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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 1.33 2005/01/24 11:47:13 dtucker Exp $"); | |
40 | ||
41 | #include "packet.h" | |
42 | #include "buffer.h" | |
43 | #include "log.h" | |
44 | #include "servconf.h" | |
45 | #include "auth.h" | |
46 | #include "auth-options.h" | |
47 | ||
48 | extern Buffer loginmsg; | |
49 | extern ServerOptions options; | |
50 | int sys_auth_passwd(Authctxt *, const char *); | |
51 | ||
52 | #ifdef HAVE_LOGIN_CAP | |
53 | extern login_cap_t *lc; | |
54 | #endif | |
55 | ||
56 | ||
57 | #define DAY (24L * 60 * 60) /* 1 day in seconds */ | |
58 | #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ | |
59 | ||
60 | void | |
61 | disable_forwarding(void) | |
62 | { | |
63 | no_port_forwarding_flag = 1; | |
64 | no_agent_forwarding_flag = 1; | |
65 | no_x11_forwarding_flag = 1; | |
66 | } | |
67 | ||
68 | /* | |
69 | * Tries to authenticate the user using password. Returns true if | |
70 | * authentication succeeds. | |
71 | */ | |
72 | int | |
73 | auth_password(Authctxt *authctxt, const char *password) | |
74 | { | |
75 | struct passwd * pw = authctxt->pw; | |
76 | int ok = authctxt->valid; | |
77 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
78 | static int expire_checked = 0; | |
79 | #endif | |
80 | ||
81 | #ifndef HAVE_CYGWIN | |
82 | if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) | |
83 | ok = 0; | |
84 | #endif | |
85 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
86 | return 0; | |
87 | ||
88 | #ifdef KRB5 | |
89 | if (options.kerberos_authentication == 1) { | |
90 | int ret = auth_krb5_password(authctxt, password); | |
91 | if (ret == 1 || ret == 0) | |
92 | return ret && ok; | |
93 | /* Fall back to ordinary passwd authentication. */ | |
94 | } | |
95 | #endif | |
96 | #ifdef HAVE_CYGWIN | |
97 | if (is_winnt) { | |
98 | HANDLE hToken = cygwin_logon_user(pw, password); | |
99 | ||
100 | if (hToken == INVALID_HANDLE_VALUE) | |
101 | return 0; | |
102 | cygwin_set_impersonation_token(hToken); | |
103 | return ok; | |
104 | } | |
105 | #endif | |
106 | #ifdef USE_PAM | |
107 | if (options.use_pam) | |
108 | return (sshpam_auth_passwd(authctxt, password) && ok); | |
109 | #endif | |
110 | #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) | |
111 | if (!expire_checked) { | |
112 | expire_checked = 1; | |
113 | if (auth_shadow_pwexpired(authctxt)) { | |
114 | disable_forwarding(); | |
115 | authctxt->force_pwchange = 1; | |
116 | } | |
117 | } | |
118 | #endif | |
119 | ||
120 | return (sys_auth_passwd(authctxt, password) && ok); | |
121 | } | |
122 | ||
123 | #ifdef BSD_AUTH | |
124 | static void | |
125 | warn_expiry(Authctxt *authctxt, auth_session_t *as) | |
126 | { | |
127 | char buf[256]; | |
128 | quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; | |
129 | ||
130 | pwwarntime = acwarntime = TWO_WEEKS; | |
131 | ||
132 | pwtimeleft = auth_check_change(as); | |
133 | actimeleft = auth_check_expire(as); | |
134 | #ifdef HAVE_LOGIN_CAP | |
135 | if (authctxt->valid) { | |
136 | pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, | |
137 | TWO_WEEKS); | |
138 | acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, | |
139 | TWO_WEEKS); | |
140 | } | |
141 | #endif | |
142 | if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { | |
143 | daysleft = pwtimeleft / DAY + 1; | |
144 | snprintf(buf, sizeof(buf), | |
145 | "Your password will expire in %lld day%s.\n", | |
146 | daysleft, daysleft == 1 ? "" : "s"); | |
147 | buffer_append(&loginmsg, buf, strlen(buf)); | |
148 | } | |
149 | if (actimeleft != 0 && actimeleft < acwarntime) { | |
150 | daysleft = actimeleft / DAY + 1; | |
151 | snprintf(buf, sizeof(buf), | |
152 | "Your account will expire in %lld day%s.\n", | |
153 | daysleft, daysleft == 1 ? "" : "s"); | |
154 | buffer_append(&loginmsg, buf, strlen(buf)); | |
155 | } | |
156 | } | |
157 | ||
158 | int | |
159 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
160 | { | |
161 | struct passwd *pw = authctxt->pw; | |
162 | auth_session_t *as; | |
163 | static int expire_checked = 0; | |
164 | ||
165 | as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh", | |
166 | (char *)password); | |
167 | if (auth_getstate(as) & AUTH_PWEXPIRED) { | |
168 | auth_close(as); | |
169 | disable_forwarding(); | |
170 | authctxt->force_pwchange = 1; | |
171 | return (1); | |
172 | } else { | |
173 | if (!expire_checked) { | |
174 | expire_checked = 1; | |
175 | warn_expiry(authctxt, as); | |
176 | } | |
177 | return (auth_close(as)); | |
178 | } | |
179 | } | |
180 | #elif !defined(CUSTOM_SYS_AUTH_PASSWD) | |
181 | int | |
182 | sys_auth_passwd(Authctxt *authctxt, const char *password) | |
183 | { | |
184 | struct passwd *pw = authctxt->pw; | |
185 | char *encrypted_password; | |
186 | ||
187 | /* Just use the supplied fake password if authctxt is invalid */ | |
188 | char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; | |
189 | ||
190 | /* Check for users with no password. */ | |
191 | if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) | |
192 | return (1); | |
193 | ||
194 | /* Encrypt the candidate password using the proper salt. */ | |
195 | encrypted_password = xcrypt(password, | |
196 | (pw_password[0] && pw_password[1]) ? pw_password : "xx"); | |
197 | ||
198 | /* | |
199 | * Authentication is accepted if the encrypted passwords | |
200 | * are identical. | |
201 | */ | |
202 | return (strcmp(encrypted_password, pw_password) == 0); | |
203 | } | |
204 | #endif |