| /* |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| * Server main loop for handling the interactive session. |
| * |
| * As far as I am concerned, the code I have written for this software |
| * can be used freely for any purpose. Any derived versions of this |
| * software must be clearly marked as such, and if the derived work is |
| * incompatible with the protocol description in the RFC file, it must be |
| * called by a name other than "ssh" or "Secure Shell". |
| * |
| * SSH2 support by Markus Friedl. |
| * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "includes.h" |
| |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| |
| #include <signal.h> |
| #include <termios.h> |
| |
| #include "xmalloc.h" |
| #include "packet.h" |
| #include "buffer.h" |
| #include "log.h" |
| #include "servconf.h" |
| #include "canohost.h" |
| #include "sshpty.h" |
| #include "channels.h" |
| #include "compat.h" |
| #include "ssh1.h" |
| #include "ssh2.h" |
| #include "auth.h" |
| #include "session.h" |
| #include "dispatch.h" |
| #include "auth-options.h" |
| #include "serverloop.h" |
| #include "misc.h" |
| #include "kex.h" |
| |
| extern ServerOptions options; |
| |
| /* XXX */ |
| extern Kex *xxx_kex; |
| extern Authctxt *the_authctxt; |
| extern int use_privsep; |
| |
| static Buffer stdin_buffer; /* Buffer for stdin data. */ |
| static Buffer stdout_buffer; /* Buffer for stdout data. */ |
| static Buffer stderr_buffer; /* Buffer for stderr data. */ |
| static int fdin; /* Descriptor for stdin (for writing) */ |
| static int fdout; /* Descriptor for stdout (for reading); |
| May be same number as fdin. */ |
| static int fderr; /* Descriptor for stderr. May be -1. */ |
| static long stdin_bytes = 0; /* Number of bytes written to stdin. */ |
| static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */ |
| static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */ |
| static long fdout_bytes = 0; /* Number of stdout bytes read from program. */ |
| static int stdin_eof = 0; /* EOF message received from client. */ |
| static int fdout_eof = 0; /* EOF encountered reading from fdout. */ |
| static int fderr_eof = 0; /* EOF encountered readung from fderr. */ |
| static int fdin_is_tty = 0; /* fdin points to a tty. */ |
| static int connection_in; /* Connection to client (input). */ |
| static int connection_out; /* Connection to client (output). */ |
| static int connection_closed = 0; /* Connection to client closed. */ |
| static u_int buffer_high; /* "Soft" max buffer size. */ |
| static int client_alive_timeouts = 0; |
| |
| /* |
| * This SIGCHLD kludge is used to detect when the child exits. The server |
| * will exit after that, as soon as forwarded connections have terminated. |
| */ |
| |
| static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */ |
| |
| /* Cleanup on signals (!use_privsep case only) */ |
| static volatile sig_atomic_t received_sigterm = 0; |
| |
| /* prototypes */ |
| static void server_init_dispatch(void); |
| |
| /* |
| * we write to this pipe if a SIGCHLD is caught in order to avoid |
| * the race between select() and child_terminated |
| */ |
| static int notify_pipe[2]; |
| static void |
| notify_setup(void) |
| { |
| if (pipe(notify_pipe) < 0) { |
| error("pipe(notify_pipe) failed %s", strerror(errno)); |
| } else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) || |
| (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) { |
| error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno)); |
| close(notify_pipe[0]); |
| close(notify_pipe[1]); |
| } else { |
| set_nonblock(notify_pipe[0]); |
| set_nonblock(notify_pipe[1]); |
| return; |
| } |
| notify_pipe[0] = -1; /* read end */ |
| notify_pipe[1] = -1; /* write end */ |
| } |
| static void |
| notify_parent(void) |
| { |
| if (notify_pipe[1] != -1) |
| write(notify_pipe[1], "", 1); |
| } |
| static void |
| notify_prepare(fd_set *readset) |
| { |
| if (notify_pipe[0] != -1) |
| FD_SET(notify_pipe[0], readset); |
| } |
| static void |
| notify_done(fd_set *readset) |
| { |
| char c; |
| |
| if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset)) |
| while (read(notify_pipe[0], &c, 1) != -1) |
| debug2("notify_done: reading"); |
| } |
| |
| static void |
| sigchld_handler(int sig) |
| { |
| int save_errno = errno; |
| child_terminated = 1; |
