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      1 /*	$NetBSD: readconf.h,v 1.38 2026/04/08 18:58:41 christos Exp $	*/
      2 /* $OpenBSD: readconf.h,v 1.163 2026/03/30 07:18:24 djm Exp $ */
      3 
      4 /*
      5  * Author: Tatu Ylonen <ylo (at) cs.hut.fi>
      6  * Copyright (c) 1995 Tatu Ylonen <ylo (at) cs.hut.fi>, Espoo, Finland
      7  *                    All rights reserved
      8  * Functions for reading the configuration file.
      9  *
     10  * As far as I am concerned, the code I have written for this software
     11  * can be used freely for any purpose.  Any derived versions of this
     12  * software must be clearly marked as such, and if the derived work is
     13  * incompatible with the protocol description in the RFC file, it must be
     14  * called by a name other than "ssh" or "Secure Shell".
     15  */
     16 
     17 #ifndef READCONF_H
     18 #define READCONF_H
     19 
     20 /* Data structure for representing option data. */
     21 
     22 #define SSH_MAX_HOSTS_FILES	32
     23 #define PATH_MAX_SUN		(sizeof((struct sockaddr_un *)0)->sun_path)
     24 
     25 struct allowed_cname {
     26 	char *source_list;
     27 	char *target_list;
     28 };
     29 
     30 typedef struct {
     31 	char   *host_arg;	/* Host arg as specified on command line. */
     32 	int     forward_agent;	/* Forward authentication agent. */
     33 	char   *forward_agent_sock_path; /* Optional path of the agent. */
     34 	int     forward_x11;	/* Forward X11 display. */
     35 	int     forward_x11_timeout;	/* Expiration for Cookies */
     36 	int     forward_x11_trusted;	/* Trust Forward X11 display. */
     37 	int     exit_on_forward_failure;	/* Exit if bind(2) fails for -L/-R */
     38 	char   *xauth_location;	/* Location for xauth program */
     39 	struct ForwardOptions fwd_opts;	/* forwarding options */
     40 	int     pubkey_authentication;	/* Try ssh2 pubkey authentication. */
     41 	int     hostbased_authentication;	/* ssh2's rhosts_rsa */
     42 #if defined(KRB4) || defined(KRB5)
     43 	int     kerberos_authentication;	/* Try Kerberos authentication. */
     44 #endif
     45 #if defined(AFS) || defined(KRB5)
     46 	int     kerberos_tgt_passing;	/* Try Kerberos TGT passing. */
     47 #endif
     48 #ifdef AFS
     49 	int     afs_token_passing;	/* Try AFS token passing. */
     50 #endif
     51 					/* Try S/Key or TIS, authentication. */
     52 	int     gss_authentication;	/* Try GSS authentication */
     53 	int     gss_deleg_creds;	/* Delegate GSS credentials */
     54 	int     password_authentication;	/* Try password
     55 						 * authentication. */
     56 	int     kbd_interactive_authentication; /* Try keyboard-interactive auth. */
     57 	char	*kbd_interactive_devices; /* Keyboard-interactive auth devices. */
     58 	int     batch_mode;	/* Batch mode: do not ask for passwords. */
     59 	int     check_host_ip;	/* Also keep track of keys for IP address */
     60 	int     strict_host_key_checking;	/* Strict host key checking. */
     61 	int     compression;	/* Compress packets in both directions. */
     62 	int     tcp_keep_alive;	/* Set SO_KEEPALIVE. */
     63 	int     tcp_rcv_buf; /* user switch to set tcp recv buffer */
     64 	int	tcp_rcv_buf_poll; /* Option to poll recv buf every window transfer */
     65 	int 	hpn_disabled; 	 /* Switch to disable HPN buffer management */
     66 	int	hpn_buffer_size; /* User definable size for HPN buffer window */
     67 
     68 	int	ip_qos_interactive;	/* DSCP value for interactive */
     69 	int	ip_qos_bulk;		/* DSCP value for bulk traffic */
     70 	SyslogFacility log_facility;	/* Facility for system logging. */
     71 	LogLevel log_level;	/* Level for logging. */
     72 	u_int	num_log_verbose;	/* Verbose log overrides */
     73 	char   **log_verbose;
     74 	int     port;		/* Port to connect. */
     75 	int     address_family;
     76 	int     connection_attempts;	/* Max attempts (seconds) before
     77 					 * giving up */
     78 	int     connection_timeout;	/* Max time (seconds) before
     79 					 * aborting connection attempt */
     80 	int     number_of_password_prompts;	/* Max number of password
     81 						 * prompts. */
