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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_blocksize = CHKSUM_BLOCK_SIZE,
150 .cra_alignmask = 3,
151 .cra_ctxsize = sizeof(struct chksum_ctx),
152 .cra_module = THIS_MODULE,
153 .cra_init = crc32c_cra_init,
154 }
155};
156
157static int __init crc32c_mod_init(void)
158{
159 return crypto_register_shash(&alg);
160}
161
162static void __exit crc32c_mod_fini(void)
163{
164 crypto_unregister_shash(&alg);
165}
166
167module_init(crc32c_mod_init);
168module_exit(crc32c_mod_fini);
169
170MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
171MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
172MODULE_LICENSE("GPL");
173MODULE_ALIAS_CRYPTO("crc32c");
174MODULE_ALIAS_CRYPTO("crc32c-generic");
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 the
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 at 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 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
79 return -EINVAL;
80 }
81 mctx->key = get_unaligned_le32(key);
82 return 0;
83}
84
85static int chksum_update(struct shash_desc *desc, const u8 *data,
86 unsigned int length)
87{
88 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
89
90 ctx->crc = __crc32c_le(ctx->crc, data, length);
91 return 0;
92}
93
94static int chksum_final(struct shash_desc *desc, u8 *out)
95{
96 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
97
98 put_unaligned_le32(~ctx->crc, out);
99 return 0;
100}
101
102static int __chksum_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out)
103{
104 put_unaligned_le32(~__crc32c_le(*crcp, data, len), out);
105 return 0;
106}
107
108static int chksum_finup(struct shash_desc *desc, const u8 *data,
109 unsigned int len, u8 *out)
110{
111 struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
112
113 return __chksum_finup(&ctx->crc, data, len, out);
114}
115
116static int chksum_digest(struct shash_desc *desc, const u8 *data,
117 unsigned int length, u8 *out)
118{
119 struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
120
121 return __chksum_finup(&mctx->key, data, length, out);
122}
123
124static int crc32c_cra_init(struct crypto_tfm *tfm)
125{
126 struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
127
128 mctx->key = ~0;
129 return 0;
130}
131
132static struct shash_alg alg = {
133 .digestsize = CHKSUM_DIGEST_SIZE,
134 .setkey = chksum_setkey,
135 .init = chksum_init,
136 .update = chksum_update,
137 .final = chksum_final,
138 .finup = chksum_finup,
139 .digest = chksum_digest,
140 .descsize = sizeof(struct chksum_desc_ctx),
141 .base = {
142 .cra_name = "crc32c",
143 .cra_driver_name = "crc32c-generic",
144 .cra_priority = 100,
145 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
146 .cra_blocksize = CHKSUM_BLOCK_SIZE,
147 .cra_ctxsize = sizeof(struct chksum_ctx),
148 .cra_module = THIS_MODULE,
149 .cra_init = crc32c_cra_init,
150 }
151};
152
153static int __init crc32c_mod_init(void)
154{
155 return crypto_register_shash(&alg);
156}
157
158static void __exit crc32c_mod_fini(void)
159{
160 crypto_unregister_shash(&alg);
161}
162
163subsys_initcall(crc32c_mod_init);
164module_exit(crc32c_mod_fini);
165
166MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
167MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations wrapper for lib/crc32c");
168MODULE_LICENSE("GPL");
169MODULE_ALIAS_CRYPTO("crc32c");
170MODULE_ALIAS_CRYPTO("crc32c-generic");