int
get_snd_buf_size(struct ssh *ssh)
{
int fd = ssh_packet_get_connection_out(ssh);
int optval;
socklen_t optvallen = sizeof(optval);
if (getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &optval, &optvallen) != 0)
optval = DEFAULT_ROAMBUF;
return optval;
}
void
server_loop2(struct ssh *ssh)
{
fd_set *readset = NULL, *writeset = NULL;
int r, rekeying = 0, max_fd;
u_int nalloc = 0;
u_int64_t rekey_timeout_ms = 0;
debug("Entering interactive session for SSH2.");
signal(SIGCHLD, sigchld_handler);
child_terminated = 0;
connection_in = ssh_packet_get_connection_in(ssh);
connection_out = ssh_packet_get_connection_out(ssh);
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(ssh);
for (;;) {
process_buffered_input_packets(ssh);
rekeying = (ssh->kex != NULL && !ssh->kex->done);
if (!rekeying && ssh_packet_not_very_much_data_to_write(ssh))
channel_output_poll();
if (options.rekey_interval > 0 && compat20 && !rekeying)
rekey_timeout_ms =
ssh_packet_get_rekey_timeout(ssh) * 1000;
else
rekey_timeout_ms = 0;
wait_until_can_do_something(ssh, &readset, &writeset, &max_fd,
&nalloc, rekey_timeout_ms);
if (received_sigterm) {
logit("Exiting on signal %d", (int)received_sigterm);
/* Clean up sessions, utmp, etc. */
cleanup_exit(255);
}
collect_children();
if (!rekeying) {
channel_after_select(readset, writeset);
if (ssh_packet_need_rekeying(ssh)) {
debug("need rekeying");
ssh->kex->done = 0;
if ((r = kex_send_kexinit(ssh)) != 0) {
fatal("%s: kex_send_kexinit: %s",
__func__, ssh_err(r));
}
}
}
process_input(ssh, readset);
if (connection_closed)
break;
process_output(ssh, writeset);
}
collect_children();
free(readset);
free(writeset);
/* free all channels, no more reads and writes */
channel_free_all();
/* free remaining sessions, e.g. remove wtmp entries */
session_destroy_all(NULL);
}
/*
* Waits for the server identification string, and sends our own
* identification string.
*/
void
ssh_exchange_identification(struct ssh *ssh, int timeout_ms)
{
char buf[256], remote_version[256]; /* must be same size! */
int remote_major, remote_minor, mismatch;
int connection_in = ssh_packet_get_connection_in(ssh);
int connection_out = ssh_packet_get_connection_out(ssh);
int minor1 = PROTOCOL_MINOR_1;
u_int i, n;
size_t len;
int fdsetsz, remaining, rc;
struct timeval t_start, t_remaining;
fd_set *fdset;
fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
fdset = xcalloc(1, fdsetsz);
/* Read other side's version identification. */
remaining = timeout_ms;
for (n = 0;;) {
for (i = 0; i < sizeof(buf) - 1; i++) {
if (timeout_ms > 0) {
gettimeofday(&t_start, NULL);
ms_to_timeval(&t_remaining, remaining);
FD_SET(connection_in, fdset);
rc = select(connection_in + 1, fdset, NULL,
fdset, &t_remaining);
ms_subtract_diff(&t_start, &remaining);
if (rc == 0 || remaining <= 0)
fatal("Connection timed out during "
"banner exchange");
if (rc == -1) {
if (errno == EINTR)
continue;
fatal("ssh_exchange_identification: "
"select: %s", strerror(errno));
}
}
len = roaming_atomicio(read, connection_in, &buf[i], 1);
if (len != 1 && errno == EPIPE)
fatal("ssh_exchange_identification: "
"Connection closed by remote host");
else if (len != 1)
fatal("ssh_exchange_identification: "
"read: %.100s", strerror(errno));
if (buf[i] == '\r') {
buf[i] = '\n';
buf[i + 1] = 0;
continue; /**XXX wait for \n */
}
if (buf[i] == '\n') {
buf[i + 1] = 0;
break;
}
if (++n > 65536)
fatal("ssh_exchange_identification: "
"No banner received");
}
buf[sizeof(buf) - 1] = 0;
if (strncmp(buf, "SSH-", 4) == 0)
break;
debug("ssh_exchange_identification: %s", buf);
}
server_version_string = xstrdup(buf);
xfree(fdset);
/*
* Check that the versions match. In future this might accept
* several versions and set appropriate flags to handle them.
