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1 | /* $OpenBSD: auth-passwd.c,v 1.39 2006/08/01 23:22:47 stevesk 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 | ||
47 | #include "packet.h" | |
48 | #include "buffer.h" | |
49 | #include "log.h" | |
50 | #include "servconf.h" | |
51 | #include "auth.h" | |
52 | #include "auth-options.h" | |
53 | ||
54 | extern Buffer loginmsg; | |
55 | extern ServerOptions options; | |
56 | ||
57 | #ifdef HAVE_LOGIN_CAP | |
58 | extern login_cap_t *lc; | |
59 | #endif | |
60 | ||
61 | ||
62 | #define DAY (24L * 60 * 60) /* 1 day in seconds */ | |
63 | #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ | |
64 | ||
65 | void | |
66 | disable_forwarding(void) | |
67 | { | |
68 | no_port_forwarding_flag = 1; | |
69 | no_agent_forwarding_flag = 1; | |
70 | no_x11_forwarding_flag = 1; | |
71 | } | |
72 | ||
73 | /* | |
74 | * Tries to authenticate the user using password. Returns true if | |
75 | * authentication succeeds. | |
76 | */ | |
77 | int | |
78 | auth_password(Authctxt *authctxt, const char *password) | |
79 | { | |
80 | struct passwd * pw = authctxt->pw; | |
81 | int result, ok = authctxt->valid; | |
82 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
83 | static int expire_checked = 0; | |
84 | #endif | |
85 | ||
86 | #ifndef HAVE_CYGWIN | |
87 | if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) | |
88 | ok = 0; | |
89 | #endif | |
90 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
91 | return 0; | |
92 | ||
93 | #ifdef KRB5 | |
94 | if (options.kerberos_authentication == 1) { | |
95 | int ret = auth_krb5_password(authctxt, password); | |
96 | if (ret == 1 || ret == 0) | |
97 | return ret && ok; | |
98 | /* Fall back to ordinary passwd authentication. */ | |
99 | } | |
100 | #endif | |
101 | #ifdef HAVE_CYGWIN | |
102 | if (is_winnt) { | |
103 | HANDLE hToken = cygwin_logon_user(pw, password); | |
104 | ||
105 | if (hToken == INVALID_HANDLE_VALUE) | |
106 | return 0; | |
107 | cygwin_set_impersonation_token(hToken); | |
108 | return ok; | |
109 | } | |
110 | #endif | |
111 | #ifdef USE_PAM | |
112 | if (options.use_pam) | |
113 | return (sshpam_auth_passwd(authctxt, password) && ok); | |
114 | #endif | |
115 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
116 | if (!expire_checked) { | |
117 | expire_checked = 1; | |
118 | if (auth_shadow_pwexpired(authctxt)) | |
119 | authctxt->force_pwchange = 1; | |
120 | } | |
121 | #endif | |
122 | result = sys_auth_passwd(authctxt, password); | |
123 | if (authctxt->force_pwchange) | |
124 | disable_forwarding(); | |
125 | return (result && ok); | |
126 | } | |
127 | ||
128 | #ifdef BSD_AUTH | |
129 | static void | |
130 | warn_expiry(Authctxt *authctxt, auth_session_t *as) | |
131 | { | |
132 | char buf[256]; | |
133 | quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; | |
134 | ||
135 | pwwarntime = acwarntime = TWO_WEEKS; | |
136 | ||
137 | pwtimeleft = auth_check_change(as); | |
138 | actimeleft = auth_check_expire(as); | |
139 | #ifdef HAVE_LOGIN_CAP | |
140 | if (authctxt->valid) { | |
141 | pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, | |
142 | TWO_WEEKS); | |
143 | acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, | |
144 | TWO_WEEKS); | |
145 | } | |
146 | #endif | |
147 | if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { | |
148 | daysleft = pwtimeleft / DAY + 1; | |
149 | snprintf(buf, sizeof(buf), | |
150 | "Your password will expire in %lld day%s.\n", | |
151 | daysleft, daysleft == 1 ? "" : "s"); | |
152 | buffer_append(&loginmsg, buf, strlen(buf)); | |
153 | } | |
154 | if (actimeleft != 0 && actimeleft < acwarntime) { | |
155 | daysleft = actimeleft / DAY + 1; | |
156 | snprintf(buf, sizeof(buf), | |
157 | "Your account will expire in %lld day%s.\n", | |
158 | daysleft, daysleft == 1 ? "" : "s"); | |
159 | buffer_append(&loginmsg, buf, strlen(buf)); | |
160 | } | |
161 | } | |
162 | ||
163 | int | |
164 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
165 | { | |
166 | struct passwd *pw = authctxt->pw; | |
167 | auth_session_t *as; | |
168 | static int expire_checked = 0; | |
169 | ||
170 | as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh", | |
171 | (char *)password); | |
172 | if (as == NULL) | |
173 | return (0); | |
174 | if (auth_getstate(as) & AUTH_PWEXPIRED) { | |
175 | auth_close(as); | |
176 | disable_forwarding(); | |
177 | authctxt->force_pwchange = 1; | |
178 | return (1); | |
179 | } else { | |
180 | if (!expire_checked) { | |
181 | expire_checked = 1; | |
182 | warn_expiry(authctxt, as); | |
183 | } | |
184 | return (auth_close(as)); | |
185 | } | |
186 | } | |
187 | #elif !defined(CUSTOM_SYS_AUTH_PASSWD) | |
188 | int | |
189 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
190 | { | |
191 | struct passwd *pw = authctxt->pw; | |
192 | char *encrypted_password; | |
193 | ||
194 | /* Just use the supplied fake password if authctxt is invalid */ | |
195 | char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; | |
196 | ||
197 | /* Check for users with no password. */ | |
198 | if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) | |
199 | return (1); | |
200 | ||
201 | /* Encrypt the candidate password using the proper salt. */ | |
202 | encrypted_password = xcrypt(password, | |
203 | (pw_password[0] && pw_password[1]) ? pw_password : "xx"); | |
204 | ||
205 | /* | |
206 | * Authentication is accepted if the encrypted passwords | |
207 | * are identical. | |
208 | */ | |
209 | return (strcmp(encrypted_password, pw_password) == 0); | |
210 | } | |
211 | #endif |