serval-dna/rhizome.c

/*
Serval DNA Rhizome file distribution
Copyright (C) 2012-2013 Serval Project Inc.
Copyright (C) 2011-2012 Paul Gardner-Stephen
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program 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 General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

/*
  Portions Copyright (C) 2013 Petter Reinholdtsen
  Some rights reserved

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdlib.h>
#include <assert.h>
#include "serval.h"
#include "conf.h"
#include "str.h"
#include "rhizome.h"
#include "dataformats.h"

int is_rhizome_enabled()
{
  return config.rhizome.enable;
}

int is_rhizome_http_enabled()
{
  return config.rhizome.enable
    &&   config.rhizome.http.enable
    &&   rhizome_db;
}

int is_rhizome_mdp_enabled()
{
  return config.rhizome.enable
    &&   config.rhizome.mdp.enable
    &&   rhizome_db;
}

int is_rhizome_mdp_server_running()
{
  return is_rhizome_mdp_enabled();
}

int is_rhizome_advertise_enabled()
{
  return config.rhizome.enable
    &&   config.rhizome.advertise.enable
    &&   rhizome_db
    &&   (is_rhizome_http_server_running() || is_rhizome_mdp_server_running());
}

int rhizome_fetch_delay_ms()
{
  return config.rhizome.fetch_delay_ms;
}

/* Import a bundle from a pair of files, one containing the manifest and the optional other
   containing the payload.  The logic is all in rhizome_bundle_import().  This function just wraps
   that function and manages file and object buffers and lifetimes.
*/

int rhizome_bundle_import_files(rhizome_manifest *m, const char *manifest_path, const char *filepath)
{
  if (config.debug.rhizome)
    DEBUGF("(manifest_path=%s, filepath=%s)",
	manifest_path ? alloca_str_toprint(manifest_path) : "NULL",
	filepath ? alloca_str_toprint(filepath) : "NULL");
  
  unsigned char buffer[MAX_MANIFEST_BYTES];
  size_t buffer_len = 0;
  
  // manifest has been appended to the end of the file.
  if (strcmp(manifest_path, filepath)==0){
    unsigned char marker[4];
    int ret=0;
    FILE *f = fopen(filepath, "r");
    
    if (f == NULL)
      return WHYF_perror("Could not open manifest file %s for reading.", filepath);
    
    if (fseek(f, -sizeof(marker), SEEK_END))
      ret=WHY_perror("Unable to seek to end of file");
    
    if (ret==0){
      ret = fread(marker, 1, sizeof(marker), f);
      if (ret==sizeof(marker))
	ret=0;
      else
	ret=WHY_perror("Unable to read end of manifest marker");
    }
    
    if (ret==0){
      if (marker[2]!=0x41 || marker[3]!=0x10)
	ret=WHYF("Expected 0x4110 marker at end of file");
    }
    
    if (ret==0){
      buffer_len = read_uint16(marker);
      if (buffer_len < 1 || buffer_len > MAX_MANIFEST_BYTES)
	ret=WHYF("Invalid manifest length %zu", buffer_len);
    }
    
    if (ret==0){
      if (fseek(f, -(buffer_len+sizeof(marker)), SEEK_END))
	ret=WHY_perror("Unable to seek to end of file");
    }
    
    if (ret==0){
      ret = fread(buffer, 1, buffer_len, f);
      if (ret==buffer_len)
	ret=0;
      else
	ret=WHY_perror("Unable to read manifest contents");
    }
    
    fclose(f);
    
    if (ret)
      return ret;
    
    manifest_path=(char*)buffer;
  }
  
  if (rhizome_read_manifest_file(m, manifest_path, buffer_len) == -1)
    return WHY("could not read manifest file");
  if (!rhizome_manifest_validate(m))
    return WHY("manifest is invalid");
  if (!rhizome_manifest_verify(m))
    return WHY("could not verify manifest");
  
  /* Do we already have this manifest or newer? */
  int64_t dbVersion = -1;
  if (sqlite_exec_int64(&dbVersion, "SELECT version FROM MANIFESTS WHERE id = ?;", RHIZOME_BID_T, &m->cryptoSignPublic, END) == -1)
    return WHY("Select failure");

  if (dbVersion>=m->version)
    return 2;

  int status = rhizome_import_file(m, filepath);
  if (status<0)
    return status;
  
  return rhizome_add_manifest(m, 1);
}

int rhizome_manifest_check_sanity(rhizome_manifest *m)
{
  /* Ensure manifest meets basic sanity checks. */
  int ret = 0;
  if (m->version == 0)
    ret = WHY("Manifest must have a version number");
  if (m->filesize == RHIZOME_SIZE_UNSET)
    ret = WHY("Manifest missing 'filesize' field");
  else if (m->filesize && rhizome_filehash_t_is_zero(m->filehash))
    ret = WHY("Manifest 'filehash' field has not been set");
  if (m->service == NULL)
    ret = WHY("Manifest missing 'service' field");
  else if (strcasecmp(m->service, RHIZOME_SERVICE_FILE) == 0) {
    if (m->name == NULL)
      ret = WHY("Manifest with service='" RHIZOME_SERVICE_FILE "' missing 'name' field");
  } else if (strcasecmp(m->service, RHIZOME_SERVICE_MESHMS) == 0 
	  || strcasecmp(m->service, RHIZOME_SERVICE_MESHMS2) == 0) {
    if (!m->has_sender)
      ret = WHYF("Manifest with service='%s' missing 'sender' field", m->service);
    if (!m->has_recipient)
      ret = WHYF("Manifest with service='%s' missing 'recipient' field", m->service);
  }
  else if (!rhizome_str_is_manifest_service(m->service))
    ret = WHYF("Manifest invalid 'service' field %s", alloca_str_toprint(m->service));
  if (!m->has_date)
    ret = WHY("Manifest missing 'date' field");
  return ret;
}

