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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Cryptographic API.
4 *
5 * CRC32C chksum
6 *
7 *@Article{castagnoli-crc,
8 * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
9 * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
10 * and 32 Parity Bits}},
11 * journal = IEEE Transactions on Communication,
12 * year = {1993},
13 * volume = {41},
14 * number = {6},
15 * pages = {},
16 * month = {June},
17 *}
18 * Used by the iSCSI driver, possibly others, and derived from
19 * the iscsi-crc.c module of the linux-iscsi driver at
20 * http://linux-iscsi.sourceforge.net.
21 *
22 * Following the example of lib/crc32, this function is intended to be
23 * flexible and useful for all users. Modules that currently have their
24 * own crc32c, but hopefully may be able to use this one are:
25 * net/sctp (please add all your doco to here if you change to
26 * use this one!)
27 * <endoflist>
28 *
29 * Copyright (c) 2004 Cisco Systems, Inc.
30 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
31 */
32
33#include <asm/unaligned.h>
34#include <crypto/internal/hash.h>
35#include <linux/init.h>
36#include <linux/module.h>
37#include <linux/string.h>
38#include <linux/kernel.h>
39#include <linux/crc32.h>
40
41#define CHKSUM_BLOCK_SIZE 1
42#define CHKSUM_DIGEST_SIZE 4
43
44struct chksum_ctx {
45 u32 key;
46};
47
48struct chksum_desc_ctx {
49 u32 crc;
50};
51
52/*
53 * Steps through buffer one byte at a time, calculates reflected
54 * crc using table.
55 */
56
57static int chksum_init(struct shash_desc *desc)
58{
59 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
60 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
61
62 ctx->crc = mctx->key;
63
64 return 0;
65}
66
67/*
68 * Setting the seed allows arbitrary accumulators and flexible XOR policy
69 * If your algorithm starts with ~0, then XOR with ~0 before you set
70 * the seed.
71 */
72static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
73 unsigned int keylen)
74{
75 struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
76
77 if (keylen != sizeof(mctx->key))
78 return -EINVAL;
79 mctx->key = get_unaligned_le32(key);
80 return 0;
81}
82
83static int chksum_update(struct shash_desc *desc, const u8 *data,
84 unsigned int length)
85{
86 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
87
88 ctx->crc = __crc32c_le(ctx->crc, data, length);
89 return 0;
90}
91
92static int chksum_final(struct shash_desc *desc, u8 *out)
93{
94 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
95
96 put_unaligned_le32(~ctx->crc, out);
97 return 0;
98}
99
100static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
101{
102 put_unaligned_le32(~__crc32c_le(*crcp, data, len), out);
103 return 0;
104}
105
106static int chksum_finup(struct shash_desc *desc, const u8 *data,
107 unsigned int len, u8 *out)
108{
109 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
110
111 return __chksum_finup(&ctx->crc, data, len, out);
112}
113
114static int chksum_digest(struct shash_desc *desc, const u8 *data,
115 unsigned int length, u8 *out)
116{
117 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
118
119 return __chksum_finup(&mctx->key, data, length, out);
120}
121
122static int crc32c_cra_init(struct crypto_tfm *tfm)
123{
124 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
125
126 mctx->key = ~0;
127 return 0;
128}
129
130static struct shash_alg alg = {
131 .digestsize = CHKSUM_DIGEST_SIZE,
132 .setkey = chksum_setkey,
133 .init = chksum_init,
134 .update = chksum_update,
135 .final = chksum_final,
136 .finup = chksum_finup,
137 .digest = chksum_digest,
138 .descsize = sizeof(struct chksum_desc_ctx),
139 .base = {
140 .cra_name = "crc32c",
141 .cra_driver_name = "crc32c-generic",
142 .cra_priority = 100,
143 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
144 .cra_blocksize = CHKSUM_BLOCK_SIZE,
145 .cra_ctxsize = sizeof(struct chksum_ctx),
146 .cra_module = THIS_MODULE,
147 .cra_init = crc32c_cra_init,
148 }
149};
150
151static int __init crc32c_mod_init(void)
152{
153 return crypto_register_shash(&alg);
154}
155
156static void __exit crc32c_mod_fini(void)
157{
158 crypto_unregister_shash(&alg);
159}
160
161subsys_initcall(crc32c_mod_init);
162module_exit(crc32c_mod_fini);
163
164MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
165MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
166MODULE_LICENSE("GPL");
167MODULE_ALIAS_CRYPTO("crc32c");
168MODULE_ALIAS_CRYPTO("crc32c-generic");
1/*
2 * Cryptographic API.
