auth-passwd.c revision 76262 
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 1.22 2001/03/20 18:57:04 markus Exp $");
40RCSID("$FreeBSD: head/crypto/openssh/auth-passwd.c 76262 2001-05-04 04:14:23Z green $");
41
42#include "packet.h"
43#include "xmalloc.h"
44#include "log.h"
45#include "servconf.h"
46#include "auth.h"
47
48
49extern ServerOptions options;
50
51/*
52 * Tries to authenticate the user using password.  Returns true if
53 * authentication succeeds.
54 */
55int
56auth_password(Authctxt *authctxt, const char *password)
57{
58	struct passwd * pw = authctxt->pw;
59	char *encrypted_password;
60
61	/* deny if no user. */
62	if (pw == NULL)
63		return 0;
64	if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
65		return 0;
66	if (*password == '\0' && options.permit_empty_passwd == 0)
67		return 0;
68#ifdef BSD_AUTH
69	if (auth_userokay(pw->pw_name, authctxt->style, "auth-ssh",
70	    (char *)password) == 0)
71		return 0;
72	else
73		return 1;
74#endif
75#ifdef KRB5
76	if (options.kerberos_authentication == 1) {
77	  	if (auth_krb5_password(pw, password))
78		  	return 1;
79		/* Fall back to ordinary passwd authentication. */
80	}
81
82#endif /* KRB5 */
83#ifdef KRB4
84	if (options.kerberos_authentication == 1) {
85		int ret = auth_krb4_password(pw, password);
86		if (ret == 1 || ret == 0)
87			return ret;
88		/* Fall back to ordinary passwd authentication. */
89	}
90#endif
91
92	/* Check for users with no password. */
93	if (strcmp(password, "") == 0 && strcmp(pw->pw_passwd, "") == 0)
94		return 1;
95	/* Encrypt the candidate password using the proper salt. */
96	encrypted_password = crypt(password,
97	    (pw->pw_passwd[0] && pw->pw_passwd[1]) ? pw->pw_passwd : "xx");
98
99	/* Authentication is accepted if the encrypted passwords are identical. */
100	return (strcmp(encrypted_password, pw->pw_passwd) == 0);
101}
102