| /* |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| */ |
| /* |
| * SSH2 support by Markus Friedl. |
| * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| */ |
| |
| #include "includes.h" |
| RCSID("$OpenBSD: session.c,v 1.6 2000/04/27 15:23:02 markus Exp $"); |
| |
| #include "xmalloc.h" |
| #include "ssh.h" |
| #include "pty.h" |
| #include "packet.h" |
| #include "buffer.h" |
| #include "cipher.h" |
| #include "mpaux.h" |
| #include "servconf.h" |
| #include "uidswap.h" |
| #include "compat.h" |
| #include "channels.h" |
| #include "nchan.h" |
| |
| #include "bufaux.h" |
| #include "ssh2.h" |
| #include "auth.h" |
| |
| /* types */ |
| |
| #define TTYSZ 64 |
| typedef struct Session Session; |
| struct Session { |
| int used; |
| int self; |
| struct passwd *pw; |
| pid_t pid; |
| /* tty */ |
| char *term; |
| int ptyfd, ttyfd, ptymaster; |
| int row, col, xpixel, ypixel; |
| char tty[TTYSZ]; |
| /* X11 */ |
| char *display; |
| int screen; |
| char *auth_proto; |
| char *auth_data; |
| /* proto 2 */ |
| int chanid; |
| }; |
| |
| /* func */ |
| |
| Session *session_new(void); |
| void session_set_fds(Session *s, int fdin, int fdout, int fderr); |
| void session_pty_cleanup(Session *s); |
| void do_exec_pty(Session *s, const char *command, struct passwd * pw); |
| void do_exec_no_pty(Session *s, const char *command, struct passwd * pw); |
| |
| void |
| do_child(const char *command, struct passwd * pw, const char *term, |
| const char *display, const char *auth_proto, |
| const char *auth_data, const char *ttyname); |
| |
| /* import */ |
| extern ServerOptions options; |
| #ifdef HAVE___PROGNAME |
| extern char *__progname; |
| #else /* HAVE___PROGNAME */ |
| const char *__progname = "sshd"; |
| #endif /* HAVE___PROGNAME */ |
| |
| extern int log_stderr; |
| extern int debug_flag; |
| |
| /* Local Xauthority file. */ |
| static char *xauthfile; |
| |
| /* data */ |
| #define MAX_SESSIONS 10 |
| Session sessions[MAX_SESSIONS]; |
| |
| /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ |
| int no_port_forwarding_flag = 0; |
| int no_agent_forwarding_flag = 0; |
| int no_x11_forwarding_flag = 0; |
| int no_pty_flag = 0; |
| |
| /* RSA authentication "command=" option. */ |
| char *forced_command = NULL; |
| |
| /* RSA authentication "environment=" options. */ |
| struct envstring *custom_environment = NULL; |
| |
| /* |
| * Remove local Xauthority file. |
| */ |
| void |
| xauthfile_cleanup_proc(void *ignore) |
| { |
| debug("xauthfile_cleanup_proc called"); |
| |
| if (xauthfile != NULL) { |
| char *p; |
| unlink(xauthfile); |
| p = strrchr(xauthfile, '/'); |
| if (p != NULL) { |
| *p = '\0'; |
| rmdir(xauthfile); |
| } |
| xfree(xauthfile); |
| xauthfile = NULL; |
| } |
| } |
| |
| /* |
| * Function to perform cleanup if we get aborted abnormally (e.g., due to a |
| * dropped connection). |
| */ |
| void |
| pty_cleanup_proc(void *session) |
| { |
| Session *s=session; |
| if (s == NULL) |
| fatal("pty_cleanup_proc: no session"); |
| debug("pty_cleanup_proc: %s", s->tty); |
| |
| if (s->pid != 0) { |
| /* Record that the user has logged out. */ |
| record_logout(s->pid, s->tty); |
| } |
| |
| /* Release the pseudo-tty. */ |
| pty_release(s->tty); |
| } |
| |
| /* |
| * Prepares for an interactive session. This is called after the user has |
| * been successfully authenticated. During this message exchange, pseudo |
| * terminals are allocated, X11, TCP/IP, and authentication agent forwardings |
| * are requested, etc. |
| */ |
| void |
| do_authenticated(struct passwd * pw) |
| { |
| Session *s; |
| int type; |
| int compression_level = 0, enable_compression_after_reply = 0; |
| int have_pty = 0; |
| char *command; |
| int n_bytes; |
| int plen; |
| unsigned int proto_len, data_len, dlen; |
| |
| /* |
| * Cancel the alarm we set to limit the time taken for |
| * authentication. |
| */ |
| alarm(0); |
| |
| /* |
| * Inform the channel mechanism that we are the server side and that |
| * the client may request to connect to any port at all. (The user |
| * could do it anyway, and we wouldn\'t know what is permitted except |
| * by the client telling us, so we can equally well trust the client |
| * not to request anything bogus.) |
| */ |
| if (!no_port_forwarding_flag) |
| channel_permit_all_opens(); |
| |
| s = session_new(); |
| |
| /* |
| * We stay in this loop until the client requests to execute a shell |
| * or a command. |
| */ |
| for (;;) { |
| int success = 0; |
| |
| /* Get a packet from the client. */ |
| type = packet_read(&plen); |
| |
| /* Process the packet. */ |
| switch (type) { |
| case SSH_CMSG_REQUEST_COMPRESSION: |
| packet_integrity_check(plen, 4, type); |
| compression_level = packet_get_int(); |
| if (compression_level < 1 || compression_level > 9) { |
| packet_send_debug("Received illegal compression level %d.", |
| compression_level); |
| break; |
| } |
| /* Enable compression after we have responded with SUCCESS. */ |
| enable_compression_after_reply = 1; |
| success = 1; |
| break; |
| |
| case SSH_CMSG_REQUEST_PTY: |
| if (no_pty_flag) { |
| debug("Allocating a pty not permitted for this authentication."); |
| break; |
| } |
| if (have_pty) |
