/* $NetBSD: auth-passwd.c,v 1.11.2.1 2023/12/25 12:31:02 martin Exp $ */ /* $OpenBSD: auth-passwd.c,v 1.48 2020/10/18 11:32:01 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * Password authentication. This file contains the functions to check whether * the password is valid for the user. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * Copyright (c) 1999 Dug Song. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" __RCSID("$NetBSD: auth-passwd.c,v 1.11.2.1 2023/12/25 12:31:02 martin Exp $"); #include #include #include #include #include #include #include #include "packet.h" #include "sshbuf.h" #include "ssherr.h" #include "log.h" #include "misc.h" #include "servconf.h" #include "sshkey.h" #include "hostfile.h" #include "auth.h" #include "auth-options.h" extern struct sshbuf *loginmsg; extern ServerOptions options; int sys_auth_passwd(struct ssh *, const char *); #ifdef HAVE_LOGIN_CAP extern login_cap_t *lc; #endif #define DAY (24L * 60 * 60) /* 1 day in seconds */ #define TWO_WEEKS (2L * 7 * DAY) /* 2 weeks in seconds */ #define MAX_PASSWORD_LEN 1024 /* * Tries to authenticate the user using password. Returns true if * authentication succeeds. */ int auth_password(struct ssh *ssh, const char *password) { Authctxt *authctxt = ssh->authctxt; struct passwd *pw = authctxt->pw; int ok = authctxt->valid; if (strlen(password) > MAX_PASSWORD_LEN) return 0; if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) ok = 0; if (*password == '\0' && options.permit_empty_passwd == 0) return 0; #ifdef KRB5 if (options.kerberos_authentication == 1) { int ret = auth_krb5_password(authctxt, password); if (ret == 1 || ret == 0) return ret && ok; /* Fall back to ordinary passwd authentication. */ } #endif #ifdef USE_PAM if (options.use_pam) return (sshpam_auth_passwd(authctxt, password) && ok); #endif return (sys_auth_passwd(ssh, password) && ok); } #ifdef BSD_AUTH static void warn_expiry(Authctxt *authctxt, auth_session_t *as) { int r; quad_t pwtimeleft, actimeleft, daysleft, pwwarntime, acwarntime; pwwarntime = acwarntime = TWO_WEEKS; pwtimeleft = auth_check_change(as); actimeleft = auth_check_expire(as); #ifdef HAVE_LOGIN_CAP if (authctxt->valid) { pwwarntime = login_getcaptime(lc, "password-warn", TWO_WEEKS, TWO_WEEKS); acwarntime = login_getcaptime(lc, "expire-warn", TWO_WEEKS, TWO_WEEKS); } #endif if (pwtimeleft != 0 && pwtimeleft < pwwarntime) { daysleft = pwtimeleft / DAY + 1; if ((r = sshbuf_putf(loginmsg, "Your password will expire in %lld day%s.\n", daysleft, daysleft == 1 ? "" : "s")) != 0) fatal_fr(r, "buffer error"); } if (actimeleft != 0 && actimeleft < acwarntime) { daysleft = actimeleft / DAY + 1; if ((r = sshbuf_putf(loginmsg, "Your account will expire in %lld day%s.\n", daysleft, daysleft == 1 ? "" : "s")) != 0) fatal_fr(r, "buffer error"); } } int sys_auth_passwd(struct ssh *ssh, const char *password) { Authctxt *authctxt = ssh->authctxt; auth_session_t *as; static int expire_checked = 0; as = auth_usercheck(authctxt->pw->pw_name, authctxt->style, "auth-ssh", (char *)password); if (as == NULL) return (0); if (auth_getstate(as) & AUTH_PWEXPIRED) { auth_close(as); auth_restrict_session(ssh); authctxt->force_pwchange = 1; return (1); } else { if (!expire_checked) { expire_checked = 1; warn_expiry(authctxt, as); } return (auth_close(as)); } } #else #define shadow_pw(pw) (pw)->pw_passwd #define xcrypt(a, b) crypt((a), (b)) int sys_auth_passwd(struct ssh *ssh, const char *password) { Authctxt *authctxt = ssh->authctxt; struct passwd *pw = authctxt->pw; char *encrypted_password, *salt = NULL; /* Just use the supplied fake password if authctxt is invalid */ char *pw_password = authctxt->valid ? shadow_pw(pw) : pw->pw_passwd; /* Check for users with no password. */ if (strcmp(pw_password, "") == 0 && strcmp(password, "") == 0) return (1); /* * Encrypt the candidate password using the proper salt, or pass a * NULL and let xcrypt pick one. */ if (authctxt->valid && pw_password[0] && pw_password[1]) salt = pw_password; encrypted_password = xcrypt(password, salt ? salt : "xx"); /* * Authentication is accepted if the encrypted passwords * are identical. */ return encrypted_password != NULL && strcmp(encrypted_password, pw_password) == 0; } #endif