| #ifndef _UNICOS |
| mysignal(SIGCHLD, sigchld_handler); |
| #endif |
| notify_parent(); |
| errno = save_errno; |
| } |
| |
| static void |
| sigterm_handler(int sig) |
| { |
| received_sigterm = sig; |
| } |
| |
| /* |
| * Make packets from buffered stderr data, and buffer it for sending |
| * to the client. |
| */ |
| static void |
| make_packets_from_stderr_data(void) |
| { |
| u_int len; |
| |
| /* Send buffered stderr data to the client. */ |
| while (buffer_len(&stderr_buffer) > 0 && |
| packet_not_very_much_data_to_write()) { |
| len = buffer_len(&stderr_buffer); |
| if (packet_is_interactive()) { |
| if (len > 512) |
| len = 512; |
| } else { |
| /* Keep the packets at reasonable size. */ |
| if (len > packet_get_maxsize()) |
| len = packet_get_maxsize(); |
| } |
| packet_start(SSH_SMSG_STDERR_DATA); |
| packet_put_string(buffer_ptr(&stderr_buffer), len); |
| packet_send(); |
| buffer_consume(&stderr_buffer, len); |
| stderr_bytes += len; |
| } |
| } |
| |
| /* |
| * Make packets from buffered stdout data, and buffer it for sending to the |
| * client. |
| */ |
| static void |
| make_packets_from_stdout_data(void) |
| { |
| u_int len; |
| |
| /* Send buffered stdout data to the client. */ |
| while (buffer_len(&stdout_buffer) > 0 && |
| packet_not_very_much_data_to_write()) { |
| len = buffer_len(&stdout_buffer); |
| if (packet_is_interactive()) { |
| if (len > 512) |
| len = 512; |
| } else { |
| /* Keep the packets at reasonable size. */ |
| if (len > packet_get_maxsize()) |
| len = packet_get_maxsize(); |
| } |
| packet_start(SSH_SMSG_STDOUT_DATA); |
| packet_put_string(buffer_ptr(&stdout_buffer), len); |
| packet_send(); |
| buffer_consume(&stdout_buffer, len); |
| stdout_bytes += len; |
| } |
| } |
| |
| static void |
| client_alive_check(void) |
| { |
| int channel_id; |
| |
| /* timeout, check to see how many we have had */ |
| if (++client_alive_timeouts > options.client_alive_count_max) |
| packet_disconnect("Timeout, your session not responding."); |
| |
| /* |
| * send a bogus global/channel request with "wantreply", |
| * we should get back a failure |
| */ |
| if ((channel_id = channel_find_open()) == -1) { |
| packet_start(SSH2_MSG_GLOBAL_REQUEST); |
| packet_put_cstring("keepalive@openssh.com"); |
| packet_put_char(1); /* boolean: want reply */ |
| } else { |
| channel_request_start(channel_id, "keepalive@openssh.com", 1); |
| } |
| packet_send(); |
| } |
| |
| /* |
| * Sleep in select() until we can do something. This will initialize the |
| * select masks. Upon return, the masks will indicate which descriptors |
| * have data or can accept data. Optionally, a maximum time can be specified |
| * for the duration of the wait (0 = infinite). |
| */ |
| static void |
| wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, |
| u_int *nallocp, u_int max_time_milliseconds) |
| { |
| struct timeval tv, *tvp; |
| int ret; |
| int client_alive_scheduled = 0; |
| |
| /* |
| * if using client_alive, set the max timeout accordingly, |
| * and indicate that this particular timeout was for client |
| * alive by setting the client_alive_scheduled flag. |
| * |
| * this could be randomized somewhat to make traffic |
| * analysis more difficult, but we're not doing it yet. |
| */ |
| if (compat20 && |
| max_time_milliseconds == 0 && options.client_alive_interval) { |
| client_alive_scheduled = 1; |
| max_time_milliseconds = options.client_alive_interval * 1000; |
| } |
| |
| /* Allocate and update select() masks for channel descriptors. */ |
| channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0); |
| |
| if (compat20) { |
| #if 0 |
| /* wrong: bad condition XXX */ |
| if (channel_not_very_much_buffered_data()) |
| #endif |
| FD_SET(connection_in, *readsetp); |
| } else { |
| /* |
| * Read packets from the client unless we have too much |
| * buffered stdin or channel data. |
| */ |
| if (buffer_len(&stdin_buffer) < buffer_high && |
| channel_not_very_much_buffered_data()) |
| FD_SET(connection_in, *readsetp); |
| /* |
| * If there is not too much data already buffered going to |
| * the client, try to get some more data from the program. |
| */ |
| if (packet_not_very_much_data_to_write()) { |
| if (!fdout_eof) |
| FD_SET(fdout, *readsetp); |
| if (!fderr_eof) |
| FD_SET(fderr, *readsetp); |
| } |
| /* |