*/
if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
&remote_major, &remote_minor, remote_version) != 3)
fatal("Bad remote protocol version identification: '%.100s'", buf);
debug("Remote protocol version %d.%d, remote software version %.100s",
remote_major, remote_minor, remote_version);
ssh->compat = compat_datafellows(remote_version);
mismatch = 0;
switch (remote_major) {
case 1:
if (remote_minor == 99 &&
(options.protocol & SSH_PROTO_2) &&
!(options.protocol & SSH_PROTO_1_PREFERRED)) {
enable_compat20();
break;
}
if (!(options.protocol & SSH_PROTO_1)) {
mismatch = 1;
break;
}
if (remote_minor < 3) {
fatal("Remote machine has too old SSH software version.");
} else if (remote_minor == 3 || remote_minor == 4) {
/* We speak 1.3, too. */
enable_compat13();
minor1 = 3;
if (options.forward_agent) {
logit("Agent forwarding disabled for protocol 1.3");
options.forward_agent = 0;
}
}
break;
case 2:
if (options.protocol & SSH_PROTO_2) {
enable_compat20();
break;
}
/* FALLTHROUGH */
default:
mismatch = 1;
break;
}
if (mismatch)
fatal("Protocol major versions differ: %d vs. %d",
(options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
remote_major);
/* Send our own protocol version identification. */
snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s",
compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
compat20 ? PROTOCOL_MINOR_2 : minor1,
SSH_VERSION, compat20 ? "\r\n" : "\n");
if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf))
!= strlen(buf))
fatal("write: %.100s", strerror(errno));
client_version_string = xstrdup(buf);
chop(client_version_string);
chop(server_version_string);
debug("Local version string %.100s", client_version_string);
}
/*
* 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)
{
struct ssh *ssh = active_state; /* XXX */
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_int64_t max_time_milliseconds;
u_int previous_stdout_buffer_bytes;
u_int stdout_buffer_bytes;
int r, type;
debug("Entering interactive session.");
/* Initialize the SIGCHLD kludge. */
child_terminated = 0;
signal(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 (!(ssh->compat & SSH_BUG_IGNOREMSG) && isatty(fdin))
fdin_is_tty = 1;
connection_in = ssh_packet_get_connection_in(ssh);
connection_out = ssh_packet_get_connection_out(ssh);
notify_setup();
previous_stdout_buffer_bytes = 0;
/* Set approximate I/O buffer size. */
if (ssh_packet_is_interactive(ssh))
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. */
if ((stdin_buffer = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
if ((stdout_buffer = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
if ((stderr_buffer = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
/*
* 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(ssh);
/* Main loop of the server for the interactive session mode. */
for (;;) {
/* Process buffered packets from the client. */
process_buffered_input_packets(ssh);
/*
* 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 && sshbuf_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(ssh);
/*
* 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 = sshbuf_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(ssh);
}
previous_stdout_buffer_bytes = sshbuf_len(stdout_buffer);
/* Send channel data to the client. */
if (ssh_packet_not_very_much_data_to_write(ssh))
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 && !ssh_packet_have_data_to_write(ssh) &&
sshbuf_len(stdout_buffer) == 0 && sshbuf_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 = channel_open_message();
waiting_termination = 1;
/* Display list of open channels. */
if ((r = sshbuf_put(stderr_buffer,
s, strlen(s))) != 0 ||
(r = sshbuf_put(stderr_buffer,
s, strlen(s))) != 0)
fatal("%s: buffer error: %s",
__func__, ssh_err(r));
free(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(ssh, &readset, &writeset, &max_fd,
&nalloc, max_time_milliseconds);
if (received_sigterm) {
logit("Exiting on signal %d", (int)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(ssh, readset);
/* Process output to the client and to program stdin. */
process_output(ssh, writeset);
}
free(readset);
free(writeset);
/* Cleanup and termination code. */
/* Wait until all output has been sent to the client. */
drain_output(ssh);
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. */
sshbuf_free(stdin_buffer);
sshbuf_free(stdout_buffer);
sshbuf_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. */
signal(SIGCHLD, SIG_DFL);
while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
if (errno != EINTR)
ssh_packet_disconnect(ssh, "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));
if ((r = sshpkt_start(ssh, SSH_SMSG_EXITSTATUS)) != 0 ||
(r = sshpkt_put_u32(ssh, WEXITSTATUS(wait_status))) != 0 ||
(r = sshpkt_send(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
ssh_packet_write_wait(ssh);
/*
* 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 = ssh_packet_read(ssh);
}
while (type != SSH_CMSG_EXIT_CONFIRMATION);
debug("Received exit confirmation.");
return;
}
/* Check if the program terminated due to a signal. */
if (WIFSIGNALED(wait_status))
ssh_packet_disconnect(ssh, "Command terminated on signal %d.",
WTERMSIG(wait_status));
/* Some weird exit cause. Just exit. */
ssh_packet_disconnect(ssh, "wait returned status %04x.", wait_status);
/* NOTREACHED */
}