1/*	$NetBSD: servconf.h,v 1.30 2023/10/25 20:19:57 christos Exp $	*/
2/* $OpenBSD: servconf.h,v 1.160 2023/09/06 23:35:35 djm Exp $ */
3
4/*
5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7 *                    All rights reserved
8 * Definitions for server configuration data and for the functions reading it.
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 SERVCONF_H
18#define SERVCONF_H
19
20#ifdef WITH_LDAP_PUBKEY
21#include "ldapauth.h"
22#endif
23
24#include <sys/queue.h>
25
26#define MAX_PORTS		256	/* Max # ports. */
27
28/* permit_root_login */
29#define	PERMIT_NOT_SET		-1
30#define	PERMIT_NO		0
31#define	PERMIT_FORCED_ONLY	1
32#define	PERMIT_NO_PASSWD	2
33#define	PERMIT_YES		3
34
35/* use_privsep */
36#define PRIVSEP_OFF		0
37#define PRIVSEP_ON		1
38#define PRIVSEP_NOSANDBOX	2
39
40/* PermitOpen */
41#define PERMITOPEN_ANY		0
42#define PERMITOPEN_NONE		-2
43
44/* IgnoreRhosts */
45#define IGNORE_RHOSTS_NO	0
46#define IGNORE_RHOSTS_YES	1
47#define IGNORE_RHOSTS_SHOSTS	2
48
49#define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */
50#define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */
51
52/* Magic name for internal sftp-server */
53#define INTERNAL_SFTP_NAME	"internal-sftp"
54
55/* PubkeyAuthOptions flags */
56#define PUBKEYAUTH_TOUCH_REQUIRED	(1)
57#define PUBKEYAUTH_VERIFY_REQUIRED	(1<<1)
58
59struct ssh;
60struct fwd_perm_list;
61
62/*
63 * Used to store addresses from ListenAddr directives. These may be
64 * incomplete, as they may specify addresses that need to be merged
65 * with any ports requested by ListenPort.
66 */
67struct queued_listenaddr {
68	char *addr;
69	int port; /* <=0 if unspecified */
70	char *rdomain;
71};
72
73/* Resolved listen addresses, grouped by optional routing domain */
74struct listenaddr {
75	char *rdomain;
76	struct addrinfo *addrs;
77};
78
79typedef struct {
80	u_int	num_ports;
81	u_int	ports_from_cmdline;
82	int	ports[MAX_PORTS];	/* Port number to listen on. */
83	struct queued_listenaddr *queued_listen_addrs;
84	u_int	num_queued_listens;
85	struct listenaddr *listen_addrs;
86	u_int	num_listen_addrs;
87	int	address_family;		/* Address family used by the server. */
88
89	char	*routing_domain;	/* Bind session to routing domain */
90
91	char   **host_key_files;	/* Files containing host keys. */
92	int	*host_key_file_userprovided; /* Key was specified by user. */
93	u_int	num_host_key_files;     /* Number of files for host keys. */
94	char   **host_cert_files;	/* Files containing host certs. */
95	u_int	num_host_cert_files;	/* Number of files for host certs. */
96
97	char   *host_key_agent;		/* ssh-agent socket for host keys. */
98	char   *pid_file;		/* Where to put our pid */
99	char   *moduli_file;		/* moduli file for DH-GEX */
100	int     login_grace_time;	/* Disconnect if no auth in this time
101					 * (sec). */
102	int     permit_root_login;	/* PERMIT_*, see above */
103	int     ignore_rhosts;	/* Ignore .rhosts and .shosts. */
104	int     ignore_root_rhosts;	/* Ignore .rhosts and .shosts for root;
105					   defaults to ignore_rhosts if not
106					   given. */
107	int     ignore_user_known_hosts;	/* Ignore ~/.ssh/known_hosts
108						 * for RhostsRsaAuth */
109	int     print_motd;	/* If true, print /etc/motd. */
110	int	print_lastlog;	/* If true, print lastlog */
111	int     x11_forwarding;	/* If true, permit inet (spoofing) X11 fwd. */
112	int     x11_display_offset;	/* What DISPLAY number to start
113					 * searching at */
114	int     x11_use_localhost;	/* If true, use localhost for fake X11 server. */
115	char   *xauth_location;	/* Location of xauth program */
116	int	permit_tty;	/* If false, deny pty allocation */
117	int	permit_user_rc;	/* If false, deny ~/.ssh/rc execution */
118	int     strict_modes;	/* If true, require string home dir modes. */
119	int     tcp_keep_alive;	/* If true, set SO_KEEPALIVE. */
120	int	ip_qos_interactive;	/* IP ToS/DSCP/class for interactive */
121	int	ip_qos_bulk;		/* IP ToS/DSCP/class for bulk traffic */
122	char   *ciphers;	/* Supported SSH2 ciphers. */
123	char   *macs;		/* Supported SSH2 macs. */
124	char   *kex_algorithms;	/* SSH2 kex methods in order of preference. */
125	struct ForwardOptions fwd_opts;	/* forwarding options */
126	SyslogFacility log_facility;	/* Facility for system logging. */
127	LogLevel log_level;	/* Level for system logging. */
128	u_int	num_log_verbose;	/* Verbose log overrides */
