+/* $OpenBSD: serverloop.c,v 1.159 2009/05/28 16:50:16 andreas Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*/
#include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.111 2003/09/23 20:17:11 markus Exp $");
+#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 "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "packet.h"
#include "buffer.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"
-#include "kex.h"
+#include "roaming.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 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;
+static int no_more_sessions = 0; /* Disallow further sessions. */
/*
* This SIGCHLD kludge is used to detect when the child exits. The server
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);
debug2("notify_done: reading");
}
+/*ARGSUSED*/
static void
sigchld_handler(int sig)
{
int save_errno = errno;
- debug("Received SIGCHLD.");
child_terminated = 1;
#ifndef _UNICOS
mysignal(SIGCHLD, sigchld_handler);
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
client_alive_check(void)
{
- static int had_channel = 0;
- int id;
-
- id = channel_find_open();
- if (id == -1) {
- if (!had_channel)
- return;
- packet_disconnect("No open channels after timeout!");
- }
- had_channel = 1;
+ 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.");
+ if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
+ logit("Timeout, client not responding.");
+ cleanup_exit(255);
+ }
/*
- * send a bogus channel request with "wantreply",
+ * send a bogus global/channel request with "wantreply",
* we should get back a failure
*/
- channel_request_start(id, "keepalive@openssh.com", 1);
+ 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();
}
*/
static void
wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
- int *nallocp, u_int max_time_milliseconds)
+ u_int *nallocp, u_int max_time_milliseconds)
{
struct timeval tv, *tvp;
int ret;
int client_alive_scheduled = 0;
+ int program_alive_scheduled = 0;
/*
* if using client_alive, set the max timeout accordingly,
* the client, try to get some more data from the program.
*/
if (packet_not_very_much_data_to_write()) {
+ program_alive_scheduled = child_terminated;
if (!fdout_eof)
FD_SET(fdout, *readsetp);
if (!fderr_eof)
memset(*writesetp, 0, *nallocp);
if (errno != EINTR)
error("select: %.100s", strerror(errno));
- } else if (ret == 0 && client_alive_scheduled)
- client_alive_check();
+ } else {
+ if (ret == 0 && client_alive_scheduled)
+ client_alive_check();
+ if (!compat20 && program_alive_scheduled && fdin_is_tty) {
+ if (!fdout_eof)
+ FD_SET(fdout, *readsetp);
+ if (!fderr_eof)
+ FD_SET(fderr, *readsetp);
+ }
+ }
notify_done(*readsetp);
}
* in buffers and processed later.
*/
static void
-process_input(fd_set * readset)
+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));
+ int cont = 0;
+ len = roaming_read(connection_in, buf, sizeof(buf), &cont);
if (len == 0) {
+ if (cont)
+ return;
verbose("Connection closed by %.100s",
get_remote_ipaddr());
connection_closed = 1;
return;
cleanup_exit(255);
} else if (len < 0) {
- if (errno != EINTR && errno != EAGAIN) {
+ if (errno != EINTR && errno != EAGAIN &&
+ errno != EWOULDBLOCK) {
verbose("Read error from remote host "
"%.100s: %.100s",
get_remote_ipaddr(), strerror(errno));
/* 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)) {
+ if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
+ errno == EWOULDBLOCK) && !child_terminated))) {
/* 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);
}
/* 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)) {
+ if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
+ errno == EWOULDBLOCK) && !child_terminated))) {
/* 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)
+process_output(fd_set *writeset)
{
struct termios tio;
u_char *data;
data = buffer_ptr(&stdin_buffer);
dlen = buffer_len(&stdin_buffer);
len = write(fdin, data, dlen);
- if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
+ if (len < 0 &&
+ (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
/* do nothing */
} else if (len <= 0) {
if (fdin != fdout)
server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
{
fd_set *readset = NULL, *writeset = NULL;
- int max_fd = 0, nalloc = 0;
+ 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. */
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;
* 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.
+ * we don't need to check the descriptor everywhere.
*/
if (fderr == -1)
fderr_eof = 1;
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);
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)
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);
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);
}
static void
-server_input_channel_failure(int type, u_int32_t seq, void *ctxt)
+server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
{
- debug("Got CHANNEL_FAILURE for keepalive");
+ 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;
+ packet_set_alive_timeouts(0);
}
-
static void
server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
{
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();
+ 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();
}
static Channel *
-server_request_direct_tcpip(char *ctype)
+server_request_direct_tcpip(void)
{
Channel *c;
- int sock;
char *target, *originator;
- int target_port, originator_port;
+ u_short target_port, originator_port;
target = packet_get_string(NULL);
target_port = packet_get_int();
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);
+ 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);
+ c = channel_connect_to(target, target_port,
+ "direct-tcpip", "direct-tcpip");
+
xfree(originator);
- if (sock < 0)
+ xfree(target);
+
+ 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;
- c = channel_new(ctype, SSH_CHANNEL_CONNECTING,
- sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
- CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
+ }
+
+ 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, NULL, NULL);
+#endif
+
+ done:
+ if (c == NULL)
+ packet_send_debug("Failed to open the tunnel device.");
return c;
}
static Channel *
-server_request_session(char *ctype)
+server_request_session(void)
{
Channel *c;
debug("input_session_request");
packet_check_eom();
+
+ if (no_more_sessions) {
+ packet_disconnect("Possible attack: attempt to open a session "
+ "after additional sessions disabled");
+ }
+
/*
* 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(ctype, SSH_CHANNEL_LARVAL,
+ 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) {
channel_free(c);
return NULL;
}
- channel_register_cleanup(c->self, session_close_by_channel);
+ channel_register_cleanup(c->self, session_close_by_channel, 0);
return c;
}
ctype, rchan, rwindow, rmaxpack);
if (strcmp(ctype, "session") == 0) {
- c = server_request_session(ctype);
+ c = server_request_session();
} else if (strcmp(ctype, "direct-tcpip") == 0) {
- c = server_request_direct_tcpip(ctype);
+ 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);
{
char *rtype;
int want_reply;
- int success = 0;
+ int success = 0, allocated_listen_port = 0;
rtype = packet_get_string(NULL);
want_reply = packet_get_char();
u_short listen_port;
pw = the_authctxt->pw;
- if (pw == NULL)
- fatal("server_input_global_request: no user");
+ 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",
/* check permissions */
if (!options.allow_tcp_forwarding ||
- no_port_forwarding_flag
+ no_port_forwarding_flag ||
+ (!want_reply && listen_port == 0)
#ifndef NO_IPPORT_RESERVED_CONCEPT
- || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
+ || (listen_port != 0 && 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);
+ listen_address, listen_port,
+ &allocated_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);
+ } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
+ no_more_sessions = 1;
+ success = 1;
}
if (want_reply) {
packet_start(success ?
SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
+ if (success && allocated_listen_port > 0)
+ packet_put_int(allocated_listen_port);
packet_send();
packet_write_wait();
}
xfree(rtype);
}
+
static void
server_input_channel_req(int type, u_int32_t seq, void *ctxt)
{
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)
+ if (!strcmp(rtype, "eow@openssh.com")) {
+ packet_check_eom();
+ chan_rcvd_eow(c);
+ } else if ((c->type == SSH_CHANNEL_LARVAL ||
+ c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
success = session_input_channel_req(c, rtype);
if (reply) {
packet_start(success ?
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_channel_failure);
+ dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_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);
}
andersk / openssh.git / blobdiff