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1 /* $OpenBSD: servconf.h,v 1.123 2016/11/30 03:00:05 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 #define MAX_PORTS		256	/* Max # ports. */
20 
21 #define MAX_ALLOW_USERS		256	/* Max # users on allow list. */
22 #define MAX_DENY_USERS		256	/* Max # users on deny list. */
23 #define MAX_ALLOW_GROUPS	256	/* Max # groups on allow list. */
24 #define MAX_DENY_GROUPS		256	/* Max # groups on deny list. */
25 #define MAX_SUBSYSTEMS		256	/* Max # subsystems. */
26 #define MAX_HOSTKEYS		256	/* Max # hostkeys. */
27 #define MAX_HOSTCERTS		256	/* Max # host certificates. */
28 #define MAX_ACCEPT_ENV		256	/* Max # of env vars. */
29 #define MAX_MATCH_GROUPS	256	/* Max # of groups for Match. */
30 #define MAX_AUTHKEYS_FILES	256	/* Max # of authorized_keys files. */
31 #define MAX_AUTH_METHODS	256	/* Max # of AuthenticationMethods. */
32 
33 /* permit_root_login */
34 #define	PERMIT_NOT_SET		-1
35 #define	PERMIT_NO		0
36 #define	PERMIT_FORCED_ONLY	1
37 #define	PERMIT_NO_PASSWD	2
38 #define	PERMIT_YES		3
39 
40 /* use_privsep */
41 #define PRIVSEP_OFF		0
42 #define PRIVSEP_ON		1
43 #define PRIVSEP_NOSANDBOX	2
44 
45 /* AllowTCPForwarding */
46 #define FORWARD_DENY		0
47 #define FORWARD_REMOTE		(1)
48 #define FORWARD_LOCAL		(1<<1)
49 #define FORWARD_ALLOW		(FORWARD_REMOTE|FORWARD_LOCAL)
50 
51 #define DEFAULT_AUTH_FAIL_MAX	6	/* Default for MaxAuthTries */
52 #define DEFAULT_SESSIONS_MAX	10	/* Default for MaxSessions */
53 
54 /* Magic name for internal sftp-server */
55 #define INTERNAL_SFTP_NAME	"internal-sftp"
56 
57 typedef struct {
58 	u_int	num_ports;
59 	u_int	ports_from_cmdline;
60 	int	ports[MAX_PORTS];	/* Port number to listen on. */
61 	u_int	num_queued_listens;
62 	char   **queued_listen_addrs;
63 	int    *queued_listen_ports;
64 	struct addrinfo *listen_addrs;	/* Addresses on which the server listens. */
65 	int     address_family;		/* Address family used by the server. */
66 	char   *host_key_files[MAX_HOSTKEYS];	/* Files containing host keys. */
67 	int     num_host_key_files;     /* Number of files for host keys. */
68 	char   *host_cert_files[MAX_HOSTCERTS];	/* Files containing host certs. */
69 	int     num_host_cert_files;     /* Number of files for host certs. */
70 	char   *host_key_agent;		 /* ssh-agent socket for host keys. */
71 	char   *pid_file;	/* Where to put our pid */
72 	int     login_grace_time;	/* Disconnect if no auth in this time
73 					 * (sec). */
74 	int     permit_root_login;	/* PERMIT_*, see above */
75 	int     ignore_rhosts;	/* Ignore .rhosts and .shosts. */
76 	int     ignore_user_known_hosts;	/* Ignore ~/.ssh/known_hosts
77 						 * for RhostsRsaAuth */
78 	int     print_motd;	/* If true, print /etc/motd. */
79 	int	print_lastlog;	/* If true, print lastlog */
80 	int     x11_forwarding;	/* If true, permit inet (spoofing) X11 fwd. */
81 	int     x11_display_offset;	/* What DISPLAY number to start
82 					 * searching at */
83 	int     x11_use_localhost;	/* If true, use localhost for fake X11 server. */
84 	char   *xauth_location;	/* Location of xauth program */
85 	int	permit_tty;	/* If false, deny pty allocation */
86 	int	permit_user_rc;	/* If false, deny ~/.ssh/rc execution */
87 	int     strict_modes;	/* If true, require string home dir modes. */
88 	int     tcp_keep_alive;	/* If true, set SO_KEEPALIVE. */
