/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 1999-2022 The OpenLDAP Foundation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */

/*
 * LDAPv3 Extended Operation Request
 *	ExtendedRequest ::= [APPLICATION 23] SEQUENCE {
 *		requestName	 [0] LDAPOID,
 *		requestValue	 [1] OCTET STRING OPTIONAL
 *	}
 *
 * LDAPv3 Extended Operation Response
 *	ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
 *		COMPONENTS OF LDAPResult,
 *		responseName	 [10] LDAPOID OPTIONAL,
 *		response	 [11] OCTET STRING OPTIONAL
 *	}
 *
 */

#include "portable.h"

#include <stdio.h>

#include <ac/socket.h>
#include <ac/string.h>

#include "slap.h"
#include "lber_pvt.h"

static struct extop_list {
	struct extop_list *next;
	struct berval oid;
	slap_mask_t flags;
	SLAP_EXTOP_MAIN_FN *ext_main;
} *supp_ext_list = NULL;

static SLAP_EXTOP_MAIN_FN whoami_extop;

/* This list of built-in extops is for extops that are not part
 * of backends or in external modules.	Essentially, this is
 * just a way to get built-in extops onto the extop list without
 * having a separate init routine for each built-in extop.
 */
static struct {
	const struct berval *oid;
	slap_mask_t flags;
	SLAP_EXTOP_MAIN_FN *ext_main;
} builtin_extops[] = {
	{ &slap_EXOP_TXN_START, 0, txn_start_extop },
	{ &slap_EXOP_TXN_END, 0, txn_end_extop },
	{ &slap_EXOP_CANCEL, 0, cancel_extop },
	{ &slap_EXOP_WHOAMI, 0, whoami_extop },
	{ &slap_EXOP_MODIFY_PASSWD, SLAP_EXOP_WRITES, passwd_extop },
	{ NULL, 0, NULL }
};


static struct extop_list *find_extop(
	struct extop_list *list, struct berval *oid );

struct berval *
get_supported_extop (int index)
{
	struct extop_list *ext;

	/* linear scan is slow, but this way doesn't force a
	 * big change on root_dse.c, where this routine is used.
	 */
	for (ext = supp_ext_list; ext != NULL && --index >= 0; ext = ext->next) {
		; /* empty */
	}

	if (ext == NULL) return NULL;

	return &ext->oid;
}


int exop_root_dse_info( Entry *e )
{
	AttributeDescription *ad_supportedExtension
		= slap_schema.si_ad_supportedExtension;
	struct berval vals[2];
	struct extop_list *ext;

	vals[1].bv_val = NULL;
	vals[1].bv_len = 0;

	for (ext = supp_ext_list; ext != NULL; ext = ext->next) {
		if( ext->flags & SLAP_EXOP_HIDE ) continue;

		vals[0] = ext->oid;

		if( attr_merge( e, ad_supportedExtension, vals, NULL ) ) {
			return LDAP_OTHER;
		}
	}

	return LDAP_SUCCESS;
}

int
do_extended(
    Operation	*op,
    SlapReply	*rs
)
{
	struct berval reqdata = {0, NULL};
	ber_len_t len;

	Debug( LDAP_DEBUG_TRACE, "%s do_extended\n",
		op->o_log_prefix );

	if( op->o_protocol < LDAP_VERSION3 ) {
		Debug( LDAP_DEBUG_ANY, "%s do_extended: protocol version (%d) too low\n",
			op->o_log_prefix, op->o_protocol );
		send_ldap_discon( op, rs, LDAP_PROTOCOL_ERROR, "requires LDAPv3" );
		rs->sr_err = SLAPD_DISCONNECT;
		goto done;
	}

	if ( ber_scanf( op->o_ber, "{m" /*}*/, &op->ore_reqoid ) == LBER_ERROR ) {
		Debug( LDAP_DEBUG_ANY, "%s do_extended: ber_scanf failed\n",
			op->o_log_prefix );
		send_ldap_discon( op, rs, LDAP_PROTOCOL_ERROR, "decoding error" );
		rs->sr_err = SLAPD_DISCONNECT;
		goto done;
	}

	if( ber_peek_tag( op->o_ber, &len ) == LDAP_TAG_EXOP_REQ_VALUE ) {
		if( ber_scanf( op->o_ber, "m", &reqdata ) == LBER_ERROR ) {
			Debug( LDAP_DEBUG_ANY, "%s do_extended: ber_scanf failed\n",
				op->o_log_prefix );
			send_ldap_discon( op, rs, LDAP_PROTOCOL_ERROR, "decoding error" );
			rs->sr_err = SLAPD_DISCONNECT;
			goto done;
		}
	}

	if( get_ctrls( op, rs, 1 ) != LDAP_SUCCESS ) {
		Debug( LDAP_DEBUG_ANY, "%s do_extended: get_ctrls failed\n",
			op->o_log_prefix );
		return rs->sr_err;
	} 

