view agentfwd.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 a53e7d2d60be
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_AGENTFWD_H_
#define DROPBEAR_AGENTFWD_H_

#include "includes.h"
#include "chansession.h"
#include "channel.h"
#include "auth.h"
#include "list.h"

#if DROPBEAR_CLI_AGENTFWD

/* From OpenSSH authfd.h */
#define SSH_AGENT_RSA_SHA2_256          0x02

/* An agent reply can be reasonably large, as it can
 * contain a list of all public keys held by the agent.
 * 10000 is arbitrary */
#define MAX_AGENT_REPLY  10000

/* client functions */
void cli_load_agent_keys(m_list * ret_list);
void agent_buf_sign(buffer *sigblob, sign_key *key, 
		const buffer *data_buf, enum signature_type type);
void cli_setup_agent(const struct Channel *channel);

#ifdef __hpux
#define seteuid(a)       setresuid(-1, (a), -1)
#define setegid(a)       setresgid(-1, (a), -1)
#endif

extern const struct ChanType cli_chan_agent;

#endif /* DROPBEAR_CLI_AGENTFWD */

#if DROPBEAR_SVR_AGENTFWD

int svr_agentreq(struct ChanSess * chansess);
void svr_agentcleanup(struct ChanSess * chansess);
void svr_agentset(const struct ChanSess *chansess);

#endif /* DROPBEAR_SVR_AGENTFWD */

#endif /* DROPBEAR_AGENTFWD_H_ */