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 1.34 2005/07/19 15:32:26 otto Exp $"); 40 RCSID("$FreeBSD$"); 41 42 #include "packet.h" 43 #include "buffer.h" 44 #include "log.h" 45 #include "servconf.h" 46 #include "auth.h" 47 #include "auth-options.h" 48 49 extern Buffer loginmsg; 50 extern ServerOptions options; 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 result, 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 authctxt->force_pwchange = 1; 115 } 116 #endif 117 result = sys_auth_passwd(authctxt, password); 118 if (authctxt->force_pwchange) 119 disable_forwarding(); 120 return (result && 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 (as == NULL) 168 return (0); 169 if (auth_getstate(as) & AUTH_PWEXPIRED) { 170 auth_close(as); 171 disable_forwarding(); 172 authctxt->force_pwchange = 1; 173 return (1); 174 } else { 175 if (!expire_checked) { 176 expire_checked = 1; 177 warn_expiry(authctxt, as); 178 } 179 return (auth_close(as)); 180 } 181 } 182 #elif !defined(CUSTOM_SYS_AUTH_PASSWD) 183 int 184 sys_auth_passwd(Authctxt *authctxt, const char *password) 185 { 186 struct passwd *pw = authctxt->pw; 187 char *encrypted_password; 188 189 /* Just use the supplied fake password if authctxt is invalid */ 190 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; 191 192 /* Check for users with no password. */ 193 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) 194 return (1); 195 196 /* Encrypt the candidate password using the proper salt. */ 197 encrypted_password = xcrypt(password, 198 (pw_password[0] && pw_password[1]) ? pw_password : "xx"); 199 200 /* 201 * Authentication is accepted if the encrypted passwords 202 * are identical. 203 */ 204 return (strcmp(encrypted_password, pw_password) == 0); 205 } 206 #endif 207