	Debug( LDAP_DEBUG_STATS, "%s EXT oid=%s\n",
	    op->o_log_prefix, op->ore_reqoid.bv_val );

	/* check for controls inappropriate for all extended operations */
	if( get_manageDSAit( op ) == SLAP_CONTROL_CRITICAL ) {
		send_ldap_error( op, rs,
			LDAP_UNAVAILABLE_CRITICAL_EXTENSION,
			"manageDSAit control inappropriate" );
		goto done;
	}

	/* FIXME: temporary? */
	if ( reqdata.bv_val ) {
		op->ore_reqdata = &reqdata;
	}

	op->o_bd = frontendDB;
	rs->sr_err = frontendDB->be_extended( op, rs );

	if ( rs->sr_err == SLAPD_ASYNCOP ||
		rs->sr_err == LDAP_TXN_SPECIFY_OKAY ) {
		/* skip cleanup */
		return rs->sr_err;
	}

	/* clean up in case some overlay set them? */
	if ( !BER_BVISNULL( &op->o_req_ndn ) ) {
		if ( !BER_BVISNULL( &op->o_req_dn )
			&& op->o_req_ndn.bv_val != op->o_req_dn.bv_val )
		{
			op->o_tmpfree( op->o_req_dn.bv_val, op->o_tmpmemctx );
		}
		op->o_tmpfree( op->o_req_ndn.bv_val, op->o_tmpmemctx );
		BER_BVZERO( &op->o_req_dn );
		BER_BVZERO( &op->o_req_ndn );
	}

done:
	return rs->sr_err;
}

int
fe_extended( Operation *op, SlapReply *rs )
{
	struct extop_list	*ext = NULL;
	struct berval		reqdata = BER_BVNULL;

	if (op->ore_reqdata) {
		reqdata = *op->ore_reqdata;
	}

	ext = find_extop(supp_ext_list, &op->ore_reqoid );
	if ( ext == NULL ) {
		Debug( LDAP_DEBUG_ANY, "%s do_extended: unsupported operation \"%s\"\n",
			op->o_log_prefix, op->ore_reqoid.bv_val );
		send_ldap_error( op, rs, LDAP_PROTOCOL_ERROR,
			"unsupported extended operation" );
		goto done;
	}

	op->ore_flags = ext->flags;

	Debug( LDAP_DEBUG_ARGS, "do_extended: oid=%s\n",
		op->ore_reqoid.bv_val );

	{ /* start of OpenLDAP extended operation */
		BackendDB	*bd = op->o_bd;

		rs->sr_err = (ext->ext_main)( op, rs );

		if( rs->sr_err != SLAPD_ABANDON && rs->sr_err != SLAPD_ASYNCOP &&
			rs->sr_err != SLAPD_NO_REPLY ) {
			if ( rs->sr_err == LDAP_REFERRAL && rs->sr_ref == NULL ) {
				rs->sr_ref = referral_rewrite( default_referral,
					NULL, NULL, LDAP_SCOPE_DEFAULT );
				if ( !rs->sr_ref ) rs->sr_ref = default_referral;
				if ( !rs->sr_ref ) {
					rs->sr_err = LDAP_UNWILLING_TO_PERFORM;
					rs->sr_text = "referral missing";
				}
			}

			if ( op->o_bd == NULL )
				op->o_bd = bd;
			send_ldap_extended( op, rs );

			if ( rs->sr_ref != default_referral ) {
				ber_bvarray_free( rs->sr_ref );
				rs->sr_ref = NULL;
			}
		}

		if ( rs->sr_rspoid != NULL ) {
			free( (char *)rs->sr_rspoid );
			rs->sr_rspoid = NULL;
		}

		if ( rs->sr_rspdata != NULL ) {
			ber_bvfree( rs->sr_rspdata );
			rs->sr_rspdata = NULL;
		}
	} /* end of OpenLDAP extended operation */

done:;
	return rs->sr_err;
}

int
load_extop2(
	const struct berval *ext_oid,
	slap_mask_t ext_flags,
	SLAP_EXTOP_MAIN_FN *ext_main,
	unsigned flags )
{
	struct berval		oidm = BER_BVNULL;
	struct extop_list	*ext;
	int			insertme = 0;

	if ( !ext_main ) {
		return -1; 
	}

	if ( ext_oid == NULL || BER_BVISNULL( ext_oid ) ||
		BER_BVISEMPTY( ext_oid ) )
	{
		return -1; 
	}

	if ( numericoidValidate( NULL, (struct berval *)ext_oid ) !=
		LDAP_SUCCESS )
	{
		oidm.bv_val = oidm_find( ext_oid->bv_val );
		if ( oidm.bv_val == NULL ) {
			return -1;
		}
		oidm.bv_len = strlen( oidm.bv_val );
		ext_oid = &oidm;
	}

