samba-mirror/source3/smbd/smb1_negprot.c

/* 
   Unix SMB/CIFS implementation.
   negprot reply code
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Volker Lendecke 2007

   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 "smbd/smbd.h"
#include "smbd/globals.h"
#include "serverid.h"
#include "auth.h"
#include "messages.h"
#include "smbprofile.h"
#include "auth/gensec/gensec.h"
#include "../libcli/smb/smb_signing.h"
#include "lib/util/string_wrappers.h"
#include "source3/lib/substitute.h"

/*
 * MS-CIFS, 2.2.4.52.2 SMB_COM_NEGOTIATE Response:
 * If the server does not support any of the listed dialects, it MUST return a
 * DialectIndex of 0XFFFF
 */
#define NO_PROTOCOL_CHOSEN	0xffff

static void get_challenge(struct smbXsrv_connection *xconn, uint8_t buff[8])
{
	NTSTATUS nt_status;

	/* We might be called more than once, multiple negprots are
	 * permitted */
	if (xconn->smb1.negprot.auth_context) {
		DEBUG(3, ("get challenge: is this a secondary negprot? "
			  "sconn->negprot.auth_context is non-NULL!\n"));
		TALLOC_FREE(xconn->smb1.negprot.auth_context);
	}

	DEBUG(10, ("get challenge: creating negprot_global_auth_context\n"));
	nt_status = make_auth4_context(
		xconn, &xconn->smb1.negprot.auth_context);
	if (!NT_STATUS_IS_OK(nt_status)) {
		DEBUG(0, ("make_auth_context_subsystem returned %s\n",
			  nt_errstr(nt_status)));
		smb_panic("cannot make_negprot_global_auth_context!");
	}
	DEBUG(10, ("get challenge: getting challenge\n"));
	xconn->smb1.negprot.auth_context->get_ntlm_challenge(
		xconn->smb1.negprot.auth_context, buff);
}

/****************************************************************************
 Reply for the lanman 1.0 protocol.
****************************************************************************/

static NTSTATUS reply_lanman1(struct smb_request *req, uint16_t choice)
{
	int secword=0;
	time_t t = time(NULL);
	struct smbXsrv_connection *xconn = req->xconn;
	uint16_t raw;
	NTSTATUS status;

	if (lp_async_smb_echo_handler()) {
		raw = 0;
	} else {
		raw = (lp_read_raw()?1:0) | (lp_write_raw()?2:0);
	}

	xconn->smb1.negprot.encrypted_passwords = lp_encrypt_passwords();

	secword |= NEGOTIATE_SECURITY_USER_LEVEL;
	if (xconn->smb1.negprot.encrypted_passwords) {
		secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
	}

	reply_smb1_outbuf(req, 13, xconn->smb1.negprot.encrypted_passwords?8:0);

	SSVAL(req->outbuf,smb_vwv0,choice);
	SSVAL(req->outbuf,smb_vwv1,secword);
	/* Create a token value and add it to the outgoing packet. */
	if (xconn->smb1.negprot.encrypted_passwords) {
		get_challenge(xconn, (uint8_t *)smb_buf(req->outbuf));
		SSVAL(req->outbuf,smb_vwv11, 8);
	}

	status = smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN1);
	if (!NT_STATUS_IS_OK(status)) {
		reply_nterror(req, status);
		return status;
	}

	/* Reply, SMBlockread, SMBwritelock supported. */
	SCVAL(req->outbuf,smb_flg, FLAG_REPLY|FLAG_SUPPORT_LOCKREAD);
	SSVAL(req->outbuf,smb_vwv2, xconn->smb1.negprot.max_recv);
	SSVAL(req->outbuf,smb_vwv3, lp_max_mux()); /* maxmux */
	SSVAL(req->outbuf,smb_vwv4, 1);
	SSVAL(req->outbuf,smb_vwv5, raw); /* tell redirector we support
		readbraw writebraw (possibly) */
	SIVAL(req->outbuf,smb_vwv6, getpid());
	SSVAL(req->outbuf,smb_vwv10, set_server_zone_offset(t)/60);