129	char	**log_verbose;
130	int     hostbased_authentication;	/* If true, permit ssh2 hostbased auth */
131	int     hostbased_uses_name_from_packet_only; /* experimental */
132	char   *hostbased_accepted_algos; /* Algos allowed for hostbased */
133	char   *hostkeyalgorithms;	/* SSH2 server key types */
134	char   *ca_sign_algorithms;	/* Allowed CA signature algorithms */
135	int     pubkey_authentication;	/* If true, permit ssh2 pubkey authentication. */
136	char   *pubkey_accepted_algos;	/* Signature algos allowed for pubkey */
137	int	pubkey_auth_options;	/* -1 or mask of PUBKEYAUTH_* flags */
138	int     kerberos_authentication;	/* If true, permit Kerberos
139						 * authentication. */
140	int     kerberos_or_local_passwd;	/* If true, permit kerberos
141						 * and any other password
142						 * authentication mechanism,
143						 * such as SecurID or
144						 * /etc/passwd */
145	int     kerberos_ticket_cleanup;	/* If true, destroy ticket
146						 * file on logout. */
147	int	kerberos_tgt_passing;		/* If true, permit Kerberos TGT
148						 * passing. */
149	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
150						 * authenticated with Kerberos. */
151#ifdef AFS
152	int     afs_token_passing;      /* If true, permit AFS token passing. */
153#endif
154	int     gss_authentication;	/* If true, permit GSSAPI authentication */
155	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
156	int     gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
157	int     password_authentication;	/* If true, permit password
158						 * authentication. */
159	int     kbd_interactive_authentication;	/* If true, permit */
160	int     permit_empty_passwd;	/* If false, do not permit empty
161					 * passwords. */
162	int     permit_user_env;	/* If true, read ~/.ssh/environment */
163	char   *permit_user_env_allowlist; /* pattern-list of allowed env names */
164	int     compression;	/* If true, compression is allowed */
165	int	allow_tcp_forwarding; /* One of FORWARD_* */
166	int	allow_streamlocal_forwarding; /* One of FORWARD_* */
167	int	allow_agent_forwarding;
168	int	disable_forwarding;
169	u_int num_allow_users;
170	char   **allow_users;
171	u_int num_deny_users;
172	char   **deny_users;
173	u_int num_allow_groups;
174	char   **allow_groups;
175	u_int num_deny_groups;
176	char   **deny_groups;
177
178	u_int num_subsystems;
179	char   **subsystem_name;
180	char   **subsystem_command;
181	char   **subsystem_args;
182
183	u_int num_accept_env;
184	char   **accept_env;
185	u_int num_setenv;
186	char   **setenv;
187
188	int	max_startups_begin;
189	int	max_startups_rate;
190	int	max_startups;
191	int	per_source_max_startups;
192	int	per_source_masklen_ipv4;
193	int	per_source_masklen_ipv6;
194	int	max_authtries;
195	int	max_sessions;
196	char   *banner;			/* SSH-2 banner message */
197	int	use_dns;
198	int	client_alive_interval;	/*
199					 * poke the client this often to
200					 * see if it's still there
201					 */
202	int	client_alive_count_max;	/*
203					 * If the client is unresponsive
204					 * for this many intervals above,
205					 * disconnect the session
206					 */
207
208	u_int	num_authkeys_files;	/* Files containing public keys */
209	char   **authorized_keys_files;
210
211	int	use_pam;		/* Enable auth via PAM */
212	int     none_enabled;           /* enable NONE cipher switch */
213	int     tcp_rcv_buf_poll;       /* poll tcp rcv window in autotuning kernels*/
214	int	hpn_disabled;		/* disable hpn functionality. false by default */
215	int	hpn_buffer_size;	/* set the hpn buffer size - default 3MB */
216
217	char   *adm_forced_command;
218
219	int	permit_tun;
220#ifdef WITH_LDAP_PUBKEY
221        ldap_opt_t lpk;
222#endif
223
224	char   **permitted_opens;	/* May also be one of PERMITOPEN_* */
225	u_int   num_permitted_opens;
226	char   **permitted_listens; /* May also be one of PERMITOPEN_* */
227	u_int   num_permitted_listens;
228
229	char   *chroot_directory;
230	char   *revoked_keys_file;
231	char   *trusted_user_ca_keys;
232	char   *authorized_keys_command;
233	char   *authorized_keys_command_user;
234	char   *authorized_principals_file;
235	char   *authorized_principals_command;
236	char   *authorized_principals_command_user;
237
238	int64_t rekey_limit;
239	int	rekey_interval;
240
241	char   *version_addendum;	/* Appended to SSH banner */
242
243	u_int	num_auth_methods;
244	char   **auth_methods;
