/* -- sslhelper.c -- */ #include "x11vnc.h" #include "inet.h" #include "cleanup.h" #include "screen.h" #include "scan.h" #include "connections.h" #define OPENSSL_INETD 1 #define OPENSSL_VNC 2 #define OPENSSL_HTTPS 3 #if LIBVNCSERVER_HAVE_FORK #if LIBVNCSERVER_HAVE_SYS_WAIT_H && LIBVNCSERVER_HAVE_WAITPID #define FORK_OK #endif #endif int openssl_sock = -1; int openssl_port_num = 0; int https_sock = -1; pid_t openssl_last_helper_pid = 0; #if !LIBVNCSERVER_HAVE_LIBSSL int openssl_present(void) {return 0;} void openssl_init(void) { rfbLog("not compiled with libssl support.\n"); clean_up_exit(1); } void openssl_port(void) {} void https_port(void) {} void check_openssl(void) {} void check_https(void) {} void ssl_helper_pid(pid_t pid, int sock) {sock = pid;} void accept_openssl(int mode) {mode = 0; clean_up_exit(1);} #else #include #include #include int openssl_present(void); void openssl_init(void); void openssl_port(void); void check_openssl(void); void check_https(void); void ssl_helper_pid(pid_t pid, int sock); void accept_openssl(int mode); static SSL_CTX *ctx = NULL; static RSA *rsa_512 = NULL; static RSA *rsa_1024 = NULL; static SSL *ssl = NULL; static void init_prng(void); static void sslerrexit(void); static char *create_tmp_pem(void); static int ssl_init(int s_in, int s_out); static void ssl_xfer(int csock, int s_in, int s_out, int is_https); #ifndef FORK_OK void openssl_init(void) { rfbLog("openssl_init: fork is not supported. cannot create" " ssl helper process.\n"); clean_up_exit(1); } int openssl_present(void) {return 0;} #else int openssl_present(void) {return 1;} static void sslerrexit(void) { unsigned long err = ERR_get_error(); char str[256]; if (err) { ERR_error_string(err, str); fprintf(stderr, "ssl error: %s\n", str); } clean_up_exit(1); } /* uses /usr/bin/openssl to create a tmp cert */ static char *create_tmp_pem(void) { pid_t pid, pidw; FILE *in, *out; char cnf[] = "/tmp/x11vnc-cnf.XXXXXX"; char pem[] = "/tmp/x11vnc-pem.XXXXXX"; char str[4096], line[1024], *path, *p, *exe; int found_openssl = 0, cnf_fd, pem_fd, status, show_cert = 1; struct stat sbuf; char tmpl[] = "[ req ]\n" "prompt = no\n" "default_bits = 1024\n" "encrypt_key = yes\n" "distinguished_name = req_dn\n" "x509_extensions = cert_type\n" "\n" "[ req_dn ]\n" "countryName=AU\n" "localityName=%s\n" "organizationalUnitName=%s-%f\n" "organizationName=x11vnc\n" "commonName=x11vnc-SELF-SIGNED-TEMPORARY-CERT-%d\n" "emailAddress=nobody@x11vnc.server\n" "\n" "[ cert_type ]\n" "nsCertType = server\n" ; if (no_external_cmds) { rfbLog("create_tmp_pem: cannot run external commands.\n"); return NULL; } rfbLog("\n"); rfbLog("Creating a temporary, self-signed PEM certificate...\n"); rfbLog("\n"); rfbLog("This will NOT prevent man-in-the-middle attacks UNLESS you\n"); rfbLog("get the certificate information to the VNC viewers SSL\n"); rfbLog("tunnel configuration. However, it will prevent passive\n"); rfbLog("network sniffing.\n"); rfbLog("\n"); rfbLog("The cert inside -----BEGIN CERTIFICATE-----\n"); rfbLog(" ....\n"); rfbLog(" -----END CERTIFICATE-----\n"); rfbLog("printed below may be used on the VNC viewer-side to\n"); rfbLog("authenticate this server for this session. See the -ssl\n"); rfbLog("help output and the FAQ for how to create a permanent\n"); rfbLog("server certificate.\n"); rfbLog("\n"); if (! getenv("PATH")) { return NULL; } path = strdup(getenv("PATH")); /* find openssl binary: */ exe = (char *) malloc(strlen(path) + strlen("/openssl") + 1); p = strtok(path, ":"); while (p) { sprintf(exe, "%s/openssl", p); if (stat(exe, &sbuf) == 0) { if (! S_ISDIR(sbuf.st_mode)) { found_openssl = 1; break; } } p = strtok(NULL, ":"); } free(path); if (! found_openssl) { return NULL; } cnf_fd = mkstemp(cnf); pem_fd = mkstemp(pem); if (cnf_fd < 0 || pem_fd < 0) { return NULL; } close(pem_fd); /* create template file with our made up stuff: */ sprintf(str, tmpl, UT.sysname, UT.nodename, dnow(), (int) getpid()); write(cnf_fd, str, strlen(str)); close(cnf_fd); /* make RSA key */ pid = fork(); if (pid < 0) { return NULL; } else if (pid == 0) { int i; for (i=0; i<256; i++) { close(i); } execlp(exe, exe, "req", "-new", "-x509", "-nodes", "-config", cnf, "-out", pem, "-keyout", pem, (char *)0); exit(1); } pidw = waitpid(pid, &status, 0); if (pidw != pid) { return