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/internal/hash.h>
  16 #include <crypto/scatterwalk.h>
  17 #include <linux/mm.h>
  18 #include <linux/errno.h>
  19 #include <linux/hardirq.h>
  20 #include <linux/highmem.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/scatterlist.h>
  24
  25 #include "internal.h"
  26
  27 static int init(struct hash_desc *desc)
  28 {
  29         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  30
  31         tfm->__crt_alg->cra_digest.dia_init(tfm);
  32         return 0;
  33 }
  34
  35 static int update2(struct hash_desc *desc,
  36                    struct scatterlist *sg, unsigned int nbytes)
  37 {
  38         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  39         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  40
  41         if (!nbytes)
  42                 return 0;
  43
  44         for (;;) {
  45                 struct page *pg = sg_page(sg);
  46                 unsigned int offset = sg->offset;
  47                 unsigned int l = sg->length;
  48
  49                 if (unlikely(l > nbytes))
  50                         l = nbytes;
  51                 nbytes -= l;
  52
  53                 do {
  54                         unsigned int bytes_from_page = min(l, ((unsigned int)
  55                                                            (PAGE_SIZE)) -
  56                                                            offset);
  57                         char *src = crypto_kmap(pg, 0);
  58                         char *p = src + offset;
  59
  60                         if (unlikely(offset & alignmask)) {
  61                                 unsigned int bytes =
  62                                         alignmask + 1 - (offset & alignmask);
  63                                 bytes = min(bytes, bytes_from_page);
  64                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  65                                                                       bytes);
  66                                 p += bytes;
  67                                 bytes_from_page -= bytes;
  68                                 l -= bytes;
  69                         }
  70                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  71                                                               bytes_from_page);
  72                         crypto_kunmap(src, 0);
  73                         crypto_yield(desc->flags);
  74                         offset = 0;
  75                         pg++;
  76                         l -= bytes_from_page;
  77                 } while (l > 0);
  78
  79                 if (!nbytes)
  80                         break;
  81                 sg = scatterwalk_sg_next(sg);
  82         }
  83
  84         return 0;
  85 }
  86
  87 static int update(struct hash_desc *desc,
  88                   struct scatterlist *sg, unsigned int nbytes)
  89 {
  90         if (WARN_ON_ONCE(in_irq()))
  91                 return -EDEADLK;
  92         return update2(desc, sg, nbytes);
  93 }
  94
  95 static int final(struct hash_desc *desc, u8 *out)
  96 {
  97         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  98         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  99         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
 100
 101         if (unlikely((unsigned long)out & alignmask)) {
 102                 unsigned long align = alignmask + 1;
 103                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
 104                 u8 *dst = (u8 *)ALIGN(addr, align) +
 105                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 106
 107                 digest->dia_final(tfm, dst);
 108                 memcpy(out, dst, digest->dia_digestsize);
 109         } else
 110                 digest->dia_final(tfm, out);
 111
 112         return 0;
 113 }
 114
 115 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 116 {
 117         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 118         return -ENOSYS;
 119 }
 120
 121 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 122 {
 123         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 124
 125         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 126         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 127 }
 128
 129 static int digest(struct hash_desc *desc,
 130                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 131 {
 132         if (WARN_ON_ONCE(in_irq()))
 133                 return -EDEADLK;
 134
 135         init(desc);
 136         update2(desc, sg, nbytes);
 137         return final(desc, out);
 138 }
 139
 140 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 141 {
 142         struct hash_tfm *ops = &tfm->crt_hash;
 143         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 144
 145         if (dalg->dia_digestsize > PAGE_SIZE / 8)
 146                 return -EINVAL;
 147
 148         ops->init       = init;
 149         ops->update     = update;
 150         ops->final      = final;
 151         ops->digest     = digest;
 152         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 153         ops->digestsize = dalg->dia_digestsize;
 154
 155         return 0;
 156 }
 157
 158 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 159 {
 160 }
 161
 162 static int digest_async_nosetkey(struct crypto_ahash *tfm_async, const u8 *key,
 163                         unsigned int keylen)
 164 {
 165         crypto_ahash_clear_flags(tfm_async, CRYPTO_TFM_RES_MASK);
 166         return -ENOSYS;
 167 }
 168
 169 static int digest_async_setkey(struct crypto_ahash *tfm_async, const u8 *key,
 170                         unsigned int keylen)
 171 {
 172         struct crypto_tfm    *tfm        = crypto_ahash_tfm(tfm_async);
 173         struct digest_alg    *dalg       = &tfm->__crt_alg->cra_digest;
 174
 175         crypto_ahash_clear_flags(tfm_async, CRYPTO_TFM_RES_MASK);
 176         return dalg->dia_setkey(tfm, key, keylen);
 177 }
 178
 179 static int digest_async_init(struct ahash_request *req)
 180 {
 181         struct crypto_tfm *tfm  = req->base.tfm;
 182         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 183
 184         dalg->dia_init(tfm);
 185         return 0;
 186 }
 187
 188 static int digest_async_update(struct ahash_request *req)
 189 {
 190         struct crypto_tfm *tfm = req->base.tfm;
 191         struct hash_desc  desc = {
 192                 .tfm   = __crypto_hash_cast(tfm),
 193                 .flags = req->base.flags,
 194         };
 195
 196         update(&desc, req->src, req->nbytes);
 197         return 0;
 198 }
 199
 200 static int digest_async_final(struct ahash_request *req)
 201 {
 202         struct crypto_tfm *tfm  = req->base.tfm;
 203         struct hash_desc  desc = {
 204                 .tfm   = __crypto_hash_cast(tfm),
 205                 .flags = req->base.flags,
 206         };
 207
 208         final(&desc, req->result);
 209         return 0;
 210 }
 211
 212 static int digest_async_digest(struct ahash_request *req)
 213 {
 214         struct crypto_tfm *tfm  = req->base.tfm;
 215         struct hash_desc  desc = {
 216                 .tfm   = __crypto_hash_cast(tfm),
 217                 .flags = req->base.flags,
 218         };
 219
 220         return digest(&desc, req->src, req->nbytes, req->result);
 221 }
 222
 223 int crypto_init_digest_ops_async(struct crypto_tfm *tfm)
 224 {
 225         struct ahash_tfm  *crt  = &tfm->crt_ahash;
 226         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 227
 228         if (dalg->dia_digestsize > PAGE_SIZE / 8)
 229                 return -EINVAL;
 230
 231         crt->init       = digest_async_init;
 232         crt->update     = digest_async_update;
 233         crt->final      = digest_async_final;
 234         crt->digest     = digest_async_digest;
 235         crt->setkey     = dalg->dia_setkey ? digest_async_setkey :
 236                                                 digest_async_nosetkey;
 237         crt->digestsize = dalg->dia_digestsize;
 238
 239         return 0;
 240 }