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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
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#include <stdio.h> /* fprintf(), stderr, fwrite(),
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stdout, ferror(), remove() */
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stdout, ferror(), sscanf(),
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#include <stdint.h> /* uint16_t, uint32_t */
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
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#include <stdbool.h> /* bool, false, true */
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#include <string.h> /* memset(), strcmp(), strlen(),
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strerror(), asprintf(), strcpy() */
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#include <fcntl.h> /* open() */
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#include <dirent.h> /* opendir(), struct dirent, readdir()
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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
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#include <time.h> /* nanosleep(), time() */
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argp_state, struct argp,
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argp_parse(), ARGP_KEY_ARG,
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ARGP_KEY_END, ARGP_ERR_UNKNOWN */
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#include <signal.h> /* sigemptyset(), sigaddset(),
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sigaction(), SIGTERM, sigaction,
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#include <sys/klog.h> /* klogctl() */
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#endif /* __linux__ */
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/* All Avahi types, constants and functions
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} mandos_context;
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/* global context so signal handler can reach it*/
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mandos_context mc = { .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
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* Make additional room in "buffer" for at least BUFFER_SIZE more
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* bytes. "buffer_capacity" is how much is currently allocated,
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* "buffer_length" is how much is already used.
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* Make additional room in "buffer" for at least BUFFER_SIZE
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* additional bytes. "buffer_capacity" is how much is currently
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* allocated, "buffer_length" is how much is already used.
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size_t incbuffer(char **buffer, size_t buffer_length,
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size_t buffer_capacity){
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* Initialize GPGME.
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static bool init_gpgme(const char *seckey,
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static bool init_gpgme(mandos_context *mc, const char *seckey,
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const char *pubkey, const char *tempdir){
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gpgme_error_t rc;
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rc = gpgme_op_import(mc.ctx, pgp_data);
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rc = gpgme_op_import(mc->ctx, pgp_data);
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if(rc != GPG_ERR_NO_ERROR){
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fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
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gpgme_strsource(rc), gpgme_strerror(rc));
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/* Create new GPGME "context" */
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rc = gpgme_new(&(mc.ctx));
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rc = gpgme_new(&(mc->ctx));
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if(rc != GPG_ERR_NO_ERROR){
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fprintf(stderr, "bad gpgme_new: %s: %s\n",
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gpgme_strsource(rc), gpgme_strerror(rc));
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* Decrypt OpenPGP data.
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* Returns -1 on error
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static ssize_t pgp_packet_decrypt(const char *cryptotext,
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static ssize_t pgp_packet_decrypt(const mandos_context *mc,
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const char *cryptotext,
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size_t crypto_size,
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char **plaintext){
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gpgme_data_t dh_crypto, dh_plain;
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/* Decrypt data from the cryptotext data buffer to the plaintext
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rc = gpgme_op_decrypt(mc.ctx, dh_crypto, dh_plain);
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rc = gpgme_op_decrypt(mc->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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plaintext_length = -1;
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gpgme_decrypt_result_t result;
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result = gpgme_op_decrypt_result(mc.ctx);
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result = gpgme_op_decrypt_result(mc->ctx);
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if(result == NULL){
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fprintf(stderr, "gpgme_op_decrypt_result failed\n");
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fprintf(stderr, "GnuTLS: %s", string);
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static int init_gnutls_global(const char *pubkeyfilename,
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static int init_gnutls_global(mandos_context *mc,
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const char *pubkeyfilename,
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const char *seckeyfilename){
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/* OpenPGP credentials */
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gnutls_certificate_allocate_credentials(&mc.cred);
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gnutls_certificate_allocate_credentials(&mc->cred);
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
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ret = gnutls_certificate_set_openpgp_key_file
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(mc.cred, pubkeyfilename, seckeyfilename,
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(mc->cred, pubkeyfilename, seckeyfilename,
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GNUTLS_OPENPGP_FMT_BASE64);
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if(ret != GNUTLS_E_SUCCESS){
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/* GnuTLS server initialization */
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ret = gnutls_dh_params_init(&mc.dh_params);
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ret = gnutls_dh_params_init(&mc->dh_params);
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
