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Diffstat (limited to 'src/sysoptions.h')
| -rw-r--r-- | src/sysoptions.h | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/src/sysoptions.h b/src/sysoptions.h new file mode 100644 index 0000000..82249f5 --- /dev/null +++ b/src/sysoptions.h @@ -0,0 +1,398 @@ +/******************************************************************* + * 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 "2022.83" +#endif + +#define LOCAL_IDENT "SSH-2.0-dropbear_" DROPBEAR_VERSION +#define PROGNAME "dropbear" + +#ifndef DROPBEAR_CLIENT +#define DROPBEAR_CLIENT 0 +#endif + +#ifndef DROPBEAR_SERVER +#define DROPBEAR_SERVER 0 +#endif + +/* 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 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" + +/* Default contents of /etc/shells if system getusershell() doesn't exist. + * Paths taken from getusershell(3) manpage. These can be customised + * on other platforms. One the commandline for CFLAGS it would look like eg + -DCOMPAT_USER_SHELLS='"/bin/sh","/apps/bin/sh","/data/bin/zsh"' + */ +#ifndef COMPAT_USER_SHELLS +#define COMPAT_USER_SHELLS "/bin/sh","/bin/csh" +#endif + +#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 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 + +#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_SHA256 +#define DROPBEAR_RSA_SHA256 DROPBEAR_RSA +#endif + +/* Miller-Rabin primality testing is sufficient for RSA but not DSS. + * It's a compile-time setting for libtommath, we can get a speedup + * for key generation if DSS is disabled. + * https://github.com/mkj/dropbear/issues/174#issuecomment-1267374858 + */ +#if !DROPBEAR_DSS +#define LTM_USE_ONLY_MR 1 +#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_DH_GROUP14 ((DROPBEAR_DH_GROUP14_SHA256) || (DROPBEAR_DH_GROUP14_SHA1)) + +#define DROPBEAR_NORMAL_DH ((DROPBEAR_DH_GROUP1) || (DROPBEAR_DH_GROUP14) || (DROPBEAR_DH_GROUP16)) + +#ifndef DROPBEAR_SK_ECDSA +#define DROPBEAR_SK_ECDSA DROPBEAR_SK_KEYS +#endif +#ifndef DROPBEAR_SK_ED25519 +#define DROPBEAR_SK_ED25519 DROPBEAR_SK_KEYS +#endif + +/* 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 "keepalive@openssh.com" + +/* 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 + +#ifndef DEBUG_DSS_VERIFY +#define DEBUG_DSS_VERIFY 0 +#endif + +#ifndef DROPBEAR_MULTI +#define DROPBEAR_MULTI 0 +#endif + +/* Fuzzing expects all key types to be enabled */ +#if DROPBEAR_FUZZ +#if defined(DROPBEAR_DSS) +#undef DROPBEAR_DSS +#endif +#define DROPBEAR_DSS 1 +#endif + +/* no include guard for this file */ |