3 *
4 * CRC32C chksum
5 *
6 *@Article{castagnoli-crc,
7 * author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
8 * title = {{Optimization of Cyclic Redundancy-Check Codes with 24
9 * and 32 Parity Bits}},
10 * journal = IEEE Transactions on Communication,
11 * year = {1993},
12 * volume = {41},
13 * number = {6},
14 * pages = {},
15 * month = {June},
16 *}
17 * Used by the iSCSI driver, possibly others, and derived from the
18 * the iscsi-crc.c module of the linux-iscsi driver at
19 * http://linux-iscsi.sourceforge.net.
20 *
21 * Following the example of lib/crc32, this function is intended to be
22 * flexible and useful for all users. Modules that currently have their
23 * own crc32c, but hopefully may be able to use this one are:
24 * net/sctp (please add all your doco to here if you change to
25 * use this one!)
26 * <endoflist>
27 *
28 * Copyright (c) 2004 Cisco Systems, Inc.
29 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
30 *
31 * This program is free software; you can redistribute it and/or modify it
32 * under the terms of the GNU General Public License as published by the Free
33 * Software Foundation; either version 2 of the License, or (at your option)
34 * any later version.
35 *
36 */
37
38#include <crypto/internal/hash.h>
39#include <linux/init.h>
40#include <linux/module.h>
41#include <linux/string.h>
42#include <linux/kernel.h>
43#include <linux/crc32.h>
44
45#define CHKSUM_BLOCK_SIZE 1
46#define CHKSUM_DIGEST_SIZE 4
47
48struct chksum_ctx {
49 u32 key;
50};
51
52struct chksum_desc_ctx {
53 u32 crc;
54};
55
56/*
57 * Steps through buffer one byte at at time, calculates reflected
58 * crc using table.
59 */
60
61static int chksum_init(struct shash_desc *desc)
62{
63 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
64 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
65
66 ctx->crc = mctx->key;
67
68 return 0;
69}
70
71/*
72 * Setting the seed allows arbitrary accumulators and flexible XOR policy
73 * If your algorithm starts with ~0, then XOR with ~0 before you set
74 * the seed.
75 */
76static int chksum_setkey(struct crypto_shash *tfm, const u8 *key,
77 unsigned int keylen)
78{
79 struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
80
81 if (keylen != sizeof(mctx->key)) {
82 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
83 return -EINVAL;
84 }
85 mctx->key = le32_to_cpu(*(__le32 *)key);
86 return 0;
87}
88
89static int chksum_update(struct shash_desc *desc, const u8 *data,
90 unsigned int length)
91{
92 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
93
94 ctx->crc = __crc32c_le(ctx->crc, data, length);
95 return 0;
96}
97
98static int chksum_final(struct shash_desc *desc, u8 *out)
99{
100 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
101
102 *(__le32 *)out = ~cpu_to_le32p(&ctx->crc);
103 return 0;
104}
105
106static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
107{
108 *(__le32 *)out = ~cpu_to_le32(__crc32c_le(*crcp, data, len));
109 return 0;
110}
111
112static int chksum_finup(struct shash_desc *desc, const u8 *data,
113 unsigned int len, u8 *out)
114{
115 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
116
117 return __chksum_finup(&ctx->crc, data, len, out);
118}
119
120static int chksum_digest(struct shash_desc *desc, const u8 *data,
121 unsigned int length, u8 *out)
122{
123 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
124
125 return __chksum_finup(&mctx->key, data, length, out);
126}
127
128static int crc32c_cra_init(struct crypto_tfm *tfm)
129{
130 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
131
132 mctx->key = ~0;
133 return 0;
134}
135
136static struct shash_alg alg = {
137 .digestsize = CHKSUM_DIGEST_SIZE,
138 .setkey = chksum_setkey,
139 .init = chksum_init,
140 .update = chksum_update,
141 .final = chksum_final,
142 .finup = chksum_finup,
143 .digest = chksum_digest,
144 .descsize = sizeof(struct chksum_desc_ctx),
145 .base = {
146 .cra_name = "crc32c",
147 .cra_driver_name = "crc32c-generic",
148 .cra_priority = 100,
149 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
150 .cra_blocksize = CHKSUM_BLOCK_SIZE,
151 .cra_alignmask = 3,
152 .cra_ctxsize = sizeof(struct chksum_ctx),
153 .cra_module = THIS_MODULE,
154 .cra_init = crc32c_cra_init,
155 }
156};
157
158static int __init crc32c_mod_init(void)
159{
160 return crypto_register_shash(&alg);
161}
162
163static void __exit crc32c_mod_fini(void)
164{
165 crypto_unregister_shash(&alg);
166}
167
168module_init(crc32c_mod_init);
169module_exit(crc32c_mod_fini);
170
171MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
172MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
173MODULE_LICENSE("GPL");
174MODULE_ALIAS_CRYPTO("crc32c");
175MODULE_ALIAS_CRYPTO("crc32c-generic");