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openbsd-src/usr.bin/ssh/channels.h

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don't start the ObscureKeystrokeTiming mitigations if there has been traffic on a X11 forwarding channel recently. Should fix X11 forwarding performance problems when this setting is enabled. Patch from Antonio Larrosa via bz3655
2024-10-13 15:20:06 -07:00
/* $OpenBSD: channels.h,v 1.158 2024/10/13 22:20:06 djm Exp $ */
$OpenBSD$ and RCSID() cleanup: don't use RCSID() in .h files; add missing RCSID() to .c files and remove dup /*$OpenBSD$*/ from .c files. ok markus@
2002-03-04 09:27:39 -08:00
some more Copyright fixes
2000-09-07 14:13:36 -07:00
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
cleanup copyright notices on all files. I have attempted to be accurate with the details. everything is now under Tatu's licence (which I copied from his readme), and/or the core-sdi bsd-ish thing for deattack, or various openbsd developers under a 2-term bsd licence. We're not changing any rules, just being accurate.
2000-09-07 13:27:48 -07:00
/*
(c) 2002
2002-01-14 05:57:03 -08:00
* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
cleanup copyright notices on all files. I have attempted to be accurate with the details. everything is now under Tatu's licence (which I copied from his readme), and/or the core-sdi bsd-ish thing for deattack, or various openbsd developers under a 2-term bsd licence. We're not changing any rules, just being accurate.
2000-09-07 13:27:48 -07:00
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
add CVS tags, fix comments and whitespace
1999-10-16 15:29:00 -07:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
#ifndef CHANNEL_H
#define CHANNEL_H
support for SSH protocol 1.5 which is poorly documented, the RFC.troff lies. interops (x11,agent,etc) with 1.2.27 and protocol 1.3
1999-10-16 13:47:13 -07:00
/* Definitions for channel types. */
KNF, final part 3
1999-11-24 11:53:43 -08:00
#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
much more KNF
1999-11-23 16:26:00 -08:00
#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
KNF, final part 3
1999-11-24 11:53:43 -08:00
#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
#define SSH_CHANNEL_LARVAL 10 /* larval session */
agent forwarding and -R for ssh2, based on work from jhuuskon@messi.uku.fi
2000-11-06 15:04:55 -08:00
#define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */
async connects for -R/-L; ok deraadt@
2000-12-05 12:34:09 -08:00
#define SSH_CHANNEL_CONNECTING 12
allow the ssh client act as a SOCKS4 proxy (dynamic local portforwarding). work by Dan Kaminsky <dankamin@cisco.com> and me. thanks to Dan for this great patch: use 'ssh -D 1080 host' and make netscape use localhost:1080 as a socks proxy.
2001-04-07 01:55:15 -07:00
#define SSH_CHANNEL_DYNAMIC 13
undo broken channel fix and try a different one. there should be still some select errors...
2001-05-28 16:14:49 -07:00
#define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
#define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */
some language improvements; ok markus
2020-07-05 16:59:45 -07:00
#define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux client */
Add an "ABANDONED" channel state and use for mux sessions that are disconnected via the ~. escape sequence. Channels in this state will be able to close if the server responds, but do not count as active channels. This means that if you ~. all of the mux clients when using ControlPersist on a broken network, the backgrounded mux master will exit when the Control Persist time expires rather than hanging around indefinitely. bz#1917, also reported and tested by tedu@. ok djm@ markus@.
2013-06-07 08:37:52 -07:00
#define SSH_CHANNEL_ABANDONED 17 /* Abandoned session, eg mux */
Add support for Unix domain socket forwarding. A remote TCP port may be forwarded to a local Unix domain socket and vice versa or both ends may be a Unix domain socket. This is a reimplementation of the streamlocal patches by William Ahern from: http://www.25thandclement.com/~william/projects/streamlocal.html OK djm@ markus@
2014-07-15 08:54:14 -07:00
#define SSH_CHANNEL_UNIX_LISTENER 18 /* Listening on a domain socket. */
#define SSH_CHANNEL_RUNIX_LISTENER 19 /* Listening to a R-style domain socket. */
some language improvements; ok markus
2020-07-05 16:59:45 -07:00
#define SSH_CHANNEL_MUX_PROXY 20 /* proxy channel for mux-client */
Add 'reverse' dynamic forwarding which combines dynamic forwarding (-D) with remote forwarding (-R) where the remote-forwarded port expects SOCKS-requests. The SSH server code is unchanged and the parsing happens at the SSH clients side. Thus the full SOCKS-request is sent over the forwarded channel and the client parses c->output. Parsing happens in channel_before_prepare_select(), _before_ the select bitmask is computed in the pre[] handlers, but after network input processing in the post[] handlers. help and ok djm@
2017-09-21 12:16:53 -07:00
#define SSH_CHANNEL_RDYNAMIC_OPEN 21 /* reverse SOCKS, parsing request */
#define SSH_CHANNEL_RDYNAMIC_FINISH 22 /* reverse SOCKS, finishing connect */
#define SSH_CHANNEL_MAX_TYPE 23
support for SSH protocol 1.5 which is poorly documented, the RFC.troff lies. interops (x11,agent,etc) with 1.2.27 and protocol 1.3
1999-10-16 13:47:13 -07:00
