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kftpgrabber
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kftpgrabber/kftpgrabber/src/misc/libs/ssh/channels.c

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/* channels.c */
/* It has support for ... ssh channels */
/*
Copyright 2003 Aris Adamantiadis
This file is part of the SSH Library
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., 51 Franklin Steet, Fifth Floor, Boston,
MA 02110-1301, USA. */
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include "priv.h"
#include "ssh2.h"
#define WINDOWLIMIT 1024
#define WINDOWBASE 32000
static void channel_default_bufferize(CHANNEL *channel, void *data, int len, int is_stderr);
static CHANNEL *new_channel(SSH_SESSION *session){
CHANNEL *channel=malloc(sizeof(CHANNEL));
memset(channel,0,sizeof(CHANNEL));
channel->session=session;
if(!session->channels){
session->channels=channel;
channel->next=channel->prev=channel;
return channel;
}
channel->next=session->channels;
channel->prev=session->channels->prev;
channel->next->prev=channel;
channel->prev->next=channel;
return channel;
}
static u32 channel_new_id(SSH_SESSION *session){
u32 ret=session->maxchannel;
session->maxchannel++;
return ret;
}
static CHANNEL *channel_open(SSH_SESSION *session,char *type_c,int window,
int maxpacket,BUFFER *payload){
CHANNEL *channel=new_channel(session);
STRING *type=string_from_char(type_c);
u32 foo;
int err;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_OPEN);
channel->local_channel=channel_new_id(session);
channel->local_maxpacket=maxpacket;
channel->local_window=window;
ssh_say(2,"creating a channel %d with %d window and %d max packet\n",channel->local_channel,
window,maxpacket);
buffer_add_ssh_string(session->out_buffer,type);
buffer_add_u32(session->out_buffer,htonl(channel->local_channel));
buffer_add_u32(session->out_buffer,htonl(channel->local_window));
buffer_add_u32(session->out_buffer,htonl(channel->local_maxpacket));
free(type);
if(payload)
buffer_add_buffer(session->out_buffer,payload);
packet_send(session);
ssh_say(2,"Sent a SSH_MSG_CHANNEL_OPEN type %s for channel %d\n",type_c,channel->local_channel);
err=packet_wait(session,SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,1);
switch(session->in_packet.type){
case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
buffer_get_u32(session->in_buffer,&foo);
if(channel->local_channel!=ntohl(foo)){
ssh_set_error(session,SSH_INVALID_DATA,"server answered with sender chan num %d instead of given %d",
ntohl(foo),channel->local_channel);
channel_free(channel);
return NULL;
}
buffer_get_u32(session->in_buffer,&foo);
channel->remote_channel=ntohl(foo);
buffer_get_u32(session->in_buffer,&foo);
channel->remote_window=ntohl(foo);
buffer_get_u32(session->in_buffer,&foo);
channel->remote_maxpacket=ntohl(foo);
ssh_say(3,"Received a CHANNEL_OPEN_CONFIRMATION for channel %d:%d\n",
channel->local_channel,channel->remote_channel);
ssh_say(3,"Remote window : %ld, maxpacket : %ld\n",
channel->remote_window, channel->remote_maxpacket);
channel->open=1;
return channel;
case SSH2_MSG_CHANNEL_OPEN_FAILURE:
{
u32 code;
STRING *error_s;
char *error;
buffer_get_u32(session->in_buffer,&foo);
buffer_get_u32(session->in_buffer,&code);
error_s=buffer_get_ssh_string(session->in_buffer);
error=string_to_char(error_s);
ssh_set_error(session,SSH_REQUEST_DENIED,"Channel opening failure : channel %d error (%d) %s",
channel->local_channel,ntohl(code),error);
free(error);
free(error_s);
channel_free(channel);
return NULL;
}
default:
ssh_say(0,"Received unknown packet %d\n",session->in_packet.type);
channel_free(channel);
return NULL;
}
return NULL;
}
static CHANNEL *find_local_channel(SSH_SESSION *session,u32 num){
/* we assume we are always the local */
CHANNEL *initchan,*channel;
initchan=session->channels;
if(!initchan)
return NULL;
for(channel=initchan;channel->local_channel!=num;channel=channel->next){
if(channel->next==initchan)
return NULL;
}
return channel;
}
