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/* -*- coding: utf-8 -*- */
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* Mandos client - get and decrypt data from a Mandos server
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* This file demonstrates how to use Avahi's core API, this is
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* the embeddable mDNS stack for embedded applications.
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* This program is partly derived from an example program for an Avahi
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* service browser, downloaded from
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* <http://avahi.org/browser/examples/core-browse-services.c>. This
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* includes the following functions: "resolve_callback",
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* "browse_callback", and parts of "main".
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* Everything else is Copyright © 2007-2008 Teddy Hogeborn and Björn
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
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* <https://www.fukt.bsnet.se/~teddy/>.
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* End user applications should *not* use this API and should use
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* the D-Bus or C APIs, please see
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* client-browse-services.c and glib-integration.c
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* I repeat, you probably do *not* want to use this example.
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#define _FORTIFY_SOURCE 2
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This file is part of avahi.
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avahi is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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avahi is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with avahi; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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#define _LARGEFILE_SOURCE
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#define _FILE_OFFSET_BITS 64
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#include <avahi-common/error.h>
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//mandos client part
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#include <sys/types.h> /* socket(), inet_pton() */
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#include <sys/socket.h> /* socket(), struct sockaddr_in6,
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struct in6_addr, inet_pton() */
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#include <gnutls/gnutls.h> /* All GnuTLS stuff */
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#include <gnutls/openpgp.h> /* GnuTLS with openpgp stuff */
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#include <sys/types.h> /* socket(), setsockopt(), inet_pton() */
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#include <sys/socket.h> /* socket(), setsockopt(), struct sockaddr_in6, struct in6_addr, inet_pton() */
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#include <gnutls/gnutls.h> /* ALL GNUTLS STUFF */
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#include <gnutls/openpgp.h> /* gnutls with openpgp stuff */
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#include <unistd.h> /* close() */
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#include <netinet/in.h>
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} encrypted_session;
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ssize_t pgp_packet_decrypt (char *packet, size_t packet_size,
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char **new_packet, const char *homedir){
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ssize_t gpg_packet_decrypt (char *packet, size_t packet_size, char **new_packet, char *homedir){
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gpgme_data_t dh_crypto, dh_plain;
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ssize_t new_packet_capacity = 0;
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ssize_t new_packet_length = 0;
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size_t new_packet_capacity = 0;
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size_t new_packet_length = 0;
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gpgme_engine_info_t engine_info;
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fprintf(stderr, "Trying to decrypt OpenPGP packet\n");
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gpgme_check_version(NULL);
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rc = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
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if (rc != GPG_ERR_NO_ERROR){
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fprintf(stderr, "bad gpgme_engine_check_version: %s: %s\n",
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gpgme_strsource(rc), gpgme_strerror(rc));
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gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
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/* Set GPGME home directory */
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rc = gpgme_get_engine_info (&engine_info);
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/* Decrypt data from the FILE pointer to the plaintext data
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/* Decrypt data from the FILE pointer to the plaintext data buffer */
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rc = gpgme_op_decrypt(ctx, dh_crypto, dh_plain);