support cancellation of local/dynamic forwardings from ~C commandline; ok & feedback djm@
2011-09-10 15:26:34 -07:00
#define CHANNEL_CANCEL_PORT_STATIC -1
restore blocking status on stdio fds before close ssh(1) needs to set file descriptors to non-blocking mode to operate but it was not restoring the original state on exit. This could cause problems with fds shared with other programs via the shell, e.g. > $ cat > test.sh << _EOF > #!/bin/sh > { > ssh -Fnone -oLogLevel=verbose ::1 hostname > cat /usr/share/dict/words > } | sleep 10 > _EOF > $ ./test.sh > Authenticated to ::1 ([::1]:22). > Transferred: sent 2352, received 2928 bytes, in 0.1 seconds > Bytes per second: sent 44338.9, received 55197.4 > cat: stdout: Resource temporarily unavailable This restores the blocking status for fds 0,1,2 (stdio) before ssh(1) abandons/closes them. This was reported as bz3280 and GHPR246; ok dtucker@
2021-05-18 18:24:05 -07:00
/* nonblocking flags for channel_new */
#define CHANNEL_NONBLOCK_LEAVE 0 /* don't modify non-blocking state */
#define CHANNEL_NONBLOCK_SET 1 /* set non-blocking state */
#define CHANNEL_NONBLOCK_STDIO 2 /* set non-blocking and restore on close */
/* c->restore_block mask flags */
#define CHANNEL_RESTORE_RFD 0x01
#define CHANNEL_RESTORE_WFD 0x02
#define CHANNEL_RESTORE_EFD 0x04
Add a PermitListen directive to control which server-side addresses may be listened on when the client requests remote forwarding (ssh -R). This is the converse of the existing PermitOpen directive and this includes some refactoring to share much of its implementation. feedback and ok markus@
2018-06-06 11:22:41 -07:00
/* TCP forwarding */
#define FORWARD_DENY 0
#define FORWARD_REMOTE (1)
#define FORWARD_LOCAL (1<<1)
#define FORWARD_ALLOW (FORWARD_REMOTE|FORWARD_LOCAL)
#define FORWARD_ADM 0x100
#define FORWARD_USER 0x101
protocol handlers all get struct ssh passed; ok djm@
2017-05-30 07:23:52 -07:00
struct ssh;
more ~ support for ssh2
2000-08-19 14:55:51 -07:00
struct Channel;
typedef struct Channel Channel;
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
typedef void channel_open_fn(struct ssh *, int, int, void *);
Add channel_force_close() This will forcibly close an open channel by simulating read/write errors, draining the IO buffers and calling the detach function. Previously the detach function was only ever called during channel garbage collection, but there was no way to signal the user of a channel (e.g. session.c) that its channel was being closed deliberately (vs. by the usual state-machine logic). So this adds an extra "force" argument to the channel cleanup callback to indicate this condition. ok markus dtucker
2023-01-05 18:39:59 -08:00
typedef void channel_callback_fn(struct ssh *, int, int, void *);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
u_char **, size_t *);
support for SSH protocol 1.5 which is poorly documented, the RFC.troff lies. interops (x11,agent,etc) with 1.2.27 and protocol 1.3
1999-10-16 13:47:13 -07:00
Implement a channel success/failure status confirmation callback mechanism. Each channel maintains a queue of callbacks, which will be drained in order (RFC4253 guarantees confirm messages are not reordered within an channel). Also includes a abandonment callback to clean up if a channel is closed without sending confirmation messages. This probably shouldn't happen in compliant implementations, but it could be abused to leak memory. ok markus@ (as part of a larger diff)
2008-05-08 05:02:23 -07:00
/* Channel success/failure callbacks */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
Implement a channel success/failure status confirmation callback mechanism. Each channel maintains a queue of callbacks, which will be drained in order (RFC4253 guarantees confirm messages are not reordered within an channel). Also includes a abandonment callback to clean up if a channel is closed without sending confirmation messages. This probably shouldn't happen in compliant implementations, but it could be abused to leak memory. ok markus@ (as part of a larger diff)
2008-05-08 05:02:23 -07:00
struct channel_confirm {
TAILQ_ENTRY(channel_confirm) entry;
channel_confirm_cb *cb;
channel_confirm_abandon_cb *abandon_cb;
void *ctx;
};
TAILQ_HEAD(channel_confirms, channel_confirm);
Try additional addresses when connecting to a port forward destination whose DNS name resolves to more than one address. The previous behaviour was to try the first address and give up. Reported by stig AT venaas.com in bz#343 great feedback and ok markus@
2008-05-08 21:55:56 -07:00
/* Context for non-blocking connects */
struct channel_connect {
char *host;
int port;
struct addrinfo *ai, *aitop;
};
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
/* Callbacks for mux channels back into client-specific code */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
typedef int mux_callback_fn(struct ssh *, struct Channel *);
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
add a comment describing the ranges of channel IDs that we use; requested by markus@
2020-01-25 14:49:38 -08:00
/*
* NB. channel IDs on the wire and in c->remote_id are uint32, but local
* channel IDs (e.g. c->self) only ever use the int32 subset of this range,
* because we use local channel ID -1 for housekeeping. Remote channels have
* a dedicated "have_remote_id" flag to indicate their validity.
