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 
18 typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
19 			       int blocks);
20 
sha224_base_init(struct shash_desc * desc)21 static 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 
sha256_base_init(struct shash_desc * desc)38 static 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 
sha256_base_do_update(struct shash_desc * desc,const u8 * data,unsigned int len,sha256_block_fn * block_fn)55 static 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 
sha256_base_do_finalize(struct shash_desc * desc,sha256_block_fn * block_fn)93 static 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 
sha256_base_finish(struct shash_desc * desc,u8 * out)116 static 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