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         return sha224_init(sctx);
  26 }
  27
  28 static 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
  35 static 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
  73 static 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
  96 static 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 */