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if (rc != GPG_ERR_NO_ERROR){
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fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
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gpgme_strsource(rc), gpgme_strerror(rc));
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fprintf(stderr, "Decryption of OpenPGP packet succeeded\n");
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gpgme_decrypt_result_t result;
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result = gpgme_op_decrypt_result(ctx);
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fprintf(stderr, "gpgme_op_decrypt_result failed\n");
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fprintf(stderr, "Unsupported algorithm: %s\n",
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result->unsupported_algorithm);
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fprintf(stderr, "Wrong key usage: %d\n",
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result->wrong_key_usage);
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if(result->file_name != NULL){
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fprintf(stderr, "File name: %s\n", result->file_name);
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gpgme_recipient_t recipient;
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recipient = result->recipients;
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while(recipient != NULL){
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fprintf(stderr, "Public key algorithm: %s\n",
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gpgme_pubkey_algo_name(recipient->pubkey_algo));
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fprintf(stderr, "Key ID: %s\n", recipient->keyid);
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fprintf(stderr, "Secret key available: %s\n",
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recipient->status == GPG_ERR_NO_SECKEY
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recipient = recipient->next;
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/* gpgme_decrypt_result_t result; */
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/* result = gpgme_op_decrypt_result(ctx); */
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/* fprintf(stderr, "Unsupported algorithm: %s\n", result->unsupported_algorithm); */
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/* fprintf(stderr, "Wrong key usage: %d\n", result->wrong_key_usage); */
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/* if(result->file_name != NULL){ */
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/* fprintf(stderr, "File name: %s\n", result->file_name); */
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/* gpgme_recipient_t recipient; */
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/* recipient = result->recipients; */
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/* while(recipient != NULL){ */
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/* fprintf(stderr, "Public key algorithm: %s\n", */
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/* gpgme_pubkey_algo_name(recipient->pubkey_algo)); */
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/* fprintf(stderr, "Key ID: %s\n", recipient->keyid); */
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/* fprintf(stderr, "Secret key available: %s\n", */
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/* recipient->status == GPG_ERR_NO_SECKEY ? "No" : "Yes"); */
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/* recipient = recipient->next; */
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/* Delete the GPGME FILE pointer cryptotext data buffer */
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gpgme_data_release(dh_crypto);
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/* Seek back to the beginning of the GPGME plaintext data buffer */
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gpgme_data_seek(dh_plain, (off_t) 0, SEEK_SET);
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gpgme_data_seek(dh_plain, 0, SEEK_SET);
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if (new_packet_length + BUFFER_SIZE > new_packet_capacity){
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*new_packet = realloc(*new_packet,
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(unsigned int)new_packet_capacity
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*new_packet = realloc(*new_packet, new_packet_capacity + BUFFER_SIZE);
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if (*new_packet == NULL){
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perror("realloc");
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fprintf(stderr, "Initializing GnuTLS\n");
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if ((ret = gnutls_global_init ())
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!= GNUTLS_E_SUCCESS) {
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fprintf (stderr, "global_init: %s\n", safer_gnutls_strerror(ret));
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gnutls_global_set_log_level(11);
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gnutls_global_set_log_function(debuggnutls);
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/* Uncomment to enable full debuggin on the gnutls library */
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/* gnutls_global_set_log_level(11); */
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/* gnutls_global_set_log_function(debuggnutls); */
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/* openpgp credentials */
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if ((ret = gnutls_certificate_allocate_credentials (&es->cred))
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!= GNUTLS_E_SUCCESS) {