NULL; } if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { ; } else { return NULL; } /* make DH parameters */ pid = fork(); if (pid < 0) { return NULL; } else if (pid == 0) { int i; for (i=0; i<256; i++) { close(i); } execlp(exe, exe, "dhparam", "-out", cnf, "512", (char *)0); exit(1); } pidw = waitpid(pid, &status, 0); if (pidw != pid) { return NULL; } if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { ; } else { return NULL; } /* append result: */ in = fopen(cnf, "r"); if (in == NULL) { return NULL; } out = fopen(pem, "a"); if (out == NULL) { fclose(in); return NULL; } while (fgets(line, 1024, in) != NULL) { fprintf(out, "%s", line); } fclose(in); fclose(out); unlink(cnf); free(exe); if (show_cert) { char cmd[100]; if (inetd) { sprintf(cmd, "openssl x509 -text -in %s 1>&2", pem); } else { sprintf(cmd, "openssl x509 -text -in %s", pem); } fprintf(stderr, "\n"); system(cmd); fprintf(stderr, "\n"); } return strdup(pem); } void openssl_init(void) { int db = 0, tmp_pem = 0, do_dh = 1; FILE *in; double ds; long mode; if (! quiet) { rfbLog("\n"); rfbLog("Initializing SSL.\n"); } if (db) fprintf(stderr, "\nSSL_load_error_strings()\n"); SSL_load_error_strings(); if (db) fprintf(stderr, "SSL_library_init()\n"); SSL_library_init(); if (db) fprintf(stderr, "init_prng()\n"); init_prng(); ctx = SSL_CTX_new( SSLv23_server_method() ); if (ctx == NULL) { rfbLog("openssl_init: SSL_CTX_new failed.\n"); sslerrexit(); } ds = dnow(); rsa_512 = RSA_generate_key(512,RSA_F4,NULL,NULL); if (rsa_512 == NULL) { rfbLog("openssl_init: RSA_generate_key(512) failed.\n"); sslerrexit(); } rfbLog("created 512 bit temporary RSA key: %.3fs\n", dnow() - ds); ds = dnow(); rsa_1024 = RSA_generate_key(1024,RSA_F4,NULL,NULL); if (rsa_1024 == NULL) { rfbLog("openssl_init: RSA_generate_key(1024) failed.\n"); sslerrexit(); } rfbLog("created 1024 bit temporary RSA key: %.3fs\n", dnow() - ds); if (db) fprintf(stderr, "SSL_CTX_set_tmp_rsa()\n"); if (! SSL_CTX_set_tmp_rsa(ctx, rsa_1024)) { rfbLog("openssl_init: SSL_CTX_set_tmp_rsa(1024) failed.\n"); sslerrexit(); } mode = 0; mode |= SSL_MODE_ENABLE_PARTIAL_WRITE; mode |= SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER; SSL_CTX_set_mode(ctx, mode); SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_BOTH); SSL_CTX_set_timeout(ctx, 300); ds = dnow(); if (! openssl_pem) { openssl_pem = create_tmp_pem(); if (! openssl_pem) { rfbLog("openssl_init: could not create temporary," " self-signed PEM.\n"); clean_up_exit(1); } tmp_pem = 1; } rfbLog("using PEM %s %.3fs\n", openssl_pem, dnow() - ds); if (do_dh) { DH *dh; BIO *bio; ds = dnow(); in = fopen(openssl_pem, "r"); if (in == NULL) { rfbLogPerror("fopen"); clean_up_exit(1); } bio = BIO_new_fp(in, BIO_CLOSE|BIO_FP_TEXT); if (! bio) { rfbLog("openssl_init: BIO_new_fp() failed.\n"); sslerrexit(); } dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL); if (dh == NULL) { rfbLog("openssl_init: PEM_read_bio_DHparams() failed.\n"); BIO_free(bio); sslerrexit(); } BIO_free(bio); SSL_CTX_set_tmp_dh(ctx, dh); rfbLog("loaded Diffie Hellman %d bits, %.3fs\n", 8*DH_size(dh), dnow()-ds); DH_free(dh); } if (! SSL_CTX_use_certificate_chain_file(ctx, openssl_pem)) { rfbLog("openssl_init: SSL_CTX_use_certificate_chain_file() failed.\n"); sslerrexit(); } if(! SSL_CTX_use_RSAPrivateKey_file(ctx, openssl_pem, SSL_FILETYPE_PEM)) { rfbLog("openssl_init: SSL_CTX_set_tmp_rsa(1024) failed.\n"); sslerrexit(); } if (! SSL_CTX_check_private_key(ctx)) { rfbLog("openssl_init: SSL_CTX_set_tmp_rsa(1024) failed.\n"); sslerrexit(); } if (tmp_pem && ! getenv("X11VNC_KEEP_TMP_PEM")) { if (getenv("X11VNC_SHOW_TMP_PEM")) { FILE *in = fopen(openssl_pem, "r"); if (in != NULL) { char line[128]; fprintf(stderr, "\n"); while (fgets(line, 128, in) != NULL) { fprintf(stderr, "%s", line); } fprintf(stderr, "\n"); fclose(in); } } unlink(openssl_pem); free(openssl_pem); } if (ssl_verify) { struct stat sbuf; int lvl; if (stat(ssl_verify, &sbuf) != 0) { rfbLog("openssl_init: -sslverify does not exists %s.\n", ssl_verify); rfbLogPerror("stat"); clean_up_exit(1); } if (! S_ISDIR(sbuf.st_mode)) { if (! SSL_CTX_load_verify_locations(ctx, ssl_verify, NULL)) { rfbLog("openssl_init: SSL_CTX_load_verify_" "locations() failed.\n"); sslerrexit(); } } else { if (! SSL_CTX_load_verify_locations(ctx, NULL, ssl_verify)) { rfbLog("openssl_init: SSL_CTX_load_verify_" "locations() failed.