1/*
2 * sha256_base.h - core logic for SHA-256 implementations
3 *
4 * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <crypto/internal/hash.h>
12#include <crypto/sha.h>
13#include <linux/crypto.h>
14#include <linux/module.h>
15
16#include <asm/unaligned.h>
17
18typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
19			       int blocks);
20
21static inline int sha224_base_init(struct shash_desc *desc)
22{
23	struct sha256_state *sctx = shash_desc_ctx(desc);
24
25	sctx->state[0] = SHA224_H0;
26	sctx->state[1] = SHA224_H1;
27	sctx->state[2] = SHA224_H2;
28	sctx->state[3] = SHA224_H3;
29	sctx->state[4] = SHA224_H4;
30	sctx->state[5] = SHA224_H5;
31	sctx->state[6] = SHA224_H6;
32	sctx->state[7] = SHA224_H7;
33	sctx->count = 0;
34
35	return 0;
36}
37
38static inline int sha256_base_init(struct shash_desc *desc)
39{
40	struct sha256_state *sctx = shash_desc_ctx(desc);
41
42	sctx->state[0] = SHA256_H0;
43	sctx->state[1] = SHA256_H1;
44	sctx->state[2] = SHA256_H2;
45	sctx->state[3] = SHA256_H3;
46	sctx->state[4] = SHA256_H4;
47	sctx->state[5] = SHA256_H5;
48	sctx->state[6] = SHA256_H6;
49	sctx->state[7] = SHA256_H7;
50	sctx->count = 0;
51
52	return 0;
53}
54
55static inline int sha256_base_do_update(struct shash_desc *desc,
56					const u8 *data,
57					unsigned int len,
58					sha256_block_fn *block_fn)
59{
60	struct sha256_state *sctx = shash_desc_ctx(desc);
61	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
62
63	sctx->count += len;
64
65	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
66		int blocks;
67
68		if (partial) {
69			int p = SHA256_BLOCK_SIZE - partial;
70
71			memcpy(sctx->buf + partial, data, p);
72			data += p;
73			len -= p;
74
75			block_fn(sctx, sctx->buf, 1);
76		}
77
78		blocks = len / SHA256_BLOCK_SIZE;
79		len %= SHA256_BLOCK_SIZE;
80
81		if (blocks) {
82			block_fn(sctx, data, blocks);
83			data += blocks * SHA256_BLOCK_SIZE;
84		}
85		partial = 0;
86	}
87	if (len)
88		memcpy(sctx->buf + partial, data, len);
89
90	return 0;
91}
92
93static inline int sha256_base_do_finalize(struct shash_desc *desc,
94					  sha256_block_fn *block_fn)
95{
96	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
97	struct sha256_state *sctx = shash_desc_ctx(desc);
98	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);
99	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
100
101	sctx->buf[partial++] = 0x80;
102	if (partial > bit_offset) {
103		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
104		partial = 0;
105
106		block_fn(sctx, sctx->buf, 1);
107	}
108
109	memset(sctx->buf + partial, 0x0, bit_offset - partial);
110	*bits = cpu_to_be64(sctx->count << 3);
111	block_fn(sctx, sctx->buf, 1);
112
113	return 0;
114}
115
116static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
117{
118	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
119	struct sha256_state *sctx = shash_desc_ctx(desc);
120	__be32 *digest = (__be32 *)out;
121	int i;
122
123	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
124		put_unaligned_be32(sctx->state[i], digest++);
125
126	*sctx = (struct sha256_state){};
127	return 0;
128}
129