LXR linux/include/crypto/sha256

   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#include <crypto/internal/hash.h>
   9#include <crypto/sha.h>
  10#include <linux/crypto.h>
  11#include <linux/module.h>
  12
  13#include <asm/unaligned.h>
  14
  15typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
  16                               int blocks);
  17
  18static inline int sha224_base_init(struct shash_desc *desc)
  19{
  20        struct sha256_state *sctx = shash_desc_ctx(desc);
  21
  22        sctx->state[0] = SHA224_H0;
  23        sctx->state[1] = SHA224_H1;
  24        sctx->state[2] = SHA224_H2;
  25        sctx->state[3] = SHA224_H3;
  26        sctx->state[4] = SHA224_H4;
  27        sctx->state[5] = SHA224_H5;
  28        sctx->state[6] = SHA224_H6;
  29        sctx->state[7] = SHA224_H7;
  30        sctx->count = 0;
  31
  32        return 0;
  33}
  34
  35static inline int sha256_base_init(struct shash_desc *desc)
  36{
  37        struct sha256_state *sctx = shash_desc_ctx(desc);
  38
  39        sctx->state[0] = SHA256_H0;
  40        sctx->state[1] = SHA256_H1;
  41        sctx->state[2] = SHA256_H2;
  42        sctx->state[3] = SHA256_H3;
  43        sctx->state[4] = SHA256_H4;
  44        sctx->state[5] = SHA256_H5;
  45        sctx->state[6] = SHA256_H6;
  46        sctx->state[7] = SHA256_H7;
  47        sctx->count = 0;
  48
  49        return 0;
  50}
  51
  52static inline int sha256_base_do_update(struct shash_desc *desc,
  53                                        const u8 *data,
  54                                        unsigned int len,
  55                                        sha256_block_fn *block_fn)
  56{
  57        struct sha256_state *sctx = shash_desc_ctx(desc);
  58        unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  59
  60        sctx->count += len;
  61
  62        if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
  63                int blocks;
  64
  65                if (partial) {
  66                        int p = SHA256_BLOCK_SIZE - partial;
  67
  68                        memcpy(sctx->buf + partial, data, p);
  69                        data += p;
  70                        len -= p;
  71
  72                        block_fn(sctx, sctx->buf, 1);
  73                }
  74
  75                blocks = len / SHA256_BLOCK_SIZE;
  76                len %= SHA256_BLOCK_SIZE;
  77
  78                if (blocks) {
  79                        block_fn(sctx, data, blocks);
  80                        data += blocks * SHA256_BLOCK_SIZE;
  81                }
  82                partial = 0;
  83        }
  84        if (len)
  85                memcpy(sctx->buf + partial, data, len);
  86
  87        return 0;
  88}
  89
  90static inline int sha256_base_do_finalize(struct shash_desc *desc,
  91                                          sha256_block_fn *block_fn)
  92{
  93        const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
  94        struct sha256_state *sctx = shash_desc_ctx(desc);
  95        __be64 *bits = (__be64 *)(sctx->buf + bit_offset);
  96        unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  97
  98        sctx->buf[partial++] = 0x80;
  99        if (partial > bit_offset) {
 100                memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 101                partial = 0;
 102
 103                block_fn(sctx, sctx->buf, 1);
 104        }
 105
 106        memset(sctx->buf + partial, 0x0, bit_offset - partial);
 107        *bits = cpu_to_be64(sctx->count << 3);
 108        block_fn(sctx, sctx->buf, 1);
 109
 110        return 0;
 111}
 112
 113static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 114{
 115        unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
 116        struct sha256_state *sctx = shash_desc_ctx(desc);
 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        *sctx = (struct sha256_state){};
 124        return 0;
 125}
 126