static void grow_window(SSH_SESSION *session, CHANNEL *channel){
u32 new_window=WINDOWBASE;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_WINDOW_ADJUST);
buffer_add_u32(session->out_buffer,htonl(channel->remote_channel));
buffer_add_u32(session->out_buffer,htonl(new_window));
packet_send(session);
ssh_say(3,"growing window (channel %d:%d) to %d bytes\n",
channel->local_channel,channel->remote_channel,
channel->local_window + new_window);
channel->local_window+=new_window;
}
static CHANNEL *channel_from_msg(SSH_SESSION *session){
u32 chan;
CHANNEL *channel;
if (buffer_get_u32(session->in_buffer,&chan)!=sizeof(u32)){
ssh_set_error(session,SSH_FATAL,"Getting channel from message : short read");
return NULL;
}
channel=find_local_channel(session,ntohl(chan));
if(!channel)
ssh_set_error(session,SSH_FATAL,"Server specified invalid channel %d",ntohl(chan));
return channel;
}
static void channel_rcv_change_window(SSH_SESSION *session){
u32 bytes;
CHANNEL *channel;
int err;
channel=channel_from_msg(session);
if(!channel)
ssh_say(0,"%s\n",ssh_get_error(session));
err = buffer_get_u32(session->in_buffer,&bytes);
if(!channel || err!= sizeof(u32)){
ssh_say(1,"Error getting a window adjust message : invalid packet\n");
return;
}
bytes=ntohl(bytes);
ssh_say(3,"Adding %d bytes to channel (%d:%d) (from %d bytes)\n",bytes,
channel->local_channel,channel->remote_channel,channel->remote_window);
channel->remote_window+=bytes;
}
/* is_stderr is set to 1 if the data are extended, ie stderr */
static void channel_rcv_data(SSH_SESSION *session,int is_stderr){
STRING *str;
CHANNEL *channel;
channel=channel_from_msg(session);
if(!channel){
ssh_say(0,"%s",ssh_get_error(session));
return;
}
if(is_stderr){
u32 ignore;
/* uint32 data type code. we can ignore it */
buffer_get_u32(session->in_buffer,&ignore);
}
str=buffer_get_ssh_string(session->in_buffer);
if(!str){
ssh_say(0,"Invalid data packet !\n");
return;
}
ssh_say(3,"adding %d bytes data in %d\n",string_len(str),is_stderr);
/* what shall we do in this case ? let's accept it anyway */
if(string_len(str)>channel->local_window)
ssh_say(0,"Data packet too big for our window(%d vs %d)",string_len(str),channel->local_window);
if(!is_stderr){
/* stdout */
if(channel->write_fct){
channel->write_fct(channel,str->string,string_len(str),channel->userarg);
} else {
channel_default_bufferize(channel,str->string,string_len(str),is_stderr);
}
} else {
/* stderr */
if(channel->write_err_fct){
channel->write_err_fct(channel,str->string,string_len(str),channel->userarg);
} else {
channel_default_bufferize(channel,str->string,string_len(str),is_stderr);
}
}
if(string_len(str)>=channel->local_window)
channel->local_window-=string_len(str);
else
channel->local_window=0; /* buggy remote */
if(channel->local_window < WINDOWLIMIT)
grow_window(session,channel); /* i wonder if this is the correct place to do that */
free(str);
}
static void channel_rcv_eof(SSH_SESSION *session){
CHANNEL *channel;
channel=channel_from_msg(session);
if(!channel){
ssh_say(0,"%s\n",ssh_get_error(session));
return;
}
ssh_say(2,"Received eof on channel (%d:%d)\n",channel->local_channel,
channel->remote_channel);
/* channel->remote_window=0; */
channel->remote_eof=1;
}
static void channel_rcv_close(SSH_SESSION *session){
CHANNEL *channel;
channel=channel_from_msg(session);
if(!channel){
ssh_say(0,"%s\n",ssh_get_error(session));
return;
}
ssh_say(2,"Received close on channel (%d:%d)\n",channel->local_channel,
channel->remote_channel);
channel->open=0;
if(!channel->remote_eof)
ssh_say(2,"Remote host not polite enough to send an eof before close\n");
channel->remote_eof=1;
}
static void channel_rcv_request(SSH_SESSION *session){
STRING *request_s;
char *request;
u32 status;
CHANNEL *channel=channel_from_msg(session);
if(!channel){
ssh_say(1,"%s\n",ssh_get_error(session));
return;
}
request_s=buffer_get_ssh_string(session->in_buffer);
if(!request_s){
ssh_say(0,"Invalid MSG_CHANNEL_REQUEST\n");
return;
}
