ports/libssh
ports/libssh
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libssh/src/channels.c
Aris Adamantiadis 6d8bb956c5 channels: replaced bugged lists with ssh_list 
cherry-picked from 0aef5f
Conflicts:

	src/session.c
2011-09-02 13:46:10 +03:00

3338 строки
86 KiB
C
Исходник Ответственный История

/*
* channels.c - SSH channel functions
*
* This file is part of the SSH Library
*
* Copyright (c) 2003-2008 by Aris Adamantiadis
* Copyright (c) 2009 by Andreas Schneider <mail@cynapses.org>
*
* The SSH Library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The SSH Library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the SSH Library; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#include <limits.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <time.h>
#ifndef _WIN32
#include <arpa/inet.h>
#endif
#include "libssh/priv.h"
#include "libssh/ssh2.h"
#include "libssh/buffer.h"
#include "libssh/packet.h"
#include "libssh/socket.h"
#include "libssh/channels.h"
#include "libssh/session.h"
#include "libssh/misc.h"
#include "libssh/messages.h"
#if WITH_SERVER
#include "libssh/server.h"
#endif
#define WINDOWBASE 1280000
#define WINDOWLIMIT (WINDOWBASE/2)
/*
* All implementations MUST be able to process packets with an
* uncompressed payload length of 32768 bytes or less and a total packet
* size of 35000 bytes or less.
*/
#define CHANNEL_MAX_PACKET 32768
#define CHANNEL_INITIAL_WINDOW 64000
/**
* @defgroup libssh_channel The SSH channel functions
* @ingroup libssh
*
* Functions that manage a SSH channel.
*
* @{
*/
static ssh_channel channel_from_msg(ssh_session session, ssh_buffer packet);
/**
* @brief Allocate a new channel.
*
* @param[in] session The ssh session to use.
*
* @return A pointer to a newly allocated channel, NULL on error.
*/
ssh_channel ssh_channel_new(ssh_session session) {
ssh_channel channel = NULL;
if(session == NULL) {
return NULL;
}
channel = malloc(sizeof(struct ssh_channel_struct));
if (channel == NULL) {
ssh_set_error_oom(session);
return NULL;
}
memset(channel,0,sizeof(struct ssh_channel_struct));
channel->stdout_buffer = ssh_buffer_new();
if (channel->stdout_buffer == NULL) {
ssh_set_error_oom(session);
SAFE_FREE(channel);
return NULL;
}
channel->stderr_buffer = ssh_buffer_new();
if (channel->stderr_buffer == NULL) {
ssh_set_error_oom(session);
ssh_buffer_free(channel->stdout_buffer);
SAFE_FREE(channel);
return NULL;
}
channel->session = session;
channel->version = session->version;
channel->exit_status = -1;
if(session->channels == NULL) {
session->channels = ssh_list_new();
}
ssh_list_prepend(session->channels, channel);
return channel;
}
/**
* @internal
*
* @brief Create a new channel identifier.
*
* @param[in] session The SSH session to use.
*
* @return The new channel identifier.
*/
uint32_t ssh_channel_new_id(ssh_session session) {
return ++(session->maxchannel);
}
/**
* @internal
*
* @brief Handle a SSH_PACKET_CHANNEL_OPEN_CONFIRMATION packet.
*
* Constructs the channel object.
*/
SSH_PACKET_CALLBACK(ssh_packet_channel_open_conf){
uint32_t channelid=0;
uint32_t tmp;
ssh_channel channel;
(void)type;
(void)user;
enter_function();
ssh_log(session,SSH_LOG_PACKET,"Received SSH2_MSG_CHANNEL_OPEN_CONFIRMATION");
buffer_get_u32(packet, &channelid);
channelid=ntohl(channelid);
channel=ssh_channel_from_local(session,channelid);
if(channel==NULL){
ssh_set_error(session, SSH_FATAL,
"Unknown channel id %lu",
(long unsigned int) channelid);
/* TODO: Set error marking in channel object */
leave_function();
return SSH_PACKET_USED;
}
buffer_get_u32(packet, &tmp);
channel->remote_channel = ntohl(tmp);
buffer_get_u32(packet, &tmp);
channel->remote_window = ntohl(tmp);
buffer_get_u32(packet,&tmp);
channel->remote_maxpacket=ntohl(tmp);
ssh_log(session, SSH_LOG_PROTOCOL,
"Received a CHANNEL_OPEN_CONFIRMATION for channel %d:%d",
channel->local_channel,
channel->remote_channel);
ssh_log(session, SSH_LOG_PROTOCOL,
"Remote window : %lu, maxpacket : %lu",
(long unsigned int) channel->remote_window,
(long unsigned int) channel->remote_maxpacket);
channel->state = SSH_CHANNEL_STATE_OPEN;
leave_function();
return SSH_PACKET_USED;
}
/**
* @internal
*
* @brief Handle a SSH_CHANNEL_OPEN_FAILURE and set the state of the channel.
*/
SSH_PACKET_CALLBACK(ssh_packet_channel_open_fail){
ssh_channel channel;
ssh_string error_s;
char *error = NULL;
uint32_t code;
(void)user;
(void)type;
channel=channel_from_msg(session,packet);
if(channel==NULL){
ssh_log(session,SSH_LOG_RARE,"Invalid channel in packet");
return SSH_PACKET_USED;
}
buffer_get_u32(packet, &code);
error_s = buffer_get_ssh_string(packet);
if(error_s != NULL)
error = ssh_string_to_char(error_s);
ssh_string_free(error_s);
if (error == NULL) {
ssh_set_error_oom(session);
return SSH_PACKET_USED;
}
ssh_set_error(session, SSH_REQUEST_DENIED,
"Channel opening failure: channel %u error (%lu) %s",
channel->local_channel,
(long unsigned int) ntohl(code),
error);
SAFE_FREE(error);
channel->state=SSH_CHANNEL_STATE_OPEN_DENIED;
return SSH_PACKET_USED;
}
/**
* @internal
*
* @brief Open a channel by sending a SSH_OPEN_CHANNEL message and
* wait for the reply.
*
* @param[in] channel The current channel.
*
* @param[in] type_c A C string describing the kind of channel (e.g. "exec").
*
* @param[in] window The receiving window of the channel. The window is the
* maximum size of data that can stay in buffers and
* network.
*
* @param[in] maxpacket The maximum packet size allowed (like MTU).
*
* @param[in] payload The buffer containing additional payload for the query.
*/
static int channel_open(ssh_channel channel, const char *type_c, int window,
int maxpacket, ssh_buffer payload) {
ssh_session session = channel->session;
ssh_string type = NULL;
int timeout;
int err=SSH_ERROR;
enter_function();
switch(channel->state){
case SSH_CHANNEL_STATE_NOT_OPEN:
break;
case SSH_CHANNEL_STATE_OPENING:
goto pending;
case SSH_CHANNEL_STATE_OPEN:
case SSH_CHANNEL_STATE_CLOSED:
case SSH_CHANNEL_STATE_OPEN_DENIED:
goto end;
default:
ssh_set_error(session,SSH_FATAL,"Bad state in channel_open: %d",channel->state);
}
channel->local_channel = ssh_channel_new_id(session);
channel->local_maxpacket = maxpacket;
channel->local_window = window;
ssh_log(session, SSH_LOG_PROTOCOL,
"Creating a channel %d with %d window and %d max packet",
channel->local_channel, window, maxpacket);
type = ssh_string_from_char(type_c);
if (type == NULL) {
ssh_set_error_oom(session);
leave_function();
return err;
}
if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_OPEN) < 0 ||
buffer_add_ssh_string(session->out_buffer,type) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->local_channel)) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->local_window)) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->local_maxpacket)) < 0) {
ssh_set_error_oom(session);
ssh_string_free(type);
leave_function();
return err;
}
ssh_string_free(type);
if (payload != NULL) {
if (buffer_add_buffer(session->out_buffer, payload) < 0) {
ssh_set_error_oom(session);
leave_function();
return err;
}
}
channel->state = SSH_CHANNEL_STATE_OPENING;
if (packet_send(session) == SSH_ERROR) {
leave_function();
return err;
}
ssh_log(session, SSH_LOG_PACKET,
"Sent a SSH_MSG_CHANNEL_OPEN type %s for channel %d",
type_c, channel->local_channel);
pending:
/* wait until channel is opened by server */
if(ssh_is_blocking(session))
timeout=-2;
else
timeout=0;
while(channel->state == SSH_CHANNEL_STATE_OPENING){
err = ssh_handle_packets(session, timeout);
if (err != SSH_OK) {
break;
}
if (session->session_state == SSH_SESSION_STATE_ERROR) {
err = SSH_ERROR;
break;
}
}
end:
if(channel->state == SSH_CHANNEL_STATE_OPEN)
err=SSH_OK;
leave_function();
return err;
}
/* return channel with corresponding local id, or NULL if not found */
ssh_channel ssh_channel_from_local(ssh_session session, uint32_t id) {
struct ssh_iterator *it;
ssh_channel channel;
for (it = ssh_list_get_iterator(session->channels); it != NULL ; it=it->next) {
channel = ssh_iterator_value(ssh_channel, it);
if (channel == NULL) {
continue;
}
if (channel->local_channel == id) {
return channel;
}
}
return NULL;
}
/**
* @internal
* @brief grows the local window and send a packet to the other party
* @param session SSH session
* @param channel SSH channel
* @param minimumsize The minimum acceptable size for the new window.