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" %s\n", safer_gnutls_strerror(ret));
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ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
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ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
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safer_gnutls_strerror(ret));
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gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
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gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
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gnutls_certificate_free_credentials(mc.cred);
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gnutls_certificate_free_credentials(mc->cred);
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gnutls_global_deinit();
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gnutls_dh_params_deinit(mc.dh_params);
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gnutls_dh_params_deinit(mc->dh_params);
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static int init_gnutls_session(gnutls_session_t *session){
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static int init_gnutls_session(mandos_context *mc,
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gnutls_session_t *session){
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/* GnuTLS session creation */
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ret = gnutls_init(session, GNUTLS_SERVER);
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ret = gnutls_priority_set_direct(*session, mc.priority, &err);
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ret = gnutls_priority_set_direct(*session, mc->priority, &err);
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if(ret != 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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ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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if(ret != GNUTLS_E_SUCCESS){
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fprintf(stderr, "Error setting GnuTLS credentials: %s\n",
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safer_gnutls_strerror(ret));
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gnutls_certificate_server_set_request(*session,
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GNUTLS_CERT_IGNORE);
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gnutls_dh_set_prime_bits(*session, mc.dh_bits);
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gnutls_dh_set_prime_bits(*session, mc->dh_bits);
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/* Called when a Mandos server is found */
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static int start_mandos_communication(const char *ip, uint16_t port,
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AvahiIfIndex if_index,
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mandos_context *mc, int af){
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gnutls_bye(session, GNUTLS_SHUT_RDWR);
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if(buffer_length > 0){
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decrypted_buffer_size = pgp_packet_decrypt(buffer,
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decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
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&decrypted_buffer);
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if(decrypted_buffer_size >= 0){
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AVAHI_GCC_UNUSED AvahiStringList *txt,
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AVAHI_GCC_UNUSED AvahiLookupResultFlags
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AVAHI_GCC_UNUSED void* userdata){
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mandos_context *mc = userdata;
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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, "(Avahi Resolver) Failed to resolve service '%s'"
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" of type '%s' in domain '%s': %s\n", name, type, domain,
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avahi_strerror(avahi_server_errno(mc.server)));
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avahi_strerror(avahi_server_errno(mc->server)));
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case AVAHI_RESOLVER_FOUND:
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PRIdMAX ") on port %" PRIu16 "\n", name, host_name,
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ip, (intmax_t)interface, port);
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int ret = start_mandos_communication(ip, port, interface,
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int ret = start_mandos_communication(ip, port, interface, mc,
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avahi_proto_to_af(proto));
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avahi_simple_poll_quit(mc.simple_poll);
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avahi_simple_poll_quit(mc->simple_poll);
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case AVAHI_BROWSER_FAILURE:
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fprintf(stderr, "(Avahi browser) %s\n",
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avahi_strerror(avahi_server_errno(mc.server)));
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avahi_simple_poll_quit(mc.simple_poll);
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avahi_strerror(avahi_server_errno(mc->server)));
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avahi_simple_poll_quit(mc->simple_poll);
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case AVAHI_BROWSER_NEW:
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the callback function is called the Avahi server will free the
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resolver for us. */
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if(!(avahi_s_service_resolver_new(mc.server, interface,
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if(!(avahi_s_service_resolver_new(mc->server, interface,
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protocol, name, type, domain,
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AVAHI_PROTO_INET6, 0,
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resolve_callback, NULL)))
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resolve_callback, mc)))
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fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
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name, avahi_strerror(avahi_server_errno(mc.server)));
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name, avahi_strerror(avahi_server_errno(mc->server)));
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case AVAHI_BROWSER_REMOVE:
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sig_atomic_t quit_now = 0;
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/* stop main loop after sigterm has been called */
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static void handle_sigterm(__attribute__((unused)) int sig){
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int old_errno = errno;
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if(mc.simple_poll != NULL){
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avahi_simple_poll_quit(mc.simple_poll);
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int main(int argc, char *argv[]){
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AvahiSServiceBrowser *sb = NULL;
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int exitcode = EXIT_SUCCESS;