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fprintf (stderr, "memory error: %s\n",
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safer_gnutls_strerror(ret));
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fprintf (stderr, "memory error: %s\n", safer_gnutls_strerror(ret));
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fprintf(stderr, "Attempting to use OpenPGP certificate %s"
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" and keyfile %s as GnuTLS credentials\n", certfile,
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ret = gnutls_certificate_set_openpgp_key_file
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(es->cred, certfile, certkey, GNUTLS_OPENPGP_FMT_BASE64);
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(es->cred, CERTFILE, KEYFILE, GNUTLS_OPENPGP_FMT_BASE64);
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if (ret != GNUTLS_E_SUCCESS) {
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(stderr, "Error[%d] while reading the OpenPGP key pair ('%s',"
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ret, certfile, certkey);
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(stderr, "Error[%d] while reading the OpenPGP key pair ('%s', '%s')\n",
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ret, CERTFILE, KEYFILE);
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fprintf(stdout, "The Error is: %s\n",
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safer_gnutls_strerror(ret));
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//GnuTLS server initialization
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//Gnutls server initialization
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if ((ret = gnutls_dh_params_init (&es->dh_params))
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!= GNUTLS_E_SUCCESS) {
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fprintf (stderr, "Error in dh parameter initialization: %s\n",
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safer_gnutls_strerror(ret));
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if ((ret = gnutls_dh_params_generate2 (es->dh_params, DH_BITS))
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!= GNUTLS_E_SUCCESS) {
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fprintf (stderr, "Error in prime generation: %s\n",
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safer_gnutls_strerror(ret));
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gnutls_certificate_set_dh_params (es->cred, es->dh_params);
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// GnuTLS session creation
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// Gnutls session creation
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if ((ret = gnutls_init (&es->session, GNUTLS_SERVER))
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!= GNUTLS_E_SUCCESS){
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fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
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fprintf(stderr, "Error in gnutls session initialization: %s\n",
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safer_gnutls_strerror(ret));
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if ((ret = gnutls_priority_set_direct (es->session, "NORMAL", &err))
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!= GNUTLS_E_SUCCESS) {
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fprintf(stderr, "Syntax error at: %s\n", err);
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fprintf(stderr, "GnuTLS error: %s\n",
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fprintf(stderr, "Gnutls error: %s\n",
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safer_gnutls_strerror(ret));
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if ((ret = gnutls_credentials_set
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(es->session, GNUTLS_CRD_CERTIFICATE, es->cred))
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!= GNUTLS_E_SUCCESS) {
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safer_gnutls_strerror(ret));
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/* ignore client certificate if any. */
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gnutls_certificate_server_set_request (es->session,
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gnutls_certificate_server_set_request (es->session, GNUTLS_CERT_IGNORE);
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gnutls_dh_set_prime_bits (es->session, DH_BITS);
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void empty_log(__attribute__((unused)) AvahiLogLevel level,
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__attribute__((unused)) const char *txt){}
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void empty_log(AvahiLogLevel level, const char *txt){}
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int start_mandos_communication(const char *ip, uint16_t port,
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unsigned int if_index){
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int start_mandos_communcation(char *ip, uint16_t port){
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struct sockaddr_in6 to;
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struct in6_addr ip_addr;
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encrypted_session es;
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char *buffer = NULL;
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char *decrypted_buffer;
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size_t buffer_length = 0;
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size_t buffer_capacity = 0;
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ssize_t decrypted_buffer_size;
