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 void crypto_digest_init(struct crypto_tfm *tfm)
  25 {
  26         struct crypto_hash *hash = crypto_hash_cast(tfm);
  27         struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  28
  29         crypto_hash_init(&desc);
  30 }
  31 EXPORT_SYMBOL_GPL(crypto_digest_init);
  32
  33 void crypto_digest_update(struct crypto_tfm *tfm,
  34                           struct scatterlist *sg, unsigned int nsg)
  35 {
  36         struct crypto_hash *hash = crypto_hash_cast(tfm);
  37         struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  38         unsigned int nbytes = 0;
  39         unsigned int i;
  40
  41         for (i = 0; i < nsg; i++)
  42                 nbytes += sg[i].length;
  43
  44         crypto_hash_update(&desc, sg, nbytes);
  45 }
  46 EXPORT_SYMBOL_GPL(crypto_digest_update);
  47
  48 void crypto_digest_final(struct crypto_tfm *tfm, u8 *out)
  49 {
  50         struct crypto_hash *hash = crypto_hash_cast(tfm);
  51         struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  52
  53         crypto_hash_final(&desc, out);
  54 }
  55 EXPORT_SYMBOL_GPL(crypto_digest_final);
  56
  57 void crypto_digest_digest(struct crypto_tfm *tfm,
  58                           struct scatterlist *sg, unsigned int nsg, u8 *out)
  59 {
  60         struct crypto_hash *hash = crypto_hash_cast(tfm);
  61         struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  62         unsigned int nbytes = 0;
  63         unsigned int i;
  64
  65         for (i = 0; i < nsg; i++)
  66                 nbytes += sg[i].length;
  67
  68         crypto_hash_digest(&desc, sg, nbytes, out);
  69 }
  70 EXPORT_SYMBOL_GPL(crypto_digest_digest);
  71
  72 static int init(struct hash_desc *desc)
  73 {
  74         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  75
  76         tfm->__crt_alg->cra_digest.dia_init(tfm);
  77         return 0;
  78 }
  79
  80 static int update(struct hash_desc *desc,
  81                   struct scatterlist *sg, unsigned int nbytes)
  82 {
  83         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  84         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  85
  86         if (!nbytes)
  87                 return 0;
  88
  89         for (;;) {
  90                 struct page *pg = sg->page;
  91                 unsigned int offset = sg->offset;
  92                 unsigned int l = sg->length;
  93
  94                 if (unlikely(l > nbytes))
  95                         l = nbytes;
  96                 nbytes -= l;
  97
  98                 do {
  99                         unsigned int bytes_from_page = min(l, ((unsigned int)
 100                                                            (PAGE_SIZE)) -
 101                                                            offset);
 102                         char *src = crypto_kmap(pg, 0);
 103                         char *p = src + offset;
 104
 105                         if (unlikely(offset & alignmask)) {
 106                                 unsigned int bytes =
 107                                         alignmask + 1 - (offset & alignmask);
 108                                 bytes = min(bytes, bytes_from_page);
 109                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
 110                                                                       bytes);
 111                                 p += bytes;
 112                                 bytes_from_page -= bytes;
 113                                 l -= bytes;
 114                         }
 115                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
 116                                                               bytes_from_page);
 117                         crypto_kunmap(src, 0);
 118                         crypto_yield(desc->flags);
 119                         offset = 0;
 120                         pg++;
 121                         l -= bytes_from_page;
 122                 } while (l > 0);
 123
 124                 if (!nbytes)
 125                         break;
 126                 sg = sg_next(sg);
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int final(struct hash_desc *desc, u8 *out)
 133 {
 134         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
 135         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 136         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
 137
 138         if (unlikely((unsigned long)out & alignmask)) {
 139                 unsigned long align = alignmask + 1;
 140                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
 141                 u8 *dst = (u8 *)ALIGN(addr, align) +
 142                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 143
 144                 digest->dia_final(tfm, dst);
 145                 memcpy(out, dst, digest->dia_digestsize);
 146         } else
 147                 digest->dia_final(tfm, out);
 148
 149         return 0;
 150 }
 151
 152 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 153 {
 154         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 155         return -ENOSYS;
 156 }
 157
 158 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 159 {
 160         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 161
 162         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 163         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 164 }
 165
 166 static int digest(struct hash_desc *desc,
 167                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 168 {
 169         init(desc);
 170         update(desc, sg, nbytes);
 171         return final(desc, out);
 172 }
 173
 174 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
 175 {
 176         return flags ? -EINVAL : 0;
 177 }
 178
 179 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 180 {
 181         struct hash_tfm *ops = &tfm->crt_hash;
 182         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 183
 184         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
 185                 return -EINVAL;
 186
 187         ops->init       = init;
 188         ops->update     = update;
 189         ops->final      = final;
 190         ops->digest     = digest;
 191         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 192         ops->digestsize = dalg->dia_digestsize;
 193
 194         return 0;
 195 }
 196
 197 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 198 {
 199 }