From f17f705b785ac9b7ae550a5307c98ad7771627e6 Mon Sep 17 00:00:00 2001 From: dtucker Date: Thu, 12 Jun 2008 18:49:33 +0000 Subject: [PATCH] - djm@cvs.openbsd.org 2008/06/12 03:40:52 [clientloop.h mux.c channels.c clientloop.c channels.h] Enable ~ escapes for multiplex slave sessions; give each channel its own escape state and hook the escape filters up to muxed channels. bz #1331 Mux slaves do not currently support the ~^Z and ~& escapes. NB. this change cranks the mux protocol version, so a new ssh mux client will not be able to connect to a running old ssh mux master. ok dtucker@ --- ChangeLog | 10 ++++ channels.c | 5 +- channels.h | 5 +- clientloop.c | 154 ++++++++++++++++++++++++++++++++++++++------------- clientloop.h | 22 ++------ mux.c | 93 ++++++++++++++++++++----------- 6 files changed, 201 insertions(+), 88 deletions(-) diff --git a/ChangeLog b/ChangeLog index 31a61b2d..15679c64 100644 --- a/ChangeLog +++ b/ChangeLog @@ -68,6 +68,16 @@ [key.c] use an odd number of rows and columns and a separate start marker, looks better; ok grunk@ + - djm@cvs.openbsd.org 2008/06/12 03:40:52 + [clientloop.h mux.c channels.c clientloop.c channels.h] + Enable ~ escapes for multiplex slave sessions; give each channel + its own escape state and hook the escape filters up to muxed + channels. bz #1331 + Mux slaves do not currently support the ~^Z and ~& escapes. + NB. this change cranks the mux protocol version, so a new ssh + mux client will not be able to connect to a running old ssh + mux master. + ok dtucker@ 20080611 - (djm) [channels.c configure.ac] diff --git a/channels.c b/channels.c index 233c2247..c539990f 100644 --- a/channels.c +++ b/channels.c @@ -1,4 +1,4 @@ -/* $OpenBSD: channels.c,v 1.278 2008/06/10 04:50:25 dtucker Exp $ */ +/* $OpenBSD: channels.c,v 1.279 2008/06/12 03:40:52 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -731,7 +731,7 @@ channel_cancel_cleanup(int id) void channel_register_filter(int id, channel_infilter_fn *ifn, - channel_outfilter_fn *ofn) + channel_outfilter_fn *ofn, void *ctx) { Channel *c = channel_lookup(id); @@ -741,6 +741,7 @@ channel_register_filter(int id, channel_infilter_fn *ifn, } c->input_filter = ifn; c->output_filter = ofn; + c->filter_ctx = ctx; } void diff --git a/channels.h b/channels.h index dc1f483e..450321d4 100644 --- a/channels.h +++ b/channels.h @@ -1,4 +1,4 @@ -/* $OpenBSD: channels.h,v 1.93 2008/06/10 04:50:25 dtucker Exp $ */ +/* $OpenBSD: channels.h,v 1.94 2008/06/12 03:40:52 djm Exp $ */ /* * Author: Tatu Ylonen @@ -131,6 +131,7 @@ struct Channel { /* filter */ channel_infilter_fn *input_filter; channel_outfilter_fn *output_filter; + void *filter_ctx; /* keep boundaries */ int datagram; @@ -195,7 +196,7 @@ void channel_request_start(int, char *, int); void channel_register_cleanup(int, channel_callback_fn *, int); void channel_register_open_confirm(int, channel_callback_fn *, void *); void channel_register_filter(int, channel_infilter_fn *, - channel_outfilter_fn *); + channel_outfilter_fn *, void *); void channel_register_status_confirm(int, channel_confirm_cb *, channel_confirm_abandon_cb *, void *); void channel_cancel_cleanup(int); diff --git a/clientloop.c b/clientloop.c index 3bc8bb8d..b45e7298 100644 --- a/clientloop.c +++ b/clientloop.c @@ -1,4 +1,4 @@ -/* $OpenBSD: clientloop.c,v 1.194 2008/05/19 20:53:52 djm Exp $ */ +/* $OpenBSD: clientloop.c,v 1.195 2008/06/12 03:40:52 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -144,8 +144,8 @@ static int in_non_blocking_mode = 0; /* Common