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char interface[IF_NAMESIZE];
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fprintf(stderr, "Setting up a tcp connection to %s\n", ip);
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tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
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if(if_indextoname(if_index, interface) == NULL){
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perror("if_indextoname");
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ret = setsockopt(tcp_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);
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perror("setsockopt bindtodevice");
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fprintf(stderr, "Binding to interface %s\n", interface);
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memset(&to,0,sizeof(to)); /* Spurious warning */
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memset(&to,0,sizeof(to));
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to.sin6_family = AF_INET6;
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ret = inet_pton(AF_INET6, ip, &to.sin6_addr);
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ret = inet_pton(AF_INET6, ip, &ip_addr);
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perror("inet_pton");
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gnutls_transport_set_ptr (es.session,
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(gnutls_transport_ptr_t) tcp_sd);
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fprintf(stderr, "Establishing TLS session with %s\n", ip);
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gnutls_transport_set_ptr (es.session, (gnutls_transport_ptr_t) tcp_sd);
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ret = gnutls_handshake (es.session);
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if (ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "\n*** Handshake failed ***\n");
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fprintf(stderr, "\n*** Handshake failed ***\n");
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//Retrieve OpenPGP packet that contains the wanted password
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fprintf(stderr, "Retrieving pgp encrypted password from %s\n",
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if (buffer_length + BUFFER_SIZE > buffer_capacity){
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buffer = realloc(buffer, buffer_capacity + BUFFER_SIZE);
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fprintf(stderr, "Unknown error while reading data from"
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" encrypted session with mandos server\n");
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fprintf(stderr, "Unknown error while reading data from encrypted session with mandos server\n");
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gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
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buffer_length += (size_t) ret;
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buffer_length += ret;
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if (buffer_length > 0){
483
decrypted_buffer_size = pgp_packet_decrypt(buffer,
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if (decrypted_buffer_size >= 0){
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while(written < decrypted_buffer_size){
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ret = (int)fwrite (decrypted_buffer + written, 1,
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(size_t)decrypted_buffer_size - written,
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if(ret == 0 and ferror(stdout)){
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fprintf(stderr, "Error writing encrypted data: %s\n",
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written += (size_t)ret;
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if ((decrypted_buffer_size = gpg_packet_decrypt(buffer, buffer_length, &decrypted_buffer, CERT_ROOT)) == 0){
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fwrite (decrypted_buffer, 1, decrypted_buffer_size, stdout);
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free(decrypted_buffer);
508
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//shutdown procedure
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fprintf(stderr, "Closing TLS session\n");
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gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
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const char *host_name,
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const AvahiAddress *address,
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AVAHI_GCC_UNUSED AvahiStringList *txt,
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AVAHI_GCC_UNUSED AvahiLookupResultFlags flags,
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AvahiStringList *txt,
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AvahiLookupResultFlags flags,
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AVAHI_GCC_UNUSED void* userdata) {
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assert(r); /* Spurious warning */
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/* Called whenever a service has been resolved successfully or
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case AVAHI_RESOLVER_FAILURE:
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fprintf(stderr, "(Resolver) Failed to resolve service '%s' of"
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" type '%s' in domain '%s': %s\n", name, type, domain,
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avahi_strerror(avahi_server_errno(server)));
