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 <asm/byteorder.h>
 12#include <asm/unaligned.h>
 13#include <crypto/internal/hash.h>
 14#include <crypto/sha2.h>
 15#include <linux/string.h>
 16#include <linux/types.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	sha224_init(sctx);
 26	return 0;
 27}
 28
 29static inline int sha256_base_init(struct shash_desc *desc)
 30{
 31	struct sha256_state *sctx = shash_desc_ctx(desc);
 32
 33	sha256_init(sctx);
 34	return 0;
 35}
 36
 37static inline int lib_sha256_base_do_update(struct sha256_state *sctx,
 38					    const u8 *data,
 39					    unsigned int len,
 40					    sha256_block_fn *block_fn)
 41{
 42	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 43
 44	sctx->count += len;
 45
 46	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
 47		int blocks;
 48
 49		if (partial) {
 50			int p = SHA256_BLOCK_SIZE - partial;
 51
 52			memcpy(sctx->buf + partial, data, p);
 53			data += p;
 54			len -= p;
 55
 56			block_fn(sctx, sctx->buf, 1);
 57		}
 58
 59		blocks = len / SHA256_BLOCK_SIZE;
 60		len %= SHA256_BLOCK_SIZE;
 61
 62		if (blocks) {
 63			block_fn(sctx, data, blocks);
 64			data += blocks * SHA256_BLOCK_SIZE;
 65		}
 66		partial = 0;
 67	}
 68	if (len)
 69		memcpy(sctx->buf + partial, data, len);
 70
 71	return 0;
 72}
 73
 74static inline int sha256_base_do_update(struct shash_desc *desc,
 75					const u8 *data,
 76					unsigned int len,
 77					sha256_block_fn *block_fn)
 78{
 79	struct sha256_state *sctx = shash_desc_ctx(desc);
 80
 81	return lib_sha256_base_do_update(sctx, data, len, block_fn);
 82}
 83
 84static inline int lib_sha256_base_do_finalize(struct sha256_state *sctx,
 85					      sha256_block_fn *block_fn)
 86{
 87	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
 88	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);
 89	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 90
 91	sctx->buf[partial++] = 0x80;
 92	if (partial > bit_offset) {
 93		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 94		partial = 0;
 95
 96		block_fn(sctx, sctx->buf, 1);
 97	}
 98
 99	memset(sctx->buf + partial, 0x0, bit_offset - partial);
100	*bits = cpu_to_be64(sctx->count << 3);
101	block_fn(sctx, sctx->buf, 1);
102
103	return 0;
104}
105
106static inline int sha256_base_do_finalize(struct shash_desc *desc,
107					  sha256_block_fn *block_fn)
108{
109	struct sha256_state *sctx = shash_desc_ctx(desc);
110
111	return lib_sha256_base_do_finalize(sctx, block_fn);
112}
113
114static inline int lib_sha256_base_finish(struct sha256_state *sctx, u8 *out,
115					 unsigned int digest_size)
116{
117	__be32 *digest = (__be32 *)out;
118	int i;
119
120	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
121		put_unaligned_be32(sctx->state[i], digest++);
122
123	memzero_explicit(sctx, sizeof(*sctx));
124	return 0;
125}
126
127static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
128{
129	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
130	struct sha256_state *sctx = shash_desc_ctx(desc);
131
132	return lib_sha256_base_finish(sctx, out, digest_size);
133}
134
135#endif /* _CRYPTO_SHA256_BASE_H */