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- 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@
This commit is contained in:
Darren Tucker 2008-06-13 04:49:33 +10:00
parent 267e28bb75
commit 2fb66caca2
6 changed files with 202 additions and 89 deletions
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12
ChangeLog
View File

@ -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]
@ -4230,4 +4240,4 @@
OpenServer 6 and add osr5bigcrypt support so when someone migrates
passwords between UnixWare and OpenServer they will still work. OK dtucker@
$Id: ChangeLog,v 1.4976 2008/06/12 18:48:11 dtucker Exp $
$Id: ChangeLog,v 1.4977 2008/06/12 18:49:33 dtucker Exp $

5
channels.c
View File

@ -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 <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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

5
channels.h
View File

@ -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 <ylo@cs.hut.fi>
@ -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);

154
clientloop.c
View File

@ -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 <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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);

22
clientloop.h
View File

@ -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 <ylo@cs.hut.fi>
@ -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 *);

93
mux.c
View File

@ -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 <djm@openbsd.org>
*
@ -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 <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
@ -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)