*/
static int grow_window(ssh_session session, ssh_channel channel, int minimumsize) {
uint32_t new_window = minimumsize > WINDOWBASE ? minimumsize : WINDOWBASE;
enter_function();
if(new_window <= channel->local_window){
ssh_log(session,SSH_LOG_PROTOCOL,
"growing window (channel %d:%d) to %d bytes : not needed (%d bytes)",
channel->local_channel, channel->remote_channel, new_window,
channel->local_window);
leave_function();
return SSH_OK;
}
/* WINDOW_ADJUST packet needs a relative increment rather than an absolute
* value, so we give here the missing bytes needed to reach new_window
*/
if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_WINDOW_ADJUST) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->remote_channel)) < 0 ||
buffer_add_u32(session->out_buffer, htonl(new_window - channel->local_window)) < 0) {
ssh_set_error_oom(session);
goto error;
}
if (packet_send(session) == SSH_ERROR) {
goto error;
}
ssh_log(session, SSH_LOG_PROTOCOL,
"growing window (channel %d:%d) to %d bytes",
channel->local_channel,
channel->remote_channel,
new_window);
channel->local_window = new_window;
leave_function();
return SSH_OK;
error:
buffer_reinit(session->out_buffer);
leave_function();
return SSH_ERROR;
}
/**
* @internal
*
* @brief Parse a channel-related packet to resolve it to a ssh_channel.
*
* This works on SSH1 sessions too.
*
* @param[in] session The current SSH session.
*
* @param[in] packet The buffer to parse packet from. The read pointer will
* be moved after the call.
*
* @returns The related ssh_channel, or NULL if the channel is
* unknown or the packet is invalid.
*/
static ssh_channel channel_from_msg(ssh_session session, ssh_buffer packet) {
ssh_channel channel;
uint32_t chan;
#ifdef WITH_SSH1
/* With SSH1, the channel is always the first one */
if(session->version==1)
return ssh_get_channel1(session);
#endif
if (buffer_get_u32(packet, &chan) != sizeof(uint32_t)) {
ssh_set_error(session, SSH_FATAL,
"Getting channel from message: short read");
return NULL;
}
channel = ssh_channel_from_local(session, ntohl(chan));
if (channel == NULL) {
ssh_set_error(session, SSH_FATAL,
"Server specified invalid channel %lu",
(long unsigned int) ntohl(chan));
}
return channel;
}
SSH_PACKET_CALLBACK(channel_rcv_change_window) {
ssh_channel channel;
uint32_t bytes;
int rc;
(void)user;
(void)type;
enter_function();
channel = channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS, "%s", ssh_get_error(session));
}
rc = buffer_get_u32(packet, &bytes);
if (channel == NULL || rc != sizeof(uint32_t)) {
ssh_log(session, SSH_LOG_PACKET,
"Error getting a window adjust message: invalid packet");
leave_function();
return SSH_PACKET_USED;
}
bytes = ntohl(bytes);
ssh_log(session, SSH_LOG_PROTOCOL,
"Adding %d bytes to channel (%d:%d) (from %d bytes)",
bytes,
channel->local_channel,
channel->remote_channel,
channel->remote_window);
channel->remote_window += bytes;
leave_function();
return SSH_PACKET_USED;
}
/* is_stderr is set to 1 if the data are extended, ie stderr */
SSH_PACKET_CALLBACK(channel_rcv_data){
ssh_channel channel;
ssh_string str;
ssh_buffer buf;
size_t len;
int is_stderr;
int rest;
(void)user;
enter_function();
if(type==SSH2_MSG_CHANNEL_DATA)
is_stderr=0;
else
is_stderr=1;
channel = channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS,
"%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
if (is_stderr) {
uint32_t ignore;
/* uint32 data type code. we can ignore it */
buffer_get_u32(packet, &ignore);
}
str = buffer_get_ssh_string(packet);
if (str == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid data packet!");
leave_function();
return SSH_PACKET_USED;
}
len = ssh_string_len(str);
ssh_log(session, SSH_LOG_PROTOCOL,
"Channel receiving %" PRIdS " bytes data in %d (local win=%d remote win=%d)",
len,
is_stderr,
channel->local_window,
channel->remote_window);
/* What shall we do in this case? Let's accept it anyway */
if (len > channel->local_window) {
ssh_log(session, SSH_LOG_RARE,
"Data packet too big for our window(%" PRIdS " vs %d)",
len,
channel->local_window);
}
if (channel_default_bufferize(channel, ssh_string_data(str), len,
is_stderr) < 0) {
ssh_string_free(str);
leave_function();
return SSH_PACKET_USED;
}
if (len <= channel->local_window) {
channel->local_window -= len;
} else {
channel->local_window = 0; /* buggy remote */
}
ssh_log(session, SSH_LOG_PROTOCOL,
"Channel windows are now (local win=%d remote win=%d)",
channel->local_window,
channel->remote_window);
ssh_string_free(str);
if(ssh_callbacks_exists(channel->callbacks, channel_data_function)) {
if(is_stderr) {
buf = channel->stderr_buffer;
} else {
buf = channel->stdout_buffer;
}
rest = channel->callbacks->channel_data_function(channel->session,
channel,
buffer_get_rest(buf),
buffer_get_rest_len(buf),
is_stderr,
channel->callbacks->userdata);
if(rest > 0) {
buffer_pass_bytes(buf, rest);
}
if (channel->local_window + buffer_get_rest_len(buf) < WINDOWLIMIT) {
if (grow_window(session, channel, 0) < 0) {
leave_function();
return -1;
}
}
}
leave_function();
return SSH_PACKET_USED;
}
SSH_PACKET_CALLBACK(channel_rcv_eof) {
ssh_channel channel;
(void)user;
(void)type;
enter_function();
channel = channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS, "%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Received eof on channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
/* channel->remote_window = 0; */
channel->remote_eof = 1;
if(ssh_callbacks_exists(channel->callbacks, channel_eof_function)) {
channel->callbacks->channel_eof_function(channel->session,
channel,
channel->callbacks->userdata);
}
leave_function();
return SSH_PACKET_USED;
}
SSH_PACKET_CALLBACK(channel_rcv_close) {
ssh_channel channel;
(void)user;
(void)type;
enter_function();
channel = channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS, "%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Received close on channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
if ((channel->stdout_buffer &&
buffer_get_rest_len(channel->stdout_buffer) > 0) ||
(channel->stderr_buffer &&
buffer_get_rest_len(channel->stderr_buffer) > 0)) {
channel->delayed_close = 1;
} else {
channel->state = SSH_CHANNEL_STATE_CLOSED;
}
if (channel->remote_eof == 0) {
ssh_log(session, SSH_LOG_PACKET,
"Remote host not polite enough to send an eof before close");
}
channel->remote_eof = 1;
/*
* The remote eof doesn't break things if there was still data into read
* buffer because the eof is ignored until the buffer is empty.
*/
if(ssh_callbacks_exists(channel->callbacks, channel_close_function)) {
channel->callbacks->channel_close_function(channel->session,
channel,
channel->callbacks->userdata);
}
leave_function();
return SSH_PACKET_USED;
}
SSH_PACKET_CALLBACK(channel_rcv_request) {
ssh_channel channel;
ssh_string request_s;
char *request;
uint32_t status;
(void)user;
(void)type;
enter_function();
channel = channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS,"%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
request_s = buffer_get_ssh_string(packet);
if (request_s == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST");
leave_function();
return SSH_PACKET_USED;
}
request = ssh_string_to_char(request_s);
ssh_string_free(request_s);
if (request == NULL) {
leave_function();
return SSH_PACKET_USED;
}
buffer_get_u8(packet, (uint8_t *) &status);
if (strcmp(request,"exit-status") == 0) {
SAFE_FREE(request);
buffer_get_u32(packet, &status);
channel->exit_status = ntohl(status);
ssh_log(session, SSH_LOG_PACKET, "received exit-status %d", channel->exit_status);
if(ssh_callbacks_exists(channel->callbacks, channel_exit_status_function)) {
channel->callbacks->channel_exit_status_function(channel->session,
channel,
channel->exit_status,
channel->callbacks->userdata);
}
leave_function();
return SSH_PACKET_USED;
}
if (strcmp(request,"signal") == 0) {
ssh_string signal_str;
char *sig;
SAFE_FREE(request);
ssh_log(session, SSH_LOG_PACKET, "received signal");
signal_str = buffer_get_ssh_string(packet);
if (signal_str == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST");
leave_function();
return SSH_PACKET_USED;
}
sig = ssh_string_to_char(signal_str);
ssh_string_free(signal_str);
if (sig == NULL) {
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Remote connection sent a signal SIG %s", sig);
if(ssh_callbacks_exists(channel->callbacks, channel_signal_function)) {
channel->callbacks->channel_signal_function(channel->session,
channel,
sig,
channel->callbacks->userdata);
}
leave_function();
return SSH_PACKET_USED;
}
if (strcmp(request, "exit-signal") == 0) {
const char *core = "(core dumped)";
ssh_string tmp;
char *sig;
char *errmsg = NULL;
char *lang = NULL;
uint8_t i;
SAFE_FREE(request);
tmp = buffer_get_ssh_string(packet);
if (tmp == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST");
leave_function();
return SSH_PACKET_USED;
}
sig = ssh_string_to_char(tmp);
ssh_string_free(tmp);
if (sig == NULL) {
leave_function();
return SSH_PACKET_USED;
}
buffer_get_u8(packet, &i);
if (i == 0) {
core = "";
}
tmp = buffer_get_ssh_string(packet);
if (tmp == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST");
SAFE_FREE(sig);
leave_function();
return SSH_PACKET_USED;
}
errmsg = ssh_string_to_char(tmp);
ssh_string_free(tmp);
if (errmsg == NULL) {
SAFE_FREE(sig);
leave_function();
return SSH_PACKET_USED;
}
tmp = buffer_get_ssh_string(packet);
if (tmp == NULL) {
ssh_log(session, SSH_LOG_PACKET, "Invalid MSG_CHANNEL_REQUEST");
SAFE_FREE(errmsg);
SAFE_FREE(sig);
leave_function();
return SSH_PACKET_USED;
}
lang = ssh_string_to_char(tmp);
ssh_string_free(tmp);
if (lang == NULL) {
SAFE_FREE(errmsg);
SAFE_FREE(sig);
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Remote connection closed by signal SIG %s %s", sig, core);
if(ssh_callbacks_exists(channel->callbacks, channel_exit_signal_function)) {
channel->callbacks->channel_exit_signal_function(channel->session,
channel,
sig, i, errmsg, lang,
channel->callbacks->userdata);
}
SAFE_FREE(lang);
SAFE_FREE(errmsg);
SAFE_FREE(sig);
leave_function();
return SSH_PACKET_USED;
}
if(strcmp(request,"keepalive@openssh.com")==0){
SAFE_FREE(request);
ssh_log(session, SSH_LOG_PROTOCOL,"Responding to Openssh's keepalive");
buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_FAILURE);
buffer_add_u32(session->out_buffer, htonl(channel->remote_channel));
packet_send(session);
leave_function();
return SSH_PACKET_USED;
}
/* If we are here, that means we have a request that is not in the understood
* client requests. That means we need to create a ssh message to be passed
* to the user code handling ssh messages
*/
ssh_message_handle_channel_request(session,channel,packet,request,status);
SAFE_FREE(request);
leave_function();
return SSH_PACKET_USED;
}
/*
* When data has been received from the ssh server, it can be applied to the
* known user function, with help of the callback, or inserted here
*
* FIXME is the window changed?