| * If we have buffered data, try to write some of that data |
| * to the program. |
| */ |
| if (fdin != -1 && buffer_len(&stdin_buffer) > 0) |
| FD_SET(fdin, *writesetp); |
| } |
| notify_prepare(*readsetp); |
| |
| /* |
| * If we have buffered packet data going to the client, mark that |
| * descriptor. |
| */ |
| if (packet_have_data_to_write()) |
| FD_SET(connection_out, *writesetp); |
| |
| /* |
| * If child has terminated and there is enough buffer space to read |
| * from it, then read as much as is available and exit. |
| */ |
| if (child_terminated && packet_not_very_much_data_to_write()) |
| if (max_time_milliseconds == 0 || client_alive_scheduled) |
| max_time_milliseconds = 100; |
| |
| if (max_time_milliseconds == 0) |
| tvp = NULL; |
| else { |
| tv.tv_sec = max_time_milliseconds / 1000; |
| tv.tv_usec = 1000 * (max_time_milliseconds % 1000); |
| tvp = &tv; |
| } |
| |
| /* Wait for something to happen, or the timeout to expire. */ |
| ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); |
| |
| if (ret == -1) { |
| memset(*readsetp, 0, *nallocp); |
| memset(*writesetp, 0, *nallocp); |
| if (errno != EINTR) |
| error("select: %.100s", strerror(errno)); |
| } else if (ret == 0 && client_alive_scheduled) |
| client_alive_check(); |
| |
| notify_done(*readsetp); |
| } |
| |
| /* |
| * Processes input from the client and the program. Input data is stored |
| * in buffers and processed later. |
| */ |
| static void |
| process_input(fd_set * readset) |
| { |
| int len; |
| char buf[16384]; |
| |
| /* Read and buffer any input data from the client. */ |
| if (FD_ISSET(connection_in, readset)) { |
| len = read(connection_in, buf, sizeof(buf)); |
| if (len == 0) { |
| verbose("Connection closed by %.100s", |
| get_remote_ipaddr()); |
| connection_closed = 1; |
| if (compat20) |
| return; |
| cleanup_exit(255); |
| } else if (len < 0) { |
| if (errno != EINTR && errno != EAGAIN) { |
| verbose("Read error from remote host " |
| "%.100s: %.100s", |
| get_remote_ipaddr(), strerror(errno)); |
| cleanup_exit(255); |
| } |
| } else { |
| /* Buffer any received data. */ |
| packet_process_incoming(buf, len); |
| } |
| } |
| if (compat20) |
| return; |
| |
| /* Read and buffer any available stdout data from the program. */ |
| if (!fdout_eof && FD_ISSET(fdout, readset)) { |
| len = read(fdout, buf, sizeof(buf)); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
| /* do nothing */ |
| } else if (len <= 0) { |
| fdout_eof = 1; |
| } else { |
| buffer_append(&stdout_buffer, buf, len); |
| fdout_bytes += len; |
| } |
| } |
| /* Read and buffer any available stderr data from the program. */ |
| if (!fderr_eof && FD_ISSET(fderr, readset)) { |
| len = read(fderr, buf, sizeof(buf)); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
| /* do nothing */ |
| } else if (len <= 0) { |
| fderr_eof = 1; |
| } else { |
| buffer_append(&stderr_buffer, buf, len); |
| } |
| } |
| } |
| |
| /* |
| * Sends data from internal buffers to client program stdin. |
| */ |
| static void |
| process_output(fd_set * writeset) |
| { |
| struct termios tio; |
| u_char *data; |
| u_int dlen; |
| int len; |
| |
| /* Write buffered data to program stdin. */ |
| if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) { |
| data = buffer_ptr(&stdin_buffer); |
| dlen = buffer_len(&stdin_buffer); |
| len = write(fdin, data, dlen); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN)) { |
| /* do nothing */ |
| } else if (len <= 0) { |
| if (fdin != fdout) |
| close(fdin); |
| else |
| shutdown(fdin, SHUT_WR); /* We will no longer send. */ |
| fdin = -1; |
| } else { |
| /* Successful write. */ |
| if (fdin_is_tty && dlen >= 1 && data[0] != '\r' && |
| tcgetattr(fdin, &tio) == 0 && |
| !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { |
| /* |
| * Simulate echo to reduce the impact of |
| * traffic analysis |
| */ |
| packet_send_ignore(len); |
| packet_send(); |
| } |
| /* Consume the data from the buffer. */ |
| buffer_consume(&stdin_buffer, len); |
| /* Update the count of bytes written to the program. */ |
| stdin_bytes += len; |
| } |
| } |
| /* Send any buffered packet data to the client. */ |
| if (FD_ISSET(connection_out, writeset)) |
| packet_write_poll(); |
| } |
| |
| /* |
| * Wait until all buffered output has been sent to the client. |
