auth-passwd.c revision 295367
1/* $OpenBSD: auth-passwd.c,v 1.44 2014/07/15 15:54:14 millert 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#include <stdarg.h> 47 48#include "packet.h" 49#include "buffer.h" 50#include "log.h" 51#include "misc.h" 52#include "servconf.h" 53#include "key.h" 54#include "hostfile.h" 55#include "auth.h" 56#include "auth-options.h" 57 58extern Buffer loginmsg; 59extern ServerOptions options; 60 61#ifdef HAVE_LOGIN_CAP 62extern login_cap_t *lc; 63#endif 64 65 66#define DAY (24L * 60 * 60) /* 1 day in seconds */ 67#define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ 68 69void 70disable_forwarding(void) 71{ 72 no_port_forwarding_flag = 1; 73 no_agent_forwarding_flag = 1; 74 no_x11_forwarding_flag = 1; 75} 76 77/* 78 * Tries to authenticate the user using password. Returns true if 79 * authentication succeeds. 80 */ 81int 82auth_password(Authctxt *authctxt, const char *password) 83{ 84 struct passwd * pw = authctxt->pw; 85 int result, ok = authctxt->valid; 86#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 87 static int expire_checked = 0; 88#endif 89 90#ifndef HAVE_CYGWIN 91 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) 92 ok = 0; 93#endif 94 if (*password == '\0' && options.permit_empty_passwd == 0) 95 return 0; 96 97#ifdef KRB5 98 if (options.kerberos_authentication == 1) { 99 int ret = auth_krb5_password(authctxt, password); 100 if (ret == 1 || ret == 0) 101 return ret && ok; 102 /* Fall back to ordinary passwd authentication. */ 103 } 104#endif 105#ifdef HAVE_CYGWIN 106 { 107 HANDLE hToken = cygwin_logon_user(pw, password); 108 109 if (hToken == INVALID_HANDLE_VALUE) 110 return 0; 111 cygwin_set_impersonation_token(hToken); 112 return ok; 113 } 114#endif 115#ifdef USE_PAM 116 if (options.use_pam) 117 return (sshpam_auth_passwd(authctxt, password) && ok); 118#endif 119#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 120 if (!expire_checked) { 121 expire_checked = 1; 122 if (auth_shadow_pwexpired(authctxt)) 123 authctxt->force_pwchange = 1; 124 } 125#endif 126 result = sys_auth_passwd(authctxt, password); 127 if (authctxt->force_pwchange) 128 disable_forwarding(); 129 return (result && ok); 130} 131 132#ifdef BSD_AUTH 133static void 134warn_expiry(Authctxt *authctxt, auth_session_t *as) 135{ 136 char buf[256]; 137 quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; 138 139 pwwarntime = acwarntime = TWO_WEEKS; 140 141 pwtimeleft = auth_check_change(as); 142 actimeleft = auth_check_expire(as); 143#ifdef HAVE_LOGIN_CAP 144 if (authctxt->valid) { 145 pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, 146 TWO_WEEKS); 147 acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, 148 TWO_WEEKS); 149 } 150#endif 151 if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { 152 daysleft = pwtimeleft / DAY + 1; 153 snprintf(buf, sizeof(buf), 154 "Your password will expire in %lld day%s.\n", 155 daysleft, daysleft == 1 ? "" : "s"); 156 buffer_append(&loginmsg, buf, strlen(buf)); 157 } 158 if (actimeleft != 0 && actimeleft < acwarntime) { 159 daysleft = actimeleft / DAY + 1; 160 snprintf(buf, sizeof(buf), 161 "Your account will expire in %lld day%s.\n", 162 daysleft, daysleft == 1 ? "" : "s"); 163 buffer_append(&loginmsg, buf, strlen(buf)); 164 } 165} 166 167int 168sys_auth_passwd(Authctxt *authctxt, const char *password) 169{ 170 struct passwd *pw = authctxt->pw; 171 auth_session_t *as; 172 static int expire_checked = 0; 173 174 as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh", 175 (char *)password); 176 if (as == NULL) 177 return (0); 178 if (auth_getstate(as) & AUTH_PWEXPIRED) { 179 auth_close(as); 180 disable_forwarding(); 181 authctxt->force_pwchange = 1; 182 return (1); 183 } else { 184 if (!expire_checked) { 185 expire_checked = 1; 186 warn_expiry(authctxt, as); 187 } 188 return (auth_close(as)); 189 } 190} 191#elif !defined(CUSTOM_SYS_AUTH_PASSWD) 192int 193sys_auth_passwd(Authctxt *authctxt, const char *password) 194{ 195 struct passwd *pw = authctxt->pw; 196 char *encrypted_password; 197 198 /* Just use the supplied fake password if authctxt is invalid */ 199 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; 200 201 /* Check for users with no password. */ 202 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) 203 return (1); 204 205 /* Encrypt the candidate password using the proper salt. */ 206 encrypted_password = xcrypt(password, 207 (pw_password[0] && pw_password[1]) ? pw_password : "xx"); 208 209 /* 210 * Authentication is accepted if the encrypted passwords 211 * are identical. 212 */ 213 return encrypted_password != NULL && 214 strcmp(encrypted_password, pw_password) == 0; 215} 216#endif 217