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const char *interface = "eth0";
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struct ifreq network;
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const char *seckey = PATHDIR "/" SECKEY;
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const char *pubkey = PATHDIR "/" PUBKEY;
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/* Initialize Mandos context */
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mc = (mandos_context){ .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
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mandos_context mc = { .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
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bool gnutls_initialized = false;
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bool gpgme_initialized = false;
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struct sigaction old_sigterm_action;
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struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
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struct argp_option options[] = {
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case 129: /* --dh-bits */
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tmpmax = strtoimax(arg, &tmp, 10);
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if(errno != 0 or tmp == arg or *tmp != '\0'
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or tmpmax != (typeof(mc.dh_bits))tmpmax){
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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad number of DH bits\n");
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exit(EXIT_FAILURE);
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mc.priority = arg;
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case 131: /* --delay */
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delay = strtof(arg, &tmp);
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if(errno != 0 or tmp == arg or *tmp != '\0'){
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ret = sscanf(arg, "%lf%n", &delay, &numchars);
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if(ret < 1 or arg[numchars] != '\0'){
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fprintf(stderr, "Bad delay\n");
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exit(EXIT_FAILURE);
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avahi_set_log_function(empty_log);
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/* Initialize Avahi early so avahi_simple_poll_quit() can be called
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from the signal handler */
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/* Initialize the pseudo-RNG for Avahi */
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srand((unsigned int) time(NULL));
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mc.simple_poll = avahi_simple_poll_new();
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if(mc.simple_poll == NULL){
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fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
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exitcode = EXIT_FAILURE;
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sigemptyset(&sigterm_action.sa_mask);
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ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
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perror("sigaddset");
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exitcode = EXIT_FAILURE;
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ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
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perror("sigaddset");
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exitcode = EXIT_FAILURE;
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ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
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perror("sigaddset");
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exitcode = EXIT_FAILURE;
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ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
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perror("sigaction");
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exitcode = EXIT_FAILURE;
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/* If the interface is down, bring it up */
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if(interface[0] != '\0'){
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#ifdef __linux__
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1094
perror("setuid");
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ret = init_gnutls_global(pubkey, seckey);
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ret = init_gnutls_global(&mc, pubkey, seckey);
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fprintf(stderr, "init_gnutls_global failed\n");
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exitcode = EXIT_FAILURE;
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tempdir_created = true;
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if(not init_gpgme(pubkey, seckey, tempdir)){
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if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
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fprintf(stderr, "init_gpgme failed\n");
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exitcode = EXIT_FAILURE;
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tmpmax = strtoimax(address+1, &tmp, 10);
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if(errno != 0 or tmp == address+1 or *tmp != '\0'
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or tmpmax != (uint16_t)tmpmax){
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ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (uint16_t)tmpmax
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or address[numchars+1] != '\0'){
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fprintf(stderr, "Bad port number\n");
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exitcode = EXIT_FAILURE;
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ret = start_mandos_communication(address, port, if_index, af);
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ret = start_mandos_communication(address, port, if_index, &mc,
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exitcode = EXIT_FAILURE;
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avahi_set_log_function(empty_log);
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/* Initialize the pseudo-RNG for Avahi */
1171
srand((unsigned int) time(NULL));
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/* Allocate main Avahi loop object */
1174
mc.simple_poll = avahi_simple_poll_new();
1175
if(mc.simple_poll == NULL){
1176
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1177
exitcode = EXIT_FAILURE;
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1182
AvahiServerConfig config;
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1183
/* Do not publish any local Zeroconf records */
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1207
/* Create the Avahi service browser */
1259
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
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1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1261
NULL, 0, browse_callback, NULL);
1210
NULL, 0, browse_callback, &mc);
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1211
if(sb == NULL){
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fprintf(stderr, "Failed to create service browser: %s\n",
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1213
avahi_strerror(avahi_server_errno(mc.server)));