| * This is used when the program terminates. |
| */ |
| static void |
| drain_output(void) |
| { |
| /* Send any buffered stdout data to the client. */ |
| if (buffer_len(&stdout_buffer) > 0) { |
| packet_start(SSH_SMSG_STDOUT_DATA); |
| packet_put_string(buffer_ptr(&stdout_buffer), |
| buffer_len(&stdout_buffer)); |
| packet_send(); |
| /* Update the count of sent bytes. */ |
| stdout_bytes += buffer_len(&stdout_buffer); |
| } |
| /* Send any buffered stderr data to the client. */ |
| if (buffer_len(&stderr_buffer) > 0) { |
| packet_start(SSH_SMSG_STDERR_DATA); |
| packet_put_string(buffer_ptr(&stderr_buffer), |
| buffer_len(&stderr_buffer)); |
| packet_send(); |
| /* Update the count of sent bytes. */ |
| stderr_bytes += buffer_len(&stderr_buffer); |
| } |
| /* Wait until all buffered data has been written to the client. */ |
| packet_write_wait(); |
| } |
| |
| static void |
| process_buffered_input_packets(void) |
| { |
| dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL); |
| } |
| |
| /* |
| * Performs the interactive session. This handles data transmission between |
| * the client and the program. Note that the notion of stdin, stdout, and |
| * stderr in this function is sort of reversed: this function writes to |
| * stdin (of the child program), and reads from stdout and stderr (of the |
| * child program). |
| */ |
| void |
| server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg) |
| { |
| fd_set *readset = NULL, *writeset = NULL; |
| int max_fd = 0; |
| u_int nalloc = 0; |
| int wait_status; /* Status returned by wait(). */ |
| pid_t wait_pid; /* pid returned by wait(). */ |
| int waiting_termination = 0; /* Have displayed waiting close message. */ |
| u_int max_time_milliseconds; |
| u_int previous_stdout_buffer_bytes; |
| u_int stdout_buffer_bytes; |
| int type; |
| |
| debug("Entering interactive session."); |
| |
| /* Initialize the SIGCHLD kludge. */ |
| child_terminated = 0; |
| mysignal(SIGCHLD, sigchld_handler); |
| |
| if (!use_privsep) { |
| signal(SIGTERM, sigterm_handler); |
| signal(SIGINT, sigterm_handler); |
| signal(SIGQUIT, sigterm_handler); |
| } |
| |
| /* Initialize our global variables. */ |
| fdin = fdin_arg; |
| fdout = fdout_arg; |
| fderr = fderr_arg; |
| |
| /* nonblocking IO */ |
| set_nonblock(fdin); |
| set_nonblock(fdout); |
| /* we don't have stderr for interactive terminal sessions, see below */ |
| if (fderr != -1) |
| set_nonblock(fderr); |
| |
| if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin)) |
| fdin_is_tty = 1; |
| |
| connection_in = packet_get_connection_in(); |
| connection_out = packet_get_connection_out(); |
| |
| notify_setup(); |
| |
| previous_stdout_buffer_bytes = 0; |
| |
| /* Set approximate I/O buffer size. */ |
| if (packet_is_interactive()) |
| buffer_high = 4096; |
| else |
| buffer_high = 64 * 1024; |
| |
| #if 0 |
| /* Initialize max_fd to the maximum of the known file descriptors. */ |
| max_fd = MAX(connection_in, connection_out); |
| max_fd = MAX(max_fd, fdin); |
| max_fd = MAX(max_fd, fdout); |
| if (fderr != -1) |
| max_fd = MAX(max_fd, fderr); |
| #endif |
| |
| /* Initialize Initialize buffers. */ |
| buffer_init(&stdin_buffer); |
| buffer_init(&stdout_buffer); |
| buffer_init(&stderr_buffer); |
| |
| /* |
| * If we have no separate fderr (which is the case when we have a pty |
| * - there we cannot make difference between data sent to stdout and |
| * stderr), indicate that we have seen an EOF from stderr. This way |
| * we don't need to check the descriptor everywhere. |
| */ |
| if (fderr == -1) |
| fderr_eof = 1; |
| |
| server_init_dispatch(); |
| |
| /* Main loop of the server for the interactive session mode. */ |
| for (;;) { |
| |
| /* Process buffered packets from the client. */ |
| process_buffered_input_packets(); |
| |
| /* |
| * If we have received eof, and there is no more pending |
| * input data, cause a real eof by closing fdin. |
| */ |
| if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) { |
| if (fdin != fdout) |
| close(fdin); |
| else |
| shutdown(fdin, SHUT_WR); /* We will no longer send. */ |
| fdin = -1; |
| } |
| /* Make packets from buffered stderr data to send to the client. */ |
| make_packets_from_stderr_data(); |
| |
| /* |
| * Make packets from buffered stdout data to send to the |
| * client. If there is very little to send, this arranges to |