\n"); sslerrexit(); } } lvl = SSL_VERIFY_FAIL_IF_NO_PEER_CERT|SSL_VERIFY_PEER; SSL_CTX_set_verify(ctx, lvl, NULL); } else { SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL); } rfbLog("\n"); } void openssl_port(void) { int sock, shutdown = 0; static int port = 0; static in_addr_t iface = INADDR_ANY; int db = 0; if (! screen) { rfbLog("openssl_port: no screen!\n"); clean_up_exit(1); } if (inetd) { ssl_initialized = 1; return; } if (screen->listenSock > -1 && screen->port > 0) { port = screen->port; shutdown = 1; } if (screen->listenInterface) { iface = screen->listenInterface; } if (shutdown) { if (db) fprintf(stderr, "shutting down %d/%d\n", port, screen->listenSock); rfbShutdownSockets(screen); } sock = rfbListenOnTCPPort(port, iface); if (sock < 0) { rfbLog("openssl_port: could not reopen port %d\n", port); clean_up_exit(1); } if (db) fprintf(stderr, "listen on port/sock %d/%d\n", port, sock); openssl_sock = sock; openssl_port_num = port; ssl_initialized = 1; } void https_port(void) { int sock; static int port = 0; static in_addr_t iface = INADDR_ANY; int db = 0; /* as openssl_port above: open a listening socket for pure https: */ if (https_port_num < 0) { return; } if (! screen) { rfbLog("https_port: no screen!\n"); clean_up_exit(1); } if (screen->listenInterface) { iface = screen->listenInterface; } if (https_port_num == 0) { https_port_num = find_free_port(5801, 5851); } if (https_port_num <= 0) { rfbLog("https_port: could not find port %d\n", https_port_num); clean_up_exit(1); } port = https_port_num; sock = rfbListenOnTCPPort(port, iface); if (sock < 0) { rfbLog("https_port: could not open port %d\n", port); clean_up_exit(1); } if (db) fprintf(stderr, "https_port: listen on port/sock %d/%d\n", port, sock); https_sock = sock; } static void lose_ram(void) { /* * for a forked child that will be around for a long time * without doing exec(). we really should re-exec, but a pain * to redo all SSL ctx. */ free_old_fb(main_fb, rfb_fb, cmap8to24_fb); main_fb = NULL; rfb_fb = NULL; cmap8to24_fb = NULL; if (snap_fb) { free(snap_fb); snap_fb = NULL; } if (raw_fb) { free(raw_fb); raw_fb = NULL; } free_tiles(); } /* utility to keep track of existing helper processes: */ void ssl_helper_pid(pid_t pid, int sock) { # define HPSIZE 256 static pid_t helpers[HPSIZE]; static int sockets[HPSIZE], first = 1; int i, empty, set, status, db = 0; if (first) { for (i=0; i < HPSIZE; i++) { helpers[i] = 0; sockets[i] = 0; } first = 0; } if (pid == 0) { /* killall */ for (i=0; i < HPSIZE; i++) { if (helpers[i] == 0) { sockets[i] = -1; continue; } if (kill(helpers[i], 0) == 0) { if (sock != -2) { if (sockets[i] >= 0) { close(sockets[i]); } kill(helpers[i], SIGTERM); } #if LIBVNCSERVER_HAVE_SYS_WAIT_H && LIBVNCSERVER_HAVE_WAITPID if (db) fprintf(stderr, "waitpid(%d)\n", helpers[i]); waitpid(helpers[i], &status, WNOHANG); #endif if (sock == -2) { continue; } } helpers[i] = 0; sockets[i] = -1; } return; } if (db) fprintf(stderr, "ssl_helper_pid(%d, %d)\n", pid, sock); /* add (or delete for sock == -1) */ set = 0; empty = -1; for (i=0; i < HPSIZE; i++) { if (helpers[i] == pid) { if (sock == -1) { #if LIBVNCSERVER_HAVE_SYS_WAIT_H && LIBVNCSERVER_HAVE_WAITPID if (db) fprintf(stderr, "waitpid(%d) 2\n", helpers[i]); waitpid(helpers[i], &status, WNOHANG); #endif helpers[i] = 0; } sockets[i] = sock; set = 1; } else if (empty == -1 && helpers[i] == 0) { empty = i; } } if (set || sock == -1) { return; /* done */ } /* now try to store */ if (empty >= 0) { helpers[empty] = pid; sockets[empty] = sock; return; } for (i=0; i < HPSIZE; i++) { if (helpers[i] == 0) { continue; } /* clear out stale pids: */ if (kill(helpers[i], 0) != 0) { helpers[i] = 0; sockets[i] = -1; if (empty == -1) { empty = i; } } } if (empty >= 0) { helpers[empty] = pid; sockets[empty] = sock; } } static int is_ssl_readable(int s_in, time_t last_https, char *last_get, int mode) { int nfd, db = 0; struct timeval tv; fd_set rd; /* * we'll do a select() on s_in for reading. this is not an * absolute proof that SSL_read is ready (XXX use SSL utility). */ tv.tv_sec = 2; tv.tv_usec = 0; if (mode == OPENSSL_INETD) { /* * https via inetd is icky because x11vnc is restarted * for each socket (and some clients send requests * rapid fire). */ tv.tv_sec = 6; } /* * increase