/* 
   Unix SMB2 implementation.
   
   Copyright (C) Andrew Bartlett	2001-2005
   Copyright (C) Stefan Metzmacher	2005
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "auth/credentials/credentials.h"
#include "auth/auth.h"
#include "auth/gensec/gensec.h"
#include "libcli/raw/libcliraw.h"
#include "libcli/raw/raw_proto.h"
#include "libcli/smb2/smb2.h"
#include "libcli/smb2/smb2_calls.h"
#include "smb_server/smb_server.h"
#include "smb_server/smb2/smb2_server.h"
#include "smbd/service_stream.h"
#include "param/param.h"

static NTSTATUS smb2srv_negprot_secblob(struct smb2srv_request *req, DATA_BLOB *_blob)
{
	struct gensec_security *gensec_security;
	DATA_BLOB null_data_blob = data_blob(NULL, 0);
	DATA_BLOB blob;
	NTSTATUS nt_status;
	struct cli_credentials *server_credentials;

	server_credentials = cli_credentials_init(req);
	if (!server_credentials) {
		smbsrv_terminate_connection(req->smb_conn, "Failed to init server credentials\n");
		return NT_STATUS_NO_MEMORY;
	}

	cli_credentials_set_conf(server_credentials, req->smb_conn->lp_ctx);
	nt_status = cli_credentials_set_machine_account(server_credentials, req->smb_conn->lp_ctx);
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(nt_status)));
		talloc_free(server_credentials);
		server_credentials = NULL;
	}

	req->smb_conn->negotiate.server_credentials = talloc_steal(req->smb_conn, server_credentials);

	nt_status = samba_server_gensec_start(req,
					      req->smb_conn->connection->event.ctx,
					      req->smb_conn->connection->msg_ctx,
					      req->smb_conn->lp_ctx,
					      server_credentials,
					      "cifs",
					      &gensec_security);
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0, ("Failed to start GENSEC: %s\n", nt_errstr(nt_status)));
		smbsrv_terminate_connection(req->smb_conn, "Failed to start GENSEC\n");
		return nt_status;
	}

	gensec_set_target_service(gensec_security, "cifs");

	gensec_set_credentials(gensec_security, server_credentials);

	nt_status = gensec_start_mech_by_oid(gensec_security, GENSEC_OID_SPNEGO);
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0, ("Failed to start SPNEGO: %s\n", nt_errstr(nt_status)));
		smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO\n");
		return nt_status;
	}

	nt_status = gensec_update(gensec_security, req, req->smb_conn->connection->event.ctx, null_data_blob, &blob);
	if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
		DEBUG(0, ("Failed to get SPNEGO to give us the first token: %s\n", nt_errstr(nt_status)));
		smbsrv_terminate_connection(req->smb_conn, "Failed to start SPNEGO - no first token\n");
		return nt_status;
	}

	*_blob = blob;
	return NT_STATUS_OK;
}

static NTSTATUS smb2srv_negprot_backend(struct smb2srv_request *req, struct smb2_negprot *io)
{
	NTSTATUS status;
	struct timeval current_time;
	struct timeval boot_time;
	uint16_t i;
	uint16_t dialect = 0;
	enum smb_signing_setting signing_setting;
	struct loadparm_context *lp_ctx = req->smb_conn->lp_ctx;

	/* we only do one dialect for now */
	if (io->in.dialect_count < 1) {
		return NT_STATUS_NOT_SUPPORTED;
	}
	for (i=0; i < io->in.dialect_count; i++) {
		dialect = io->in.dialects[i];
		if (dialect == SMB2_DIALECT_REVISION_202) {
			break;
		}
	}
	if (dialect != SMB2_DIALECT_REVISION_202) {
		DEBUG(0,("Got unexpected SMB2 dialect %u\n", dialect));
		return NT_STATUS_NOT_SUPPORTED;
	}

	req->smb_conn->negotiate.protocol = PROTOCOL_SMB2_02;

	current_time = timeval_current(); /* TODO: handle timezone?! */
	boot_time = timeval_current(); /* TODO: fix me */

