/*
 * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/*
 * -----------------------------------------------------------------------------
 *
 * Author: Markus Moeller (markus_moeller at compuserve.com)
 *
 * Copyright (C) 2007 Markus Moeller. All rights reserved.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
 *
 * -----------------------------------------------------------------------------
 */

#include "squid.h"
#include "util.h"

#if HAVE_LDAP

#include "support.h"

#if HAVE_SASL_H
#include <sasl.h>
#elif HAVE_SASL_SASL_H
#include <sasl/sasl.h>
#elif HAVE_SASL_DARWIN
typedef struct sasl_interact {
    unsigned long id;       /* same as client/user callback ID */
    const char *challenge;  /* presented to user (e.g. OTP challenge) */
    const char *prompt;     /* presented to user (e.g. "Username: ") */
    const char *defresult;  /* default result string */
    const void *result;     /* set to point to result */
    unsigned len;       /* set to length of result */
} sasl_interact_t;

#define SASL_CB_USER         0x4001 /* client user identity to login as */
#define SASL_CB_AUTHNAME     0x4002 /* client authentication name */
#define SASL_CB_PASS         0x4004 /* client passphrase-based secret */
#define SASL_CB_ECHOPROMPT   0x4005 /* challenge and client enterred result */
#define SASL_CB_NOECHOPROMPT 0x4006 /* challenge and client enterred result */
#define SASL_CB_GETREALM     0x4008 /* realm to attempt authentication in */
#define SASL_CB_LIST_END   0    /* end of list */
#endif

#if HAVE_SASL_H || HAVE_SASL_SASL_H || HAVE_SASL_DARWIN
void *lutil_sasl_defaults(
    LDAP * ld,
    char *mech,
    char *realm,
    char *authcid,
    char *passwd,
    char *authzid);

LDAP_SASL_INTERACT_PROC lutil_sasl_interact;

int lutil_sasl_interact(
    LDAP * ld,
    unsigned flags,
    void *defaults,
    void *in);

void lutil_sasl_freedefs(
    void *defaults);

/*
 * SASL definitions for openldap support
 */

typedef struct lutil_sasl_defaults_s {
    char *mech;
    char *realm;
    char *authcid;
    char *passwd;
    char *authzid;
    char **resps;
    int nresps;
} lutilSASLdefaults;

void *
lutil_sasl_defaults(
    LDAP * ld,
    char *mech,
    char *realm,
    char *authcid,
    char *passwd,
    char *authzid)
{
    lutilSASLdefaults *defaults;

    defaults = (lutilSASLdefaults *) xmalloc(sizeof(lutilSASLdefaults));

    if (defaults == NULL)
        return NULL;

    defaults->mech = mech ? xstrdup(mech) : NULL;
    defaults->realm = realm ? xstrdup(realm) : NULL;
    defaults->authcid = authcid ? xstrdup(authcid) : NULL;
    defaults->passwd = passwd ? xstrdup(passwd) : NULL;
    defaults->authzid = authzid ? xstrdup(authzid) : NULL;

    if (defaults->mech == NULL) {
        ldap_get_option(ld, LDAP_OPT_X_SASL_MECH, &defaults->mech);
    }
    if (defaults->realm == NULL) {
        ldap_get_option(ld, LDAP_OPT_X_SASL_REALM, &defaults->realm);
    }
    if (defaults->authcid == NULL) {
        ldap_get_option(ld, LDAP_OPT_X_SASL_AUTHCID, &defaults->authcid);
    }
    if (defaults->authzid == NULL) {
        ldap_get_option(ld, LDAP_OPT_X_SASL_AUTHZID, &defaults->authzid);
    }
    defaults->resps = NULL;
    defaults->nresps = 0;

    return defaults;
}

static int
interaction(
    unsigned,
    sasl_interact_t * interact,
    lutilSASLdefaults * defaults)
{
    const char *dflt = interact->defresult;

    switch (interact->id) {
    case SASL_CB_GETREALM:
        if (defaults)
            dflt = defaults->realm;
        break;
    case SASL_CB_AUTHNAME:
        if (defaults)
            dflt = defaults->authcid;
        break;
    case SASL_CB_PASS:
        if (defaults)
            dflt = defaults->passwd;
        break;
    case SASL_CB_USER:
        if (defaults)
            dflt = defaults->authzid;
        break;
    case SASL_CB_NOECHOPROMPT:
        break;
    case SASL_CB_ECHOPROMPT:
        break;
    }

    if (dflt && !*dflt)
        dflt = NULL;

