1 files changed, 37 insertions, 23 deletions

diff --git a/serverloop.c b/serverloop.c
index 29ffcfee1..6a3e2af10 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.145 2006/10/11 12:38:03 markus Exp $ */
+/* $OpenBSD: serverloop.c,v 1.153 2008/06/30 12:15:39 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -56,6 +56,7 @@
 #include <unistd.h>
 #include <stdarg.h>
 
+#include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "packet.h"
 #include "buffer.h"
@@ -104,7 +105,7 @@ 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;
+static int no_more_sessions = 0; /* Disallow further sessions. */
 
 /*
  * This SIGCHLD kludge is used to detect when the child exits.  The server
@@ -248,7 +249,7 @@ 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) {
+        if (++keep_alive_timeouts > options.client_alive_count_max) {
                 logit("Timeout, client not responding.");
                 cleanup_exit(255);
         }
@@ -399,7 +400,8 @@ process_input(fd_set *readset)
                                 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));
@@ -417,8 +419,8 @@ process_input(fd_set *readset)
         if (!fdout_eof && FD_ISSET(fdout, readset)) {
                 errno = 0;
                 len = read(fdout, buf, sizeof(buf));
-                if (len < 0 && (errno == EINTR ||
-                    (errno == EAGAIN && !child_terminated))) {
+                if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
+                    errno == EWOULDBLOCK) && !child_terminated))) {
                         /* do nothing */
 #ifndef PTY_ZEROREAD
                 } else if (len <= 0) {
@@ -436,8 +438,8 @@ process_input(fd_set *readset)
         if (!fderr_eof && FD_ISSET(fderr, readset)) {
                 errno = 0;
                 len = read(fderr, buf, sizeof(buf));
-                if (len < 0 && (errno == EINTR ||
-                    (errno == EAGAIN && !child_terminated))) {
+                if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
+                    errno == EWOULDBLOCK) && !child_terminated))) {
                         /* do nothing */
 #ifndef PTY_ZEROREAD
                 } else if (len <= 0) {
@@ -468,7 +470,8 @@ process_output(fd_set *writeset)
                 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)
@@ -887,7 +890,7 @@ server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
          * even if this was generated by something other than
          * the bogus CHANNEL_REQUEST we send for keepalives.
          */
-        client_alive_timeouts = 0;
+        keep_alive_timeouts = 0;
 }
 
 static void
@@ -938,7 +941,6 @@ static Channel *
 server_request_direct_tcpip(void)
 {
         Channel *c;
-        int sock;
         char *target, *originator;
         int target_port, originator_port;
 
@@ -948,18 +950,16 @@ server_request_direct_tcpip(void)
         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)
-                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);
+        xfree(target);
+
         return c;
 }
 
@@ -1000,7 +1000,7 @@ server_request_tun(void)
 #if defined(SSH_TUN_FILTER)
         if (mode == SSH_TUNMODE_POINTOPOINT)
                 channel_register_filter(c->self, sys_tun_infilter,
-                    sys_tun_outfilter);
+                    sys_tun_outfilter, NULL, NULL);
 #endif
 
  done:
@@ -1016,6 +1016,12 @@ server_request_session(void)
 
         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
@@ -1136,6 +1142,9 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt)
                 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 ?
@@ -1163,7 +1172,11 @@ 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 ?
@@ -1189,8 +1202,9 @@ server_init_dispatch_20(void)
         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);
+        dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
+        dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
         /* 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 */