	ZERO_STRUCT(io->out);

	signing_setting = lpcfg_server_signing(lp_ctx);
	if (signing_setting == SMB_SIGNING_DEFAULT) {
		/*
		 * If we are a domain controller, SMB signing is
		 * really important, as it can prevent a number of
		 * attacks on communications between us and the
		 * clients
		 *
		 * However, it really sucks (no sendfile, CPU
		 * overhead) performance-wise when used on a
		 * file server, so disable it by default
		 * on non-DCs
		 */

		if (lpcfg_server_role(lp_ctx) >= ROLE_ACTIVE_DIRECTORY_DC) {
			signing_setting = SMB_SIGNING_REQUIRED;
		} else {
			signing_setting = SMB_SIGNING_OFF;
		}
	}

	switch (signing_setting) {
	case SMB_SIGNING_DEFAULT:
		smb_panic(__location__);
		break;
	case SMB_SIGNING_OFF:
		io->out.security_mode = 0;
		break;
	case SMB_SIGNING_IF_REQUIRED:
		io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED;
		break;
	case SMB_SIGNING_REQUIRED:
		io->out.security_mode = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED;
		/* force signing on immediately */
		req->smb_conn->smb2_signing_required = true;
		break;
	}
	io->out.dialect_revision   = dialect;
	io->out.capabilities       = 0;
	io->out.max_transact_size  = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
						   "smb2", "max transaction size", 0x10000);
	io->out.max_read_size      = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
						   "smb2", "max read size", 0x10000);
	io->out.max_write_size     = lpcfg_parm_ulong(req->smb_conn->lp_ctx, NULL,
						   "smb2", "max write size", 0x10000);
	io->out.system_time	   = timeval_to_nttime(&current_time);
	io->out.server_start_time  = timeval_to_nttime(&boot_time);
	io->out.reserved2          = 0;
	status = smb2srv_negprot_secblob(req, &io->out.secblob);
	NT_STATUS_NOT_OK_RETURN(status);

	return NT_STATUS_OK;
}

static void smb2srv_negprot_send(struct smb2srv_request *req, struct smb2_negprot *io)
{
	NTSTATUS status;

	if (NT_STATUS_IS_ERR(req->status)) {
		smb2srv_send_error(req, req->status); /* TODO: is this correct? */
		return;
	}

	status = smb2srv_setup_reply(req, 0x40, true, io->out.secblob.length);
	if (!NT_STATUS_IS_OK(status)) {
		smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
		talloc_free(req);
		return;
	}

	SSVAL(req->out.body, 0x02, io->out.security_mode);
	SIVAL(req->out.body, 0x04, io->out.dialect_revision);
	SIVAL(req->out.body, 0x06, io->out.reserved);
	status = smbcli_push_guid(req->out.body, 0x08, &io->out.server_guid);
	if (!NT_STATUS_IS_OK(status)) {
		smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
		talloc_free(req);
		return;
	}
	SIVAL(req->out.body, 0x18, io->out.capabilities);
	SIVAL(req->out.body, 0x1C, io->out.max_transact_size);
	SIVAL(req->out.body, 0x20, io->out.max_read_size);
	SIVAL(req->out.body, 0x24, io->out.max_write_size);
	push_nttime(req->out.body, 0x28, io->out.system_time);
	push_nttime(req->out.body, 0x30, io->out.server_start_time);
	SIVAL(req->out.body, 0x3C, io->out.reserved2);
	status = smb2_push_o16s16_blob(&req->out, 0x38, io->out.secblob);
	if (!NT_STATUS_IS_OK(status)) {
		smbsrv_terminate_connection(req->smb_conn, nt_errstr(status));
		talloc_free(req);
		return;
	}

	smb2srv_send_reply(req);
}

void smb2srv_negprot_recv(struct smb2srv_request *req)
{
	struct smb2_negprot *io;
	int i;

	if (req->in.body_size < 0x26) {
		smbsrv_terminate_connection(req->smb_conn, "Bad body size in SMB2 negprot");
		return;
	}

