1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
|
/* $OpenBSD: servconf.h,v 1.160 2023/09/06 23:35:35 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Definitions for server configuration data and for the functions reading it.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#ifndef SERVCONF_H
#define SERVCONF_H
#include <openbsd-compat/sys-queue.h>
#define MAX_PORTS 256 /* Max # ports. */
/* permit_root_login */
#define PERMIT_NOT_SET -1
#define PERMIT_NO 0
#define PERMIT_FORCED_ONLY 1
#define PERMIT_NO_PASSWD 2
#define PERMIT_YES 3
/* use_privsep */
#define PRIVSEP_OFF 0
#define PRIVSEP_ON 1
#define PRIVSEP_NOSANDBOX 2
/* PermitOpen */
#define PERMITOPEN_ANY 0
#define PERMITOPEN_NONE -2
/* IgnoreRhosts */
#define IGNORE_RHOSTS_NO 0
#define IGNORE_RHOSTS_YES 1
#define IGNORE_RHOSTS_SHOSTS 2
#define DEFAULT_AUTH_FAIL_MAX 6 /* Default for MaxAuthTries */
#define DEFAULT_SESSIONS_MAX 10 /* Default for MaxSessions */
/* Magic name for internal sftp-server */
#define INTERNAL_SFTP_NAME "internal-sftp"
/* PubkeyAuthOptions flags */
#define PUBKEYAUTH_TOUCH_REQUIRED (1)
#define PUBKEYAUTH_VERIFY_REQUIRED (1<<1)
struct ssh;
struct fwd_perm_list;
/*
* Used to store addresses from ListenAddr directives. These may be
* incomplete, as they may specify addresses that need to be merged
* with any ports requested by ListenPort.
*/
struct queued_listenaddr {
char *addr;
int port; /* <=0 if unspecified */
char *rdomain;
};
/* Resolved listen addresses, grouped by optional routing domain */
struct listenaddr {
char *rdomain;
struct addrinfo *addrs;
};
typedef struct {
u_int num_ports;
u_int ports_from_cmdline;
int ports[MAX_PORTS]; /* Port number to listen on. */
struct queued_listenaddr *queued_listen_addrs;
u_int num_queued_listens;
struct listenaddr *listen_addrs;
u_int num_listen_addrs;
int address_family; /* Address family used by the server. */
char *routing_domain; /* Bind session to routing domain */
char **host_key_files; /* Files containing host keys. */
int *host_key_file_userprovided; /* Key was specified by user. */
u_int num_host_key_files; /* Number of files for host keys. */
char **host_cert_files; /* Files containing host certs. */
u_int num_host_cert_files; /* Number of files for host certs. */
char *host_key_agent; /* ssh-agent socket for host keys. */
char *pid_file; /* Where to put our pid */
char *moduli_file; /* moduli file for DH-GEX */
int login_grace_time; /* Disconnect if no auth in this time
* (sec). */
int permit_root_login; /* PERMIT_*, see above */
int ignore_rhosts; /* Ignore .rhosts and .shosts. */
int ignore_user_known_hosts; /* Ignore ~/.ssh/known_hosts
* for RhostsRsaAuth */
int print_motd; /* If true, print /etc/motd. */
int print_lastlog; /* If true, print lastlog */
int x11_forwarding; /* If true, permit inet (spoofing) X11 fwd. */
int x11_display_offset; /* What DISPLAY number to start
* searching at */
int x11_use_localhost; /* If true, use localhost for fake X11 server. */
char *xauth_location; /* Location of xauth program */
int permit_tty; /* If false, deny pty allocation */
int permit_user_rc; /* If false, deny ~/.ssh/rc execution */
int strict_modes; /* If true, require string home dir modes. */
int tcp_keep_alive; /* If true, set SO_KEEPALIVE. */
int ip_qos_interactive; /* IP ToS/DSCP/class for interactive */
int ip_qos_bulk; /* IP ToS/DSCP/class for bulk traffic */
char *ciphers; /* Supported SSH2 ciphers. */
char *macs; /* Supported SSH2 macs. */
char *kex_algorithms; /* SSH2 kex methods in order of preference. */
struct ForwardOptions fwd_opts; /* forwarding options */
SyslogFacility log_facility; /* Facility for system logging. */
LogLevel log_level; /* Level for system logging. */
u_int num_log_verbose; /* Verbose log overrides */
char **log_verbose;
int hostbased_authentication; /* If true, permit ssh2 hostbased auth */
int hostbased_uses_name_from_packet_only; /* experimental */
char *hostbased_accepted_algos; /* Algos allowed for hostbased */
char *hostkeyalgorithms; /* SSH2 server key types */
char *ca_sign_algorithms; /* Allowed CA signature algorithms */
