1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * sha256_base.h - core logic for SHA-256 implementations
4  *
5  * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
6  */
7 
8 #ifndef _CRYPTO_SHA256_BASE_H
9 #define _CRYPTO_SHA256_BASE_H
10 
11 #include <crypto/internal/hash.h>
12 #include <crypto/sha2.h>
13 #include <linux/crypto.h>
14 #include <linux/module.h>
15 #include <linux/string.h>
16 
17 #include <asm/unaligned.h>
18 
19 typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
20 			       int blocks);
21 
sha224_base_init(struct shash_desc * desc)22 static inline int sha224_base_init(struct shash_desc *desc)
23 {
24 	struct sha256_state *sctx = shash_desc_ctx(desc);
25 
26 	sha224_init(sctx);
27 	return 0;
28 }
29 
sha256_base_init(struct shash_desc * desc)30 static inline int sha256_base_init(struct shash_desc *desc)
31 {
32 	struct sha256_state *sctx = shash_desc_ctx(desc);
33 
34 	sha256_init(sctx);
35 	return 0;
36 }
37 
sha256_base_do_update(struct shash_desc * desc,const u8 * data,unsigned int len,sha256_block_fn * block_fn)38 static inline int sha256_base_do_update(struct shash_desc *desc,
39 					const u8 *data,
40 					unsigned int len,
41 					sha256_block_fn *block_fn)
42 {
43 	struct sha256_state *sctx = shash_desc_ctx(desc);
44 	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
45 
46 	sctx->count += len;
47 
48 	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
49 		int blocks;
50 
51 		if (partial) {
52 			int p = SHA256_BLOCK_SIZE - partial;
53 
54 			memcpy(sctx->buf + partial, data, p);
55 			data += p;
56 			len -= p;
57 
58 			block_fn(sctx, sctx->buf, 1);
59 		}
60 
61 		blocks = len / SHA256_BLOCK_SIZE;
62 		len %= SHA256_BLOCK_SIZE;
63 
64 		if (blocks) {
65 			block_fn(sctx, data, blocks);
66 			data += blocks * SHA256_BLOCK_SIZE;
67 		}
68 		partial = 0;
69 	}
70 	if (len)
71 		memcpy(sctx->buf + partial, data, len);
72 
73 	return 0;
74 }
75 
sha256_base_do_finalize(struct shash_desc * desc,sha256_block_fn * block_fn)76 static inline int sha256_base_do_finalize(struct shash_desc *desc,
77 					  sha256_block_fn *block_fn)
78 {
79 	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
80 	struct sha256_state *sctx = shash_desc_ctx(desc);
81 	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);
82 	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
83 
84 	sctx->buf[partial++] = 0x80;
85 	if (partial > bit_offset) {
86 		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
87 		partial = 0;
88 
89 		block_fn(sctx, sctx->buf, 1);
90 	}
91 
92 	memset(sctx->buf + partial, 0x0, bit_offset - partial);
93 	*bits = cpu_to_be64(sctx->count << 3);
94 	block_fn(sctx, sctx->buf, 1);
95 
96 	return 0;
97 }
98 
sha256_base_finish(struct shash_desc * desc,u8 * out)99 static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
100 {
101 	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
102 	struct sha256_state *sctx = shash_desc_ctx(desc);
103 	__be32 *digest = (__be32 *)out;
104 	int i;
105 
106 	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
107 		put_unaligned_be32(sctx->state[i], digest++);
108 
109 	memzero_explicit(sctx, sizeof(*sctx));
110 	return 0;
111 }
112 
113 #endif /* _CRYPTO_SHA256_BASE_H */
114