| packet_disconnect("Protocol error: you already have a pty."); |
| |
| debug("Allocating pty."); |
| |
| /* Allocate a pty and open it. */ |
| if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, |
| sizeof(s->tty))) { |
| error("Failed to allocate pty."); |
| break; |
| } |
| fatal_add_cleanup(pty_cleanup_proc, (void *)s); |
| pty_setowner(pw, s->tty); |
| |
| /* Get TERM from the packet. Note that the value may be of arbitrary length. */ |
| s->term = packet_get_string(&dlen); |
| packet_integrity_check(dlen, strlen(s->term), type); |
| /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */ |
| /* Remaining bytes */ |
| n_bytes = plen - (4 + dlen + 4 * 4); |
| |
| if (strcmp(s->term, "") == 0) { |
| xfree(s->term); |
| s->term = NULL; |
| } |
| /* Get window size from the packet. */ |
| s->row = packet_get_int(); |
| s->col = packet_get_int(); |
| s->xpixel = packet_get_int(); |
| s->ypixel = packet_get_int(); |
| pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); |
| |
| /* Get tty modes from the packet. */ |
| tty_parse_modes(s->ttyfd, &n_bytes); |
| packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); |
| |
| /* Indicate that we now have a pty. */ |
| success = 1; |
| have_pty = 1; |
| break; |
| |
| case SSH_CMSG_X11_REQUEST_FORWARDING: |
| if (!options.x11_forwarding) { |
| packet_send_debug("X11 forwarding disabled in server configuration file."); |
| break; |
| } |
| #ifdef XAUTH_PATH |
| if (no_x11_forwarding_flag) { |
| packet_send_debug("X11 forwarding not permitted for this authentication."); |
| break; |
| } |
| debug("Received request for X11 forwarding with auth spoofing."); |
| if (s->display != NULL) |
| packet_disconnect("Protocol error: X11 display already set."); |
| |
| s->auth_proto = packet_get_string(&proto_len); |
| s->auth_data = packet_get_string(&data_len); |
| packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); |
| |
| if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) |
| s->screen = packet_get_int(); |
| else |
| s->screen = 0; |
| s->display = x11_create_display_inet(s->screen, options.x11_display_offset); |
| |
| if (s->display == NULL) |
| break; |
| |
| /* Setup to always have a local .Xauthority. */ |
| xauthfile = xmalloc(MAXPATHLEN); |
| strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); |
| temporarily_use_uid(pw->pw_uid); |
| if (mkdtemp(xauthfile) == NULL) { |
| restore_uid(); |
| error("private X11 dir: mkdtemp %s failed: %s", |
| xauthfile, strerror(errno)); |
| xfree(xauthfile); |
| xauthfile = NULL; |
| break; |
| } |
| strlcat(xauthfile, "/cookies", MAXPATHLEN); |
| open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600); |
| restore_uid(); |
| fatal_add_cleanup(xauthfile_cleanup_proc, NULL); |
| success = 1; |
| break; |
| #else /* XAUTH_PATH */ |
| packet_send_debug("No xauth program; cannot forward with spoofing."); |
| break; |
| #endif /* XAUTH_PATH */ |
| |
| case SSH_CMSG_AGENT_REQUEST_FORWARDING: |
| if (no_agent_forwarding_flag || compat13) { |
| debug("Authentication agent forwarding not permitted for this authentication."); |
| break; |
| } |
| debug("Received authentication agent forwarding request."); |
| auth_input_request_forwarding(pw); |
| success = 1; |
| break; |
| |
| case SSH_CMSG_PORT_FORWARD_REQUEST: |
| if (no_port_forwarding_flag) { |
| debug("Port forwarding not permitted for this authentication."); |
| break; |
| } |
| debug("Received TCP/IP port forwarding request."); |
| channel_input_port_forward_request(pw->pw_uid == 0); |
| success = 1; |
| break; |
| |
| case SSH_CMSG_MAX_PACKET_SIZE: |
| if (packet_set_maxsize(packet_get_int()) > 0) |
| success = 1; |
| break; |
| |
| case SSH_CMSG_EXEC_SHELL: |
| case SSH_CMSG_EXEC_CMD: |
| /* Set interactive/non-interactive mode. */ |
| packet_set_interactive(have_pty || s->display != NULL, |
| options.keepalives); |
| |
| if (type == SSH_CMSG_EXEC_CMD) { |
| command = packet_get_string(&dlen); |
| debug("Exec command '%.500s'", command); |
| packet_integrity_check(plen, 4 + dlen, type); |
| } else { |
| command = NULL; |
| packet_integrity_check(plen, 0, type); |
| } |
| if (forced_command != NULL) { |
| command = forced_command; |
| debug("Forced command '%.500s'", forced_command); |
| } |
| if (have_pty) |
| do_exec_pty(s, command, pw); |
| else |
| do_exec_no_pty(s, command, pw); |
| |
| if (command != NULL) |
| xfree(command); |
| /* Cleanup user's local Xauthority file. */ |
| if (xauthfile) |
| xauthfile_cleanup_proc(NULL); |
| return; |
| |
| default: |
| /* |
| * Any unknown messages in this phase are ignored, |
| * and a failure message is returned. |
| */ |
| log("Unknown packet type received after authentication: %d", type); |
| } |
| packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); |
| packet_send(); |
| packet_write_wait(); |
| |
| /* Enable compression now that we have replied if appropriate. */ |
| if (enable_compression_after_reply) { |
| enable_compression_after_reply = 0; |
| packet_start_compression(compression_level); |
| } |
| } |
| } |
| |
| /* |
| * This is called to fork and execute a command when we have no tty. This |
| * will call do_child from the child, and server_loop from the parent after |
