xref: /freebsd/crypto/openssh/auth.h (revision 9a0c3479e22feda1bdb2db4b97f9deb1b5fa6269)
1 /* $OpenBSD: auth.h,v 1.72 2012/12/02 20:34:09 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 
45 typedef struct Authctxt Authctxt;
46 typedef struct Authmethod Authmethod;
47 typedef struct KbdintDevice KbdintDevice;
48 
49 struct Authctxt {
50 	sig_atomic_t	 success;
51 	int		 authenticated;	/* authenticated and alarms cancelled */
52 	int		 postponed;	/* authentication needs another step */
53 	int		 valid;		/* user exists and is allowed to login */
54 	int		 attempt;
55 	int		 failures;
56 	int		 server_caused_failure;
57 	int		 force_pwchange;
58 	char		*user;		/* username sent by the client */
59 	char		*service;
60 	struct passwd	*pw;		/* set if 'valid' */
61 	char		*style;
62 	void		*kbdintctxt;
63 	void		*jpake_ctx;
64 #ifdef BSD_AUTH
65 	auth_session_t	*as;
66 #endif
67 	char		**auth_methods;	/* modified from server config */
68 	u_int		 num_auth_methods;
69 #ifdef KRB5
70 	krb5_context	 krb5_ctx;
71 	krb5_ccache	 krb5_fwd_ccache;
72 	krb5_principal	 krb5_user;
73 	char		*krb5_ticket_file;
74 	char		*krb5_ccname;
75 #endif
76 	Buffer		*loginmsg;
77 	void		*methoddata;
78 };
79 /*
80  * Every authentication method has to handle authentication requests for
81  * non-existing users, or for users that are not allowed to login. In this
82  * case 'valid' is set to 0, but 'user' points to the username requested by
83  * the client.
84  */
85 
86 struct Authmethod {
87 	char	*name;
88 	int	(*userauth)(Authctxt *authctxt);
89 	int	*enabled;
90 };
91 
92 /*
93  * Keyboard interactive device:
94  * init_ctx	returns: non NULL upon success
95  * query	returns: 0 - success, otherwise failure
96  * respond	returns: 0 - success, 1 - need further interaction,
97  *		otherwise - failure
98  */
99 struct KbdintDevice
100 {
101 	const char *name;
102 	void*	(*init_ctx)(Authctxt*);
103 	int	(*query)(void *ctx, char **name, char **infotxt,
104 		    u_int *numprompts, char ***prompts, u_int **echo_on);
105 	int	(*respond)(void *ctx, u_int numresp, char **responses);
106 	void	(*free_ctx)(void *ctx);
107 };
108 
109 int      auth_rhosts(struct passwd *, const char *);
110 int
111 auth_rhosts2(struct passwd *, const char *, const char *, const char *);
112 
113 int	 auth_rhosts_rsa(Authctxt *, char *, Key *);
114 int      auth_password(Authctxt *, const char *);
115 int      auth_rsa(Authctxt *, BIGNUM *);
116 int      auth_rsa_challenge_dialog(Key *);
117 BIGNUM	*auth_rsa_generate_challenge(Key *);
118 int	 auth_rsa_verify_response(Key *, BIGNUM *, u_char[]);
119 int	 auth_rsa_key_allowed(struct passwd *, BIGNUM *, Key **);
120 
121 int	 auth_rhosts_rsa_key_allowed(struct passwd *, char *, char *, Key *);
122 int	 hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
123 int	 user_key_allowed(struct passwd *, Key *);
124 
125 struct stat;
126 int	 auth_secure_path(const char *, struct stat *, const char *, uid_t,
127     char *, size_t);
128 
129 #ifdef KRB5
130 int	auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *);
131 int	auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt);
132 int	auth_krb5_password(Authctxt *authctxt, const char *password);
133 void	krb5_cleanup_proc(Authctxt *authctxt);
134 #endif /* KRB5 */
135 
136 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
137 #include <shadow.h>
138 int auth_shadow_acctexpired(struct spwd *);
139 int auth_shadow_pwexpired(Authctxt *);
140 #endif
141 
142 #include "auth-pam.h"
143 #include "audit.h"
144 void remove_kbdint_device(const char *);
145 
146 void disable_forwarding(void);
147 
148 void	do_authentication(Authctxt *);
149 void	do_authentication2(Authctxt *);
150 
151 void	auth_log(Authctxt *, int, int, const char *, const char *,
152     const char *);
153 void	userauth_finish(Authctxt *, int, const char *, const char *);
154 int	auth_root_allowed(const char *);
155 
156 void	userauth_send_banner(const char *);
157 
158 char	*auth2_read_banner(void);
159 int	 auth2_methods_valid(const char *, int);
160 int	 auth2_update_methods_lists(Authctxt *, const char *);
161 int	 auth2_setup_methods_lists(Authctxt *);
162 
163 void	privsep_challenge_enable(void);
164 
165 int	auth2_challenge(Authctxt *, char *);
166 void	auth2_challenge_stop(Authctxt *);
167 int	bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **);
168 int	bsdauth_respond(void *, u_int, char **);
169 int	skey_query(void *, char **, char **, u_int *, char ***, u_int **);
170 int	skey_respond(void *, u_int, char **);
171 
172 void	auth2_jpake_get_pwdata(Authctxt *, BIGNUM **, char **, char **);
173 void	auth2_jpake_stop(Authctxt *);
174 
175 int	allowed_user(struct passwd *);
176 struct passwd * getpwnamallow(const char *user);
177 
178 char	*get_challenge(Authctxt *);
179 int	verify_response(Authctxt *, const char *);
180 void	abandon_challenge_response(Authctxt *);
181 
182 char	*expand_authorized_keys(const char *, struct passwd *pw);
183 char	*authorized_principals_file(struct passwd *);
184 
185 FILE	*auth_openkeyfile(const char *, struct passwd *, int);
186 FILE	*auth_openprincipals(const char *, struct passwd *, int);
187 int	 auth_key_is_revoked(Key *);
188 
189 HostStatus
190 check_key_in_hostfiles(struct passwd *, Key *, const char *,
191     const char *, const char *);
192 
193 /* hostkey handling */
194 Key	*get_hostkey_by_index(int);
195 Key	*get_hostkey_public_by_type(int);
196 Key	*get_hostkey_private_by_type(int);
197 int	 get_hostkey_index(Key *);
198 int	 ssh1_session_key(BIGNUM *);
199 
200 /* debug messages during authentication */
201 void	 auth_debug_add(const char *fmt,...) __attribute__((format(printf, 1, 2)));
202 void	 auth_debug_send(void);
203 void	 auth_debug_reset(void);
204 
205 struct passwd *fakepw(void);
206 
207 int	 sys_auth_passwd(Authctxt *, const char *);
208 
209 #define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
210 
211 #define SKEY_PROMPT "\nS/Key Password: "
212 
213 #if defined(KRB5) && !defined(HEIMDAL)
214 #include <krb5.h>
215 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *);
216 #endif
217 #endif
218