*/
int channel_default_bufferize(ssh_channel channel, void *data, int len,
int is_stderr) {
ssh_session session;
if(channel == NULL) {
return -1;
}
session = channel->session;
if(data == NULL) {
ssh_set_error_invalid(session, __FUNCTION__);
return -1;
}
ssh_log(session, SSH_LOG_RARE,
"placing %d bytes into channel buffer (stderr=%d)", len, is_stderr);
if (is_stderr == 0) {
/* stdout */
if (channel->stdout_buffer == NULL) {
channel->stdout_buffer = ssh_buffer_new();
if (channel->stdout_buffer == NULL) {
ssh_set_error_oom(session);
return -1;
}
}
if (buffer_add_data(channel->stdout_buffer, data, len) < 0) {
ssh_set_error_oom(session);
ssh_buffer_free(channel->stdout_buffer);
channel->stdout_buffer = NULL;
return -1;
}
} else {
/* stderr */
if (channel->stderr_buffer == NULL) {
channel->stderr_buffer = ssh_buffer_new();
if (channel->stderr_buffer == NULL) {
ssh_set_error_oom(session);
return -1;
}
}
if (buffer_add_data(channel->stderr_buffer, data, len) < 0) {
ssh_set_error_oom(session);
ssh_buffer_free(channel->stderr_buffer);
channel->stderr_buffer = NULL;
return -1;
}
}
return 0;
}
/**
* @brief Open a session channel (suited for a shell, not TCP forwarding).
*
* @param[in] channel An allocated channel.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @see channel_open_forward()
* @see channel_request_env()
* @see channel_request_shell()
* @see channel_request_exec()
*/
int ssh_channel_open_session(ssh_channel channel) {
if(channel == NULL) {
return SSH_ERROR;
}
#ifdef WITH_SSH1
if (channel->session->version == 1) {
return channel_open_session1(channel);
}
#endif
return channel_open(channel,
"session",
CHANNEL_INITIAL_WINDOW,
CHANNEL_MAX_PACKET,
NULL);
}
/**
* @brief Open a TCP/IP forwarding channel.
*
* @param[in] channel An allocated channel.
*
* @param[in] remotehost The remote host to connected (host name or IP).
*
* @param[in] remoteport The remote port.
*
* @param[in] sourcehost The numeric IP address of the machine from where the
* connection request originates. This is mostly for
* logging purposes.
*
* @param[in] localport The port on the host from where the connection
* originated. This is mostly for logging purposes.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @warning This function does not bind the local port and does not automatically
* forward the content of a socket to the channel. You still have to
* use channel_read and channel_write for this.
*/
int ssh_channel_open_forward(ssh_channel channel, const char *remotehost,
int remoteport, const char *sourcehost, int localport) {
ssh_session session;
ssh_buffer payload = NULL;
ssh_string str = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return rc;
}
session = channel->session;
if(remotehost == NULL || sourcehost == NULL) {
ssh_set_error_invalid(session, __FUNCTION__);
return rc;
}
enter_function();
payload = ssh_buffer_new();
if (payload == NULL) {
ssh_set_error_oom(session);
goto error;
}
str = ssh_string_from_char(remotehost);
if (str == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(payload, str) < 0 ||
buffer_add_u32(payload,htonl(remoteport)) < 0) {
ssh_set_error_oom(session);
goto error;
}
ssh_string_free(str);
str = ssh_string_from_char(sourcehost);
if (str == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(payload, str) < 0 ||
buffer_add_u32(payload,htonl(localport)) < 0) {
ssh_set_error_oom(session);
goto error;
}
rc = channel_open(channel,
"direct-tcpip",
CHANNEL_INITIAL_WINDOW,
CHANNEL_MAX_PACKET,
payload);
error:
ssh_buffer_free(payload);
ssh_string_free(str);
leave_function();
return rc;
}
/**
* @brief Close and free a channel.
*
* @param[in] channel The channel to free.
*
* @warning Any data unread on this channel will be lost.
*/
void ssh_channel_free(ssh_channel channel) {
ssh_session session;
struct ssh_iterator *it;
if (channel == NULL) {
return;
}
session = channel->session;
enter_function();
if (session->alive && channel->state == SSH_CHANNEL_STATE_OPEN) {
ssh_channel_close(channel);
}
it = ssh_list_find(session->channels, channel);
if(it != NULL){
ssh_list_remove(session->channels, it);
}
ssh_buffer_free(channel->stdout_buffer);
ssh_buffer_free(channel->stderr_buffer);
/* debug trick to catch use after frees */
memset(channel, 'X', sizeof(struct ssh_channel_struct));
SAFE_FREE(channel);
leave_function();
}
/**
* @brief Send an end of file on the channel.
*
* This doesn't close the channel. You may still read from it but not write.
*
* @param[in] channel The channel to send the eof to.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @see channel_close()
* @see channel_free()
*/
int ssh_channel_send_eof(ssh_channel channel){
ssh_session session;
int rc = SSH_ERROR;
if(channel == NULL) {
return rc;
}
session = channel->session;
enter_function();
if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_EOF) < 0) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_u32(session->out_buffer,htonl(channel->remote_channel)) < 0) {
ssh_set_error_oom(session);
goto error;
}
rc = packet_send(session);
ssh_log(session, SSH_LOG_PACKET,
"Sent a EOF on client channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
channel->local_eof = 1;
leave_function();
return rc;
error:
buffer_reinit(session->out_buffer);
leave_function();
return rc;
}
/**
* @brief Close a channel.
*
* This sends an end of file and then closes the channel. You won't be able
* to recover any data the server was going to send or was in buffers.
*
* @param[in] channel The channel to close.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @see channel_free()
* @see channel_eof()
*/
int ssh_channel_close(ssh_channel channel){
ssh_session session;
int rc = 0;
if(channel == NULL) {
return SSH_ERROR;
}
session = channel->session;
enter_function();
if (channel->local_eof == 0) {
rc = ssh_channel_send_eof(channel);
}
if (rc != SSH_OK) {
leave_function();
return rc;
}
if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_CLOSE) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->remote_channel)) < 0) {
ssh_set_error_oom(session);
goto error;
}
rc = packet_send(session);
ssh_log(session, SSH_LOG_PACKET,
"Sent a close on client channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
if(rc == SSH_OK) {
channel->state=SSH_CHANNEL_STATE_CLOSED;
}
leave_function();
return rc;
error:
buffer_reinit(session->out_buffer);
leave_function();
return rc;
}
int channel_write_common(ssh_channel channel, const void *data,
uint32_t len, int is_stderr) {
ssh_session session;
uint32_t origlen = len;
size_t effectivelen;
size_t maxpacketlen;
int timeout;
int rc;
if(channel == NULL) {
return -1;
}
session = channel->session;
if(data == NULL) {
ssh_set_error_invalid(session, __FUNCTION__);
return -1;
}
if (len > INT_MAX) {
ssh_log(session, SSH_LOG_PROTOCOL,
"Length (%u) is bigger than INT_MAX", len);
return SSH_ERROR;
}
enter_function();
if(ssh_is_blocking(session))
timeout = -2;
else
timeout = 0;
/*
* Handle the max packet len from remote side, be nice
* 10 bytes for the headers
*/
maxpacketlen = channel->remote_maxpacket - 10;
if (channel->local_eof) {
ssh_set_error(session, SSH_REQUEST_DENIED,
"Can't write to channel %d:%d after EOF was sent",
channel->local_channel,
channel->remote_channel);
leave_function();
return -1;
}
if (channel->state != SSH_CHANNEL_STATE_OPEN || channel->delayed_close != 0) {
ssh_set_error(session, SSH_REQUEST_DENIED, "Remote channel is closed");
leave_function();
return -1;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
int rc = channel_write1(channel, data, len);
leave_function();
return rc;
}
#endif
while (len > 0) {
if (channel->remote_window < len) {
ssh_log(session, SSH_LOG_PROTOCOL,
"Remote window is %d bytes. going to write %d bytes",
channel->remote_window,
len);
/* What happens when the channel window is zero? */
if(channel->remote_window == 0) {
/* nothing can be written */
ssh_log(session, SSH_LOG_PROTOCOL,
"Wait for a growing window message...");
rc = ssh_handle_packets(session, timeout);
if (rc == SSH_ERROR || (channel->remote_window == 0 && timeout==0))
goto out;
continue;
}
effectivelen = len > channel->remote_window ? channel->remote_window : len;
} else {
effectivelen = len;
}
effectivelen = effectivelen > maxpacketlen ? maxpacketlen : effectivelen;
if (buffer_add_u8(session->out_buffer, is_stderr ?