| * setting up file descriptors and such. |
| */ |
| void |
| do_exec_no_pty(Session *s, const char *command, struct passwd * pw) |
| { |
| int pid; |
| |
| #ifdef USE_PIPES |
| int pin[2], pout[2], perr[2]; |
| /* Allocate pipes for communicating with the program. */ |
| if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) |
| packet_disconnect("Could not create pipes: %.100s", |
| strerror(errno)); |
| #else /* USE_PIPES */ |
| int inout[2], err[2]; |
| /* Uses socket pairs to communicate with the program. */ |
| if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || |
| socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) |
| packet_disconnect("Could not create socket pairs: %.100s", |
| strerror(errno)); |
| #endif /* USE_PIPES */ |
| if (s == NULL) |
| fatal("do_exec_no_pty: no session"); |
| |
| setproctitle("%s@notty", pw->pw_name); |
| |
| #ifdef USE_PAM |
| do_pam_setcred(); |
| #endif /* USE_PAM */ |
| |
| /* Fork the child. */ |
| if ((pid = fork()) == 0) { |
| /* Child. Reinitialize the log since the pid has changed. */ |
| log_init(__progname, options.log_level, options.log_facility, log_stderr); |
| |
| /* |
| * Create a new session and process group since the 4.4BSD |
| * setlogin() affects the entire process group. |
| */ |
| if (setsid() < 0) |
| error("setsid failed: %.100s", strerror(errno)); |
| |
| #ifdef USE_PIPES |
| /* |
| * Redirect stdin. We close the parent side of the socket |
| * pair, and make the child side the standard input. |
| */ |
| close(pin[1]); |
| if (dup2(pin[0], 0) < 0) |
| perror("dup2 stdin"); |
| close(pin[0]); |
| |
| /* Redirect stdout. */ |
| close(pout[0]); |
| if (dup2(pout[1], 1) < 0) |
| perror("dup2 stdout"); |
| close(pout[1]); |
| |
| /* Redirect stderr. */ |
| close(perr[0]); |
| if (dup2(perr[1], 2) < 0) |
| perror("dup2 stderr"); |
| close(perr[1]); |
| #else /* USE_PIPES */ |
| /* |
| * Redirect stdin, stdout, and stderr. Stdin and stdout will |
| * use the same socket, as some programs (particularly rdist) |
| * seem to depend on it. |
| */ |
| close(inout[1]); |
| close(err[1]); |
| if (dup2(inout[0], 0) < 0) /* stdin */ |
| perror("dup2 stdin"); |
| if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ |
| perror("dup2 stdout"); |
| if (dup2(err[0], 2) < 0) /* stderr */ |
| perror("dup2 stderr"); |
| #endif /* USE_PIPES */ |
| |
| /* Do processing for the child (exec command etc). */ |
| do_child(command, pw, NULL, s->display, s->auth_proto, s->auth_data, NULL); |
| /* NOTREACHED */ |
| } |
| if (pid < 0) |
| packet_disconnect("fork failed: %.100s", strerror(errno)); |
| s->pid = pid; |
| #ifdef USE_PIPES |
| /* We are the parent. Close the child sides of the pipes. */ |
| close(pin[0]); |
| close(pout[1]); |
| close(perr[1]); |
| |
| if (compat20) { |
| session_set_fds(s, pin[1], pout[0], perr[0]); |
| } else { |
| /* Enter the interactive session. */ |
| server_loop(pid, pin[1], pout[0], perr[0]); |
| /* server_loop has closed pin[1], pout[1], and perr[1]. */ |
| } |
| #else /* USE_PIPES */ |
| /* We are the parent. Close the child sides of the socket pairs. */ |
| close(inout[0]); |
| close(err[0]); |
| |
| /* |
| * Enter the interactive session. Note: server_loop must be able to |
| * handle the case that fdin and fdout are the same. |
| */ |
| if (compat20) { |
| session_set_fds(s, inout[1], inout[1], err[1]); |
| } else { |
| server_loop(pid, inout[1], inout[1], err[1]); |
| /* server_loop has closed inout[1] and err[1]. */ |
| } |
| #endif /* USE_PIPES */ |
| } |
| |
| /* |
| * This is called to fork and execute a command when we have a tty. This |
| * will call do_child from the child, and server_loop from the parent after |
| * setting up file descriptors, controlling tty, updating wtmp, utmp, |
| * lastlog, and other such operations. |
| */ |
| void |
| do_exec_pty(Session *s, const char *command, struct passwd * pw) |
| { |
| FILE *f; |
| char buf[100], *time_string; |
| char line[256]; |
| const char *hostname; |
| int fdout, ptyfd, ttyfd, ptymaster; |
| int quiet_login; |
| pid_t pid; |
| socklen_t fromlen; |
| struct sockaddr_storage from; |
| struct stat st; |
| time_t last_login_time; |
| |
| if (s == NULL) |
| fatal("do_exec_pty: no session"); |
| ptyfd = s->ptyfd; |
| ttyfd = s->ttyfd; |
| |
| /* Get remote host name. */ |
| hostname = get_canonical_hostname(); |
| |
| /* |
| * Get the time when the user last logged in. Buf will be set to |
| * contain the hostname the last login was from. |
| */ |
| if (!options.use_login) { |
| last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, |
| buf, sizeof(buf)); |
| } |
| setproctitle("%s@%s", pw->pw_name, strrchr(s->tty, '/') + 1); |
| |
| #ifdef USE_PAM |
| do_pam_session(pw->pw_name, s->tty); |
| do_pam_setcred(); |
| #endif /* USE_PAM */ |
| |
| /* Fork the child. */ |
| if ((pid = fork()) == 0) { |
| pid = getpid(); |
| |
| /* Child. Reinitialize the log because the pid has |
| changed. */ |
| log_init(__progname, options.log_level, options.log_facility, log_stderr); |
| |
| /* Close the master side of the pseudo tty. */ |
| close(ptyfd); |
| |
| /* Make the pseudo tty our controlling tty. */ |
| pty_make_controlling_tty(&ttyfd, s->tty); |
| |