*/
more ~ support for ssh2
2000-08-19 14:55:51 -07:00
struct Channel {
much more KNF
1999-11-23 16:26:00 -08:00
int type; /* channel type/state */
add a comment describing the ranges of channel IDs that we use; requested by markus@
2020-01-25 14:49:38 -08:00
much more KNF
1999-11-23 16:26:00 -08:00
int self; /* my own channel identifier */
Make remote channel ID a u_int Previously we tracked the remote channel IDs in an int, but this is strictly incorrect: the wire protocol uses uint32 and there is nothing in-principle stopping a SSH implementation from sending, say, 0xffff0000. In practice everyone numbers their channels sequentially, so this has never been a problem. ok markus@
2017-09-11 23:35:31 -07:00
uint32_t remote_id; /* channel identifier for remote peer */
int have_remote_id; /* non-zero if remote_id is valid */
add chan_set_[io]state(), order states, state is now an u_int, simplifies debugging messages; ok provos@
2002-01-13 13:31:20 -08:00
u_int istate; /* input from channel (state of receive half) */
u_int ostate; /* output to channel (state of transmit half) */
channel layer support for ssh2
2000-04-03 00:07:15 -07:00
int flags; /* close sent/rcvd */
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
int rfd; /* read fd */
int wfd; /* write fd */
int efd; /* extended fd */
int sock; /* sock fd */
prepare for conversion of ssh, sshd mainloop from select() to poll() by moving FD_SET construction out of channel handlers into separate functions. ok markus
2022-01-06 13:46:23 -08:00
u_int io_want; /* bitmask of SSH_CHAN_IO_* */
u_int io_ready; /* bitmask of SSH_CHAN_IO_* */
fix poll() spin when a channel's output fd closes without data in the channel buffer. Introduce more exact packing of channel fds into the pollfd array. fixes bz3405 and bz3411; ok deraadt@ markus@
2022-03-30 14:10:25 -07:00
int pfds[4]; /* pollfd entries for rfd/wfd/efd/sock */
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
int ctl_chan; /* control channel (multiplexed connections) */
Fix proxy multiplexing (-O proxy) bug If a mux started with ControlPersist then later has a forwarding added using mux proxy connection and the forwarding was used, then when the mux proxy session terminates, the mux master process will send a channel close to the server with a bad channel ID and crash the connection. This was caused by my stupidly reusing c->remote_id for mux channel associations when I should have just added another member to struct channel. ok markus@
2024-07-25 15:40:08 -07:00
uint32_t ctl_child_id; /* child session for mux controllers */
int have_ctl_child_id;/* non-zero if ctl_child_id is valid */
genericize password padding function for SSH1 and SSH2. add stylized echo to 2, too.
2001-02-15 15:19:59 -08:00
int isatty; /* rfd is a tty */
fix some window size change bugs for multiplexed connections: windows sizes were not being updated if they had changed after ~^Z suspends and SIGWINCH was not being processed unless the first connection had requested a tty; ok markus
2004-10-29 14:47:15 -07:00
int client_tty; /* (client) TTY has been requested */
avoid possible FD_ISSET overflow for channels established during channnel_after_select() (used for dynamic channels).
2001-10-07 10:49:40 -07:00
int force_drain; /* force close on iEOF */
don't spin in accept() when out of fds (ENFILE/ENFILE) - back off for a while; ok deraadt@ markus@
2012-04-11 06:16:19 -07:00
time_t notbefore; /* Pause IO until deadline (time_t) */
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
int delayed; /* post-IO handlers for newly created
fix race condition in x11/agent channel allocation: don't read after the end of the select read/write fdset and make sure a reused FD is not touched before the pre-handlers are called. with and ok djm@
2009-11-11 13:37:03 -08:00
* channels are delayed until the first call
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
* to a matching pre-IO handler.
* this way post-IO handlers are not
typo in comment
2013-06-02 14:01:51 -07:00
* accidentally called if a FD gets reused */
restore blocking status on stdio fds before close ssh(1) needs to set file descriptors to non-blocking mode to operate but it was not restoring the original state on exit. This could cause problems with fds shared with other programs via the shell, e.g. > $ cat > test.sh << _EOF > #!/bin/sh > { > ssh -Fnone -oLogLevel=verbose ::1 hostname > cat /usr/share/dict/words > } | sleep 10 > _EOF > $ ./test.sh > Authenticated to ::1 ([::1]:22). > Transferred: sent 2352, received 2928 bytes, in 0.1 seconds > Bytes per second: sent 44338.9, received 55197.4 > cat: stdout: Resource temporarily unavailable This restores the blocking status for fds 0,1,2 (stdio) before ssh(1) abandons/closes them. This was reported as bz3280 and GHPR246; ok dtucker@
2021-05-18 18:24:05 -07:00
int restore_block; /* fd mask to restore blocking status */
when restoring non-blocking mode to stdio fds, restore exactly the flags that ssh started with and don't just clobber them with zero, as this could also remove the append flag from the set; bz3523; ok dtucker@
2023-01-17 18:00:10 -08:00
int restore_flags[3];/* flags to restore */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
struct sshbuf *input; /* data read from socket, to be sent over
much more KNF
1999-11-23 16:26:00 -08:00
* encrypted connection */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
struct sshbuf *output; /* data received over encrypted connection for
much more KNF
1999-11-23 16:26:00 -08:00
* send on socket */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
struct sshbuf *extended;
make Channel->path an allocated string, saving a few bytes here and there and fixing bz#1380 in the process; ok markus@
2009-01-22 01:46:01 -08:00
char *path;
move to Channel **channels (instead of Channel *channels), fixes realloc problems. channel_new now returns a Channel *, favour Channel * over channel id. remove old channel_allocate interface.
