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Diffstat (limited to 'auth-passwd.c')
| -rw-r--r-- | auth-passwd.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/auth-passwd.c b/auth-passwd.c new file mode 100644 index 0000000..347d91e --- /dev/null +++ b/auth-passwd.c @@ -0,0 +1,223 @@ +/* $OpenBSD: auth-passwd.c,v 1.48 2020/10/18 11:32:01 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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" + +#include <sys/types.h> + +#include <pwd.h> +#include <stdio.h> +#include <string.h> +#include <stdarg.h> + +#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; + +#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 result, ok = authctxt->valid; +#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) + static int expire_checked = 0; +#endif + + if (strlen(password) > MAX_PASSWORD_LEN) + return 0; + +#ifndef HAVE_CYGWIN + if (pw->pw_uid == 0 && options.permit_root_login != PERMIT_YES) + ok = 0; +#endif + 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 HAVE_CYGWIN + { + HANDLE hToken = cygwin_logon_user(pw, password); + + if (hToken == INVALID_HANDLE_VALUE) + return 0; + cygwin_set_impersonation_token(hToken); + return ok; + } +#endif +#ifdef USE_PAM + if (options.use_pam) + return (sshpam_auth_passwd(authctxt, password) && ok); +#endif +#if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) + if (!expire_checked) { + expire_checked = 1; + if (auth_shadow_pwexpired(authctxt)) + authctxt->force_pwchange = 1; + } +#endif + result = sys_auth_passwd(ssh, password); + if (authctxt->force_pwchange) + auth_restrict_session(ssh); + return (result && 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)); + } +} +#elif !defined(CUSTOM_SYS_AUTH_PASSWD) +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; + + if (pw_password == NULL) + return 0; + + /* 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); + + /* + * Authentication is accepted if the encrypted passwords + * are identical. + */ + return encrypted_password != NULL && + strcmp(encrypted_password, pw_password) == 0; +} +#endif |