	srv_put_dos_date((char *)req->outbuf,smb_vwv8,t);

	return NT_STATUS_OK;
}

/****************************************************************************
 Reply for the lanman 2.0 protocol.
****************************************************************************/

static NTSTATUS reply_lanman2(struct smb_request *req, uint16_t choice)
{
	int secword=0;
	time_t t = time(NULL);
	struct smbXsrv_connection *xconn = req->xconn;
	uint16_t raw;
	NTSTATUS status;

	if (lp_async_smb_echo_handler()) {
		raw = 0;
	} else {
		raw = (lp_read_raw()?1:0) | (lp_write_raw()?2:0);
	}

	xconn->smb1.negprot.encrypted_passwords = lp_encrypt_passwords();

	secword |= NEGOTIATE_SECURITY_USER_LEVEL;
	if (xconn->smb1.negprot.encrypted_passwords) {
		secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
	}

	reply_smb1_outbuf(req, 13, xconn->smb1.negprot.encrypted_passwords?8:0);

	SSVAL(req->outbuf,smb_vwv0, choice);
	SSVAL(req->outbuf,smb_vwv1, secword);
	SIVAL(req->outbuf,smb_vwv6, getpid());

	/* Create a token value and add it to the outgoing packet. */
	if (xconn->smb1.negprot.encrypted_passwords) {
		get_challenge(xconn, (uint8_t *)smb_buf(req->outbuf));
		SSVAL(req->outbuf,smb_vwv11, 8);
	}

	status = smbXsrv_connection_init_tables(xconn, PROTOCOL_LANMAN2);
	if (!NT_STATUS_IS_OK(status)) {
		reply_nterror(req, status);
		return status;
	}

	/* Reply, SMBlockread, SMBwritelock supported. */
	SCVAL(req->outbuf,smb_flg,FLAG_REPLY|FLAG_SUPPORT_LOCKREAD);
	SSVAL(req->outbuf,smb_vwv2,xconn->smb1.negprot.max_recv);
	SSVAL(req->outbuf,smb_vwv3,lp_max_mux());
	SSVAL(req->outbuf,smb_vwv4,1);
	SSVAL(req->outbuf,smb_vwv5,raw); /* readbraw and/or writebraw */
	SSVAL(req->outbuf,smb_vwv10, set_server_zone_offset(t)/60);
	srv_put_dos_date((char *)req->outbuf,smb_vwv8,t);
	return NT_STATUS_OK;
}

/****************************************************************************
 Reply for the nt protocol.
****************************************************************************/

static NTSTATUS reply_nt1(struct smb_request *req, uint16_t choice)
{
	/* dual names + lock_and_read + nt SMBs + remote API calls */
	int capabilities = CAP_NT_FIND|CAP_LOCK_AND_READ|
		CAP_LEVEL_II_OPLOCKS;

	int secword=0;
	bool negotiate_spnego = False;
	struct timespec ts;
	ssize_t ret;
	struct smbXsrv_connection *xconn = req->xconn;
	bool signing_desired = false;
	bool signing_required = false;
	NTSTATUS status;

	xconn->smb1.negprot.encrypted_passwords = lp_encrypt_passwords();

	/* Check the flags field to see if this is Vista.
	   WinXP sets it and Vista does not. But we have to 
	   distinguish from NT which doesn't set it either. */

	if ( (req->flags2 & FLAGS2_EXTENDED_SECURITY) &&
		((req->flags2 & FLAGS2_SMB_SECURITY_SIGNATURES_REQUIRED) == 0) )
	{
		if ((get_remote_arch() != RA_SAMBA) &&
				(get_remote_arch() != RA_CIFSFS)) {
			set_remote_arch( RA_VISTA );
		}
	}

	reply_smb1_outbuf(req,17,0);