    /* input must be empty */
    interact->result = (dflt && *dflt) ? dflt : "";
    interact->len = (unsigned) strlen((const char *) interact->result);

    return LDAP_SUCCESS;
}

int
lutil_sasl_interact(
    LDAP * ld,
    unsigned flags,
    void *defaults,
    void *in)
{
    sasl_interact_t *interact = (sasl_interact_t *) in;

    if (ld == NULL)
        return LDAP_PARAM_ERROR;

    while (interact->id != SASL_CB_LIST_END) {
        int rc = interaction(flags, interact, (lutilSASLdefaults *) defaults);

        if (rc)
            return rc;
        ++interact;
    }

    return LDAP_SUCCESS;
}

void
lutil_sasl_freedefs(
    void *defaults)
{
    lutilSASLdefaults *defs = (lutilSASLdefaults *) defaults;

    xfree(defs->mech);
    xfree(defs->realm);
    xfree(defs->authcid);
    xfree(defs->passwd);
    xfree(defs->authzid);
    xfree(defs->resps);

    xfree(defs);
}

int
tool_sasl_bind(LDAP * ld, char *binddn, char *ssl)
{
    /*
     * unsigned sasl_flags = LDAP_SASL_AUTOMATIC;
     * unsigned sasl_flags = LDAP_SASL_QUIET;
     */
    /*
     * Avoid SASL messages
     */
#if HAVE_SUN_LDAP_SDK
    unsigned sasl_flags = LDAP_SASL_INTERACTIVE;
#else
    unsigned sasl_flags = LDAP_SASL_QUIET;
#endif
    char *sasl_realm = NULL;
    char *sasl_authc_id = NULL;
    char *sasl_authz_id = NULL;
    char *sasl_mech = (char *) "GSSAPI";
    /*
     * Force encryption
     */
    char *sasl_secprops;
    /*
     * char  *sasl_secprops = (char *)"maxssf=56";
     * char  *sasl_secprops = NULL;
     */
    struct berval passwd = {0, NULL};
    void *defaults;
    int rc = LDAP_SUCCESS;

    if (ssl)
        sasl_secprops = (char *) "maxssf=0";
    else
        sasl_secprops = (char *) "maxssf=56";
    /*      sasl_secprops = (char *)"maxssf=0"; */
    /*      sasl_secprops = (char *)"maxssf=56"; */

    if (sasl_secprops != NULL) {
        rc = ldap_set_option(ld, LDAP_OPT_X_SASL_SECPROPS,
                             (void *) sasl_secprops);
        if (rc != LDAP_SUCCESS) {
            error((char *) "%s| %s: ERROR: Could not set LDAP_OPT_X_SASL_SECPROPS: %s: %s\n", LogTime(), PROGRAM, sasl_secprops, ldap_err2string(rc));
            return rc;
        }
    }
    defaults = lutil_sasl_defaults(ld,
                                   sasl_mech,
                                   sasl_realm,
                                   sasl_authc_id,
                                   passwd.bv_val,
                                   sasl_authz_id);

    rc = ldap_sasl_interactive_bind_s(ld, binddn,
                                      sasl_mech, NULL, NULL,
                                      sasl_flags, lutil_sasl_interact, defaults);

    lutil_sasl_freedefs(defaults);
    if (rc != LDAP_SUCCESS) {
        error((char *) "%s| %s: ERROR: ldap_sasl_interactive_bind_s error: %s\n", LogTime(), PROGRAM, ldap_err2string(rc));
    }
    return rc;
}
#else
void dummy(void);
void
dummy(void)
{
    fprintf(stderr, "%s| %s: ERROR: Dummy function\n", LogTime(), PROGRAM);
}

#endif
#endif

