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/* Dropbear SSH
* Copyright (c) 2002,2003 Matt Johnston
* All rights reserved. See LICENSE for the license. */
#ifndef _OPTIONS_H_
#define _OPTIONS_H_
/* Define compile-time options below - the "#ifndef DROPBEAR_XXX .... #endif"
* parts are to allow for commandline -DDROPBEAR_XXX options etc. */
/* IMPORTANT: Many options will require "make clean" after changes */
/* Listen on all interfaces */
/* Default hostkey paths - these can be specified on the command line */
#define DSS_PRIV_FILENAME "/etc/dropbear/dropbear_dss_host_key"
#define RSA_PRIV_FILENAME "/etc/dropbear/dropbear_rsa_host_key"
#define ECDSA_PRIV_FILENAME "/etc/dropbear/dropbear_ecdsa_host_key"
/* Set NON_INETD_MODE if you require daemon functionality (ie Dropbear listens
* on chosen ports and keeps accepting connections. This is the default.
* Set INETD_MODE if you want to be able to run Dropbear with inetd (or
* similar), where it will use stdin/stdout for connections, and each process
* lasts for a single connection. Dropbear should be invoked with the -i flag
* for inetd, and can only accept IPv4 connections.
* Both of these flags can be defined at once, don't compile without at least
* one of them. */
#define INETD_MODE
/* Setting this disables the fast exptmod bignum code. It saves ~5kB, but is
* perhaps 20% slower for pubkey operations (it is probably worth experimenting
* if you want to use this) */
/*#define NO_FAST_EXPTMOD*/
/* Set this if you want to use the DROPBEAR_SMALL_CODE option. This can save
several kB in binary size however will make the symmetrical ciphers and hashes
slower, perhaps by 50%. Recommended for small systems that aren't doing
much traffic. */
/* Enable X11 Forwarding - server only */
#define ENABLE_X11FWD
/* Enable TCP Fowarding */
/* 'Local' is "-L" style (client listening port forwarded via server)
* 'Remote' is "-R" style (server listening port forwarded via client) */
/* Enable Authentication Agent Forwarding */
/* Note: Both ENABLE_CLI_PROXYCMD and ENABLE_CLI_NETCAT must be set to
* allow multihop dbclient connections */
/* Allow using -J <proxycommand> to run the connection through a
pipe to a program, rather the normal TCP connection */
/* Enable "Netcat mode" option. This will forward standard input/output
* to a remote TCP-forwarded connection */
/* Whether to support "-c" and "-m" flags to choose ciphers/MACs at runtime */
/* Encryption - at least one required.
* Protocol RFC requires 3DES and recommends AES128 for interoperability.
* Including multiple keysize variants the same cipher
* (eg AES256 as well as AES128) will result in a minimal size increase.*/
#define DROPBEAR_AES128
#define DROPBEAR_AES256
/* Compiling in Blowfish will add ~6kB to runtime heap memory usage */
/* Enable "Counter Mode" for ciphers. This is more secure than normal
* CBC mode against certain attacks. This adds around 1kB to binary
* size and is recommended for most cases */
/* You can compile with no encryption if you want. In some circumstances
* this could be safe security-wise, though make sure you know what
* you're doing. Anyone can see everything that goes over the wire, so
* the only safe auth method is public key. */
/* Message Integrity - at least one required.
* Protocol RFC requires sha1 and recommends sha1-96.
* sha1-96 is of use for slow links as it has a smaller overhead.
* There's no reason to disable sha1 or sha1-96 to save space since it's
* used for the random number generator and public-key cryptography anyway.
* Disabling it here will just stop it from being used as the integrity portion
* of the ssh protocol.
* These hashes are also used for public key fingerprints in logs.
* If you disable MD5, Dropbear will fall back to SHA1 fingerprints,
* which are not the standard form. */
/*#define DROPBEAR_SHA2_256_HMAC*/
/*#define DROPBEAR_SHA2_512_HMAC*/
/* You can also disable integrity. Don't bother disabling this if you're
* still using a cipher, it's relatively cheap. If you disable this it's dead
* simple for an attacker to run arbitrary commands on the remote host. Beware. */
/* Hostkey/public key algorithms - at least one required, these are used
* for hostkey as well as for verifying signatures with pubkey auth.
* Removing either of these won't save very much space.
* SSH2 RFC Draft requires dss, recommends rsa */
/* ECDSA is significantly faster than RSA or DSS. Compiling in ECC
* code (either ECDSA or ECDH) increases binary size - around 30kB
* on x86-64 */
/* Generate hostkeys as-needed when the first connection using that key type occurs.
This avoids the need to otherwise run "dropbearkey" and avoids some problems
with badly seeded /dev/urandom when systems first boot.
This also requires a runtime flag "-R". This adds ~4kB to binary size (or hardly
anything if dropbearkey is linked in a "dropbearmulti" binary) */
/* Enable Curve25519 for key exchange. This is another elliptic
* curve method with good security properties. Increases binary size
* by ~8kB on x86-64 */
#define DROPBEAR_CURVE25519
/* Enable elliptic curve Diffie Hellman key exchange, see note about
* ECDSA above */
/* Control the memory/performance/compression tradeoff for zlib.