| /* Redirect stdin from the pseudo tty. */ |
| if (dup2(ttyfd, fileno(stdin)) < 0) |
| error("dup2 stdin failed: %.100s", strerror(errno)); |
| |
| /* Redirect stdout to the pseudo tty. */ |
| if (dup2(ttyfd, fileno(stdout)) < 0) |
| error("dup2 stdin failed: %.100s", strerror(errno)); |
| |
| /* Redirect stderr to the pseudo tty. */ |
| if (dup2(ttyfd, fileno(stderr)) < 0) |
| error("dup2 stdin failed: %.100s", strerror(errno)); |
| |
| /* Close the extra descriptor for the pseudo tty. */ |
| close(ttyfd); |
| |
| ///XXXX ? move to do_child() ?? |
| /* |
| * Get IP address of client. This is needed because we want |
| * to record where the user logged in from. If the |
| * connection is not a socket, let the ip address be 0.0.0.0. |
| */ |
| memset(&from, 0, sizeof(from)); |
| if (packet_connection_is_on_socket()) { |
| fromlen = sizeof(from); |
| if (getpeername(packet_get_connection_in(), |
| (struct sockaddr *) & from, &fromlen) < 0) { |
| debug("getpeername: %.100s", strerror(errno)); |
| fatal_cleanup(); |
| } |
| } |
| /* Record that there was a login on that terminal. */ |
| record_login(pid, s->tty, pw->pw_name, pw->pw_uid, hostname, |
| (struct sockaddr *)&from); |
| |
| /* Check if .hushlogin exists. */ |
| snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); |
| quiet_login = stat(line, &st) >= 0; |
| |
| #ifdef USE_PAM |
| if (!quiet_login) |
| print_pam_messages(); |
| #endif /* USE_PAM */ |
| |
| /* |
| * If the user has logged in before, display the time of last |
| * login. However, don't display anything extra if a command |
| * has been specified (so that ssh can be used to execute |
| * commands on a remote machine without users knowing they |
| * are going to another machine). Login(1) will do this for |
| * us as well, so check if login(1) is used |
| */ |
| if (command == NULL && last_login_time != 0 && !quiet_login && |
| !options.use_login) { |
| /* Convert the date to a string. */ |
| time_string = ctime(&last_login_time); |
| /* Remove the trailing newline. */ |
| if (strchr(time_string, '\n')) |
| *strchr(time_string, '\n') = 0; |
| /* Display the last login time. Host if displayed |
| if known. */ |
| if (strcmp(buf, "") == 0) |
| printf("Last login: %s\r\n", time_string); |
| else |
| printf("Last login: %s from %s\r\n", time_string, buf); |
| } |
| /* |
| * Print /etc/motd unless a command was specified or printing |
| * it was disabled in server options or login(1) will be |
| * used. Note that some machines appear to print it in |
| * /etc/profile or similar. |
| */ |
| if (command == NULL && options.print_motd && !quiet_login && |
| !options.use_login) { |
| /* Print /etc/motd if it exists. */ |
| f = fopen("/etc/motd", "r"); |
| if (f) { |
| while (fgets(line, sizeof(line), f)) |
| fputs(line, stdout); |
| fclose(f); |
| } |
| } |
| /* Do common processing for the child, such as execing the command. */ |
| do_child(command, pw, s->term, s->display, s->auth_proto, s->auth_data, s->tty); |
| /* NOTREACHED */ |
| } |
| if (pid < 0) |
| packet_disconnect("fork failed: %.100s", strerror(errno)); |
| s->pid = pid; |
| |
| /* Parent. Close the slave side of the pseudo tty. */ |
| close(ttyfd); |
| |
| /* |
| * Create another descriptor of the pty master side for use as the |
| * standard input. We could use the original descriptor, but this |
| * simplifies code in server_loop. The descriptor is bidirectional. |
| */ |
| fdout = dup(ptyfd); |
| if (fdout < 0) |
| packet_disconnect("dup #1 failed: %.100s", strerror(errno)); |
| |
| /* we keep a reference to the pty master */ |
| ptymaster = dup(ptyfd); |
| if (ptymaster < 0) |
| packet_disconnect("dup #2 failed: %.100s", strerror(errno)); |
| s->ptymaster = ptymaster; |
| |
| /* Enter interactive session. */ |
| if (compat20) { |
| session_set_fds(s, ptyfd, fdout, -1); |
| } else { |
| server_loop(pid, ptyfd, fdout, -1); |
| /* server_loop _has_ closed ptyfd and fdout. */ |
| session_pty_cleanup(s); |
| } |
| } |
| |
| /* |
| * Sets the value of the given variable in the environment. If the variable |
| * already exists, its value is overriden. |
| */ |
| void |
| child_set_env(char ***envp, unsigned int *envsizep, const char *name, |
| const char *value) |
| { |
| unsigned int i, namelen; |
| char **env; |
| |
| /* |
| * Find the slot where the value should be stored. If the variable |
| * already exists, we reuse the slot; otherwise we append a new slot |
| * at the end of the array, expanding if necessary. |
| */ |
| env = *envp; |
| namelen = strlen(name); |
| for (i = 0; env[i]; i++) |
| if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') |
| break; |
| if (env[i]) { |
| /* Reuse the slot. */ |
| xfree(env[i]); |
| } else { |
| /* New variable. Expand if necessary. */ |
| if (i >= (*envsizep) - 1) { |
| (*envsizep) += 50; |
| env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); |
| } |
| /* Need to set the NULL pointer at end of array beyond the new slot. */ |
| env[i + 1] = NULL; |
| } |
| |
| /* Allocate space and format the variable in the appropriate slot. */ |
| env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); |
| snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); |
| } |
| |
| /* |