the timeout if we know HTTP traffic has occurred * recently: */ if (time(0) < last_https + 30) { tv.tv_sec = 8; if (strstr(last_get, "VncViewer")) { tv.tv_sec = 4; } } FD_ZERO(&rd); FD_SET(s_in, &rd); do { nfd = select(s_in+1, &rd, NULL, NULL, &tv); } while (nfd < 0 && errno == EINTR); if (db) fprintf(stderr, "https nfd: %d\n", nfd); if (nfd <= 0 || ! FD_ISSET(s_in, &rd)) { return 0; } return 1; } #define BSIZE 16384 static int watch_for_http_traffic(char **buf_a, int *n_a) { int is_http, err, n, n2; char *buf = *buf_a; int db = 0; /* * sniff the first couple bytes of the stream and try to see * if it is http or not. if we read them OK, we must read the * rest of the available data otherwise we may deadlock. * what has be read is returned in buf_a and n_a. * *buf_a is BSIZE+1 long and zeroed. */ *n_a = 0; n = SSL_read(ssl, buf, 2); err = SSL_get_error(ssl, n); if (err != SSL_ERROR_NONE || n < 2) { if (n > 0) { *n_a = n; } return -1; } /* look for GET, HEAD, POST, CONNECT */ is_http = 0; if (!strncmp("GE", buf, 2)) { is_http = 1; } else if (!strncmp("HE", buf, 2)) { is_http = 1; } else if (!strncmp("PO", buf, 2)) { is_http = 1; } else if (!strncmp("CO", buf, 2)) { is_http = 1; } if (db) fprintf(stderr, "read: '%s'\n", buf); /* * better read all we can and fwd it along to avoid blocking * in ssl_xfer(). */ n2 = SSL_read(ssl, buf + n, BSIZE - n); if (n2 >= 0) { n += n2; } *n_a = n; return is_http; } static int csock_timeout_sock = -1; static void csock_timeout (int sig) { rfbLog("sig: %d, csock_timeout.\n", sig); if (csock_timeout_sock >= 0) { close(csock_timeout_sock); csock_timeout_sock = -1; } } void accept_openssl(int mode) { int sock = -1, cport, csock, vsock; int status, n, i, db = 0; struct sockaddr_in addr; socklen_t addrlen = sizeof(addr); char cookie[128], rcookie[128], *name; rfbClientPtr client; pid_t pid; char uniq[] = "__evilrats__"; static time_t last_https = 0; static char last_get[128]; static int first = 1; openssl_last_helper_pid = 0; /* zero buffers for use below. */ for (i=0; i<128; i++) { if (first) { last_get[i] = '\0'; } cookie[i] = '\0'; rcookie[i] = '\0'; } first = 0; /* do INETD, VNC, or HTTPS cases (result is client socket or pipe) */ if (mode == OPENSSL_INETD) { ssl_initialized = 1; } else if (mode == OPENSSL_VNC && openssl_sock >= 0) { sock = accept(openssl_sock, (struct sockaddr *)&addr, &addrlen); if (sock < 0) { rfbLog("SSL: accept_openssl: accept connection failed\n"); rfbLogPerror("accept"); return; } } else if (mode == OPENSSL_HTTPS && https_sock >= 0) { sock = accept(https_sock, (struct sockaddr *)&addr, &addrlen); if (sock < 0) { rfbLog("SSL: accept_openssl: accept connection failed\n"); rfbLogPerror("accept"); return; } } if (db) fprintf(stderr, "SSL: accept_openssl: sock: %d\n", sock); /* now make a listening socket for child to connect back to us by: */ cport = find_free_port(20000, 0); if (! cport) { rfbLog("SSL: accept_openssl: could not find open port.\n"); close(sock); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } if (db) fprintf(stderr, "accept_openssl: cport: %d\n", cport); csock = rfbListenOnTCPPort(cport, htonl(INADDR_LOOPBACK)); if (csock < 0) { rfbLog("SSL: accept_openssl: could not listen on port %d.\n", cport); close(sock); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } if (db) fprintf(stderr, "accept_openssl: csock: %d\n", csock); fflush(stderr); /* * make a simple cookie to id the child socket, not foolproof * but hard to guess exactly (just worrying about local lusers * here, since we use INADDR_LOOPBACK). */ sprintf(cookie, "%f/%f", dnow(), x11vnc_start); if (mode != OPENSSL_INETD) { name = get_remote_host(sock); } else { name = strdup("inetd-connection"); } if (name) { rfbLog("SSL: spawning helper process to handle: %s\n", name); free(name); } /* now fork the child to handle the SSL: */ pid = fork(); if (pid < 0) { rfbLog("SSL: accept_openssl: could not fork.