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 1.31 2004/01/30 09:48:57 markus Exp $"); 40 RCSID("$FreeBSD$"); 41 42 #include "packet.h" 43 #include "log.h" 44 #include "servconf.h" 45 #include "auth.h" 46 #include "auth-options.h" 47 48 extern ServerOptions options; 49 int sys_auth_passwd(Authctxt *, const char *); 50 51 void 52 disable_forwarding(void) 53 { 54 no_port_forwarding_flag = 1; 55 no_agent_forwarding_flag = 1; 56 no_x11_forwarding_flag = 1; 57 } 58 59 /* 60 * Tries to authenticate the user using password. Returns true if 61 * authentication succeeds. 62 */ 63 int 64 auth_password(Authctxt *authctxt, const char *password) 65 { 66 struct passwd * pw = authctxt->pw; 67 int ok = authctxt->valid; 68 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 69 static int expire_checked = 0; 70 #endif 71 72 #ifndef HAVE_CYGWIN 73 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) 74 ok = 0; 75 #endif 76 if (*password == '\0' && options.permit_empty_passwd == 0) 77 return 0; 78 79 #ifdef KRB5 80 if (options.kerberos_authentication == 1) { 81 int ret = auth_krb5_password(authctxt, password); 82 if (ret == 1 || ret == 0) 83 return ret && ok; 84 /* Fall back to ordinary passwd authentication. */ 85 } 86 #endif 87 #ifdef HAVE_CYGWIN 88 if (is_winnt) { 89 HANDLE hToken = cygwin_logon_user(pw, password); 90 91 if (hToken == INVALID_HANDLE_VALUE) 92 return 0; 93 cygwin_set_impersonation_token(hToken); 94 return ok; 95 } 96 #endif 97 #ifdef USE_PAM 98 if (options.use_pam) 99 return (sshpam_auth_passwd(authctxt, password) && ok); 100 #endif 101 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 102 if (!expire_checked) { 103 expire_checked = 1; 104 if (auth_shadow_pwexpired(authctxt)) { 105 disable_forwarding(); 106 authctxt->force_pwchange = 1; 107 } 108 } 109 #endif 110 111 return (sys_auth_passwd(authctxt, password) && ok); 112 } 113 114 #ifdef BSD_AUTH 115 int 116 sys_auth_passwd(Authctxt *authctxt, const char *password) 117 { 118 struct passwd *pw = authctxt->pw; 119 auth_session_t *as; 120 121 as = auth_usercheck(pw->pw_name, authctxt->style, "auth-ssh", 122 (char *)password); 123 if (auth_getstate(as) & AUTH_PWEXPIRED) { 124 auth_close(as); 125 disable_forwarding(); 126 authctxt->force_pwchange = 1; 127 return (1); 128 } else { 129 return (auth_close(as)); 130 } 131 } 132 #elif !defined(CUSTOM_SYS_AUTH_PASSWD) 133 int 134 sys_auth_passwd(Authctxt *authctxt, const char *password) 135 { 136 struct passwd *pw = authctxt->pw; 137 char *encrypted_password; 138 139 /* Just use the supplied fake password if authctxt is invalid */ 140 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; 141 142 /* Check for users with no password. */ 143 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) 144 return (1); 145 146 /* Encrypt the candidate password using the proper salt. */ 147 encrypted_password = xcrypt(password, 148 (pw_password[0] && pw_password[1]) ? pw_password : "xx"); 149 150 /* 151 * Authentication is accepted if the encrypted passwords 152 * are identical. 153 */ 154 return (strcmp(encrypted_password, pw_password) == 0); 155 } 156 #endif 157