32
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/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
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#define _LARGEFILE_SOURCE
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#ifndef _FILE_OFFSET_BITS
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#define _FILE_OFFSET_BITS 64
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
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stdout, ferror(), remove() */
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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 <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
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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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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
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getuid(), getgid(), setuid(),
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getuid(), getgid(), seteuid(),
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#include <arpa/inet.h> /* inet_pton(), htons */
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#include <iso646.h> /* not, or, and */
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#include <argp.h> /* struct argp_option, error_t, struct
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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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sigaction(), SIGTERM, sig_atomic_t,
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_NOHOST, EX_IOERR, EX_PROTOCOL */
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#include <sys/klog.h> /* klogctl() */
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
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sig_atomic_t quit_now = 0;
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int signal_received = 0;
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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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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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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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static int init_gnutls_session(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_init(session, GNUTLS_SERVER);
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} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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if(ret != GNUTLS_E_SUCCESS){
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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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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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gnutls_deinit(*session);
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} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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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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ret = gnutls_credentials_set(*session, GNUTLS_CRD_CERTIFICATE,
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gnutls_deinit(*session);
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} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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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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/* ignore client certificate if any. */
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gnutls_certificate_server_set_request(*session,
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gnutls_certificate_server_set_request(*session, GNUTLS_CERT_IGNORE);
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gnutls_dh_set_prime_bits(*session, mc.dh_bits);
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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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int ret, tcp_sd = -1;
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struct sockaddr_in in;
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struct sockaddr_in6 in6;
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char *buffer = NULL;
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char *decrypted_buffer;
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char *decrypted_buffer = NULL;
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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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gnutls_session_t session;
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int pf; /* Protocol family */
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tcp_sd = socket(pf, SOCK_STREAM, 0);
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perror("socket");
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memset(&to, 0, sizeof(to));
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if(af == AF_INET6){
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to.in6.sin6_family = (uint16_t)af;
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to.in6.sin6_family = (sa_family_t)af;
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ret = inet_pton(af, ip, &to.in6.sin6_addr);
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} else { /* IPv4 */
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to.in.sin_family = (sa_family_t)af;
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ret = inet_pton(af, ip, &to.in.sin_addr);
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perror("inet_pton");
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fprintf(stderr, "Bad address: %s\n", ip);
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if(af == AF_INET6){
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to.in6.sin6_port = htons(port); /* Spurious warnings from
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if(if_index == AVAHI_IF_UNSPEC){
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fprintf(stderr, "An IPv6 link-local address is incomplete"
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" without a network interface\n");
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/* Set the network interface number as scope */
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to.in6.sin6_scope_id = (uint32_t)if_index;
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if(af == AF_INET6){
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ret = connect(tcp_sd, &to.in6, sizeof(to));
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ret = connect(tcp_sd, &to.in, sizeof(to)); /* IPv4 */
