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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 <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_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 <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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#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
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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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* 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 incbuffer(char **buffer, size_t buffer_length,
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size_t buffer_capacity){
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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();
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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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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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decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
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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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AVAHI_GCC_UNUSED AvahiStringList *txt,
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AVAHI_GCC_UNUSED AvahiLookupResultFlags
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mandos_context *mc = userdata;
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AVAHI_GCC_UNUSED void* 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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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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const char *seckey = PATHDIR "/" SECKEY;
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const char *pubkey = PATHDIR "/" PUBKEY;
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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 = { .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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.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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mc.priority = arg;
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case 131: /* --delay */
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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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delay = strtof(arg, &tmp);
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if(errno != 0 or tmp == arg or *tmp != '\0'){
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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)
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& ~(unsigned int)ARGP_HELP_EXIT_OK);
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case -3: /* --usage */
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argp_state_help(state, state->out_stream,
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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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.doc = "Mandos client -- Get and decrypt"
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" passwords from a Mandos server" };
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ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
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if(ret == ARGP_ERR_UNKNOWN){
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fprintf(stderr, "Unknown error while parsing arguments\n");
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exitcode = EXIT_FAILURE;
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ret = argp_parse(&argp, argc, argv,
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ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
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perror("argp_parse");
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exitcode = EX_OSERR;
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exitcode = EX_USAGE;
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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 = EX_UNAVAILABLE;
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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 = EX_OSERR;
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ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
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perror("sigaddset");
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exitcode = EX_OSERR;
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ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
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perror("sigaddset");
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exitcode = EX_OSERR;
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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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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 = EX_OSERR;
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ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
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perror("sigaction");
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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 = EX_OSERR;
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ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
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perror("sigaction");
1265
if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &sigterm_action, NULL);
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perror("sigaction");
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exitcode = EX_OSERR;
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/* If the interface is down, bring it up */
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if(interface[0] != '\0'){
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if_index = (AvahiIfIndex) if_nametoindex(interface);
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fprintf(stderr, "No such interface: \"%s\"\n", interface);
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exitcode = EX_UNAVAILABLE;
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/* Re-raise priviliges */
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#ifdef __linux__
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/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
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messages to mess up the prompt */
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messages about the network interface to mess up the prompt */
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ret = klogctl(8, NULL, 5);
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bool restore_loglevel = true;
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restore_loglevel = false;
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perror("klogctl");
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#endif /* __linux__ */
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sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
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perror("socket");
1011
exitcode = EXIT_FAILURE;
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exitcode = EX_OSERR;
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1309
#ifdef __linux__
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1310
if(restore_loglevel){
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1311
ret = klogctl(7, NULL, 0);
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1397
perror("klogctl");
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ret = init_gnutls_global(&mc, pubkey, seckey);
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#endif /* __linux__ */
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/* Lower privileges */
1403
if(take_down_interface){
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/* Lower privileges */
1410
/* Lower privileges permanently */
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ret = init_gnutls_global(pubkey, seckey);
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1424
fprintf(stderr, "init_gnutls_global failed\n");
1100
exitcode = EXIT_FAILURE;
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exitcode = EX_UNAVAILABLE;
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1428
gnutls_initialized = true;
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tempdir_created = true;
1106
1436
if(mkdtemp(tempdir) == NULL){
1437
tempdir_created = false;
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1438
perror("mkdtemp");
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1446
if(not init_gpgme(pubkey, seckey, tempdir)){
1113
1447
fprintf(stderr, "init_gpgme failed\n");
1114
exitcode = EXIT_FAILURE;
1448
exitcode = EX_UNAVAILABLE;
1117
1451
gpgme_initialized = true;
1120
if(interface[0] != '\0'){
1121
if_index = (AvahiIfIndex) if_nametoindex(interface);
1123
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1124
exitcode = EXIT_FAILURE;
1129
1458
if(connect_to != NULL){
1200
1551
if(mc.server == NULL){
1201
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fprintf(stderr, "Failed to create Avahi server: %s\n",
1202
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avahi_strerror(error));
1203
exitcode = EXIT_FAILURE;
1554
exitcode = EX_UNAVAILABLE;
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/* Create the Avahi service browser */
1208
1563
sb = avahi_s_service_browser_new(mc.server, if_index,
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1564
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1565
NULL, 0, browse_callback, NULL);
1211
1566
if(sb == NULL){
1212
1567
fprintf(stderr, "Failed to create service browser: %s\n",
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1568
avahi_strerror(avahi_server_errno(mc.server)));
1214
exitcode = EXIT_FAILURE;
1569
exitcode = EX_UNAVAILABLE;