| * Reads environment variables from the given file and adds/overrides them |
| * into the environment. If the file does not exist, this does nothing. |
| * Otherwise, it must consist of empty lines, comments (line starts with '#') |
| * and assignments of the form name=value. No other forms are allowed. |
| */ |
| void |
| read_environment_file(char ***env, unsigned int *envsize, |
| const char *filename) |
| { |
| FILE *f; |
| char buf[4096]; |
| char *cp, *value; |
| |
| f = fopen(filename, "r"); |
| if (!f) |
| return; |
| |
| while (fgets(buf, sizeof(buf), f)) { |
| for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) |
| ; |
| if (!*cp || *cp == '#' || *cp == '\n') |
| continue; |
| if (strchr(cp, '\n')) |
| *strchr(cp, '\n') = '\0'; |
| value = strchr(cp, '='); |
| if (value == NULL) { |
| fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); |
| continue; |
| } |
| /* Replace the equals sign by nul, and advance value to the value string. */ |
| *value = '\0'; |
| value++; |
| child_set_env(env, envsize, cp, value); |
| } |
| fclose(f); |
| } |
| |
| #ifdef USE_PAM |
| /* |
| * Sets any environment variables which have been specified by PAM |
| */ |
| void do_pam_environment(char ***env, int *envsize) |
| { |
| char *equals, var_name[512], var_val[512]; |
| char **pam_env; |
| int i; |
| |
| if ((pam_env = fetch_pam_environment()) == NULL) |
| return; |
| |
| for(i = 0; pam_env[i] != NULL; i++) { |
| if ((equals = strstr(pam_env[i], "=")) == NULL) |
| continue; |
| |
| if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) { |
| memset(var_name, '\0', sizeof(var_name)); |
| memset(var_val, '\0', sizeof(var_val)); |
| |
| strncpy(var_name, pam_env[i], equals - pam_env[i]); |
| strcpy(var_val, equals + 1); |
| |
| debug("PAM environment: %s=%s", var_name, var_val); |
| |
| child_set_env(env, envsize, var_name, var_val); |
| } |
| } |
| } |
| #endif /* USE_PAM */ |
| |
| /* |
| * Performs common processing for the child, such as setting up the |
| * environment, closing extra file descriptors, setting the user and group |
| * ids, and executing the command or shell. |
| */ |
| void |
| do_child(const char *command, struct passwd * pw, const char *term, |
| const char *display, const char *auth_proto, |
| const char *auth_data, const char *ttyname) |
| { |
| const char *shell, *cp = NULL; |
| char buf[256]; |
| FILE *f; |
| unsigned int envsize, i; |
| char **env; |
| extern char **environ; |
| struct stat st; |
| char *argv[10]; |
| |
| #ifndef USE_PAM /* pam_nologin handles this */ |
| f = fopen("/etc/nologin", "r"); |
| if (f) { |
| /* /etc/nologin exists. Print its contents and exit. */ |
| while (fgets(buf, sizeof(buf), f)) |
| fputs(buf, stderr); |
| fclose(f); |
| if (pw->pw_uid != 0) |
| exit(254); |
| } |
| #endif /* USE_PAM */ |
| |
| /* Set login name in the kernel. */ |
| if (setlogin(pw->pw_name) < 0) |
| error("setlogin failed: %s", strerror(errno)); |
| |
| /* Set uid, gid, and groups. */ |
| /* Login(1) does this as well, and it needs uid 0 for the "-h" |
| switch, so we let login(1) to this for us. */ |
| if (!options.use_login) { |
| if (getuid() == 0 || geteuid() == 0) { |
| if (setgid(pw->pw_gid) < 0) { |
| perror("setgid"); |
| exit(1); |
| } |
| /* Initialize the group list. */ |
| if (initgroups(pw->pw_name, pw->pw_gid) < 0) { |
| perror("initgroups"); |
| exit(1); |
| } |
| endgrent(); |
| |
| /* Permanently switch to the desired uid. */ |
| permanently_set_uid(pw->pw_uid); |
| } |
| if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) |
| fatal("Failed to set uids to %d.", (int) pw->pw_uid); |
| } |
| /* |
| * Get the shell from the password data. An empty shell field is |
| * legal, and means /bin/sh. |
| */ |
| shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; |
| |
| #ifdef AFS |
| /* Try to get AFS tokens for the local cell. */ |
| if (k_hasafs()) { |
| char cell[64]; |
| |
| if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) |
| krb_afslog(cell, 0); |
| |
| krb_afslog(0, 0); |
| } |
| #endif /* AFS */ |
| |
| /* Initialize the environment. */ |
| envsize = 100; |
| env = xmalloc(envsize * sizeof(char *)); |
| env[0] = NULL; |
| |
| if (!options.use_login) { |
| /* Set basic environment. */ |
| child_set_env(&env, &envsize, "USER", pw->pw_name); |
| child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); |
| child_set_env(&env, &envsize, "HOME", pw->pw_dir); |
| child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); |
| |
| snprintf(buf, sizeof buf, "%.200s/%.50s", |
| _PATH_MAILDIR, pw->pw_name); |
| child_set_env(&env, &envsize, "MAIL", buf); |
| |
| /* Normal systems set SHELL by default. */ |
| child_set_env(&env, &envsize, "SHELL", shell); |
| } |
| if (getenv("TZ")) |
| child_set_env(&env, &envsize, "TZ", getenv("TZ")); |
| |
| /* Set custom environment options from RSA authentication. */ |
| while (custom_environment) { |
| struct envstring *ce = custom_environment; |
| char *s = ce->s; |
| int i; |
| for (i = 0; s[i] != '=' && s[i]; i++); |
| if (s[i] == '=') { |
| s[i] = 0; |
| child_set_env(&env, &envsize, s, s + i + 1); |
| } |
| custom_environment = ce->next; |
| xfree(ce->s); |
| xfree(ce); |
| } |
| |
