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1 | /* $OpenBSD: auth-passwd.c,v 1.43 2007/09/21 08:15:29 djm Exp $ */ | |
2 | /* | |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * Password authentication. This file contains the functions to check whether | |
7 | * the password is valid for the user. | |
8 | * | |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
14 | * | |
15 | * Copyright (c) 1999 Dug Song. All rights reserved. | |
16 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
17 | * | |
18 | * Redistribution and use in source and binary forms, with or without | |
19 | * modification, are permitted provided that the following conditions | |
20 | * are met: | |
21 | * 1. Redistributions of source code must retain the above copyright | |
22 | * notice, this list of conditions and the following disclaimer. | |
23 | * 2. Redistributions in binary form must reproduce the above copyright | |
24 | * notice, this list of conditions and the following disclaimer in the | |
25 | * documentation and/or other materials provided with the distribution. | |
26 | * | |
27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
28 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
29 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
30 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
31 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
32 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
33 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
34 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
35 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
36 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
37 | */ | |
38 | ||
39 | #include "includes.h" | |
40 | ||
41 | #include <sys/types.h> | |
42 | ||
43 | #include <pwd.h> | |
44 | #include <stdio.h> | |
45 | #include <string.h> | |
46 | #include <stdarg.h> | |
47 | ||
48 | #include "packet.h" | |
49 | #include "buffer.h" | |
50 | #include "log.h" | |
51 | #include "servconf.h" | |
52 | #include "key.h" | |
53 | #include "hostfile.h" | |
54 | #include "auth.h" | |
55 | #include "auth-options.h" | |
56 | ||
57 | extern Buffer loginmsg; | |
58 | extern ServerOptions options; | |
59 | ||
60 | #ifdef HAVE_LOGIN_CAP | |
61 | extern login_cap_t *lc; | |
62 | #endif | |
63 | ||
64 | ||
65 | #define DAY (24L * 60 * 60) /* 1 day in seconds */ | |
66 | #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ | |
67 | ||
68 | void | |
69 | disable_forwarding(void) | |
70 | { | |
71 | no_port_forwarding_flag = 1; | |
72 | no_agent_forwarding_flag = 1; | |
73 | no_x11_forwarding_flag = 1; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Tries to authenticate the user using password. Returns true if | |
78 | * authentication succeeds. | |
79 | */ | |
80 | int | |
81 | auth_password(Authctxt *authctxt, const char *password) | |
82 | { | |
83 | struct passwd * pw = authctxt->pw; | |
84 | int result, ok = authctxt->valid; | |
85 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
86 | static int expire_checked = 0; | |
87 | #endif | |
88 | ||
89 | #ifndef HAVE_CYGWIN | |
90 | if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) | |
91 | ok = 0; | |
92 | #endif | |
93 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
94 | return 0; | |
95 | ||
96 | #ifdef KRB5 | |
97 | if (options.kerberos_authentication == 1) { | |
98 | int ret = auth_krb5_password(authctxt, password); | |
99 | if (ret == 1 || ret == 0) | |
100 | return ret && ok; | |
101 | /* Fall back to ordinary passwd authentication. */ | |
102 | } | |
103 | #endif | |
104 | #ifdef HAVE_CYGWIN | |
105 | { | |
106 | HANDLE hToken = cygwin_logon_user(pw, password); | |
107 | ||
108 | if (hToken == INVALID_HANDLE_VALUE) | |
109 | return 0; | |
110 | cygwin_set_impersonation_token(hToken); | |
111 | return ok; | |
112 | } | |
113 | #endif | |
114 | #ifdef USE_PAM | |
115 | if (options.use_pam) | |
116 | return (sshpam_auth_passwd(authctxt, password) && ok); | |
117 | #endif | |
118 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
119 | if (!expire_checked) { | |
120 | expire_checked = 1; | |
121 | if (auth_shadow_pwexpired(authctxt)) | |
122 | authctxt->force_pwchange = 1; | |
123 | } | |
124 | #endif | |
125 | result = sys_auth_passwd(authctxt, password); | |
126 | if (authctxt->force_pwchange) | |
127 | disable_forwarding(); | |
128 | return (result && ok); | |
129 | } | |
130 | ||
131 | #ifdef BSD_AUTH | |
132 | static void | |
133 | warn_expiry(Authctxt *authctxt, auth_session_t *as) | |
134 | { | |
135 | char buf[256]; | |
136 | quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; | |
137 | ||
138 | pwwarntime = acwarntime = TWO_WEEKS; | |
139 | ||
140 | pwtimeleft = auth_check_change(as); | |
141 | actimeleft = auth_check_expire(as); | |
142 | #ifdef HAVE_LOGIN_CAP | |
143 | if (authctxt->valid) { | |
144 | pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, | |
145 | TWO_WEEKS); | |
146 | acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, | |
147 | TWO_WEEKS); | |
148 | } | |
149 | #endif | |
150 | if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { | |
151 | daysleft = pwtimeleft / DAY + 1; | |
152 | snprintf(buf, sizeof(buf), | |
153 | "Your password will expire in %lld day%s.\n", | |
154 | daysleft, daysleft == 1 ? "" : "s"); | |
155 | buffer_append(&loginmsg, buf, strlen(buf)); | |
156 | } | |
157 | if (actimeleft != 0 && actimeleft < acwarntime) { | |
158 | daysleft = actimeleft / DAY + 1; | |
159 | snprintf(buf, sizeof(buf), | |
160 | "Your account will expire in %lld day%s.\n", | |
161 | daysleft, daysleft == 1 ? "" : "s"); | |
162 | buffer_append(&loginmsg, buf, strlen(buf)); | |
163 | } | |
164 | } | |
165 | ||
166 | int | |
167 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
168 | { | |
169 | struct passwd *pw = authctxt->pw; | |
170 | auth_session_t *as; | |
171 | static int expire_checked = 0; | |
172 | ||
173 | as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh", | |
174 | (char *)password); | |
175 | if (as == NULL) | |
176 | return (0); | |
177 | if (auth_getstate(as) & AUTH_PWEXPIRED) { | |
178 | auth_close(as); | |
179 | disable_forwarding(); | |
180 | authctxt->force_pwchange = 1; | |
181 | return (1); | |
182 | } else { | |
183 | if (!expire_checked) { | |
184 | expire_checked = 1; | |
185 | warn_expiry(authctxt, as); | |
186 | } | |
187 | return (auth_close(as)); | |
188 | } | |
189 | } | |
190 | #elif !defined(CUSTOM_SYS_AUTH_PASSWD) | |
191 | int | |
192 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
193 | { | |
194 | struct passwd *pw = authctxt->pw; | |
195 | char *encrypted_password; | |
196 | ||
197 | /* Just use the supplied fake password if authctxt is invalid */ | |
198 | char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; | |
199 | ||
200 | /* Check for users with no password. */ | |
201 | if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) | |
202 | return (1); | |
203 | ||
204 | /* Encrypt the candidate password using the proper salt. */ | |
205 | encrypted_password = xcrypt(password, | |
206 | (pw_password[0] && pw_password[1]) ? pw_password : "xx"); | |
207 | ||
208 | /* | |
209 | * Authentication is accepted if the encrypted passwords | |
210 | * are identical. | |
211 | */ | |
212 | return (strcmp(encrypted_password, pw_password) == 0); | |
213 | } | |
214 | #endif |