Mercurial > dropbear
view sysoptions.h @ 1916:3f4cdf839a1a
Make SHA1 optional, implement SHA256 fingerprints
SHA256 is always compiled and only enable SHA1 when needed. Fingerprints
are always SHA256: base64 format, md5 and sha1 are removed. dbrandom now
uses sha256 its hash function.
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Wed, 30 Mar 2022 11:44:04 +0800 |
parents | 13cb8cc1b0e4 |
children | 77bc00dcc19f |
line wrap: on
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/******************************************************************* * You shouldn't edit this file unless you know you need to. * This file is only included from options.h *******************************************************************/ #ifndef DROPBEAR_VERSION #define DROPBEAR_VERSION "2020.81" #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 #define DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT ((DROPBEAR_SVR_PUBKEY_AUTH) && (DROPBEAR_SVR_PUBKEY_OPTIONS)) #if !(NON_INETD_MODE || INETD_MODE) #error "NON_INETD_MODE or INETD_MODE (or both) must be enabled." #endif /* Would probably work on freebsd but hasn't been tested */ #if defined(HAVE_FEXECVE) && DROPBEAR_REEXEC && defined(__linux__) #define DROPBEAR_DO_REEXEC 1 #else #define DROPBEAR_DO_REEXEC 0 #endif /* A client should try and send an initial key exchange packet guessing * the algorithm that will match - saves a round trip connecting, has little * overhead if the guess was "wrong". */ #ifndef DROPBEAR_KEX_FIRST_FOLLOWS #define DROPBEAR_KEX_FIRST_FOLLOWS 1 #endif /* Use protocol extension to allow "first follows" to succeed more frequently. * This is currently Dropbear-specific but will gracefully fallback when connecting * to other implementations. */ #ifndef DROPBEAR_KEXGUESS2 #define DROPBEAR_KEXGUESS2 1 #endif /* Minimum key sizes for DSS and RSA */ #ifndef MIN_DSS_KEYLEN #define MIN_DSS_KEYLEN 1024 #endif #ifndef MIN_RSA_KEYLEN #define MIN_RSA_KEYLEN 1024 #endif #define MAX_BANNER_SIZE 2050 /* 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 9000 /* 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" #define DROPBEAR_ESCAPE_CHAR '~' /* success/failure defines */ #define DROPBEAR_SUCCESS 0 #define DROPBEAR_FAILURE -1 #define DROPBEAR_PASSWORD_ENV "DROPBEAR_PASSWORD" #define DROPBEAR_NGROUP_MAX 1024 /* Required for pubkey auth */ #define DROPBEAR_SIGNKEY_VERIFY ((DROPBEAR_SVR_PUBKEY_AUTH) || (DROPBEAR_CLIENT)) /* crypt(password) must take less time than the auth failure delay (250ms set in svr-auth.c). On Linux the delay depends on password length, 100 characters here was empirically derived. If a longer password is allowed Dropbear cannot compensate for the crypt time which will expose which usernames exist */ #define DROPBEAR_MAX_PASSWORD_LEN 100 #define SHA1_HASH_SIZE 20 #define SHA256_HASH_SIZE 32 #define MD5_HASH_SIZE 16 #define MAX_HASH_SIZE 64 /* sha512 */ #if DROPBEAR_CHACHA20POLY1305 #define MAX_KEY_LEN 64 /* 2 x 256 bits for chacha20 */ #else #define MAX_KEY_LEN 32 /* 256 bits for aes256 etc */ #endif #define MAX_IV_LEN 20 /* must be same as max blocksize, */ #if DROPBEAR_SHA2_512_HMAC #define MAX_MAC_LEN 64 #elif DROPBEAR_SHA2_256_HMAC #define MAX_MAC_LEN 32 #else #define MAX_MAC_LEN 20 #endif /* sha2-512 is not necessary unless unforseen problems arise with sha2-256 */ #ifndef DROPBEAR_SHA2_512_HMAC #define DROPBEAR_SHA2_512_HMAC 0 #endif /* might be needed for compatibility with very old implementations */ #ifndef DROPBEAR_MD5_HMAC #define DROPBEAR_MD5_HMAC 0 #endif #define DROPBEAR_ECC ((DROPBEAR_ECDH) || (DROPBEAR_ECDSA)) /* Debian doesn't define this in system headers */ #if !defined(LTM_DESC) && (DROPBEAR_ECC) #define LTM_DESC #endif #define DROPBEAR_ECC_256 (DROPBEAR_ECC) #define DROPBEAR_ECC_384 (DROPBEAR_ECC) #define DROPBEAR_ECC_521 (DROPBEAR_ECC) #define DROPBEAR_LTC_PRNG (DROPBEAR_ECC) /* 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 DROPBEAR_RSA_BLINDING 1 #ifndef DROPBEAR_RSA_SHA1 #define DROPBEAR_RSA_SHA1 DROPBEAR_RSA #endif #ifndef DROPBEAR_RSA_SHA256 #define DROPBEAR_RSA_SHA256 DROPBEAR_RSA #endif /* hashes which will be linked and registered */ #define DROPBEAR_SHA1 (DROPBEAR_RSA_SHA1 || DROPBEAR_DSS \ || DROPBEAR_SHA1_HMAC || DROPBEAR_SHA1_96_HMAC \ || DROPBEAR_DH_GROUP1 || DROPBEAR_DH_GROUP14_SHA1 ) /* sha256 is always used for fingerprints and dbrandom */ #define DROPBEAR_SHA256 1 #define DROPBEAR_SHA384 (DROPBEAR_ECC_384) /* LTC SHA384 depends on SHA512 */ #define DROPBEAR_SHA512 ((DROPBEAR_SHA2_512_HMAC) || (DROPBEAR_ECC_521) \ || (DROPBEAR_SHA384) || (DROPBEAR_DH_GROUP16) \ || (DROPBEAR_ED25519)) #define DROPBEAR_MD5 (DROPBEAR_MD5_HMAC) #define DROPBEAR_DH_GROUP14 ((DROPBEAR_DH_GROUP14_SHA256) || (DROPBEAR_DH_GROUP14_SHA1)) #define DROPBEAR_NORMAL_DH ((DROPBEAR_DH_GROUP1) || (DROPBEAR_DH_GROUP14) || (DROPBEAR_DH_GROUP16)) /* Dropbear only uses server-sig-algs, only needed if we have rsa-sha256 pubkey auth */ #define DROPBEAR_EXT_INFO ((DROPBEAR_RSA_SHA256) \ && ((DROPBEAR_CLI_PUBKEY_AUTH) || (DROPBEAR_SVR_PUBKEY_AUTH))) /* roughly 2x 521 bits */ #define MAX_ECC_SIZE 140 #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 50 /* size/count limits */ /* From transport rfc */ #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 (10*1024*1024) /* 10 MB should be enough */ #define MAX_CHANNELS 1000 /* simple mem restriction, includes each tcp/x11 connection, so can't be _too_ small */ #define MAX_STRING_LEN (MAX(MAX_CMD_LEN, 2400)) /* Sun SSH needs 2400 for algos, MAX_CMD_LEN is usually longer */ /* 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 #define MAX_HOSTKEYS 4 /* The maximum size of the bignum portion of the kexhash buffer */ /* Sect. 8 of the transport rfc 4253, 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 */ #define DROPBEAR_AES ((DROPBEAR_AES256) || (DROPBEAR_AES128)) #define DROPBEAR_AEAD_MODE ((DROPBEAR_CHACHA20POLY1305) || (DROPBEAR_ENABLE_GCM_MODE)) #define DROPBEAR_CLI_ANYTCPFWD ((DROPBEAR_CLI_REMOTETCPFWD) || (DROPBEAR_CLI_LOCALTCPFWD)) #define DROPBEAR_TCP_ACCEPT ((DROPBEAR_CLI_LOCALTCPFWD) || (DROPBEAR_SVR_REMOTETCPFWD)) #define DROPBEAR_LISTENERS \ ((DROPBEAR_CLI_REMOTETCPFWD) || (DROPBEAR_CLI_LOCALTCPFWD) || \ (DROPBEAR_SVR_REMOTETCPFWD) || (DROPBEAR_SVR_LOCALTCPFWD) || \ (DROPBEAR_SVR_AGENTFWD) || (DROPBEAR_X11FWD)) #define DROPBEAR_CLI_MULTIHOP ((DROPBEAR_CLI_NETCAT) && (DROPBEAR_CLI_PROXYCMD)) #define ENABLE_CONNECT_UNIX ((DROPBEAR_CLI_AGENTFWD) || (DROPBEAR_USE_PRNGD)) /* if we're using authorized_keys or known_hosts */ #define DROPBEAR_KEY_LINES ((DROPBEAR_CLIENT) || (DROPBEAR_SVR_PUBKEY_AUTH)) /* Changing this is inadvisable, it appears to have