	/* do spnego in user level security if the client
	   supports it and we can do encrypted passwords */

	if (xconn->smb1.negprot.encrypted_passwords &&
	    (req->flags2 & FLAGS2_EXTENDED_SECURITY)) {
		negotiate_spnego = True;
		capabilities |= CAP_EXTENDED_SECURITY;
		add_to_common_flags2(FLAGS2_EXTENDED_SECURITY);
		/* Ensure FLAGS2_EXTENDED_SECURITY gets set in this reply
		   (already partially constructed. */
		SSVAL(req->outbuf, smb_flg2,
		      req->flags2 | FLAGS2_EXTENDED_SECURITY);
	}

	capabilities |= CAP_NT_SMBS|CAP_RPC_REMOTE_APIS;

	if (lp_unicode()) {
		capabilities |= CAP_UNICODE;
	}

	if (lp_smb1_unix_extensions()) {
		capabilities |= CAP_UNIX;
	}

	if (lp_large_readwrite())
		capabilities |= CAP_LARGE_READX|CAP_LARGE_WRITEX|CAP_W2K_SMBS;

	capabilities |= CAP_LARGE_FILES;

	if (!lp_async_smb_echo_handler() && lp_read_raw() && lp_write_raw())
		capabilities |= CAP_RAW_MODE;

	if (lp_nt_status_support())
		capabilities |= CAP_STATUS32;

	if (lp_host_msdfs())
		capabilities |= CAP_DFS;

	secword |= NEGOTIATE_SECURITY_USER_LEVEL;
	if (xconn->smb1.negprot.encrypted_passwords) {
		secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
	}

	signing_desired = smb1_signing_is_desired(xconn->smb1.signing_state);
	signing_required = smb1_signing_is_mandatory(xconn->smb1.signing_state);

	if (signing_desired) {
		secword |= NEGOTIATE_SECURITY_SIGNATURES_ENABLED;
		/* No raw mode with smb signing. */
		capabilities &= ~CAP_RAW_MODE;
		if (signing_required) {
			secword |=NEGOTIATE_SECURITY_SIGNATURES_REQUIRED;
		}
	}

	SSVAL(req->outbuf,smb_vwv0,choice);
	SCVAL(req->outbuf,smb_vwv1,secword);

	status = smbXsrv_connection_init_tables(xconn, PROTOCOL_NT1);
	if (!NT_STATUS_IS_OK(status)) {
		reply_nterror(req, status);
		return status;
	}

	SSVAL(req->outbuf,smb_vwv1+1, lp_max_mux()); /* maxmpx */
	SSVAL(req->outbuf,smb_vwv2+1, 1); /* num vcs */
	SIVAL(req->outbuf,smb_vwv3+1,
	      xconn->smb1.negprot.max_recv); /* max buffer. LOTS! */
	SIVAL(req->outbuf,smb_vwv5+1, 0x10000); /* raw size. full 64k */
	SIVAL(req->outbuf,smb_vwv7+1, getpid()); /* session key */
	SIVAL(req->outbuf,smb_vwv9+1, capabilities); /* capabilities */
	clock_gettime(CLOCK_REALTIME,&ts);
	put_long_date_full_timespec(TIMESTAMP_SET_NT_OR_BETTER,(char *)req->outbuf+smb_vwv11+1,&ts);
	SSVALS(req->outbuf,smb_vwv15+1,set_server_zone_offset(ts.tv_sec)/60);

	if (!negotiate_spnego) {
		/* Create a token value and add it to the outgoing packet. */
		if (xconn->smb1.negprot.encrypted_passwords) {
			uint8_t chal[8];
			/* note that we do not send a challenge at all if
			   we are using plaintext */
			get_challenge(xconn, chal);
			ret = message_push_blob(
				&req->outbuf, data_blob_const(chal, sizeof(chal)));
			if (ret == -1) {
				DEBUG(0, ("Could not push challenge\n"));
				reply_nterror(req, NT_STATUS_NO_MEMORY);
				return NT_STATUS_NO_MEMORY;
			}
			SCVAL(req->outbuf, smb_vwv16+1, ret);
		}
		ret = message_push_string(&req->outbuf, lp_workgroup(),
					  STR_UNICODE|STR_TERMINATE
					  |STR_NOALIGN);
		if (ret == -1) {
			DEBUG(0, ("Could not push workgroup string\n"));
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			return NT_STATUS_NO_MEMORY;
		}
		ret = message_push_string(&req->outbuf, lp_netbios_name(),
					  STR_UNICODE|STR_TERMINATE
					  |STR_NOALIGN);
		if (ret == -1) {
			DEBUG(0, ("Could not push netbios name string\n"));
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			return NT_STATUS_NO_MEMORY;
		}
		DEBUG(3,("not using SPNEGO\n"));
	} else {
		DATA_BLOB spnego_blob = negprot_spnego(req, xconn);