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perror("connect");
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const char *out = mandos_protocol_version;
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fprintf(stderr, "Establishing TLS session with %s\n", ip);
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gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) tcp_sd);
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ret = gnutls_handshake(session);
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} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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if(ret != GNUTLS_E_SUCCESS){
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case GNUTLS_E_AGAIN:
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case GNUTLS_E_REHANDSHAKE:
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ret = gnutls_handshake(session);
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} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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fprintf(stderr, "*** GnuTLS Re-handshake failed ***\n");
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gnutls_perror(ret);
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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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gnutls_bye(session, GNUTLS_SHUT_RDWR);
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fprintf(stderr, "Closing TLS session\n");
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gnutls_bye(session, GNUTLS_SHUT_RDWR);
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ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
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} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
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if(buffer_length > 0){
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ssize_t decrypted_buffer_size;
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decrypted_buffer_size = pgp_packet_decrypt(buffer,
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&decrypted_buffer);
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if(decrypted_buffer_size >= 0){
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while(written < (size_t) 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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strerror(errno));
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written += (size_t)ret;
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free(decrypted_buffer);
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/* Shutdown procedure */
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ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
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free(decrypted_buffer);
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ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
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gnutls_deinit(session);
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gnutls_deinit(session);
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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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static void handle_sigterm(int sig){
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signal_received = 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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bool gpgme_initialized = false;
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float delay = 2.5f;
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struct sigaction old_sigterm_action;
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struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
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struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
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/* Lower any group privileges we might have, just to be safe */
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/* Lower user privileges (temporarily) */
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struct argp_option options[] = {
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{ .name = "debug", .key = 128,
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.arg = "SECONDS",
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.doc = "Maximum delay to wait for interface startup",
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* These reproduce what we would get without ARGP_NO_HELP
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{ .name = "help", .key = '?',
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.doc = "Give this help list", .group = -1 },
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{ .name = "usage", .key = -3,
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.doc = "Give a short usage message", .group = -1 },
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{ .name = "version", .key = 'V',
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.doc = "Print program version", .group = -1 },
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{ .name = NULL }
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error_t parse_opt(int key, char *arg,
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struct argp_state *state){
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case 128: /* --debug */
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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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fprintf(stderr, "Bad number of DH bits\n");
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argp_error(state, "Bad number of DH bits");
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mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
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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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fprintf(stderr, "Bad delay\n");
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argp_error(state, "Bad delay");
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* These reproduce what we would get without ARGP_NO_HELP
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case '?': /* --help */
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argp_state_help(state, state->out_stream,
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(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1161
& ~(unsigned int)ARGP_HELP_EXIT_OK);
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case -3: /* --usage */
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argp_state_help(state, state->out_stream,
1164
