xref: /openssh-portable/servconf.h (revision 793b583d)
1 /* $OpenBSD: servconf.h,v 1.147 2020/10/16 13:26:13 djm Exp $ */
2 
3 /*
4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6  *                    All rights reserved
7  * Definitions for server configuration data and for the functions reading it.
8  *
9  * As far as I am concerned, the code I have written for this software
10  * can be used freely for any purpose.  Any derived versions of this
11  * software must be clearly marked as such, and if the derived work is
12  * incompatible with the protocol description in the RFC file, it must be
13  * called by a name other than "ssh" or "Secure Shell".
14  */
15 
16 #ifndef SERVCONF_H
17 #define SERVCONF_H
18 
19 #include <openbsd-compat/sys-queue.h>
20 
21 #define MAX_PORTS		256	/* Max # ports. */
22 
23 #define MAX_SUBSYSTEMS		256	/* Max # subsystems. */
24 
25 /* permit_root_login */
26 #define	PERMIT_NOT_SET		-1
27 #define	PERMIT_NO		0
28 #define	PERMIT_FORCED_ONLY	1
29 #define	PERMIT_NO_PASSWD	2
30 #define	PERMIT_YES		3
31 
32 /* use_privsep */
33 #define PRIVSEP_OFF		0
34 #define PRIVSEP_ON		1
35 #define PRIVSEP_NOSANDBOX	2
36 
37 /* PermitOpen */
38 #define PERMITOPEN_ANY		0
39 #define PERMITOPEN_NONE		-2
40 
41 /* IgnoreRhosts */
42 #define IGNORE_RHOSTS_NO	0
43 #define IGNORE_RHOSTS_YES	1
44 #define IGNORE_RHOSTS_SHOSTS	2
45 
46 #define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */
47 #define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */
48 
49 /* Magic name for internal sftp-server */
50 #define INTERNAL_SFTP_NAME	"internal-sftp"
51 
52 /* PubkeyAuthOptions flags */
53 #define PUBKEYAUTH_TOUCH_REQUIRED	(1)
54 #define PUBKEYAUTH_VERIFY_REQUIRED	(1<<1)
55 
56 struct ssh;
57 struct fwd_perm_list;
58 
59 /*
60  * Used to store addresses from ListenAddr directives. These may be
61  * incomplete, as they may specify addresses that need to be merged
62  * with any ports requested by ListenPort.
63  */
64 struct queued_listenaddr {
65 	char *addr;
66 	int port; /* <=0 if unspecified */
67 	char *rdomain;
68 };
69 
70 /* Resolved listen addresses, grouped by optional routing domain */
71 struct listenaddr {
72 	char *rdomain;
73 	struct addrinfo *addrs;
74 };
75 
76 typedef struct {
77 	u_int	num_ports;
78 	u_int	ports_from_cmdline;
79 	int	ports[MAX_PORTS];	/* Port number to listen on. */
80 	struct queued_listenaddr *queued_listen_addrs;
81 	u_int	num_queued_listens;
82 	struct listenaddr *listen_addrs;
83 	u_int	num_listen_addrs;
84 	int	address_family;		/* Address family used by the server. */
85 
86 	char	*routing_domain;	/* Bind session to routing domain */
87 
88 	char   **host_key_files;	/* Files containing host keys. */
89 	int	*host_key_file_userprovided; /* Key was specified by user. */
90 	u_int	num_host_key_files;     /* Number of files for host keys. */
91 	char   **host_cert_files;	/* Files containing host certs. */
92 	u_int	num_host_cert_files;	/* Number of files for host certs. */
93 
94 	char   *host_key_agent;		/* ssh-agent socket for host keys. */
95 	char   *pid_file;		/* Where to put our pid */
96 	int     login_grace_time;	/* Disconnect if no auth in this time
97 					 * (sec). */
98 	int     permit_root_login;	/* PERMIT_*, see above */
99 	int     ignore_rhosts;	/* Ignore .rhosts and .shosts. */
100 	int     ignore_user_known_hosts;	/* Ignore ~/.ssh/known_hosts
101 						 * for RhostsRsaAuth */
102 	int     print_motd;	/* If true, print /etc/motd. */
103 	int	print_lastlog;	/* If true, print lastlog */
104 	int     x11_forwarding;	/* If true, permit inet (spoofing) X11 fwd. */
105 	int     x11_display_offset;	/* What DISPLAY number to start
106 					 * searching at */
107 	int     x11_use_localhost;	/* If true, use localhost for fake X11 server. */
108 	char   *xauth_location;	/* Location of xauth program */
109 	int	permit_tty;	/* If false, deny pty allocation */
110 	int	permit_user_rc;	/* If false, deny ~/.ssh/rc execution */
111 	int     strict_modes;	/* If true, require string home dir modes. */
112 	int     tcp_keep_alive;	/* If true, set SO_KEEPALIVE. */
113 	int	ip_qos_interactive;	/* IP ToS/DSCP/class for interactive */
