdb.bin.
This creates and uses a new interface to allow the needed
permission for udev.

type=AVC msg=audit(1551886176.948:642): avc:  denied  { map } for  pid=5187 comm="systemd-udevd" path="/etc/udev/hwdb.bin" dev="dm-1" ino=6509618 scontext=system_u:system_r:udev_t:s0-s0:c0.c1023 tcontext=system_u:object_r:systemd_hwdb_t:s0 tclass=file permissive=1

Updated from previous to create a new interface.

Signed-off-by: Dave Sugar <dsugar@tresys.com>

policy/modules/system/systemd.if

@@ -37,6 +37,24 @@ interface(`systemd_read_hwdb',`
 	read_files_pattern($1, systemd_hwdb_t, systemd_hwdb_t)
 ')
 
+#######################################
+## <summary>
+##  Allow domain to map udev hwdb file
+## </summary>
+## <param name="domain">
+## <summary>
+##  domain allowed access
+## </summary>
+## </param>
+#
+interface(`systemd_map_hwdb',`
+	gen_require(`
+		type systemd_hwdb_t;
+	')
+
+	allow $1 systemd_hwdb_t:file map;
+')
+
 ######################################
 ## <summary>
 ##   Read systemd_login PID files.

policy/modules/system/udev.te

@@ -248,6 +248,7 @@ ifdef(`init_systemd',`
 	init_get_generic_units_status(udev_t)
 	init_stream_connect(udev_t)
 
+	systemd_map_hwdb(udev_t)
 	systemd_read_hwdb(udev_t)
 	systemd_read_logind_sessions_files(udev_t)
 	systemd_read_logind_pids(udev_t)