summaryrefslogtreecommitdiffstats
path: root/auth.h
blob: becc672b53f25416ee3ebb0f49b3c9bca7bf0a7d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/* $OpenBSD: auth.h,v 1.100 2019/09/06 05:23:55 djm 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>

#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 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 {
	char	*name;
	int	(*userauth)(struct ssh *);
	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(struct ssh *, const char *);

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

FILE	*auth_openkeyfile(const char *, struct passwd *, int);
FILE	*auth_openprincipals(const char *, struct passwd *, int);
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 */
const struct sshauthopt *auth_options(struct ssh *);
int	 auth_activate_options(struct ssh *, struct sshauthopt *);
void	 auth_restrict_session(struct ssh *);
int	 auth_authorise_keyopts(struct ssh *, struct passwd *pw,
    struct sshauthopt *, int, const char *);
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);

#define	SSH_SUBPROCESS_STDOUT_DISCARD  (1)     /* Discard stdout */
#define	SSH_SUBPROCESS_STDOUT_CAPTURE  (1<<1)  /* Redirect stdout */
#define	SSH_SUBPROCESS_STDERR_DISCARD  (1<<2)  /* Discard stderr */
pid_t	subprocess(const char *, struct passwd *,
    const char *, int, char **, FILE **, u_int flags);

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 */