buffer_get_u8(session->in_buffer,(u8 *)&status);
request=string_to_char(request_s);
if(!strcmp(request,"exit-status")){
buffer_get_u32(session->in_buffer,&status);
status=ntohl(status);
/* XXX do something with status, we might need it */
free(request_s);
free(request);
return ;
}
if(!strcmp(request,"exit-signal")){
STRING *signal_s;
char *signal;
char *core="(core dumped)";
u8 i;
signal_s=buffer_get_ssh_string(session->in_buffer);
if(!signal_s){
ssh_say(0,"Invalid MSG_CHANNEL_REQUEST\n");
free(request_s);
free(request);
return;
}
signal=string_to_char(signal_s);
buffer_get_u8(session->in_buffer,&i);
if(!i)
core="";
ssh_say(0,"Remote connection closed by signal SIG%s %s\n",signal,core);
free(signal_s);
free(signal);
free(request_s);
free(request);
return;
}
ssh_say(0,"Unknown request %s\n",request);
free(request_s);
free(request);
}
/* channel_handle is called by wait_packet, ie, when there is channel informations to handle . */
void channel_handle(SSH_SESSION *session, int type){
ssh_say(3,"Channel_handle(%d)\n",type);
switch(type){
case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
channel_rcv_change_window(session);
break;
case SSH2_MSG_CHANNEL_DATA:
channel_rcv_data(session,0);
break;
case SSH2_MSG_CHANNEL_EXTENDED_DATA:
channel_rcv_data(session,1);
break;
case SSH2_MSG_CHANNEL_EOF:
channel_rcv_eof(session);
break;
case SSH2_MSG_CHANNEL_CLOSE:
channel_rcv_close(session);
break;
case SSH2_MSG_CHANNEL_REQUEST:
channel_rcv_request(session);
break;
default:
ssh_say(0,"Unexpected message %d\n",type);
}
}
/* 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 */
/* XXX is the window changed ? */
static void channel_default_bufferize(CHANNEL *channel, void *data, int len, int is_stderr){
ssh_say(3,"placing %d bytes into channel buffer (stderr=%d)\n",len,is_stderr);
if(!is_stderr){
/* stdout */
if(!channel->stdout_buffer)
channel->stdout_buffer=buffer_new();
buffer_add_data(channel->stdout_buffer,data,len);
} else {
/* stderr */
if(!channel->stderr_buffer)
channel->stderr_buffer=buffer_new();
buffer_add_data(channel->stderr_buffer,data,len);
}
}
/* --8<-- PUBLIC INTERFACE BEGINS HERE -8<-----8< --- */
/* deprecated */
CHANNEL *open_session_channel(SSH_SESSION *session,int window,int maxpacket){
CHANNEL *chan=channel_open(session,"session",window,maxpacket,NULL);
return chan;
}
CHANNEL *channel_open_session(SSH_SESSION *session){
return open_session_channel(session,64000,32000);
}
/* tcpip forwarding */
CHANNEL *channel_open_forward(SSH_SESSION *session,char *remotehost, int remoteport, char *sourcehost, int localport){
CHANNEL *chan;
BUFFER *payload=buffer_new();
STRING *str=string_from_char(remotehost);
buffer_add_ssh_string(payload,str);
free(str);
str=string_from_char(sourcehost);
buffer_add_u32(payload,htonl(remoteport));
buffer_add_ssh_string(payload,str);
free(str);
buffer_add_u32(payload,htonl(localport));
chan=channel_open(session,"direct-tcpip",64000,32000,payload);
buffer_free(payload);
return chan;
}
void channel_free(CHANNEL *channel){
SSH_SESSION *session=channel->session;
if(session->alive && channel->open)
channel_close(channel);
/* handle the "my channel is first on session list" case */
if(session->channels==channel)
session->channels=channel->next;
/* handle the "my channel is the only on session list" case */
if(channel->next == channel){
session->channels=NULL;
} else {
channel->prev->next=channel->next;
channel->next->prev=channel->prev;
}
if(channel->stdout_buffer)
buffer_free(channel->stdout_buffer);
if(channel->stderr_buffer)
buffer_free(channel->stderr_buffer);
/* debug trick to catch use after frees */
memset(channel,'X',sizeof(CHANNEL));
free(channel);
}
int channel_send_eof(CHANNEL *channel){
SSH_SESSION *session=channel->session;
int ret;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_EOF);
buffer_add_u32(session->out_buffer,htonl(channel->remote_channel));
ret=packet_send(session);
ssh_say(1,"Sent a EOF on client channel (%d:%d)\n",channel->local_channel,
channel->remote_channel);