| * not send them now, but to wait a short while to see if we |
| * are getting more data. This is necessary, as some systems |
| * wake up readers from a pty after each separate character. |
| */ |
| max_time_milliseconds = 0; |
| stdout_buffer_bytes = buffer_len(&stdout_buffer); |
| if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 && |
| stdout_buffer_bytes != previous_stdout_buffer_bytes) { |
| /* try again after a while */ |
| max_time_milliseconds = 10; |
| } else { |
| /* Send it now. */ |
| make_packets_from_stdout_data(); |
| } |
| previous_stdout_buffer_bytes = buffer_len(&stdout_buffer); |
| |
| /* Send channel data to the client. */ |
| if (packet_not_very_much_data_to_write()) |
| channel_output_poll(); |
| |
| /* |
| * Bail out of the loop if the program has closed its output |
| * descriptors, and we have no more data to send to the |
| * client, and there is no pending buffered data. |
| */ |
| if (fdout_eof && fderr_eof && !packet_have_data_to_write() && |
| buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) { |
| if (!channel_still_open()) |
| break; |
| if (!waiting_termination) { |
| const char *s = "Waiting for forwarded connections to terminate...\r\n"; |
| char *cp; |
| waiting_termination = 1; |
| buffer_append(&stderr_buffer, s, strlen(s)); |
| |
| /* Display list of open channels. */ |
| cp = channel_open_message(); |
| buffer_append(&stderr_buffer, cp, strlen(cp)); |
| xfree(cp); |
| } |
| } |
| max_fd = MAX(connection_in, connection_out); |
| max_fd = MAX(max_fd, fdin); |
| max_fd = MAX(max_fd, fdout); |
| max_fd = MAX(max_fd, fderr); |
| max_fd = MAX(max_fd, notify_pipe[0]); |
| |
| /* Sleep in select() until we can do something. */ |
| wait_until_can_do_something(&readset, &writeset, &max_fd, |
| &nalloc, max_time_milliseconds); |
| |
| if (received_sigterm) { |
| logit("Exiting on signal %d", received_sigterm); |
| /* Clean up sessions, utmp, etc. */ |
| cleanup_exit(255); |
| } |
| |
| /* Process any channel events. */ |
| channel_after_select(readset, writeset); |
| |
| /* Process input from the client and from program stdout/stderr. */ |
| process_input(readset); |
| |
| /* Process output to the client and to program stdin. */ |
| process_output(writeset); |
| } |
| if (readset) |
| xfree(readset); |
| if (writeset) |
| xfree(writeset); |
| |
| /* Cleanup and termination code. */ |
| |
| /* Wait until all output has been sent to the client. */ |
| drain_output(); |
| |
| debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.", |
| stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes); |
| |
| /* Free and clear the buffers. */ |
| buffer_free(&stdin_buffer); |
| buffer_free(&stdout_buffer); |
| buffer_free(&stderr_buffer); |
| |
| /* Close the file descriptors. */ |
| if (fdout != -1) |
| close(fdout); |
| fdout = -1; |
| fdout_eof = 1; |
| if (fderr != -1) |
| close(fderr); |
| fderr = -1; |
| fderr_eof = 1; |
| if (fdin != -1) |
| close(fdin); |
| fdin = -1; |
| |
| channel_free_all(); |
| |
| /* We no longer want our SIGCHLD handler to be called. */ |
| mysignal(SIGCHLD, SIG_DFL); |
| |
| while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0) |
| if (errno != EINTR) |
| packet_disconnect("wait: %.100s", strerror(errno)); |
| if (wait_pid != pid) |
| error("Strange, wait returned pid %ld, expected %ld", |
| (long)wait_pid, (long)pid); |
| |
| /* Check if it exited normally. */ |
| if (WIFEXITED(wait_status)) { |
| /* Yes, normal exit. Get exit status and send it to the client. */ |
| debug("Command exited with status %d.", WEXITSTATUS(wait_status)); |
| packet_start(SSH_SMSG_EXITSTATUS); |
| packet_put_int(WEXITSTATUS(wait_status)); |
| packet_send(); |
| packet_write_wait(); |
| |
| /* |
| * Wait for exit confirmation. Note that there might be |
| * other packets coming before it; however, the program has |
| * already died so we just ignore them. The client is |
| * supposed to respond with the confirmation when it receives |
| * the exit status. |
| */ |
| do { |
| type = packet_read(); |
| } |
| while (type != SSH_CMSG_EXIT_CONFIRMATION); |
| |
| debug("Received exit confirmation."); |
| return; |
| } |
| /* Check if the program terminated due to a signal. */ |
| if (WIFSIGNALED(wait_status)) |
| packet_disconnect("Command terminated on signal %d.", |
