crypto/openssh/servconf.h

   1 /* $OpenBSD: servconf.h,v 1.157 2022/09/17 10:34:29 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 #define MAX_SUBSYSTEMS          256     /* Max # subsystems. */
  24
  25 /* permit_root_login */
  26 #define PERMIT_NOT_SET          -1
  27 #define PERMIT_NO               0
  28 #define PERMIT_FORCED_ONLY      1
  29 #define PERMIT_NO_PASSWD        2
  30 #define PERMIT_YES              3
  31
  32 /* use_privsep */
  33 #define PRIVSEP_OFF             0
  34 #define PRIVSEP_ON              1
  35 #define PRIVSEP_NOSANDBOX       2
  36
  37 /* PermitOpen */
  38 #define PERMITOPEN_ANY          0
  39 #define PERMITOPEN_NONE         -2
  40
  41 /* IgnoreRhosts */
  42 #define IGNORE_RHOSTS_NO        0
  43 #define IGNORE_RHOSTS_YES       1
  44 #define IGNORE_RHOSTS_SHOSTS    2
  45
  46 #define DEFAULT_AUTH_FAIL_MAX   6       /* Default for MaxAuthTries */
  47 #define DEFAULT_SESSIONS_MAX    10      /* Default for MaxSessions */
  48
  49 /* Magic name for internal sftp-server */
  50 #define INTERNAL_SFTP_NAME      "internal-sftp"
  51
  52 /* PubkeyAuthOptions flags */
  53 #define PUBKEYAUTH_TOUCH_REQUIRED       (1)
  54 #define PUBKEYAUTH_VERIFY_REQUIRED      (1<<1)
  55
  56 struct ssh;
  57 struct fwd_perm_list;
  58
  59 /*
  60  * Used to store addresses from ListenAddr directives. These may be
  61  * incomplete, as they may specify addresses that need to be merged
  62  * with any ports requested by ListenPort.
  63  */
  64 struct queued_listenaddr {
  65         char *addr;
  66         int port; /* <=0 if unspecified */
  67         char *rdomain;
  68 };
  69
  70 /* Resolved listen addresses, grouped by optional routing domain */
  71 struct listenaddr {
  72         char *rdomain;
  73         struct addrinfo *addrs;
  74 };
  75
  76 typedef struct {
  77         u_int   num_ports;
  78         u_int   ports_from_cmdline;
  79         int     ports[MAX_PORTS];       /* Port number to listen on. */
  80         struct queued_listenaddr *queued_listen_addrs;
  81         u_int   num_queued_listens;
  82         struct listenaddr *listen_addrs;
  83         u_int   num_listen_addrs;
  84         int     address_family;         /* Address family used by the server. */
  85
  86         char    *routing_domain;        /* Bind session to routing domain */
  87
  88         char   **host_key_files;        /* Files containing host keys. */
  89         int     *host_key_file_userprovided; /* Key was specified by user. */
  90         u_int   num_host_key_files;     /* Number of files for host keys. */
  91         char   **host_cert_files;       /* Files containing host certs. */
  92         u_int   num_host_cert_files;    /* Number of files for host certs. */
  93
  94         char   *host_key_agent;         /* ssh-agent socket for host keys. */
  95         char   *pid_file;               /* Where to put our pid */
  96         char   *moduli_file;            /* moduli file for DH-GEX */
  97         int     login_grace_time;       /* Disconnect if no auth in this time
  98                                          * (sec). */
  99         int     permit_root_login;      /* PERMIT_*, see above */
 100         int     ignore_rhosts;  /* Ignore .rhosts and .shosts. */
 101         int     ignore_user_known_hosts;        /* Ignore ~/.ssh/known_hosts
 102                                                  * for RhostsRsaAuth */
 103         int     print_motd;     /* If true, print /etc/motd. */
 104         int     print_lastlog;  /* If true, print lastlog */
 105         int     x11_forwarding; /* If true, permit inet (spoofing) X11 fwd. */
 106         int     x11_display_offset;     /* What DISPLAY number to start
 107                                          * searching at */
 108         int     x11_use_localhost;      /* If true, use localhost for fake X11 server. */
 109         char   *xauth_location; /* Location of xauth program */
 110         int     permit_tty;     /* If false, deny pty allocation */
 111         int     permit_user_rc; /* If false, deny ~/.ssh/rc execution */
 112         int     strict_modes;   /* If true, require string home dir modes. */
 113         int     tcp_keep_alive; /* If true, set SO_KEEPALIVE. */
 114         int     ip_qos_interactive;     /* IP ToS/DSCP/class for interactive */
 115         int     ip_qos_bulk;            /* IP ToS/DSCP/class for bulk traffic */
 116         char   *ciphers;        /* Supported SSH2 ciphers. */
 117         char   *macs;           /* Supported SSH2 macs. */
 118         char   *kex_algorithms; /* SSH2 kex methods in order of preference. */
 119         struct ForwardOptions fwd_opts; /* forwarding options */
 120         SyslogFacility log_facility;    /* Facility for system logging. */
 121         LogLevel log_level;     /* Level for system logging. */
 122         u_int   num_log_verbose;        /* Verbose log overrides */
 123         char    **log_verbose;
 124         int     hostbased_authentication;       /* If true, permit ssh2 hostbased auth */