* Set windowBits=8 for least memory usage, see your system's
* zlib.h for full details.
* Default settings (windowBits=15) will use 256kB for compression
* windowBits=8 will use 129kB for compression.
* Both modes will use ~35kB for decompression (using windowBits=15 for
* interoperability) */
/* Whether to do reverse DNS lookups. */
/*#define DO_HOST_LOOKUP */
/* Whether to print the message of the day (MOTD). This doesn't add much code
* size */
#define DO_MOTD
/* The MOTD file path */
#define MOTD_FILENAME "/etc/motd"
/* Authentication Types - at least one required.
RFC Draft requires pubkey auth, and recommends password */
/* Note: PAM auth is quite simple and only works for PAM modules which just do
* a simple "Login: " "Password: " (you can edit the strings in svr-authpam.c).
* It's useful for systems like OS X where standard password crypts don't work
* but there's an interface via a PAM module. It won't work for more complex
* PAM challenge/response.
* You can't enable both PASSWORD and PAM. */
/* PAM requires ./configure --enable-pam */
/*#define ENABLE_SVR_PAM_AUTH */
/* Whether to take public key options in
* authorized_keys file into account */
/* This variable can be used to set a password for client
* authentication on the commandline. Beware of platforms
* that don't protect environment variables of processes etc. Also
* note that it will be provided for all "hidden" client-interactive
* style prompts - if you want something more sophisticated, use
* SSH_ASKPASS instead. Comment out this var to remove this functionality.*/
/* Define this (as well as ENABLE_CLI_PASSWORD_AUTH) to allow the use of
* a helper program for the ssh client. The helper program should be
* specified in the SSH_ASKPASS environment variable, and dbclient
* should be run with DISPLAY set and no tty. The program should
* return the password on standard output */
/* Save a network roundtrip by sendng a real auth request immediately after
* sending a query for the available methods. It is at the expense of < 100
* bytes of extra network traffic. This is not yet enabled by default since it
* could cause problems with non-compliant servers */
/* Source for randomness. This must be able to provide hundreds of bytes per SSH
* connection without blocking. In addition /dev/random is used for seeding
* rsa/dss key generation */
#define DROPBEAR_URANDOM_DEV "/dev/urandom"
/* Set this to use PRNGD or EGD instead of /dev/urandom or /dev/random */
/*#define DROPBEAR_PRNGD_SOCKET "/var/run/dropbear-rng"*/
/* Specify the number of clients we will allow to be connected but
* not yet authenticated. After this limit, connections are rejected */
/* The first setting is per-IP, to avoid denial of service */
/* And then a global limit to avoid chewing memory if connections
* come from many IPs */
/* Maximum number of failed authentication tries (server option) */
#define MAX_AUTH_TRIES 10
/* The default file to store the daemon's process ID, for shutdown
scripts etc. This can be overridden with the -P flag */
#define DROPBEAR_PIDFILE "/var/run/"
/* The command to invoke for xauth when using X11 forwarding.
* "-q" for quiet */
#define XAUTH_COMMAND "/usr/bin/X11/xauth -q"
/* if you want to enable running an sftp server (such as the one included with
* OpenSSH), set the path below. If the path isn't defined, sftp will not
* be enabled */
#define SFTPSERVER_PATH "/usr/libexec/sftp-server"
/* This is used by the scp binary when used as a client binary. If you're
* not using the Dropbear client, you'll need to change it */
#define _PATH_SSH_PROGRAM "/usr/bin/dbclient"
/* Whether to log commands executed by a client. This only logs the
* (single) command sent to the server, not what a user did in a
* shell/sftp session etc. */
/* #define LOG_COMMANDS */
/* Window size limits. These tend to be a trade-off between memory
usage and network performance: */
/* Size of the network receive window. This amount of memory is allocated
as a per-channel receive buffer. Increasing this value can make a
significant difference to network performance. 24kB was empirically
chosen for a 100mbit ethernet network. The value can be altered at
runtime with the -W argument. */
/* Maximum size of a received SSH data packet - this _MUST_ be >= 32768
in order to interoperate with other implementations */
#define RECV_MAX_PAYLOAD_LEN 32768
/* Maximum size of a transmitted data packet - this can be any value,
though increasing it may not make a significant difference. */
/* Ensure that data is transmitted every KEEPALIVE seconds. This can
be overridden at runtime with -K. 0 disables keepalives */
/* If this many KEEPALIVES are sent with no packets received from the
other side, exit. Not run-time configurable - if you have a need
for runtime configuration please mail the Dropbear list */
/* Ensure that data is received within IDLE_TIMEOUT seconds. This can
be overridden at runtime with -I. 0 disables idle timeouts */
/* The default path. This will often get replaced by the shell */
#define DEFAULT_PATH "/usr/bin:/bin"
/* Some other defines (that mostly should be left alone) are defined
* in sysoptions.h */
#include "sysoptions.h"
#endif /* _OPTIONS_H_ */