include/crypto/sha1_base.h

   1 /*
   2  * sha1_base.h - core logic for SHA-1 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 (sha1_block_fn)(struct sha1_state *sst, u8 const *src, int blocks);
  19
  20 static inline int sha1_base_init(struct shash_desc *desc)
  21 {
  22         struct sha1_state *sctx = shash_desc_ctx(desc);
  23
  24         sctx->state[0] = SHA1_H0;
  25         sctx->state[1] = SHA1_H1;
  26         sctx->state[2] = SHA1_H2;
  27         sctx->state[3] = SHA1_H3;
  28         sctx->state[4] = SHA1_H4;
  29         sctx->count = 0;
  30
  31         return 0;
  32 }
  33
  34 static inline int sha1_base_do_update(struct shash_desc *desc,
  35                                       const u8 *data,
  36                                       unsigned int len,
  37                                       sha1_block_fn *block_fn)
  38 {
  39         struct sha1_state *sctx = shash_desc_ctx(desc);
  40         unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
  41
  42         sctx->count += len;
  43
  44         if (unlikely((partial + len) >= SHA1_BLOCK_SIZE)) {
  45                 int blocks;
  46
  47                 if (partial) {
  48                         int p = SHA1_BLOCK_SIZE - partial;
  49
  50                         memcpy(sctx->buffer + partial, data, p);
  51                         data += p;
  52                         len -= p;
  53
  54                         block_fn(sctx, sctx->buffer, 1);
  55                 }
  56
  57                 blocks = len / SHA1_BLOCK_SIZE;
  58                 len %= SHA1_BLOCK_SIZE;
  59
  60                 if (blocks) {
  61                         block_fn(sctx, data, blocks);
  62                         data += blocks * SHA1_BLOCK_SIZE;
  63                 }
  64                 partial = 0;
  65         }
  66         if (len)
  67                 memcpy(sctx->buffer + partial, data, len);
  68
  69         return 0;
  70 }
  71
  72 static inline int sha1_base_do_finalize(struct shash_desc *desc,
  73                                         sha1_block_fn *block_fn)
  74 {
  75         const int bit_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
  76         struct sha1_state *sctx = shash_desc_ctx(desc);
  77         __be64 *bits = (__be64 *)(sctx->buffer + bit_offset);
  78         unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
  79
  80         sctx->buffer[partial++] = 0x80;
  81         if (partial > bit_offset) {
  82                 memset(sctx->buffer + partial, 0x0, SHA1_BLOCK_SIZE - partial);
  83                 partial = 0;
  84
  85                 block_fn(sctx, sctx->buffer, 1);
  86         }
  87
  88         memset(sctx->buffer + partial, 0x0, bit_offset - partial);
  89         *bits = cpu_to_be64(sctx->count << 3);
  90         block_fn(sctx, sctx->buffer, 1);
  91
  92         return 0;
  93 }
  94
  95 static inline int sha1_base_finish(struct shash_desc *desc, u8 *out)
  96 {
  97         struct sha1_state *sctx = shash_desc_ctx(desc);
  98         __be32 *digest = (__be32 *)out;
  99         int i;
 100
 101         for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(__be32); i++)
 102                 put_unaligned_be32(sctx->state[i], digest++);
 103
 104         *sctx = (struct sha1_state){};
 105         return 0;
 106 }