		if (spnego_blob.data == NULL) {
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			return NT_STATUS_NO_MEMORY;
		}

		ret = message_push_blob(&req->outbuf, spnego_blob);
		if (ret == -1) {
			DEBUG(0, ("Could not push spnego blob\n"));
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			return NT_STATUS_NO_MEMORY;
		}
		data_blob_free(&spnego_blob);

		SCVAL(req->outbuf,smb_vwv16+1, 0);
		DEBUG(3,("using SPNEGO\n"));
	}

	return NT_STATUS_OK;
}

/* these are the protocol lists used for auto architecture detection:

WinNT 3.51:
protocol [PC NETWORK PROGRAM 1.0]
protocol [XENIX CORE]
protocol [MICROSOFT NETWORKS 1.03]
protocol [LANMAN1.0]
protocol [Windows for Workgroups 3.1a]
protocol [LM1.2X002]
protocol [LANMAN2.1]
protocol [NT LM 0.12]

Win95:
protocol [PC NETWORK PROGRAM 1.0]
protocol [XENIX CORE]
protocol [MICROSOFT NETWORKS 1.03]
protocol [LANMAN1.0]
protocol [Windows for Workgroups 3.1a]
protocol [LM1.2X002]
protocol [LANMAN2.1]
protocol [NT LM 0.12]

Win2K:
protocol [PC NETWORK PROGRAM 1.0]
protocol [LANMAN1.0]
protocol [Windows for Workgroups 3.1a]
protocol [LM1.2X002]
protocol [LANMAN2.1]
protocol [NT LM 0.12]

Vista:
protocol [PC NETWORK PROGRAM 1.0]
protocol [LANMAN1.0]
protocol [Windows for Workgroups 3.1a]
protocol [LM1.2X002]
protocol [LANMAN2.1]
protocol [NT LM 0.12]
protocol [SMB 2.001]

OS/2:
protocol [PC NETWORK PROGRAM 1.0]
protocol [XENIX CORE]
protocol [LANMAN1.0]
protocol [LM1.2X002]
protocol [LANMAN2.1]

OSX:
protocol [NT LM 0.12]
protocol [SMB 2.002]
protocol [SMB 2.???]
*/

/*
  * Modified to recognize the architecture of the remote machine better.
  *
  * This appears to be the matrix of which protocol is used by which
  * product.
       Protocol                       WfWg Win95 WinNT Win2K OS/2 Vista OSX
       PC NETWORK PROGRAM 1.0          1     1     1     1     1    1
       XENIX CORE                                  2           2
       MICROSOFT NETWORKS 3.0          2     2
       DOS LM1.2X002                   3     3
       MICROSOFT NETWORKS 1.03                     3
       DOS LANMAN2.1                   4     4
       LANMAN1.0                                   4     2     3    2
       Windows for Workgroups 3.1a     5     5     5     3          3
       LM1.2X002                                   6     4     4    4
       LANMAN2.1                                   7     5     5    5
       NT LM 0.12                            6     8     6     6    6    1
       SMB 2.001                                                    7
       SMB 2.002                                                         2
       SMB 2.???                                                         3
  *
  *  tim@fsg.com 09/29/95
  *  Win2K added by matty 17/7/99
  */