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
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case 'V': /* --version */
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fprintf(state->out_stream, "%s\n", argp_program_version);
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exit(argp_err_exit_status);
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return ARGP_ERR_UNKNOWN;
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struct argp argp = { .options = options, .parser = parse_opt,
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1176
.args_doc = "",
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.doc = "Mandos client -- Get and decrypt"
1006
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" passwords from a Mandos server" };
1007
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
1008
if(ret == ARGP_ERR_UNKNOWN){
1009
fprintf(stderr, "Unknown error while parsing arguments\n");
1010
exitcode = EXIT_FAILURE;
1179
ret = argp_parse(&argp, argc, argv,
1180
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1187
perror("argp_parse");
1188
exitcode = EX_OSERR;
1191
exitcode = EX_USAGE;
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mc.simple_poll = avahi_simple_poll_new();
1024
1205
if(mc.simple_poll == NULL){
1025
1206
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1026
exitcode = EXIT_FAILURE;
1207
exitcode = EX_UNAVAILABLE;
1031
1212
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1033
1214
perror("sigaddset");
1034
exitcode = EXIT_FAILURE;
1215
exitcode = EX_OSERR;
1037
1218
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1039
1220
perror("sigaddset");
1040
exitcode = EXIT_FAILURE;
1221
exitcode = EX_OSERR;
1043
1224
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1045
1226
perror("sigaddset");
1046
exitcode = EXIT_FAILURE;
1049
ret = sigaction(SIGTERM, &sigterm_action, &old_sigterm_action);
1051
perror("sigaction");
1052
exitcode = EXIT_FAILURE;
1227
exitcode = EX_OSERR;
1230
/* Need to check if the handler is SIG_IGN before handling:
1231
| [[info:libc:Initial Signal Actions]] |
1232
| [[info:libc:Basic Signal Handling]] |
1234
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1236
perror("sigaction");
1239
if(old_sigterm_action.sa_handler != SIG_IGN){
1240
ret = sigaction(SIGINT, &sigterm_action, NULL);
1242
perror("sigaction");
1243
exitcode = EX_OSERR;
1247
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1249
perror("sigaction");
1252
if(old_sigterm_action.sa_handler != SIG_IGN){
1253
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1255
perror("sigaction");
1256
exitcode = EX_OSERR;
1260
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1262
perror("sigaction");
1265
if(old_sigterm_action.sa_handler != SIG_IGN){
1266
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1268
perror("sigaction");
1269
exitcode = EX_OSERR;
1056
1274
/* If the interface is down, bring it up */
1057
1275
if(interface[0] != '\0'){
1276
if_index = (AvahiIfIndex) if_nametoindex(interface);
1278
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1279
exitcode = EX_UNAVAILABLE;
1287
/* Re-raise priviliges */
1058
1294
#ifdef __linux__
1059
1295
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1060
messages to mess up the prompt */
1296
messages about the network interface to mess up the prompt */
1061
1297
ret = klogctl(8, NULL, 5);
1062
1298
bool restore_loglevel = true;
1094
1336
#endif /* __linux__ */
1095
exitcode = EXIT_FAILURE;
1337
exitcode = EX_OSERR;
1338
/* Lower privileges */
1098
1346
if((network.ifr_flags & IFF_UP) == 0){
1099
1347
network.ifr_flags |= IFF_UP;
1348
take_down_interface = true;
1100
1349
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1351
take_down_interface = false;
1102
1352
perror("ioctl SIOCSIFFLAGS");
1103
exitcode = EXIT_FAILURE;
1353
exitcode = EX_OSERR;
1104
1354
#ifdef __linux__
1105
1355
if(restore_loglevel){
1106
1356
ret = klogctl(7, NULL, 0);
1141
1400
#endif /* __linux__ */
1401
/* Lower privileges */
1403
if(take_down_interface){
1404
/* Lower privileges */
1410
/* Lower privileges permanently */
1158
1422
ret = init_gnutls_global(pubkey, seckey);
1160
1424
fprintf(stderr, "init_gnutls_global failed\n");
1161
exitcode = EXIT_FAILURE;
1425
exitcode = EX_UNAVAILABLE;
1164
1428
gnutls_initialized = true;
1435
tempdir_created = true;
1167
1436
if(mkdtemp(tempdir) == NULL){
1437
tempdir_created = false;
1168
1438
perror("mkdtemp");
1171
tempdir_created = true;
1173
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1174
1447
fprintf(stderr, "init_gpgme failed\n");
1175
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1178
1451
gpgme_initialized = true;
1181
if(interface[0] != '\0'){
1182
if_index = (AvahiIfIndex) if_nametoindex(interface);
1184
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1185
exitcode = EXIT_FAILURE;
1190
1458
if(connect_to != NULL){
1193
1461
char *address = strrchr(connect_to, ':');
1194
1462
if(address == NULL){
1195
1463
fprintf(stderr, "No colon in address\n");
1196
exitcode = EXIT_FAILURE;
1464
exitcode = EX_USAGE;
1201
1474
tmpmax = strtoimax(address+1, &tmp, 10);
1202
1475
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1203
1476
or tmpmax != (uint16_t)tmpmax){
1204
1477
fprintf(stderr, "Bad port number\n");
1205
exitcode = EXIT_FAILURE;
1478
exitcode = EX_USAGE;
1208
1486
port = (uint16_t)tmpmax;
1209
1487
*address = '\0';
1210
1488
address = connect_to;
1218
1501
ret = start_mandos_communication(address, port, if_index, af);
1220
exitcode = EXIT_FAILURE;
1507
exitcode = EX_NOHOST;
1510
exitcode = EX_USAGE;
1513
exitcode = EX_IOERR;
1516
exitcode = EX_PROTOCOL;
1519
exitcode = EX_OSERR;
1222
1523
exitcode = EXIT_SUCCESS;
1228
1533
AvahiServerConfig config;
1229
1534
/* Do not publish any local Zeroconf records */
1295
1608
gpgme_release(mc.ctx);
1611
/* Take down the network interface */
1612
if(take_down_interface){
1613
/* Re-raise priviliges */
1620
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1622
perror("ioctl SIOCGIFFLAGS");
1623
} else if(network.ifr_flags & IFF_UP) {
1624
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1625
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1627
perror("ioctl SIOCSIFFLAGS");
1630
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1634
/* Lower privileges permanently */
1298
1643
/* Removes the temp directory used by GPGME */
1299
1644
if(tempdir_created){
1688
sigemptyset(&old_sigterm_action.sa_mask);
1689
old_sigterm_action.sa_handler = SIG_DFL;
1690
ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
1691
&old_sigterm_action,
1694
perror("sigaction");
1697
ret = raise(signal_received);
1698
} while(ret != 0 and errno == EINTR);
1703
TEMP_FAILURE_RETRY(pause());
1342
1706
return exitcode;