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, 73 insertions, 3 deletions

diff --git a/tests/cp/cp-a-selinux.sh b/tests/cp/cp-a-selinux.sh
index e7bdcf1df..ac7bf1c3a 100755
--- a/tests/cp/cp-a-selinux.sh
+++ b/tests/cp/cp-a-selinux.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-# Ensure that cp -a and cp --preserve=context work properly.
+# Ensure that cp -Z, -a and cp --preserve=context work properly.
 # In particular, test on a writable NFS partition.
 # Check also locally if --preserve=context, -a and --preserve=all
 # does work
@@ -41,6 +41,45 @@ test -s err && fail=1   #there must be no stderr output for -a
 ls -Z e | grep $ctx || fail=1
 ls -Z f | grep $ctx || fail=1
 
+# Check restorecon (-Z) functionality for file and directory
+get_selinux_type() { ls -Zd "$1" | sed -n 's/.*:\(.*_t\):.*/\1/p'; }
+# Also make a dir with our known context
+mkdir c_d || framework_failure_
+chcon $ctx c_d || framework_failure_
+# Get the type of this known context for file and dir
+old_type_f=$(get_selinux_type c)
+old_type_d=$(get_selinux_type c_d)
+# Setup copies for manipulation with restorecon
+# and get the adjusted type for comparison
+cp -a c Z1 || fail=1
+cp -a c_d Z1_d || fail=1
+if restorecon Z1 Z1_d 2>/dev/null; then
+  new_type_f=$(get_selinux_type Z1)
+  new_type_d=$(get_selinux_type Z1_d)
+
+  # Ensure -Z sets the type like restorecon does
+  cp -Z c Z2 || fail=1
+  cpZ_type_f=$(get_selinux_type Z2)
+  test "$cpZ_type_f" = "$new_type_f" || fail=1
+
+  # Ensuze -Z overrides -a and that dirs are handled too
+  cp -aZ c Z3 || fail=1
+  cp -aZ c_d Z3_d || fail=1
+  cpaZ_type_f=$(get_selinux_type Z3)
+  cpaZ_type_d=$(get_selinux_type Z3_d)
+  test "$cpaZ_type_f" = "$new_type_f" || fail=1
+  test "$cpaZ_type_d" = "$new_type_d" || fail=1
+
+  # Ensure -Z sets the type for existing files
+  mkdir -p existing/c_d || framework_failure_
+  touch existing/c || framework_failure_
+  cp -aZ c c_d existing || fail=1
+  cpaZ_type_f=$(get_selinux_type existing/c)
+  cpaZ_type_d=$(get_selinux_type existing/c_d)
+  test "$cpaZ_type_f" = "$new_type_f" || fail=1
+  test "$cpaZ_type_d" = "$new_type_d" || fail=1
+fi
+
 skip=0
 # Create a file system, then mount it with the context=... option.
 dd if=/dev/zero of=blob bs=8192 count=200    || skip=1
@@ -97,7 +136,7 @@ echo > g
 cp --preserve=context f g 2> out && fail=1
 # Here, we *do* expect the destination to be empty.
 test -s g && fail=1
-sed "s/ .g' to .*//" out > k
+sed "s/ .g'.*//" out > k
 mv k out
 compare exp out || fail=1
 
@@ -107,8 +146,39 @@ echo > g
 cp -a --preserve=context f g 2> out2 && fail=1
 # Here, we *do* expect the destination to be empty.
 test -s g && fail=1
-sed "s/ .g' to .*//" out2 > k
+sed "s/ .g'.*//" out2 > k
 mv k out2
 compare exp out2 || fail=1
 
+for no_g_cmd in '' 'rm -f g'; do
+  # restorecon equivalent.  Note even though the context
+  # returned from matchpathcon() will not match $ctx
+  # the resulting ENOTSUP warning will be suppressed.
+   # With absolute path
+  $no_g_cmd
+  cp -Z f $(realpath g) || fail=1
+   # With relative path
+  $no_g_cmd
+  cp -Z f g || fail=1
+   # -Z overrides -a
+  $no_g_cmd
+  cp -Z -a f g || fail=1
+   # -Z doesn't take an arg
+  $no_g_cmd
+  cp -Z "$ctx" f g && fail=1
+
+  # Explicit context
+  $no_g_cmd
+   # Explicitly defaulting to the global $ctx should work
+  cp --context="$ctx" f g || fail=1
+   # --context overrides -a
+  $no_g_cmd
+  cp -a --context="$ctx" f g || fail=1
+done
+
+# Mutually exlusive options
+cp -Z --preserve=context f g && fail=1
+cp --preserve=context -Z f g && fail=1
+cp --preserve=context --context="$ctx" f g && fail=1
+
 Exit $fail