crypto/digest.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * Digest operations.
   5  *
   6  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2 of the License, or (at your option)
  11  * any later version.
  12  *
  13  */
  14 #include <linux/crypto.h>
  15 #include <linux/mm.h>
  16 #include <linux/errno.h>
  17 #include <linux/highmem.h>
  18 #include <asm/scatterlist.h>
  19 #include "internal.h"
  20
  21 static void init(struct crypto_tfm *tfm)
  22 {
  23         tfm->__crt_alg->cra_digest.dia_init(crypto_tfm_ctx(tfm));
  24 }
  25
  26 static void update(struct crypto_tfm *tfm,
  27                    struct scatterlist *sg, unsigned int nsg)
  28 {
  29         unsigned int i;
  30
  31         for (i = 0; i < nsg; i++) {
  32
  33                 struct page *pg = sg[i].page;
  34                 unsigned int offset = sg[i].offset;
  35                 unsigned int l = sg[i].length;
  36
  37                 do {
  38                         unsigned int bytes_from_page = min(l, ((unsigned int)
  39                                                            (PAGE_SIZE)) -
  40                                                            offset);
  41                         char *p = crypto_kmap(pg, 0) + offset;
  42
  43                         tfm->__crt_alg->cra_digest.dia_update
  44                                         (crypto_tfm_ctx(tfm), p,
  45                                          bytes_from_page);
  46                         crypto_kunmap(p, 0);
  47                         crypto_yield(tfm);
  48                         offset = 0;
  49                         pg++;
  50                         l -= bytes_from_page;
  51                 } while (l > 0);
  52         }
  53 }
  54
  55 static void final(struct crypto_tfm *tfm, u8 *out)
  56 {
  57         tfm->__crt_alg->cra_digest.dia_final(crypto_tfm_ctx(tfm), out);
  58 }
  59
  60 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  61 {
  62         u32 flags;
  63         if (tfm->__crt_alg->cra_digest.dia_setkey == NULL)
  64                 return -ENOSYS;
  65         return tfm->__crt_alg->cra_digest.dia_setkey(crypto_tfm_ctx(tfm),
  66                                                      key, keylen, &flags);
  67 }
  68
  69 static void digest(struct crypto_tfm *tfm,
  70                    struct scatterlist *sg, unsigned int nsg, u8 *out)
  71 {
  72         unsigned int i;
  73
  74         tfm->crt_digest.dit_init(tfm);
  75
  76         for (i = 0; i < nsg; i++) {
  77                 char *p = crypto_kmap(sg[i].page, 0) + sg[i].offset;
  78                 tfm->__crt_alg->cra_digest.dia_update(crypto_tfm_ctx(tfm),
  79                                                       p, sg[i].length);
  80                 crypto_kunmap(p, 0);
  81                 crypto_yield(tfm);
  82         }
  83         crypto_digest_final(tfm, out);
  84 }
  85
  86 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
  87 {
  88         return flags ? -EINVAL : 0;
  89 }
  90
  91 int crypto_init_digest_ops(struct crypto_tfm *tfm)
  92 {
  93         struct digest_tfm *ops = &tfm->crt_digest;
  94
  95         ops->dit_init   = init;
  96         ops->dit_update = update;
  97         ops->dit_final  = final;
  98         ops->dit_digest = digest;
  99         ops->dit_setkey = setkey;
 100
 101         return crypto_alloc_hmac_block(tfm);
 102 }
 103
 104 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 105 {
 106         crypto_free_hmac_block(tfm);
 107 }