SSH2_MSG_CHANNEL_EXTENDED_DATA : SSH2_MSG_CHANNEL_DATA) < 0 ||
buffer_add_u32(session->out_buffer,
htonl(channel->remote_channel)) < 0) {
ssh_set_error_oom(session);
goto error;
}
/* stderr message has an extra field */
if (is_stderr &&
buffer_add_u32(session->out_buffer, htonl(SSH2_EXTENDED_DATA_STDERR)) < 0) {
ssh_set_error_oom(session);
goto error;
}
/* append payload data */
if (buffer_add_u32(session->out_buffer, htonl(effectivelen)) < 0 ||
buffer_add_data(session->out_buffer, data, effectivelen) < 0) {
ssh_set_error_oom(session);
goto error;
}
if (packet_send(session) == SSH_ERROR) {
leave_function();
return SSH_ERROR;
}
ssh_log(session, SSH_LOG_RARE,
"channel_write wrote %ld bytes", (long int) effectivelen);
channel->remote_window -= effectivelen;
len -= effectivelen;
data = ((uint8_t*)data + effectivelen);
}
/* it's a good idea to flush the socket now */
do {
rc = ssh_handle_packets(session, timeout);
} while(ssh_socket_buffered_write_bytes(session->socket) > 0 && timeout != 0);
out:
leave_function();
return (int)(origlen - len);
error:
buffer_reinit(session->out_buffer);
leave_function();
return SSH_ERROR;
}
uint32_t ssh_channel_window_size(ssh_channel channel) {
return channel->remote_window;
}
/**
* @brief Blocking write on a channel.
*
* @param[in] channel The channel to write to.
*
* @param[in] data A pointer to the data to write.
*
* @param[in] len The length of the buffer to write to.
*
* @return The number of bytes written, SSH_ERROR on error.
*
* @see channel_read()
*/
int ssh_channel_write(ssh_channel channel, const void *data, uint32_t len) {
return channel_write_common(channel, data, len, 0);
}
/**
* @brief Check if the channel is open or not.
*
* @param[in] channel The channel to check.
*
* @return 0 if channel is closed, nonzero otherwise.
*
* @see channel_is_closed()
*/
int ssh_channel_is_open(ssh_channel channel) {
if(channel == NULL) {
return 0;
}
return (channel->state == SSH_CHANNEL_STATE_OPEN && channel->session->alive != 0);
}
/**
* @brief Check if the channel is closed or not.
*
* @param[in] channel The channel to check.
*
* @return 0 if channel is opened, nonzero otherwise.
*
* @see channel_is_open()
*/
int ssh_channel_is_closed(ssh_channel channel) {
if(channel == NULL) {
return SSH_ERROR;
}
return (channel->state != SSH_CHANNEL_STATE_OPEN || channel->session->alive == 0);
}
/**
* @brief Check if remote has sent an EOF.
*
* @param[in] channel The channel to check.
*
* @return 0 if there is no EOF, nonzero otherwise.
*/
int ssh_channel_is_eof(ssh_channel channel) {
if(channel == NULL) {
return SSH_ERROR;
}
if ((channel->stdout_buffer &&
buffer_get_rest_len(channel->stdout_buffer) > 0) ||
(channel->stderr_buffer &&
buffer_get_rest_len(channel->stderr_buffer) > 0)) {
return 0;
}
return (channel->remote_eof != 0);
}
/**
* @brief Put the channel into blocking or nonblocking mode.
*
* @param[in] channel The channel to use.
*
* @param[in] blocking A boolean for blocking or nonblocking.
*
* @warning A side-effect of this is to put the whole session
* in non-blocking mode.
* @see ssh_set_blocking()
*/
void ssh_channel_set_blocking(ssh_channel channel, int blocking) {
if(channel == NULL) {
return;
}
ssh_set_blocking(channel->session,blocking);
}
/**
* @internal
*
* @brief handle a SSH_CHANNEL_SUCCESS packet and set the channel state.
*
* This works on SSH1 sessions too.
*/
SSH_PACKET_CALLBACK(ssh_packet_channel_success){
ssh_channel channel;
(void)type;
(void)user;
enter_function();
channel=channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS, "%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Received SSH_CHANNEL_SUCCESS on channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
if(channel->request_state != SSH_CHANNEL_REQ_STATE_PENDING){
ssh_log(session, SSH_LOG_RARE, "SSH_CHANNEL_SUCCESS received in incorrect state %d",
channel->request_state);
} else {
channel->request_state=SSH_CHANNEL_REQ_STATE_ACCEPTED;
}
leave_function();
return SSH_PACKET_USED;
}
/**
* @internal
*
* @brief Handle a SSH_CHANNEL_FAILURE packet and set the channel state.
*
* This works on SSH1 sessions too.
*/
SSH_PACKET_CALLBACK(ssh_packet_channel_failure){
ssh_channel channel;
(void)type;
(void)user;
enter_function();
channel=channel_from_msg(session,packet);
if (channel == NULL) {
ssh_log(session, SSH_LOG_FUNCTIONS, "%s", ssh_get_error(session));
leave_function();
return SSH_PACKET_USED;
}
ssh_log(session, SSH_LOG_PACKET,
"Received SSH_CHANNEL_FAILURE on channel (%d:%d)",
channel->local_channel,
channel->remote_channel);
if(channel->request_state != SSH_CHANNEL_REQ_STATE_PENDING){
ssh_log(session, SSH_LOG_RARE, "SSH_CHANNEL_FAILURE received in incorrect state %d",
channel->request_state);
} else {
channel->request_state=SSH_CHANNEL_REQ_STATE_DENIED;
}
leave_function();
return SSH_PACKET_USED;
}
static int channel_request(ssh_channel channel, const char *request,
ssh_buffer buffer, int reply) {
ssh_session session = channel->session;
ssh_string req = NULL;
int timeout;
int rc = SSH_ERROR;
enter_function();
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
req = ssh_string_from_char(request);
if (req == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_REQUEST) < 0 ||
buffer_add_u32(session->out_buffer, htonl(channel->remote_channel)) < 0 ||
buffer_add_ssh_string(session->out_buffer, req) < 0 ||
buffer_add_u8(session->out_buffer, reply == 0 ? 0 : 1) < 0) {
ssh_set_error_oom(session);
goto error;
}
ssh_string_free(req);
if (buffer != NULL) {
if (buffer_add_data(session->out_buffer, buffer_get_rest(buffer),
buffer_get_rest_len(buffer)) < 0) {
ssh_set_error_oom(session);
goto error;
}
}
channel->request_state = SSH_CHANNEL_REQ_STATE_PENDING;
if (packet_send(session) == SSH_ERROR) {
leave_function();
return rc;
}
ssh_log(session, SSH_LOG_PACKET,
"Sent a SSH_MSG_CHANNEL_REQUEST %s", request);
if (reply == 0) {
channel->request_state = SSH_CHANNEL_REQ_STATE_NONE;
leave_function();
return SSH_OK;
}
pending:
if(ssh_is_blocking(session))
timeout=-2;
else
timeout=0;
while(channel->request_state == SSH_CHANNEL_REQ_STATE_PENDING){
ssh_handle_packets(session, timeout);
if(channel->request_state == SSH_CHANNEL_REQ_STATE_PENDING && timeout==0){
leave_function();
return SSH_AGAIN;
}
if(session->session_state == SSH_SESSION_STATE_ERROR) {
channel->request_state = SSH_CHANNEL_REQ_STATE_ERROR;
break;
}
}
/* we received something */
switch (channel->request_state){
case SSH_CHANNEL_REQ_STATE_ERROR:
rc=SSH_ERROR;
break;
case SSH_CHANNEL_REQ_STATE_DENIED:
ssh_set_error(session, SSH_REQUEST_DENIED,
"Channel request %s failed", request);
rc=SSH_ERROR;
break;
case SSH_CHANNEL_REQ_STATE_ACCEPTED:
ssh_log(session, SSH_LOG_PROTOCOL,
"Channel request %s success",request);
rc=SSH_OK;
break;
case SSH_CHANNEL_REQ_STATE_NONE:
case SSH_CHANNEL_REQ_STATE_PENDING:
/* Never reached */
ssh_set_error(session, SSH_FATAL, "Invalid state in channel_request()");
rc=SSH_ERROR;
break;
}
channel->request_state=SSH_CHANNEL_REQ_STATE_NONE;
leave_function();
return rc;
error:
buffer_reinit(session->out_buffer);
ssh_string_free(req);
leave_function();
return rc;
}
/**
* @brief Request a pty with a specific type and size.
*
* @param[in] channel The channel to sent the request.
*
* @param[in] terminal The terminal type ("vt100, xterm,...").
*
* @param[in] col The number of columns.
*
* @param[in] row The number of rows.
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
*/
int ssh_channel_request_pty_size(ssh_channel channel, const char *terminal,
int col, int row) {
ssh_session session = channel->session;
ssh_string term = NULL;
ssh_buffer buffer = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
if(terminal == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
enter_function();
#ifdef WITH_SSH1
if (channel->version==1) {
channel_request_pty_size1(channel,terminal, col, row);
leave_function();
return rc;
}
#endif
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(session);
goto error;
}
term = ssh_string_from_char(terminal);
if (term == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(buffer, term) < 0 ||
buffer_add_u32(buffer, htonl(col)) < 0 ||
buffer_add_u32(buffer, htonl(row)) < 0 ||
buffer_add_u32(buffer, 0) < 0 ||
buffer_add_u32(buffer, 0) < 0 ||
buffer_add_u32(buffer, htonl(1)) < 0 || /* Add a 0byte string */
buffer_add_u8(buffer, 0) < 0) {
ssh_set_error_oom(session);
goto error;
}
pending:
rc = channel_request(channel, "pty-req", buffer, 1);
error:
ssh_buffer_free(buffer);
ssh_string_free(term);
leave_function();
return rc;
}
/**
* @brief Request a PTY.
*
* @param[in] channel The channel to send the request.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @see channel_request_pty_size()
*/
int ssh_channel_request_pty(ssh_channel channel) {
return ssh_channel_request_pty_size(channel, "xterm", 80, 24);
}
/**
* @brief Change the size of the terminal associated to a channel.
