1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2012 Xyratex Technology Limited
4 */
5
6/*
7 * This is crypto api shash wrappers to crc32_le.
8 */
9
10#include <asm/unaligned.h>
11#include <linux/crc32.h>
12#include <crypto/internal/hash.h>
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/string.h>
16#include <linux/kernel.h>
17
18#define CHKSUM_BLOCK_SIZE	1
19#define CHKSUM_DIGEST_SIZE	4
20
21/** No default init with ~0 */
22static int crc32_cra_init(struct crypto_tfm *tfm)
23{
24	u32 *key = crypto_tfm_ctx(tfm);
25
26	*key = 0;
27
28	return 0;
29}
30
31/*
32 * Setting the seed allows arbitrary accumulators and flexible XOR policy
33 * If your algorithm starts with ~0, then XOR with ~0 before you set
34 * the seed.
35 */
36static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
37			unsigned int keylen)
38{
39	u32 *mctx = crypto_shash_ctx(hash);
40
41	if (keylen != sizeof(u32))
42		return -EINVAL;
43	*mctx = get_unaligned_le32(key);
44	return 0;
45}
46
47static int crc32_init(struct shash_desc *desc)
48{
49	u32 *mctx = crypto_shash_ctx(desc->tfm);
50	u32 *crcp = shash_desc_ctx(desc);
51
52	*crcp = *mctx;
53
54	return 0;
55}
56
57static int crc32_update(struct shash_desc *desc, const u8 *data,
58			unsigned int len)
59{
60	u32 *crcp = shash_desc_ctx(desc);
61
62	*crcp = crc32_le(*crcp, data, len);
63	return 0;
64}
65
66/* No final XOR 0xFFFFFFFF, like crc32_le */
67static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
68			 u8 *out)
69{
70	put_unaligned_le32(crc32_le(*crcp, data, len), out);
71	return 0;
72}
73
74static int crc32_finup(struct shash_desc *desc, const u8 *data,
75		       unsigned int len, u8 *out)
76{
77	return __crc32_finup(shash_desc_ctx(desc), data, len, out);
78}
79
80static int crc32_final(struct shash_desc *desc, u8 *out)
81{
82	u32 *crcp = shash_desc_ctx(desc);
83
84	put_unaligned_le32(*crcp, out);
85	return 0;
86}
87
88static int crc32_digest(struct shash_desc *desc, const u8 *data,
89			unsigned int len, u8 *out)
90{
91	return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len,
92			     out);
93}
94static struct shash_alg alg = {
95	.setkey		= crc32_setkey,
96	.init		= crc32_init,
97	.update		= crc32_update,
98	.final		= crc32_final,
99	.finup		= crc32_finup,
100	.digest		= crc32_digest,
101	.descsize	= sizeof(u32),
102	.digestsize	= CHKSUM_DIGEST_SIZE,
103	.base		= {
104		.cra_name		= "crc32",
105		.cra_driver_name	= "crc32-generic",
106		.cra_priority		= 100,
107		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
108		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
109		.cra_ctxsize		= sizeof(u32),
110		.cra_module		= THIS_MODULE,
111		.cra_init		= crc32_cra_init,
112	}
113};
114
115static int __init crc32_mod_init(void)
116{
117	return crypto_register_shash(&alg);
118}
119
120static void __exit crc32_mod_fini(void)
121{
122	crypto_unregister_shash(&alg);
123}
124
125subsys_initcall(crc32_mod_init);
126module_exit(crc32_mod_fini);
127
128MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
129MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
130MODULE_LICENSE("GPL");
131MODULE_ALIAS_CRYPTO("crc32");
132MODULE_ALIAS_CRYPTO("crc32-generic");
133