\n"); rfbLogPerror("fork"); close(sock); close(csock); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } else if (pid == 0) { int s_in, s_out, httpsock = -1; int vncsock, sslsock = sock; int i, have_httpd = 0; int f_in = fileno(stdin); int f_out = fileno(stdout); /* reset all handlers to default (no interrupted() calls) */ signal(SIGHUP, SIG_DFL); signal(SIGINT, SIG_DFL); signal(SIGQUIT, SIG_DFL); signal(SIGTERM, SIG_DFL); /* close all non-essential fd's */ for (i=0; i<256; i++) { if (i != sslsock && i != 2) { if (mode == OPENSSL_INETD) { if (i == f_in || i == f_out) { continue; } } close(i); } } /* * sadly, we are a long lived child and so the large * framebuffer memory areas will soon differ from parent. * try to free as much as possible. */ lose_ram(); /* now connect back to parent socket: */ vncsock = rfbConnectToTcpAddr("127.0.0.1", cport); if (vncsock < 0) { close(vncsock); exit(1); } /* try to initialize SSL with the remote client */ if (mode == OPENSSL_INETD) { s_in = fileno(stdin); s_out = fileno(stdout); } else { s_in = s_out = sock; } if (! ssl_init(s_in, s_out)) { close(vncsock); exit(1); } /* * things get messy below since we are trying to do * *both* VNC and Java applet httpd through the same * SSL socket. */ if (screen->httpListenSock >= 0 && screen->httpPort > 0) { have_httpd = 1; } if (mode == OPENSSL_HTTPS && ! have_httpd) { rfbLog("SSL: accept_openssl: no httpd socket for " "-https mode\n"); close(vncsock); exit(1); } if (have_httpd) { int n, is_http; int hport = screen->httpPort; char *iface = NULL; static char *buf = NULL; if (buf == NULL) { buf = (char *) calloc(sizeof(BSIZE+1), 1); } if (mode == OPENSSL_HTTPS) { /* * for this mode we know it is HTTP traffic * so we skip trying to guess. */ is_http = 1; n = 0; goto connect_to_httpd; } /* * Check if there is stuff to read from remote end * if so it is likely a GET or HEAD. */ if (! is_ssl_readable(s_in, last_https, last_get, mode)) { goto write_cookie; } /* * read first 2 bytes to try to guess. sadly, * the user is often pondering a "non-verified * cert" dialog for a long time before the GET * is ever sent. So often we timeout here. */ is_http = watch_for_http_traffic(&buf, &n); if (is_http < 0 || is_http == 0) { /* * error or http not detected, fall back * to normal VNC socket. */ write(vncsock, cookie, strlen(cookie)); if (n > 0) { write(vncsock, buf, n); } goto wrote_cookie; } connect_to_httpd: /* * Here we go... no turning back. we have to * send failure to parent and close socket to have * http processed at all in a timely fashion... */ /* send the failure tag: */ write(vncsock, uniq, strlen(uniq)); if (strstr(buf, "HTTP/") != NULL) { /* * Also send back the GET line for heuristics. * (last_https, get file). */ char *q, *str = strdup(buf); q = strstr(str, "HTTP/"); if (q != NULL) { *q = '\0'; write(vncsock, str, strlen(str)); } free(str); } /* * Also send the cookie to pad out the number of * bytes to more than the parent wants to read. * Since this is the failure case, it does not * matter that we send more than strlen(cookie). */ write(vncsock, cookie, strlen(cookie)); usleep(150*1000); close(vncsock); /* now, finally, connect to the libvncserver httpd: */ if (screen->listenInterface == htonl(INADDR_ANY) || screen->listenInterface == htonl(INADDR_NONE)) { iface = "127.0.0.1"; } else { struct in_addr in; in.s_addr = screen->listenInterface; iface = inet_ntoa(in); } if (iface == NULL || !strcmp(iface, "")) { iface = "127.0.0.1"; } usleep(150*1000); httpsock = rfbConnectToTcpAddr(iface, hport); if (httpsock < 0) { /* UGH, after all of that! */ rfbLog("Could not connect to httpd socket!\n"); exit(1); } if (db) fprintf(stderr, "ssl_helper: httpsock: %d %d\n", httpsock, n); /* * send what we read to httpd, and then connect * the rest of the SSL session to it: */ if (n > 0) { write(httpsock, buf, n); } ssl_xfer(httpsock, s_in, s_out, is_http); exit(0); } /* * ok, back from the above https mess, simply send the * cookie back to the parent (who will attach us to * libvncserver), and connect the rest of the SSL session * to it. */ write_cookie: write(vncsock, cookie, strlen(cookie)); wrote_cookie: ssl_xfer(vncsock, s_in, s_out, 0); exit(0); } if (mode != OPENSSL_INETD) { close(sock); } if (db) fprintf(stderr, "helper process is: %d\n", pid); /* accept connection from our child. */ signal(SIGALRM, csock_timeout); csock_timeout_sock = csock; alarm(20); vsock = accept(csock, (struct sockaddr *)&addr, &addrlen); alarm(0); signal(SIGALRM, SIG_DFL); close(csock); if (vsock < 0) { rfbLog("SSL: accept_openssl: connection from ssl_helper failed.