| WTERMSIG(wait_status)); |
| |
| /* Some weird exit cause. Just exit. */ |
| packet_disconnect("wait returned status %04x.", wait_status); |
| /* NOTREACHED */ |
| } |
| |
| static void |
| collect_children(void) |
| { |
| pid_t pid; |
| sigset_t oset, nset; |
| int status; |
| |
| /* block SIGCHLD while we check for dead children */ |
| sigemptyset(&nset); |
| sigaddset(&nset, SIGCHLD); |
| sigprocmask(SIG_BLOCK, &nset, &oset); |
| if (child_terminated) { |
| debug("Received SIGCHLD."); |
| while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
| (pid < 0 && errno == EINTR)) |
| if (pid > 0) |
| session_close_by_pid(pid, status); |
| child_terminated = 0; |
| } |
| sigprocmask(SIG_SETMASK, &oset, NULL); |
| } |
| |
| void |
| server_loop2(Authctxt *authctxt) |
| { |
| fd_set *readset = NULL, *writeset = NULL; |
| int rekeying = 0, max_fd, nalloc = 0; |
| |
| debug("Entering interactive session for SSH2."); |
| |
| mysignal(SIGCHLD, sigchld_handler); |
| child_terminated = 0; |
| connection_in = packet_get_connection_in(); |
| connection_out = packet_get_connection_out(); |
| |
| if (!use_privsep) { |
| signal(SIGTERM, sigterm_handler); |
| signal(SIGINT, sigterm_handler); |
| signal(SIGQUIT, sigterm_handler); |
| } |
| |
| notify_setup(); |
| |
| max_fd = MAX(connection_in, connection_out); |
| max_fd = MAX(max_fd, notify_pipe[0]); |
| |
| server_init_dispatch(); |
| |
| for (;;) { |
| process_buffered_input_packets(); |
| |
| rekeying = (xxx_kex != NULL && !xxx_kex->done); |
| |
| if (!rekeying && packet_not_very_much_data_to_write()) |
| channel_output_poll(); |
| wait_until_can_do_something(&readset, &writeset, &max_fd, |
| &nalloc, 0); |
| |
| if (received_sigterm) { |
| logit("Exiting on signal %d", received_sigterm); |
| /* Clean up sessions, utmp, etc. */ |
| cleanup_exit(255); |
| } |
| |
| collect_children(); |
| if (!rekeying) { |
| channel_after_select(readset, writeset); |
| if (packet_need_rekeying()) { |
| debug("need rekeying"); |
| xxx_kex->done = 0; |
| kex_send_kexinit(xxx_kex); |
| } |
| } |
| process_input(readset); |
| if (connection_closed) |
| break; |
| process_output(writeset); |
| } |
| collect_children(); |
| |
| if (readset) |
| xfree(readset); |
| if (writeset) |
| xfree(writeset); |
| |
| /* free all channels, no more reads and writes */ |
| channel_free_all(); |
| |
| /* free remaining sessions, e.g. remove wtmp entries */ |
| session_destroy_all(NULL); |
| } |
| |
| static void |
| server_input_keep_alive(int type, u_int32_t seq, void *ctxt) |
| { |
| debug("Got %d/%u for keepalive", type, seq); |
| /* |
| * reset timeout, since we got a sane answer from the client. |
| * even if this was generated by something other than |
| * the bogus CHANNEL_REQUEST we send for keepalives. |
| */ |
| client_alive_timeouts = 0; |
| } |
| |
| static void |
| server_input_stdin_data(int type, u_int32_t seq, void *ctxt) |
| { |
| char *data; |
| u_int data_len; |
| |
| /* Stdin data from the client. Append it to the buffer. */ |
| /* Ignore any data if the client has closed stdin. */ |
| if (fdin == -1) |
| return; |
| data = packet_get_string(&data_len); |
| packet_check_eom(); |
| buffer_append(&stdin_buffer, data, data_len); |
| memset(data, 0, data_len); |
| xfree(data); |
| } |
| |
| static void |
| server_input_eof(int type, u_int32_t seq, void *ctxt) |
| { |
| /* |
| * Eof from the client. The stdin descriptor to the |
| * program will be closed when all buffered data has |
| * drained. |
| */ |
| debug("EOF received for stdin."); |
| packet_check_eom(); |
| stdin_eof = 1; |
| } |
| |
| static void |
| server_input_window_size(int type, u_int32_t seq, void *ctxt) |
| { |
| int row = packet_get_int(); |
| int col = packet_get_int(); |
| int xpixel = packet_get_int(); |
| int ypixel = packet_get_int(); |
| |
| debug("Window change received."); |
| packet_check_eom(); |
| if (fdin != -1) |
| pty_change_window_size(fdin, row, col, xpixel, ypixel); |
| } |
| |
| static Channel * |
| server_request_direct_tcpip(void) |
| { |
| Channel *c; |
| int sock; |
| char *target, *originator; |
| int target_port, originator_port; |
| |
| target = packet_get_string(NULL); |
| target_port = packet_get_int(); |
| originator = packet_get_string(NULL); |
| originator_port = packet_get_int(); |
| packet_check_eom(); |
| |
