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 #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
  15 typedef void (sha256_block_fn)(struct sha256_state *sst, u8 const *src,
  16                                int blocks);
  17
  18 static 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
  35 static 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
  52 static 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
  90 static 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
 113 static 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 }