\n"); rfbLogPerror("accept"); kill(pid, SIGTERM); waitpid(pid, &status, WNOHANG); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } if (db) fprintf(stderr, "accept_openssl: vsock: %d\n", vsock); n = read(vsock, rcookie, strlen(cookie)); if (n != (int) strlen(cookie) || strncmp(cookie, rcookie, n)) { rfbLog("SSL: accept_openssl: cookie from ssl_helper failed. %d\n", n); if (errno != 0) { rfbLogPerror("read"); } if (db) fprintf(stderr, "'%s'\n'%s'\n", cookie, rcookie); close(vsock); if (strstr(rcookie, uniq) == rcookie) { int i; rfbLog("SSL: https for helper process succeeded.\n"); if (mode != OPENSSL_HTTPS) { last_https = time(0); for (i=0; i<128; i++) { last_get[i] = '\0'; } strncpy(last_get, rcookie, 100); if (db) fprintf(stderr, "last_get: '%s'\n", last_get); } ssl_helper_pid(pid, -2); if (mode == OPENSSL_INETD) { /* to expand $PORT correctly in index.vnc */ if (screen->port == 0) { int fd = fileno(stdin); if (getenv("X11VNC_INETD_PORT")) { screen->port = atoi(getenv( "X11VNC_INETD_PORT")); } else { int tport = get_local_port(fd); if (tport > 0) { screen->port = tport; } } } rfbLog("SSL: screen->port %d\n", screen->port); /* kludge for https fetch via inetd */ double start = dnow(); while (dnow() < start + 10.0) { rfbPE(10000); usleep(10000); waitpid(pid, &status, WNOHANG); if (kill(pid, 0) != 0) { rfbPE(10000); rfbPE(10000); break; } } rfbLog("SSL: OPENSSL_INETD guessing " "child https finished.\n"); clean_up_exit(1); } return; } kill(pid, SIGTERM); waitpid(pid, &status, WNOHANG); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } if (db) fprintf(stderr, "accept_openssl: cookie good: %s\n", cookie); rfbLog("SSL: handshake with helper process succeeded.\n"); openssl_last_helper_pid = pid; ssl_helper_pid(pid, vsock); client = rfbNewClient(screen, vsock); openssl_last_helper_pid = 0; if (client) { if (db) fprintf(stderr, "accept_openssl: client %p\n", (void *) client); if (db) fprintf(stderr, "accept_openssl: new_client %p\n", (void *) screen->newClientHook); if (db) fprintf(stderr, "accept_openssl: new_client %p\n", (void *) new_client); if (mode == OPENSSL_INETD) { inetd_client = client; client->clientGoneHook = client_gone; } } else { rfbLog("SSL: accept_openssl: rfbNewClient failed.\n"); close(vsock); kill(pid, SIGTERM); waitpid(pid, &status, WNOHANG); if (mode == OPENSSL_INETD) { clean_up_exit(1); } return; } } static void ssl_timeout (int sig) { rfbLog("sig: %d, ssl_init timed out.\n", sig); exit(1); } static int ssl_init(int s_in, int s_out) { unsigned char *sid = (unsigned char *) "x11vnc SID"; char *name; int db = 0, rc, err; int ssock = s_in; double start = dnow(); int timeout = 20; if (db) fprintf(stderr, "ssl_init: %d/%d\n", s_in, s_out); ssl = SSL_new(ctx); if (ssl == NULL) { fprintf(stderr, "SSL_new failed\n"); return 0; } SSL_set_session_id_context(ssl, sid, strlen((char *)sid)); if (s_in == s_out) { if (! SSL_set_fd(ssl, ssock)) { fprintf(stderr, "SSL_set_fd failed\n"); return 0; } } else { if (! SSL_set_rfd(ssl, s_in)) { fprintf(stderr, "SSL_set_rfd failed\n"); return 0; } if (! SSL_set_wfd(ssl, s_out)) { fprintf(stderr, "SSL_set_wfd failed\n"); return 0; } } SSL_set_accept_state(ssl); name = get_remote_host(ssock); while (1) { if (db) fprintf(stderr, "calling SSL_accept...\n"); signal(SIGALRM, ssl_timeout); alarm(timeout); rc = SSL_accept(ssl); err = SSL_get_error(ssl, rc); alarm(0); signal(SIGALRM, SIG_DFL); if (db) fprintf(stderr, "SSL_accept %d/%d\n", rc, err); if (err == SSL_ERROR_NONE) { break; } else if (err == SSL_ERROR_WANT_READ) { if (db) fprintf(stderr, "got SSL_ERROR_WANT_READ\n"); rfbLog("SSL: ssl_helper: SSL_accept() failed for: %s\n", name); return 0; } else if (err == SSL_ERROR_WANT_WRITE) { if (db) fprintf(stderr, "got SSL_ERROR_WANT_WRITE\n"); rfbLog("SSL: ssl_helper: SSL_accept() failed for: %s\n", name); return 0; } else if (err == SSL_ERROR_SYSCALL) { if (db) fprintf(stderr, "got SSL_ERROR_SYSCALL\n"); rfbLog("SSL: ssl_helper: SSL_accept() failed for: %s\n", name); return 0; } else if (err == SSL_ERROR_ZERO_RETURN) { if (db) fprintf(stderr, "got SSL_ERROR_ZERO_RETURN\n"); rfbLog("SSL: ssl_helper: SSL_accept() failed for: %s\n", name); return 0; } else if (rc < 0) { rfbLog("SSL: ssl_helper: SSL_accept() fatal: %d\n", rc); return 0; } else if (dnow() > start + 3.0) { rfbLog("SSL: ssl_helper: timeout looping SSL_accept() " "fatal.\n"); return 0; } else { BIO *bio = SSL_get_rbio(ssl); if (bio == NULL) { rfbLog("SSL: ssl_helper: ssl BIO is null. " "fatal.