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/* Needed by GPGME, specifically gpgme_data_seek() */
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#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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#include <stdio.h> /* fprintf(), stderr, fwrite(),
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stdout, ferror(), sscanf(),
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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 <stdbool.h> /* bool, true */
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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 <sys/ioctl.h> /* ioctl */
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#include <sys/ioctl.h> /* ioctl */
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#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
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sockaddr_in6, PF_INET6,
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SOCK_STREAM, INET6_ADDRSTRLEN,
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uid_t, gid_t, open(), opendir(),
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SOCK_STREAM, uid_t, gid_t, open(),
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#include <sys/stat.h> /* open() */
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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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inet_pton(), connect() */
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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, intmax_t, SCNdMAX */
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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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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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#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
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SIOCSIFFLAGS, if_indextoname(),
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if_nametoindex(), IF_NAMESIZE */
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#include <netinet/in.h>
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#include <netinet/in.h> /* IN6_IS_ADDR_LINKLOCAL,
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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, and, or */
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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_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, sig_atomic_t,
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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 room in "buffer" for at least BUFFER_SIZE additional bytes.
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* "buffer_capacity" is how much is currently allocated,
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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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size_t adjustbuffer(char **buffer, size_t buffer_length,
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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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if(buffer_length + BUFFER_SIZE > buffer_capacity){
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*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
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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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/* 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(mandos_context *mc,
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gnutls_session_t *session){
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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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static void empty_log(__attribute__((unused)) AvahiLogLevel level,
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__attribute__((unused)) const char *txt){}
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sig_atomic_t quit_now = 0;
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int signal_received = 0;
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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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int ret, tcp_sd = -1;
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union { struct sockaddr in; struct sockaddr_in6 in6; } to;
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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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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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gnutls_session_t session;
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ret = init_gnutls_session(mc, &session);
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int pf; /* Protocol family */
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fprintf(stderr, "Bad address family: %d\n", af);
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ret = init_gnutls_session(&session);
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fprintf(stderr, "Setting up a tcp connection to %s, port %" PRIu16
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fprintf(stderr, "Setting up a TCP connection to %s, port %" PRIu16
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tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
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tcp_sd = socket(pf, SOCK_STREAM, 0);
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perror("socket");
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if(if_indextoname((unsigned int)if_index, interface) == NULL){
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perror("if_indextoname");
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fprintf(stderr, "Binding to interface %s\n", interface);
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memset(&to, 0, sizeof(to));
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to.in6.sin6_family = AF_INET6;
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/* It would be nice to have a way to detect if we were passed an
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IPv4 address here. Now we assume an IPv6 address. */
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ret = inet_pton(AF_INET6, ip, &to.in6.sin6_addr);
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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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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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to.in6.sin6_port = htons(port); /* Spurious warnings from
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to.in6.sin6_port = htons(port); /* Spurious warnings from
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-Wunreachable-code */
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if(IN6_IS_ADDR_LINKLOCAL /* Spurious warnings from */
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(&to.in6.sin6_addr)){ /* -Wstrict-aliasing=2 or lower and
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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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to.in.sin_port = htons(port); /* Spurious warnings from
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-Wunreachable-code */
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to.in6.sin6_scope_id = (uint32_t)if_index;
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fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
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char addrstr[INET6_ADDRSTRLEN] = "";
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if(inet_ntop(to.in6.sin6_family, &(to.in6.sin6_addr), addrstr,
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sizeof(addrstr)) == NULL){
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if(af == AF_INET6 and if_index != AVAHI_IF_UNSPEC){
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char interface[IF_NAMESIZE];
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if(if_indextoname((unsigned int)if_index, interface) == NULL){
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perror("if_indextoname");
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fprintf(stderr, "Connection to: %s%%%s, port %" PRIu16 "\n",
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ip, interface, port);
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fprintf(stderr, "Connection to: %s, port %" PRIu16 "\n", ip,
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char addrstr[(INET_ADDRSTRLEN > INET6_ADDRSTRLEN) ?
