Add `zfs allow` and `zfs unallow` support

ZFS allows for specific permissions to be delegated to normal users
with the `zfs allow` and `zfs unallow` commands.  In addition, non-
privileged users should be able to run all of the following commands:

  * zpool [list | iostat | status | get]
  * zfs [list | get]

Historically this functionality was not available on Linux.  In order
to add it the secpolicy_* functions needed to be implemented and mapped
to the equivalent Linux capability.  Only then could the permissions on
the `/dev/zfs` be relaxed and the internal ZFS permission checks used.

Even with this change some limitations remain.  Under Linux only the
root user is allowed to modify the namespace (unless it's a private
namespace).  This means the mount, mountpoint, canmount, unmount,
and remount delegations cannot be supported with the existing code.  It
may be possible to add this functionality in the future.

This functionality was validated with the cli_user and delegation test
cases from the ZFS Test Suite.  These tests exhaustively verify each
of the supported permissions which can be delegated and ensures only
an authorized user can perform it.

Two minor bug fixes were required for test-running.py.  First, the
Timer() object cannot be safely created in a `try:` block when there
is an unconditional `finally` block which references it.  Second,
when running as a normal user also check for scripts using the
both the .ksh and .sh suffixes.

Finally, existing users who are simulating delegations by setting
group permissions on the /dev/zfs device should revert that
customization when updating to a version with this change.

Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Closes #362 
Closes #434 
Closes #4100
Closes #4394 
Closes #4410 
Closes #4487 

4 files changed, 6 insertions, 48 deletions

diff --git a/lib/libspl/include/Makefile.am b/lib/libspl/include/Makefile.am
index 626a8f46b..7882c1b9c 100644
--- a/lib/libspl/include/Makefile.am
+++ b/lib/libspl/include/Makefile.am
@@ -12,7 +12,6 @@ libspl_HEADERS = \
 	$(top_srcdir)/lib/libspl/include/limits.h \
 	$(top_srcdir)/lib/libspl/include/locale.h \
 	$(top_srcdir)/lib/libspl/include/note.h \
-	$(top_srcdir)/lib/libspl/include/priv.h \
 	$(top_srcdir)/lib/libspl/include/statcommon.h \
 	$(top_srcdir)/lib/libspl/include/stdio.h \
 	$(top_srcdir)/lib/libspl/include/stdlib.h \
diff --git a/lib/libspl/include/priv.h b/lib/libspl/include/priv.h
deleted file mode 100644
index 15b76a400..000000000
--- a/lib/libspl/include/priv.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * CDDL HEADER START
- *
- * The contents of this file are subject to the terms of the
- * Common Development and Distribution License, Version 1.0 only
- * (the "License").  You may not use this file except in compliance
- * with the License.
- *
- * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
- * or http://www.opensolaris.org/os/licensing.
- * See the License for the specific language governing permissions
- * and limitations under the License.
- *
- * When distributing Covered Code, include this CDDL HEADER in each
- * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
- * If applicable, add the following below this CDDL HEADER, with the
- * fields enclosed by brackets "[]" replaced with your own identifying
- * information: Portions Copyright [yyyy] [name of copyright owner]
- *
- * CDDL HEADER END
- */
-/*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
- * Use is subject to license terms.
- */
-
-#ifndef _LIBSPL_PRIV_H
-#define	_LIBSPL_PRIV_H
-
-#include <sys/types.h>
-
-/* Couldn't find this definition in OpenGrok */
-#define	PRIV_SYS_CONFIG	"sys_config"
-
-/*
- * priv_op_t indicates a privilege operation type
- */
-typedef enum priv_op {
-	PRIV_ON,
-	PRIV_OFF,
-	PRIV_SET
-} priv_op_t;
-
-static inline boolean_t priv_ineffect(const char *priv) { return B_TRUE; }
-
-#endif
diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index cc26927eb..87f79a532 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -43,7 +43,6 @@
 #include <fcntl.h>
 #include <sys/mntent.h>
 #include <sys/mount.h>
-#include <priv.h>
 #include <pwd.h>
 #include <grp.h>
 #include <stddef.h>
diff --git a/lib/libzpool/kernel.c b/lib/libzpool/kernel.c
index 5d6bdf251..800cdd7d7 100644
--- a/lib/libzpool/kernel.c
+++ b/lib/libzpool/kernel.c
@@ -1306,6 +1306,12 @@ zfs_secpolicy_destroy_perms(const char *name, cred_t *cr)
 	return (0);
 }
 
+int
+secpolicy_zfs(const cred_t *cr)
+{
+	return (0);
+}
+
 ksiddomain_t *
 ksid_lookupdomain(const char *dom)
 {