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/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	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 sha256_base_do_update(struct shash_desc *desc,
 38					const u8 *data,
 39					unsigned int len,
 40					sha256_block_fn *block_fn)
 41{
 42	struct sha256_state *sctx = shash_desc_ctx(desc);
 43	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 44
 45	sctx->count += len;
 46
 47	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
 48		int blocks;
 49
 50		if (partial) {
 51			int p = SHA256_BLOCK_SIZE - partial;
 52
 53			memcpy(sctx->buf + partial, data, p);
 54			data += p;
 55			len -= p;
 56
 57			block_fn(sctx, sctx->buf, 1);
 58		}
 59
 60		blocks = len / SHA256_BLOCK_SIZE;
 61		len %= SHA256_BLOCK_SIZE;
 62
 63		if (blocks) {
 64			block_fn(sctx, data, blocks);
 65			data += blocks * SHA256_BLOCK_SIZE;
 66		}
 67		partial = 0;
 68	}
 69	if (len)
 70		memcpy(sctx->buf + partial, data, len);
 71
 72	return 0;
 73}
 74
 75static inline int sha256_base_do_finalize(struct shash_desc *desc,
 76					  sha256_block_fn *block_fn)
 77{
 78	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
 79	struct sha256_state *sctx = shash_desc_ctx(desc);
 80	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);
 81	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 82
 83	sctx->buf[partial++] = 0x80;
 84	if (partial > bit_offset) {
 85		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 86		partial = 0;
 87
 88		block_fn(sctx, sctx->buf, 1);
 89	}
 90
 91	memset(sctx->buf + partial, 0x0, bit_offset - partial);
 92	*bits = cpu_to_be64(sctx->count << 3);
 93	block_fn(sctx, sctx->buf, 1);
 94
 95	return 0;
 96}
 97
 98static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 99{
100	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
101	struct sha256_state *sctx = shash_desc_ctx(desc);
102	__be32 *digest = (__be32 *)out;
103	int i;
104
105	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
106		put_unaligned_be32(sctx->state[i], digest++);
107
108	*sctx = (struct sha256_state){};
109	return 0;
110}
111
112#endif /* _CRYPTO_SHA256_BASE_H */