114 	int	ip_qos_bulk;		/* IP ToS/DSCP/class for bulk traffic */
115 	char   *ciphers;	/* Supported SSH2 ciphers. */
116 	char   *macs;		/* Supported SSH2 macs. */
117 	char   *kex_algorithms;	/* SSH2 kex methods in order of preference. */
118 	struct ForwardOptions fwd_opts;	/* forwarding options */
119 	SyslogFacility log_facility;	/* Facility for system logging. */
120 	LogLevel log_level;	/* Level for system logging. */
121 	u_int	num_log_verbose;	/* Verbose log overrides */
122 	char	**log_verbose;
123 	int     hostbased_authentication;	/* If true, permit ssh2 hostbased auth */
124 	int     hostbased_uses_name_from_packet_only; /* experimental */
125 	char   *hostbased_key_types;	/* Key types allowed for hostbased */
126 	char   *hostkeyalgorithms;	/* SSH2 server key types */
127 	char   *ca_sign_algorithms;	/* Allowed CA signature algorithms */
128 	int     pubkey_authentication;	/* If true, permit ssh2 pubkey authentication. */
129 	char   *pubkey_key_types;	/* Key types allowed for public key */
130 	int	pubkey_auth_options;	/* -1 or mask of PUBKEYAUTH_* flags */
131 	int     kerberos_authentication;	/* If true, permit Kerberos
132 						 * authentication. */
133 	int     kerberos_or_local_passwd;	/* If true, permit kerberos
134 						 * and any other password
135 						 * authentication mechanism,
136 						 * such as SecurID or
137 						 * /etc/passwd */
138 	int     kerberos_ticket_cleanup;	/* If true, destroy ticket
139 						 * file on logout. */
140 	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
141 						 * authenticated with Kerberos. */
142 	int     gss_authentication;	/* If true, permit GSSAPI authentication */
143 	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
144 	int     gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
145 	int     password_authentication;	/* If true, permit password
146 						 * authentication. */
147 	int     kbd_interactive_authentication;	/* If true, permit */
148 	int     challenge_response_authentication;
149 	int     permit_empty_passwd;	/* If false, do not permit empty
150 					 * passwords. */
151 	int     permit_user_env;	/* If true, read ~/.ssh/environment */
152 	char   *permit_user_env_allowlist; /* pattern-list of allowed env names */
153 	int     compression;	/* If true, compression is allowed */
154 	int	allow_tcp_forwarding; /* One of FORWARD_* */
155 	int	allow_streamlocal_forwarding; /* One of FORWARD_* */
156 	int	allow_agent_forwarding;
157 	int	disable_forwarding;
158 	u_int num_allow_users;
159 	char   **allow_users;
160 	u_int num_deny_users;
161 	char   **deny_users;
162 	u_int num_allow_groups;
163 	char   **allow_groups;
164 	u_int num_deny_groups;
165 	char   **deny_groups;
166 
167 	u_int num_subsystems;
168 	char   *subsystem_name[MAX_SUBSYSTEMS];
169 	char   *subsystem_command[MAX_SUBSYSTEMS];
170 	char   *subsystem_args[MAX_SUBSYSTEMS];
171 
172 	u_int num_accept_env;
173 	char   **accept_env;
174 	u_int num_setenv;
175 	char   **setenv;
176 
177 	int	max_startups_begin;
178 	int	max_startups_rate;
179 	int	max_startups;
180 	int	max_authtries;
181 	int	max_sessions;
182 	char   *banner;			/* SSH-2 banner message */
183 	int	use_dns;
184 	int	client_alive_interval;	/*
185 					 * poke the client this often to
186 					 * see if it's still there
187 					 */
188 	int	client_alive_count_max;	/*
189 					 * If the client is unresponsive
190 					 * for this many intervals above,
191 					 * disconnect the session
192 					 */
193 
194 	u_int	num_authkeys_files;	/* Files containing public keys */
195 	char   **authorized_keys_files;
196 
197 	char   *adm_forced_command;
198 
199 	int	use_pam;		/* Enable auth via PAM */
200 
201 	int	permit_tun;
202 
203 	char   **permitted_opens;	/* May also be one of PERMITOPEN_* */
204 	u_int   num_permitted_opens;
205 	char   **permitted_listens; /* May also be one of PERMITOPEN_* */
206 	u_int   num_permitted_listens;
207 
208 	char   *chroot_directory;
209 	char   *revoked_keys_file;
210 	char   *trusted_user_ca_keys;
211 	char   *authorized_keys_command;
212 	char   *authorized_keys_command_user;
