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	return sha224_init(sctx);
 26}
 27
 28static inline int sha256_base_init(struct shash_desc *desc)
 29{
 30	struct sha256_state *sctx = shash_desc_ctx(desc);
 31
 32	return sha256_init(sctx);
 33}
 34
 35static inline int sha256_base_do_update(struct shash_desc *desc,
 36					const u8 *data,
 37					unsigned int len,
 38					sha256_block_fn *block_fn)
 39{
 40	struct sha256_state *sctx = shash_desc_ctx(desc);
 41	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 42
 43	sctx->count += len;
 44
 45	if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
 46		int blocks;
 47
 48		if (partial) {
 49			int p = SHA256_BLOCK_SIZE - partial;
 50
 51			memcpy(sctx->buf + partial, data, p);
 52			data += p;
 53			len -= p;
 54
 55			block_fn(sctx, sctx->buf, 1);
 56		}
 57
 58		blocks = len / SHA256_BLOCK_SIZE;
 59		len %= SHA256_BLOCK_SIZE;
 60
 61		if (blocks) {
 62			block_fn(sctx, data, blocks);
 63			data += blocks * SHA256_BLOCK_SIZE;
 64		}
 65		partial = 0;
 66	}
 67	if (len)
 68		memcpy(sctx->buf + partial, data, len);
 69
 70	return 0;
 71}
 72
 73static inline int sha256_base_do_finalize(struct shash_desc *desc,
 74					  sha256_block_fn *block_fn)
 75{
 76	const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
 77	struct sha256_state *sctx = shash_desc_ctx(desc);
 78	__be64 *bits = (__be64 *)(sctx->buf + bit_offset);
 79	unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 80
 81	sctx->buf[partial++] = 0x80;
 82	if (partial > bit_offset) {
 83		memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 84		partial = 0;
 85
 86		block_fn(sctx, sctx->buf, 1);
 87	}
 88
 89	memset(sctx->buf + partial, 0x0, bit_offset - partial);
 90	*bits = cpu_to_be64(sctx->count << 3);
 91	block_fn(sctx, sctx->buf, 1);
 92
 93	return 0;
 94}
 95
 96static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 97{
 98	unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
 99	struct sha256_state *sctx = shash_desc_ctx(desc);
100	__be32 *digest = (__be32 *)out;
101	int i;
102
103	for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
104		put_unaligned_be32(sctx->state[i], digest++);
105
106	*sctx = (struct sha256_state){};
107	return 0;
108}
109
110#endif /* _CRYPTO_SHA256_BASE_H */