*
* @param[in] channel The channel to change the size.
*
* @param[in] cols The new number of columns.
*
* @param[in] rows The new number of rows.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @warning Do not call it from a signal handler if you are not sure any other
* libssh function using the same channel/session is running at same
* time (not 100% threadsafe).
*/
int ssh_channel_change_pty_size(ssh_channel channel, int cols, int rows) {
ssh_session session = channel->session;
ssh_buffer buffer = NULL;
int rc = SSH_ERROR;
enter_function();
#ifdef WITH_SSH1
if (channel->version == 1) {
rc = channel_change_pty_size1(channel,cols,rows);
leave_function();
return rc;
}
#endif
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_u32(buffer, htonl(cols)) < 0 ||
buffer_add_u32(buffer, htonl(rows)) < 0 ||
buffer_add_u32(buffer, 0) < 0 ||
buffer_add_u32(buffer, 0) < 0) {
ssh_set_error_oom(session);
goto error;
}
rc = channel_request(channel, "window-change", buffer, 0);
error:
ssh_buffer_free(buffer);
leave_function();
return rc;
}
/**
* @brief Request a shell.
*
* @param[in] channel The channel to send the request.
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
*/
int ssh_channel_request_shell(ssh_channel channel) {
if(channel == NULL) {
return SSH_ERROR;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
return channel_request_shell1(channel);
}
#endif
return channel_request(channel, "shell", NULL, 1);
}
/**
* @brief Request a subsystem (for example "sftp").
*
* @param[in] channel The channel to send the request.
*
* @param[in] subsys The subsystem to request (for example "sftp").
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
*
* @warning You normally don't have to call it for sftp, see sftp_new().
*/
int ssh_channel_request_subsystem(ssh_channel channel, const char *subsys) {
ssh_buffer buffer = NULL;
ssh_string subsystem = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
if(subsys == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
subsystem = ssh_string_from_char(subsys);
if (subsystem == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, subsystem) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
pending:
rc = channel_request(channel, "subsystem", buffer, 1);
error:
ssh_buffer_free(buffer);
ssh_string_free(subsystem);
return rc;
}
int ssh_channel_request_sftp( ssh_channel channel){
if(channel == NULL) {
return SSH_ERROR;
}
return ssh_channel_request_subsystem(channel, "sftp");
}
static ssh_string generate_cookie(void) {
static const char *hex = "0123456789abcdef";
char s[36];
char rnd[16];
int i;
ssh_get_random(rnd,sizeof(rnd),0);
for (i = 0; i < 16; i++) {
s[i*2] = hex[rnd[i] & 0x0f];
s[i*2+1] = hex[rnd[i] >> 4];
}
s[32] = '\0';
return ssh_string_from_char(s);
}
/**
* @brief Sends the "x11-req" channel request over an existing session channel.
*
* This will enable redirecting the display of the remote X11 applications to
* local X server over an secure tunnel.
*
* @param[in] channel An existing session channel where the remote X11
* applications are going to be executed.
*
* @param[in] single_connection A boolean to mark only one X11 app will be
* redirected.
*
* @param[in] protocol A x11 authentication protocol. Pass NULL to use the
* default value MIT-MAGIC-COOKIE-1.
*
* @param[in] cookie A x11 authentication cookie. Pass NULL to generate
* a random cookie.
*
* @param[in] screen_number The screen number.
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
*/
int ssh_channel_request_x11(ssh_channel channel, int single_connection, const char *protocol,
const char *cookie, int screen_number) {
ssh_buffer buffer = NULL;
ssh_string p = NULL;
ssh_string c = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
p = ssh_string_from_char(protocol ? protocol : "MIT-MAGIC-COOKIE-1");
if (p == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (cookie) {
c = ssh_string_from_char(cookie);
} else {
c = generate_cookie();
}
if (c == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_u8(buffer, single_connection == 0 ? 0 : 1) < 0 ||
buffer_add_ssh_string(buffer, p) < 0 ||
buffer_add_ssh_string(buffer, c) < 0 ||
buffer_add_u32(buffer, htonl(screen_number)) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
pending:
rc = channel_request(channel, "x11-req", buffer, 1);
error:
ssh_buffer_free(buffer);
ssh_string_free(p);
ssh_string_free(c);
return rc;
}
static ssh_channel ssh_channel_accept(ssh_session session, int channeltype,
int timeout_ms) {
#ifndef _WIN32
static const struct timespec ts = {
.tv_sec = 0,
.tv_nsec = 50000000 /* 50ms */
};
#endif
ssh_message msg = NULL;
ssh_channel channel = NULL;
struct ssh_iterator *iterator;
int t;
for (t = timeout_ms; t >= 0; t -= 50)
{
ssh_handle_packets(session, 50);
if (session->ssh_message_list) {
iterator = ssh_list_get_iterator(session->ssh_message_list);
while (iterator) {
msg = (ssh_message)iterator->data;
if (ssh_message_type(msg) == SSH_REQUEST_CHANNEL_OPEN &&
ssh_message_subtype(msg) == channeltype) {
ssh_list_remove(session->ssh_message_list, iterator);
channel = ssh_message_channel_request_open_reply_accept(msg);
ssh_message_free(msg);
return channel;
}
iterator = iterator->next;
}
}
if(t>0){
#ifdef _WIN32
Sleep(50); /* 50ms */
#else
nanosleep(&ts, NULL);
#endif
}
}
ssh_set_error(session, SSH_NO_ERROR, "No channel request of this type from server");
return NULL;
}
/**
* @brief Accept an X11 forwarding channel.
*
* @param[in] channel An x11-enabled session channel.
*
* @param[in] timeout_ms Timeout in milliseconds.
*
* @return A newly created channel, or NULL if no X11 request from
* the server.
*/
ssh_channel ssh_channel_accept_x11(ssh_channel channel, int timeout_ms) {
return ssh_channel_accept(channel->session, SSH_CHANNEL_X11, timeout_ms);
}
/**
* @internal
*
* @brief Handle a SSH_REQUEST_SUCCESS packet normally sent after a global
* request.
*/
SSH_PACKET_CALLBACK(ssh_request_success){
(void)type;
(void)user;
(void)packet;
enter_function();
ssh_log(session, SSH_LOG_PACKET,
"Received SSH_REQUEST_SUCCESS");
if(session->global_req_state != SSH_CHANNEL_REQ_STATE_PENDING){
ssh_log(session, SSH_LOG_RARE, "SSH_REQUEST_SUCCESS received in incorrect state %d",
session->global_req_state);
} else {
session->global_req_state=SSH_CHANNEL_REQ_STATE_ACCEPTED;
}
leave_function();
return SSH_PACKET_USED;
}
/**
* @internal
*
* @brief Handle a SSH_REQUEST_DENIED packet normally sent after a global
* request.
*/
SSH_PACKET_CALLBACK(ssh_request_denied){
(void)type;
(void)user;
(void)packet;
enter_function();
ssh_log(session, SSH_LOG_PACKET,
"Received SSH_REQUEST_FAILURE");
if(session->global_req_state != SSH_CHANNEL_REQ_STATE_PENDING){
ssh_log(session, SSH_LOG_RARE, "SSH_REQUEST_DENIED received in incorrect state %d",
session->global_req_state);
} else {
session->global_req_state=SSH_CHANNEL_REQ_STATE_DENIED;
}
leave_function();
return SSH_PACKET_USED;
}
/**
* @internal
*
* @brief Send a global request (needed for forward listening) and wait for the
* result.
*
* @param[in] session The SSH session handle.
*
* @param[in] request The type of request (defined in RFC).
*
* @param[in] buffer Additional data to put in packet.
*
* @param[in] reply Set if you expect a reply from server.
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
*/
static int global_request(ssh_session session, const char *request,
ssh_buffer buffer, int reply) {
ssh_string req = NULL;
int rc = SSH_ERROR;
int timeout;
enter_function();
if(session->global_req_state != SSH_CHANNEL_REQ_STATE_NONE)
goto pending;
req = ssh_string_from_char(request);
if (req == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_u8(session->out_buffer, SSH2_MSG_GLOBAL_REQUEST) < 0 ||
buffer_add_ssh_string(session->out_buffer, req) < 0 ||
buffer_add_u8(session->out_buffer, reply == 0 ? 0 : 1) < 0) {
ssh_set_error_oom(session);
goto error;
}
ssh_string_free(req);
req=NULL;
if (buffer != NULL) {
if (buffer_add_data(session->out_buffer, buffer_get_rest(buffer),
buffer_get_rest_len(buffer)) < 0) {
ssh_set_error_oom(session);
goto error;
}
}
session->global_req_state = SSH_CHANNEL_REQ_STATE_PENDING;
if (packet_send(session) == SSH_ERROR) {
leave_function();
return rc;
}
ssh_log(session, SSH_LOG_PACKET,
"Sent a SSH_MSG_GLOBAL_REQUEST %s", request);
if (reply == 0) {
session->global_req_state=SSH_CHANNEL_REQ_STATE_NONE;
leave_function();
return SSH_OK;
}
pending:
if(ssh_is_blocking(session))
timeout=-2;
else
timeout=0;
while(session->global_req_state == SSH_CHANNEL_REQ_STATE_PENDING){
rc=ssh_handle_packets(session, timeout);
if(rc==SSH_ERROR){
session->global_req_state = SSH_CHANNEL_REQ_STATE_ERROR;
break;
}
if(session->global_req_state == SSH_CHANNEL_REQ_STATE_PENDING
&& timeout == 0)
break;
}
switch(session->global_req_state){
case SSH_CHANNEL_REQ_STATE_ACCEPTED:
ssh_log(session, SSH_LOG_PROTOCOL, "Global request %s success",request);
rc=SSH_OK;
break;
case SSH_CHANNEL_REQ_STATE_DENIED:
ssh_log(session, SSH_LOG_PACKET,
"Global request %s failed", request);
ssh_set_error(session, SSH_REQUEST_DENIED,
"Global request %s failed", request);
rc=SSH_ERROR;
break;
case SSH_CHANNEL_REQ_STATE_ERROR:
case SSH_CHANNEL_REQ_STATE_NONE:
rc=SSH_ERROR;
break;
case SSH_CHANNEL_REQ_STATE_PENDING:
rc=SSH_AGAIN;
break;
}
leave_function();
return rc;
error:
ssh_string_free(req);
leave_function();
return rc;
}
/**
* @brief Sends the "tcpip-forward" global request to ask the server to begin
* listening for inbound connections.
