1/* $OpenBSD: auth.h,v 1.96 2018/04/10 00:10:49 djm Exp $ */
2
3/*
4 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#ifndef AUTH_H
29#define AUTH_H
30
31#include <signal.h>
32
33#include <openssl/rsa.h>
34
35#ifdef HAVE_LOGIN_CAP
36#include <login_cap.h>
37#endif
38#ifdef BSD_AUTH
39#include <bsd_auth.h>
40#endif
41#ifdef KRB5
42#include <krb5.h>
43#endif
44
45struct passwd;
46struct ssh;
47struct sshbuf;
48struct sshkey;
49struct sshauthopt;
50
51typedef struct Authctxt Authctxt;
52typedef struct Authmethod Authmethod;
53typedef struct KbdintDevice KbdintDevice;
54
55struct Authctxt {
56	sig_atomic_t	 success;
57	int		 authenticated;	/* authenticated and alarms cancelled */
58	int		 postponed;	/* authentication needs another step */
59	int		 valid;		/* user exists and is allowed to login */
60	int		 attempt;
61	int		 failures;
62	int		 server_caused_failure;
63	int		 force_pwchange;
64	char		*user;		/* username sent by the client */
65	char		*service;
66	struct passwd	*pw;		/* set if 'valid' */
67	char		*style;
68
69	/* Method lists for multiple authentication */
70	char		**auth_methods;	/* modified from server config */
71	u_int		 num_auth_methods;
72
73	/* Authentication method-specific data */
74	void		*methoddata;
75	void		*kbdintctxt;
76#ifdef BSD_AUTH
77	auth_session_t	*as;
78#endif
79#ifdef KRB5
80	krb5_context	 krb5_ctx;
81	krb5_ccache	 krb5_fwd_ccache;
82	krb5_principal	 krb5_user;
83	char		*krb5_ticket_file;
84	char		*krb5_ccname;
85#endif
86	struct sshbuf	*loginmsg;
87
88	/* Authentication keys already used; these will be refused henceforth */
89	struct sshkey	**prev_keys;
90	u_int		 nprev_keys;
91
92	/* Last used key and ancillary information from active auth method */
93	struct sshkey	*auth_method_key;
94	char		*auth_method_info;
95
96	/* Information exposed to session */
97	struct sshbuf	*session_info;	/* Auth info for environment */
98};
99
100/*
101 * Every authentication method has to handle authentication requests for
102 * non-existing users, or for users that are not allowed to login. In this
103 * case 'valid' is set to 0, but 'user' points to the username requested by
104 * the client.
105 */
106
107struct Authmethod {
108	char	*name;
109	int	(*userauth)(struct ssh *);
110	int	*enabled;
111};
112
113/*
114 * Keyboard interactive device:
115 * init_ctx	returns: non NULL upon success
116 * query	returns: 0 - success, otherwise failure
117 * respond	returns: 0 - success, 1 - need further interaction,
118 *		otherwise - failure
119 */
120struct KbdintDevice
121{
122	const char *name;
123	void*	(*init_ctx)(Authctxt*);
124	int	(*query)(void *ctx, char **name, char **infotxt,
125		    u_int *numprompts, char ***prompts, u_int **echo_on);
126	int	(*respond)(void *ctx, u_int numresp, char **responses);
127	void	(*free_ctx)(void *ctx);
128};
129
130int
131auth_rhosts2(struct passwd *, const char *, const char *, const char *);
132
133int      auth_password(struct ssh *, const char *);
134
135int	 hostbased_key_allowed(struct passwd *, const char *, char *,
136	    struct sshkey *);
137int	 user_key_allowed(struct ssh *, struct passwd *, struct sshkey *, int,
138    struct sshauthopt **);
139int	 auth2_key_already_used(Authctxt *, const struct sshkey *);
140
141/*
142 * Handling auth method-specific information for logging and prevention
143 * of key reuse during multiple authentication.
144 */
145void	 auth2_authctxt_reset_info(Authctxt *);
146void	 auth2_record_key(Authctxt *, int, const struct sshkey *);
147void	 auth2_record_info(Authctxt *authctxt, const char *, ...)
