view chansession.h @ 1930:299f4f19ba19

Add /usr/sbin and /sbin to default root PATH When dropbear is used in a very restricted environment (such as in a initrd), the default user shell is often also very restricted and doesn't take care of setting the PATH so the user ends up with the PATH set by dropbear. Unfortunately, dropbear always sets "/usr/bin:/bin" as default PATH even for the root user which should have /usr/sbin and /sbin too. For a concrete instance of this problem, see the "Remote Unlocking" section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/ It speaks of a bug in the initramfs script because it's written "blkid" instead of "/sbin/blkid"... this is just because the scripts from the initramfs do not expect to have a PATH without the sbin directories and because dropbear is not setting the PATH appropriately for the root user. I'm thus suggesting to use the attached patch to fix this misbehaviour (I did not test it, but it's easy enough). It might seem anecdotic but multiple Kali users have been bitten by this. From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
author Raphael Hertzog <hertzog@debian.org>
date Mon, 09 Jul 2018 16:27:53 +0200
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_ */