xref: /freebsd/sys/contrib/openzfs/module/zfs/edonr_zfs.c (revision aa1a8ff2d6dbc51ef058f46f3db5a8bb77967145)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2013 Saso Kiselkov.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 /*
26  * Copyright (c) 2016 by Delphix. All rights reserved.
27  */
28 #include <sys/zfs_context.h>
29 #include <sys/zio.h>
30 #include <sys/zio_checksum.h>
31 #include <sys/edonr.h>
32 #include <sys/abd.h>
33 
34 #define	EDONR_MODE		512
35 #define	EDONR_BLOCK_SIZE	EdonR512_BLOCK_SIZE
36 
37 static int
38 edonr_incremental(void *buf, size_t size, void *arg)
39 {
40 	EdonRState *ctx = arg;
41 	EdonRUpdate(ctx, buf, size * 8);
42 	return (0);
43 }
44 
45 /*
46  * Native zio_checksum interface for the Edon-R hash function.
47  */
48 void
49 abd_checksum_edonr_native(abd_t *abd, uint64_t size,
50     const void *ctx_template, zio_cksum_t *zcp)
51 {
52 	uint8_t		digest[EDONR_MODE / 8];
53 	EdonRState	ctx;
54 
55 	ASSERT(ctx_template != NULL);
56 	memcpy(&ctx, ctx_template, sizeof (ctx));
57 	(void) abd_iterate_func(abd, 0, size, edonr_incremental, &ctx);
58 	EdonRFinal(&ctx, digest);
59 	memcpy(zcp->zc_word, digest, sizeof (zcp->zc_word));
60 }
61 
62 /*
63  * Byteswapped zio_checksum interface for the Edon-R hash function.
64  */
65 void
66 abd_checksum_edonr_byteswap(abd_t *abd, uint64_t size,
67     const void *ctx_template, zio_cksum_t *zcp)
68 {
69 	zio_cksum_t	tmp;
70 
71 	abd_checksum_edonr_native(abd, size, ctx_template, &tmp);
72 	zcp->zc_word[0] = BSWAP_64(zcp->zc_word[0]);
73 	zcp->zc_word[1] = BSWAP_64(zcp->zc_word[1]);
74 	zcp->zc_word[2] = BSWAP_64(zcp->zc_word[2]);
75 	zcp->zc_word[3] = BSWAP_64(zcp->zc_word[3]);
76 }
77 
78 void *
79 abd_checksum_edonr_tmpl_init(const zio_cksum_salt_t *salt)
80 {
81 	EdonRState	*ctx;
82 	uint8_t		salt_block[EDONR_BLOCK_SIZE];
83 
84 	/*
85 	 * Edon-R needs all but the last hash invocation to be on full-size
86 	 * blocks, but the salt is too small. Rather than simply padding it
87 	 * with zeros, we expand the salt into a new salt block of proper
88 	 * size by double-hashing it (the new salt block will be composed of
89 	 * H(salt) || H(H(salt))).
90 	 */
91 	_Static_assert(EDONR_BLOCK_SIZE == 2 * (EDONR_MODE / 8),
92 	    "Edon-R block size mismatch");
93 	EdonRHash(salt->zcs_bytes, sizeof (salt->zcs_bytes) * 8, salt_block);
94 	EdonRHash(salt_block, EDONR_MODE, salt_block + EDONR_MODE / 8);
95 
96 	/*
97 	 * Feed the new salt block into the hash function - this will serve
98 	 * as our MAC key.
99 	 */
100 	ctx = kmem_zalloc(sizeof (*ctx), KM_SLEEP);
101 	EdonRInit(ctx);
102 	EdonRUpdate(ctx, salt_block, sizeof (salt_block) * 8);
103 	return (ctx);
104 }
105 
106 void
107 abd_checksum_edonr_tmpl_free(void *ctx_template)
108 {
109 	EdonRState *ctx = ctx_template;
110 
111 	memset(ctx, 0, sizeof (*ctx));
112 	kmem_free(ctx, sizeof (*ctx));
113 }
114