channel->local_eof=1;
return ret;
}
int channel_close(CHANNEL *channel){
SSH_SESSION *session=channel->session;
int ret=0;
if(!channel->local_eof)
ret=channel_send_eof(channel);
if(ret)
return ret;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_CLOSE);
buffer_add_u32(session->out_buffer,htonl(channel->remote_channel));
ret=packet_send(session);
ssh_say(1,"Sent a close on client channel (%d:%d)\n",channel->local_channel,
channel->remote_channel);
if(!ret)
channel->open =0;
return ret;
}
/* Blocking write */
/* The exact len is written */
int channel_write(CHANNEL *channel ,void *data,int len){
SSH_SESSION *session=channel->session;
int effectivelen;
int origlen=len;
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);
return -1;
}
while(len >0){
if(channel->remote_window<len){
ssh_say(2,"Remote window is %d bytes. going to write %d bytes\n",
channel->remote_window,len);
ssh_say(2,"Waiting for a growing window message...\n");
/* wonder what happens when the channel window is zero */
while(channel->remote_window==0){
/* parse every incoming packet */
packet_wait(channel->session,0,0);
}
effectivelen=len>channel->remote_window?channel->remote_window:len;
} else
effectivelen=len;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_DATA);
buffer_add_u32(session->out_buffer,htonl(channel->remote_channel));
buffer_add_u32(session->out_buffer,htonl(effectivelen));
buffer_add_data(session->out_buffer,data,effectivelen);
packet_send(session);
ssh_say(2,"channel_write wrote %d bytes\n",effectivelen);
channel->remote_window-=effectivelen;
len -= effectivelen;
data+=effectivelen;
}
return origlen;
}
int channel_is_open(CHANNEL *channel){
return (channel->open!=0);
}
static int channel_request(CHANNEL *channel,char *request, BUFFER *buffer,int reply){
STRING *request_s=string_from_char(request);
SSH_SESSION *session=channel->session;
int err;
packet_clear_out(session);
buffer_add_u8(session->out_buffer,SSH2_MSG_CHANNEL_REQUEST);
buffer_add_u32(session->out_buffer,htonl(channel->remote_channel));
buffer_add_ssh_string(session->out_buffer,request_s);
buffer_add_u8(session->out_buffer,reply?1:0);
if(buffer)
buffer_add_data(session->out_buffer,buffer_get(buffer),buffer_get_len(buffer));
packet_send(session);
ssh_say(3,"Sent a SSH_MSG_CHANNEL_REQUEST %s\n",request);
free(request_s);
if(!reply)
return 0;
err=packet_wait(session,SSH2_MSG_CHANNEL_SUCCESS,1);
if(err)
if(session->in_packet.type==SSH2_MSG_CHANNEL_FAILURE){
ssh_say(2,"%s channel request failed\n",request);
ssh_set_error(session,SSH_REQUEST_DENIED,"Channel request %s failed",request);
}
else
ssh_say(3,"Received an unexpected %d message\n",session->in_packet.type);
else
ssh_say(3,"Received a SUCCESS\n");
return err;
}
int channel_request_pty_size(CHANNEL *channel, char *terminal, int col, int row){
STRING *term=string_from_char(terminal);
BUFFER *buffer=buffer_new();
int err;
buffer_add_ssh_string(buffer,term);
buffer_add_u32(buffer,htonl(col));
buffer_add_u32(buffer,htonl(row));
buffer_add_u32(buffer,0);
buffer_add_u32(buffer,0);
/* a 0byte string */
buffer_add_u32(buffer,htonl(1));
buffer_add_u8(buffer,0);
free(term);
err=channel_request(channel,"pty-req",buffer,1);
buffer_free(buffer);
return err;
}
int channel_request_pty(CHANNEL *channel){
return channel_request_pty_size(channel,"xterm",80,24);
}
int channel_change_pty_size(CHANNEL *channel,int cols,int rows){
BUFFER *buffer=buffer_new();
int err;
/*buffer_add_u8(buffer,0);*/
buffer_add_u32(buffer,htonl(cols));
buffer_add_u32(buffer,htonl(rows));
buffer_add_u32(buffer,0);
buffer_add_u32(buffer,0);
err=channel_request(channel,"window-change",buffer,0);
buffer_free(buffer);
return err;
}
int channel_request_shell(CHANNEL *channel){
int err=channel_request(channel,"shell",NULL,1);
return err;
}
int channel_request_subsystem(CHANNEL *channel, char *system){
BUFFER* buffer=buffer_new();
int ret;
STRING *subsystem=string_from_char(system);
buffer_add_ssh_string(buffer,subsystem);
free(subsystem);