| debug("server_request_direct_tcpip: originator %s port %d, target %s port %d", |
| originator, originator_port, target, target_port); |
| |
| /* XXX check permission */ |
| sock = channel_connect_to(target, target_port); |
| xfree(target); |
| xfree(originator); |
| if (sock < 0) |
| return NULL; |
| c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING, |
| sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, |
| CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1); |
| return c; |
| } |
| |
| static Channel * |
| server_request_tun(void) |
| { |
| Channel *c = NULL; |
| int mode, tun; |
| int sock; |
| |
| mode = packet_get_int(); |
| switch (mode) { |
| case SSH_TUNMODE_POINTOPOINT: |
| case SSH_TUNMODE_ETHERNET: |
| break; |
| default: |
| packet_send_debug("Unsupported tunnel device mode."); |
| return NULL; |
| } |
| if ((options.permit_tun & mode) == 0) { |
| packet_send_debug("Server has rejected tunnel device " |
| "forwarding"); |
| return NULL; |
| } |
| |
| tun = packet_get_int(); |
| if (forced_tun_device != -1) { |
| if (tun != SSH_TUNID_ANY && forced_tun_device != tun) |
| goto done; |
| tun = forced_tun_device; |
| } |
| sock = tun_open(tun, mode); |
| if (sock < 0) |
| goto done; |
| c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); |
| c->datagram = 1; |
| #if defined(SSH_TUN_FILTER) |
| if (mode == SSH_TUNMODE_POINTOPOINT) |
| channel_register_filter(c->self, sys_tun_infilter, |
| sys_tun_outfilter); |
| #endif |
| |
| done: |
| if (c == NULL) |
| packet_send_debug("Failed to open the tunnel device."); |
| return c; |
| } |
| |
| static Channel * |
| server_request_session(void) |
| { |
| Channel *c; |
| |
| debug("input_session_request"); |
| packet_check_eom(); |
| /* |
| * A server session has no fd to read or write until a |
| * CHANNEL_REQUEST for a shell is made, so we set the type to |
| * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all |
| * CHANNEL_REQUEST messages is registered. |
| */ |
| c = channel_new("session", SSH_CHANNEL_LARVAL, |
| -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT, |
| 0, "server-session", 1); |
| if (session_open(the_authctxt, c->self) != 1) { |
| debug("session open failed, free channel %d", c->self); |
| channel_free(c); |
| return NULL; |
| } |
| channel_register_cleanup(c->self, session_close_by_channel, 0); |
| return c; |
| } |
| |
| static void |
| server_input_channel_open(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c = NULL; |
| char *ctype; |
| int rchan; |
| u_int rmaxpack, rwindow, len; |
| |
| ctype = packet_get_string(&len); |
| rchan = packet_get_int(); |
| rwindow = packet_get_int(); |
| rmaxpack = packet_get_int(); |
| |
| debug("server_input_channel_open: ctype %s rchan %d win %d max %d", |
| ctype, rchan, rwindow, rmaxpack); |
| |
| if (strcmp(ctype, "session") == 0) { |
| c = server_request_session(); |
| } else if (strcmp(ctype, "direct-tcpip") == 0) { |
| c = server_request_direct_tcpip(); |
| } else if (strcmp(ctype, "tun@openssh.com") == 0) { |
| c = server_request_tun(); |
| } |
| if (c != NULL) { |
| debug("server_input_channel_open: confirm %s", ctype); |
| c->remote_id = rchan; |
| c->remote_window = rwindow; |
| c->remote_maxpacket = rmaxpack; |
| if (c->type != SSH_CHANNEL_CONNECTING) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); |
| packet_put_int(c->remote_id); |
| packet_put_int(c->self); |
| packet_put_int(c->local_window); |
| packet_put_int(c->local_maxpacket); |
| packet_send(); |
| } |
| } else { |
| debug("server_input_channel_open: failure %s", ctype); |
| packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(rchan); |
| packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); |
| if (!(datafellows & SSH_BUG_OPENFAILURE)) { |
| packet_put_cstring("open failed"); |
| packet_put_cstring(""); |
| } |
| packet_send(); |
| } |
| xfree(ctype); |
| } |
| |
| static void |
| server_input_global_request(int type, u_int32_t seq, void *ctxt) |
| { |
| char *rtype; |
| int want_reply; |
| int success = 0; |
| |
| rtype = packet_get_string(NULL); |
| want_reply = packet_get_char(); |
| debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply); |
| |
| /* -R style forwarding */ |
| if (strcmp(rtype, "tcpip-forward") == 0) { |
| struct passwd *pw; |
| char *listen_address; |
| u_short listen_port; |
| |
