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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
2
3auth-passwd.c
4
5Author: Tatu Ylonen <ylo@cs.hut.fi>
6
7Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 All rights reserved
9
10Created: Sat Mar 18 05:11:38 1995 ylo
11
12Password authentication. This file contains the functions to check whether
13the password is valid for the user.
14
15*/
16
17#include "includes.h"
Damien Millerdd1c7ba1999-11-19 15:53:20 +110018
19#ifndef HAVE_PAM
20
21RCSID("$Id: auth-passwd.c,v 1.5 1999/11/19 04:53:20 damien Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100022
23#include "packet.h"
24#include "ssh.h"
25#include "servconf.h"
26#include "xmalloc.h"
Damien Miller2cb210f1999-11-13 15:40:10 +110027#include "config.h"
28
29#ifdef HAVE_SHADOW_H
30#include <shadow.h>
31#endif
32
Damien Millerdd1c7ba1999-11-19 15:53:20 +110033#ifdef HAVE_MD5_PASSWORDS
34#include "md5crypt.h"
35#endif
36
Damien Miller2cb210f1999-11-13 15:40:10 +110037/* Don't need anything from here if we are using PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100038
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039/* Tries to authenticate the user using password. Returns true if
40 authentication succeeds. */
41
42int auth_password(struct passwd *pw, const char *password)
43{
44 extern ServerOptions options;
45 char *encrypted_password;
Damien Miller2cb210f1999-11-13 15:40:10 +110046#ifdef HAVE_SHADOW_H
47 struct spwd *spw;
48#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +100049
50 if (pw->pw_uid == 0 && options.permit_root_login == 2)
51 {
52 /*packet_send_debug("Server does not permit root login with password.");*/
53 return 0;
54 }
55
56 if (*password == '\0' && options.permit_empty_passwd == 0)
57 {
58 /*packet_send_debug("Server does not permit empty password login.");*/
59 return 0;
60 }
61
62 /* deny if no user. */
63 if (pw == NULL)
64 return 0;
65
Damien Millerd4a8b7e1999-10-27 13:42:43 +100066#ifdef SKEY
67 if (options.skey_authentication == 1) {
68 if (strncasecmp(password, "s/key", 5) == 0) {
69 char *skeyinfo = skey_keyinfo(pw->pw_name);
70 if(skeyinfo == NULL){
71 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
72 skeyinfo = skey_fake_keyinfo(pw->pw_name);
73 }
74 if(skeyinfo != NULL)
75 packet_send_debug(skeyinfo);
76 /* Try again. */
77 return 0;
78 }
79 else if (skey_haskey(pw->pw_name) == 0 &&
80 skey_passcheck(pw->pw_name, (char *)password) != -1) {
81 /* Authentication succeeded. */
82 return 1;
83 }
84 /* Fall back to ordinary passwd authentication. */
85 }
86#endif
87
88#if defined(KRB4)
89 /* Support for Kerberos v4 authentication - Dug Song <dugsong@UMICH.EDU> */
90 if (options.kerberos_authentication)
91 {
92 AUTH_DAT adata;
93 KTEXT_ST tkt;
94 struct hostent *hp;
95 unsigned long faddr;
Damien Miller5ce662a1999-11-11 17:57:39 +110096 char localhost[MAXHOSTNAMELEN];
97 char phost[INST_SZ];
98 char realm[REALM_SZ];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100099 int r;
100
101 /* Try Kerberos password authentication only for non-root
102 users and only if Kerberos is installed. */
103 if (pw->pw_uid != 0 && krb_get_lrealm(realm, 1) == KSUCCESS) {
104
105 /* Set up our ticket file. */
Damien Miller5ce662a1999-11-11 17:57:39 +1100106 if (!krb4_init(pw->pw_uid)) {
107 log("Couldn't initialize Kerberos ticket file for %s!", pw->pw_name);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108 goto kerberos_auth_failure;
109 }
110 /* Try to get TGT using our password. */
111 r = krb_get_pw_in_tkt((char *)pw->pw_name, "", realm, "krbtgt", realm,
112 DEFAULT_TKT_LIFE, (char *)password);
113 if (r != INTK_OK) {
114 packet_send_debug("Kerberos V4 password authentication for %s "
115 "failed: %s", pw->pw_name, krb_err_txt[r]);
116 goto kerberos_auth_failure;
117 }
118 /* Successful authentication. */
Damien Miller5ce662a1999-11-11 17:57:39 +1100119 chown(tkt_string(), pw->pw_uid, pw->pw_gid);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120
121 /* Now that we have a TGT, try to get a local "rcmd" ticket to