 125         int     hostbased_uses_name_from_packet_only; /* experimental */
 126         char   *hostbased_accepted_algos; /* Algos allowed for hostbased */
 127         char   *hostkeyalgorithms;      /* SSH2 server key types */
 128         char   *ca_sign_algorithms;     /* Allowed CA signature algorithms */
 129         int     pubkey_authentication;  /* If true, permit ssh2 pubkey authentication. */
 130         char   *pubkey_accepted_algos;  /* Signature algos allowed for pubkey */
 131         int     pubkey_auth_options;    /* -1 or mask of PUBKEYAUTH_* flags */
 132         int     kerberos_authentication;        /* If true, permit Kerberos
 133                                                  * authentication. */
 134         int     kerberos_or_local_passwd;       /* If true, permit kerberos
 135                                                  * and any other password
 136                                                  * authentication mechanism,
 137                                                  * such as SecurID or
 138                                                  * /etc/passwd */
 139         int     kerberos_ticket_cleanup;        /* If true, destroy ticket
 140                                                  * file on logout. */
 141         int     kerberos_get_afs_token;         /* If true, try to get AFS token if
 142                                                  * authenticated with Kerberos. */
 143         int     gss_authentication;     /* If true, permit GSSAPI authentication */
 144         int     gss_cleanup_creds;      /* If true, destroy cred cache on logout */
 145         int     gss_strict_acceptor;    /* If true, restrict the GSSAPI acceptor name */
 146         int     password_authentication;        /* If true, permit password
 147                                                  * authentication. */
 148         int     kbd_interactive_authentication; /* If true, permit */
 149         int     permit_empty_passwd;    /* If false, do not permit empty
 150                                          * passwords. */
 151         int     permit_user_env;        /* If true, read ~/.ssh/environment */
 152         char   *permit_user_env_allowlist; /* pattern-list of allowed env names */
 153         int     compression;    /* If true, compression is allowed */
 154         int     allow_tcp_forwarding; /* One of FORWARD_* */
 155         int     allow_streamlocal_forwarding; /* One of FORWARD_* */
 156         int     allow_agent_forwarding;
 157         int     disable_forwarding;
 158         u_int num_allow_users;
 159         char   **allow_users;
 160         u_int num_deny_users;
 161         char   **deny_users;
 162         u_int num_allow_groups;
 163         char   **allow_groups;
 164         u_int num_deny_groups;
 165         char   **deny_groups;
 166
 167         u_int num_subsystems;
 168         char   *subsystem_name[MAX_SUBSYSTEMS];
 169         char   *subsystem_command[MAX_SUBSYSTEMS];
 170         char   *subsystem_args[MAX_SUBSYSTEMS];
 171
 172         u_int num_accept_env;
 173         char   **accept_env;
 174         u_int num_setenv;
 175         char   **setenv;
 176
 177         int     max_startups_begin;
 178         int     max_startups_rate;
 179         int     max_startups;
 180         int     per_source_max_startups;
 181         int     per_source_masklen_ipv4;
 182         int     per_source_masklen_ipv6;
 183         int     max_authtries;
 184         int     max_sessions;
 185         char   *banner;                 /* SSH-2 banner message */
 186         int     use_dns;
 187         int     client_alive_interval;  /*
 188                                          * poke the client this often to
 189                                          * see if it's still there
 190                                          */
 191         int     client_alive_count_max; /*
 192                                          * If the client is unresponsive
 193                                          * for this many intervals above,
 194                                          * disconnect the session
 195                                          */
 196
 197         u_int   num_authkeys_files;     /* Files containing public keys */
 198         char   **authorized_keys_files;
 199
 200         char   *adm_forced_command;
 201
 202         int     use_pam;                /* Enable auth via PAM */
 203
 204         int     permit_tun;
 205
 206         char   **permitted_opens;       /* May also be one of PERMITOPEN_* */
 207         u_int   num_permitted_opens;
 208         char   **permitted_listens; /* May also be one of PERMITOPEN_* */
 209         u_int   num_permitted_listens;
 210
 211         char   *chroot_directory;
 212         char   *revoked_keys_file;
 213         char   *trusted_user_ca_keys;
 214         char   *authorized_keys_command;
 215         char   *authorized_keys_command_user;
 216         char   *authorized_principals_file;