89 	int	ip_qos_interactive;	/* IP ToS/DSCP/class for interactive */
90 	int	ip_qos_bulk;		/* IP ToS/DSCP/class for bulk traffic */
91 	char   *ciphers;	/* Supported SSH2 ciphers. */
92 	char   *macs;		/* Supported SSH2 macs. */
93 	char   *kex_algorithms;	/* SSH2 kex methods in order of preference. */
94 	struct ForwardOptions fwd_opts;	/* forwarding options */
95 	SyslogFacility log_facility;	/* Facility for system logging. */
96 	LogLevel log_level;	/* Level for system logging. */
97 	int     hostbased_authentication;	/* If true, permit ssh2 hostbased auth */
98 	int     hostbased_uses_name_from_packet_only; /* experimental */
99 	char   *hostbased_key_types;	/* Key types allowed for hostbased */
100 	char   *hostkeyalgorithms;	/* SSH2 server key types */
101 	int     pubkey_authentication;	/* If true, permit ssh2 pubkey authentication. */
102 	char   *pubkey_key_types;	/* Key types allowed for public key */
103 	int     kerberos_authentication;	/* If true, permit Kerberos
104 						 * authentication. */
105 	int     kerberos_or_local_passwd;	/* If true, permit kerberos
106 						 * and any other password
107 						 * authentication mechanism,
108 						 * such as SecurID or
109 						 * /etc/passwd */
110 	int     kerberos_ticket_cleanup;	/* If true, destroy ticket
111 						 * file on logout. */
112 	int     kerberos_get_afs_token;		/* If true, try to get AFS token if
113 						 * authenticated with Kerberos. */
114 	int     gss_authentication;	/* If true, permit GSSAPI authentication */
115 	int     gss_cleanup_creds;	/* If true, destroy cred cache on logout */
116 	int     gss_strict_acceptor;	/* If true, restrict the GSSAPI acceptor name */
117 	int     password_authentication;	/* If true, permit password
118 						 * authentication. */
119 	int     kbd_interactive_authentication;	/* If true, permit */
120 	int     challenge_response_authentication;
121 	int     permit_empty_passwd;	/* If false, do not permit empty
122 					 * passwords. */
123 	int     permit_user_env;	/* If true, read ~/.ssh/environment */
124 	int     compression;	/* If true, compression is allowed */
125 	int	allow_tcp_forwarding; /* One of FORWARD_* */
126 	int	allow_streamlocal_forwarding; /* One of FORWARD_* */
127 	int	allow_agent_forwarding;
128 	int	disable_forwarding;
129 	u_int num_allow_users;
130 	char   *allow_users[MAX_ALLOW_USERS];
131 	u_int num_deny_users;
132 	char   *deny_users[MAX_DENY_USERS];
133 	u_int num_allow_groups;
134 	char   *allow_groups[MAX_ALLOW_GROUPS];
135 	u_int num_deny_groups;
136 	char   *deny_groups[MAX_DENY_GROUPS];
137 
138 	u_int num_subsystems;
139 	char   *subsystem_name[MAX_SUBSYSTEMS];
140 	char   *subsystem_command[MAX_SUBSYSTEMS];
141 	char   *subsystem_args[MAX_SUBSYSTEMS];
142 
143 	u_int num_accept_env;
144 	char   *accept_env[MAX_ACCEPT_ENV];
145 
146 	int	max_startups_begin;
147 	int	max_startups_rate;
148 	int	max_startups;
149 	int	max_authtries;
150 	int	max_sessions;
151 	char   *banner;			/* SSH-2 banner message */
152 	int	use_dns;
153 	int	client_alive_interval;	/*
154 					 * poke the client this often to
155 					 * see if it's still there
156 					 */
157 	int	client_alive_count_max;	/*
158 					 * If the client is unresponsive
159 					 * for this many intervals above,
160 					 * disconnect the session
161 					 */
162 
163 	u_int num_authkeys_files;	/* Files containing public keys */
