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 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 update2(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(sg);
  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 = scatterwalk_sg_next(sg);
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int update(struct hash_desc *desc,
  85                   struct scatterlist *sg, unsigned int nbytes)
  86 {
  87         if (WARN_ON_ONCE(in_irq()))
  88                 return -EDEADLK;
  89         return update2(desc, sg, nbytes);
  90 }
  91
  92 static int final(struct hash_desc *desc, u8 *out)
  93 {
  94         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  95         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  96         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
  97
  98         if (unlikely((unsigned long)out & alignmask)) {
  99                 unsigned long align = alignmask + 1;
 100                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
 101                 u8 *dst = (u8 *)ALIGN(addr, align) +
 102                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 103
 104                 digest->dia_final(tfm, dst);
 105                 memcpy(out, dst, digest->dia_digestsize);
 106         } else
 107                 digest->dia_final(tfm, out);
 108
 109         return 0;
 110 }
 111
 112 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 113 {
 114         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 115         return -ENOSYS;
 116 }
 117
 118 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 119 {
 120         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 121
 122         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 123         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 124 }
 125
 126 static int digest(struct hash_desc *desc,
 127                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 128 {
 129         if (WARN_ON_ONCE(in_irq()))
 130                 return -EDEADLK;
 131
 132         init(desc);
 133         update2(desc, sg, nbytes);
 134         return final(desc, out);
 135 }
 136
 137 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 138 {
 139         struct hash_tfm *ops = &tfm->crt_hash;
 140         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 141
 142         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
 143                 return -EINVAL;
 144
 145         ops->init       = init;
 146         ops->update     = update;
 147         ops->final      = final;
 148         ops->digest     = digest;
 149         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 150         ops->digestsize = dalg->dia_digestsize;
 151
 152         return 0;
 153 }
 154
 155 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 156 {
 157 }