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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(), 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 <sysexits.h> /* EX_OSERR, EX_USAGE */
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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();
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gnutls_dh_params_deinit(mc.dh_params);
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gnutls_dh_params_deinit(mc->dh_params);
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static int init_gnutls_session(gnutls_session_t *session){
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static int init_gnutls_session(mandos_context *mc,
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gnutls_session_t *session){
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/* GnuTLS session creation */
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ret = gnutls_init(session, GNUTLS_SERVER);
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} 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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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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case 129: /* --dh-bits */
1093
tmpmax = strtoimax(arg, &tmp, 10);
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if(errno != 0 or tmp == arg or *tmp != '\0'
1095
or tmpmax != (typeof(mc.dh_bits))tmpmax){
1096
argp_error(state, "Bad number of DH bits");
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ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
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if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
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or arg[numchars] != '\0'){
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fprintf(stderr, "Bad number of DH bits\n");
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961
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
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mc.priority = arg;
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case 131: /* --delay */
1105
delay = strtof(arg, &tmp);
1106
if(errno != 0 or tmp == arg or *tmp != '\0'){
1107
argp_error(state, "Bad delay");
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
969
fprintf(stderr, "Bad delay\n");
1111
* These reproduce what we would get without ARGP_NO_HELP
1113
case '?': /* --help */
1114
argp_state_help(state, state->out_stream,
1115
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1116
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1117
case -3: /* --usage */
1118
argp_state_help(state, state->out_stream,
1119
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1120
case 'V': /* --version */
1121
fprintf(state->out_stream, "%s\n", argp_program_version);
1122
exit(argp_err_exit_status);
1125
978
return ARGP_ERR_UNKNOWN;
1130
983
struct argp argp = { .options = options, .parser = parse_opt,
1132
985
.doc = "Mandos client -- Get and decrypt"
1133
986
" passwords from a Mandos server" };
1134
ret = argp_parse(&argp, argc, argv,
1135
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1142
perror("argp_parse");
1143
exitcode = EX_OSERR;
1146
exitcode = EX_USAGE;
1152
avahi_set_log_function(empty_log);
1155
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1156
from the signal handler */
1157
/* Initialize the pseudo-RNG for Avahi */
1158
srand((unsigned int) time(NULL));
1159
mc.simple_poll = avahi_simple_poll_new();
1160
if(mc.simple_poll == NULL){
1161
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1162
exitcode = EXIT_FAILURE;
1166
sigemptyset(&sigterm_action.sa_mask);
1167
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1169
perror("sigaddset");
1170
exitcode = EXIT_FAILURE;
1173
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1175
perror("sigaddset");
1176
exitcode = EXIT_FAILURE;
1179
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1181
perror("sigaddset");
1182
exitcode = EXIT_FAILURE;
1185
/* Need to check if the handler is SIG_IGN before handling:
1186
| [[info:libc:Initial Signal Actions]] |
1187
| [[info:libc:Basic Signal Handling]] |
1189
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1191
perror("sigaction");
1192
return EXIT_FAILURE;
1194
if(old_sigterm_action.sa_handler != SIG_IGN){
1195
ret = sigaction(SIGINT, &sigterm_action, NULL);
1197
perror("sigaction");
1198
exitcode = EXIT_FAILURE;
1202
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1204
perror("sigaction");
1205
return EXIT_FAILURE;
1207
if(old_sigterm_action.sa_handler != SIG_IGN){
1208
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1210
perror("sigaction");
1211
exitcode = EXIT_FAILURE;
1215
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1217
perror("sigaction");
1218
return EXIT_FAILURE;
1220
if(old_sigterm_action.sa_handler != SIG_IGN){
1221
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1223
perror("sigaction");
987
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
988
if(ret == ARGP_ERR_UNKNOWN){
989
fprintf(stderr, "Unknown error while parsing arguments\n");
1224
990
exitcode = EXIT_FAILURE;
1229
995
/* If the interface is down, bring it up */
1230
996
if(interface[0] != '\0'){
1231
if_index = (AvahiIfIndex) if_nametoindex(interface);
1233
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1234
exitcode = EXIT_FAILURE;
1242
/* Re-raise priviliges */
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997
#ifdef __linux__
1250
998
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1251
messages about the network interface to mess up the prompt */
999
messages to mess up the prompt */
1252
1000
ret = klogctl(8, NULL, 5);
1253
1001
bool restore_loglevel = true;
1255
1003
restore_loglevel = false;
1256
1004
perror("klogctl");
1258
#endif /* __linux__ */
1260
1008
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1499
1207
/* Create the Avahi service browser */
1500
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
1501
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1502
NULL, 0, browse_callback, NULL);
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1503
1211
if(sb == NULL){
1504
1212
fprintf(stderr, "Failed to create service browser: %s\n",
1505
1213
avahi_strerror(avahi_server_errno(mc.server)));
1545
1249
gpgme_release(mc.ctx);
1548
/* Take down the network interface */
1549
if(take_down_interface){
1550
/* Re-raise priviliges */
1557
ret = ioctl(sd, SIOCGIFFLAGS, &network);
1559
perror("ioctl SIOCGIFFLAGS");
1560
} else if(network.ifr_flags & IFF_UP) {
1561
network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
1562
ret = ioctl(sd, SIOCSIFFLAGS, &network);
1564
perror("ioctl SIOCSIFFLAGS");
1567
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1571
/* Lower privileges permanently */
1580
1252
/* Removes the temp directory used by GPGME */
1581
1253
if(tempdir_created){