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 <linux/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_base(*crcp, data, len);
 63	return 0;
 64}
 65
 66static int crc32_update_arch(struct shash_desc *desc, const u8 *data,
 67			     unsigned int len)
 68{
 69	u32 *crcp = shash_desc_ctx(desc);
 70
 71	*crcp = crc32_le(*crcp, data, len);
 72	return 0;
 73}
 74
 75/* No final XOR 0xFFFFFFFF, like crc32_le */
 76static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len,
 77			 u8 *out)
 78{
 79	put_unaligned_le32(crc32_le_base(*crcp, data, len), out);
 80	return 0;
 81}
 82
 83static int __crc32_finup_arch(u32 *crcp, const u8 *data, unsigned int len,
 84			      u8 *out)
 85{
 86	put_unaligned_le32(crc32_le(*crcp, data, len), out);
 87	return 0;
 88}
 89
 90static int crc32_finup(struct shash_desc *desc, const u8 *data,
 91		       unsigned int len, u8 *out)
 92{
 93	return __crc32_finup(shash_desc_ctx(desc), data, len, out);
 94}
 95
 96static int crc32_finup_arch(struct shash_desc *desc, const u8 *data,
 97		       unsigned int len, u8 *out)
 98{
 99	return __crc32_finup_arch(shash_desc_ctx(desc), data, len, out);
100}
101
102static int crc32_final(struct shash_desc *desc, u8 *out)
103{
104	u32 *crcp = shash_desc_ctx(desc);
105
106	put_unaligned_le32(*crcp, out);
107	return 0;
108}
109
110static int crc32_digest(struct shash_desc *desc, const u8 *data,
111			unsigned int len, u8 *out)
112{
113	return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out);
114}
115
116static int crc32_digest_arch(struct shash_desc *desc, const u8 *data,
117			     unsigned int len, u8 *out)
118{
119	return __crc32_finup_arch(crypto_shash_ctx(desc->tfm), data, len, out);
120}
121
122static struct shash_alg algs[] = {{
123	.setkey			= crc32_setkey,
124	.init			= crc32_init,
125	.update			= crc32_update,
126	.final			= crc32_final,
127	.finup			= crc32_finup,
128	.digest			= crc32_digest,
129	.descsize		= sizeof(u32),
130	.digestsize		= CHKSUM_DIGEST_SIZE,
131
132	.base.cra_name		= "crc32",
133	.base.cra_driver_name	= "crc32-generic",
134	.base.cra_priority	= 100,
135	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
136	.base.cra_blocksize	= CHKSUM_BLOCK_SIZE,
137	.base.cra_ctxsize	= sizeof(u32),
138	.base.cra_module	= THIS_MODULE,
139	.base.cra_init		= crc32_cra_init,
140}, {
141	.setkey			= crc32_setkey,
142	.init			= crc32_init,
143	.update			= crc32_update_arch,
144	.final			= crc32_final,
145	.finup			= crc32_finup_arch,
146	.digest			= crc32_digest_arch,
147	.descsize		= sizeof(u32),
148	.digestsize		= CHKSUM_DIGEST_SIZE,
149
150	.base.cra_name		= "crc32",
151	.base.cra_driver_name	= "crc32-" __stringify(ARCH),
152	.base.cra_priority	= 150,
153	.base.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
154	.base.cra_blocksize	= CHKSUM_BLOCK_SIZE,
155	.base.cra_ctxsize	= sizeof(u32),
156	.base.cra_module	= THIS_MODULE,
157	.base.cra_init		= crc32_cra_init,
158}};
159
160static int __init crc32_mod_init(void)
161{
162	/* register the arch flavor only if it differs from the generic one */
163	return crypto_register_shashes(algs, 1 + (&crc32_le != &crc32_le_base));
164}
165
166static void __exit crc32_mod_fini(void)
167{
168	crypto_unregister_shashes(algs, 1 + (&crc32_le != &crc32_le_base));
169}
170
171subsys_initcall(crc32_mod_init);
172module_exit(crc32_mod_fini);
173
174MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
175MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
176MODULE_LICENSE("GPL");
177MODULE_ALIAS_CRYPTO("crc32");
178MODULE_ALIAS_CRYPTO("crc32-generic");