| snprintf(buf, sizeof buf, "%.50s %d %d", |
| get_remote_ipaddr(), get_remote_port(), get_local_port()); |
| child_set_env(&env, &envsize, "SSH_CLIENT", buf); |
| |
| if (ttyname) |
| child_set_env(&env, &envsize, "SSH_TTY", ttyname); |
| if (term) |
| child_set_env(&env, &envsize, "TERM", term); |
| if (display) |
| child_set_env(&env, &envsize, "DISPLAY", display); |
| |
| #ifdef _AIX |
| { |
| char *authstate,*krb5cc; |
| |
| if ((authstate = getenv("AUTHSTATE")) != NULL) |
| child_set_env(&env,&envsize,"AUTHSTATE",authstate); |
| |
| if ((krb5cc = getenv("KRB5CCNAME")) != NULL) |
| child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc); |
| } |
| #endif |
| |
| #ifdef KRB4 |
| { |
| extern char *ticket; |
| |
| if (ticket) |
| child_set_env(&env, &envsize, "KRBTKFILE", ticket); |
| } |
| #endif /* KRB4 */ |
| |
| #ifdef USE_PAM |
| /* Pull in any environment variables that may have been set by PAM. */ |
| do_pam_environment(&env, &envsize); |
| #endif /* USE_PAM */ |
| |
| read_environment_file(&env,&envsize,"/etc/environment"); |
| |
| if (xauthfile) |
| child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); |
| if (auth_get_socket_name() != NULL) |
| child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, |
| auth_get_socket_name()); |
| |
| /* read $HOME/.ssh/environment. */ |
| if (!options.use_login) { |
| snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); |
| read_environment_file(&env, &envsize, buf); |
| } |
| if (debug_flag) { |
| /* dump the environment */ |
| fprintf(stderr, "Environment:\n"); |
| for (i = 0; env[i]; i++) |
| fprintf(stderr, " %.200s\n", env[i]); |
| } |
| /* |
| * Close the connection descriptors; note that this is the child, and |
| * the server will still have the socket open, and it is important |
| * that we do not shutdown it. Note that the descriptors cannot be |
| * closed before building the environment, as we call |
| * get_remote_ipaddr there. |
| */ |
| if (packet_get_connection_in() == packet_get_connection_out()) |
| close(packet_get_connection_in()); |
| else { |
| close(packet_get_connection_in()); |
| close(packet_get_connection_out()); |
| } |
| /* |
| * Close all descriptors related to channels. They will still remain |
| * open in the parent. |
| */ |
| /* XXX better use close-on-exec? -markus */ |
| channel_close_all(); |
| |
| /* |
| * Close any extra file descriptors. Note that there may still be |
| * descriptors left by system functions. They will be closed later. |
| */ |
| endpwent(); |
| |
| /* |
| * Close any extra open file descriptors so that we don\'t have them |
| * hanging around in clients. Note that we want to do this after |
| * initgroups, because at least on Solaris 2.3 it leaves file |
| * descriptors open. |
| */ |
| for (i = 3; i < 64; i++) |
| close(i); |
| |
| /* Change current directory to the user\'s home directory. */ |
| if (chdir(pw->pw_dir) < 0) |
| fprintf(stderr, "Could not chdir to home directory %s: %s\n", |
| pw->pw_dir, strerror(errno)); |
| |
| /* |
| * Must take new environment into use so that .ssh/rc, /etc/sshrc and |
| * xauth are run in the proper environment. |
| */ |
| environ = env; |
| |
| /* |
| * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first |
| * in this order). |
| */ |
| if (!options.use_login) { |
| if (stat(SSH_USER_RC, &st) >= 0) { |
| if (debug_flag) |
| fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); |
| |
| f = popen("/bin/sh " SSH_USER_RC, "w"); |
| if (f) { |
| if (auth_proto != NULL && auth_data != NULL) |
| fprintf(f, "%s %s\n", auth_proto, auth_data); |
| pclose(f); |
| } else |
| fprintf(stderr, "Could not run %s\n", SSH_USER_RC); |
| } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { |
| if (debug_flag) |
| fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); |
| |
| f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); |
| if (f) { |
| if (auth_proto != NULL && auth_data != NULL) |
| fprintf(f, "%s %s\n", auth_proto, auth_data); |
| pclose(f); |
| } else |
| fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); |
| } |
| #ifdef XAUTH_PATH |
| else { |
| /* Add authority data to .Xauthority if appropriate. */ |
| if (auth_proto != NULL && auth_data != NULL) { |
| if (debug_flag) |
| fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", |
| XAUTH_PATH, display, auth_proto, auth_data); |
| |
| f = popen(XAUTH_PATH " -q -", "w"); |
| if (f) { |
| fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); |
| pclose(f); |
| } else |
| fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); |
| } |
| } |
| #endif /* XAUTH_PATH */ |
| |
| /* Get the last component of the shell name. */ |
| cp = strrchr(shell, '/'); |
| if (cp) |
| cp++; |
| else |
| cp = shell; |
| } |
| /* |
| * If we have no command, execute the shell. In this case, the shell |
| * name to be passed in argv[0] is preceded by '-' to indicate that |
| * this is a login shell. |
| */ |
| if (!command) { |
| if (!options.use_login) { |
| char buf[256]; |
| |
| /* |
| * Check for mail if we have a tty and it was enabled |
| * in server options. |
| */ |
| if (ttyname && options.check_mail) { |
| char *mailbox; |
| struct stat mailstat; |
| mailbox = getenv("MAIL"); |
