/* 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. ******************************************************************/ #ifndef DROPBEAR_DEFPORT #define DROPBEAR_DEFPORT "22" #endif #ifndef DROPBEAR_DEFADDRESS /* Listen on all interfaces */ #define DROPBEAR_DEFADDRESS "" #endif /* Default hostkey paths - these can be specified on the command line */ #ifndef DSS_PRIV_FILENAME #define DSS_PRIV_FILENAME "/etc/dropbear/dropbear_dss_host_key" #endif #ifndef RSA_PRIV_FILENAME #define RSA_PRIV_FILENAME "/etc/dropbear/dropbear_rsa_host_key" #endif /* 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 NON_INETD_MODE #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 (AES, DES etc) slower (perhaps by 50%). Recommended for most small systems. */ #define DROPBEAR_SMALL_CODE /* 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) */ #define ENABLE_CLI_LOCALTCPFWD #define ENABLE_CLI_REMOTETCPFWD #define ENABLE_SVR_LOCALTCPFWD #define ENABLE_SVR_REMOTETCPFWD /* Enable Authentication Agent Forwarding - server only for now */ #define ENABLE_AGENTFWD /* Encryption - at least one required. * RFC Draft 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_CBC #define DROPBEAR_3DES_CBC #define DROPBEAR_AES256_CBC #define DROPBEAR_BLOWFISH_CBC #define DROPBEAR_TWOFISH256_CBC #define DROPBEAR_TWOFISH128_CBC /* Message Integrity - at least one required. * RFC Draft requires sha1 and recommends sha1-96. * sha1-96 may be of use for slow links, as it has a smaller overhead. * * Note: there's no point disabling sha1 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_SHA1_HMAC #define DROPBEAR_SHA1_96_HMAC #define DROPBEAR_MD5_HMAC /* 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 */ #define DROPBEAR_RSA #define DROPBEAR_DSS /* RSA can be vulnerable to timing attacks which use the time required for * signing to guess the private key. Blinding avoids this attack, though makes * signing operations slightly slower. */ #define RSA_BLINDING /* Define DSS_PROTOK to use PuTTY's method of generating the value k for dss, * rather than just from the random byte source. Undefining this will save you * ~4k in binary size with static uclibc, but your DSS hostkey could be exposed * if the random number source isn't good. In general this isn't required */ /* #define DSS_PROTOK */ /* 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 */ #ifndef MOTD_FILENAME #define MOTD_FILENAME "/etc/motd" #endif /* 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 - don't bother using it otherwise. * You can't enable both PASSWORD and PAM. */ #define ENABLE_SVR_PASSWORD_AUTH /*#define ENABLE_SVR_PAM_AUTH */ /* requires ./configure --enable-pam */ #define ENABLE_SVR_PUBKEY_AUTH #define ENABLE_CLI_PASSWORD_AUTH #define ENABLE_CLI_PUBKEY_AUTH #define ENABLE_CLI_INTERACT_AUTH /* 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 DROPBEAR_PASSWORD_ENV "DROPBEAR_PASSWORD" /* 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 */ /*#define ENABLE_CLI_ASKPASS_HELPER*/ /* Random device to use - define either DROPBEAR_RANDOM_DEV or * DROPBEAR_PRNGD_SOCKET. * DROPBEAR_RANDOM_DEV is recommended on hosts with a good /dev/(u)random, * otherwise use run prngd (or egd if you want), specifying the socket. * The device will be queried for a few dozen bytes of seed a couple of times * per session (or more for very long-lived sessions). */ /* We'll use /dev/urandom by default, since /dev/random is too much hassle. * If system developers aren't keeping seeds between boots nor getting * any entropy from somewhere it's their own fault. */ #define DROPBEAR_RANDOM_DEV "/dev/urandom" /* prngd must be manually set up to produce