2001-05-04 16:47:33 -07:00
/* path for unix domain sockets, or host name for forwards */
much more KNF
1999-11-23 16:26:00 -08:00
int listening_port; /* port being listened for forwards */
support for cancelling local and remote port forwards via the multiplex socket. Use ssh -O cancel -L xx:xx:xx -R yy:yy:yy user@host" to request the cancellation of the specified forwardings; ok markus@
2011-09-09 15:46:44 -07:00
char *listening_addr; /* addr being listened for forwards */
much more KNF
1999-11-23 16:26:00 -08:00
int host_port; /* remote port to connect for forwards */
char *remote_name; /* remote hostname */
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
move channel counter to u_int
2002-06-24 07:33:27 -07:00
u_int remote_window;
u_int remote_maxpacket;
u_int local_window;
stricter handling of channel window limits This makes ssh/sshd more strict in handling non-compliant peers that send more data than the advertised channel window allows. Previously the additional data would be silently discarded. This change will cause ssh/sshd to terminate the connection if the channel window is exceeded by more than a small grace allowance. ok markus@
2023-12-18 06:47:20 -08:00
u_int local_window_exceeded;
move channel counter to u_int
2002-06-24 07:33:27 -07:00
u_int local_window_max;
u_int local_consumed;
u_int local_maxpacket;
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
int extended_usage;
setup x11 listen socket for just one connect if the client requests so. (v2 only, but the openssh client does not support this feature).
2001-12-20 08:37:29 -08:00
int single_connection;
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
Add channel_set_xtype() This sets an "extended" channel type after channel creation (e.g. "session:subsystem:sftp") that will be used for setting channel inactivity timeouts. ok markus dtucker
2023-01-05 18:42:34 -08:00
char *ctype; /* const type - NB. not freed on channel_free */
char *xctype; /* extended type */
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
use c-style comments
2000-05-02 05:44:38 -07:00
/* callback */
Pause the mux channel while waiting for reply from aynch callbacks. Prevents misordering of replies if new requests arrive while waiting. Extend channel open confirm callback to allow signalling failure conditions as well as success. Use this to 1) fix a memory leak, 2) start using the above pause mechanism and 3) delay sending a success/ failure message on mux slave session open until we receive a reply from the server. motivated by and with feedback from markus@
2010-05-14 16:29:23 -07:00
channel_open_fn *open_confirm;
Implement a channel success/failure status confirmation callback mechanism. Each channel maintains a queue of callbacks, which will be drained in order (RFC4253 guarantees confirm messages are not reordered within an channel). Also includes a abandonment callback to clean up if a channel is closed without sending confirmation messages. This probably shouldn't happen in compliant implementations, but it could be abused to leak memory. ok markus@ (as part of a larger diff)
2008-05-08 05:02:23 -07:00
void *open_confirm_ctx;
fix regression I introduced in 4.2: X11 forwardings initiated after a session has exited (e.g. "(sleep 5; xterm) &") would not start. bz #1086 reported by t8m AT centrum.cz; ok markus@ dtucker@
2005-10-10 03:23:08 -07:00
channel_callback_fn *detach_user;
int detach_close;
Implement a channel success/failure status confirmation callback mechanism. Each channel maintains a queue of callbacks, which will be drained in order (RFC4253 guarantees confirm messages are not reordered within an channel). Also includes a abandonment callback to clean up if a channel is closed without sending confirmation messages. This probably shouldn't happen in compliant implementations, but it could be abused to leak memory. ok markus@ (as part of a larger diff)
2008-05-08 05:02:23 -07:00
struct channel_confirms status_confirms;
support for ~. in ssh2
2000-08-19 11:48:10 -07:00
/* filter */
add channel output filter interface. ok djm@, suggested by markus@
2005-12-30 07:56:36 -08:00
channel_infilter_fn *input_filter;
channel_outfilter_fn *output_filter;
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@
2008-06-11 20:40:52 -07:00
void *filter_ctx;
The multiplexing escape char handler commit last night introduced a small memory leak per session; plug it.
