include/crypto/sha256_base.h

   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
  18 typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
  19                                int blocks);
  20
  21 static 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
  29 static 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
  37 static 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
  75 static 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
  98 static 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 */