\n"); return 0; } if (BIO_eof(bio)) { rfbLog("SSL: ssl_helper: ssl BIO is EOF. " "fatal.\n"); return 0; } } usleep(10 * 1000); } rfbLog("SSL: ssl_helper: SSL_accept() succeeded for: %s\n", name); free(name); return 1; } static void ssl_xfer_debug(int csock, int s_in, int s_out) { char buf[2048]; int sz = 2048, n, m, status; pid_t pid = fork(); int db = 1; /* this is for testing, no SSL just socket redir */ if (pid < 0) { exit(1); } if (pid) { if (db) fprintf(stderr, "ssl_xfer start: %d -> %d/%d\n", csock, s_in, s_out); while (1) { n = read(csock, buf, sz); if (n == 0 || (n < 0 && errno != EINTR) ) { break; } else if (n > 0) { m = write(s_out, buf, n); if (m != n) { if (db) fprintf(stderr, "ssl_xfer bad write: %d -> %d | %d/%d\n", csock, s_out, m, n); break; } } } kill(pid, SIGTERM); waitpid(pid, &status, WNOHANG); if (db) fprintf(stderr, "ssl_xfer done: %d -> %d\n", csock, s_out); } else { if (db) fprintf(stderr, "ssl_xfer start: %d <- %d\n", csock, s_in); while (1) { n = read(s_in, buf, sz); if (n == 0 || (n < 0 && errno != EINTR) ) { break; } else if (n > 0) { m = write(csock, buf, n); if (m != n) { if (db) fprintf(stderr, "ssl_xfer bad write: %d <- %d | %d/%d\n", csock, s_in, m, n); break; } } } if (db) fprintf(stderr, "ssl_xfer done: %d <- %d\n", csock, s_in); } close(csock); close(s_in); close(s_out); exit(0); } static void ssl_xfer(int csock, int s_in, int s_out, int is_https) { int dbxfer = 0, db = 0, check_pending, fdmax, nfd, n, i, err; char cbuf[BSIZE], sbuf[BSIZE]; int cptr, sptr, c_rd, c_wr, s_rd, s_wr; fd_set rd, wr; struct timeval tv; int ssock; if (dbxfer) { ssl_xfer_debug(csock, s_in, s_out); return; } /* * csock: clear text socket with libvncserver. "C" * ssock: ssl data socket with remote vnc viewer. "S" * * to cover inetd mode, we have s_in and s_out, but in non-ssl mode they * both ssock. * * cbuf[] is data from csock that we have read but not passed on to ssl * sbuf[] is data from ssl that we have read but not passed on to csock */ for (i=0; i s_in) { ssock = s_out; } else { ssock = s_in; } if (csock > ssock) { fdmax = csock; } else { fdmax = ssock; } c_rd = 1; /* clear text (libvncserver) socket open for reading */ c_wr = 1; /* clear text (libvncserver) socket open for writing */ s_rd = 1; /* ssl data (remote client) socket open for reading */ s_wr = 1; /* ssl data (remote client) socket open for writing */ cptr = 0; /* offsets into BSIZE buffers */ sptr = 0; while (1) { int c_to_s, s_to_c; if ( s_wr && (c_rd || cptr > 0) ) { /* * S is writable and * C is readable or some cbuf data remaining */ c_to_s = 1; } else { c_to_s = 0; } if ( c_wr && (s_rd || sptr > 0) ) { /* * C is writable and * S is readable or some sbuf data remaining */ s_to_c = 1; } else { s_to_c = 0; } if (! c_to_s && ! s_to_c) { /* * nothing can be sent either direction. * break out of the loop to finish all work. */ break; } /* set up the fd sets for the two sockets for read & write: */ FD_ZERO(&rd); if (c_rd && cptr < BSIZE) { /* we could read more from C since cbuf is not full */ FD_SET(csock, &rd); } if (s_rd) { /* * we could read more from S since sbuf not full, * OR ssl is waiting for more BIO to be able to * read and we have some C data still buffered. */ if (sptr < BSIZE || (cptr > 0 && SSL_want_read(ssl))) { FD_SET(s_in, &rd); } } FD_ZERO(&wr); if (c_wr && sptr > 0) { /* we could write more to C since sbuf is not empty */ FD_SET(csock, &wr); } if (s_wr) { /* * we could write more to S since cbuf not empty, * OR ssl is waiting for more BIO to be able * write and we haven't filled up sbuf yet. */ if (cptr > 0 || (sptr < BSIZE && SSL_want_write(ssl))) { FD_SET(s_out, &wr); } } if (is_https) { tv.tv_sec = 45; } else { tv.tv_sec = 20; } tv.tv_usec = 0; /* do the select, repeat if interrupted */ do { nfd = select(fdmax+1, &rd, &wr, NULL, &tv); } while (nfd < 0 && errno == EINTR); if (db) fprintf(stderr, "nfd: %d\n", nfd); if (nfd < 0) { rfbLog("SSL: ssl_xfer[%d]: select error: %d\n", getpid(), nfd); perror("select"); /* connection finished */ return; } if (nfd == 0) { rfbLog("SSL: ssl_xfer[%d]: connection timedout.