1 /* $OpenBSD: auth-passwd.c,v 1.48 2020/10/18 11:32:01 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 <sys/types.h>
40
41 #include <login_cap.h>
42 #include <pwd.h>
43 #include <stdio.h>
44 #include <string.h>
45 #include <stdarg.h>
46
47 #include "packet.h"
48 #include "sshbuf.h"
49 #include "ssherr.h"
50 #include "log.h"
51 #include "misc.h"
52 #include "servconf.h"
53 #include "sshkey.h"
54 #include "hostfile.h"
55 #include "auth.h"
56 #include "auth-options.h"
57
58 extern struct sshbuf *loginmsg;
59 extern ServerOptions options;
60 int sys_auth_passwd(struct ssh *, const char *);
61
62 extern login_cap_t *lc;
63
64 #define DAY (24L * 60 * 60) /* 1 day in seconds */
65 #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */
66
67 #define MAX_PASSWORD_LEN 1024
68
69 /*
70 * Tries to authenticate the user using password. Returns true if
71 * authentication succeeds.
72 */
73 int
auth_password(struct ssh * ssh,const char * password)74 auth_password(struct ssh *ssh, const char *password)
75 {
76 Authctxt *authctxt = ssh->authctxt;
77 struct passwd *pw = authctxt->pw;
78 int ok = authctxt->valid;
79
80 if (strlen(password) > MAX_PASSWORD_LEN)
81 return 0;
82
83 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES)
84 ok = 0;
85 if (*password == '\0' && options.permit_empty_passwd == 0)
86 return 0;
87 #ifdef KRB5
88 if (options.kerberos_authentication == 1) {
89 int ret = auth_krb5_password(authctxt, password);
90 if (ret == 1 || ret == 0)
91 return ret && ok;
92 /* Fall back to ordinary passwd authentication. */
93 }
94 #endif
95 return (sys_auth_passwd(ssh, password) && ok);
96 }
97
98 static void
warn_expiry(Authctxt * authctxt,auth_session_t * as)99 warn_expiry(Authctxt *authctxt, auth_session_t *as)
100 {
101 int r;
102 quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime;
103
104 pwwarntime = acwarntime = TWO_WEEKS;
105
106 pwtimeleft = auth_check_change(as);
107 actimeleft = auth_check_expire(as);
108 if (authctxt->valid) {
109 pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS,
110 TWO_WEEKS);
111 acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS,
112 TWO_WEEKS);
113 }
114 if (pwtimeleft != 0 && pwtimeleft < pwwarntime) {
115 daysleft = pwtimeleft / DAY + 1;
116 if ((r = sshbuf_putf(loginmsg,
117 "Your password will expire in %lld day%s.\n",
118 daysleft, daysleft == 1 ? "" : "s")) != 0)
119 fatal_fr(r, "buffer error");
120 }
121 if (actimeleft != 0 && actimeleft < acwarntime) {
122 daysleft = actimeleft / DAY + 1;
123 if ((r = sshbuf_putf(loginmsg,
124 "Your account will expire in %lld day%s.\n",
125 daysleft, daysleft == 1 ? "" : "s")) != 0)
126 fatal_fr(r, "buffer error");
127 }
128 }
129
130 int
sys_auth_passwd(struct ssh * ssh,const char * password)131 sys_auth_passwd(struct ssh *ssh, const char *password)
132 {
133 Authctxt *authctxt = ssh->authctxt;
134 auth_session_t *as;
135 static int expire_checked = 0;
136
137 as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh",
138 (char *)password);
139 if (as == NULL)
140 return (0);
141 if (auth_getstate(as) & AUTH_PWEXPIRED) {
142 auth_close(as);
143 auth_restrict_session(ssh);
144 authctxt->force_pwchange = 1;
145 return (1);
146 } else {
147 if (!expire_checked) {
148 expire_checked = 1;
149 warn_expiry(authctxt, as);
150 }
151 return (auth_close(as));
152 }
153 }
154