245
246	int	fingerprint_hash;
247	int	expose_userauth_info;
248	u_int64_t timing_secret;
249	char   *sk_provider;
250	int	required_rsa_size;	/* minimum size of RSA keys */
251
252	char	**channel_timeouts;	/* inactivity timeout by channel type */
253	u_int	num_channel_timeouts;
254
255	int	unused_connection_timeout;
256}       ServerOptions;
257
258/* Information about the incoming connection as used by Match */
259struct connection_info {
260	const char *user;
261	const char *host;	/* possibly resolved hostname */
262	const char *address;	/* remote address */
263	const char *laddress;	/* local address */
264	int lport;		/* local port */
265	const char *rdomain;	/* routing domain if available */
266	int test;		/* test mode, allow some attributes to be
267				 * unspecified */
268};
269
270/* List of included files for re-exec from the parsed configuration */
271struct include_item {
272	char *selector;
273	char *filename;
274	struct sshbuf *contents;
275	TAILQ_ENTRY(include_item) entry;
276};
277TAILQ_HEAD(include_list, include_item);
278
279
280/*
281 * These are string config options that must be copied between the
282 * Match sub-config and the main config, and must be sent from the
283 * privsep child to the privsep master. We use a macro to ensure all
284 * the options are copied and the copies are done in the correct order.
285 *
286 * NB. an option must appear in servconf.c:copy_set_server_options() or
287 * COPY_MATCH_STRING_OPTS here but never both.
288 */
289#define COPY_MATCH_STRING_OPTS() do { \
290		M_CP_STROPT(banner); \
291		M_CP_STROPT(trusted_user_ca_keys); \
292		M_CP_STROPT(revoked_keys_file); \
293		M_CP_STROPT(authorized_keys_command); \
294		M_CP_STROPT(authorized_keys_command_user); \
295		M_CP_STROPT(authorized_principals_file); \
296		M_CP_STROPT(authorized_principals_command); \
297		M_CP_STROPT(authorized_principals_command_user); \
298		M_CP_STROPT(hostbased_accepted_algos); \
299		M_CP_STROPT(pubkey_accepted_algos); \
300		M_CP_STROPT(ca_sign_algorithms); \
301		M_CP_STROPT(routing_domain); \
302		M_CP_STROPT(permit_user_env_allowlist); \
303		M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
304		M_CP_STRARRAYOPT(allow_users, num_allow_users); \
305		M_CP_STRARRAYOPT(deny_users, num_deny_users); \
306		M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
307		M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
308		M_CP_STRARRAYOPT(accept_env, num_accept_env); \
309		M_CP_STRARRAYOPT(setenv, num_setenv); \
310		M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
311		M_CP_STRARRAYOPT(permitted_opens, num_permitted_opens); \
312		M_CP_STRARRAYOPT(permitted_listens, num_permitted_listens); \
313		M_CP_STRARRAYOPT(channel_timeouts, num_channel_timeouts); \
314		M_CP_STRARRAYOPT(log_verbose, num_log_verbose); \
315		M_CP_STRARRAYOPT(subsystem_name, num_subsystems); \
316		M_CP_STRARRAYOPT(subsystem_command, num_subsystems); \
317		M_CP_STRARRAYOPT(subsystem_args, num_subsystems); \
318	} while (0)
319
320struct connection_info *get_connection_info(struct ssh *, int, int);
321void	 initialize_server_options(ServerOptions *);
322void	 fill_default_server_options(ServerOptions *);
323int	 process_server_config_line(ServerOptions *, char *, const char *, int,
324	    int *, struct connection_info *, struct include_list *includes);
325void	 process_permitopen(struct ssh *ssh, ServerOptions *options);
326void	 process_channel_timeouts(struct ssh *ssh, ServerOptions *);
327void	 load_server_config(const char *, struct sshbuf *);
328void	 parse_server_config(ServerOptions *, const char *, struct sshbuf *,
329	    struct include_list *includes, struct connection_info *, int);
330void	 parse_server_match_config(ServerOptions *,
331	    struct include_list *includes, struct connection_info *);
332int	 parse_server_match_testspec(struct connection_info *, char *);
333int	 server_match_spec_complete(struct connection_info *);
334void	 servconf_merge_subsystems(ServerOptions *, ServerOptions *);
335void	 copy_set_server_options(ServerOptions *, ServerOptions *, int);
336void	 dump_config(ServerOptions *);
337char	*derelativise_path(const char *);
338void	 servconf_add_hostkey(const char *, const int,
339	    ServerOptions *, const char *path, int);
340void	 servconf_add_hostcert(const char *, const int,
341	    ServerOptions *, const char *path);
342
343#endif				/* SERVCONF_H */
344