view chansession.h @ 1715:3974f087d9c0

Disallow leading lines before the ident for server (#102) Per RFC4253 4.2 clients must be able to process other lines of data before the version string, server behavior is not defined neither with MUST/SHOULD nor with MAY. If server process up to 50 lines too - it may cause too long hanging session with invalid/evil client that consume host resources and potentially may lead to DDoS on poor embedded boxes. Let's require first line from client to be version string and fail early if it's not - matches both RFC and real OpenSSH behavior.
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Mon, 15 Jun 2020 18:22:18 +0500
parents 8a7d26e86a56
children
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/*
 * Dropbear - a SSH2 server
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE. */

#ifndef DROPBEAR_CHANSESSION_H_
#define DROPBEAR_CHANSESSION_H_

#include "loginrec.h"
#include "channel.h"
#include "listener.h"

struct exitinfo {

	int exitpid; /* -1 if not exited */
	int exitstatus;
	int exitsignal;
	int exitcore;
};

struct ChanSess {

	char * cmd; /* command to exec */
	pid_t pid; /* child process pid */
	/* command that was sent by the client, if authorized_keys command= or
	dropbear -c was used */
	char *original_command;

	/* pty details */
	int master; /* the master terminal fd*/
	int slave;
	char * tty;
	char * term;

	/* exit details */
	struct exitinfo exit;


	/* These are only set temporarily before forking */
	/* Used to set $SSH_CONNECTION in the child session.  */
	char *connection_string;
	/* Used to set $SSH_CLIENT in the child session. */
	char *client_string;
	
#if DROPBEAR_X11FWD
	struct Listener * x11listener;
	int x11port;
	char * x11authprot;
	char * x11authcookie;
	unsigned int x11screennum;
	unsigned char x11singleconn;
#endif

#if DROPBEAR_SVR_AGENTFWD
	struct Listener * agentlistener;
	char * agentfile;
	char * agentdir;
#endif
};

struct ChildPid {
	pid_t pid;
	struct ChanSess * chansess;
};


void addnewvar(const char* param, const char* var);

void cli_send_chansess_request(void);
void cli_tty_cleanup(void);
void cli_chansess_winchange(void);
#if DROPBEAR_CLI_NETCAT
void cli_send_netcat_request(void);
#endif

void svr_chansessinitialise(void);
void svr_chansess_checksignal(void);
extern const struct ChanType svrchansess;

struct SigMap {
	int signal;
	char* name;
};

extern const struct SigMap signames[];

#endif /* DROPBEAR_CHANSESSION_H_ */