	io = talloc(req, struct smb2_negprot);
	if (!io) {
		smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
		talloc_free(req);
		return;
	}

	io->in.dialect_count = SVAL(req->in.body, 0x02);
	io->in.security_mode = SVAL(req->in.body, 0x04);
	io->in.reserved      = SVAL(req->in.body, 0x06);
	io->in.capabilities  = IVAL(req->in.body, 0x08);
	req->status = smbcli_pull_guid(req->in.body, 0xC, &io->in.client_guid);
	if (!NT_STATUS_IS_OK(req->status)) {
		smbsrv_terminate_connection(req->smb_conn, "Bad GUID in SMB2 negprot");
		talloc_free(req);
		return;
	}
	io->in.start_time = smbcli_pull_nttime(req->in.body, 0x1C);

	io->in.dialects = talloc_array(req, uint16_t, io->in.dialect_count);
	if (io->in.dialects == NULL) {
		smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
		talloc_free(req);
		return;
	}
	for (i=0;i<io->in.dialect_count;i++) {
		io->in.dialects[i] = SVAL(req->in.body, 0x24+i*2);
	}

	req->status = smb2srv_negprot_backend(req, io);

	if (req->control_flags & SMB2SRV_REQ_CTRL_FLAG_NOT_REPLY) {
		talloc_free(req);
		return;
	}
	smb2srv_negprot_send(req, io);
}

/*
 * reply to a SMB negprot request with dialect "SMB 2.002"
 */
void smb2srv_reply_smb_negprot(struct smbsrv_request *smb_req)
{
	struct smb2srv_request *req;
	uint32_t body_fixed_size = 0x26;

	req = talloc_zero(smb_req->smb_conn, struct smb2srv_request);
	if (!req) goto nomem;
	req->smb_conn		= smb_req->smb_conn;
	req->request_time	= smb_req->request_time;
	talloc_steal(req, smb_req);

	req->in.size      = NBT_HDR_SIZE+SMB2_HDR_BODY+body_fixed_size;
	req->in.allocated = req->in.size;
	req->in.buffer    = talloc_array(req, uint8_t, req->in.allocated);
	if (!req->in.buffer) goto nomem;
	req->in.hdr       = req->in.buffer + NBT_HDR_SIZE;
	req->in.body      = req->in.hdr + SMB2_HDR_BODY;
	req->in.body_size = body_fixed_size;
	req->in.dynamic   = NULL;

	smb2srv_setup_bufinfo(req);

	SIVAL(req->in.hdr, 0,				SMB2_MAGIC);
	SSVAL(req->in.hdr, SMB2_HDR_LENGTH,		SMB2_HDR_BODY);
	SSVAL(req->in.hdr, SMB2_HDR_EPOCH,		0);
	SIVAL(req->in.hdr, SMB2_HDR_STATUS,		0);
	SSVAL(req->in.hdr, SMB2_HDR_OPCODE,		SMB2_OP_NEGPROT);
	SSVAL(req->in.hdr, SMB2_HDR_CREDIT,		0);
	SIVAL(req->in.hdr, SMB2_HDR_FLAGS,		0);
	SIVAL(req->in.hdr, SMB2_HDR_NEXT_COMMAND,	0);
	SBVAL(req->in.hdr, SMB2_HDR_MESSAGE_ID,		0);
	SIVAL(req->in.hdr, SMB2_HDR_PID,		0);
	SIVAL(req->in.hdr, SMB2_HDR_TID,		0);
	SBVAL(req->in.hdr, SMB2_HDR_SESSION_ID,		0);
	memset(req->in.hdr+SMB2_HDR_SIGNATURE, 0, 16);

	/* this seems to be a bug, they use 0x24 but the length is 0x26 */
	SSVAL(req->in.body, 0x00, 0x24);

	SSVAL(req->in.body, 0x02, 1);
	memset(req->in.body+0x04, 0, 32);
	SSVAL(req->in.body, 0x24, SMB2_DIALECT_REVISION_202);

	smb2srv_negprot_recv(req);
	return;
nomem:
	smbsrv_terminate_connection(smb_req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
	talloc_free(req);
	return;
}