/* $OpenBSD: auth.h,v 1.108 2024/05/17 06:42:04 jsg Exp $ */

/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef AUTH_H
#define AUTH_H

#include <signal.h>
#include <stdio.h>

#ifdef HAVE_LOGIN_CAP
#include <login_cap.h>
#endif
#ifdef BSD_AUTH
#include <bsd_auth.h>
#endif
#ifdef KRB5
#include <krb5.h>
#endif

struct passwd;
struct ssh;
struct sshbuf;
struct sshkey;
struct sshkey_cert;
struct sshauthopt;

typedef struct Authctxt Authctxt;
typedef struct Authmethod Authmethod;
typedef struct KbdintDevice KbdintDevice;

struct Authctxt {
        sig_atomic_t     success;
        int              authenticated; /* authenticated and alarms cancelled */
        int              postponed;     /* authentication needs another step */
        int              valid;         /* user exists and is allowed to login */
        int              attempt;
        int              failures;
        int              server_caused_failure;
        int              force_pwchange;
        char            *user;          /* username sent by the client */
        char            *service;
        struct passwd   *pw;            /* set if 'valid' */
        char            *style;

        /* Method lists for multiple authentication */
        char            **auth_methods; /* modified from server config */
        u_int            num_auth_methods;

        /* Authentication method-specific data */
        void            *methoddata;
        void            *kbdintctxt;
#ifdef BSD_AUTH
        auth_session_t  *as;
#endif
#ifdef KRB5
        krb5_context     krb5_ctx;
        krb5_ccache      krb5_fwd_ccache;
        krb5_principal   krb5_user;
        char            *krb5_ticket_file;
        char            *krb5_ccname;
#endif
        struct sshbuf   *loginmsg;

        /* Authentication keys already used; these will be refused henceforth */
        struct sshkey   **prev_keys;
        u_int            nprev_keys;

        /* Last used key and ancillary information from active auth method */
        struct sshkey   *auth_method_key;
        char            *auth_method_info;

        /* Information exposed to session */
        struct sshbuf   *session_info;  /* Auth info for environment */
};

/*
 * Every authentication method has to handle authentication requests for
 * non-existing users, or for users that are not allowed to login. In this
 * case 'valid' is set to 0, but 'user' points to the username requested by
 * the client.
 */

struct authmethod_cfg {
        const char *name;
        const char *synonym;
        int *enabled;
};

struct Authmethod {
        struct authmethod_cfg *cfg;
        int     (*userauth)(struct ssh *, const char *);
};

/*
 * Keyboard interactive device:
 * init_ctx     returns: non NULL upon success
 * query        returns: 0 - success, otherwise failure
 * respond      returns: 0 - success, 1 - need further interaction,
 *              otherwise - failure
 */
struct KbdintDevice
{
        const char *name;
        void*   (*init_ctx)(Authctxt*);
        int     (*query)(void *ctx, char **name, char **infotxt,
                    u_int *numprompts, char ***prompts, u_int **echo_on);
        int     (*respond)(void *ctx, u_int numresp, char **responses);
        void    (*free_ctx)(void *ctx);
};

int
auth_rhosts2(struct passwd *, const char *, const char *, const char *);

int      auth_password(struct ssh *, const char *);

int      hostbased_key_allowed(struct ssh *, struct passwd *,
            const char *, char *, struct sshkey *);
int      user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *,
    int, struct sshauthopt **);
int      auth2_key_already_used(Authctxt *, const struct sshkey *);

/*
 * Handling auth method-specific information for logging and prevention
 * of key reuse during multiple authentication.
 */
void     auth2_authctxt_reset_info(Authctxt *);
void     auth2_record_key(Authctxt *, int, const struct sshkey *);
void     auth2_record_info(Authctxt *authctxt, const char *, ...)
            __attribute__((__format__ (printf, 2, 3)))
            __attribute__((__nonnull__ (2)));
void     auth2_update_session_info(Authctxt *, const char *, const char *);

#ifdef KRB5
int     auth_krb5_password(Authctxt *authctxt, const char *password);
void    krb5_cleanup_proc(Authctxt *authctxt);
#endif /* KRB5 */

#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
#include <shadow.h>
int auth_shadow_acctexpired(struct spwd *);
int auth_shadow_pwexpired(Authctxt *);
#endif

#include "auth-pam.h"
#include "audit.h"
void remove_kbdint_device(const char *);

void    do_authentication2(struct ssh *);

void    auth_log(struct ssh *, int, int, const char *, const char *);
void    auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn));
void    userauth_finish(struct ssh *, int, const char *, const char *);
int     auth_root_allowed(struct ssh *, const char *);

char    *auth2_read_banner(void);
int      auth2_methods_valid(const char *, int);
int      auth2_update_methods_lists(Authctxt *, const char *, const char *);
int      auth2_setup_methods_lists(Authctxt *);
int      auth2_method_allowed(Authctxt *, const char *, const char *);

void    privsep_challenge_enable(void);

int     auth2_challenge(struct ssh *, char *);
void    auth2_challenge_stop(struct ssh *);
int     bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **);
int     bsdauth_respond(void *, u_int, char **);

int     allowed_user(struct ssh *, struct passwd *);
struct passwd * getpwnamallow(struct ssh *, const char *user);

char    *expand_authorized_keys(const char *, struct passwd *pw);
char    *authorized_principals_file(struct passwd *);

int      auth_key_is_revoked(struct sshkey *);

const char      *auth_get_canonical_hostname(struct ssh *, int);

HostStatus
check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *,
    const char *, const char *);

/* hostkey handling */
struct sshkey   *get_hostkey_by_index(int);
struct sshkey   *get_hostkey_public_by_index(int, struct ssh *);
struct sshkey   *get_hostkey_public_by_type(int, int, struct ssh *);
struct sshkey   *get_hostkey_private_by_type(int, int, struct ssh *);
int      get_hostkey_index(struct sshkey *, int, struct ssh *);
int      sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *,
    u_char **, size_t *, const u_char *, size_t, const char *);

/* Key / cert options linkage to auth layer */
int      auth_activate_options(struct ssh *, struct sshauthopt *);
void     auth_restrict_session(struct ssh *);
void     auth_log_authopts(const char *, const struct sshauthopt *, int);

/* debug messages during authentication */
void     auth_debug_add(const char *fmt,...)
    __attribute__((format(printf, 1, 2)));
void     auth_debug_send(struct ssh *);
void     auth_debug_reset(void);

struct passwd *fakepw(void);

/* auth2-pubkeyfile.c */
int      auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int,
    const char *, const char *, const char *);
int      auth_check_principals_line(char *, const struct sshkey_cert *,
    const char *, struct sshauthopt **);
int      auth_process_principals(FILE *, const char *,
    const struct sshkey_cert *, struct sshauthopt **);
int      auth_check_authkey_line(struct passwd *, struct sshkey *,
    char *, const char *, const char *, const char *, struct sshauthopt **);
int      auth_check_authkeys_file(struct passwd *, FILE *, char *,
    struct sshkey *, const char *, const char *, struct sshauthopt **);
FILE    *auth_openkeyfile(const char *, struct passwd *, int);
FILE    *auth_openprincipals(const char *, struct passwd *, int);

int      sys_auth_passwd(struct ssh *, const char *);

#if defined(KRB5) && !defined(HEIMDAL)
krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *);
#endif

#endif /* AUTH_H */