*
* @param[in] session The ssh session to send the request.
*
* @param[in] address The address to bind to on the server. Pass NULL to bind
* to all available addresses on all protocol families
* supported by the server.
*
* @param[in] port The port to bind to on the server. Pass 0 to ask the
* server to allocate the next available unprivileged port
* number
*
* @param[in] bound_port The pointer to get actual bound port. Pass NULL to
* ignore.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*/
int ssh_forward_listen(ssh_session session, const char *address, int port, int *bound_port) {
ssh_buffer buffer = NULL;
ssh_string addr = NULL;
int rc = SSH_ERROR;
uint32_t tmp;
if(session->global_req_state != SSH_CHANNEL_REQ_STATE_NONE)
goto pending;
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(session);
goto error;
}
addr = ssh_string_from_char(address ? address : "");
if (addr == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(buffer, addr) < 0 ||
buffer_add_u32(buffer, htonl(port)) < 0) {
ssh_set_error_oom(session);
goto error;
}
pending:
rc = global_request(session, "tcpip-forward", buffer, 1);
/* TODO: FIXME no guarantee the last packet we received contains
* that info */
if (rc == SSH_OK && port == 0 && bound_port) {
buffer_get_u32(session->in_buffer, &tmp);
*bound_port = ntohl(tmp);
}
error:
ssh_buffer_free(buffer);
ssh_string_free(addr);
return rc;
}
/**
* @brief Accept an incoming TCP/IP forwarding channel.
*
* @param[in] session The ssh session to use.
*
* @param[in] timeout_ms A timeout in milliseconds.
*
* @return Newly created channel, or NULL if no incoming channel request from
* the server
*/
ssh_channel ssh_forward_accept(ssh_session session, int timeout_ms) {
return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms);
}
/**
* @brief Sends the "cancel-tcpip-forward" global request to ask the server to
* cancel the tcpip-forward request.
*
* @param[in] session The ssh session to send the request.
*
* @param[in] address The bound address on the server.
*
* @param[in] port The bound port on the server.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*/
int ssh_forward_cancel(ssh_session session, const char *address, int port) {
ssh_buffer buffer = NULL;
ssh_string addr = NULL;
int rc = SSH_ERROR;
if(session->global_req_state != SSH_CHANNEL_REQ_STATE_NONE)
goto pending;
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(session);
goto error;
}
addr = ssh_string_from_char(address ? address : "");
if (addr == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(buffer, addr) < 0 ||
buffer_add_u32(buffer, htonl(port)) < 0) {
ssh_set_error_oom(session);
goto error;
}
pending:
rc = global_request(session, "cancel-tcpip-forward", buffer, 1);
error:
ssh_buffer_free(buffer);
ssh_string_free(addr);
return rc;
}
/**
* @brief Set environment variables.
*
* @param[in] channel The channel to set the environment variables.
*
* @param[in] name The name of the variable.
*
* @param[in] value The value to set.
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
* @warning Some environment variables may be refused by security reasons.
*/
int ssh_channel_request_env(ssh_channel channel, const char *name, const char *value) {
ssh_buffer buffer = NULL;
ssh_string str = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
if(name == NULL || value == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
str = ssh_string_from_char(name);
if (str == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, str) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
ssh_string_free(str);
str = ssh_string_from_char(value);
if (str == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, str) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
pending:
rc = channel_request(channel, "env", buffer,1);
error:
ssh_buffer_free(buffer);
ssh_string_free(str);
return rc;
}
/**
* @brief Run a shell command without an interactive shell.
*
* This is similar to 'sh -c command'.
*
* @param[in] channel The channel to execute the command.
*
* @param[in] cmd The command to execute
* (e.g. "ls ~/ -al | grep -i reports").
*
* @return SSH_OK on success,
* SSH_ERROR if an error occurred,
* SSH_AGAIN if in nonblocking mode and call has
* to be done again.
* @code
* rc = channel_request_exec(channel, "ps aux");
* if (rc > 0) {
* return -1;
* }
*
* while ((rc = channel_read(channel, buffer, sizeof(buffer), 0)) > 0) {
* if (fwrite(buffer, 1, rc, stdout) != (unsigned int) rc) {
* return -1;
* }
* }
* @endcode
*
* @see channel_request_shell()
*/
int ssh_channel_request_exec(ssh_channel channel, const char *cmd) {
ssh_buffer buffer = NULL;
ssh_string command = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
if(cmd == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
return channel_request_exec1(channel, cmd);
}
#endif
switch(channel->request_state){
case SSH_CHANNEL_REQ_STATE_NONE:
break;
default:
goto pending;
}
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
command = ssh_string_from_char(cmd);
if (command == NULL) {
goto error;
ssh_set_error_oom(channel->session);
}
if (buffer_add_ssh_string(buffer, command) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
pending:
rc = channel_request(channel, "exec", buffer, 1);
error:
ssh_buffer_free(buffer);
ssh_string_free(command);
return rc;
}
/**
* @brief Send a signal to remote process (as described in RFC 4254, section 6.9).
*
* Sends a signal 'sig' to the remote process.
* Note, that remote system may not support signals concept.
* In such a case this request will be silently ignored.
* Only SSH-v2 is supported (I'm not sure about SSH-v1).
*
* OpenSSH doesn't support signals yet, see:
* https://bugzilla.mindrot.org/show_bug.cgi?id=1424
*
* @param[in] channel The channel to send signal.
*
* @param[in] sig The signal to send (without SIG prefix)
* \n\n
* SIGABRT -> ABRT \n
* SIGALRM -> ALRM \n
* SIGFPE -> FPE \n
* SIGHUP -> HUP \n
* SIGILL -> ILL \n
* SIGINT -> INT \n
* SIGKILL -> KILL \n
* SIGPIPE -> PIPE \n
* SIGQUIT -> QUIT \n
* SIGSEGV -> SEGV \n
* SIGTERM -> TERM \n
* SIGUSR1 -> USR1 \n
* SIGUSR2 -> USR2 \n
*
* @return SSH_OK on success, SSH_ERROR if an error occured
* (including attempts to send signal via SSH-v1 session).
*/
int ssh_channel_request_send_signal(ssh_channel channel, const char *sig) {
ssh_buffer buffer = NULL;
ssh_string encoded_signal = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
if(sig == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
return SSH_ERROR; // TODO: Add support for SSH-v1 if possible.
}
#endif
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
encoded_signal = ssh_string_from_char(sig);
if (encoded_signal == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, encoded_signal) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
rc = channel_request(channel, "signal", buffer, 0);
error:
ssh_buffer_free(buffer);
ssh_string_free(encoded_signal);
return rc;
}
/**
* @brief Read data from a channel into a buffer.
*
* @param[in] channel The channel to read from.
*
* @param[in] buffer The buffer which will get the data.
*
* @param[in] count The count of bytes to be read. If it is bigger than 0,
* the exact size will be read, else (bytes=0) it will
* return once anything is available.
*
* @param is_stderr A boolean value to mark reading from the stderr stream.
*
* @return The number of bytes read, 0 on end of file or SSH_ERROR
* on error.
* @deprecated Please use ssh_channel_read instead
* @see ssh_channel_read
*/
int channel_read_buffer(ssh_channel channel, ssh_buffer buffer, uint32_t count,
int is_stderr) {
ssh_session session=channel->session;
char buffer_tmp[8192];
int r;
uint32_t total=0;
if(channel == NULL) {
return SSH_ERROR;
}
if(buffer == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return SSH_ERROR;
}
enter_function();
buffer_reinit(buffer);
if(count==0){
do {
r=ssh_channel_poll(channel, is_stderr);
if(r < 0){
leave_function();
return r;
}
if(r > 0){
r=ssh_channel_read(channel, buffer_tmp, r, is_stderr);
if(r < 0){
leave_function();
return r;
}
if(buffer_add_data(buffer,buffer_tmp,r) < 0){
ssh_set_error_oom(session);
r = SSH_ERROR;
}
leave_function();
return r;
}
if(ssh_channel_is_eof(channel)){
leave_function();
return 0;
}
ssh_handle_packets(channel->session, -2);
} while (r == 0);
}
while(total < count){
r=ssh_channel_read(channel, buffer_tmp, sizeof(buffer_tmp), is_stderr);
if(r<0){
leave_function();
return r;
}
if(r==0){
leave_function();
return total;
}
if(buffer_add_data(buffer,buffer_tmp,r) < 0){
ssh_set_error_oom(session);
leave_function();
return SSH_ERROR;
}
total += r;
}
leave_function();
return total;
}
/* TODO FIXME Fix the delayed close thing */
/* TODO FIXME Fix the blocking behaviours */
/**
* @brief Reads data from a channel.
*
* @param[in] channel The channel to read from.
*
* @param[in] dest The destination buffer which will get the data.
*
* @param[in] count The count of bytes to be read.
*
* @param[in] is_stderr A boolean value to mark reading from the stderr flow.
*
* @return The number of bytes read, 0 on end of file or SSH_ERROR
* on error.
*
* @warning This function may return less than count bytes of data, and won't
* block until count bytes have been read.
* @warning The read function using a buffer has been renamed to
* channel_read_buffer().