data for the client loop code. */ static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ -static int escape_char; /* Escape character. */ -static int escape_pending; /* Last character was the escape character */ +static int escape_char1; /* Escape character. (proto1 only) */ +static int escape_pending1; /* Last character was an escape (proto1 only) */ static int last_was_cr; /* Last character was a newline. */ static int exit_status; /* Used to store the exit status of the command. */ static int stdin_eof; /* EOF has been encountered on standard error. */ @@ -162,6 +162,13 @@ static int session_closed = 0; /* In SSH2: login session closed. */ static void client_init_dispatch(void); int session_ident = -1; +/* Track escape per proto2 channel */ +struct escape_filter_ctx { + int escape_pending; + int escape_char; +}; + +/* Context for channel confirmation replies */ struct channel_reply_ctx { const char *request_type; int id, do_close; @@ -385,8 +392,8 @@ client_check_initial_eof_on_stdin(void) * and also process it as an escape character if * appropriate. */ - if ((u_char) buf[0] == escape_char) - escape_pending = 1; + if ((u_char) buf[0] == escape_char1) + escape_pending1 = 1; else buffer_append(&stdin_buffer, buf, 1); } @@ -813,9 +820,12 @@ out: xfree(fwd.connect_host); } -/* process the characters one by one */ +/* + * Process the characters one by one, call with c==NULL for proto1 case. + */ static int -process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) +process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, + char *buf, int len) { char string[1024]; pid_t pid; @@ -823,7 +833,20 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) u_int i; u_char ch; char *s; + int *escape_pendingp, escape_char; + struct escape_filter_ctx *efc; + if (c == NULL) { + escape_pendingp = &escape_pending1; + escape_char = escape_char1; + } else { + if (c->filter_ctx == NULL) + return 0; + efc = (struct escape_filter_ctx *)c->filter_ctx; + escape_pendingp = &efc->escape_pending; + escape_char = efc->escape_char; + } + if (len <= 0) return (0); @@ -831,25 +854,43 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) /* Get one character at a time. */ ch = buf[i]; - if (escape_pending) { + if (*escape_pendingp) { /* We have previously seen an escape character. */ /* Clear the flag now. */ - escape_pending = 0; + *escape_pendingp = 0; /* Process the escaped character. */ switch (ch) { case '.': /* Terminate the connection. */ - snprintf(string, sizeof string, "%c.\r\n", escape_char); + snprintf(string, sizeof string, "%c.\r\n", + escape_char); buffer_append(berr, string, strlen(string)); - quit_pending = 1; + if (c && c->ctl_fd != -1) { + chan_read_failed(c); + chan_write_failed(c); + return 0; + } else + quit_pending = 1; return -1; case 'Z' - 64: + /* XXX support this for mux clients */ + if (c && c->ctl_fd != -1) { + noescape: + snprintf(string, sizeof string, + "%c%c escape not available to " + "multiplexed sessions\r\n", + escape_char, ch); + buffer_append(berr, string, + strlen(string)); + continue; + } /* Suspend the program. */ /* Print a message to that effect to the user. */ - snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); + snprintf(string, sizeof string, + "%c^Z [suspend ssh]\r\n", escape_char); buffer_append(berr, string, strlen(string)); /* Restore terminal modes and suspend. */ @@ -881,6 +922,8 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) continue; case '&': + if (c && c->ctl_fd != -1) + goto noescape; /* * Detach the program (continue to serve connections, * but put in background and no more new connections). @@ -929,27 +972,50 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) continue; case '?': - snprintf(string, sizeof string, + if (c && c->ctl_fd != -1) { + snprintf(string, sizeof string, "%c?