problems * with flushing compressed data */ #define DROPBEAR_ZLIB_MEM_LEVEL 8 #if (DROPBEAR_SVR_PASSWORD_AUTH) && (DROPBEAR_SVR_PAM_AUTH) #error "You can't turn on PASSWORD and PAM auth both at once. Fix it in localoptions.h" #endif /* PAM requires ./configure --enable-pam */ #if !defined(HAVE_LIBPAM) && DROPBEAR_SVR_PAM_AUTH #error "DROPBEAR_SVR_PATM_AUTH requires PAM headers. Perhaps ./configure --enable-pam ?" #endif #if DROPBEAR_SVR_PASSWORD_AUTH && !HAVE_CRYPT #error "DROPBEAR_SVR_PASSWORD_AUTH requires `crypt()'." #endif #if !(DROPBEAR_SVR_PASSWORD_AUTH || DROPBEAR_SVR_PAM_AUTH || DROPBEAR_SVR_PUBKEY_AUTH) #error "At least one server authentication type must be enabled. DROPBEAR_SVR_PUBKEY_AUTH and DROPBEAR_SVR_PASSWORD_AUTH are recommended." #endif #if (DROPBEAR_PLUGIN && !DROPBEAR_SVR_PUBKEY_AUTH) #error "You must define DROPBEAR_SVR_PUBKEY_AUTH in order to use plugins" #endif #if !(DROPBEAR_AES128 || DROPBEAR_3DES || DROPBEAR_AES256 || DROPBEAR_CHACHA20POLY1305) #error "At least one encryption algorithm must be enabled. AES128 is recommended." #endif #if !(DROPBEAR_RSA || DROPBEAR_DSS || DROPBEAR_ECDSA || DROPBEAR_ED25519) #error "At least one hostkey or public-key algorithm must be enabled; RSA is recommended." #endif /* Source for randomness. This must be able to provide hundreds of bytes per SSH * connection without blocking. */ #ifndef DROPBEAR_URANDOM_DEV #define DROPBEAR_URANDOM_DEV "/dev/urandom" #endif /* client keyboard interactive authentication is often used for password auth. rfc4256 */ #define DROPBEAR_CLI_INTERACT_AUTH (DROPBEAR_CLI_PASSWORD_AUTH) /* We use dropbear_client and dropbear_server as shortcuts to avoid redundant * code, if we're just compiling as client or server */ #if (DROPBEAR_SERVER) && (DROPBEAR_CLIENT) #define IS_DROPBEAR_SERVER (ses.isserver == 1) #define IS_DROPBEAR_CLIENT (ses.isserver == 0) #elif DROPBEAR_SERVER #define IS_DROPBEAR_SERVER 1 #define IS_DROPBEAR_CLIENT 0 #elif DROPBEAR_CLIENT #define IS_DROPBEAR_SERVER 0 #define IS_DROPBEAR_CLIENT 1 #else /* Just building key utils? */ #define IS_DROPBEAR_SERVER 0 #define IS_DROPBEAR_CLIENT 0 #endif /* neither DROPBEAR_SERVER nor DROPBEAR_CLIENT */ #ifdef HAVE_FORK #define DROPBEAR_VFORK 0 #else #define DROPBEAR_VFORK 1 #endif #ifndef DROPBEAR_LISTEN_BACKLOG #if MAX_UNAUTH_CLIENTS > MAX_CHANNELS #define DROPBEAR_LISTEN_BACKLOG MAX_UNAUTH_CLIENTS #else #define DROPBEAR_LISTEN_BACKLOG MAX_CHANNELS #endif #endif /* free memory before exiting */ #define DROPBEAR_CLEANUP 1 /* Use this string since some implementations might special-case it */ #define DROPBEAR_KEEPALIVE_STRING "[email protected]" /* Linux will attempt TCP fast open, falling back if not supported by the kernel. * Currently server is enabled but client is disabled by default until there * is further compatibility testing */ #ifdef __linux__ #define DROPBEAR_SERVER_TCP_FAST_OPEN 1 #define DROPBEAR_CLIENT_TCP_FAST_OPEN 0 #else #define DROPBEAR_SERVER_TCP_FAST_OPEN 0 #define DROPBEAR_CLIENT_TCP_FAST_OPEN 0 #endif #define DROPBEAR_TRACKING_MALLOC (DROPBEAR_FUZZ) /* Used to work around Memory Sanitizer false positives */ #if defined(__has_feature) # if __has_feature(memory_sanitizer) # define DROPBEAR_MSAN 1 # endif #endif #ifndef DROPBEAR_MSAN #define DROPBEAR_MSAN 0 #endif /* no include guard for this file */