     82 	char   *ciphers;	/* SSH2 ciphers in order of preference. */
     83 	char   *macs;		/* SSH2 macs in order of preference. */
     84 	char   *hostkeyalgorithms;	/* SSH2 server key types in order of preference. */
     85 	char   *kex_algorithms;	/* SSH2 kex methods in order of preference. */
     86 	int	kex_algorithms_set; /* KexAlgorithms was set by the user */
     87 	char   *ca_sign_algorithms;	/* Allowed CA signature algorithms */
     88 	char   *hostname;	/* Real host to connect. */
     89 	char   *tag;		/* Configuration tag name. */
     90 	char   *host_key_alias;	/* hostname alias for .ssh/known_hosts */
     91 	char   *proxy_command;	/* Proxy command for connecting the host. */
     92 	char   *user;		/* User to log in as. */
     93 	int     escape_char;	/* Escape character; -2 = none */
     94 
     95 	u_int	num_system_hostfiles;	/* Paths for /etc/ssh/ssh_known_hosts */
     96 	char   *system_hostfiles[SSH_MAX_HOSTS_FILES];
     97 	u_int	num_user_hostfiles;	/* Path for $HOME/.ssh/known_hosts */
     98 	char   *user_hostfiles[SSH_MAX_HOSTS_FILES];
     99 	char   *preferred_authentications;
    100 	char   *bind_address;	/* local socket address for connection to sshd */
    101 	char   *bind_interface;	/* local interface for bind address */
    102 	int	ipv6_prefer_temporary; /* Prefer temporary IPv6 address */
    103 	char   *pkcs11_provider; /* PKCS#11 provider */
    104 	char   *sk_provider; /* Security key provider */
    105 	int	verify_host_key_dns;	/* Verify host key using DNS */
    106 
    107 	int     num_identity_files;	/* Number of files for identities. */
    108 	char   *identity_files[SSH_MAX_IDENTITY_FILES];
    109 	int    identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
    110 	struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
    111 
    112 	int	num_certificate_files; /* Number of extra certificates for ssh. */
    113 	char	*certificate_files[SSH_MAX_CERTIFICATE_FILES];
    114 	int	certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
    115 	struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
    116 
    117 	int	add_keys_to_agent;
    118 	int	add_keys_to_agent_lifespan;
    119 	char   *identity_agent;		/* Optional path to ssh-agent socket */
    120 
    121 	/* Local TCP/IP forward requests. */
    122 	int     num_local_forwards;
    123 	struct Forward *local_forwards;
    124 
    125 	/* Remote TCP/IP forward requests. */
    126 	int     num_remote_forwards;
    127 	struct Forward *remote_forwards;
    128 	int	clear_forwardings;
    129 
    130 	/* Restrict remote dynamic forwarding */
    131 	char  **permitted_remote_opens;
    132 	u_int	num_permitted_remote_opens;
    133 
    134 	/* stdio forwarding (-W) host and port */
    135 	char   *stdio_forward_host;
    136 	int	stdio_forward_port;
    137 
    138 	int	enable_ssh_keysign;
    139 	int64_t rekey_limit;
    140 	int	rekey_interval;
    141 	int     none_switch;    /* Use none cipher */
    142 	int     none_enabled;   /* Allow none to be used */
    143 	int	no_host_authentication_for_localhost;
    144 	int	identities_only;
    145 	int	server_alive_interval;
    146 	int	server_alive_count_max;
    147 
    148 	u_int	num_send_env;
    149 	char	**send_env;
    150 	u_int	num_setenv;
    151 	char	**setenv;
    152 
    153 	char	*control_path;
    154 	int	control_master;
    155 	int     control_persist; /* ControlPersist flag */
    156 	int     control_persist_timeout; /* ControlPersist timeout (seconds) */
    157 
    158 	int	hash_known_hosts;
    159 
    160 	int	tun_open;	/* tun(4) */
    161 	int     tun_local;	/* force tun device (optional) */
    162 	int     tun_remote;	/* force tun device (optional) */
    163 
    164 	char	*local_command;
    165 	int	permit_local_command;
    166 	char	*remote_command;
    167 	int	visual_host_key;
    168 
    169 	int	request_tty;
    170 	int	send_version_first;
    171 	int	session_type;
    172 	int	stdin_null;
    173 	int	fork_after_authentication;
    174 
    175 	int	proxy_use_fdpass;
    176 
    177 	int	num_canonical_domains;
    178 	char	**canonical_domains;
    179 	int	canonicalize_hostname;
    180 	int	canonicalize_max_dots;