*/
int ssh_channel_read(ssh_channel channel, void *dest, uint32_t count, int is_stderr) {
ssh_session session;
ssh_buffer stdbuf;
uint32_t len;
int rc;
if(channel == NULL) {
return SSH_ERROR;
}
if(dest == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return SSH_ERROR;
}
session = channel->session;
stdbuf = channel->stdout_buffer;
enter_function();
if (count == 0) {
leave_function();
return 0;
}
if (is_stderr) {
stdbuf=channel->stderr_buffer;
}
/*
* We may have problem if the window is too small to accept as much data
* as asked
*/
ssh_log(session, SSH_LOG_PROTOCOL,
"Read (%d) buffered : %d bytes. Window: %d",
count,
buffer_get_rest_len(stdbuf),
channel->local_window);
if (count > buffer_get_rest_len(stdbuf) + channel->local_window) {
if (grow_window(session, channel, count - buffer_get_rest_len(stdbuf)) < 0) {
leave_function();
return -1;
}
}
/* block reading until at least one byte is read
* and ignore the trivial case count=0
*/
while (buffer_get_rest_len(stdbuf) == 0 && count > 0) {
if (channel->remote_eof && buffer_get_rest_len(stdbuf) == 0) {
leave_function();
return 0;
}
if (channel->remote_eof) {
/* Return the resting bytes in buffer */
break;
}
if (buffer_get_rest_len(stdbuf) >= count) {
/* Stop reading when buffer is full enough */
break;
}
rc = ssh_handle_packets(session, -2);
if (rc != SSH_OK) {
return rc;
}
}
len = buffer_get_rest_len(stdbuf);
/* Read count bytes if len is greater, everything otherwise */
len = (len > count ? count : len);
memcpy(dest, buffer_get_rest(stdbuf), len);
buffer_pass_bytes(stdbuf,len);
/* Authorize some buffering while userapp is busy */
if (channel->local_window < WINDOWLIMIT) {
if (grow_window(session, channel, 0) < 0) {
leave_function();
return -1;
}
}
leave_function();
return len;
}
/**
* @brief Do a nonblocking read on the channel.
*
* A nonblocking read on the specified channel. it will return <= count bytes of
* data read atomically.
*
* @param[in] channel The channel to read from.
*
* @param[in] dest A pointer to a destination buffer.
*
* @param[in] count The count of bytes of data to be read.
*
* @param[in] is_stderr A boolean to select the stderr stream.
*
* @return The number of bytes read, 0 if nothing is available or
* SSH_ERROR on error.
*
* @warning Don't forget to check for EOF as it would return 0 here.
*
* @see channel_is_eof()
*/
int ssh_channel_read_nonblocking(ssh_channel channel, void *dest, uint32_t count,
int is_stderr) {
ssh_session session;
int to_read;
int rc;
if(channel == NULL) {
return SSH_ERROR;
}
if(dest == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return SSH_ERROR;
}
session = channel->session;
enter_function();
to_read = ssh_channel_poll(channel, is_stderr);
if (to_read <= 0) {
leave_function();
return to_read; /* may be an error code */
}
if (to_read > (int)count) {
to_read = (int)count;
}
rc = ssh_channel_read(channel, dest, to_read, is_stderr);
leave_function();
return rc;
}
/**
* @brief Polls a channel for data to read.
*
* @param[in] channel The channel to poll.
*
* @param[in] is_stderr A boolean to select the stderr stream.
*
* @return The number of bytes available for reading, 0 if nothing
* is available or SSH_ERROR on error.
*
* @warning When the channel is in EOF state, the function returns SSH_EOF.
*
* @see channel_is_eof()
*/
int ssh_channel_poll(ssh_channel channel, int is_stderr){
ssh_session session;
ssh_buffer stdbuf;
if(channel == NULL) {
return SSH_ERROR;
}
session = channel->session;
stdbuf = channel->stdout_buffer;
enter_function();
if (is_stderr) {
stdbuf = channel->stderr_buffer;
}
if (buffer_get_rest_len(stdbuf) == 0 && channel->remote_eof == 0) {
if (ssh_handle_packets(channel->session, 0)==SSH_ERROR) {
leave_function();
return SSH_ERROR;
}
}
if (buffer_get_rest_len(stdbuf) > 0){
leave_function();
return buffer_get_rest_len(stdbuf);
}
if (channel->remote_eof) {
leave_function();
return SSH_EOF;
}
leave_function();
return buffer_get_rest_len(stdbuf);
}
/**
* @brief Polls a channel for data to read, waiting for a certain timeout.
*
* @param[in] channel The channel to poll.
* @param[in] timeout Set an upper limit on the time for which this function
* will block, in milliseconds. Specifying a negative value
* means an infinite timeout. This parameter is passed to
* the poll() function.
* @param[in] is_stderr A boolean to select the stderr stream.
*
* @return The number of bytes available for reading,
* 0 if nothing is available (timeout elapsed),
* SSH_EOF on end of file,
* SSH_ERROR on error.
*
* @warning When the channel is in EOF state, the function returns SSH_EOF.
*
* @see channel_is_eof()
*/
int ssh_channel_poll_timeout(ssh_channel channel, int timeout, int is_stderr){
ssh_session session;
ssh_buffer stdbuf;
struct ssh_channel_read_termination_struct ctx;
int rc;
if(channel == NULL) {
return SSH_ERROR;
}
session = channel->session;
stdbuf = channel->stdout_buffer;
enter_function();
if (is_stderr) {
stdbuf = channel->stderr_buffer;
}
ctx.buffer = stdbuf;
ctx.channel = channel;
ctx.count = 1;
rc = ssh_handle_packets_termination(channel->session, timeout,
ssh_channel_read_termination, &ctx);
if(rc ==SSH_ERROR || session->session_state == SSH_SESSION_STATE_ERROR){
rc = SSH_ERROR;
goto end;
}
rc = buffer_get_rest_len(stdbuf);
if(rc > 0)
goto end;
if (channel->remote_eof)
rc = SSH_EOF;
end:
leave_function();
return rc;
}
/**
* @brief Recover the session in which belongs a channel.
*
* @param[in] channel The channel to recover the session from.
*
* @return The session pointer.
*/
ssh_session ssh_channel_get_session(ssh_channel channel) {
if(channel == NULL) {
return NULL;
}
return channel->session;
}
/**
* @brief Get the exit status of the channel (error code from the executed
* instruction).
*
* @param[in] channel The channel to get the status from.
*
* @returns The exit status, -1 if no exit status has been returned
* or eof not sent.
*/
int ssh_channel_get_exit_status(ssh_channel channel) {
int timeout;
if(channel == NULL) {
return SSH_ERROR;
}
if (channel->local_eof == 0) {
return channel->exit_status;
}
if(ssh_is_blocking(channel->session))
timeout = -2;
else
timeout = 0;
while ((channel->remote_eof == 0 || channel->exit_status == -1) && channel->session->alive) {
/* Parse every incoming packet */
if (ssh_handle_packets(channel->session, timeout) != SSH_OK) {
return -1;
}
/* XXX We should actually wait for a close packet and not a close
* we issued ourselves
*/
if (channel->state != SSH_CHANNEL_STATE_OPEN) {
/* When a channel is closed, no exit status message can
* come anymore */
break;
}
if (timeout == 0)
break;
}
return channel->exit_status;
}
/*
* This function acts as a meta select.
*
* First, channels are analyzed to seek potential can-write or can-read ones,
* then if no channel has been elected, it goes in a loop with the posix
* select(2).
* This is made in two parts: protocol select and network select. The protocol
* select does not use the network functions at all
*/
static int channel_protocol_select(ssh_channel *rchans, ssh_channel *wchans,
ssh_channel *echans, ssh_channel *rout, ssh_channel *wout, ssh_channel *eout) {
ssh_channel chan;
int i;
int j = 0;
for (i = 0; rchans[i] != NULL; i++) {
chan = rchans[i];
while (ssh_channel_is_open(chan) && ssh_socket_data_available(chan->session->socket)) {
ssh_handle_packets(chan->session, -2);
}
if ((chan->stdout_buffer && buffer_get_rest_len(chan->stdout_buffer) > 0) ||
(chan->stderr_buffer && buffer_get_rest_len(chan->stderr_buffer) > 0) ||
chan->remote_eof) {
rout[j] = chan;
j++;
}
}
rout[j] = NULL;
j = 0;
for(i = 0; wchans[i] != NULL; i++) {
chan = wchans[i];
/* It's not our business to seek if the file descriptor is writable */
if (ssh_socket_data_writable(chan->session->socket) &&
ssh_channel_is_open(chan) && (chan->remote_window > 0)) {
wout[j] = chan;
j++;
}
}
wout[j] = NULL;
j = 0;
for (i = 0; echans[i] != NULL; i++) {
chan = echans[i];
if (!ssh_socket_is_open(chan->session->socket) || ssh_channel_is_closed(chan)) {
eout[j] = chan;
j++;
}
}
eout[j] = NULL;
return 0;
}
/* Just count number of pointers in the array */
static int count_ptrs(ssh_channel *ptrs) {
int c;
for (c = 0; ptrs[c] != NULL; c++)
;
return c;
}
/**
* @brief Act like the standard select(2) on channels.
*
* The list of pointers are then actualized and will only contain pointers to
* channels that are respectively readable, writable or have an exception to
* trap.
*
* @param[in] readchans A NULL pointer or an array of channel pointers,
* terminated by a NULL.
*
* @param[in] writechans A NULL pointer or an array of channel pointers,
* terminated by a NULL.
*
* @param[in] exceptchans A NULL pointer or an array of channel pointers,
* terminated by a NULL.
*
* @param[in] timeout Timeout as defined by select(2).
*
* @return SSH_OK on a successful operation, SSH_EINTR if the
* select(2) syscall was interrupted, then relaunch the
* function.
