fs_publish_ublock.c

Go to the documentation of this file.

/*
     This file is part of GNUnet.
     Copyright (C) 2009, 2010, 2012, 2013 GNUnet e.V.
 
     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.
 
     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Affero General Public License for more details.
 
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_constants.h"
#include "gnunet_signatures.h"
#include "fs_publish_ublock.h"
#include "fs_api.h"
#include "fs_tree.h"
 
 
static void
derive_ublock_encryption_key (struct GNUNET_CRYPTO_AeadSecretKey *skey,
                              struct GNUNET_CRYPTO_AeadNonce
                              *iv,
                              const char *label,
                              const struct GNUNET_CRYPTO_EddsaPublicKey *pub)
{
  struct GNUNET_HashCode key;
 
  /* derive key from 'label' and public key of the namespace */
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CRYPTO_hkdf_gnunet (
                   &key, sizeof(key),
                   "UBLOCK-ENC", strlen ("UBLOCK-ENC"),
                   label, strlen (label),
                   GNUNET_CRYPTO_kdf_arg_auto (pub)));
  GNUNET_FS_hash_to_symmetric_key (&key, skey, iv);
}
 
 
void
GNUNET_FS_ublock_decrypt_ (const void *input,
                           size_t input_len,
                           const struct GNUNET_CRYPTO_EddsaPublicKey *ns,
                           const char *label,
                           void *output)
{
  struct GNUNET_CRYPTO_AeadNonce iv;
  struct GNUNET_CRYPTO_AeadSecretKey skey;
  struct GNUNET_CRYPTO_AeadMac *mac;
 
  derive_ublock_encryption_key (&skey, &iv,
                                label, ns);
  mac = (struct GNUNET_CRYPTO_AeadMac*) (((char*) input) + input_len - sizeof *
                                         mac);
  GNUNET_CRYPTO_aead_decrypt (input_len - sizeof (*mac),
                              input,
                              0,
                              NULL,
                              &skey,
                              &iv,
                              mac,
                              output);
}
 
 
struct GNUNET_FS_PublishUblockContext
{
  GNUNET_FS_UBlockContinuation cont;
 
  void *cont_cls;
 
  struct GNUNET_DATASTORE_QueueEntry *qre;
 
  struct GNUNET_SCHEDULER_Task *task;
};
 
 
static void
ublock_put_cont (void *cls,
                 int32_t success,
                 struct GNUNET_TIME_Absolute min_expiration,
                 const char *msg)
{
  struct GNUNET_FS_PublishUblockContext *uc = cls;
 
  uc->qre = NULL;
  uc->cont (uc->cont_cls, msg);
  GNUNET_free (uc);
}
 
 
static void
run_cont (void *cls)
{
  struct GNUNET_FS_PublishUblockContext *uc = cls;
 
  uc->task = NULL;
  uc->cont (uc->cont_cls, NULL);
  GNUNET_free (uc);
}
 
 
struct GNUNET_FS_PublishUblockContext *
GNUNET_FS_publish_ublock_ (struct GNUNET_FS_Handle *h,
                           struct GNUNET_DATASTORE_Handle *dsh,
                           const char *label,
                           const char *ulabel,
                           const struct GNUNET_CRYPTO_EddsaPrivateKey *ns,
                           const struct GNUNET_FS_MetaData *meta,
                           const struct GNUNET_FS_Uri *uri,
                           const struct GNUNET_FS_BlockOptions *bo,
                           enum GNUNET_FS_PublishOptions options,
                           GNUNET_FS_UBlockContinuation cont, void *cont_cls)
{
  struct GNUNET_FS_PublishUblockContext *uc;
  struct GNUNET_HashCode query;
  struct GNUNET_CRYPTO_AeadNonce iv;
  struct GNUNET_CRYPTO_AeadSecretKey skey;
  struct GNUNET_CRYPTO_EddsaPrivateScalar nsd;
  struct GNUNET_CRYPTO_EddsaPublicKey pub;
  char *uris;
  size_t size;
  char *kbe;
  char *sptr;
  ssize_t mdsize;
  size_t slen;
  size_t ulen;
  struct UBlock *ub_plain;
  struct UBlock *ub_enc;
 
