include/crypto/sha256_base.h

   1 /*
   2  * sha256_base.h - core logic for SHA-256 implementations
   3  *
   4  * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  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         sctx->state[0] = SHA224_H0;
  26         sctx->state[1] = SHA224_H1;
  27         sctx->state[2] = SHA224_H2;
  28         sctx->state[3] = SHA224_H3;
  29         sctx->state[4] = SHA224_H4;
  30         sctx->state[5] = SHA224_H5;
  31         sctx->state[6] = SHA224_H6;
  32         sctx->state[7] = SHA224_H7;
  33         sctx->count = 0;
  34
  35         return 0;
  36 }
  37
  38 static inline int sha256_base_init(struct shash_desc *desc)
  39 {
  40         struct sha256_state *sctx = shash_desc_ctx(desc);
  41
  42         sctx->state[0] = SHA256_H0;
  43         sctx->state[1] = SHA256_H1;
  44         sctx->state[2] = SHA256_H2;
  45         sctx->state[3] = SHA256_H3;
  46         sctx->state[4] = SHA256_H4;
  47         sctx->state[5] = SHA256_H5;
  48         sctx->state[6] = SHA256_H6;
  49         sctx->state[7] = SHA256_H7;
  50         sctx->count = 0;
  51
  52         return 0;
  53 }
  54
  55 static inline int sha256_base_do_update(struct shash_desc *desc,
  56                                         const u8 *data,
  57                                         unsigned int len,
  58                                         sha256_block_fn *block_fn)
  59 {
  60         struct sha256_state *sctx = shash_desc_ctx(desc);
  61         unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
  62
  63         sctx->count += len;
  64
  65         if (unlikely((partial + len) >= SHA256_BLOCK_SIZE)) {
  66                 int blocks;
  67
  68                 if (partial) {
  69                         int p = SHA256_BLOCK_SIZE - partial;
  70
  71                         memcpy(sctx->buf + partial, data, p);
  72                         data += p;
  73                         len -= p;
  74
  75                         block_fn(sctx, sctx->buf, 1);
  76                 }
  77
  78                 blocks = len / SHA256_BLOCK_SIZE;
  79                 len %= SHA256_BLOCK_SIZE;
  80
  81                 if (blocks) {
  82                         block_fn(sctx, data, blocks);
  83                         data += blocks * SHA256_BLOCK_SIZE;
  84                 }
  85                 partial = 0;
  86         }
  87         if (len)
  88                 memcpy(sctx->buf + partial, data, len);
  89
  90         return 0;
  91 }
  92
  93 static inline int sha256_base_do_finalize(struct shash_desc *desc,
  94                                           sha256_block_fn *block_fn)
  95 {
  96         const int bit_offset = SHA256_BLOCK_SIZE - sizeof(__be64);
  97         struct sha256_state *sctx = shash_desc_ctx(desc);
  98         __be64 *bits = (__be64 *)(sctx->buf + bit_offset);
  99         unsigned int partial = sctx->count % SHA256_BLOCK_SIZE;
 100
 101         sctx->buf[partial++] = 0x80;
 102         if (partial > bit_offset) {
 103                 memset(sctx->buf + partial, 0x0, SHA256_BLOCK_SIZE - partial);
 104                 partial = 0;
 105
 106                 block_fn(sctx, sctx->buf, 1);
 107         }
 108
 109         memset(sctx->buf + partial, 0x0, bit_offset - partial);
 110         *bits = cpu_to_be64(sctx->count << 3);
 111         block_fn(sctx, sctx->buf, 1);
 112
 113         return 0;
 114 }
 115
 116 static inline int sha256_base_finish(struct shash_desc *desc, u8 *out)
 117 {
 118         unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
 119         struct sha256_state *sctx = shash_desc_ctx(desc);
 120         __be32 *digest = (__be32 *)out;
 121         int i;
 122
 123         for (i = 0; digest_size > 0; i++, digest_size -= sizeof(__be32))
 124                 put_unaligned_be32(sctx->state[i], digest++);
 125
 126         *sctx = (struct sha256_state){};
 127         return 0;
 128 }