1 /* $NetBSD: auth-passwd.c,v 1.9 2018/04/07 00:26:12 christos Exp $ */ 2 /* $OpenBSD: auth-passwd.c,v 1.46 2018/03/03 03:15:51 djm Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Password authentication. This file contains the functions to check whether 8 * the password is valid for the user. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * Copyright (c) 1999 Dug Song. All rights reserved. 17 * Copyright (c) 2000 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 __RCSID("$NetBSD: auth-passwd.c,v 1.9 2018/04/07 00:26:12 christos Exp $"); 42 #include <sys/types.h> 43 44 #include <login_cap.h> 45 #include <pwd.h> 46 #include <stdio.h> 47 #include <string.h> 48 #include <stdarg.h> 49 #include <unistd.h> 50 51 #include "packet.h" 52 #include "buffer.h" 53 #include "log.h" 54 #include "misc.h" 55 #include "servconf.h" 56 #include "key.h" 57 #include "hostfile.h" 58 #include "auth.h" 59 #include "auth-options.h" 60 61 extern Buffer loginmsg; 62 extern ServerOptions options; 63 int sys_auth_passwd(struct ssh *, const char *); 64 65 #ifdef HAVE_LOGIN_CAP 66 extern login_cap_t *lc; 67 #endif 68 69 #define DAY (24L * 60 * 60) /* 1 day in seconds */ 70 #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ 71 72 #define MAX_PASSWORD_LEN 1024 73 74 /* 75 * Tries to authenticate the user using password. Returns true if 76 * authentication succeeds. 77 */ 78 int 79 auth_password(struct ssh *ssh, const char *password) 80 { 81 Authctxt *authctxt = ssh->authctxt; 82 struct passwd *pw = authctxt->pw; 83 int ok = authctxt->valid; 84 85 if (strlen(password) > MAX_PASSWORD_LEN) 86 return 0; 87 88 if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) 89 ok = 0; 90 if (*password == '\0' && options.permit_empty_passwd == 0) 91 return 0; 92 #ifdef KRB5 93 if (options.kerberos_authentication == 1) { 94 int ret = auth_krb5_password(authctxt, password); 95 if (ret == 1 || ret == 0) 96 return ret && ok; 97 /* Fall back to ordinary passwd authentication. */ 98 } 99 #endif 100 101 #ifdef USE_PAM 102 if (options.use_pam) 103 return (sshpam_auth_passwd(authctxt, password) && ok); 104 #endif 105 return (sys_auth_passwd(ssh, password) && ok); 106 } 107 108 #ifdef BSD_AUTH 109 static void 110 warn_expiry(Authctxt *authctxt, auth_session_t *as) 111 { 112 char buf[256]; 113 quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; 114 115 pwwarntime = acwarntime = TWO_WEEKS; 116 117 pwtimeleft = auth_check_change(as); 118 actimeleft = auth_check_expire(as); 119 #ifdef HAVE_LOGIN_CAP 120 if (authctxt->valid) { 121 pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, 122 TWO_WEEKS); 123 acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, 124 TWO_WEEKS); 125 } 126 #endif 127 if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { 128 daysleft = pwtimeleft / DAY + 1; 129 snprintf(buf, sizeof(buf), 130 "Your password will expire in %lld day%s.\n", 131 daysleft, daysleft == 1 ? "" : "s"); 132 buffer_append(&loginmsg, buf, strlen(buf)); 133 } 134 if (actimeleft != 0 && actimeleft < acwarntime) { 135 daysleft = actimeleft / DAY + 1; 136 snprintf(buf, sizeof(buf), 137 "Your account will expire in %lld day%s.\n", 138 daysleft, daysleft == 1 ? "" : "s"); 139 buffer_append(&loginmsg, buf, strlen(buf)); 140 } 141 } 142 143 int 144 sys_auth_passwd(struct ssh *ssh, const char *password) 145 { 146 Authctxt *authctxt = ssh->authctxt; 147 auth_session_t *as; 148 static int expire_checked = 0; 149 150 as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh", 151 (char *)password); 152 if (as == NULL) 153 return (0); 154 if (auth_getstate(as) & AUTH_PWEXPIRED) { 155 auth_close(as); 156 auth_restrict_session(ssh); 157 authctxt->force_pwchange = 1; 158 return (1); 159 } else { 160 if (!expire_checked) { 161 expire_checked = 1; 162 warn_expiry(authctxt, as); 163 } 164 return (auth_close(as)); 165 } 166 } 167 #else 168 169 #define shadow_pw(pw) (pw)->pw_passwd 170 #define xcrypt(a, b) crypt((a), (b)) 171 172 int 173 sys_auth_passwd(struct ssh *ssh, const char *password) 174 { 175 Authctxt *authctxt = ssh->authctxt; 176 struct passwd *pw = authctxt->pw; 177 char *encrypted_password, *salt = NULL; 178 179 /* Just use the supplied fake password if authctxt is invalid */ 180 char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; 181 182 /* Check for users with no password. */ 183 if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) 184 return (1); 185 186 /* 187 * Encrypt the candidate password using the proper salt, or pass a 188 * NULL and let xcrypt pick one. 189 */ 190 if (authctxt->valid && pw_password[0] && pw_password[1]) 191 salt = pw_password; 192 encrypted_password = xcrypt(password, salt ? salt : "xx"); 193 194 /* 195 * Authentication is accepted if the encrypted passwords 196 * are identical. 197 */ 198 return encrypted_password != NULL && 199 strcmp(encrypted_password, pw_password) == 0; 200 } 201 #endif 202