int pubkey_authentication; /* If true, permit ssh2 pubkey authentication. */
char *pubkey_accepted_algos; /* Signature algos allowed for pubkey */
int pubkey_auth_options; /* -1 or mask of PUBKEYAUTH_* flags */
int kerberos_authentication; /* If true, permit Kerberos
* authentication. */
int kerberos_or_local_passwd; /* If true, permit kerberos
* and any other password
* authentication mechanism,
* such as SecurID or
* /etc/passwd */
int kerberos_ticket_cleanup; /* If true, destroy ticket
* file on logout. */
int kerberos_get_afs_token; /* If true, try to get AFS token if
* authenticated with Kerberos. */
int gss_authentication; /* If true, permit GSSAPI authentication */
int gss_cleanup_creds; /* If true, destroy cred cache on logout */
int gss_strict_acceptor; /* If true, restrict the GSSAPI acceptor name */
int password_authentication; /* If true, permit password
* authentication. */
int kbd_interactive_authentication; /* If true, permit */
int permit_empty_passwd; /* If false, do not permit empty
* passwords. */
int permit_user_env; /* If true, read ~/.ssh/environment */
char *permit_user_env_allowlist; /* pattern-list of allowed env names */
int compression; /* If true, compression is allowed */
int allow_tcp_forwarding; /* One of FORWARD_* */
int allow_streamlocal_forwarding; /* One of FORWARD_* */
int allow_agent_forwarding;
int disable_forwarding;
u_int num_allow_users;
char **allow_users;
u_int num_deny_users;
char **deny_users;
u_int num_allow_groups;
char **allow_groups;
u_int num_deny_groups;
char **deny_groups;
u_int num_subsystems;
char **subsystem_name;
char **subsystem_command;
char **subsystem_args;
u_int num_accept_env;
char **accept_env;
u_int num_setenv;
char **setenv;
int max_startups_begin;
int max_startups_rate;
int max_startups;
int per_source_max_startups;
int per_source_masklen_ipv4;
int per_source_masklen_ipv6;
int max_authtries;
int max_sessions;
char *banner; /* SSH-2 banner message */
int use_dns;
int client_alive_interval; /*
* poke the client this often to
* see if it's still there
*/
int client_alive_count_max; /*
* If the client is unresponsive
* for this many intervals above,
* disconnect the session
*/
u_int num_authkeys_files; /* Files containing public keys */
char **authorized_keys_files;
char *adm_forced_command;
int use_pam; /* Enable auth via PAM */
int permit_tun;
char **permitted_opens; /* May also be one of PERMITOPEN_* */
u_int num_permitted_opens;
char **permitted_listens; /* May also be one of PERMITOPEN_* */
u_int num_permitted_listens;
char *chroot_directory;
char *revoked_keys_file;
char *trusted_user_ca_keys;
char *authorized_keys_command;
char *authorized_keys_command_user;
char *authorized_principals_file;
char *authorized_principals_command;
char *authorized_principals_command_user;
int64_t rekey_limit;
int rekey_interval;
char *version_addendum; /* Appended to SSH banner */
u_int num_auth_methods;
char **auth_methods;
int fingerprint_hash;
int expose_userauth_info;
u_int64_t timing_secret;
char *sk_provider;
int required_rsa_size; /* minimum size of RSA keys */
char **channel_timeouts; /* inactivity timeout by channel type */
u_int num_channel_timeouts;
int unused_connection_timeout;
} ServerOptions;
/* Information about the incoming connection as used by Match */
struct connection_info {
const char *user;
const char *host; /* possibly resolved hostname */
const char *address; /* remote address */
const char *laddress; /* local address */
int lport; /* local port */
const char *rdomain; /* routing domain if available */
int test; /* test mode, allow some attributes to be
* unspecified */
};
/* List of included files for re-exec from the parsed configuration */
struct include_item {
char *selector;
char *filename;
struct sshbuf *contents;
TAILQ_ENTRY(include_item) entry;
};
TAILQ_HEAD(include_list, include_item);
/*
* These are string config options that must be copied between the
* Match sub-config and the main config, and must be sent from the
* privsep child to the privsep master. We use a macro to ensure all
* the options are copied and the copies are done in the correct order.