    181 	int	canonicalize_fallback_local;
    182 	int	num_permitted_cnames;
    183 	struct allowed_cname *permitted_cnames;
    184 
    185 	u_int	num_revoked_host_keys;
    186 	char	**revoked_host_keys;
    187 
    188 	int	 fingerprint_hash;
    189 
    190 	int	 update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */
    191 
    192 	char   *hostbased_accepted_algos;
    193 	char   *pubkey_accepted_algos;
    194 
    195 	char   *jump_user;
    196 	char   *jump_host;
    197 	int	jump_port;
    198 	char   *jump_extra;
    199 
    200 	char   *known_hosts_command;
    201 
    202 	int	required_rsa_size;	/* minimum size of RSA keys */
    203 	int	enable_escape_commandline;	/* ~C commandline */
    204 	int	obscure_keystroke_timing_interval;
    205 	int	warn_weak_crypto;
    206 
    207 	char	**channel_timeouts;	/* inactivity timeout by channel type */
    208 	u_int	num_channel_timeouts;
    209 
    210 	char	*version_addendum;
    211 
    212 	char	*ignored_unknown; /* Pattern list of unknown tokens to ignore */
    213 }       Options;
    214 
    215 #define SSH_PUBKEY_AUTH_NO	0x00
    216 #define SSH_PUBKEY_AUTH_UNBOUND	0x01
    217 #define SSH_PUBKEY_AUTH_HBOUND	0x02
    218 #define SSH_PUBKEY_AUTH_ALL	0x03
    219 
    220 #define SSH_CANONICALISE_NO	0
    221 #define SSH_CANONICALISE_YES	1
    222 #define SSH_CANONICALISE_ALWAYS	2
    223 
    224 #define SSHCTL_MASTER_NO	0
    225 #define SSHCTL_MASTER_YES	1
    226 #define SSHCTL_MASTER_AUTO	2
    227 #define SSHCTL_MASTER_ASK	3
    228 #define SSHCTL_MASTER_AUTO_ASK	4
    229 
    230 #define REQUEST_TTY_AUTO	0
    231 #define REQUEST_TTY_NO		1
    232 #define REQUEST_TTY_YES		2
    233 #define REQUEST_TTY_FORCE	3
    234 
    235 #define SESSION_TYPE_NONE	0
    236 #define SESSION_TYPE_SUBSYSTEM	1
    237 #define SESSION_TYPE_DEFAULT	2
    238 
    239 #define SSHCONF_CHECKPERM	1  /* check permissions on config file */
    240 #define SSHCONF_USERCONF	2  /* user provided config file not system */
    241 #define SSHCONF_FINAL		4  /* Final pass over config, after canon. */
    242 #define SSHCONF_NEVERMATCH	8  /* Match/Host never matches; internal only */
    243 
    244 #define SSH_UPDATE_HOSTKEYS_NO	0
    245 #define SSH_UPDATE_HOSTKEYS_YES	1
    246 #define SSH_UPDATE_HOSTKEYS_ASK	2
    247 
    248 #define SSH_STRICT_HOSTKEY_OFF	0
    249 #define SSH_STRICT_HOSTKEY_NEW	1
    250 #define SSH_STRICT_HOSTKEY_YES	2
    251 #define SSH_STRICT_HOSTKEY_ASK	3
    252 
    253 /* ObscureKeystrokes parameters */
    254 #define SSH_KEYSTROKE_DEFAULT_INTERVAL_MS	20
    255 #define SSH_KEYSTROKE_CHAFF_MIN_MS		1024
    256 #define SSH_KEYSTROKE_CHAFF_RNG_MS		2048
    257 
    258 const char *kex_default_pk_alg(void);
    259 char	*ssh_connection_hash(const char *thishost, const char *host,
    260     const char *portstr, const char *user, const char *jump_host);
    261 void     initialize_options(Options *);
    262 int      fill_default_options(Options *);
    263 void	 fill_default_options_for_canonicalization(Options *);
    264 void	 free_options(Options *o);
    265 int	 process_config_line(Options *, struct passwd *, const char *,
    266     const char *, const char *, char *, const char *, int, int *, int);
    267 int	 read_config_file(const char *, struct passwd *, const char *,
    268     const char *, const char *, Options *, int, int *);
    269 int	 parse_forward(struct Forward *, const char *, int, int);
    270 int	 ssh_valid_hostname(const char *);
    271 int	 ssh_valid_ruser(const char *);
    272 int	 parse_jump(const char *, Options *, int, int);
    273 int	 parse_ssh_uri(const char *, char **, char **, int *);
    274 int	 default_ssh_port(void);
    275 int	 option_clear_or_none(const char *);
    276 int	 config_has_permitted_cnames(Options *);
    277 void	 dump_client_config(Options *o, const char *host);
    278 
    279 void	 add_local_forward(Options *, const struct Forward *);
    280 void	 add_remote_forward(Options *, const struct Forward *);
    281 void	 add_identity_file(Options *, const char *, const char *, int);
    282 void	 add_certificate_file(Options *, const char *, int);
    283 
    284 #endif				/* READCONF_H */
    285