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1/* $OpenBSD: readconf.h,v 1.162 2026/02/11 22:57:55 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 * Functions for reading the configuration file.
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 READCONF_H
17#define READCONF_H
18
19/* Data structure for representing option data. */
20
21#define SSH_MAX_HOSTS_FILES 32
22#define PATH_MAX_SUN (sizeof((struct sockaddr_un *)0)->sun_path)
23
24struct allowed_cname {
25 char *source_list;
26 char *target_list;
27};
28
29typedef struct {
30 char *host_arg; /* Host arg as specified on command line. */
31 int forward_agent; /* Forward authentication agent. */
32 char *forward_agent_sock_path; /* Optional path of the agent. */
33 int forward_x11; /* Forward X11 display. */
34 int forward_x11_timeout; /* Expiration for Cookies */
35 int forward_x11_trusted; /* Trust Forward X11 display. */
36 int exit_on_forward_failure; /* Exit if bind(2) fails for -L/-R */
37 char *xauth_location; /* Location for xauth program */
38 struct ForwardOptions fwd_opts; /* forwarding options */
39 int pubkey_authentication; /* Try ssh2 pubkey authentication. */
40 int hostbased_authentication; /* ssh2's rhosts_rsa */
41 int gss_authentication; /* Try GSS authentication */
42 int gss_deleg_creds; /* Delegate GSS credentials */
43 int password_authentication; /* Try password
44 * authentication. */
45 int kbd_interactive_authentication; /* Try keyboard-interactive auth. */
46 char *kbd_interactive_devices; /* Keyboard-interactive auth devices. */
47 int batch_mode; /* Batch mode: do not ask for passwords. */
48 int check_host_ip; /* Also keep track of keys for IP address */
49 int strict_host_key_checking; /* Strict host key checking. */
50 int compression; /* Compress packets in both directions. */
51 int tcp_keep_alive; /* Set SO_KEEPALIVE. */
52 int ip_qos_interactive; /* DSCP value for interactive */
53 int ip_qos_bulk; /* DSCP value for bulk traffic */
54 SyslogFacility log_facility; /* Facility for system logging. */
55 LogLevel log_level; /* Level for logging. */
56 u_int num_log_verbose; /* Verbose log overrides */
57 char **log_verbose;
58 int port; /* Port to connect. */
59 int address_family;
60 int connection_attempts; /* Max attempts (seconds) before
61 * giving up */
62 int connection_timeout; /* Max time (seconds) before
63 * aborting connection attempt */
64 int number_of_password_prompts; /* Max number of password
65 * prompts. */
66 char *ciphers; /* SSH2 ciphers in order of preference. */
67 char *macs; /* SSH2 macs in order of preference. */
68 char *hostkeyalgorithms; /* SSH2 server key types in order of preference. */
69 char *kex_algorithms; /* SSH2 kex methods in order of preference. */
70 int kex_algorithms_set; /* KexAlgorithms was set by the user */
71 char *ca_sign_algorithms; /* Allowed CA signature algorithms */
72 char *hostname; /* Real host to connect. */
73 char *tag; /* Configuration tag name. */
74 char *host_key_alias; /* hostname alias for .ssh/known_hosts */
75 char *proxy_command; /* Proxy command for connecting the host. */
76 char *user; /* User to log in as. */
77 int escape_char; /* Escape character; -2 = none */
78
79 u_int num_system_hostfiles; /* Paths for /etc/ssh/ssh_known_hosts */
80 char *system_hostfiles[SSH_MAX_HOSTS_FILES];
81 u_int num_user_hostfiles; /* Path for $HOME/.ssh/known_hosts */
82 char *user_hostfiles[SSH_MAX_HOSTS_FILES];
83 char *preferred_authentications;
84 char *bind_address; /* local socket address for connection to sshd */
85 char *bind_interface; /* local interface for bind address */
86 char *pkcs11_provider; /* PKCS#11 provider */
87 char *sk_provider; /* Security key provider */
88 int verify_host_key_dns; /* Verify host key using DNS */
89
90 int num_identity_files; /* Number of files for identities. */
91 char *identity_files[SSH_MAX_IDENTITY_FILES];
92 int identity_file_userprovided[SSH_MAX_IDENTITY_FILES];
93 struct sshkey *identity_keys[SSH_MAX_IDENTITY_FILES];
94
95 int num_certificate_files; /* Number of extra certificates for ssh. */
96 char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
97 int certificate_file_userprovided[SSH_MAX_CERTIFICATE_FILES];
98 struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
99
100 int add_keys_to_agent;
101 int add_keys_to_agent_lifespan;
102 char *identity_agent; /* Optional path to ssh-agent socket */
103
104 /* Local TCP/IP forward requests. */
105 int num_local_forwards;
106 struct Forward *local_forwards;
107
108 /* Remote TCP/IP forward requests. */
109 int num_remote_forwards;
110 struct Forward *remote_forwards;
111 int clear_forwardings;
112
113 /* Restrict remote dynamic forwarding */
114 char **permitted_remote_opens;