| if (mailbox != NULL) { |
| if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) |
| printf("No mail.\n"); |
| else if (mailstat.st_mtime < mailstat.st_atime) |
| printf("You have mail.\n"); |
| else |
| printf("You have new mail.\n"); |
| } |
| } |
| /* Start the shell. Set initial character to '-'. */ |
| buf[0] = '-'; |
| strncpy(buf + 1, cp, sizeof(buf) - 1); |
| buf[sizeof(buf) - 1] = 0; |
| |
| /* Execute the shell. */ |
| argv[0] = buf; |
| argv[1] = NULL; |
| execve(shell, argv, env); |
| |
| /* Executing the shell failed. */ |
| perror(shell); |
| exit(1); |
| |
| } else { |
| /* Launch login(1). */ |
| |
| execl("/usr/bin/login", "login", "-h", get_remote_ipaddr(), |
| "-p", "-f", "--", pw->pw_name, NULL); |
| |
| /* Login couldn't be executed, die. */ |
| |
| perror("login"); |
| exit(1); |
| } |
| } |
| /* |
| * Execute the command using the user's shell. This uses the -c |
| * option to execute the command. |
| */ |
| argv[0] = (char *) cp; |
| argv[1] = "-c"; |
| argv[2] = (char *) command; |
| argv[3] = NULL; |
| execve(shell, argv, env); |
| perror(shell); |
| exit(1); |
| } |
| |
| Session * |
| session_new(void) |
| { |
| int i; |
| static int did_init = 0; |
| if (!did_init) { |
| debug("session_new: init"); |
| for(i = 0; i < MAX_SESSIONS; i++) { |
| sessions[i].used = 0; |
| sessions[i].self = i; |
| } |
| did_init = 1; |
| } |
| for(i = 0; i < MAX_SESSIONS; i++) { |
| Session *s = &sessions[i]; |
| if (! s->used) { |
| s->pid = 0; |
| s->chanid = -1; |
| s->ptyfd = -1; |
| s->ttyfd = -1; |
| s->term = NULL; |
| s->pw = NULL; |
| s->display = NULL; |
| s->screen = 0; |
| s->auth_data = NULL; |
| s->auth_proto = NULL; |
| s->used = 1; |
| debug("session_new: session %d", i); |
| return s; |
| } |
| } |
| return NULL; |
| } |
| |
| void |
| session_dump(void) |
| { |
| int i; |
| for(i = 0; i < MAX_SESSIONS; i++) { |
| Session *s = &sessions[i]; |
| debug("dump: used %d session %d %p channel %d pid %d", |
| s->used, |
| s->self, |
| s, |
| s->chanid, |
| s->pid); |
| } |
| } |
| |
| int |
| session_open(int chanid) |
| { |
| Session *s = session_new(); |
| debug("session_open: channel %d", chanid); |
| if (s == NULL) { |
| error("no more sessions"); |
| return 0; |
| } |
| debug("session_open: session %d: link with channel %d", s->self, chanid); |
| s->chanid = chanid; |
| s->pw = auth_get_user(); |
| if (s->pw == NULL) |
| fatal("no user for session %i channel %d", |
| s->self, s->chanid); |
| return 1; |
| } |
| |
| Session * |
| session_by_channel(int id) |
| { |
| int i; |
| for(i = 0; i < MAX_SESSIONS; i++) { |
| Session *s = &sessions[i]; |
| if (s->used && s->chanid == id) { |
| debug("session_by_channel: session %d channel %d", i, id); |
| return s; |
| } |
| } |
| debug("session_by_channel: unknown channel %d", id); |
| session_dump(); |
| return NULL; |
| } |
| |
| Session * |
| session_by_pid(pid_t pid) |
| { |
| int i; |
| debug("session_by_pid: pid %d", pid); |
| for(i = 0; i < MAX_SESSIONS; i++) { |
| Session *s = &sessions[i]; |
| if (s->used && s->pid == pid) |
| return s; |
| } |
| error("session_by_pid: unknown pid %d", pid); |
| session_dump(); |
| return NULL; |
| } |
| |
| int |
| session_window_change_req(Session *s) |
| { |
| s->col = packet_get_int(); |
| s->row = packet_get_int(); |
| s->xpixel = packet_get_int(); |
| s->ypixel = packet_get_int(); |
| packet_done(); |
| pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); |
| return 1; |
| } |
| |
| int |
| session_pty_req(Session *s) |
| { |
| unsigned int len; |
| char *term_modes; /* encoded terminal modes */ |
| |
| if (s->ttyfd != -1) |
| return 0; |
| s->term = packet_get_string(&len); |
| s->col = packet_get_int(); |
| s->row = packet_get_int(); |
| s->xpixel = packet_get_int(); |
| s->ypixel = packet_get_int(); |
| term_modes = packet_get_string(&len); |
| packet_done(); |
| |
| if (strcmp(s->term, "") == 0) { |
| xfree(s->term); |
| s->term = NULL; |
| } |
| /* Allocate a pty and open it. */ |
| if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) { |
| xfree(s->term); |
| s->term = NULL; |
| s->ptyfd = -1; |
| s->ttyfd = -1; |
| error("session_pty_req: session %d alloc failed", s->self); |
| xfree(term_modes); |
| return 0; |
| } |
| debug("session_pty_req: session %d alloc %s", s->self, s->tty); |
| /* |
| * Add a cleanup function to clear the utmp entry and record logout |
| * time in case we call fatal() (e.g., the connection gets closed). |
| */ |
| fatal_add_cleanup(pty_cleanup_proc, (void *)s); |
| pty_setowner(s->pw, s->tty); |
| /* Get window size from the packet. */ |
| pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); |
| |
| /* XXX parse and set terminal modes */ |
| xfree(term_modes); |
| return 1; |
| } |
| |
| void |
| session_input_channel_req(int id, void *arg) |
| { |
| unsigned int len; |
| int reply; |
| int success = 0; |
| char *rtype; |
| Session *s; |
| Channel *c; |
| |
| rtype = packet_get_string(&len); |
| reply = packet_get_char(); |
| |
| s = session_by_channel(id); |
| if (s == NULL) |
| fatal("session_input_channel_req: channel %d: no session", id); |
| c = channel_lookup(id); |
| if (c == NULL) |
| fatal("session_input_channel_req: channel %d: bad channel", id); |