122 ensure that we are not talking to a bogus Kerberos server. */
Damien Miller5ce662a1999-11-11 17:57:39 +1100123 (void) gethostname(localhost, sizeof(localhost));
124 (void) strlcpy(phost, (char *)krb_get_phost(localhost), INST_SZ);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000125 r = krb_mk_req(&tkt, KRB4_SERVICE_NAME, phost, realm, 33);
126
127 if (r == KSUCCESS) {
128 if (!(hp = gethostbyname(localhost))) {
129 log("Couldn't get local host address!");
130 goto kerberos_auth_failure;
131 }
132 memmove((void *)&faddr, (void *)hp->h_addr, sizeof(faddr));
133
134 /* Verify our "rcmd" ticket. */
135 r = krb_rd_req(&tkt, KRB4_SERVICE_NAME, phost, faddr, &adata, "");
136 if (r == RD_AP_UNDEC) {
137 /* Probably didn't have a srvtab on localhost. Allow login. */
138 log("Kerberos V4 TGT for %s unverifiable, no srvtab installed? "
139 "krb_rd_req: %s", pw->pw_name, krb_err_txt[r]);
140 }
141 else if (r != KSUCCESS) {
142 log("Kerberos V4 %s ticket unverifiable: %s",
143 KRB4_SERVICE_NAME, krb_err_txt[r]);
144 goto kerberos_auth_failure;
145 }
146 }
147 else if (r == KDC_PR_UNKNOWN) {
148 /* Allow login if no rcmd service exists, but log the error. */
149 log("Kerberos V4 TGT for %s unverifiable: %s; %s.%s "
150 "not registered, or srvtab is wrong?", pw->pw_name,
151 krb_err_txt[r], KRB4_SERVICE_NAME, phost);
152 }
153 else {
154 /* TGT is bad, forget it. Possibly spoofed! */
155 packet_send_debug("WARNING: Kerberos V4 TGT possibly spoofed for"
156 "%s: %s", pw->pw_name, krb_err_txt[r]);
157 goto kerberos_auth_failure;
158 }
159
160 /* Authentication succeeded. */
161 return 1;
162
163 kerberos_auth_failure:
Damien Miller5ce662a1999-11-11 17:57:39 +1100164 krb4_cleanup_proc(NULL);
165
166 if (!options.kerberos_or_local_passwd)
167 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000168 }
169 else {
170 /* Logging in as root or no local Kerberos realm. */
171 packet_send_debug("Unable to authenticate to Kerberos.");
172 }
173 /* Fall back to ordinary passwd authentication. */
174 }
175#endif /* KRB4 */
176
177 /* Check for users with no password. */
178 if (strcmp(password, "") == 0 && strcmp(pw->pw_passwd, "") == 0)
179 {
180 packet_send_debug("Login permitted without a password because the account has no password.");
181 return 1; /* The user has no password and an empty password was tried. */
182 }
183
Damien Miller2cb210f1999-11-13 15:40:10 +1100184#ifdef HAVE_SHADOW_H
185 spw = getspnam(pw->pw_name);
186 if (spw == NULL)
187 return(0);
188
189 if ((spw->sp_namp == NULL) || (strcmp(pw->pw_name, spw->sp_namp) != 0))
190 fatal("Shadow lookup returned garbage.");
191
192 if (strlen(spw->sp_pwdp) < 3)
193 return(0);
194
195 /* Encrypt the candidate password using the proper salt. */
Damien Millerdd1c7ba1999-11-19 15:53:20 +1100196#ifdef HAVE_MD5_PASSWORDS
197 if (is_md5_salt(spw->sp_pwdp))
198 encrypted_password = md5_crypt(password, spw->sp_pwdp);
199 else
200 encrypted_password = crypt(password, spw->sp_pwdp);
201#else /* HAVE_MD5_PASSWORDS */
Damien Miller2cb210f1999-11-13 15:40:10 +1100202 encrypted_password = crypt(password, spw->sp_pwdp);
Damien Millerdd1c7ba1999-11-19 15:53:20 +1100203#endif /* HAVE_MD5_PASSWORDS */
Damien Miller2cb210f1999-11-13 15:40:10 +1100204
205 /* Authentication is accepted if the encrypted passwords are identical. */
206 return (strcmp(encrypted_password, spw->sp_pwdp) == 0);
207#else /* !HAVE_SHADOW_H */
208
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000209 /* Encrypt the candidate password using the proper salt. */
210 encrypted_password = crypt(password,
211 (pw->pw_passwd[0] && pw->pw_passwd[1]) ?
212 pw->pw_passwd : "xx");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000213 /* Authentication is accepted if the encrypted passwords are identical. */
214 return (strcmp(encrypted_password, pw->pw_passwd) == 0);
Damien Miller2cb210f1999-11-13 15:40:10 +1100215#endif /* !HAVE_SHADOW_H */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000216}
Damien Miller2cb210f1999-11-13 15:40:10 +1100217
218#endif /* !HAVE_PAM */