*
* NB. an option must appear in servconf.c:copy_set_server_options() or
* COPY_MATCH_STRING_OPTS here but never both.
*/
#define COPY_MATCH_STRING_OPTS() do { \
M_CP_STROPT(banner); \
M_CP_STROPT(trusted_user_ca_keys); \
M_CP_STROPT(revoked_keys_file); \
M_CP_STROPT(authorized_keys_command); \
M_CP_STROPT(authorized_keys_command_user); \
M_CP_STROPT(authorized_principals_file); \
M_CP_STROPT(authorized_principals_command); \
M_CP_STROPT(authorized_principals_command_user); \
M_CP_STROPT(hostbased_accepted_algos); \
M_CP_STROPT(pubkey_accepted_algos); \
M_CP_STROPT(ca_sign_algorithms); \
M_CP_STROPT(routing_domain); \
M_CP_STROPT(permit_user_env_allowlist); \
M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
M_CP_STRARRAYOPT(allow_users, num_allow_users); \
M_CP_STRARRAYOPT(deny_users, num_deny_users); \
M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
M_CP_STRARRAYOPT(accept_env, num_accept_env); \
M_CP_STRARRAYOPT(setenv, num_setenv); \
M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
M_CP_STRARRAYOPT(permitted_opens, num_permitted_opens); \
M_CP_STRARRAYOPT(permitted_listens, num_permitted_listens); \
M_CP_STRARRAYOPT(channel_timeouts, num_channel_timeouts); \
M_CP_STRARRAYOPT(log_verbose, num_log_verbose); \
M_CP_STRARRAYOPT(subsystem_name, num_subsystems); \
M_CP_STRARRAYOPT(subsystem_command, num_subsystems); \
M_CP_STRARRAYOPT(subsystem_args, num_subsystems); \
} while (0)
struct connection_info *get_connection_info(struct ssh *, int, int);
void initialize_server_options(ServerOptions *);
void fill_default_server_options(ServerOptions *);
int process_server_config_line(ServerOptions *, char *, const char *, int,
int *, struct connection_info *, struct include_list *includes);
void process_permitopen(struct ssh *ssh, ServerOptions *options);
void process_channel_timeouts(struct ssh *ssh, ServerOptions *);
void load_server_config(const char *, struct sshbuf *);
void parse_server_config(ServerOptions *, const char *, struct sshbuf *,
struct include_list *includes, struct connection_info *, int);
void parse_server_match_config(ServerOptions *,
struct include_list *includes, struct connection_info *);
int parse_server_match_testspec(struct connection_info *, char *);
int server_match_spec_complete(struct connection_info *);
void servconf_merge_subsystems(ServerOptions *, ServerOptions *);
void copy_set_server_options(ServerOptions *, ServerOptions *, int);
void dump_config(ServerOptions *);
char *derelativise_path(const char *);
void servconf_add_hostkey(const char *, const int,
ServerOptions *, const char *path, int);
void servconf_add_hostcert(
|