X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/e914f53ae82f35cba59b29370ceabbe8d1446f12..HEAD:/serverloop.c diff --git a/serverloop.c b/serverloop.c index 3d8e7cfb..8be01c5c 100644 --- a/serverloop.c +++ b/serverloop.c @@ -1,3 +1,4 @@ +/* $OpenBSD: serverloop.c,v 1.159 2009/05/28 16:50:16 andreas Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -35,8 +36,27 @@ */ #include "includes.h" -RCSID("$OpenBSD: serverloop.c,v 1.124 2005/12/13 15:03:02 reyk Exp $"); +#include +#include +#include +#include +#ifdef HAVE_SYS_TIME_H +# include +#endif + +#include + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "openbsd-compat/sys-queue.h" #include "xmalloc.h" #include "packet.h" #include "buffer.h" @@ -48,13 +68,17 @@ RCSID("$OpenBSD: serverloop.c,v 1.124 2005/12/13 15:03:02 reyk Exp $"); #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; @@ -82,7 +106,7 @@ 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 @@ -142,11 +166,11 @@ notify_done(fd_set *readset) 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); @@ -155,6 +179,7 @@ sigchld_handler(int sig) errno = save_errno; } +/*ARGSUSED*/ static void sigterm_handler(int sig) { @@ -225,8 +250,10 @@ 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."); + if (packet_inc_alive_timeouts() > options.client_alive_count_max) { + logit("Timeout, client not responding."); + cleanup_exit(255); + } /* * send a bogus global/channel request with "wantreply", @@ -255,6 +282,7 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 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, @@ -292,6 +320,7 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, * 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) @@ -337,8 +366,16 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 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); } @@ -348,15 +385,18 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, * 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; @@ -364,7 +404,8 @@ 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)); @@ -380,10 +421,17 @@ process_input(fd_set * readset) /* 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); @@ -392,10 +440,17 @@ process_input(fd_set * readset) } /* 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); @@ -407,7 +462,7 @@ process_input(fd_set * readset) * 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; @@ -419,7 +474,8 @@ 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) @@ -749,6 +805,7 @@ collect_children(void) 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) @@ -837,7 +894,7 @@ 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; + packet_set_alive_timeouts(0); } static void @@ -873,10 +930,10 @@ server_input_eof(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(); @@ -888,9 +945,8 @@ static Channel * 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(); @@ -898,18 +954,16 @@ 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; } @@ -937,7 +991,7 @@ server_request_tun(void) tun = packet_get_int(); if (forced_tun_device != -1) { - if (tun != SSH_TUNID_ANY && forced_tun_device != tun) + if (tun != SSH_TUNID_ANY && forced_tun_device != tun) goto done; tun = forced_tun_device; } @@ -950,7 +1004,7 @@ 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: @@ -966,6 +1020,12 @@ 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 @@ -1039,7 +1099,7 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt) { 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(); @@ -1061,9 +1121,11 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt) /* 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; @@ -1071,7 +1133,8 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt) } 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) { @@ -1085,15 +1148,22 @@ 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 ? 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) { @@ -1111,7 +1181,11 @@ 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 ? @@ -1138,6 +1212,7 @@ server_init_dispatch_20(void) 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_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);