#define PROT_PC_NETWORK_PROGRAM_1_0		0x0001
#define PROT_XENIX_CORE				0x0002
#define PROT_MICROSOFT_NETWORKS_3_0		0x0004
#define PROT_DOS_LM1_2X002			0x0008
#define PROT_MICROSOFT_NETWORKS_1_03		0x0010
#define PROT_DOS_LANMAN2_1			0x0020
#define PROT_LANMAN1_0				0x0040
#define PROT_WFWG				0x0080
#define PROT_LM1_2X002				0x0100
#define PROT_LANMAN2_1				0x0200
#define PROT_NT_LM_0_12				0x0400
#define PROT_SMB_2_001				0x0800
#define PROT_SMB_2_002				0x1000
#define PROT_SMB_2_FF				0x2000
#define PROT_SAMBA				0x4000
#define PROT_POSIX_2				0x8000

#define ARCH_WFWG     ( PROT_PC_NETWORK_PROGRAM_1_0 | PROT_MICROSOFT_NETWORKS_3_0 | \
			PROT_DOS_LM1_2X002 | PROT_DOS_LANMAN2_1 | PROT_WFWG )
#define ARCH_WIN95    ( ARCH_WFWG | PROT_NT_LM_0_12 )
#define ARCH_WINNT    ( PROT_PC_NETWORK_PROGRAM_1_0 | PROT_XENIX_CORE | \
			PROT_MICROSOFT_NETWORKS_1_03 | PROT_LANMAN1_0 | PROT_WFWG | \
			PROT_LM1_2X002 | PROT_LANMAN2_1 | PROT_NT_LM_0_12 )
#define ARCH_WIN2K    ( ARCH_WINNT & ~(PROT_XENIX_CORE | PROT_MICROSOFT_NETWORKS_1_03) )
#define ARCH_OS2      ( ARCH_WINNT & ~(PROT_MICROSOFT_NETWORKS_1_03 | PROT_WFWG) )
#define ARCH_VISTA    ( ARCH_WIN2K | PROT_SMB_2_001 )
#define ARCH_SAMBA    ( PROT_SAMBA )
#define ARCH_CIFSFS   ( PROT_POSIX_2 )
#define ARCH_OSX      ( PROT_NT_LM_0_12 | PROT_SMB_2_002 | PROT_SMB_2_FF )

/* List of supported protocols, most desired first */
static const struct {
	const char *proto_name;
	const char *short_name;
	NTSTATUS (*proto_reply_fn)(struct smb_request *req, uint16_t choice);
	int protocol_level;
} supported_protocols[] = {
	{"SMB 2.???",               "SMB2_FF",  reply_smb20ff,  PROTOCOL_SMB2_10},
	{"SMB 2.002",               "SMB2_02",  reply_smb2002,  PROTOCOL_SMB2_02},
	{"NT LANMAN 1.0",           "NT1",      reply_nt1,      PROTOCOL_NT1},
	{"NT LM 0.12",              "NT1",      reply_nt1,      PROTOCOL_NT1},
	{"POSIX 2",                 "NT1",      reply_nt1,      PROTOCOL_NT1},
	{"LANMAN2.1",               "LANMAN2",  reply_lanman2,  PROTOCOL_LANMAN2},
	{"LM1.2X002",               "LANMAN2",  reply_lanman2,  PROTOCOL_LANMAN2},
	{"Samba",                   "LANMAN2",  reply_lanman2,  PROTOCOL_LANMAN2},
	{"DOS LM1.2X002",           "LANMAN2",  reply_lanman2,  PROTOCOL_LANMAN2},
	{"LANMAN1.0",               "LANMAN1",  reply_lanman1,  PROTOCOL_LANMAN1},
	{"MICROSOFT NETWORKS 3.0",  "LANMAN1",  reply_lanman1,  PROTOCOL_LANMAN1},
	{NULL,NULL,NULL,0},
};

/****************************************************************************
 Reply to a negprot.
 conn POINTER CAN BE NULL HERE !
****************************************************************************/

void reply_negprot(struct smb_request *req)
{
	size_t choice = 0;
	int chosen_level = -1;
	bool choice_set = false;
	int protocol;
	const char *p;
	int protocols = 0;
	size_t num_cliprotos;
	char **cliprotos;
	size_t i;
	size_t converted_size;
	struct smbXsrv_connection *xconn = req->xconn;
	struct smbd_server_connection *sconn = req->sconn;
	bool signing_required = true;
	int max_proto;
	int min_proto;
	NTSTATUS status;

