auth.h

/* $OpenBSD: auth.h,v 1.89 2016/08/13 17:47:41 markus 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 <openssl/rsa.h>

#ifdef HAVE_LOGIN_CAP
#include <login_cap.h>
#endif
#ifdef BSD_AUTH
#include <bsd_auth.h>
#endif
#ifdef KRB5
#include <krb5.h>
#endif
#ifdef AFS_KRB5
#include <krbafs.h>
#endif

struct ssh;
struct sshkey;

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;
    void        *kbdintctxt;
    char        *info;      /* Extra info for next auth_log */
#ifdef BSD_AUTH
    auth_session_t  *as;
#endif
    char        **auth_methods; /* modified from server config */
    u_int        num_auth_methods;
#ifdef KRB5
    krb5_context     krb5_ctx;
    krb5_ccache  krb5_fwd_ccache;
    krb5_principal   krb5_user;
    char        *krb5_ticket_file;
    char        *krb5_ccname;
#endif
#ifdef SESSION_HOOKS
    char        *session_env_file;
#endif
    Buffer      *loginmsg;
    void        *methoddata;

    struct sshkey   **prev_userkeys;
    u_int        nprev_userkeys;
};
/*
 * 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 {
    char    *name;
    int (*userauth)(Authctxt *authctxt);
    int *enabled;
};

/*
 * 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(Authctxt *, const char *);

int  hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
int  user_key_allowed(struct passwd *, Key *, int);
void     pubkey_auth_info(Authctxt *, const Key *, const char *, ...)
        __attribute__((__format__ (printf, 3, 4)));
void     auth2_record_userkey(Authctxt *, struct sshkey *);
int  auth2_userkey_already_used(Authctxt *, struct sshkey *);

struct stat;
int  auth_secure_path(const char *, struct stat *, const char *, uid_t,
    char *, size_t);

#ifdef KRB5
int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *);
int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt);
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 disable_forwarding(void);

void    do_authentication2(Authctxt *);

void    auth_info(Authctxt *authctxt, const char *, ...)
        __attribute__((__format__ (printf, 2, 3)))
        __attribute__((__nonnull__ (2)));
void    auth_log(Authctxt *, int, int, const char *, const char *);
void    auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn));
void    userauth_finish(Authctxt *, int, const char *, const char *);
int auth_root_allowed(const char *);

void    userauth_send_banner(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(Authctxt *, char *);
void    auth2_challenge_stop(Authctxt *);
int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **);
int bsdauth_respond(void *, u_int, char **);
int skey_query(void *, char **, char **, u_int *, char ***, u_int **);
int skey_respond(void *, u_int, char **);

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

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

FILE    *auth_openkeyfile(const char *, struct passwd *, int);
FILE    *auth_openprincipals(const char *, struct passwd *, int);
int  auth_key_is_revoked(Key *);

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

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

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

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

struct passwd *fakepw(void);

int  sys_auth_passwd(Authctxt *, const char *);

#define SKEY_PROMPT "\nS/Key Password: "

#if defined(KRB5) && !defined(HEIMDAL)
#include <krb5.h>
krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *);
#endif
#endif