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/sha2.h>
  13 #include <linux/crypto.h>
  14 #include <linux/module.h>
  15 #include <linux/string.h>
  16
  17 #include <asm/unaligned.h>
  18
  19 typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
  20                                int blocks);
  21
  22 static inline int sha224_base_init(struct shash_desc *desc)
  23 {
  24         struct sha256_state *sctx = shash_desc_ctx(desc);
  25
  26         sha224_init(sctx);
  27         return 0;
  28 }
  29
  30 static inline int sha256_base_init(struct shash_desc *desc)
  31 {
  32         struct sha256_state *sctx = shash_desc_ctx(desc);
  33
  34         sha256_init(sctx);
  35         return 0;
  36 }
  37
  38 static inline int sha256_base_do_update(struct shash_desc *desc,
  39                                         const u8 *data,
  40                                         unsigned int len,
  41                                         sha256_block_fn *block_fn)
  42 {
  43         struct sha256_state *sctx = shash_desc_ctx(desc);
  44         unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  45
  46         sctx->count += len;
  47
  48         if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
  49                 int blocks;
  50
  51                 if (partial) {
  52                         int p = SHA256_BLOCK_SIZE - partial;
  53
  54                         memcpy(sctx->buf + partial, data, p);
  55                         data += p;
  56                         len -= p;
  57
  58                         block_fn(sctx, sctx->buf, 1);
  59                 }
  60
  61                 blocks = len / SHA256_BLOCK_SIZE;
  62                 len %= SHA256_BLOCK_SIZE;
  63
  64                 if (blocks) {
  65                         block_fn(sctx, data, blocks);
  66                         data += blocks * SHA256_BLOCK_SIZE;
  67                 }
  68                 partial = 0;
  69         }
  70         if (len)
  71                 memcpy(sctx->buf + partial, data, len);
  72
  73         return 0;
  74 }
  75
  76 static inline int sha256_base_do_finalize(struct shash_desc *desc,
  77                                           sha256_block_fn *block_fn)
  78 {
  79         const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
  80         struct sha256_state *sctx = shash_desc_ctx(desc);
  81         __be64 *bits = (__be64 *)(sctx->buf + bit_offset);
  82         unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  83
  84         sctx->buf[partial++] = 0x80;
  85         if (partial > bit_offset) {
  86                 memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
  87                 partial = 0;
  88
  89                 block_fn(sctx, sctx->buf, 1);
  90         }
  91
  92         memset(sctx->buf + partial, 0x0, bit_offset - partial);
  93         *bits = cpu_to_be64(sctx->count << 3);
  94         block_fn(sctx, sctx->buf, 1);
  95
  96         return 0;
  97 }
  98
  99 static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 100 {
 101         unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
 102         struct sha256_state *sctx = shash_desc_ctx(desc);
 103         __be32 *digest = (__be32 *)out;
 104         int i;
 105
 106         for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
 107                 put_unaligned_be32(sctx->state[i], digest++);
 108
 109         memzero_explicit(sctx, sizeof(*sctx));
 110         return 0;
 111 }
 112
 113 #endif /* _CRYPTO_SHA256_BASE_H */