| pw = the_authctxt->pw; |
| if (pw == NULL || !the_authctxt->valid) |
| fatal("server_input_global_request: no/invalid user"); |
| listen_address = packet_get_string(NULL); |
| listen_port = (u_short)packet_get_int(); |
| debug("server_input_global_request: tcpip-forward listen %s port %d", |
| listen_address, listen_port); |
| |
| /* check permissions */ |
| if (!options.allow_tcp_forwarding || |
| no_port_forwarding_flag |
| #ifndef NO_IPPORT_RESERVED_CONCEPT |
| || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0) |
| #endif |
| ) { |
| success = 0; |
| packet_send_debug("Server has disabled port forwarding."); |
| } else { |
| /* Start listening on the port */ |
| success = channel_setup_remote_fwd_listener( |
| listen_address, listen_port, options.gateway_ports); |
| } |
| xfree(listen_address); |
| } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) { |
| char *cancel_address; |
| u_short cancel_port; |
| |
| cancel_address = packet_get_string(NULL); |
| cancel_port = (u_short)packet_get_int(); |
| debug("%s: cancel-tcpip-forward addr %s port %d", __func__, |
| cancel_address, cancel_port); |
| |
| success = channel_cancel_rport_listener(cancel_address, |
| cancel_port); |
| } |
| if (want_reply) { |
| packet_start(success ? |
| SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); |
| packet_send(); |
| packet_write_wait(); |
| } |
| xfree(rtype); |
| } |
| static void |
| server_input_channel_req(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c; |
| int id, reply, success = 0; |
| char *rtype; |
| |
| id = packet_get_int(); |
| rtype = packet_get_string(NULL); |
| reply = packet_get_char(); |
| |
| debug("server_input_channel_req: channel %d request %s reply %d", |
| id, rtype, reply); |
| |
| if ((c = channel_lookup(id)) == NULL) |
| packet_disconnect("server_input_channel_req: " |
| "unknown channel %d", id); |
| if (c->type == SSH_CHANNEL_LARVAL || c->type == SSH_CHANNEL_OPEN) |
| success = session_input_channel_req(c, rtype); |
| if (reply) { |
| packet_start(success ? |
| SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| } |
| xfree(rtype); |
| } |
| |
| static void |
| server_init_dispatch_20(void) |
| { |
| debug("server_init_dispatch_20"); |
| dispatch_init(&dispatch_protocol_error); |
| dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); |
| dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); |
| dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); |
| dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); |
| dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open); |
| dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); |
| dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); |
| dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req); |
| dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); |
| dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request); |
| /* client_alive */ |
| dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive); |
| dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive); |
| dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive); |
| /* rekeying */ |
| dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
| } |
| static void |
| server_init_dispatch_13(void) |
| { |
| debug("server_init_dispatch_13"); |
| dispatch_init(NULL); |
| dispatch_set(SSH_CMSG_EOF, &server_input_eof); |
| dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data); |
| dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size); |
| dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); |
| dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); |
| dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); |
| dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); |
| dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); |
| dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); |
| } |
| static void |
| server_init_dispatch_15(void) |
| { |
| server_init_dispatch_13(); |
| debug("server_init_dispatch_15"); |
| dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); |
| dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose); |
| } |
| static void |
| server_init_dispatch(void) |
| { |
| if (compat20) |
| server_init_dispatch_20(); |
| else if (compat13) |
| server_init_dispatch_13(); |
| else |
| server_init_dispatch_15(); |
| } |