148	    __attribute__((__format__ (printf, 2, 3)))
149	    __attribute__((__nonnull__ (2)));
150void	 auth2_update_session_info(Authctxt *, const char *, const char *);
151
152#ifdef KRB5
153int	auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *);
154int	auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt);
155int	auth_krb5_password(Authctxt *authctxt, const char *password);
156void	krb5_cleanup_proc(Authctxt *authctxt);
157#endif /* KRB5 */
158
159#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
160#include <shadow.h>
161int auth_shadow_acctexpired(struct spwd *);
162int auth_shadow_pwexpired(Authctxt *);
163#endif
164
165#include "auth-pam.h"
166#include "audit.h"
167void remove_kbdint_device(const char *);
168
169void	do_authentication2(Authctxt *);
170
171void	auth_log(Authctxt *, int, int, const char *, const char *);
172void	auth_maxtries_exceeded(Authctxt *) __attribute__((noreturn));
173void	userauth_finish(struct ssh *, int, const char *, const char *);
174int	auth_root_allowed(struct ssh *, const char *);
175
176void	userauth_send_banner(const char *);
177
178char	*auth2_read_banner(void);
179int	 auth2_methods_valid(const char *, int);
180int	 auth2_update_methods_lists(Authctxt *, const char *, const char *);
181int	 auth2_setup_methods_lists(Authctxt *);
182int	 auth2_method_allowed(Authctxt *, const char *, const char *);
183
184void	privsep_challenge_enable(void);
185
186int	auth2_challenge(struct ssh *, char *);
187void	auth2_challenge_stop(struct ssh *);
188int	bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **);
189int	bsdauth_respond(void *, u_int, char **);
190
191int	allowed_user(struct passwd *);
192struct passwd * getpwnamallow(const char *user);
193
194char	*expand_authorized_keys(const char *, struct passwd *pw);
195char	*authorized_principals_file(struct passwd *);
196
197FILE	*auth_openkeyfile(const char *, struct passwd *, int);
198FILE	*auth_openprincipals(const char *, struct passwd *, int);
199int	 auth_key_is_revoked(struct sshkey *);
200
201const char	*auth_get_canonical_hostname(struct ssh *, int);
202
203HostStatus
204check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *,
205    const char *, const char *);
206
207/* hostkey handling */
208struct sshkey	*get_hostkey_by_index(int);
209struct sshkey	*get_hostkey_public_by_index(int, struct ssh *);
210struct sshkey	*get_hostkey_public_by_type(int, int, struct ssh *);
211struct sshkey	*get_hostkey_private_by_type(int, int, struct ssh *);
212int	 get_hostkey_index(struct sshkey *, int, struct ssh *);
213int	 sshd_hostkey_sign(struct sshkey *, struct sshkey *, u_char **,
214	     size_t *, const u_char *, size_t, const char *, u_int);
215
216/* Key / cert options linkage to auth layer */
217const struct sshauthopt *auth_options(struct ssh *);
218int	 auth_activate_options(struct ssh *, struct sshauthopt *);
219void	 auth_restrict_session(struct ssh *);
220int	 auth_authorise_keyopts(struct ssh *, struct passwd *pw,
221    struct sshauthopt *, int, const char *);
222void	 auth_log_authopts(const char *, const struct sshauthopt *, int);
223
224/* debug messages during authentication */
225void	 auth_debug_add(const char *fmt,...)
226    __attribute__((format(printf, 1, 2)));
227void	 auth_debug_send(void);
228void	 auth_debug_reset(void);
229
230struct passwd *fakepw(void);
231
232#define	SSH_SUBPROCESS_STDOUT_DISCARD  (1)     /* Discard stdout */
233#define	SSH_SUBPROCESS_STDOUT_CAPTURE  (1<<1)  /* Redirect stdout */
234#define	SSH_SUBPROCESS_STDERR_DISCARD  (1<<2)  /* Discard stderr */
235pid_t	subprocess(const char *, struct passwd *,
236    const char *, int, char **, FILE **, u_int flags);
237
238int	 sys_auth_passwd(struct ssh *, const char *);
239
240#if defined(KRB5) && !defined(HEIMDAL)
241#include <krb5.h>
242krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *);
243#endif
244#endif
245