	START_PROFILE(SMBnegprot);

	if (xconn->smb1.negprot.done) {
		END_PROFILE(SMBnegprot);
		exit_server_cleanly("multiple negprot's are not permitted");
	}

	if (req->buflen == 0) {
		DEBUG(0, ("negprot got no protocols\n"));
		reply_nterror(req, NT_STATUS_INVALID_PARAMETER);
		END_PROFILE(SMBnegprot);
		return;
	}

	if (req->buf[req->buflen-1] != '\0') {
		DEBUG(0, ("negprot protocols not 0-terminated\n"));
		reply_nterror(req, NT_STATUS_INVALID_PARAMETER);
		END_PROFILE(SMBnegprot);
		return;
	}

	p = (const char *)req->buf + 1;

	num_cliprotos = 0;
	cliprotos = NULL;

	while (smbreq_bufrem(req, p) > 0) {

		char **tmp = talloc_realloc(talloc_tos(),
					    cliprotos,
					    char *,
					    num_cliprotos + 1);
		if (tmp == NULL) {
			DEBUG(0, ("talloc failed\n"));
			TALLOC_FREE(cliprotos);
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			END_PROFILE(SMBnegprot);
			return;
		}

		cliprotos = tmp;

		if (!pull_ascii_talloc(cliprotos, &cliprotos[num_cliprotos], p,
				       &converted_size)) {
			DEBUG(0, ("pull_ascii_talloc failed\n"));
			TALLOC_FREE(cliprotos);
			reply_nterror(req, NT_STATUS_NO_MEMORY);
			END_PROFILE(SMBnegprot);
			return;
		}

		DEBUG(3, ("Requested protocol [%s]\n",
			  cliprotos[num_cliprotos]));

		num_cliprotos += 1;
		p += strlen(p) + 2;
	}

	for (i=0; i<num_cliprotos; i++) {
		if (strcsequal(cliprotos[i], "Windows for Workgroups 3.1a")) {
			protocols |= PROT_WFWG;
		} else if (strcsequal(cliprotos[i], "DOS LM1.2X002")) {
			protocols |= PROT_DOS_LM1_2X002;
		} else if (strcsequal(cliprotos[i], "DOS LANMAN2.1")) {
			protocols |= PROT_DOS_LANMAN2_1;
		} else if (strcsequal(cliprotos[i], "LANMAN1.0")) {
			protocols |= PROT_LANMAN1_0;
		} else if (strcsequal(cliprotos[i], "NT LM 0.12")) {
			protocols |= PROT_NT_LM_0_12;
		} else if (strcsequal(cliprotos[i], "SMB 2.001")) {
			protocols |= PROT_SMB_2_001;
		} else if (strcsequal(cliprotos[i], "SMB 2.002")) {
			protocols |= PROT_SMB_2_002;
		} else if (strcsequal(cliprotos[i], "SMB 2.???")) {
			protocols |= PROT_SMB_2_FF;
		} else if (strcsequal(cliprotos[i], "LANMAN2.1")) {
			protocols |= PROT_LANMAN2_1;
		} else if (strcsequal(cliprotos[i], "LM1.2X002")) {
			protocols |= PROT_LM1_2X002;
		} else if (strcsequal(cliprotos[i], "MICROSOFT NETWORKS 1.03")) {
			protocols |= PROT_MICROSOFT_NETWORKS_1_03;
		} else if (strcsequal(cliprotos[i], "MICROSOFT NETWORKS 3.0")) {
			protocols |= PROT_MICROSOFT_NETWORKS_3_0;
		} else if (strcsequal(cliprotos[i], "PC NETWORK PROGRAM 1.0")) {
			protocols |= PROT_PC_NETWORK_PROGRAM_1_0;
		} else if (strcsequal(cliprotos[i], "XENIX CORE")) {
			protocols |= PROT_XENIX_CORE;
		} else if (strcsequal(cliprotos[i], "Samba")) {
			protocols = PROT_SAMBA;
			break;
		} else if (strcsequal(cliprotos[i], "POSIX 2")) {
			protocols = PROT_POSIX_2;
			break;
		}
	}

