-/*
- * Remove local Xauthority file.
- */
-static void
-xauthfile_cleanup_proc(void *ignore)
-{
- debug("xauthfile_cleanup_proc called");
-
- if (xauthfile != NULL) {
- unlink(xauthfile);
- xfree(xauthfile);
- xauthfile = NULL;
- }
-}
-
-/*
- * 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)
-{
- int type;
- int compression_level = 0, enable_compression_after_reply = 0;
- int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1;
- int row, col, xpixel, ypixel, screen;
- char ttyname[64];
- char *command, *term = NULL, *display = NULL, *proto = NULL,
- *data = NULL;
- struct group *grp;
- gid_t tty_gid;
- mode_t tty_mode;
- int n_bytes;
-
- /*
- * 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.)
- */
- channel_permit_all_opens();
-
- /*
- * We stay in this loop until the client requests to execute a shell
- * or a command.
- */
- while (1) {
- int plen, dlen;
-
- /* 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);
- goto fail;
- }
- /* Enable compression after we have responded with SUCCESS. */
- enable_compression_after_reply = 1;
- break;
-
- case SSH_CMSG_REQUEST_PTY:
- if (no_pty_flag) {
- debug("Allocating a pty not permitted for this authentication.");
- goto fail;
- }
- if (have_pty)
- packet_disconnect("Protocol error: you already have a pty.");
-
- debug("Allocating pty.");
-
- /* Allocate a pty and open it. */
- if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
- sizeof(ttyname))) {
- error("Failed to allocate pty.");
- goto fail;
- }
- /* Determine the group to make the owner of the tty. */
- grp = getgrnam("tty");
- if (grp) {
- tty_gid = grp->gr_gid;
- tty_mode = S_IRUSR | S_IWUSR | S_IWGRP;
- } else {
- tty_gid = pw->pw_gid;
- tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
- }
-
- /* Change ownership of the tty. */
- if (chown(ttyname, pw->pw_uid, tty_gid) < 0)
- fatal("chown(%.100s, %d, %d) failed: %.100s",
- ttyname, pw->pw_uid, tty_gid, strerror(errno));
- if (chmod(ttyname, tty_mode) < 0)
- fatal("chmod(%.100s, 0%o) failed: %.100s",
- ttyname, tty_mode, strerror(errno));
-
- /* Get TERM from the packet. Note that the value may be of arbitrary length. */
- term = packet_get_string(&dlen);
- packet_integrity_check(dlen, strlen(term), type);
- /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
- /* Remaining bytes */
- n_bytes = plen - (4 + dlen + 4 * 4);
-
- if (strcmp(term, "") == 0)
- term = NULL;
-
- /* Get window size from the packet. */
- row = packet_get_int();
- col = packet_get_int();
- xpixel = packet_get_int();
- ypixel = packet_get_int();
- pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
-
- /* Get tty modes from the packet. */
- tty_parse_modes(ttyfd, &n_bytes);
- packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
-
- /* Indicate that we now have a pty. */
- have_pty = 1;
- break;
-
- case SSH_CMSG_X11_REQUEST_FORWARDING:
- if (!options.x11_forwarding) {
- packet_send_debug("X11 forwarding disabled in server configuration file.");
- goto fail;
- }
-#ifdef XAUTH_PATH
- if (no_x11_forwarding_flag) {
- packet_send_debug("X11 forwarding not permitted for this authentication.");
- goto fail;
- }
- debug("Received request for X11 forwarding with auth spoofing.");
- if (display)
- packet_disconnect("Protocol error: X11 display already set.");
- {
- int proto_len, data_len;
- proto = packet_get_string(&proto_len);
- 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)
- screen = packet_get_int();
- else
- screen = 0;
- display = x11_create_display_inet(screen);
- if (!display)
- goto fail;
-
- /* Setup to always have a local .Xauthority. */
- xauthfile = xmalloc(MAXPATHLEN);
- snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX");
-
- if ((xauthfd = mkstemp(xauthfile)) != -1) {
- fchown(xauthfd, pw->pw_uid, pw->pw_gid);
- close(xauthfd);
- fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
- } else {
- xfree(xauthfile);
- xauthfile = NULL;
- }
- break;
-#else /* XAUTH_PATH */
- packet_send_debug("No xauth program; cannot forward with spoofing.");
