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32
/* 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(), 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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srand(), strtof(), abort() */
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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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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
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getuid(), getgid(), seteuid(),
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getuid(), getgid(), setuid(),
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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_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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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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* 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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* "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 adjustbuffer(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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/* 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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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();
475
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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} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
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ret = gnutls_init(session, GNUTLS_SERVER);
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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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/* 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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mandos_context *mc, int af){
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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 = 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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gnutls_session_t session;
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int pf; /* Protocol family */
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fprintf(stderr, "Closing TLS session\n");
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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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gnutls_bye(session, GNUTLS_SHUT_RDWR);
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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_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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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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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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const char *domain,
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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 new services becomes available on the LAN or
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is removed from the LAN */
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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, protocol,
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name, type, domain, protocol, 0,
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resolve_callback, NULL) == NULL)
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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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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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/* stop main loop after sigterm has been called */
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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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* This function determines if a directory entry in /sys/class/net
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* corresponds to an acceptable network device.
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* (This function is passed to scandir(3) as a filter function.)
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int good_interface(const struct dirent *if_entry){
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char *flagname = NULL;
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int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
993
if(if_entry->d_name[0] == '.'){
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int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
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typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
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/* read line from flags_fd */
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ssize_t to_read = (sizeof(ifreq_flags)*2)+3; /* "0x1003\n" */
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char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
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flagstring[(size_t)to_read] = '\0';
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if(flagstring == NULL){
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ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
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tmpmax = strtoimax(flagstring, &tmp, 0);
1030
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1031
and not (isspace(*tmp)))
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or tmpmax != (ifreq_flags)tmpmax){
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fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
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flagstring, if_entry->d_name);
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ifreq_flags flags = (ifreq_flags)tmpmax;
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/* Reject the loopback device */
1043
if(flags & IFF_LOOPBACK){
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fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
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/* Accept point-to-point devices only if connect_to is specified */
1051
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1053
fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
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/* Otherwise, reject non-broadcast-capable devices */
1059
if(not (flags & IFF_BROADCAST)){
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fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
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/* Accept this device */
1068
fprintf(stderr, "Interface \"%s\" is acceptable\n",
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int main(int argc, char *argv[]){
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AvahiSServiceBrowser *sb = NULL;
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intmax_t tmpmax;
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879
int exitcode = EXIT_SUCCESS;
1081
const char *interface = "";
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const char *interface = "eth0";
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struct ifreq network;
1084
bool take_down_interface = false;
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char *connect_to = NULL;
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char tempdir[] = "/tmp/mandosXXXXXX";
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bool tempdir_created = false;
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AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
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const char *seckey = PATHDIR "/" SECKEY;
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890
const char *pubkey = PATHDIR "/" PUBKEY;
892
mandos_context mc = { .simple_poll = NULL, .server = NULL,
893
.dh_bits = 1024, .priority = "SECURE256"
894
":!CTYPE-X.509:+CTYPE-OPENPGP" };
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bool gnutls_initialized = false;
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bool gpgme_initialized = false;
1097
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
1098
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1103
/* Lower any group privileges we might have, just to be safe */
1110
/* Lower user privileges (temporarily) */
1122
900
struct argp_option options[] = {
1176
954
case 129: /* --dh-bits */
1178
tmpmax = strtoimax(arg, &tmp, 10);
1179
if(errno != 0 or tmp == arg or *tmp != '\0'
1180
or tmpmax != (typeof(mc.dh_bits))tmpmax){
955
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
956
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
957
or arg[numchars] != '\0'){
1181
958
fprintf(stderr, "Bad number of DH bits\n");
1182
959
exit(EXIT_FAILURE);
1220
avahi_set_log_function(empty_log);
1223
if(interface[0] == '\0'){
1224
struct dirent **direntries;
1225
ret = scandir(sys_class_net, &direntries, good_interface,
1228
/* Pick the first good interface */
1229
interface = strdup(direntries[0]->d_name);
1231
fprintf(stderr, "Using interface \"%s\"\n", interface);
1233
if(interface == NULL){
1236
exitcode = EXIT_FAILURE;
1242
fprintf(stderr, "Could not find a network interface\n");
1243
exitcode = EXIT_FAILURE;
1248
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1249
from the signal handler */
1250
/* Initialize the pseudo-RNG for Avahi */
1251
srand((unsigned int) time(NULL));
1252
mc.simple_poll = avahi_simple_poll_new();
1253
if(mc.simple_poll == NULL){
1254
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1255
exitcode = EXIT_FAILURE;
1259
sigemptyset(&sigterm_action.sa_mask);
1260
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1262
perror("sigaddset");
1263
exitcode = EXIT_FAILURE;
1266
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1268
perror("sigaddset");
1269
exitcode = EXIT_FAILURE;
1272
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1274
perror("sigaddset");
1275
exitcode = EXIT_FAILURE;
1278
/* Need to check if the handler is SIG_IGN before handling:
1279
| [[info:libc:Initial Signal Actions]] |
1280
| [[info:libc:Basic Signal Handling]] |
1282
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1284
perror("sigaction");
1285
return EXIT_FAILURE;
1287
if(old_sigterm_action.sa_handler != SIG_IGN){
1288
ret = sigaction(SIGINT, &sigterm_action, NULL);
1290
perror("sigaction");
1291
exitcode = EXIT_FAILURE;
1295
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1297
perror("sigaction");
1298
return EXIT_FAILURE;
1300
if(old_sigterm_action.sa_handler != SIG_IGN){
1301
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1303
perror("sigaction");
1304
exitcode = EXIT_FAILURE;
1308
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1310
perror("sigaction");
1311
return EXIT_FAILURE;
1313
if(old_sigterm_action.sa_handler != SIG_IGN){
1314
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1316
perror("sigaction");
1317
exitcode = EXIT_FAILURE;
1322
995
/* If the interface is down, bring it up */
1323
if(strcmp(interface, "none") != 0){
1324
if_index = (AvahiIfIndex) if_nametoindex(interface);
1326
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1327
exitcode = EXIT_FAILURE;
1335
/* Re-raise priviliges */
996
if(interface[0] != '\0'){
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997
#ifdef __linux__
1343
998
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1344
999
messages to mess up the prompt */
1592
1207
/* Create the Avahi service browser */
1593
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
1594
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1595
NULL, 0, browse_callback, NULL);
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1596
1211
if(sb == NULL){
1597
1212
fprintf(stderr, "Failed to create service browser: %s\n",
1598
1213
avahi_strerror(avahi_server_errno(mc.server)));
1638
1249
gpgme_release(mc.ctx);
1641
/* Take down the network interface */
1642
if(take_down_interface){
1643
/* Re-raise priviliges */
1650
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1652
perror("ioctl SIOCGIFFLAGS");
1653
} else if(network.ifr_flags & IFF_UP) {
1654
network.ifr_flags &= ~IFF_UP; /* clear flag */
1655
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1657
perror("ioctl SIOCSIFFLAGS -IFF_UP");
1660
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1664
/* Lower privileges permanently */
1673
1252
/* Removes the temp directory used by GPGME */
1674
1253
if(tempdir_created){