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