1/* $OpenBSD: servconf.h,v 1.160 2023/09/06 23:35:35 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/* permit_root_login */
24#define	PERMIT_NOT_SET		-1
25#define	PERMIT_NO		0
26#define	PERMIT_FORCED_ONLY	1
27#define	PERMIT_NO_PASSWD	2
28#define	PERMIT_YES		3
29
30/* use_privsep */
31#define PRIVSEP_OFF		0
32#define PRIVSEP_ON		1
33#define PRIVSEP_NOSANDBOX	2
34
35/* PermitOpen */
36#define PERMITOPEN_ANY		0
37#define PERMITOPEN_NONE		-2
38
39/* IgnoreRhosts */
40#define IGNORE_RHOSTS_NO	0
41#define IGNORE_RHOSTS_YES	1
42#define IGNORE_RHOSTS_SHOSTS	2
43
44#define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */
45#define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */
46
47/* Magic name for internal sftp-server */
48#define INTERNAL_SFTP_NAME	"internal-sftp"
49
50/* PubkeyAuthOptions flags */
51#define PUBKEYAUTH_TOUCH_REQUIRED	(1)
52#define PUBKEYAUTH_VERIFY_REQUIRED	(1<<1)
53
54struct ssh;
55struct fwd_perm_list;
56
57/*
58 * Used to store addresses from ListenAddr directives. These may be
59 * incomplete, as they may specify addresses that need to be merged
60 * with any ports requested by ListenPort.
61 */
62struct queued_listenaddr {
63	char *addr;
64	int port; /* <=0 if unspecified */
65	char *rdomain;
66};
67
68/* Resolved listen addresses, grouped by optional routing domain */
69struct listenaddr {
70	char *rdomain;
71	struct addrinfo *addrs;
72};
73
74typedef struct {
75	u_int	num_ports;
76	u_int	ports_from_cmdline;
77	int	ports[MAX_PORTS];	/* Port number to listen on. */
78	struct queued_listenaddr *queued_listen_addrs;
79	u_int	num_queued_listens;
80	struct listenaddr *listen_addrs;
81	u_int	num_listen_addrs;
82	int	address_family;		/* Address family used by the server. */
83
84	char	*routing_domain;	/* Bind session to routing domain */
85
86	char   **host_key_files;	/* Files containing host keys. */
87	int	*host_key_file_userprovided; /* Key was specified by user. */
88	u_int	num_host_key_files;     /* Number of files for host keys. */
89	char   **host_cert_files;	/* Files containing host certs. */
90	u_int	num_host_cert_files;	/* Number of files for host certs. */
91
92	char   *host_key_agent;		/* ssh-agent socket for host keys. */
93	char   *pid_file;		/* Where to put our pid */
94	char   *moduli_file;		/* moduli file for DH-GEX */
95	int     login_grace_time;	/* Disconnect if no auth in this time
96					 * (sec). */
97	int     permit_root_login;	/* PERMIT_*, see above */
98	int     ignore_rhosts;	/* Ignore .rhosts and .shosts. */
99	int     ignore_user_known_hosts;	/* Ignore ~/.ssh/known_hosts
100						 * for RhostsRsaAuth */
101	int     print_motd;	/* If true, print /etc/motd. */
102	int	print_lastlog;	/* If true, print lastlog */
103	int     x11_forwarding;	/* If true, permit inet (spoofing) X11 fwd. */
104	int     x11_display_offset;	/* What DISPLAY number to start
105					 * searching at */
106	int     x11_use_localhost;	/* If true, use localhost for fake X11 server. */
107	char   *xauth_location;	/* Location of xauth program */
108	int	permit_tty;	/* If false, deny pty allocation */
109	int	permit_user_rc;	/* If false, deny ~/.ssh/rc execution */
110	int     strict_modes;	/* If true, require string home dir modes. */
111	int     tcp_keep_alive;	/* If true, set SO_KEEPALIVE. */
112	int	ip_qos_interactive;	/* IP ToS/DSCP/class for interactive */
113	int	ip_qos_bulk;		/* IP ToS/DSCP/class for bulk traffic */
114	char   *ciphers;	/* Supported SSH2 ciphers. */
115	char   *macs;		/* Supported SSH2 macs. */
116	char   *kex_algorithms;	/* SSH2 kex methods in order of preference. */
117	struct ForwardOptions fwd_opts;	/* forwarding options */
118	SyslogFacility log_facility;	/* Facility for system logging. */
119	LogLevel log_level;	/* Level for system logging. */
120	u_int	num_log_verbose;	/* Verbose log overrides */
121	char	**log_verbose;
122	int     hostbased_authentication;	/* If true, permit ssh2 hostbased auth */
123	int     hostbased_uses_name_from_packet_only; /* experimental */
124	char   *hostbased_accepted_algos; /* Algos allowed for hostbased */
125	char   *hostkeyalgorithms;	/* SSH2 server key types */
126	char   *ca_sign_algorithms;	/* Allowed CA signature algorithms */
127	int     pubkey_authentication;	/* If true, permit ssh2 pubkey authentication. */
128	char   *pubkey_accepted_algos;	/* Signature algos allowed for pubkey */
129	int	pubkey_auth_options;	/* -1 or mask of PUBKEYAUTH_* flags */
130	int     kerberos_authentication;	/* If true, permit Kerberos
131						 * authentication. */