	switch ( protocols ) {
		/* Old CIFSFS can send one arch only, NT LM 0.12. */
		case PROT_NT_LM_0_12:
		case ARCH_CIFSFS:
			set_remote_arch(RA_CIFSFS);
			break;
		case ARCH_SAMBA:
			set_remote_arch(RA_SAMBA);
			break;
		case ARCH_WFWG:
			set_remote_arch(RA_WFWG);
			break;
		case ARCH_WIN95:
			set_remote_arch(RA_WIN95);
			break;
		case ARCH_WINNT:
			set_remote_arch(RA_WINNT);
			break;
		case ARCH_WIN2K:
			set_remote_arch(RA_WIN2K);
			break;
		case ARCH_VISTA:
			set_remote_arch(RA_VISTA);
			break;
		case ARCH_OS2:
			set_remote_arch(RA_OS2);
			break;
		case ARCH_OSX:
			set_remote_arch(RA_OSX);
			break;
		default:
			set_remote_arch(RA_UNKNOWN);
		break;
	}

	/* possibly reload - change of architecture */
	reload_services(sconn, conn_snum_used, true);

	/*
	 * Anything higher than PROTOCOL_SMB2_10 still
	 * needs to go via "SMB 2.???", which is marked
	 * as PROTOCOL_SMB2_10.
	 *
	 * The real negotiation happens via reply_smb20ff()
	 * using SMB2 Negotiation.
	 */
	max_proto = lp_server_max_protocol();
	if (max_proto > PROTOCOL_SMB2_10) {
		max_proto = PROTOCOL_SMB2_10;
	}
	min_proto = lp_server_min_protocol();
	if (min_proto > PROTOCOL_SMB2_10) {
		min_proto = PROTOCOL_SMB2_10;
	}

	/* Check for protocols, most desirable first */
	for (protocol = 0; supported_protocols[protocol].proto_name; protocol++) {
		i = 0;
		if ((supported_protocols[protocol].protocol_level <= max_proto) &&
		    (supported_protocols[protocol].protocol_level >= min_proto))
			while (i < num_cliprotos) {
				if (strequal(cliprotos[i],supported_protocols[protocol].proto_name)) {
					choice = i;
					chosen_level = supported_protocols[protocol].protocol_level;
					choice_set = true;
				}
				i++;
			}
		if (choice_set) {
			break;
		}
	}

	if (!choice_set) {
		bool ok;

		DBG_NOTICE("No protocol supported !\n");
		reply_smb1_outbuf(req, 1, 0);
		SSVAL(req->outbuf, smb_vwv0, NO_PROTOCOL_CHOSEN);

		ok = smb1_srv_send(xconn, (char *)req->outbuf, false, 0, false);
		if (!ok) {
			DBG_NOTICE("smb1_srv_send failed\n");
		}
		exit_server_cleanly("no protocol supported\n");
	}

	set_remote_proto(supported_protocols[protocol].short_name);
	reload_services(sconn, conn_snum_used, true);
	status = supported_protocols[protocol].proto_reply_fn(req, choice);
	if (!NT_STATUS_IS_OK(status)) {
		exit_server_cleanly("negprot function failed\n");
	}

	DEBUG(3,("Selected protocol %s\n",supported_protocols[protocol].proto_name));

	DBG_INFO("negprot index=%zu\n", choice);

	xconn->smb1.negprot.done = true;

	/* We always have xconn->smb1.signing_state also for >= SMB2_02 */
	signing_required = smb1_signing_is_mandatory(xconn->smb1.signing_state);
	if (signing_required && (chosen_level < PROTOCOL_NT1)) {
		exit_server_cleanly("SMB signing is required and "
			"client negotiated a downlevel protocol");
	}

	TALLOC_FREE(cliprotos);

	if (lp_async_smb_echo_handler() && (chosen_level < PROTOCOL_SMB2_02) &&
	    !fork_echo_handler(xconn)) {
		exit_server("Failed to fork echo handler");
	}

	END_PROFILE(SMBnegprot);
	return;
}