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 <crypto/scatterwalk.h>
  16 #include <linux/mm.h>
  17 #include <linux/errno.h>
  18 #include <linux/hardirq.h>
  19 #include <linux/highmem.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/scatterlist.h>
  23
  24 #include "internal.h"
  25
  26 static int init(struct hash_desc *desc)
  27 {
  28         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  29
  30         tfm->__crt_alg->cra_digest.dia_init(tfm);
  31         return 0;
  32 }
  33
  34 static int update2(struct hash_desc *desc,
  35                    struct scatterlist *sg, unsigned int nbytes)
  36 {
  37         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  38         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  39
  40         if (!nbytes)
  41                 return 0;
  42
  43         for (;;) {
  44                 struct page *pg = sg_page(sg);
  45                 unsigned int offset = sg->offset;
  46                 unsigned int l = sg->length;
  47
  48                 if (unlikely(l > nbytes))
  49                         l = nbytes;
  50                 nbytes -= l;
  51
  52                 do {
  53                         unsigned int bytes_from_page = min(l, ((unsigned int)
  54                                                            (PAGE_SIZE)) -
  55                                                            offset);
  56                         char *src = crypto_kmap(pg, 0);
  57                         char *p = src + offset;
  58
  59                         if (unlikely(offset & alignmask)) {
  60                                 unsigned int bytes =
  61                                         alignmask + 1 - (offset & alignmask);
  62                                 bytes = min(bytes, bytes_from_page);
  63                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  64                                                                       bytes);
  65                                 p += bytes;
  66                                 bytes_from_page -= bytes;
  67                                 l -= bytes;
  68                         }
  69                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  70                                                               bytes_from_page);
  71                         crypto_kunmap(src, 0);
  72                         crypto_yield(desc->flags);
  73                         offset = 0;
  74                         pg++;
  75                         l -= bytes_from_page;
  76                 } while (l > 0);
  77
  78                 if (!nbytes)
  79                         break;
  80                 sg = scatterwalk_sg_next(sg);
  81         }
  82
  83         return 0;
  84 }
  85
  86 static int update(struct hash_desc *desc,
  87                   struct scatterlist *sg, unsigned int nbytes)
  88 {
  89         if (WARN_ON_ONCE(in_irq()))
  90                 return -EDEADLK;
  91         return update2(desc, sg, nbytes);
  92 }
  93
  94 static int final(struct hash_desc *desc, u8 *out)
  95 {
  96         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  97         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  98         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
  99
 100         if (unlikely((unsigned long)out & alignmask)) {
 101                 unsigned long align = alignmask + 1;
 102                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
 103                 u8 *dst = (u8 *)ALIGN(addr, align) +
 104                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 105
 106                 digest->dia_final(tfm, dst);
 107                 memcpy(out, dst, digest->dia_digestsize);
 108         } else
 109                 digest->dia_final(tfm, out);
 110
 111         return 0;
 112 }
 113
 114 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 115 {
 116         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 117         return -ENOSYS;
 118 }
 119
 120 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 121 {
 122         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 123
 124         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 125         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 126 }
 127
 128 static int digest(struct hash_desc *desc,
 129                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 130 {
 131         if (WARN_ON_ONCE(in_irq()))
 132                 return -EDEADLK;
 133
 134         init(desc);
 135         update2(desc, sg, nbytes);
 136         return final(desc, out);
 137 }
 138
 139 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 140 {
 141         struct hash_tfm *ops = &tfm->crt_hash;
 142         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 143
 144         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
 145                 return -EINVAL;
 146
 147         ops->init       = init;
 148         ops->update     = update;
 149         ops->final      = final;
 150         ops->digest     = digest;
 151         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 152         ops->digestsize = dalg->dia_digestsize;
 153
 154         return 0;
 155 }
 156
 157 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 158 {
 159 }