132	int     kerberos_or_local_passwd;	/* If true, permit kerberos
133						 * and any other password
134						 * authentication mechanism,
135						 * such as SecurID or
136						 * /etc/passwd */
137	int     kerberos_ticket_cleanup;	/* If true, destroy ticket
138						 * file on logout. */
139	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
140						 * authenticated with Kerberos. */
141	int     gss_authentication;	/* If true, permit GSSAPI authentication */
142	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
143	int     gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
144	int     password_authentication;	/* If true, permit password
145						 * authentication. */
146	int     kbd_interactive_authentication;	/* If true, permit */
147	int     permit_empty_passwd;	/* If false, do not permit empty
148					 * passwords. */
149	int     permit_user_env;	/* If true, read ~/.ssh/environment */
150	char   *permit_user_env_allowlist; /* pattern-list of allowed env names */
151	int     compression;	/* If true, compression is allowed */
152	int	allow_tcp_forwarding; /* One of FORWARD_* */
153	int	allow_streamlocal_forwarding; /* One of FORWARD_* */
154	int	allow_agent_forwarding;
155	int	disable_forwarding;
156	u_int num_allow_users;
157	char   **allow_users;
158	u_int num_deny_users;
159	char   **deny_users;
160	u_int num_allow_groups;
161	char   **allow_groups;
162	u_int num_deny_groups;
163	char   **deny_groups;
164
165	u_int num_subsystems;
166	char   **subsystem_name;
167	char   **subsystem_command;
168	char   **subsystem_args;
169
170	u_int num_accept_env;
171	char   **accept_env;
172	u_int num_setenv;
173	char   **setenv;
174
175	int	max_startups_begin;
176	int	max_startups_rate;
177	int	max_startups;
178	int	per_source_max_startups;
179	int	per_source_masklen_ipv4;
180	int	per_source_masklen_ipv6;
181	int	max_authtries;
182	int	max_sessions;
183	char   *banner;			/* SSH-2 banner message */
184	int	use_dns;
185	int	client_alive_interval;	/*
186					 * poke the client this often to
187					 * see if it's still there
188					 */
189	int	client_alive_count_max;	/*
190					 * If the client is unresponsive
191					 * for this many intervals above,
192					 * disconnect the session
193					 */
194
195	u_int	num_authkeys_files;	/* Files containing public keys */
196	char   **authorized_keys_files;
197
198	char   *adm_forced_command;
199
200	int	use_pam;		/* Enable auth via PAM */
201
202	int	permit_tun;
203
204	char   **permitted_opens;	/* May also be one of PERMITOPEN_* */
205	u_int   num_permitted_opens;
206	char   **permitted_listens; /* May also be one of PERMITOPEN_* */
207	u_int   num_permitted_listens;
208
209	char   *chroot_directory;
210	char   *revoked_keys_file;
211	char   *trusted_user_ca_keys;
212	char   *authorized_keys_command;
213	char   *authorized_keys_command_user;
214	char   *authorized_principals_file;
215	char   *authorized_principals_command;
216	char   *authorized_principals_command_user;
217
218	int64_t rekey_limit;
219	int	rekey_interval;
220
221	char   *version_addendum;	/* Appended to SSH banner */
222
223	u_int	num_auth_methods;
224	char   **auth_methods;
225
226	int	fingerprint_hash;
227	int	expose_userauth_info;
228	u_int64_t timing_secret;
229	char   *sk_provider;
230	int	required_rsa_size;	/* minimum size of RSA keys */
231
232	char	**channel_timeouts;	/* inactivity timeout by channel type */
233	u_int	num_channel_timeouts;
234
235	int	unused_connection_timeout;
236
237	int	use_blacklist;
238}       ServerOptions;
239
240/* Information about the incoming connection as used by Match */
241struct connection_info {
242	const char *user;
243	const char *host;	/* possibly resolved hostname */
244	const char *address;	/* remote address */
245	const char *laddress;	/* local address */
246	int lport;		/* local port */
247	const char *rdomain;	/* routing domain if available */
248	int test;		/* test mode, allow some attributes to be
249				 * unspecified */
250};
251
252/* List of included files for re-exec from the parsed configuration */
253struct include_item {
254	char *selector;
255	char *filename;
256	struct sshbuf *contents;
257	TAILQ_ENTRY(include_item) entry;
258};
259TAILQ_HEAD(include_list, include_item);
260
261
262/*
263 * These are string config options that must be copied between the
264 * Match sub-config and the main config, and must be sent from the
265 * privsep child to the privsep master. We use a macro to ensure all
266 * the options are copied and the copies are done in the correct order.