\r\n\ Supported escape sequences:\r\n\ -%c. - terminate connection\r\n\ -%cB - send a BREAK to the remote system\r\n\ -%cC - open a command line\r\n\ -%cR - Request rekey (SSH protocol 2 only)\r\n\ -%c^Z - suspend ssh\r\n\ -%c# - list forwarded connections\r\n\ -%c& - background ssh (when waiting for connections to terminate)\r\n\ -%c? - this message\r\n\ -%c%c - send the escape character by typing it twice\r\n\ + %c. - terminate session\r\n\ + %cB - send a BREAK to the remote system\r\n\ + %cC - open a command line\r\n\ + %cR - Request rekey (SSH protocol 2 only)\r\n\ + %c# - list forwarded connections\r\n\ + %c? - this message\r\n\ + %c%c - send the escape character by typing it twice\r\n\ (Note that escapes are only recognized immediately after newline.)\r\n", - escape_char, escape_char, escape_char, escape_char, - escape_char, escape_char, escape_char, escape_char, - escape_char, escape_char, escape_char); + escape_char, escape_char, + escape_char, escape_char, + escape_char, escape_char, + escape_char, escape_char, + escape_char); + } else { + snprintf(string, sizeof string, +"%c?\r\n\ +Supported escape sequences:\r\n\ + %c. - terminate connection (and any multiplexed sessions)\r\n\ + %cB - send a BREAK to the remote system\r\n\ + %cC - open a command line\r\n\ + %cR - Request rekey (SSH protocol 2 only)\r\n\ + %c^Z - suspend ssh\r\n\ + %c# - list forwarded connections\r\n\ + %c& - background ssh (when waiting for connections to terminate)\r\n\ + %c? - this message\r\n\ + %c%c - send the escape character by typing it twice\r\n\ +(Note that escapes are only recognized immediately after newline.)\r\n", + escape_char, escape_char, + escape_char, escape_char, + escape_char, escape_char, + escape_char, escape_char, + escape_char, escape_char, + escape_char); + } buffer_append(berr, string, strlen(string)); continue; case '#': - snprintf(string, sizeof string, "%c#\r\n", escape_char); + snprintf(string, sizeof string, "%c#\r\n", + escape_char); buffer_append(berr, string, strlen(string)); s = channel_open_message(); buffer_append(berr, s, strlen(s)); @@ -975,7 +1041,7 @@ Supported escape sequences:\r\n\ */ if (last_was_cr && ch == escape_char) { /* It is. Set the flag and continue to next character. */ - escape_pending = 1; + *escape_pendingp = 1; continue; } } @@ -1026,7 +1092,7 @@ client_process_input(fd_set *readset) packet_start(SSH_CMSG_EOF); packet_send(); } - } else if (escape_char == SSH_ESCAPECHAR_NONE) { + } else if (escape_char1 == SSH_ESCAPECHAR_NONE) { /* * Normal successful read, and no escape character. * Just append the data to buffer. @@ -1037,8 +1103,8 @@ client_process_input(fd_set *readset) * Normal, successful read. But we have an escape character * and have to process the characters one by one. */ - if (process_escapes(&stdin_buffer, &stdout_buffer, - &stderr_buffer, buf, len) == -1) + if (process_escapes(NULL, &stdin_buffer, + &stdout_buffer, &stderr_buffer, buf, len) == -1) return; } } @@ -1113,13 +1179,26 @@ client_process_buffered_input_packets(void) /* scan buf[] for '~' before sending data to the peer */ -static int -simple_escape_filter(Channel *c, char *buf, int len) +/* Helper: allocate a new escape_filter_ctx and fill in its escape char */ +void * +client_new_escape_filter_ctx(int escape_char) +{ + struct escape_filter_ctx *ret; + + ret = xmalloc(sizeof(*ret)); + ret->escape_pending = 0; + ret->escape_char = escape_char; + return (void *)ret; +} + +int +client_simple_escape_filter(Channel *c, char *buf, int len) { if (c->extended_usage != CHAN_EXTENDED_WRITE) return 0; - return process_escapes(&c->input, &c->output, &c->extended, buf, len); + return process_escapes(c, &c->input, &c->output, &c->extended, + buf, len); } static void @@ -1151,7 +1230,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) start_time = get_current_time(); /* Initialize variables. */ - escape_pending = 0; + escape_pending1 = 0; last_was_cr = 1; exit_status = -1; stdin_eof = 0; @@ -1178,7 +1257,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) stdout_bytes = 0; stderr_bytes = 0; quit_pending = 0; - escape_char = escape_char_arg; + escape_char1 = escape_char_arg; /* Initialize buffers. */ buffer_init(&stdin_buffer); @@ -1206,9 +1285,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) if (compat20) { session_ident = ssh2_chan_id; - if (escape_char != SSH_ESCAPECHAR_NONE) + if (escape_char_arg != SSH_ESCAPECHAR_NONE) channel_register_filter(session_ident, - simple_escape_filter, NULL); + client_simple_escape_filter, NULL, + client_new_escape_filter_ctx(escape_char_arg)); if (session_ident != -1) channel_register_cleanup(session_ident, client_channel_closed, 0); diff --git a/clientloop.h b/clientloop.h index 6f8e7012..cecbfb1a 100644 --- a/clientloop.h +++ b/clientloop.h @@ -1,4 +1,4 @@ -/* $OpenBSD: clientloop.h,v 1.19 2008/05/09 14:18:44 djm Exp $ */ +/* $OpenBSD: clientloop.h,v 1.20 2008/06/12 03:40:52 djm Exp $ */ /* * Author: Tatu Ylonen @@ -46,8 +46,12 @@ void client_session2_setup(int, int, int, const char *, struct termios *, int, Buffer *, char **); int client_request_tun_fwd(int, int, int); +/* Escape filter for protocol 2 sessions */ +void *client_new_escape_filter_ctx(int); +int client_simple_escape_filter(Channel *, char *, int); + /* Multiplexing protocol version */ -#define SSHMUX_VER 1 +#define SSHMUX_VER 2 /* Multiplexing control protocol flags */ #define SSHMUX_COMMAND_OPEN 1 /* Open new connection */ @@ -59,20 +63,6 @@ int client_request_tun_fwd(int, int, int); #define SSHMUX_FLAG_X11_FWD (1<<2) /* Request X11 forwarding */ #define SSHMUX_FLAG_AGENT_FWD (1<<3) /* Request agent forwarding */ -/* Multiplexing routines */ - -struct mux_session_confirm_ctx { - int want_tty; - int want_subsys; - int want_x_fwd; - int want_agent_fwd; - Buffer cmd; - char *term; - struct termios tio; - char **env; -}; - -/* mux.c */ void muxserver_listen(void); int muxserver_accept_control(void); void muxclient(const char *); diff --git a/mux.c b/mux.c index 8b9105b0..efc3840c 100644 --- a/mux.c +++ b/mux.c @@ -1,4 +1,4 @@ -/* $OpenBSD: mux.c,v 1.1 2008/05/09 14:18:44 djm Exp $ */ +/* $OpenBSD: mux.c,v 1.2 2008/06/12 03:40:52 djm Exp $ */ /* * Copyright (c) 2002-2008 Damien Miller * @@ -19,6 +19,20 @@ #include "includes.h" +/* + * TODO: + * 1. partial reads in muxserver_accept_control (maybe make channels + * from accepted connections) + * 2. Better signalling from master to slave, especially passing of + * error messages + * 3. Better fall-back from mux slave error to new connection. + * 3. Add/delete forwardings via slave + * 4. ExitOnForwardingFailure (after #3 obviously) + * 5. Maybe extension mechanisms for multi-X11/multi-agent forwarding + * 6. Document the mux mini-protocol somewhere. + * 6. Support ~^Z in mux slaves. + */ + #include #include #include @@ -71,6 +85,18 @@ extern char *host; int subsystem_flag; extern Buffer command; +/* Context for session open confirmation callback */ +struct mux_session_confirm_ctx { + int want_tty; + int want_subsys; + int want_x_fwd; + int want_agent_fwd; + Buffer cmd; + char *term; + struct termios tio; + char **env; +}; + /* fd to control socket */ int muxserver_sock = -1; @@ -131,7 +157,7 @@ muxserver_listen(void) /* Callback on open confirmation in mux master for a mux client session. */ static void -client_extra_session2_setup(int id, void *arg) +mux_session_confirm(int id, void *arg) { struct mux_session_confirm_ctx *cctx = arg; const char *display; @@ -190,7 +216,7 @@ muxserver_accept_control(void) struct sockaddr_storage addr; struct mux_session_confirm_ctx *cctx; char *cmd; - u_int i, j, len, env_len, mux_command, flags; + u_int i, j, len, env_len, mux_command, flags, escape_char; uid_t euid; gid_t egid; int start_close = 0; @@ -317,6 +343,7 @@ muxserver_accept_control(void) cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0; cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0; cctx->term = buffer_get_string(&m, &len); + escape_char = buffer_get_int(&m); cmd = buffer_get_string(&m, &len); buffer_init(&cctx->cmd); @@ -402,14 +429,17 @@ muxserver_accept_control(void) new_fd[0], new_fd[1], new_fd[2], window, packetmax, CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); - /* XXX */ c->ctl_fd = client_fd; + if (cctx->want_tty && escape_char != 0xffffffff) { + channel_register_filter(c->self, + client_simple_escape_filter, NULL, + client_new_escape_filter_ctx((int)escape_char)); + } debug3("%s: channel_new: %d", __func__, c->self); channel_send_open(c->self); - channel_register_open_confirm(c->self, - client_extra_session2_setup, cctx); + channel_register_open_confirm(c->self, mux_session_confirm, cctx); return 0; } @@ -561,33 +591,34 @@ muxclient(const char *path) fprintf(stderr, "Exit request sent.\r\n"); exit(0); case SSHMUX_COMMAND_OPEN: - /* continue below */ + buffer_put_cstring(&m, term ? term : ""); + if (options.escape_char == SSH_ESCAPECHAR_NONE) + buffer_put_int(&m, 0xffffffff); + else + buffer_put_int(&m, options.escape_char); + buffer_append(&command, "\0", 1); + buffer_put_cstring(&m, buffer_ptr(&command)); + + if (options.num_send_env == 0 || environ == NULL) { + buffer_put_int(&m, 0); + } else { + /* Pass environment */ + num_env = 0; + for (i = 0; environ[i] != NULL; i++) { + if (env_permitted(environ[i])) + num_env++; /* Count */ + } + buffer_put_int(&m, num_env); + for (i = 0; environ[i] != NULL && num_env >= 0; i++) { + if (env_permitted(environ[i])) { + num_env--; + buffer_put_cstring(&m, environ[i]); + } + } + } break; default: - fatal("silly muxclient_command %d", muxclient_command); - } - - /* SSHMUX_COMMAND_OPEN */ - buffer_put_cstring(&m, term ? term : ""); - buffer_append(&command, "\0", 1); - buffer_put_cstring(&m, buffer_ptr(&command)); - - if (options.num_send_env == 0 || environ == NULL) { - buffer_put_int(&m, 0); - } else { - /* Pass environment */ - num_env = 0; - for (i = 0; environ[i] != NULL; i++) - if (env_permitted(environ[i])) - num_env++; /* Count */ - - buffer_put_int(&m, num_env); - - for (i = 0; environ[i] != NULL && num_env >= 0; i++) - if (env_permitted(environ[i])) { - num_env--; - buffer_put_cstring(&m, environ[i]); - } + fatal("unrecognised muxclient_command %d", muxclient_command); } if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) -- 2.45.2