- goto fail;
-#endif /* XAUTH_PATH */
-
- case SSH_CMSG_AGENT_REQUEST_FORWARDING:
- if (no_agent_forwarding_flag) {
- debug("Authentication agent forwarding not permitted for this authentication.");
- goto fail;
- }
- debug("Received authentication agent forwarding request.");
- auth_input_request_forwarding(pw);
- break;
-
- case SSH_CMSG_PORT_FORWARD_REQUEST:
- if (no_port_forwarding_flag) {
- debug("Port forwarding not permitted for this authentication.");
- goto fail;
- }
- debug("Received TCP/IP port forwarding request.");
- channel_input_port_forward_request(pw->pw_uid == 0);
- break;
-
- case SSH_CMSG_MAX_PACKET_SIZE:
- if (packet_set_maxsize(packet_get_int()) < 0)
- goto fail;
- break;
-
- case SSH_CMSG_EXEC_SHELL:
- /* Set interactive/non-interactive mode. */
- packet_set_interactive(have_pty || display != NULL,
- options.keepalives);
-
- if (forced_command != NULL)
- goto do_forced_command;
- debug("Forking shell.");
- packet_integrity_check(plen, 0, type);
- if (have_pty)
- do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
- else
- do_exec_no_pty(NULL, pw, display, proto, data);
- return;
-
- case SSH_CMSG_EXEC_CMD:
- /* Set interactive/non-interactive mode. */
- packet_set_interactive(have_pty || display != NULL,
- options.keepalives);
-
- if (forced_command != NULL)
- goto do_forced_command;
- /* Get command from the packet. */
- {
- int dlen;
- command = packet_get_string(&dlen);
- debug("Executing command '%.500s'", command);
- packet_integrity_check(plen, 4 + dlen, type);
- }
- if (have_pty)
- do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
- else
- do_exec_no_pty(command, pw, display, proto, data);
- xfree(command);
- 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);
- goto fail;
- }
-
- /* The request was successfully processed. */
- packet_start(SSH_SMSG_SUCCESS);
- 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);
- }
- continue;
-
-fail:
- /* The request failed. */
- packet_start(SSH_SMSG_FAILURE);
- packet_send();
- packet_write_wait();
- continue;
-
-do_forced_command:
- /*
- * There is a forced command specified for this login.
- * Execute it.
- */
- debug("Executing forced command: %.900s", forced_command);
- if (have_pty)
- do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
- else
- do_exec_no_pty(forced_command, pw, display, proto, data);
- return;
- }
-}
-
-/*
- * 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(const char *command, struct passwd * pw,
- const char *display, const char *auth_proto,
- const char *auth_data)
-{
- 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 */
-
- setproctitle("%s@notty", pw->pw_name);
-
- /* Fork the child. */
- if ((pid = fork()) == 0) {
- /* Child. Reinitialize the log since the pid has changed. */
- log_init(av0, 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, display, auth_proto, auth_data, NULL);
- /* NOTREACHED */
- }
- if (pid < 0)
- packet_disconnect("fork failed: %.100s", strerror(errno));
-#ifdef USE_PIPES
- /* We are the parent. Close the child sides of the pipes. */
- close(pin[0]);
- close(pout[1]);
- close(perr[1]);
-
- /* 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.
- */
- server_loop(pid, inout[1], inout[1], err[1]);
- /* server_loop has closed inout[1] and err[1]. */
-#endif /* USE_PIPES */
-}
-
-struct pty_cleanup_context {
- const char *ttyname;
- int pid;
-};
-
-/*
- * Function to perform cleanup if we get aborted abnormally (e.g., due to a
- * dropped connection).
- */
-void
-pty_cleanup_proc(void *context)
-{
- struct pty_cleanup_context *cu = context;
-
- debug("pty_cleanup_proc called");
-
- /* Record that the user has logged out. */
- record_logout(cu->pid, cu->ttyname);
-
- /* Release the pseudo-tty. */
- pty_release(cu->ttyname);
-}
-
-/*
- * 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(const char *command, int ptyfd, int ttyfd,
- const char *ttyname, struct passwd * pw, const char *term,
- const char *display, const char *auth_proto,
- const char *auth_data)