\n", getpid()); /* connection finished */ return; } /* used to see if SSL_pending() should be checked: */ check_pending = 0; if (c_wr && FD_ISSET(csock, &wr)) { /* try to write some of our sbuf to C: */ n = write(csock, sbuf, sptr); if (n < 0) { if (errno != EINTR) { /* connection finished */ return; } /* proceed */ } else if (n == 0) { /* connection finished XXX double check */ return; } else { /* shift over the data in sbuf by n */ memmove(sbuf, sbuf + n, sptr - n); if (sptr == BSIZE) { check_pending = 1; } sptr -= n; if (! s_rd && sptr == 0) { /* finished sending last of sbuf */ shutdown(csock, SHUT_WR); c_wr = 0; } } } if (s_wr) { if ((cptr > 0 && FD_ISSET(s_out, &wr)) || (SSL_want_read(ssl) && FD_ISSET(s_in, &rd))) { /* try to write some of our cbuf to S: */ n = SSL_write(ssl, cbuf, cptr); err = SSL_get_error(ssl, n); if (err == SSL_ERROR_NONE) { /* shift over the data in cbuf by n */ memmove(cbuf, cbuf + n, cptr - n); cptr -= n; if (! c_rd && cptr == 0 && s_wr) { /* finished sending last cbuf */ SSL_shutdown(ssl); s_wr = 0; } } else if (err == SSL_ERROR_WANT_WRITE || err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_X509_LOOKUP) { ; /* proceed */ } else if (err == SSL_ERROR_SYSCALL) { if (n < 0 && errno != EINTR) { /* connection finished */ return; } /* proceed */ } else if (err == SSL_ERROR_ZERO_RETURN) { /* S finished */ s_rd = 0; s_wr = 0; } else if (err == SSL_ERROR_SSL) { /* connection finished */ return; } } } if (c_rd && FD_ISSET(csock, &rd)) { /* try to read some data from C into our cbuf */ n = read(csock, cbuf + cptr, BSIZE - cptr); if (n < 0) { if (errno != EINTR) { /* connection finished */ return; } /* proceed */ } else if (n == 0) { /* C is EOF */ c_rd = 0; if (cptr == 0 && s_wr) { /* and no more in cbuf to send */ SSL_shutdown(ssl); s_wr = 0; } } else { /* good */ cptr += n; } } if (s_rd) { if ((sptr < BSIZE && FD_ISSET(s_in, &rd)) || (SSL_want_write(ssl) && FD_ISSET(s_out, &wr)) || (check_pending && SSL_pending(ssl))) { /* try to read some data from S into our sbuf */ n = SSL_read(ssl, sbuf + sptr, BSIZE - sptr); err = SSL_get_error(ssl, n); if (err == SSL_ERROR_NONE) { /* good */ sptr += n; } else if (err == SSL_ERROR_WANT_WRITE || err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_X509_LOOKUP) { ; /* proceed */ } else if (err == SSL_ERROR_SYSCALL) { if (n < 0) { if(errno != EINTR) { /* connection finished */ return; } /* proceed */ } else { /* S finished */ s_rd = 0; s_wr = 0; } } else if (err == SSL_ERROR_ZERO_RETURN) { /* S is EOF */ s_rd = 0; if (cptr == 0 && s_wr) { /* and no more in cbuf to send */ SSL_shutdown(ssl); s_wr = 0; } if (sptr == 0 && c_wr) { /* and no more in sbuf to send */ shutdown(csock, SHUT_WR); c_wr = 0; } } else if (err == SSL_ERROR_SSL) { /* connection finished */ return; } } } } } void check_openssl(void) { fd_set fds; struct timeval tv; int nfds; static time_t last_waitall = 0; static double last_check = 0.0; double now; if (! use_openssl || openssl_sock < 0) { return; } now = dnow(); if (now < last_check + 0.5) { return; } last_check = now; if (time(0) > last_waitall + 150) { last_waitall = time(0); ssl_helper_pid(0, -2); /* waitall */ } FD_ZERO(&fds); FD_SET(openssl_sock, &fds); tv.tv_sec = 0; tv.tv_usec = 0; nfds = select(openssl_sock+1, &fds, NULL, NULL, &tv); if (nfds <= 0) { return; } rfbLog("SSL: accept_openssl(OPENSSL_VNC)\n"); accept_openssl(OPENSSL_VNC); } void check_https(void) { fd_set fds; struct timeval tv; int nfds; static double last_check = 0.0; double now; if (! use_openssl || https_sock < 0) { return; } now = dnow(); if (now < last_check + 0.5) { return; } last_check = now; FD_ZERO(&fds); FD_SET(https_sock, &fds); tv.tv_sec = 0; tv.tv_usec = 0; nfds = select(https_sock+1, &fds, NULL, NULL, &tv); if (nfds <= 0) { return; } rfbLog("SSL: accept_openssl(OPENSSL_HTTPS)\n"); accept_openssl(OPENSSL_HTTPS); } #define MSZ 4096 static void init_prng(void) { int db = 0, bytes; char file[MSZ]; RAND_file_name(file, MSZ); rfbLog("RAND_file_name: %s\n", file); bytes = RAND_load_file(file, -1); if (db) fprintf(stderr, "bytes read: %d\n", bytes); bytes += RAND_load_file("/dev/urandom", 64); if (db) fprintf(stderr, "bytes read: %d\n", bytes); if (bytes > 0) { if (! quiet) { rfbLog("initialized PRNG with %d random bytes.\n", bytes); } return; } bytes += RAND_load_file("/dev/random", 8); if (db) fprintf(stderr, "bytes read: %d\n", bytes); if (! quiet) { rfbLog("initialized PRNG with %d random bytes.\n", bytes); } } #endif /* FORK_OK */ #endif /* LIBVNCSERVER_HAVE_LIBSSL */