| |
| debug("session_input_channel_req: session %d channel %d request %s reply %d", |
| s->self, id, rtype, reply); |
| |
| /* |
| * a session is in LARVAL state until a shell |
| * or programm is executed |
| */ |
| if (c->type == SSH_CHANNEL_LARVAL) { |
| if (strcmp(rtype, "shell") == 0) { |
| if (s->ttyfd == -1) |
| do_exec_no_pty(s, NULL, s->pw); |
| else |
| do_exec_pty(s, NULL, s->pw); |
| success = 1; |
| } else if (strcmp(rtype, "exec") == 0) { |
| char *command = packet_get_string(&len); |
| packet_done(); |
| if (s->ttyfd == -1) |
| do_exec_no_pty(s, command, s->pw); |
| else |
| do_exec_pty(s, command, s->pw); |
| xfree(command); |
| success = 1; |
| } else if (strcmp(rtype, "pty-req") == 0) { |
| success = session_pty_req(s); |
| } |
| } |
| if (strcmp(rtype, "window-change") == 0) { |
| success = session_window_change_req(s); |
| } |
| |
| if (reply) { |
| packet_start(success ? |
| SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| } |
| xfree(rtype); |
| } |
| |
| void |
| session_set_fds(Session *s, int fdin, int fdout, int fderr) |
| { |
| if (!compat20) |
| fatal("session_set_fds: called for proto != 2.0"); |
| /* |
| * now that have a child and a pipe to the child, |
| * we can activate our channel and register the fd's |
| */ |
| if (s->chanid == -1) |
| fatal("no channel for session %d", s->self); |
| channel_set_fds(s->chanid, |
| fdout, fdin, fderr, |
| fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ); |
| } |
| |
| void |
| session_pty_cleanup(Session *s) |
| { |
| if (s == NULL || s->ttyfd == -1) |
| return; |
| |
| debug("session_pty_cleanup: session %i release %s", s->self, s->tty); |
| |
| /* Cancel the cleanup function. */ |
| fatal_remove_cleanup(pty_cleanup_proc, (void *)s); |
| |
| /* Record that the user has logged out. */ |
| record_logout(s->pid, s->tty); |
| |
| /* Release the pseudo-tty. */ |
| pty_release(s->tty); |
| |
| /* |
| * Close the server side of the socket pairs. We must do this after |
| * the pty cleanup, so that another process doesn't get this pty |
| * while we're still cleaning up. |
| */ |
| if (close(s->ptymaster) < 0) |
| error("close(s->ptymaster): %s", strerror(errno)); |
| } |
| |
| void |
| session_exit_message(Session *s, int status) |
| { |
| Channel *c; |
| if (s == NULL) |
| fatal("session_close: no session"); |
| c = channel_lookup(s->chanid); |
| if (c == NULL) |
| fatal("session_close: session %d: no channel %d", |
| s->self, s->chanid); |
| debug("session_exit_message: session %d channel %d pid %d", |
| s->self, s->chanid, s->pid); |
| |
| if (WIFEXITED(status)) { |
| channel_request_start(s->chanid, |
| "exit-status", 0); |
| packet_put_int(WEXITSTATUS(status)); |
| packet_send(); |
| } else if (WIFSIGNALED(status)) { |
| channel_request_start(s->chanid, |
| "exit-signal", 0); |
| packet_put_int(WTERMSIG(status)); |
| packet_put_char(WCOREDUMP(status)); |
| packet_put_cstring(""); |
| packet_put_cstring(""); |
| packet_send(); |
| } else { |
| /* Some weird exit cause. Just exit. */ |
| packet_disconnect("wait returned status %04x.", status); |
| } |
| |
| /* disconnect channel */ |
| debug("session_exit_message: release channel %d", s->chanid); |
| channel_cancel_cleanup(s->chanid); |
| /* |
| * emulate a write failure with 'chan_write_failed', nobody will be |
| * interested in data we write. |
| * Note that we must not call 'chan_read_failed', since there could |
| * be some more data waiting in the pipe. |
| */ |
| chan_write_failed(c); |
| s->chanid = -1; |
| } |
| |
| void |
| session_free(Session *s) |
| { |
| debug("session_free: session %d pid %d", s->self, s->pid); |
| if (s->term) |
| xfree(s->term); |
| if (s->display) |
| xfree(s->display); |
| if (s->auth_data) |
| xfree(s->auth_data); |
| if (s->auth_proto) |
| xfree(s->auth_proto); |
| s->used = 0; |
| } |
| |
| void |
| session_close(Session *s) |
| { |
| session_pty_cleanup(s); |
| session_free(s); |
| } |
| |
| void |
| session_close_by_pid(pid_t pid, int status) |
| { |
| Session *s = session_by_pid(pid); |
| if (s == NULL) { |
| debug("session_close_by_pid: no session for pid %d", s->pid); |
| return; |
| } |
| if (s->chanid != -1) |
| session_exit_message(s, status); |
| session_close(s); |
| } |
| |
| /* |
| * this is called when a channel dies before |
| * the session 'child' itself dies |
| */ |
| void |
| session_close_by_channel(int id, void *arg) |
| { |
| Session *s = session_by_channel(id); |
| if (s == NULL) { |
| debug("session_close_by_channel: no session for channel %d", id); |
| return; |
| } |
| /* disconnect channel */ |
| channel_cancel_cleanup(s->chanid); |
| s->chanid = -1; |
| |
| debug("session_close_by_channel: channel %d kill %d", id, s->pid); |
| if (s->pid == 0) { |
| /* close session immediately */ |
| session_close(s); |
| } else { |
| /* notify child, delay session cleanup */ |
| if (kill(s->pid, (s->ttyfd == -1) ? SIGTERM : SIGHUP) < 0) |
| error("session_close_by_channel: kill %d: %s", |
| s->pid, strerror(errno)); |
| } |
| } |
| |
| void |
| do_authenticated2(void) |
| { |
| /* |
| * Cancel the alarm we set to limit the time taken for |
| * authentication. |
| */ |
| alarm(0); |
| server_loop2(); |
| } |