2008-06-12 08:19:17 -07:00
channel_filter_cleanup_fn *filter_cleanup;
Add support for tun(4) forwarding over OpenSSH, based on an idea and initial channel code bits by markus@. This is a simple and easy way to use OpenSSH for ad hoc virtual private network connections, e.g. administrative tunnels or secure wireless access. It's based on a new ssh channel and works similar to the existing TCP forwarding support, except that it depends on the tun(4) network interface on both ends of the connection for layer 2 or layer 3 tunneling. This diff also adds support for LocalCommand in the ssh(1) client. ok djm@, markus@, jmc@ (manpages), tested and discussed with others
2005-12-06 14:38:27 -08:00
Try additional addresses when connecting to a port forward destination whose DNS name resolves to more than one address. The previous behaviour was to try the first address and give up. Reported by stig AT venaas.com in bz#343 great feedback and ok markus@
2008-05-08 21:55:56 -07:00
/* keep boundaries */
whitespace (tab after space)
2021-04-02 22:54:14 -07:00
int datagram;
Try additional addresses when connecting to a port forward destination whose DNS name resolves to more than one address. The previous behaviour was to try the first address and give up. Reported by stig AT venaas.com in bz#343 great feedback and ok markus@
2008-05-08 21:55:56 -07:00
/* non-blocking connect */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
/* XXX make this a pointer so the structure can be opaque */
Try additional addresses when connecting to a port forward destination whose DNS name resolves to more than one address. The previous behaviour was to try the first address and give up. Reported by stig AT venaas.com in bz#343 great feedback and ok markus@
2008-05-08 21:55:56 -07:00
struct channel_connect connect_ctx;
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
/* multiplexing protocol hook, called for each packet received */
mux_callback_fn *mux_rcb;
void *mux_ctx;
Pause the mux channel while waiting for reply from aynch callbacks. Prevents misordering of replies if new requests arrive while waiting. Extend channel open confirm callback to allow signalling failure conditions as well as success. Use this to 1) fix a memory leak, 2) start using the above pause mechanism and 3) delay sending a success/ failure message on mux slave session open until we receive a reply from the server. motivated by and with feedback from markus@
2010-05-14 16:29:23 -07:00
int mux_pause;
whitespace (tab after space)
2021-04-02 22:54:14 -07:00
int mux_downstream_id;
Implement channel inactivity timeouts This adds a sshd_config ChannelTimeouts directive that allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. Note: this only affects channels over an opened SSH connection and not the connection itself. Most clients close the connection when their channels go away, with a notable exception being ssh(1) in multiplexing mode. ok markus dtucker
2023-01-05 18:47:18 -08:00
/* Inactivity timeouts */
/* Last traffic seen for OPEN channels */
time_t lastused;
/* Inactivity timeout deadline in seconds (0 = no timeout) */
Store timeouts as int, not u_int as they are limited to INT_MAX. Fixes sign compare warnings systems with 32-bit time_t due to type promotion. OK djm@
2023-06-05 06:24:36 -07:00
int inactive_deadline;
more ~ support for ssh2
2000-08-19 14:55:51 -07:00
};
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
#define CHAN_EXTENDED_IGNORE 0
#define CHAN_EXTENDED_READ 1
#define CHAN_EXTENDED_WRITE 2
cleanup window and packet sizes for ssh2 flow control; ok niels
2000-09-07 13:40:29 -07:00
/* default window/packet sizes for tcp/x11-fwd-channel */
increase the SSH v2 window size to 4 packets. comsumes a little bit more memory for slow receivers but increases througput.
2002-02-14 15:27:59 -08:00
#define CHAN_SES_PACKET_DEFAULT (32*1024)
increase default channel windows; ok djm
2007-06-11 02:14:00 -07:00
#define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
increase the SSH v2 window size to 4 packets. comsumes a little bit more memory for slow receivers but increases througput.
2002-02-14 15:27:59 -08:00
#define CHAN_TCP_PACKET_DEFAULT (32*1024)
increase default channel windows; ok djm
2007-06-11 02:14:00 -07:00
#define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
increase the SSH v2 window size to 4 packets. comsumes a little bit more memory for slow receivers but increases througput.
2002-02-14 15:27:59 -08:00
#define CHAN_X11_PACKET_DEFAULT (16*1024)
#define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
cleanup window and packet sizes for ssh2 flow control; ok niels
2000-09-07 13:40:29 -07:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* possible input states */
add chan_set_[io]state(), order states, state is now an u_int, simplifies debugging messages; ok provos@
2002-01-13 13:31:20 -08:00
#define CHAN_INPUT_OPEN 0
#define CHAN_INPUT_WAIT_DRAIN 1
#define CHAN_INPUT_WAIT_OCLOSE 2
#define CHAN_INPUT_CLOSED 3
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* possible output states */
add chan_set_[io]state(), order states, state is now an u_int, simplifies debugging messages; ok provos@
2002-01-13 13:31:20 -08:00
#define CHAN_OUTPUT_OPEN 0
#define CHAN_OUTPUT_WAIT_DRAIN 1
#define CHAN_OUTPUT_WAIT_IEOF 2
#define CHAN_OUTPUT_CLOSED 3
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
#define CHAN_CLOSE_SENT 0x01
#define CHAN_CLOSE_RCVD 0x02
don't send stderr data after EOF, accept this from older known (broken) sshd servers only, fixes http://bugzilla.mindrot.org/show_bug.cgi?id=179
2002-03-25 13:13:51 -08:00
#define CHAN_EOF_SENT 0x04
#define CHAN_EOF_RCVD 0x08
rewrite ssh(1) multiplexing code to a more sensible protocol. The new multiplexing code uses channels for the listener and accepted control sockets to make the mux master non-blocking, so no stalls when processing messages from a slave. avoid use of fatal() in mux master protocol parsing so an errant slave process cannot take down a running master. implement requesting of port-forwards over multiplexed sessions. Any port forwards requested by the slave are added to those the master has established. add support for stdio forwarding ("ssh -W host:port ...") in mux slaves. document master/slave mux protocol so that other tools can use it to control a running ssh(1). Note: there are no guarantees that this protocol won't be incompatibly changed (though it is versioned). feedback Salvador Fandino, dtucker@ channel changes ok markus@