ret=channel_request(channel,"subsystem",buffer,1);
buffer_free(buffer);
return ret;
}
int channel_request_sftp( CHANNEL *channel){
return channel_request_subsystem(channel, "sftp");
}
int channel_request_env(CHANNEL *channel,char *name, char *value){
BUFFER *buffer=buffer_new();
int ret;
STRING *string=string_from_char(name);
buffer_add_ssh_string(buffer,string);
free(string);
string=string_from_char(value);
buffer_add_ssh_string(buffer,string);
free(string);
ret=channel_request(channel,"env",buffer,1);
buffer_free(buffer);
return ret;
}
int channel_request_exec(CHANNEL *channel, char *cmd){
BUFFER *buffer=buffer_new();
int ret;
STRING *command=string_from_char(cmd);
buffer_add_ssh_string(buffer,command);
free(command);
ret=channel_request(channel,"exec",buffer,1);
buffer_free(buffer);
return ret;
}
int channel_set_write_handler(CHANNEL *chan,
void (*write_fct)(CHANNEL *channel, void *data, int len, void *userdefined),void *user){
chan->write_fct=write_fct;
chan->userarg=user;
return 0;
}
int channel_set_stderr_write_handler(CHANNEL *chan,
void (*write_err_fct)(CHANNEL *channel, void *data, int len, void *userdefined),void *user){
chan->write_err_fct=write_err_fct;
chan->userarg=user;
return 0;
}
/* reads into a channel and put result into buffer */
/* returns number of bytes read, 0 if eof or such and -1 in case of error */
/* if bytes != 0, the exact number of bytes are going to be read */
int channel_read(CHANNEL *channel, BUFFER *buffer,int bytes,int is_stderr){
BUFFER *stdbuf=NULL;
int len;
buffer_reinit(buffer);
/* maybe i should always set a buffer to avoid races between channel_default_bufferize and channel_read */
if(channel->write_fct){
ssh_set_error(channel->session,SSH_INVALID_REQUEST,"Specified channel hasn't got a default buffering system\n");
return -1;
}
if(is_stderr){
if(!channel->stderr_buffer)
channel->stderr_buffer=buffer_new();
stdbuf=channel->stderr_buffer;
} else {
if(!channel->stdout_buffer)
channel->stdout_buffer=buffer_new();
stdbuf=channel->stdout_buffer;
}
/* block reading if asked bytes=0 */
while((buffer_get_rest_len(stdbuf)==0) || (buffer_get_rest_len(stdbuf) < bytes)){
if(channel->remote_eof && buffer_get_rest_len(stdbuf)==0)
return 0;
if(channel->remote_eof)
break; /* return the resting bytes in buffer */
if(packet_read(channel->session)||packet_translate(channel->session))
return -1;
packet_parse(channel->session);
}
if(bytes==0){
/* write the ful buffer informations */
buffer_add_data(buffer,buffer_get_rest(stdbuf),buffer_get_rest_len(stdbuf));
buffer_reinit(stdbuf);
} else {
len=buffer_get_rest_len(stdbuf);
len= (len>bytes?bytes:len); /* read bytes bytes if len is greater, everything otherwise */
buffer_add_data(buffer,buffer_get_rest(stdbuf),len);
buffer_pass_bytes(stdbuf,len);
}
return buffer_get_len(buffer);
}
/* returns the number of bytes available, 0 if nothing is currently available, -1 if error */
int channel_poll(CHANNEL *channel, int is_stderr){
BUFFER *buffer;
if(is_stderr){
buffer=channel->stderr_buffer;
if(!buffer)
buffer=channel->stderr_buffer=buffer_new();
} else {
buffer=channel->stdout_buffer;
if(!buffer)
buffer=channel->stdout_buffer=buffer_new();
}
while(buffer_get_len(buffer)==0){
if(ssh_fd_poll(channel->session)){
if(packet_read(channel->session)||packet_translate(channel->session))
return -1;
packet_parse(channel->session);
} else
return 0; /* nothing is available has said fd_poll */
}
return buffer_get_len(buffer);
}
/* nonblocking read on the specified channel. it will return <=len bytes of data read
atomicly. */
int channel_read_nonblocking(CHANNEL *channel, char *dest, int len, int is_stderr){
int to_read=channel_poll(channel,is_stderr);
int lu;
BUFFER *buffer=buffer_new();
if(to_read<=0){
buffer_free(buffer);
return to_read; /* may be an error code */
}
if(to_read>len)
to_read=len;
lu=channel_read(channel,buffer,to_read,is_stderr);
memcpy(dest,buffer_get(buffer),lu>=0?lu:0);
buffer_free(buffer);
return lu;
}
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