sysoptions.h - third_party/dropbear - Git at Google

 /*******************************************************************
  * 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 "2016.74"
 #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))

 /* 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 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 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"

 /* Required for pubkey auth */
 #define DROPBEAR_SIGNKEY_VERIFY ((DROPBEAR_SVR_PUBKEY_AUTH) || (DROPBEAR_CLIENT))

 #define SHA1_HASH_SIZE 20
 #define MD5_HASH_SIZE 16
 #define MAX_HASH_SIZE 64 /* sha512 */

 #define MAX_KEY_LEN 32 /* 256 bits for aes256 etc */
 #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


 #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

 /* hashes which will be linked and registered */
 #define DROPBEAR_SHA256 ((DROPBEAR_SHA2_256_HMAC) || (DROPBEAR_ECC_256)  \
  			|| (DROPBEAR_CURVE25519) || (DROPBEAR_DH_GROUP14_SHA256))
 #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))
 #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))

 /* 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 20

 /* 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 (1024*1024) /* 1 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 3

 /* 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_TWOFISH ((DROPBEAR_TWOFISH256) || (DROPBEAR_TWOFISH128))

 #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_PRNGD_SOCKET))

 /* 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 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 (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

 #if MAX_UNAUTH_CLIENTS > MAX_CHANNELS
 #define DROPBEAR_LISTEN_BACKLOG MAX_UNAUTH_CLIENTS
 #else
 #define DROPBEAR_LISTEN_BACKLOG MAX_CHANNELS
 #endif

 #ifndef DROPBEAR_NONE_CIPHER
 #define DROPBEAR_NONE_CIPHER 0
 #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

 /* no include guard for this file */
	/*******************************************************************
	* 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 "2016.74"
	#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))

	/* 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 512
	#endif
	#ifndef MIN_RSA_KEYLEN
	#define MIN_RSA_KEYLEN 512
	#endif

	#define MAX_BANNER_SIZE 2000 /* this is 2580 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"

	/* Required for pubkey auth */
	#define DROPBEAR_SIGNKEY_VERIFY ((DROPBEAR_SVR_PUBKEY_AUTH) \|\| (DROPBEAR_CLIENT))

	#define SHA1_HASH_SIZE 20
	#define MD5_HASH_SIZE 16
	#define MAX_HASH_SIZE 64 /* sha512 */

	#define MAX_KEY_LEN 32 /* 256 bits for aes256 etc */
	#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


	#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

	/* hashes which will be linked and registered */
	#define DROPBEAR_SHA256 ((DROPBEAR_SHA2_256_HMAC) \|\| (DROPBEAR_ECC_256) \
	\|\| (DROPBEAR_CURVE25519) \|\| (DROPBEAR_DH_GROUP14_SHA256))
	#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))
	#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))

	/* 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 20

	/* 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 (10241024) / 1 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 3

	/* 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_TWOFISH ((DROPBEAR_TWOFISH256) \|\| (DROPBEAR_TWOFISH128))

	#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_PRNGD_SOCKET))

	/* 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 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 (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

	#if MAX_UNAUTH_CLIENTS > MAX_CHANNELS
	#define DROPBEAR_LISTEN_BACKLOG MAX_UNAUTH_CLIENTS
	#else
	#define DROPBEAR_LISTEN_BACKLOG MAX_CHANNELS
	#endif

	#ifndef DROPBEAR_NONE_CIPHER
	#define DROPBEAR_NONE_CIPHER 0
	#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

	/* no include guard for this file */