164 	char   *authorized_keys_files[MAX_AUTHKEYS_FILES];
165 
166 	char   *adm_forced_command;
167 
168 	int	use_pam;		/* Enable auth via PAM */
169 
170 	int	permit_tun;
171 
172 	int	num_permitted_opens;
173 
174 	char   *chroot_directory;
175 	char   *revoked_keys_file;
176 	char   *trusted_user_ca_keys;
177 	char   *authorized_keys_command;
178 	char   *authorized_keys_command_user;
179 	char   *authorized_principals_file;
180 	char   *authorized_principals_command;
181 	char   *authorized_principals_command_user;
182 
183 	int64_t rekey_limit;
184 	int	rekey_interval;
185 
186 	char   *version_addendum;	/* Appended to SSH banner */
187 
188 	u_int	num_auth_methods;
189 	char   *auth_methods[MAX_AUTH_METHODS];
190 
191 	int	fingerprint_hash;
192 }       ServerOptions;
193 
194 /* Information about the incoming connection as used by Match */
195 struct connection_info {
196 	const char *user;
197 	const char *host;	/* possibly resolved hostname */
198 	const char *address; 	/* remote address */
199 	const char *laddress;	/* local address */
200 	int lport;		/* local port */
201 };
202 
203 
204 /*
205  * These are string config options that must be copied between the
206  * Match sub-config and the main config, and must be sent from the
207  * privsep slave to the privsep master. We use a macro to ensure all
208  * the options are copied and the copies are done in the correct order.
209  *
210  * NB. an option must appear in servconf.c:copy_set_server_options() or
211  * COPY_MATCH_STRING_OPTS here but never both.
212  */
213 #define COPY_MATCH_STRING_OPTS() do { \
214 		M_CP_STROPT(banner); \
215 		M_CP_STROPT(trusted_user_ca_keys); \
216 		M_CP_STROPT(revoked_keys_file); \
217 		M_CP_STROPT(authorized_keys_command); \
218 		M_CP_STROPT(authorized_keys_command_user); \
219 		M_CP_STROPT(authorized_principals_file); \
220 		M_CP_STROPT(authorized_principals_command); \
221 		M_CP_STROPT(authorized_principals_command_user); \
222 		M_CP_STROPT(hostbased_key_types); \
223 		M_CP_STROPT(pubkey_key_types); \
224 		M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
225 		M_CP_STRARRAYOPT(allow_users, num_allow_users); \
226 		M_CP_STRARRAYOPT(deny_users, num_deny_users); \
227 		M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
228 		M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
229 		M_CP_STRARRAYOPT(accept_env, num_accept_env); \
230 		M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
231 	} while (0)
232 
233 struct connection_info *get_connection_info(int, int);
234 void	 initialize_server_options(ServerOptions *);
235 void	 fill_default_server_options(ServerOptions *);
236 int	 process_server_config_line(ServerOptions *, char *, const char *, int,
237 	     int *, struct connection_info *);
238 void	 load_server_config(const char *, Buffer *);
239 void	 parse_server_config(ServerOptions *, const char *, Buffer *,
240 	     struct connection_info *);
241 void	 parse_server_match_config(ServerOptions *, struct connection_info *);
242 int	 parse_server_match_testspec(struct connection_info *, char *);
243 int	 server_match_spec_complete(struct connection_info *);
244 void	 copy_set_server_options(ServerOptions *, ServerOptions *, int);
245 void	 dump_config(ServerOptions *);
246 char	*derelativise_path(const char *);
247 
248 #endif				/* SERVCONF_H */
249