	for ( ext = supp_ext_list; ext; ext = ext->next ) {
		if ( bvmatch( ext_oid, &ext->oid ) ) {
			if ( flags == 1 ) {
				break;
			}
			return -1;
		}
	}

	if ( flags == 0 || ext == NULL ) {
		ext = ch_calloc( 1, sizeof(struct extop_list) + ext_oid->bv_len + 1 );
		if ( ext == NULL ) {
			return(-1);
		}

		ext->oid.bv_val = (char *)(ext + 1);
		AC_MEMCPY( ext->oid.bv_val, ext_oid->bv_val, ext_oid->bv_len );
		ext->oid.bv_len = ext_oid->bv_len;
		ext->oid.bv_val[ext->oid.bv_len] = '\0';

		insertme = 1;
	}

	ext->flags = ext_flags;
	ext->ext_main = ext_main;

	if ( insertme ) {
		ext->next = supp_ext_list;
		supp_ext_list = ext;
	}

	return(0);
}

int
unload_extop(
	const struct berval *ext_oid,
	SLAP_EXTOP_MAIN_FN *ext_main,
	unsigned flags )
{
	struct berval		oidm = BER_BVNULL;
	struct extop_list	*ext, **extp;

	/* oid must be given */
	if ( ext_oid == NULL || BER_BVISNULL( ext_oid ) ||
		BER_BVISEMPTY( ext_oid ) )
	{
		return -1; 
	}

	/* if it's not an oid, check if it's a macto */
	if ( numericoidValidate( NULL, (struct berval *)ext_oid ) !=
		LDAP_SUCCESS )
	{
		oidm.bv_val = oidm_find( ext_oid->bv_val );
		if ( oidm.bv_val == NULL ) {
			return -1;
		}
		oidm.bv_len = strlen( oidm.bv_val );
		ext_oid = &oidm;
	}

	/* lookup the oid */
	for ( extp = &supp_ext_list; *extp; extp = &(*extp)->next ) {
		if ( bvmatch( ext_oid, &(*extp)->oid ) ) {
			/* if ext_main is given, only remove if it matches */
			if ( ext_main != NULL && (*extp)->ext_main != ext_main ) {
				return -1;
			}
			break;
		}
	}

	if ( *extp == NULL ) {
		return -1;
	}

	ext = *extp;
	*extp = (*extp)->next;

	ch_free( ext );

	return 0;
}

int
extops_init (void)
{
	int i;

	for ( i = 0; builtin_extops[i].oid != NULL; i++ ) {
		load_extop( (struct berval *)builtin_extops[i].oid,
			builtin_extops[i].flags,
			builtin_extops[i].ext_main );
	}

	return(0);
}

int
extops_kill (void)
{
	struct extop_list *ext;

	/* we allocated the memory, so we have to free it, too. */
	while ((ext = supp_ext_list) != NULL) {
		supp_ext_list = ext->next;
		ch_free(ext);
	}
	return(0);
}

static struct extop_list *
find_extop( struct extop_list *list, struct berval *oid )
{
	struct extop_list *ext;

	for (ext = list; ext; ext = ext->next) {
		if (bvmatch(&ext->oid, oid))
			return(ext);
	}
	return(NULL);
}


const struct berval slap_EXOP_WHOAMI = BER_BVC(LDAP_EXOP_WHO_AM_I);

static int
whoami_extop (
	Operation *op,
	SlapReply *rs )
{
	struct berval *bv;

	if ( op->ore_reqdata != NULL ) {
		/* no request data should be provided */
		rs->sr_text = "no request data expected";
		return LDAP_PROTOCOL_ERROR;
	}

	Debug( LDAP_DEBUG_STATS, "%s WHOAMI\n",
	    op->o_log_prefix );

	op->o_bd = op->o_conn->c_authz_backend;
	if( backend_check_restrictions( op, rs,
		(struct berval *)&slap_EXOP_WHOAMI ) != LDAP_SUCCESS )
	{
		return rs->sr_err;
	}

	bv = (struct berval *) ch_malloc( sizeof(struct berval) );
	if( op->o_dn.bv_len ) {
		bv->bv_len = op->o_dn.bv_len + STRLENOF( "dn:" );
		bv->bv_val = ch_malloc( bv->bv_len + 1 );
		AC_MEMCPY( bv->bv_val, "dn:", STRLENOF( "dn:" ) );
		AC_MEMCPY( &bv->bv_val[STRLENOF( "dn:" )], op->o_dn.bv_val,
			op->o_dn.bv_len );
		bv->bv_val[bv->bv_len] = '\0';

	} else {
		bv->bv_len = 0;
		bv->bv_val = NULL;
	}

	rs->sr_rspdata = bv;
	return LDAP_SUCCESS;
}