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case AVAHI_RESOLVER_FOUND:
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char ip[AVAHI_ADDRESS_STR_MAX];
558
avahi_address_snprint(ip, sizeof(ip), address);
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fprintf(stderr, "Mandos server \"%s\" found on %s (%s) on"
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" port %d\n", name, host_name, ip, port);
563
int ret = start_mandos_communication(ip, port,
564
(unsigned int) interface);
441
/* Called whenever a service has been resolved successfully or timed out */
444
case AVAHI_RESOLVER_FAILURE:
445
fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_server_errno(server)));
448
case AVAHI_RESOLVER_FOUND: {
449
char ip[AVAHI_ADDRESS_STR_MAX];
450
avahi_address_snprint(ip, sizeof(ip), address);
451
int ret = start_mandos_communcation(ip, port);
570
avahi_s_service_resolver_free(r);
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avahi_s_service_resolver_free(r);
573
462
static void browse_callback(
582
471
void* userdata) {
584
473
AvahiServer *s = userdata;
585
assert(b); /* Spurious warning */
587
/* Called whenever a new services becomes available on the LAN or
588
is removed from the LAN */
476
/* Called whenever a new services becomes available on the LAN or is removed from the LAN */
592
case AVAHI_BROWSER_FAILURE:
594
fprintf(stderr, "(Browser) %s\n",
595
avahi_strerror(avahi_server_errno(server)));
596
avahi_simple_poll_quit(simple_poll);
599
case AVAHI_BROWSER_NEW:
600
/* We ignore the returned resolver object. In the callback
601
function we free it. If the server is terminated before
602
the callback function is called the server will free
603
the resolver for us. */
605
if (!(avahi_s_service_resolver_new(s, interface, protocol, name,
607
AVAHI_PROTO_INET6, 0,
608
resolve_callback, s)))
609
fprintf(stderr, "Failed to resolve service '%s': %s\n", name,
610
avahi_strerror(avahi_server_errno(s)));
613
case AVAHI_BROWSER_REMOVE:
616
case AVAHI_BROWSER_ALL_FOR_NOW:
617
case AVAHI_BROWSER_CACHE_EXHAUSTED:
480
case AVAHI_BROWSER_FAILURE:
482
fprintf(stderr, "(Browser) %s\n", avahi_strerror(avahi_server_errno(server)));
483
avahi_simple_poll_quit(simple_poll);
486
case AVAHI_BROWSER_NEW:
487
/* We ignore the returned resolver object. In the callback
488
function we free it. If the server is terminated before
489
the callback function is called the server will free
490
the resolver for us. */
492
if (!(avahi_s_service_resolver_new(s, interface, protocol, name, type, domain, AVAHI_PROTO_INET6, 0, resolve_callback, s)))
493
fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_server_errno(s)));
497
case AVAHI_BROWSER_REMOVE:
500
case AVAHI_BROWSER_ALL_FOR_NOW:
501
case AVAHI_BROWSER_CACHE_EXHAUSTED:
622
/* combinds two strings and returns the malloced new string. som sane checks could/should be added */
623
const char *combinestrings(const char *first, const char *second){
625
tmp = malloc(strlen(first) + strlen(second));
636
506
int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char*argv[]) {
637
507
AvahiServerConfig config;
638
508
AvahiSServiceBrowser *sb = NULL;
641
int returncode = EXIT_SUCCESS;
642
const char *interface = "eth0";
645
static struct option long_options[] = {
646
{"debug", no_argument, (int *)&debug, 1},
647
{"interface", required_argument, 0, 'i'},
648
{"certdir", required_argument, 0, 'd'},
649
{"certkey", required_argument, 0, 'c'},
650
{"certfile", required_argument, 0, 'k'},
653
int option_index = 0;
654
ret = getopt_long (argc, argv, "i:", long_options,
681
certfile = combinestrings(certdir, certfile);
682
if (certfile == NULL){
686
certkey = combinestrings(certdir, certkey);
687
if (certkey == NULL){
692
avahi_set_log_function(empty_log);
512
avahi_set_log_function(empty_log);
695
514
/* Initialize the psuedo-RNG */
696
srand((unsigned int) time(NULL));
698
517
/* Allocate main loop object */
699
518
if (!(simple_poll = avahi_simple_poll_new())) {
700
519
fprintf(stderr, "Failed to create simple poll object.\n");
705
523
/* Do not publish any local records */
709
527
config.publish_workstation = 0;
710
528
config.publish_domain = 0;
530
/* /\* Set a unicast DNS server for wide area DNS-SD *\/ */
531
/* avahi_address_parse("193.11.177.11", AVAHI_PROTO_UNSPEC, &config.wide_area_servers[0]); */
532
/* config.n_wide_area_servers = 1; */
533
/* config.enable_wide_area = 1; */
712
535
/* Allocate a new server */
713
server = avahi_server_new(avahi_simple_poll_get(simple_poll),
714
&config, NULL, NULL, &error);
536
server = avahi_server_new(avahi_simple_poll_get(simple_poll), &config, NULL, NULL, &error);
716
538
/* Free the configuration data */
717
539
avahi_server_config_free(&config);
719
/* Check if creating the server object succeeded */
541
/* Check wether creating the server object succeeded */
721
fprintf(stderr, "Failed to create server: %s\n",
722
avahi_strerror(error));
723
returncode = EXIT_FAILURE;
543
fprintf(stderr, "Failed to create server: %s\n", avahi_strerror(error));
727
547
/* Create the service browser */
728
sb = avahi_s_service_browser_new(server,
730
if_nametoindex(interface),
732
"_mandos._tcp", NULL, 0,
733
browse_callback, server);
735
fprintf(stderr, "Failed to create service browser: %s\n",
736
avahi_strerror(avahi_server_errno(server)));
737
returncode = EXIT_FAILURE;
548
if (!(sb = avahi_s_service_browser_new(server, if_nametoindex("eth0"), AVAHI_PROTO_INET6, "_mandos._tcp", NULL, 0, browse_callback, server))) {
549
fprintf(stderr, "Failed to create service browser: %s\n", avahi_strerror(avahi_server_errno(server)));
741
553
/* Run the main loop */
744
fprintf(stderr, "Starting avahi loop search\n");
747
554
avahi_simple_poll_loop(simple_poll);
752
fprintf(stderr, "%s exiting\n", argv[0]);
755
560
/* Cleanup things */