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
  15 #include <linux/mm.h>
  16 #include <linux/errno.h>
  17 #include <linux/highmem.h>
  18 #include <linux/module.h>
  19 #include <linux/scatterlist.h>
  20
  21 #include "internal.h"
  22 #include "scatterwalk.h"
  23
  24 static int init(struct hash_desc *desc)
  25 {
  26         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  27
  28         tfm->__crt_alg->cra_digest.dia_init(tfm);
  29         return 0;
  30 }
  31
  32 static int update(struct hash_desc *desc,
  33                   struct scatterlist *sg, unsigned int nbytes)
  34 {
  35         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  36         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  37
  38         if (!nbytes)
  39                 return 0;
  40
  41         for (;;) {
  42                 struct page *pg = sg->page;
  43                 unsigned int offset = sg->offset;
  44                 unsigned int l = sg->length;
  45
  46                 if (unlikely(l > nbytes))
  47                         l = nbytes;
  48                 nbytes -= l;
  49
  50                 do {
  51                         unsigned int bytes_from_page = min(l, ((unsigned int)
  52                                                            (PAGE_SIZE)) -
  53                                                            offset);
  54                         char *src = crypto_kmap(pg, 0);
  55                         char *p = src + offset;
  56
  57                         if (unlikely(offset & alignmask)) {
  58                                 unsigned int bytes =
  59                                         alignmask + 1 - (offset & alignmask);
  60                                 bytes = min(bytes, bytes_from_page);
  61                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  62                                                                       bytes);
  63                                 p += bytes;
  64                                 bytes_from_page -= bytes;
  65                                 l -= bytes;
  66                         }
  67                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  68                                                               bytes_from_page);
  69                         crypto_kunmap(src, 0);
  70                         crypto_yield(desc->flags);
  71                         offset = 0;
  72                         pg++;
  73                         l -= bytes_from_page;
  74                 } while (l > 0);
  75
  76                 if (!nbytes)
  77                         break;
  78                 sg = sg_next(sg);
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int final(struct hash_desc *desc, u8 *out)
  85 {
  86         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  87         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  88         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
  89
  90         if (unlikely((unsigned long)out & alignmask)) {
  91                 unsigned long align = alignmask + 1;
  92                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
  93                 u8 *dst = (u8 *)ALIGN(addr, align) +
  94                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
  95
  96                 digest->dia_final(tfm, dst);
  97                 memcpy(out, dst, digest->dia_digestsize);
  98         } else
  99                 digest->dia_final(tfm, out);
 100
 101         return 0;
 102 }
 103
 104 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 105 {
 106         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 107         return -ENOSYS;
 108 }
 109
 110 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 111 {
 112         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 113
 114         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 115         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 116 }
 117
 118 static int digest(struct hash_desc *desc,
 119                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 120 {
 121         init(desc);
 122         update(desc, sg, nbytes);
 123         return final(desc, out);
 124 }
 125
 126 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
 127 {
 128         return flags ? -EINVAL : 0;
 129 }
 130
 131 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 132 {
 133         struct hash_tfm *ops = &tfm->crt_hash;
 134         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 135
 136         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
 137                 return -EINVAL;
 138
 139         ops->init       = init;
 140         ops->update     = update;
 141         ops->final      = final;
 142         ops->digest     = digest;
 143         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 144         ops->digestsize = dalg->dia_digestsize;
 145
 146         return 0;
 147 }
 148
 149 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 150 {
 151 }