2010-01-25 17:28:35 -08:00
#define CHAN_LOCAL 0x10
don't send stderr data after EOF, accept this from older known (broken) sshd servers only, fixes http://bugzilla.mindrot.org/show_bug.cgi?id=179
2002-03-25 13:13:51 -08:00
prepare for conversion of ssh, sshd mainloop from select() to poll() by moving FD_SET construction out of channel handlers into separate functions. ok markus
2022-01-06 13:46:23 -08:00
/* file descriptor events */
#define SSH_CHAN_IO_RFD 0x01
#define SSH_CHAN_IO_WFD 0x02
#define SSH_CHAN_IO_EFD_R 0x04
#define SSH_CHAN_IO_EFD_W 0x08
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
#define SSH_CHAN_IO_EFD (SSH_CHAN_IO_EFD_R|SSH_CHAN_IO_EFD_W)
prepare for conversion of ssh, sshd mainloop from select() to poll() by moving FD_SET construction out of channel handlers into separate functions. ok markus
2022-01-06 13:46:23 -08:00
#define SSH_CHAN_IO_SOCK_R 0x10
#define SSH_CHAN_IO_SOCK_W 0x20
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
#define SSH_CHAN_IO_SOCK (SSH_CHAN_IO_SOCK_R|SSH_CHAN_IO_SOCK_W)
prepare for conversion of ssh, sshd mainloop from select() to poll() by moving FD_SET construction out of channel handlers into separate functions. ok markus
2022-01-06 13:46:23 -08:00
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
/* Read buffer size */
#define CHAN_RBUF (16*1024)
add a ssh_packet_process_read() function that reads from a fd directly into the transport input buffer. Use this in the client and server mainloops to avoid unnecessary copying. It also lets us use a more greedy read size without penalty. Yields a 2-3% performance gain on cipher-speed.sh (in a fairly unscientific test tbf) feedback dtucker@ ok markus@
2022-01-21 16:49:34 -08:00
/* Maximum size for direct reads to buffers */
#define CHANNEL_MAX_READ CHAN_SES_PACKET_DEFAULT
cap channel input buffer size at 16MB; avoids high memory use when peer advertises a large window but is slow to consume the data we send (e.g. because of a slow network) reported by Pierre-Yves David fix with & ok markus@
2020-09-19 22:47:25 -07:00
/* Maximum channel input buffer size */
#define CHAN_INPUT_MAX (16*1024*1024)
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
/* Hard limit on number of channels */
#define CHANNELS_MAX_CHANNELS (16*1024)
add channel output filter interface. ok djm@, suggested by markus@
2005-12-30 07:56:36 -08:00
don't send stderr data after EOF, accept this from older known (broken) sshd servers only, fixes http://bugzilla.mindrot.org/show_bug.cgi?id=179
2002-03-25 13:13:51 -08:00
/* check whether 'efd' is still in use */
#define CHANNEL_EFD_INPUT_ACTIVE(c) \
remove compat20/compat13/compat15 variables ok markus@
2017-04-30 16:13:25 -07:00
(c->extended_usage == CHAN_EXTENDED_READ && \
don't send stderr data after EOF, accept this from older known (broken) sshd servers only, fixes http://bugzilla.mindrot.org/show_bug.cgi?id=179
2002-03-25 13:13:51 -08:00
(c->efd != -1 || \
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
sshbuf_len(c->extended) > 0))
don't send stderr data after EOF, accept this from older known (broken) sshd servers only, fixes http://bugzilla.mindrot.org/show_bug.cgi?id=179
2002-03-25 13:13:51 -08:00
#define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
remove compat20/compat13/compat15 variables ok markus@
2017-04-30 16:13:25 -07:00
(c->extended_usage == CHAN_EXTENDED_WRITE && \
race when efd gets closed while there is still buffered data: change CHANNEL_EFD_OUTPUT_ACTIVE() 1) c->efd must always be valid AND 2a) no EOF has been seen OR 2b) there is buffered data report, initial fix and testing Chuck Cranor
2005-07-08 02:41:33 -07:00
c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
sshbuf_len(c->extended) > 0))
/* Add channel management structures to SSH transport instance */
void channel_init_channels(struct ssh *ssh);
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* channel management */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
Channel *channel_by_id(struct ssh *, int);
Make remote channel ID a u_int Previously we tracked the remote channel IDs in an int, but this is strictly incorrect: the wire protocol uses uint32 and there is nothing in-principle stopping a SSH implementation from sending, say, 0xffff0000. In practice everyone numbers their channels sequentially, so this has never been a problem. ok markus@
2017-09-11 23:35:31 -07:00
Channel *channel_by_remote_id(struct ssh *, u_int);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
Channel *channel_lookup(struct ssh *, int);
Channel *channel_new(struct ssh *, char *, int, int, int, int,
channel_new no longer frees remote_name. So update the comment accordingly. As remote_name is not modified, it can be const as well. From Martin Vahlensieck
2022-05-04 17:56:58 -07:00
u_int, u_int, int, const char *, int);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
void channel_set_fds(struct ssh *, int, int, int, int, int,
int, int, u_int);
void channel_free(struct ssh *, Channel *);
void channel_free_all(struct ssh *);
void channel_stop_listening(struct ssh *);
Add channel_force_close() This will forcibly close an open channel by simulating read/write errors, draining the IO buffers and calling the detach function. Previously the detach function was only ever called during channel garbage collection, but there was no way to signal the user of a channel (e.g. session.c) that its channel was being closed deliberately (vs. by the usual state-machine logic). So this adds an extra "force" argument to the channel cleanup callback to indicate this condition. ok markus dtucker
2023-01-05 18:39:59 -08:00
void channel_force_close(struct ssh *, Channel *, int);
Add channel_set_xtype() This sets an "extended" channel type after channel creation (e.g. "session:subsystem:sftp") that will be used for setting channel inactivity timeouts. ok markus dtucker
2023-01-05 18:42:34 -08:00
void channel_set_xtype(struct ssh *, int, const char *);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
