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(tfm);
  24 }
  25
  26 static void update(struct crypto_tfm *tfm,
  27                    struct scatterlist *sg, unsigned int nsg)
  28 {
  29         unsigned int i;
  30         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  31
  32         for (i = 0; i < nsg; i++) {
  33
  34                 struct page *pg = sg[i].page;
  35                 unsigned int offset = sg[i].offset;
  36                 unsigned int l = sg[i].length;
  37
  38                 do {
  39                         unsigned int bytes_from_page = min(l, ((unsigned int)
  40                                                            (PAGE_SIZE)) -
  41                                                            offset);
  42                         char *src = crypto_kmap(pg, 0);
  43                         char *p = src + offset;
  44
  45                         if (unlikely(offset & alignmask)) {
  46                                 unsigned int bytes =
  47                                         alignmask + 1 - (offset & alignmask);
  48                                 bytes = min(bytes, bytes_from_page);
  49                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  50                                                                       bytes);
  51                                 p += bytes;
  52                                 bytes_from_page -= bytes;
  53                                 l -= bytes;
  54                         }
  55                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  56                                                               bytes_from_page);
  57                         crypto_kunmap(src, 0);
  58                         crypto_yield(tfm);
  59                         offset = 0;
  60                         pg++;
  61                         l -= bytes_from_page;
  62                 } while (l > 0);
  63         }
  64 }
  65
  66 static void final(struct crypto_tfm *tfm, u8 *out)
  67 {
  68         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  69         if (unlikely((unsigned long)out & alignmask)) {
  70                 unsigned int size = crypto_tfm_alg_digestsize(tfm);
  71                 u8 buffer[size + alignmask];
  72                 u8 *dst = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  73                 tfm->__crt_alg->cra_digest.dia_final(tfm, dst);
  74                 memcpy(out, dst, size);
  75         } else
  76                 tfm->__crt_alg->cra_digest.dia_final(tfm, out);
  77 }
  78
  79 static int nosetkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  80 {
  81         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  82         return -ENOSYS;
  83 }
  84
  85 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  86 {
  87         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  88         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
  89 }
  90
  91 static void digest(struct crypto_tfm *tfm,
  92                    struct scatterlist *sg, unsigned int nsg, u8 *out)
  93 {
  94         init(tfm);
  95         update(tfm, sg, nsg);
  96         final(tfm, out);
  97 }
  98
  99 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
 100 {
 101         return flags ? -EINVAL : 0;
 102 }
 103
 104 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 105 {
 106         struct digest_tfm *ops = &tfm->crt_digest;
 107         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 108
 109         ops->dit_init   = init;
 110         ops->dit_update = update;
 111         ops->dit_final  = final;
 112         ops->dit_digest = digest;
 113         ops->dit_setkey = dalg->dia_setkey ? setkey : nosetkey;
 114
 115         return crypto_alloc_hmac_block(tfm);
 116 }
 117
 118 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 119 {
 120         crypto_free_hmac_block(tfm);
 121 }