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INET_ADDRSTRLEN : INET6_ADDRSTRLEN] = "";
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pcret = inet_ntop(af, &(to.in6.sin6_addr), addrstr,
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pcret = inet_ntop(af, &(to.in.sin_addr), addrstr,
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perror("inet_ntop");
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if(strcmp(addrstr, ip) != 0){
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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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protocol, name, type, domain,
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AVAHI_PROTO_INET6, 0,
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resolve_callback, mc)))
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if(avahi_s_service_resolver_new(mc.server, interface, protocol,
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name, type, domain, protocol, 0,
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resolve_callback, NULL) == NULL)
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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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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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/* Need to check if the handler is SIG_IGN before handling:
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| [[info:libc:Initial Signal Actions]] |
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| [[info:libc:Basic Signal Handling]] |
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ret = sigaction(SIGINT, NULL, &old_sigterm_action);
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perror("sigaction");
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return EXIT_FAILURE;
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if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &sigterm_action, NULL);
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perror("sigaction");
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exitcode = EXIT_FAILURE;
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ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
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perror("sigaction");
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return EXIT_FAILURE;
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if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &sigterm_action, NULL);
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perror("sigaction");
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exitcode = EXIT_FAILURE;
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ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
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perror("sigaction");
1192
return EXIT_FAILURE;
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if(old_sigterm_action.sa_handler != SIG_IGN){
1195
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1197
perror("sigaction");
1198
exitcode = EXIT_FAILURE;
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/* If the interface is down, bring it up */
1204
if(interface[0] != '\0'){
1205
if_index = (AvahiIfIndex) if_nametoindex(interface);
1207
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1208
exitcode = EXIT_FAILURE;
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/* Re-raise priviliges */
948
1223
#ifdef __linux__
949
1224
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
950
1225
messages to mess up the prompt */
951
1226
ret = klogctl(8, NULL, 5);
1227
bool restore_loglevel = true;
1229
restore_loglevel = false;
953
1230
perror("klogctl");
1232
#endif /* __linux__ */
957
1234
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
959
1236
perror("socket");
960
1237
exitcode = EXIT_FAILURE;
961
1238
#ifdef __linux__
962
ret = klogctl(7, NULL, 0);
1239
if(restore_loglevel){
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ret = klogctl(7, NULL, 0);
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#endif /* __linux__ */
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/* Lower privileges */
969
1254
strcpy(network.ifr_name, interface);
972
1257
perror("ioctl SIOCGIFFLAGS");
973
1258
#ifdef __linux__
974
ret = klogctl(7, NULL, 0);
1259
if(restore_loglevel){
1260
ret = klogctl(7, NULL, 0);
1265
#endif /* __linux__ */
1266
exitcode = EXIT_FAILURE;
1267
/* Lower privileges */
979
exitcode = EXIT_FAILURE;
982
1275
if((network.ifr_flags & IFF_UP) == 0){
983
1276
network.ifr_flags |= IFF_UP;
1277
take_down_interface = true;
984
1278
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1280
take_down_interface = false;
986
1281
perror("ioctl SIOCSIFFLAGS");
987
1282
exitcode = EXIT_FAILURE;
988
1283
#ifdef __linux__
989
ret = klogctl(7, NULL, 0);
1284
if(restore_loglevel){
1285
ret = klogctl(7, NULL, 0);
1290
#endif /* __linux__ */
1291
/* Lower privileges */
1008
1311
perror("nanosleep");
1011
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1314
if(not take_down_interface){
1315
/* We won't need the socket anymore */
1316
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1015
1321
#ifdef __linux__
1016
/* Restores kernel loglevel to default */
1017
ret = klogctl(7, NULL, 0);
1037
ret = init_gnutls_global(&mc, pubkey, seckey);
1322
if(restore_loglevel){
1323
/* Restores kernel loglevel to default */
1324
ret = klogctl(7, NULL, 0);
1329
#endif /* __linux__ */
1330
/* Lower privileges */
1332
if(take_down_interface){
1333
/* Lower privileges */
1339
/* Lower privileges permanently */
1351
ret = init_gnutls_global(pubkey, seckey);
1039
1353
fprintf(stderr, "init_gnutls_global failed\n");
1040
1354
exitcode = EXIT_FAILURE;
1073
1393
exitcode = EXIT_FAILURE;
1077
ret = sscanf(address+1, "%" SCNdMAX "%n", &tmpmax, &numchars);
1078
if(ret < 1 or tmpmax != (uint16_t)tmpmax
1079
or address[numchars+1] != '\0'){
1403
tmpmax = strtoimax(address+1, &tmp, 10);
1404
if(errno != 0 or tmp == address+1 or *tmp != '\0'
1405
or tmpmax != (uint16_t)tmpmax){
1080
1406
fprintf(stderr, "Bad port number\n");
1081
1407
exitcode = EXIT_FAILURE;
1084
1415
port = (uint16_t)tmpmax;
1085
1416
*address = '\0';
1086
1417
address = connect_to;
1087
ret = start_mandos_communication(address, port, if_index, &mc);
1418
/* Colon in address indicates IPv6 */
1420
if(strchr(address, ':') != NULL){
1430
ret = start_mandos_communication(address, port, if_index, af);
1089
1432
exitcode = EXIT_FAILURE;