void channel_send_open(struct ssh *, int);
void channel_request_start(struct ssh *, int, char *, int);
void channel_register_cleanup(struct ssh *, int,
channel_callback_fn *, int);
void channel_register_open_confirm(struct ssh *, int,
channel_open_fn *, void *);
void channel_register_filter(struct ssh *, int, channel_infilter_fn *,
channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
void channel_register_status_confirm(struct ssh *, int,
channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
void channel_cancel_cleanup(struct ssh *, int);
restore blocking status on stdio fds before close ssh(1) needs to set file descriptors to non-blocking mode to operate but it was not restoring the original state on exit. This could cause problems with fds shared with other programs via the shell, e.g. > $ cat > test.sh << _EOF > #!/bin/sh > { > ssh -Fnone -oLogLevel=verbose ::1 hostname > cat /usr/share/dict/words > } | sleep 10 > _EOF > $ ./test.sh > Authenticated to ::1 ([::1]:22). > Transferred: sent 2352, received 2928 bytes, in 0.1 seconds > Bytes per second: sent 44338.9, received 55197.4 > cat: stdout: Resource temporarily unavailable This restores the blocking status for fds 0,1,2 (stdio) before ssh(1) abandons/closes them. This was reported as bz3280 and GHPR246; ok dtucker@
2021-05-18 18:24:05 -07:00
int channel_close_fd(struct ssh *, Channel *, int *);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
void channel_send_window_changes(struct ssh *);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
Implement channel inactivity timeouts This adds a sshd_config ChannelTimeouts directive that allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. Note: this only affects channels over an opened SSH connection and not the connection itself. Most clients close the connection when their channels go away, with a notable exception being ssh(1) in multiplexing mode. ok markus dtucker
2023-01-05 18:47:18 -08:00
/* channel inactivity timeouts */
Store timeouts as int, not u_int as they are limited to INT_MAX. Fixes sign compare warnings systems with 32-bit time_t due to type promotion. OK djm@
2023-06-05 06:24:36 -07:00
void channel_add_timeout(struct ssh *, const char *, int);
Implement channel inactivity timeouts This adds a sshd_config ChannelTimeouts directive that allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. Note: this only affects channels over an opened SSH connection and not the connection itself. Most clients close the connection when their channels go away, with a notable exception being ssh(1) in multiplexing mode. ok markus dtucker
2023-01-05 18:47:18 -08:00
void channel_clear_timeouts(struct ssh *);
ssh proxy mux mode (-O proxy; idea from Simon Tatham): - mux client speaks the ssh-packet protocol directly over unix-domain socket. - mux server acts as a proxy, translates channel IDs and relays to the server. - no filedescriptor passing necessary. - combined with unix-domain forwarding it's even possible to run mux client and server on different machines. feedback & ok djm@
2016-09-30 02:19:13 -07:00
/* mux proxy support */
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
int channel_proxy_downstream(struct ssh *, Channel *mc);
protocol handlers all get struct ssh passed; ok djm@
2017-05-30 07:23:52 -07:00
int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
ssh proxy mux mode (-O proxy; idea from Simon Tatham): - mux client speaks the ssh-packet protocol directly over unix-domain socket. - mux server acts as a proxy, translates channel IDs and relays to the server. - no filedescriptor passing necessary. - combined with unix-domain forwarding it's even possible to run mux client and server on different machines. feedback & ok djm@
2016-09-30 02:19:13 -07:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* protocol handler */
deny agent/x11 forwarding unless requested; thanks to jwl@pobox.com
2000-10-27 00:48:22 -07:00
protocol handlers all get struct ssh passed; ok djm@
2017-05-30 07:23:52 -07:00
int channel_input_data(int, u_int32_t, struct ssh *);
int channel_input_extended_data(int, u_int32_t, struct ssh *);
int channel_input_ieof(int, u_int32_t, struct ssh *);
int channel_input_oclose(int, u_int32_t, struct ssh *);
int channel_input_open_confirmation(int, u_int32_t, struct ssh *);
int channel_input_open_failure(int, u_int32_t, struct ssh *);
int channel_input_window_adjust(int, u_int32_t, struct ssh *);
int channel_input_status_confirm(int, u_int32_t, struct ssh *);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* file descriptor handling (read/write) */
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
struct pollfd;
replace manual poll/ppoll timeout math with ptimeout API feedback markus / ok markus dtucker
2023-01-05 18:38:23 -08:00
struct timespec;
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
void channel_prepare_poll(struct ssh *, struct pollfd **,
replace manual poll/ppoll timeout math with ptimeout API feedback markus / ok markus dtucker
2023-01-05 18:38:23 -08:00
u_int *, u_int *, u_int, struct timespec *);
convert ssh, sshd mainloops from select() to poll(); feedback & ok deraadt@ and markus@ has been in snaps for a few months
2022-01-06 13:48:38 -08:00
void channel_after_poll(struct ssh *, struct pollfd *, u_int);
make channel_output_poll() return a flag indicating whether channel data was enqueued. Will be used to improve keystroke timing obfuscation. Problem spotted by / tested by naddy@
2023-09-03 17:01:46 -07:00
int channel_output_poll(struct ssh *);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
int channel_not_very_much_buffered_data(struct ssh *);
void channel_close_all(struct ssh *);
int channel_still_open(struct ssh *);
when deciding whether to enable keystroke timing obfuscation, only consider enabling it when a channel with a tty is open. Avoids turning on the obfucation when X11 forwarding only is in use, which slows it right down. Reported by Roger Marsh
2023-11-15 14:51:49 -08:00
int channel_tty_open(struct ssh *);
include a little more information about the status and disposition of channel's extended (stderr) fd; makes debugging some things a bit easier. No behaviour change.