 217         char   *authorized_principals_command;
 218         char   *authorized_principals_command_user;
 219
 220         int64_t rekey_limit;
 221         int     rekey_interval;
 222
 223         char   *version_addendum;       /* Appended to SSH banner */
 224
 225         u_int   num_auth_methods;
 226         char   **auth_methods;
 227
 228         int     fingerprint_hash;
 229         int     expose_userauth_info;
 230         u_int64_t timing_secret;
 231         char   *sk_provider;
 232         int     required_rsa_size;      /* minimum size of RSA keys */
 233 }       ServerOptions;
 234
 235 /* Information about the incoming connection as used by Match */
 236 struct connection_info {
 237         const char *user;
 238         const char *host;       /* possibly resolved hostname */
 239         const char *address;    /* remote address */
 240         const char *laddress;   /* local address */
 241         int lport;              /* local port */
 242         const char *rdomain;    /* routing domain if available */
 243         int test;               /* test mode, allow some attributes to be
 244                                  * unspecified */
 245 };
 246
 247 /* List of included files for re-exec from the parsed configuration */
 248 struct include_item {
 249         char *selector;
 250         char *filename;
 251         struct sshbuf *contents;
 252         TAILQ_ENTRY(include_item) entry;
 253 };
 254 TAILQ_HEAD(include_list, include_item);
 255
 256
 257 /*
 258  * These are string config options that must be copied between the
 259  * Match sub-config and the main config, and must be sent from the
 260  * privsep child to the privsep master. We use a macro to ensure all
 261  * the options are copied and the copies are done in the correct order.
 262  *
 263  * NB. an option must appear in servconf.c:copy_set_server_options() or
 264  * COPY_MATCH_STRING_OPTS here but never both.
 265  */
 266 #define COPY_MATCH_STRING_OPTS() do { \
 267                 M_CP_STROPT(banner); \
 268                 M_CP_STROPT(trusted_user_ca_keys); \
 269                 M_CP_STROPT(revoked_keys_file); \
 270                 M_CP_STROPT(authorized_keys_command); \
 271                 M_CP_STROPT(authorized_keys_command_user); \
 272                 M_CP_STROPT(authorized_principals_file); \
 273                 M_CP_STROPT(authorized_principals_command); \
 274                 M_CP_STROPT(authorized_principals_command_user); \
 275                 M_CP_STROPT(hostbased_accepted_algos); \
 276                 M_CP_STROPT(pubkey_accepted_algos); \
 277                 M_CP_STROPT(ca_sign_algorithms); \
 278                 M_CP_STROPT(routing_domain); \
 279                 M_CP_STROPT(permit_user_env_allowlist); \
 280                 M_CP_STRARRAYOPT(authorized_keys_files, num_authkeys_files); \
 281                 M_CP_STRARRAYOPT(allow_users, num_allow_users); \
 282                 M_CP_STRARRAYOPT(deny_users, num_deny_users); \
 283                 M_CP_STRARRAYOPT(allow_groups, num_allow_groups); \
 284                 M_CP_STRARRAYOPT(deny_groups, num_deny_groups); \
 285                 M_CP_STRARRAYOPT(accept_env, num_accept_env); \
 286                 M_CP_STRARRAYOPT(setenv, num_setenv); \
 287                 M_CP_STRARRAYOPT(auth_methods, num_auth_methods); \
 288                 M_CP_STRARRAYOPT(permitted_opens, num_permitted_opens); \
 289                 M_CP_STRARRAYOPT(permitted_listens, num_permitted_listens); \
 290                 M_CP_STRARRAYOPT(log_verbose, num_log_verbose); \
 291         } while (0)
 292
 293 struct connection_info *get_connection_info(struct ssh *, int, int);
 294 void     initialize_server_options(ServerOptions *);
 295 void     fill_default_server_options(ServerOptions *);
 296 int      process_server_config_line(ServerOptions *, char *, const char *, int,
 297             int *, struct connection_info *, struct include_list *includes);
 298 void     process_permitopen(struct ssh *ssh, ServerOptions *options);
 299 void     load_server_config(const char *, struct sshbuf *);
 300 void     parse_server_config(ServerOptions *, const char *, struct sshbuf *,
 301             struct include_list *includes, struct connection_info *, int);
 302 void     parse_server_match_config(ServerOptions *,
 303             struct include_list *includes, struct connection_info *);
 304 int      parse_server_match_testspec(struct connection_info *, char *);
 305 int      server_match_spec_complete(struct connection_info *);
 306 void     copy_set_server_options(ServerOptions *, ServerOptions *, int);
 307 void     dump_config(ServerOptions *);
 308 char    *derelativise_path(const char *);
 309 void     servconf_add_hostkey(const char *, const int,
 310             ServerOptions *, const char *path, int);
 311 void     servconf_add_hostcert(const char *, const int,
 312             ServerOptions *, const char *path);
 313
 314 #endif                          /* SERVCONF_H */