xref: /freebsd/crypto/openssh/auth-passwd.c (revision 41466b50c1d5bfd1cf6adaae547a579a75d7c04e)
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"
39 RCSID("$OpenBSD: auth-passwd.c,v 1.22 2001/03/20 18:57:04 markus Exp $");
40 RCSID("$FreeBSD$");
41 
42 #include "packet.h"
43 #include "xmalloc.h"
44 #include "log.h"
45 #include "servconf.h"
46 #include "auth.h"
47 
48 
49 extern ServerOptions options;
50 
51 /*
52  * Tries to authenticate the user using password.  Returns true if
53  * authentication succeeds.
54  */
55 int
56 auth_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