  /* compute ublock to publish */
  if (NULL == meta)
    mdsize = 0;
  else
    mdsize = GNUNET_FS_meta_data_get_serialized_size (meta);
  GNUNET_assert (mdsize >= 0);
  uris = GNUNET_FS_uri_to_string (uri);
  slen = strlen (uris) + 1;
  if (NULL == ulabel)
    ulen = 1;
  else
    ulen = strlen (ulabel) + 1;
  size = mdsize + sizeof(struct UBlock) + slen + ulen;
  if (size > MAX_UBLOCK_SIZE)
  {
    size = MAX_UBLOCK_SIZE;
    mdsize = size - sizeof(struct UBlock) - (slen + ulen);
  }
  ub_plain = GNUNET_malloc (size);
  kbe = (char *) &ub_plain[1];
  if (NULL != ulabel)
    GNUNET_memcpy (kbe, ulabel, ulen);
  kbe += ulen;
  GNUNET_memcpy (kbe, uris, slen);
  kbe += slen;
  GNUNET_free (uris);
  sptr = kbe;
  if (NULL != meta)
    mdsize =
      GNUNET_FS_meta_data_serialize (meta, &sptr, mdsize,
                                     GNUNET_FS_META_DATA_SERIALIZE_PART);
  if (-1 == mdsize)
  {
    GNUNET_break (0);
    GNUNET_free (ub_plain);
    cont (cont_cls, _ ("Internal error."));
    return NULL;
  }
  size = sizeof(struct UBlock) + slen + mdsize + ulen + sizeof (struct
                                                                GNUNET_CRYPTO_AeadMac);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Publishing under identifier `%s'\n",
              label);
  /* get public key of the namespace */
  GNUNET_CRYPTO_eddsa_key_get_public (ns,
                                      &pub);
  derive_ublock_encryption_key (&skey, &iv,
                                label, &pub);
 
  /* encrypt ublock */
  {
    struct GNUNET_CRYPTO_AeadMac *mac;
    ub_enc = GNUNET_malloc (size);
    mac = (struct GNUNET_CRYPTO_AeadMac*) (((char*) &ub_enc[1]) + size - sizeof
                                           *mac);
    GNUNET_CRYPTO_aead_encrypt (ulen + slen + mdsize,
                                (unsigned char*) &ub_plain[1],
                                0,
                                NULL,
                                &skey,
                                &iv,
                                &ub_enc[1],
                                mac);
  }
  GNUNET_free (ub_plain);
  ub_enc->purpose.size = htonl (size
                                - sizeof(struct GNUNET_CRYPTO_EddsaSignature));
  ub_enc->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_FS_UBLOCK);
 
  /* derive signing-key from 'label' and public key of the namespace */
  GNUNET_CRYPTO_eddsa_private_key_derive (ns, label, "fs-ublock", &nsd);
  GNUNET_CRYPTO_eddsa_key_get_public_from_scalar (&nsd,
                                                  &ub_enc->verification_key);
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_CRYPTO_eddsa_sign_derived (ns,
                                                   label,
                                                   "fs-ublock",
                                                   &ub_enc->purpose,
                                                   &ub_enc->signature));
  GNUNET_CRYPTO_hash (&ub_enc->verification_key,
                      sizeof(ub_enc->verification_key),
                      &query);
 
  uc = GNUNET_new (struct GNUNET_FS_PublishUblockContext);
  uc->cont = cont;
  uc->cont_cls = cont_cls;
  if (NULL != dsh)
  {
    uc->qre =
      GNUNET_DATASTORE_put (dsh,
                            0,
                            &query,
                            size,
                            ub_enc,
                            GNUNET_BLOCK_TYPE_FS_UBLOCK,
                            bo->content_priority,
                            bo->anonymity_level,
                            bo->replication_level,
                            bo->expiration_time,
                            -2, 1,
                            &ublock_put_cont, uc);
  }
  else
  {
    uc->task = GNUNET_SCHEDULER_add_now (&run_cont,
                                         uc);
  }
  GNUNET_free (ub_enc);
  return uc;
}
 
 
void
GNUNET_FS_publish_ublock_cancel_ (struct GNUNET_FS_PublishUblockContext *uc)
{
  if (NULL != uc->qre)
    GNUNET_DATASTORE_cancel (uc->qre);
  if (NULL != uc->task)
    GNUNET_SCHEDULER_cancel (uc->task);
  GNUNET_free (uc);
}
 
 
/* end of fs_publish_ublock.c */