115 u_int num_permitted_remote_opens;
116
117 /* stdio forwarding (-W) host and port */
118 char *stdio_forward_host;
119 int stdio_forward_port;
120
121 int enable_ssh_keysign;
122 int64_t rekey_limit;
123 int rekey_interval;
124 int no_host_authentication_for_localhost;
125 int identities_only;
126 int server_alive_interval;
127 int server_alive_count_max;
128
129 u_int num_send_env;
130 char **send_env;
131 u_int num_setenv;
132 char **setenv;
133
134 char *control_path;
135 int control_master;
136 int control_persist; /* ControlPersist flag */
137 int control_persist_timeout; /* ControlPersist timeout (seconds) */
138
139 int hash_known_hosts;
140
141 int tun_open; /* tun(4) */
142 int tun_local; /* force tun device (optional) */
143 int tun_remote; /* force tun device (optional) */
144
145 char *local_command;
146 int permit_local_command;
147 char *remote_command;
148 int visual_host_key;
149
150 int request_tty;
151 int session_type;
152 int stdin_null;
153 int fork_after_authentication;
154
155 int proxy_use_fdpass;
156
157 int num_canonical_domains;
158 char **canonical_domains;
159 int canonicalize_hostname;
160 int canonicalize_max_dots;
161 int canonicalize_fallback_local;
162 int num_permitted_cnames;
163 struct allowed_cname *permitted_cnames;
164
165 u_int num_revoked_host_keys;
166 char **revoked_host_keys;
167
168 int fingerprint_hash;
169
170 int update_hostkeys; /* one of SSH_UPDATE_HOSTKEYS_* */
171
172 char *hostbased_accepted_algos;
173 char *pubkey_accepted_algos;
174
175 char *jump_user;
176 char *jump_host;
177 int jump_port;
178 char *jump_extra;
179
180 char *known_hosts_command;
181
182 int required_rsa_size; /* minimum size of RSA keys */
183 int enable_escape_commandline; /* ~C commandline */
184 int obscure_keystroke_timing_interval;
185 int warn_weak_crypto;
186
187 char **channel_timeouts; /* inactivity timeout by channel type */
188 u_int num_channel_timeouts;
189
190 char *version_addendum;
191
192 char *ignored_unknown; /* Pattern list of unknown tokens to ignore */
193} Options;
194
195#define SSH_PUBKEY_AUTH_NO 0x00
196#define SSH_PUBKEY_AUTH_UNBOUND 0x01
197#define SSH_PUBKEY_AUTH_HBOUND 0x02
198#define SSH_PUBKEY_AUTH_ALL 0x03
199
200#define SSH_CANONICALISE_NO 0
201#define SSH_CANONICALISE_YES 1
202#define SSH_CANONICALISE_ALWAYS 2
203
204#define SSHCTL_MASTER_NO 0
205#define SSHCTL_MASTER_YES 1
206#define SSHCTL_MASTER_AUTO 2
207#define SSHCTL_MASTER_ASK 3
208#define SSHCTL_MASTER_AUTO_ASK 4
209
210#define REQUEST_TTY_AUTO 0
211#define REQUEST_TTY_NO 1
212#define REQUEST_TTY_YES 2
213#define REQUEST_TTY_FORCE 3
214
215#define SESSION_TYPE_NONE 0
216#define SESSION_TYPE_SUBSYSTEM 1
217#define SESSION_TYPE_DEFAULT 2
218
219#define SSHCONF_CHECKPERM 1 /* check permissions on config file */
220#define SSHCONF_USERCONF 2 /* user provided config file not system */
221#define SSHCONF_FINAL 4 /* Final pass over config, after canon. */
222#define SSHCONF_NEVERMATCH 8 /* Match/Host never matches; internal only */
223
224#define SSH_UPDATE_HOSTKEYS_NO 0
225#define SSH_UPDATE_HOSTKEYS_YES 1
226#define SSH_UPDATE_HOSTKEYS_ASK 2
227
228#define SSH_STRICT_HOSTKEY_OFF 0
229#define SSH_STRICT_HOSTKEY_NEW 1
230#define SSH_STRICT_HOSTKEY_YES 2
231#define SSH_STRICT_HOSTKEY_ASK 3
232
233/* ObscureKeystrokes parameters */
234#define SSH_KEYSTROKE_DEFAULT_INTERVAL_MS 20
235#define SSH_KEYSTROKE_CHAFF_MIN_MS 1024
236#define SSH_KEYSTROKE_CHAFF_RNG_MS 2048
237
238const char *kex_default_pk_alg(void);
239char *ssh_connection_hash(const char *thishost, const char *host,
240 const char *portstr, const char *user, const char *jump_host);
241void initialize_options(Options *);
242int fill_default_options(Options *);
243void fill_default_options_for_canonicalization(Options *);
244void free_options(Options *o);
245int process_config_line(Options *, struct passwd *, const char *,
246 const char *, const char *, char *, const char *, int, int *, int);
247int read_config_file(const char *, struct passwd *, const char *,
248 const char *, const char *, Options *, int, int *);
249int parse_forward(struct Forward *, const char *, int, int);
250int parse_jump(const char *, Options *, int);
251int parse_ssh_uri(const char *, char **, char **, int *);
252int default_ssh_port(void);
253int option_clear_or_none(const char *);
254int config_has_permitted_cnames(Options *);
255void dump_client_config(Options *o, const char *host);
256
257void add_local_forward(Options *, const struct Forward *);
258void add_remote_forward(Options *, const struct Forward *);
259void add_identity_file(Options *, const char *, const char *, int);
260void add_certificate_file(Options *, const char *, int);
261
262#endif /* READCONF_H */