diff options
Diffstat (limited to 'crypto/openssh/serverloop.c')
| -rw-r--r-- | crypto/openssh/serverloop.c | 1219 |
1 files changed, 0 insertions, 1219 deletions
diff --git a/crypto/openssh/serverloop.c b/crypto/openssh/serverloop.c deleted file mode 100644 index 69304b5..0000000 --- a/crypto/openssh/serverloop.c +++ /dev/null @@ -1,1219 +0,0 @@ -/* $OpenBSD: serverloop.c,v 1.145 2006/10/11 12:38:03 markus Exp $ */ -/* - * 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/param.h> -#include <sys/wait.h> -#include <sys/socket.h> -#ifdef HAVE_SYS_TIME_H -# include <sys/time.h> -#endif - -#include <netinet/in.h> - -#include <errno.h> -#include <fcntl.h> -#include <pwd.h> -#include <signal.h> -#include <string.h> -#include <termios.h> -#include <unistd.h> -#include <stdarg.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 "key.h" -#include "cipher.h" -#include "kex.h" -#include "hostfile.h" -#include "auth.h" -#include "session.h" -#include "dispatch.h" -#include "auth-options.h" -#include "serverloop.h" -#include "misc.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"); -} - -/*ARGSUSED*/ -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; -} - -/*ARGSUSED*/ -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) { - logit("Timeout, client not responding."); - cleanup_exit(255); - } - - /* - * 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)) { - errno = 0; - len = read(fdout, buf, sizeof(buf)); - if (len < 0 && (errno == EINTR || errno == EAGAIN)) { - /* do nothing */ -#ifndef PTY_ZEROREAD - } else if (len <= 0) { -#else - } else if ((!isatty(fdout) && len <= 0) || - (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) { -#endif - 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)) { - errno = 0; - len = read(fderr, buf, sizeof(buf)); - if (len < 0 && (errno == EINTR || errno == EAGAIN)) { - /* do nothing */ -#ifndef PTY_ZEROREAD - } else if (len <= 0) { -#else - } else if ((!isatty(fderr) && len <= 0) || - (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) { -#endif - 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) -{ - u_int row = packet_get_int(); - u_int col = packet_get_int(); - u_int xpixel = packet_get_int(); - u_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); - xfree(cancel_address); - } - 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(); -} |