*/
int ssh_channel_select(ssh_channel *readchans, ssh_channel *writechans,
ssh_channel *exceptchans, struct timeval * timeout) {
ssh_channel *rchans, *wchans, *echans;
ssh_channel dummy = NULL;
ssh_event event = NULL;
int rc;
int i;
int tm, tm_base;
int firstround=1;
struct ssh_timestamp ts;
if (timeout != NULL)
tm_base = timeout->tv_sec * 1000 + timeout->tv_usec/1000;
else
tm_base = SSH_TIMEOUT_INFINITE;
ssh_timestamp_init(&ts);
tm = tm_base;
/* don't allow NULL pointers */
if (readchans == NULL) {
readchans = &dummy;
}
if (writechans == NULL) {
writechans = &dummy;
}
if (exceptchans == NULL) {
exceptchans = &dummy;
}
if (readchans[0] == NULL && writechans[0] == NULL && exceptchans[0] == NULL) {
/* No channel to poll?? Go away! */
return 0;
}
/* Prepare the outgoing temporary arrays */
rchans = malloc(sizeof(ssh_channel ) * (count_ptrs(readchans) + 1));
if (rchans == NULL) {
return SSH_ERROR;
}
wchans = malloc(sizeof(ssh_channel ) * (count_ptrs(writechans) + 1));
if (wchans == NULL) {
SAFE_FREE(rchans);
return SSH_ERROR;
}
echans = malloc(sizeof(ssh_channel ) * (count_ptrs(exceptchans) + 1));
if (echans == NULL) {
SAFE_FREE(rchans);
SAFE_FREE(wchans);
return SSH_ERROR;
}
/*
* First, try without doing network stuff then, use the ssh_poll
* infrastructure to poll on all sessions.
*/
do {
channel_protocol_select(readchans, writechans, exceptchans,
rchans, wchans, echans);
if (rchans[0] != NULL || wchans[0] != NULL || echans[0] != NULL) {
/* At least one channel has an event */
break;
}
/* Add all channels' sessions right into an event object */
if (!event){
event = ssh_event_new();
if(!event){
return SSH_ERROR;
}
for (i = 0; readchans[i] != NULL; i++) {
ssh_poll_get_default_ctx(readchans[i]->session);
ssh_event_add_session(event, readchans[i]->session);
}
for (i = 0; writechans[i] != NULL; i++) {
ssh_poll_get_default_ctx(writechans[i]->session);
ssh_event_add_session(event, writechans[i]->session);
}
for (i = 0; exceptchans[i] != NULL; i++) {
ssh_poll_get_default_ctx(exceptchans[i]->session);
ssh_event_add_session(event, exceptchans[i]->session);
}
}
/* Get out if the timeout has elapsed */
if (!firstround && ssh_timeout_elapsed(&ts, tm_base)){
break;
}
/* Here we go */
rc = ssh_event_dopoll(event,tm);
if (rc != SSH_OK){
SAFE_FREE(rchans);
SAFE_FREE(wchans);
SAFE_FREE(echans);
ssh_event_free(event);
return rc;
}
tm = ssh_timeout_update(&ts, tm_base);
firstround=0;
} while(1);
memcpy(readchans, rchans, (count_ptrs(rchans) + 1) * sizeof(ssh_channel ));
memcpy(writechans, wchans, (count_ptrs(wchans) + 1) * sizeof(ssh_channel ));
memcpy(exceptchans, echans, (count_ptrs(echans) + 1) * sizeof(ssh_channel ));
SAFE_FREE(rchans);
SAFE_FREE(wchans);
SAFE_FREE(echans);
if(event)
ssh_event_free(event);
return 0;
}
#if WITH_SERVER
/**
* @brief Blocking write on a channel stderr.
*
* @param[in] channel The channel to write to.
*
* @param[in] data A pointer to the data to write.
*
* @param[in] len The length of the buffer to write to.
*
* @return The number of bytes written, SSH_ERROR on error.
*
* @see channel_read()
*/
int ssh_channel_write_stderr(ssh_channel channel, const void *data, uint32_t len) {
return channel_write_common(channel, data, len, 1);
}
/**
* @brief Open a TCP/IP reverse forwarding channel.
*
* @param[in] channel An allocated channel.
*
* @param[in] remotehost The remote host to connected (host name or IP).
*
* @param[in] remoteport The remote port.
*
* @param[in] sourcehost The source host (your local computer). It's optional
* and for logging purpose.
*
* @param[in] localport The source port (your local computer). It's optional
* and for logging purpose.
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @warning This function does not bind the local port and does not automatically
* forward the content of a socket to the channel. You still have to
* use channel_read and channel_write for this.
*/
int ssh_channel_open_reverse_forward(ssh_channel channel, const char *remotehost,
int remoteport, const char *sourcehost, int localport) {
ssh_session session;
ssh_buffer payload = NULL;
ssh_string str = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return rc;
}
if(remotehost == NULL || sourcehost == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
session = channel->session;
enter_function();
if(channel->state != SSH_CHANNEL_STATE_NOT_OPEN)
goto pending;
payload = ssh_buffer_new();
if (payload == NULL) {
ssh_set_error_oom(session);
goto error;
}
str = ssh_string_from_char(remotehost);
if (str == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(payload, str) < 0 ||
buffer_add_u32(payload,htonl(remoteport)) < 0) {
ssh_set_error_oom(session);
goto error;
}
ssh_string_free(str);
str = ssh_string_from_char(sourcehost);
if (str == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(payload, str) < 0 ||
buffer_add_u32(payload,htonl(localport)) < 0) {
ssh_set_error_oom(session);
goto error;
}
pending:
rc = channel_open(channel,
"forwarded-tcpip",
CHANNEL_INITIAL_WINDOW,
CHANNEL_MAX_PACKET,
payload);
error:
ssh_buffer_free(payload);
ssh_string_free(str);
leave_function();
return rc;
}
/**
* @brief Open a X11 channel.
*
* @param[in] channel An allocated channel.
*
* @param[in] orig_addr The source host (the local server).
*
* @param[in] orig_port The source port (the local server).
*
* @return SSH_OK on success, SSH_ERROR if an error occured.
*
* @warning This function does not bind the local port and does not automatically
* forward the content of a socket to the channel. You still have to
* use channel_read and channel_write for this.
*/
int ssh_channel_open_x11(ssh_channel channel,
const char *orig_addr, int orig_port) {
ssh_session session;
ssh_buffer payload = NULL;
ssh_string str = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return rc;
}
if(orig_addr == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
session = channel->session;
enter_function();
if(channel->state != SSH_CHANNEL_STATE_NOT_OPEN)
goto pending;
payload = ssh_buffer_new();
if (payload == NULL) {
ssh_set_error_oom(session);
goto error;
}
str = ssh_string_from_char(orig_addr);
if (str == NULL) {
ssh_set_error_oom(session);
goto error;
}
if (buffer_add_ssh_string(payload, str) < 0 ||
buffer_add_u32(payload,htonl(orig_port)) < 0) {
ssh_set_error_oom(session);
goto error;
}
pending:
rc = channel_open(channel,
"x11",
CHANNEL_INITIAL_WINDOW,
CHANNEL_MAX_PACKET,
payload);
error:
ssh_buffer_free(payload);
ssh_string_free(str);
leave_function();
return rc;
}
/**
* @brief Send the exit status to the remote process (as described in RFC 4254, section 6.10).
*
* Sends the exit status to the remote process.
* Only SSH-v2 is supported (I'm not sure about SSH-v1).
*
* @param[in] channel The channel to send exit status.
*
* @param[in] sig The exit status to send
*
* @return SSH_OK on success, SSH_ERROR if an error occured
* (including attempts to send exit status via SSH-v1 session).
*/
int ssh_channel_request_send_exit_status(ssh_channel channel, int exit_status) {
ssh_buffer buffer = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return SSH_ERROR;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
return SSH_ERROR; // TODO: Add support for SSH-v1 if possible.
}
#endif
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_u32(buffer, ntohl(exit_status)) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
rc = channel_request(channel, "exit-status", buffer, 0);
error:
ssh_buffer_free(buffer);
return rc;
}
/**
* @brief Send an exit signal to remote process (as described in RFC 4254, section 6.10).
*
* Sends a signal 'sig' to the remote process.
* Note, that remote system may not support signals concept.
* In such a case this request will be silently ignored.
* Only SSH-v2 is supported (I'm not sure about SSH-v1).
*
* @param[in] channel The channel to send signal.
*
* @param[in] sig The signal to send (without SIG prefix)
* (e.g. "TERM" or "KILL").
* @param[in] core A boolean to tell if a core was dumped
* @param[in] errmsg A CRLF explanation text about the error condition
* @param[in] lang The language used in the message (format: RFC 3066)
*
* @return SSH_OK on success, SSH_ERROR if an error occured
* (including attempts to send signal via SSH-v1 session).
*/
int ssh_channel_request_send_exit_signal(ssh_channel channel, const char *sig,
int core, const char *errmsg, const char *lang) {
ssh_buffer buffer = NULL;
ssh_string tmp = NULL;
int rc = SSH_ERROR;
if(channel == NULL) {
return rc;
}
if(sig == NULL || errmsg == NULL || lang == NULL) {
ssh_set_error_invalid(channel->session, __FUNCTION__);
return rc;
}
#ifdef WITH_SSH1
if (channel->version == 1) {
return SSH_ERROR; // TODO: Add support for SSH-v1 if possible.
}
#endif
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
tmp = ssh_string_from_char(sig);
if (tmp == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, tmp) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_u8(buffer, core?1:0) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
ssh_string_free(tmp);
tmp = ssh_string_from_char(errmsg);
if (tmp == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, tmp) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
ssh_string_free(tmp);
tmp = ssh_string_from_char(lang);
if (tmp == NULL) {
ssh_set_error_oom(channel->session);
goto error;
}
if (buffer_add_ssh_string(buffer, tmp) < 0) {
ssh_set_error_oom(channel->session);
goto error;
}
rc = channel_request(channel, "signal", buffer, 0);
error:
ssh_buffer_free(buffer);
if(tmp)
ssh_string_free(tmp);
return rc;
}
#endif
/* @} */
/* vim: set ts=4 sw=4 et cindent: */
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