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 */
22 static 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 */
36 static 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
47 static 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
57 static 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 */
67 static 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
74 static 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
80 static 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
88 static 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 }
94 static 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
115 static int __init crc32_mod_init(void)
116 {
117 return crypto_register_shash(&alg);
118 }
119
120 static void __exit crc32_mod_fini(void)
121 {
122 crypto_unregister_shash(&alg);
123 }
124
125 subsys_initcall(crc32_mod_init);
126 module_exit(crc32_mod_fini);
127
128 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
129 MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32");
130 MODULE_LICENSE("GPL");
131 MODULE_ALIAS_CRYPTO("crc32");
132 MODULE_ALIAS_CRYPTO("crc32-generic");
133
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