auth-passwd.c revision 98684 
1/*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 *                    All rights reserved
5 * Password authentication.  This file contains the functions to check whether
6 * the password is valid for the user.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose.  Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
14 * Copyright (c) 1999 Dug Song.  All rights reserved.
15 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 *    notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 *    notice, this list of conditions and the following disclaimer in the
24 *    documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37
38#include "includes.h"
39RCSID("$OpenBSD: auth-passwd.c,v 1.27 2002/05/24 16:45:16 stevesk Exp $");
40RCSID("$FreeBSD: head/crypto/openssh/auth-passwd.c 98684 2002-06-23 16:09:08Z des $");
41
42#include "packet.h"
43#include "log.h"
44#include "servconf.h"
45#include "auth.h"
46
47
48extern ServerOptions options;
49
50/*
51 * Tries to authenticate the user using password.  Returns true if
52 * authentication succeeds.
53 */
54int
55auth_password(Authctxt *authctxt, const char *password)
56{
57	struct passwd * pw = authctxt->pw;
58
59	/* deny if no user. */
60	if (pw == NULL)
61		return 0;
62	if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
63		return 0;
64	if (*password == '\0' && options.permit_empty_passwd == 0)
65		return 0;
66#ifdef KRB5
67	if (options.kerberos_authentication == 1) {
68		int ret = auth_krb5_password(authctxt, password);
69		if (ret == 1 || ret == 0)
70			return ret;
71		/* Fall back to ordinary passwd authentication. */
72	}
73#endif
74#ifdef KRB4
75	if (options.kerberos_authentication == 1) {
76		int ret = auth_krb4_password(authctxt, password);
77		if (ret == 1 || ret == 0)
78			return ret;
79		/* Fall back to ordinary passwd authentication. */
80	}
81#endif
82#ifdef BSD_AUTH
83	if (auth_userokay(pw->pw_name, authctxt->style, "auth-ssh",
84	    (char *)password) == 0)
85		return 0;
86	else
87		return 1;
88#else
89	/* Check for users with no password. */
90	if (strcmp(password, "") == 0 && strcmp(pw->pw_passwd, "") == 0)
91		return 1;
92	else {
93		/* Encrypt the candidate password using the proper salt. */
94		char *encrypted_password = crypt(password,
95		    (pw->pw_passwd[0] && pw->pw_passwd[1]) ?
96		    pw->pw_passwd : "xx");
97		/*
98		 * Authentication is accepted if the encrypted passwords
99		 * are identical.
100		 */
101		return (strcmp(encrypted_password, pw->pw_passwd) == 0);
102	}
103#endif
104}
105