OpenZFS 4185 - add new cryptographic checksums to ZFS: SHA-512, Skein, Edon-R

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Garrett D'Amore <garrett@damore.org>
Ported by: Tony Hutter <hutter2@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/4185
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/45818ee

Porting Notes:
This code is ported on top of the Illumos Crypto Framework code:

    https://github.com/zfsonlinux/zfs/pull/4329/commits/b5e030c8dbb9cd393d313571dee4756fbba8c22d

The list of porting changes includes:

- Copied module/icp/include/sha2/sha2.h directly from illumos

- Removed from module/icp/algs/sha2/sha2.c:
	#pragma inline(SHA256Init, SHA384Init, SHA512Init)

- Added 'ctx' to lib/libzfs/libzfs_sendrecv.c:zio_checksum_SHA256() since
  it now takes in an extra parameter.

- Added CTASSERT() to assert.h from for module/zfs/edonr_zfs.c

- Added skein & edonr to libicp/Makefile.am

- Added sha512.S.  It was generated from sha512-x86_64.pl in Illumos.

- Updated ztest.c with new fletcher_4_*() args; used NULL for new CTX argument.

- In icp/algs/edonr/edonr_byteorder.h, Removed the #if defined(__linux) section
  to not #include the non-existant endian.h.

- In skein_test.c, renane NULL to 0 in "no test vector" array entries to get
  around a compiler warning.

- Fixup test files:
	- Rename <sys/varargs.h> -> <varargs.h>, <strings.h> -> <string.h>,
	- Remove <note.h> and define NOTE() as NOP.
	- Define u_longlong_t
	- Rename "#!/usr/bin/ksh" -> "#!/bin/ksh -p"
	- Rename NULL to 0 in "no test vector" array entries to get around a
	  compiler warning.
	- Remove "for isa in $($ISAINFO); do" stuff
	- Add/update Makefiles
	- Add some userspace headers like stdio.h/stdlib.h in places of
	  sys/types.h.

- EXPORT_SYMBOL *_Init/*_Update/*_Final... routines in ICP modules.

- Update scripts/zfs2zol-patch.sed

- include <sys/sha2.h> in sha2_impl.h

- Add sha2.h to include/sys/Makefile.am

- Add skein and edonr dirs to icp Makefile

- Add new checksums to zpool_get.cfg

- Move checksum switch block from zfs_secpolicy_setprop() to
  zfs_check_settable()

- Fix -Wuninitialized error in edonr_byteorder.h on PPC

- Fix stack frame size errors on ARM32
  	- Don't unroll loops in Skein on 32-bit to save stack space
  	- Add memory barriers in sha2.c on 32-bit to save stack space

- Add filetest_001_pos.ksh checksum sanity test

- Add option to write psudorandom data in file_write utility

module/zfs/spa.c

@@ -25,6 +25,7 @@
  * Copyright (c) 2015, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013, 2014, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
+ * Copyright 2013 Saso Kiselkov. All rights reserved.
  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
  */
 
@@ -2675,6 +2676,19 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
 		return (spa_load(spa, state, SPA_IMPORT_EXISTING, B_TRUE));
 	}
 
+	/* Grab the checksum salt from the MOS. */
+	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+	    DMU_POOL_CHECKSUM_SALT, 1,
+	    sizeof (spa->spa_cksum_salt.zcs_bytes),
+	    spa->spa_cksum_salt.zcs_bytes);
+	if (error == ENOENT) {
+		/* Generate a new salt for subsequent use */
+		(void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+		    sizeof (spa->spa_cksum_salt.zcs_bytes));
+	} else if (error != 0) {
+		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+	}
+
 	if (spa_dir_prop(spa, DMU_POOL_SYNC_BPOBJ, &obj) != 0)
 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 	error = bpobj_open(&spa->spa_deferred_bpobj, spa->spa_meta_objset, obj);
@@ -3929,6 +3943,12 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	if (version >= SPA_VERSION_ZPOOL_HISTORY)
 		spa_history_create_obj(spa, tx);
 
+	/*
+	 * Generate some random noise for salted checksums to operate on.
+	 */
+	(void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+	    sizeof (spa->spa_cksum_salt.zcs_bytes));
+
 	/*
 	 * Set pool properties.
 	 */
@@ -6406,6 +6426,20 @@ spa_sync_upgrades(spa_t *spa, dmu_tx_t *tx)
 		if (lz4_en && !lz4_ac)
 			spa_feature_incr(spa, SPA_FEATURE_LZ4_COMPRESS, tx);
 	}
+
+	/*
+	 * If we haven't written the salt, do so now.  Note that the
+	 * feature may not be activated yet, but that's fine since
+	 * the presence of this ZAP entry is backwards compatible.
+	 */
+	if (zap_contains(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+	    DMU_POOL_CHECKSUM_SALT) == ENOENT) {
+		VERIFY0(zap_add(spa->spa_meta_objset,
+		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CHECKSUM_SALT, 1,
+		    sizeof (spa->spa_cksum_salt.zcs_bytes),
+		    spa->spa_cksum_salt.zcs_bytes, tx));
+	}
+
 	rrw_exit(&dp->dp_config_rwlock, FTAG);
 }