213 	char   *authorized_principals_file;
214 	char   *authorized_principals_command;
215 	char   *authorized_principals_command_user;
216 
217 	int64_t rekey_limit;
218 	int	rekey_interval;
219 
220 	char   *version_addendum;	/* Appended to SSH banner */
221 
222 	u_int	num_auth_methods;
223 	char   **auth_methods;
224 
225 	int	fingerprint_hash;
226 	int	expose_userauth_info;
227 	u_int64_t timing_secret;
228 	char   *sk_provider;
229 }       ServerOptions;
230 
231 /* Information about the incoming connection as used by Match */
232 struct connection_info {
233 	const char *user;
234 	const char *host;	/* possibly resolved hostname */
235 	const char *address; 	/* remote address */
236 	const char *laddress;	/* local address */
237 	int lport;		/* local port */
238 	const char *rdomain;	/* routing domain if available */
239 	int test;		/* test mode, allow some attributes to be
240 				 * unspecified */
241 };
242 
243 /* List of included files for re-exec from the parsed configuration */
244 struct include_item {
245 	char *selector;
246 	char *filename;
247 	struct sshbuf *contents;
248 	TAILQ_ENTRY(include_item) entry;
249 };
250 TAILQ_HEAD(include_list, include_item);
251 
252 
253 /*
254  * These are string config options that must be copied between the
255  * Match sub-config and the main config, and must be sent from the
256  * privsep child to the privsep master. We use a macro to ensure all
257  * the options are copied and the copies are done in the correct order.
258  *
259  * NB. an option must appear in servconf.c:copy_set_server_options() or
260  * COPY_MATCH_STRING_OPTS here but never both.
261  */
262 #define COPY_MATCH_STRING_OPTS() do { \
263 		M_CP_STROPT(banner); \
264 		M_CP_STROPT(trusted_user_ca_keys); \
265 		M_CP_STROPT(revoked_keys_file); \
266 		M_CP_STROPT(authorized_keys_command); \
267 		M_CP_STROPT(authorized_keys_command_user); \
268 		M_CP_STROPT(authorized_principals_file); \
269 		M_CP_STROPT(authorized_principals_command); \
270 		M_CP_STROPT(authorized_principals_command_user); \
271 		M_CP_STROPT(hostbased_key_types); \
272 		M_CP_STROPT(pubkey_key_types); \
273 		M_CP_STROPT(ca_sign_algorithms); \
274 		M_CP_STROPT(routing_domain); \
275 		M_CP_STROPT(permit_user_env_allowlist); \
276 		M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
277 		M_CP_STRARRAYOPT(allow_users, num_allow_users); \
278 		M_CP_STRARRAYOPT(deny_users, num_deny_users); \
279 		M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
280 		M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
281 		M_CP_STRARRAYOPT(accept_env, num_accept_env); \
282 		M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
283 		M_CP_STRARRAYOPT(permitted_opens, num_permitted_opens); \
284 		M_CP_STRARRAYOPT(permitted_listens, num_permitted_listens); \
285 		M_CP_STRARRAYOPT(log_verbose, num_log_verbose); \
286 	} while (0)
287 
288 struct connection_info *get_connection_info(struct ssh *, int, int);
289 void	 initialize_server_options(ServerOptions *);
290 void	 fill_default_server_options(ServerOptions *);
291 int	 process_server_config_line(ServerOptions *, char *, const char *, int,
292 	     int *, struct connection_info *, struct include_list *includes);
293 void	 process_permitopen(struct ssh *ssh, ServerOptions *options);
294 void	 load_server_config(const char *, struct sshbuf *);
295 void	 parse_server_config(ServerOptions *, const char *, struct sshbuf *,
296 	     struct include_list *includes, struct connection_info *);
297 void	 parse_server_match_config(ServerOptions *,
298 	     struct include_list *includes, struct connection_info *);
299 int	 parse_server_match_testspec(struct connection_info *, char *);
300 int	 server_match_spec_complete(struct connection_info *);
301 void	 copy_set_server_options(ServerOptions *, ServerOptions *, int);
302 void	 dump_config(ServerOptions *);
303 char	*derelativise_path(const char *);
304 void	 servconf_add_hostkey(const char *, const int,
305 	    ServerOptions *, const char *path, int);
306 void	 servconf_add_hostcert(const char *, const int,
307 	    ServerOptions *, const char *path);
308 
309 #endif				/* SERVCONF_H */
310