/* $OpenBSD: servconf.h,v 1.168 2024/09/15 01:18:26 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

/* 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;

/*
 * 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;
};

#define PER_SOURCE_PENALTY_OVERFLOW_DENY_ALL    1
#define PER_SOURCE_PENALTY_OVERFLOW_PERMISSIVE  2
struct per_source_penalty {
        int     enabled;
        int     max_sources4;
        int     max_sources6;
        int     overflow_mode;
        int     overflow_mode6;
        int     penalty_crash;
        int     penalty_grace;
        int     penalty_authfail;
        int     penalty_noauth;
        int     penalty_refuseconnection;
        int     penalty_max;
        int     penalty_min;
};

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;
        char    *per_source_penalty_exempt;
        struct per_source_penalty per_source_penalty;
        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 */
        char   *pam_service_name;

        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;

        char   *sshd_session_path;
        char   *sshd_auth_path;

        int     refuse_connection;

        int     use_blocklist;
}       ServerOptions;

/* Information about the incoming connection as used by Match */
struct connection_info {
        const char *user;
        int user_invalid;
        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_STROPT(pam_service_name); \
                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)

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     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 *);
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(const char *, const int,
            ServerOptions *, const char *path);

#endif                          /* SERVCONF_H */