output */ /*#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 */ #ifndef MAX_UNAUTH_PER_IP #define MAX_UNAUTH_PER_IP 5 #endif /* And then a global limit to avoid chewing memory if connections * come from many IPs */ #ifndef MAX_UNAUTH_CLIENTS #define MAX_UNAUTH_CLIENTS 30 #endif /* Maximum number of failed authentication tries (server option) */ #ifndef MAX_AUTH_TRIES #define MAX_AUTH_TRIES 10 #endif /* The default file to store the daemon's process ID, for shutdown scripts etc. This can be overridden with the -P flag */ #ifndef DROPBEAR_PIDFILE #define DROPBEAR_PIDFILE "/var/run/dropbear.pid" #endif /* The command to invoke for xauth when using X11 forwarding. * "-q" for quiet */ #ifndef XAUTH_COMMAND #define XAUTH_COMMAND "/usr/X11R6/bin/xauth -q" #endif /* 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 */ #ifndef SFTPSERVER_PATH #define SFTPSERVER_PATH "/usr/libexec/sftp-server" #endif /* 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. */ #define DEFAULT_RECV_WINDOW 24576 /* 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. */ #define TRANS_MAX_PAYLOAD_LEN 16384 /* Ensure that data is transmitted every KEEPALIVE seconds. This can be overridden at runtime with -K. 0 disables keepalives */ #define DEFAULT_KEEPALIVE 0 /******************************************************************* * You shouldn't edit below here unless you know you need to. *******************************************************************/ #ifndef DROPBEAR_VERSION #define DROPBEAR_VERSION "0.50" #endif #define LOCAL_IDENT "SSH-2.0-dropbear_" DROPBEAR_VERSION #define PROGNAME "dropbear" /* Spec recommends after one hour or 1 gigabyte of data. One hour * is a bit too verbose, so we try 8 hours */ #ifndef KEX_REKEY_TIMEOUT #define KEX_REKEY_TIMEOUT (3600 * 8) #endif #ifndef KEX_REKEY_DATA #define KEX_REKEY_DATA (1<<30) /* 2^30 == 1GB, this value must be < INT_MAX */ #endif /* Close connections to clients which haven't authorised after AUTH_TIMEOUT */ #ifndef AUTH_TIMEOUT #define AUTH_TIMEOUT 300 /* we choose 5 minutes */ #endif /* Minimum key sizes for DSS and RSA */ #ifndef MIN_DSS_KEYLEN #define MIN_DSS_KEYLEN 512 #endif #ifndef MIN_RSA_KEYLEN #define MIN_RSA_KEYLEN 512 #endif #define MAX_BANNER_SIZE 2000 /* this is 25*80 chars, any more is foolish */ #define MAX_BANNER_LINES 20 /* How many lines the client will display */ /* the number of NAME=VALUE pairs to malloc for environ, if we don't have * the clearenv() function */ #define ENV_SIZE 100 #define MAX_CMD_LEN 1024 /* max length of a command */ #define MAX_TERM_LEN 200 /* max length of TERM name */ #define MAX_HOST_LEN 254 /* max hostname len for tcp fwding */ #define MAX_IP_LEN 15 /* strlen("255.255.255.255") == 15 */ #define DROPBEAR_MAX_PORTS 10 /* max number of ports which can be specified, ipv4 and ipv6 don't count twice */ /* Each port might have at least a v4 and a v6 address */ #define MAX_LISTEN_ADDR (DROPBEAR_MAX_PORTS*3) #define _PATH_TTY "/dev/tty" #define _PATH_CP "/bin/cp" /* success/failure defines */ #define DROPBEAR_SUCCESS 0 #define DROPBEAR_FAILURE -1 /* various algorithm identifiers */ #define DROPBEAR_KEX_DH_GROUP1 0 #define DROPBEAR_SIGNKEY_ANY 0 #define DROPBEAR_SIGNKEY_RSA 1 #define DROPBEAR_SIGNKEY_DSS 2 #define DROPBEAR_SIGNKEY_NONE 3 #define DROPBEAR_COMP_NONE 0 #define DROPBEAR_COMP_ZLIB 1 /* Required for pubkey auth */ #if defined(ENABLE_SVR_PUBKEY_AUTH) || defined(DROPBEAR_CLIENT) #define DROPBEAR_SIGNKEY_VERIFY #endif /* SHA1 is 20 bytes == 160 bits */ #define SHA1_HASH_SIZE 20 /* SHA512 is 64 bytes == 512 bits */ #define SHA512_HASH_SIZE 64 /* MD5 is 16 bytes = 128 bits */ #define MD5_HASH_SIZE 16 /* largest of MD5 and SHA1 */ #define MAX_MAC_LEN SHA1_HASH_SIZE #define MAX_KEY_LEN 32 /* 256 bits for aes256 etc */ #define MAX_IV_LEN 20 /* must be same as max blocksize, and >= SHA1_HASH_SIZE */ #define MAX_MAC_KEY 20 #define MAX_NAME_LEN 64 /* maximum length of a protocol name, isn't explicitly specified for all protocols (just for algos) but seems valid */ #define MAX_PROPOSED_ALGO 20 /* size/count limits */ #define MIN_PACKET_LEN 16 #define RECV_MAX_PACKET_LEN (MAX(35000, ((RECV_MAX_PAYLOAD_LEN)+100))) /* for channel code */ #define TRANS_MAX_WINDOW 500000000 /* 500MB is sufficient, stopping overflow */ #define TRANS_MAX_WIN_INCR 500000000 /* overflow prevention */ #define RECV_WINDOWEXTEND (opts.recv_window / 3) /* We send a "window extend" every RECV_WINDOWEXTEND bytes */ #define MAX_RECV_WINDOW (1024*1024) /* 1 MB should be enough */ #define MAX_CHANNELS 100 /* simple mem restriction, includes each tcp/x11 connection, so can't be _too_ small */ #define MAX_STRING_LEN 1400 /* ~= MAX_PROPOSED_ALGO * MAX_NAME_LEN, also is the max length for a password etc */ /* For a 4096 bit DSS key, empirically determined */ #define MAX_PUBKEY_SIZE 1700 /* For a 4096 bit DSS key, empirically determined */ #define MAX_PRIVKEY_SIZE 1700 /* The maximum size of the bignum portion of the kexhash buffer */ /* Sect. 8 of the transport draft, K_S + e + f + K */ #define KEXHASHBUF_MAX_INTS (1700 + 130 + 130 + 130) #define DROPBEAR_MAX_SOCKS 2 /* IPv4, IPv6 are all we'll get for now. Revisit in a few years time.... */ #define DROPBEAR_MAX_CLI_PASS 1024 #define DROPBEAR_MAX_CLI_INTERACT_PROMPTS 80 /* The number of prompts we'll accept for keyb-interactive auth */ #if defined(DROPBEAR_AES256_CBC) || defined(DROPBEAR_AES128_CBC) #define DROPBEAR_AES_CBC #endif #if defined(DROPBEAR_TWOFISH256_CBC) || defined(DROPBEAR_TWOFISH128_CBC) #define DROPBEAR_TWOFISH_CBC #endif #ifndef ENABLE_X11FWD #define DISABLE_X11FWD #endif #ifndef ENABLE_AGENTFWD #define DISABLE_AGENTFWD #endif #if defined(ENABLE_CLI_REMOTETCPFWD) || defined(ENABLE_CLI_LOCALTCPFWD) #define ENABLE_CLI_ANYTCPFWD #endif #if defined(ENABLE_CLI_LOCALTCPFWD) || defined(ENABLE_SVR_REMOTETCPFWD) #define DROPBEAR_TCP_ACCEPT #endif #if defined(ENABLE_CLI_REMOTETCPFWD) || defined(ENABLE_CLI_LOCALTCPFWD) || \ defined(ENABLE_SVR_REMOTETCPFWD) || defined(ENABLE_SVR_LOCALTCPFWD) || \ defined(ENABLE_AGENTFWD) || defined(ENABLE_X11FWD) #define USING_LISTENERS #endif #if defined(DROPBEAR_CLIENT) || defined(ENABLE_SVR_PUBKEY_AUTH) #define DROPBEAR_KEY_LINES /* ie we're using authorized_keys or known_hosts */ #endif #if defined(ENABLE_SVR_PASSWORD_AUTH) && defined(ENABLE_SVR_PAM_AUTH) #error "You can't turn on PASSWORD and PAM auth both at once. Fix it in options.h" #endif #if defined(DROPBEAR_RANDOM_DEV) && defined(DROPBEAR_PRNGD_SOCKET) #error "You can't turn on DROPBEAR_PRNGD_SOCKET and DROPBEAR_RANDOM_DEV at once" #endif #if !defined(DROPBEAR_RANDOM_DEV) && !defined(DROPBEAR_PRNGD_SOCKET) #error "You must choose one of DROPBEAR_PRNGD_SOCKET or DROPBEAR_RANDOM_DEV in options.h" #endif /* We use dropbear_client and dropbear_server as shortcuts to avoid redundant * code, if we're just compiling as client or server */ #if defined(DROPBEAR_SERVER) && defined(DROPBEAR_CLIENT) #define IS_DROPBEAR_SERVER (ses.isserver == 1) #define IS_DROPBEAR_CLIENT (ses.isserver == 0) #elif defined(DROPBEAR_SERVER) #define IS_DROPBEAR_SERVER 1 #define IS_DROPBEAR_CLIENT 0 #elif defined(DROPBEAR_CLIENT) #define IS_DROPBEAR_SERVER 0 #define IS_DROPBEAR_CLIENT 1 #else #error You must compiled with either DROPBEAR_CLIENT or DROPBEAR_SERVER selected #endif #endif /* _OPTIONS_H_ */