selinux: adjust utils to run restorecon with -Z

cp, mv, install, mkdir, mkfifo, mknod are adjusted so that:
 -Z no longer accepts an argument.
 -Z or --context without an argument do not warn without SELinux.
 --context with an argument will warn without SELinux.

* src/local.mk: Reference the new selinux module where required.
* src/system.h: Make the argument to --context optional.
* src/mkdir.c: Likewise.  Also handle the SMACK case for --context.
Note we currently silently ignore -Z with SMACK.
* src/mkfifo.c: Likewise.
* src/mknod.c: Likewise.
* src/install.c: Likewise.  Note install(1) by default already
set the context for target files to their system default,
albeit with an older method.  Use the -Z option to select between
the old and new context restoration behavior, and document
the differences and details for how context restoration
is done in new and old methods, with a view disabling the
old method entirely in future.
* src/cp.c: Make the argument to --context optional.
Note -Z implies --no-preserve=context.  I.E. -Z overrides
that aspect of -a no matter what order specified.
(struct cp_options): Document the context handling options.
(main): Check/adjust option combinations after all
options are processed, to both simplify processing
and to make handling independent of order of options
on the command line.  Also improve the diagnostics
from a failed call to setfscreatecon().
(set_process_security_ctx): A new function,
refactored to set the default context from the source file,
or with the type adjusted as per the system default for
the destination path.
(set_file_security_ctx): A new function refactored to
set the security context of an existing file, either based on
the process context or the default system context for a path.
(copy_internal): Use the refactored functions to simplify
error handling and consistently fail or warn as needed.
(copy_reg): Likewise.
(copy_internal): With --preserve=context, also copy
context from non regular files.  Note for directories this may
impact the copying of subsequent files to that directory?
(copy_attr): If we're handling SELinux explicitly,
then exclude to avoid the redudant copy with --preserve=context,
and the problematic copy with -Z.  Note SELinux attribute exclusion
also now honors cp -a --no-preserve=context.  Note there was a
very small window over 10 years ago, where attr_copy_file was
available, while attr_copy_check_permissions was not, so we
don't bother adding an explicit m4 check for the latter function.
* src/mv.c: Support --context, but don't allow specifying an argument.
* src/chcon.c: Adjust a comment to be specific to SELinux.
* src/runcon.c: Likewise.
* src/copy.c: Honor the context settings to "restorecon" as appropriate.
* src/copy.h: Add a new setting to select "restorecon" functionality.
* tests/mkdir/selinux.sh: s/-Z/--context=/
* tests/cp/cp-a-selinux.sh: Augment this test with cases
testing basic -Z functionality, and also test the various
invalid option combinations and option precedence.
* tests/mkdir/restorecon.sh: Add a new test for the
more involved mkdir -Z handling, since the directory changing
and non existent directories need to be specially handled.
Also check the similar but simpler handling of -Z by mk{nod,fifo}.
* tests/local.mk: Reference the new test.
* doc/coreutils.texi (cp invocation): Update as per interface changes.
(mv invocation): Likewise.
(install invocation): Likewise.
(mkfifo invocation): Likewise.
(mknod invocation): Likewise.
(mkdir invocation): Likewise.
* NEWS: Mention the new feature and change in behavior.

1 files changed, 38 insertions, 14 deletions

diff --git a/src/mkfifo.c b/src/mkfifo.c
index 4c6dac468..df97d6baa 100644
--- a/src/mkfifo.c
+++ b/src/mkfifo.c
@@ -26,6 +26,7 @@
 #include "error.h"
 #include "modechange.h"
 #include "quote.h"
+#include "selinux.h"
 #include "smack.h"
 
 /* The official name of this program (e.g., no 'g' prefix).  */
@@ -60,7 +61,8 @@ Create named pipes (FIFOs) with the given NAMEs.\n\
   -m, --mode=MODE    set file permission bits to MODE, not a=rw - umask\n\
 "), stdout);
       fputs (_("\
-  -Z, --context=CTX  set the SELinux security context of each NAME to CTX\n\
+  -Z, --context[=CTX]  set the SELinux security context of each NAME to\n\
+                         default type, or CTX if specified\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
@@ -77,6 +79,7 @@ main (int argc, char **argv)
   int exit_status = EXIT_SUCCESS;
   int optc;
   security_context_t scontext = NULL;
+  bool set_security_context = false;
 
   initialize_main (&argc, &argv);
   set_program_name (argv[0]);
@@ -86,7 +89,7 @@ main (int argc, char **argv)
 
   atexit (close_stdout);
 
-  while ((optc = getopt_long (argc, argv, "m:Z:", longopts, NULL)) != -1)
+  while ((optc = getopt_long (argc, argv, "m:Z", longopts, NULL)) != -1)
     {
       switch (optc)
         {
@@ -94,7 +97,24 @@ main (int argc, char **argv)
           specified_mode = optarg;
           break;
         case 'Z':
-          scontext = optarg;
+          if (is_smack_enabled ())
+            {
+              /* We don't yet support -Z to restore context with SMACK.  */
+              scontext = optarg;
+            }
+          else if (is_selinux_enabled () > 0)
+            {
+              if (optarg)
+                scontext = optarg;
+              else
+                set_security_context = true;
+            }
+          else if (optarg)
+            {
+              error (0, 0,
+                     _("warning: ignoring --context; "
+                       "it requires an SELinux/SMACK-enabled kernel"));
+            }
           break;
         case_GETOPT_HELP_CHAR;
         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
@@ -140,17 +160,21 @@ main (int argc, char **argv)
     }
 
   for (; optind < argc; ++optind)
-    if (mkfifo (argv[optind], newmode) != 0)
-      {
-        error (0, errno, _("cannot create fifo %s"), quote (argv[optind]));
-        exit_status = EXIT_FAILURE;
-      }
-    else if (specified_mode && lchmod (argv[optind], newmode) != 0)
-      {
-        error (0, errno, _("cannot set permissions of `%s'"),
-               quote (argv[optind]));
-        exit_status = EXIT_FAILURE;
-      }
+    {
+      if (set_security_context)
+        defaultcon (argv[optind], S_IFIFO);
+      if (mkfifo (argv[optind], newmode) != 0)
+        {
+          error (0, errno, _("cannot create fifo %s"), quote (argv[optind]));
+          exit_status = EXIT_FAILURE;
+        }
+      else if (specified_mode && lchmod (argv[optind], newmode) != 0)
+        {
+          error (0, errno, _("cannot set permissions of `%s'"),
+                 quote (argv[optind]));
+          exit_status = EXIT_FAILURE;
+        }
+    }
 
   exit (exit_status);
 }