267 *
268 * NB. an option must appear in servconf.c:copy_set_server_options() or
269 * COPY_MATCH_STRING_OPTS here but never both.
270 */
271#define COPY_MATCH_STRING_OPTS() do { \
272		M_CP_STROPT(banner); \
273		M_CP_STROPT(trusted_user_ca_keys); \
274		M_CP_STROPT(revoked_keys_file); \
275		M_CP_STROPT(authorized_keys_command); \
276		M_CP_STROPT(authorized_keys_command_user); \
277		M_CP_STROPT(authorized_principals_file); \
278		M_CP_STROPT(authorized_principals_command); \
279		M_CP_STROPT(authorized_principals_command_user); \
280		M_CP_STROPT(hostbased_accepted_algos); \
281		M_CP_STROPT(pubkey_accepted_algos); \
282		M_CP_STROPT(ca_sign_algorithms); \
283		M_CP_STROPT(routing_domain); \
284		M_CP_STROPT(permit_user_env_allowlist); \
285		M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
286		M_CP_STRARRAYOPT(allow_users, num_allow_users); \
287		M_CP_STRARRAYOPT(deny_users, num_deny_users); \
288		M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
289		M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
290		M_CP_STRARRAYOPT(accept_env, num_accept_env); \
291		M_CP_STRARRAYOPT(setenv, num_setenv); \
292		M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
293		M_CP_STRARRAYOPT(permitted_opens, num_permitted_opens); \
294		M_CP_STRARRAYOPT(permitted_listens, num_permitted_listens); \
295		M_CP_STRARRAYOPT(channel_timeouts, num_channel_timeouts); \
296		M_CP_STRARRAYOPT(log_verbose, num_log_verbose); \
297		M_CP_STRARRAYOPT(subsystem_name, num_subsystems); \
298		M_CP_STRARRAYOPT(subsystem_command, num_subsystems); \
299		M_CP_STRARRAYOPT(subsystem_args, num_subsystems); \
300	} while (0)
301
302struct connection_info *get_connection_info(struct ssh *, int, int);
303void	 initialize_server_options(ServerOptions *);
304void	 fill_default_server_options(ServerOptions *);
305int	 process_server_config_line(ServerOptions *, char *, const char *, int,
306	    int *, struct connection_info *, struct include_list *includes);
307void	 process_permitopen(struct ssh *ssh, ServerOptions *options);
308void	 process_channel_timeouts(struct ssh *ssh, ServerOptions *);
309void	 load_server_config(const char *, struct sshbuf *);
310void	 parse_server_config(ServerOptions *, const char *, struct sshbuf *,
311	    struct include_list *includes, struct connection_info *, int);
312void	 parse_server_match_config(ServerOptions *,
313	    struct include_list *includes, struct connection_info *);
314int	 parse_server_match_testspec(struct connection_info *, char *);
315int	 server_match_spec_complete(struct connection_info *);
316void	 servconf_merge_subsystems(ServerOptions *, ServerOptions *);
317void	 copy_set_server_options(ServerOptions *, ServerOptions *, int);
318void	 dump_config(ServerOptions *);
319char	*derelativise_path(const char *);
320void	 servconf_add_hostkey(const char *, const int,
321	    ServerOptions *, const char *path, int);
322void	 servconf_add_hostcert(const char *, const int,
323	    ServerOptions *, const char *path);
324
325#endif				/* SERVCONF_H */
326