tests: support non-MLS enabled SELinux systems

When running "make check" on a Linux system running SELinux with a
non-MLS policy, tests/mkdir/restorecon.sh test fails with:

  chcon: invalid context: root:object_r:tmp_t:s0: Invalid argument

Indeed in such a configuration, contexts cannot have ":s0" suffix.

* init.cfg (get_selinux_type): Refactor this function to here
from various tests.  Update to work with a non-MLS policy.
(mls_enabled_): A new function to detect if MLS is enabled.
(skip_if_mcstransd_is_running_): Update to not skip when
MLS is not enabled.
* tests/mkdir/restorecon.sh: Use a valid non-MLS context when needed.
* tests/install/install-Z-selinux.sh: Likewise.
* tests/cp/cp-a-selinux.sh: Likewise.
* tests/misc/selinux.sh: Likewise.
* tests/misc/chcon.sh: Skip if non-MLS as --range used throughout.
Fixes http://bugs.gnu.org/22631

1 files changed, 15 insertions, 3 deletions

diff --git a/init.cfg b/init.cfg
index db861944c..f2950efb0 100644
--- a/init.cfg
+++ b/init.cfg
@@ -128,6 +128,15 @@ require_selinux_()
   esac
 }
 
+# Return the SELinux type component if available
+get_selinux_type() { ls -Zd "$1" | sed -n 's/.*:\(.*_t\)[: ].*/\1/p'; }
+
+# Whether SELinux Multi Level Security is enabled
+mls_enabled_() {
+  sestatus 2>&1 |
+  grep 'Policy MLS status:.*enabled' > /dev/null
+}
+
 # Skip this test if we're not in SELinux "enforcing" mode.
 require_selinux_enforcing_()
 {
@@ -637,10 +646,13 @@ skip_if_mcstransd_is_running_()
   # and if it's running, skip this test.
   __ctx=$(stat --printf='%C\n' .) || framework_failure_
   case $__ctx in
-    *:*:*:*) ;; # four components is ok
-    *) # anything else probably means mcstransd is running
-        skip_ "unexpected context '$__ctx'; turn off mcstransd" ;;
+    *:*:*:*) __ctx_ok=1 ;; # four components is ok
+    *:*:*)  # three components is ok too if there is no MLS
+        mls_enabled_ && __ctk_ok=1 ;;
   esac
+
+  test "$__ctx_ok" ||
+   skip_ "unexpected context '$__ctx'; turn off mcstransd"
 }
 
 # Skip the current test if umask doesn't work as usual.