2018-10-03 17:10:11 -07:00
const char *channel_format_extended_usage(const Channel *);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
char *channel_open_message(struct ssh *);
int channel_find_open(struct ssh *);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
remove ugliness; vp@drexel.edu via angelos
2001-10-01 14:38:53 -07:00
/* tcp forwarding */
Add support for Unix domain socket forwarding. A remote TCP port may be forwarded to a local Unix domain socket and vice versa or both ends may be a Unix domain socket. This is a reimplementation of the streamlocal patches by William Ahern from: http://www.25thandclement.com/~william/projects/streamlocal.html OK djm@ markus@
2014-07-15 08:54:14 -07:00
struct Forward;
struct ForwardOptions;
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
void channel_set_af(struct ssh *, int af);
Add a PermitListen directive to control which server-side addresses may be listened on when the client requests remote forwarding (ssh -R). This is the converse of the existing PermitOpen directive and this includes some refactoring to share much of its implementation. feedback and ok markus@
2018-06-06 11:22:41 -07:00
void channel_permit_all(struct ssh *, int);
void channel_add_permission(struct ssh *, int, int, char *, int);
void channel_clear_permission(struct ssh *, int, int);
void channel_disable_admin(struct ssh *, int);
void channel_update_permission(struct ssh *, int, int);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
Channel *channel_connect_to_port(struct ssh *, const char *, u_short,
char *, char *, int *, const char **);
Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
Channel *channel_connect_stdio_fwd(struct ssh *, const char*,
add support for unix domain sockets to ssh -W ok djm@ dtucker@
2023-07-03 20:59:21 -07:00
int, int, int, int);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
Channel *channel_connect_by_listen_address(struct ssh *, const char *,
u_short, char *, char *);
Channel *channel_connect_by_listen_path(struct ssh *, const char *,
char *, char *);
int channel_request_remote_forwarding(struct ssh *, struct Forward *);
int channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
struct ForwardOptions *);
int channel_request_rforward_cancel(struct ssh *, struct Forward *);
int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
int *, struct ForwardOptions *);
int channel_cancel_rport_listener(struct ssh *, struct Forward *);
int channel_cancel_lport_listener(struct ssh *, struct Forward *,
int, struct ForwardOptions *);
Add wildcard support to PermitOpen, allowing things like "PermitOpen localhost:*". bz #1857, ok djm markus.
2011-09-22 17:22:04 -07:00
int permitopen_port(const char *);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* x11 forwarding */
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
Use time_t instead of u_int for remaining x11 timeout checks for 64bit time_t safety. From Coverity CIDs 405197 and 405028, ok djm@
2023-03-03 19:22:59 -08:00
void channel_set_x11_refuse_time(struct ssh *, time_t);
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
int x11_connect_display(struct ssh *);
int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
void x11_request_forwarding_with_spoofing(struct ssh *, int,
const char *, const char *, const char *, int);
don't start the ObscureKeystrokeTiming mitigations if there has been traffic on a X11 forwarding channel recently. Should fix X11 forwarding performance problems when this setting is enabled. Patch from Antonio Larrosa via bz3655
2024-10-13 15:20:06 -07:00
int x11_channel_used_recently(struct ssh *ssh);
replace big switch() with function tables (prepare for ssh2)
2000-03-28 12:31:25 -08:00
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
/* channel close */
channel layer support for ssh2
2000-04-03 00:07:15 -07:00
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
int chan_is_dead(struct ssh *, Channel *, int);
void chan_mark_dead(struct ssh *, Channel *);
remove comments from .h, since they are cut&paste from the .c files and out of sync
2001-06-26 10:27:22 -07:00
remove function pointers for events, remove chan_init*; ok provos@
2002-01-14 05:55:55 -08:00
/* channel events */
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
refactor channels.c Move static state to a "struct ssh_channels" that is allocated at runtime and tracked as a member of struct ssh. Explicitly pass "struct ssh" to all channels functions. Replace use of the legacy packet APIs in channels.c. Rework sshd_config PermitOpen handling: previously the configuration parser would call directly into the channels layer. After the refactor this is not possible, as the channels structures are allocated at connection time and aren't available when the configuration is parsed. The server config parser now tracks PermitOpen itself and explicitly configures the channels code later. ok markus@
2017-09-11 23:32:07 -07:00
void chan_rcvd_oclose(struct ssh *, Channel *);
void chan_rcvd_eow(struct ssh *, Channel *);
void chan_read_failed(struct ssh *, Channel *);
void chan_ibuf_empty(struct ssh *, Channel *);
void chan_rcvd_ieof(struct ssh *, Channel *);
void chan_write_failed(struct ssh *, Channel *);
void chan_obuf_empty(struct ssh *, Channel *);
channel layer cleanup: merge header files and split .c files
2001-05-30 05:55:06 -07:00
support for SSH protocol 1.5 which is poorly documented, the RFC.troff lies. interops (x11,agent,etc) with 1.2.27 and protocol 1.3
1999-10-16 13:47:13 -07:00
#endif
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