/* Sets the bundle key "BK" field of a manifest.  Returns 1 if the field was set, 0 if not.
 *
 * This function must not be called unless the bundle secret is known.
 *
 * @author Andrew Bettison <andrew@servalproject.com>
 */
int rhizome_manifest_add_bundle_key(rhizome_manifest *m)
{
  IN();
  assert(m->haveSecret);
  switch (m->authorship) {
    case ANONYMOUS: // there can be no BK field without an author
    case AUTHOR_UNKNOWN: // we already know the author is not in the keyring
    case AUTHENTICATION_ERROR: // already tried and failed to get Rhizome Secret
      break;
    case AUTHOR_NOT_CHECKED:
    case AUTHOR_LOCAL:
    case AUTHOR_AUTHENTIC:
    case AUTHOR_IMPOSTOR: {
	/* Set the BK using the provided author.  Serval Security Framework defines BK as being:
	*    BK = privateKey XOR sha512(RS##BID)
	* where BID = cryptoSignPublic, 
	*       RS is the rhizome secret for the specified author. 
	* The nice thing about this specification is that:
	*    privateKey = BK XOR sha512(RS##BID)
	* so the same function can be used to encrypt and decrypt the BK field.
	*/
	const unsigned char *rs;
	size_t rs_len = 0;
	enum rhizome_secret_disposition d = find_rhizome_secret(&m->author, &rs_len, &rs);
	switch (d) {
	  case FOUND_RHIZOME_SECRET: {
	      rhizome_bk_t bkey;
	      if (rhizome_secret2bk(&m->cryptoSignPublic, rs, rs_len, bkey.binary, m->cryptoSignSecret) == 0) {
		rhizome_manifest_set_bundle_key(m, &bkey);
		m->authorship = AUTHOR_AUTHENTIC;
		RETURN(1);
	      } else
		m->authorship = AUTHENTICATION_ERROR;
	    }
	    break;
	  case IDENTITY_NOT_FOUND:
	    m->authorship = AUTHOR_UNKNOWN;
	    break;
	  case IDENTITY_HAS_NO_RHIZOME_SECRET:
	    m->authorship = AUTHENTICATION_ERROR;
	    break;
	  default:
	    FATALF("find_rhizome_secret() returned unknown code %d", (int)d);
	    break;
	}
      }
      break;
    default:
      FATALF("m->authorship = %d", (int)m->authorship);
  }
  rhizome_manifest_del_bundle_key(m);
  switch (m->authorship) {
    case AUTHOR_UNKNOWN:
      WHYF("Cannot set BK because author=%s is not in keyring", alloca_tohex_sid_t(m->author));
      break;
    case AUTHENTICATION_ERROR:
      WHY("Cannot set BK due to error");
      break;
    default:
      break;
  }
  RETURN(0);
}

int rhizome_add_manifest(rhizome_manifest *m, int ttl)
{
  if (config.debug.rhizome)
    DEBUGF("rhizome_add_manifest(m=%p, ttl=%d)",m, ttl);

  if (m->finalised==0)
    return WHY("Manifest must be finalised before being stored");

  /* Store time to live, clamped to within legal range */
  m->ttl = ttl < 0 ? 0 : ttl > 254 ? 254 : ttl;

  if (rhizome_manifest_check_sanity(m))
    return -1;

  assert(m->filesize != RHIZOME_SIZE_UNSET);
  if (m->filesize > 0 && !rhizome_exists(&m->filehash))
    return WHY("File has not been imported");

  /* If the manifest already has an ID */
  if (rhizome_bid_t_is_zero(m->cryptoSignPublic))
    return WHY("Manifest does not have an ID");   
  
  /* Discard the new manifest unless it is newer than the most recent known version with the same ID */
  int64_t storedversion = -1;
  switch (sqlite_exec_int64(&storedversion, "SELECT version FROM MANIFESTS WHERE id = ?;", RHIZOME_BID_T, &m->cryptoSignPublic, END)) {
    case -1:
      return WHY("Select failed");
    case 0:
      if (config.debug.rhizome) DEBUG("No existing manifest");
      break;
    case 1:
      if (config.debug.rhizome) 
	DEBUGF("Found existing version=%"PRId64", new version=%"PRId64, storedversion, m->version);
      if (m->version < storedversion)
	return WHY("Newer version exists");
      if (m->version == storedversion)
	return WHYF("Already have %s:%"PRId64", not adding", alloca_tohex_rhizome_bid_t(m->cryptoSignPublic), m->version);
      break;
    default:
      return WHY("Select found too many rows!");
  }

  /* Okay, it is written, and can be put directly into the rhizome database now */
  return rhizome_store_bundle(m);
}

/* When voice traffic is being carried, we need to throttle Rhizome down
   to a more sensible level.  Or possibly even supress it entirely.
 */
time_ms_t rhizome_voice_timeout = -1;
int rhizome_saw_voice_traffic()
{
  /* We are in "voice mode" for a second after sending a voice frame */
  rhizome_voice_timeout=gettime_ms()+1000;
  return 0;
}