smb_signing.c

samba-3.0.22.tar.gz 编译smb服务器的源码

	return True;
}

/***********************************************************
 SMB signing - Server implementation - check a MAC sent by server.
************************************************************/

static BOOL srv_check_incoming_message(char *inbuf, struct smb_sign_info *si, BOOL must_be_ok)
{
	BOOL good;
	struct smb_basic_signing_context *data = si->signing_context;
	uint32 reply_seq_number = data->send_seq_num;
	uint32 saved_seq;
	unsigned char calc_md5_mac[16];
	unsigned char *server_sent_mac;
	uint mid;

	if (!si->doing_signing)
		return True;

	if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
		DEBUG(1, ("srv_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
		return False;
	}

	mid = SVAL(inbuf, smb_mid);

	/* Is this part of a trans stream ? */
	if (data->trans_info && (data->trans_info->mid == mid)) {
		/* If so we don't increment the sequence. */
		reply_seq_number = data->trans_info->reply_seq_num;
	} else {
		/* We always increment the sequence number. */
		data->send_seq_num++;

		/* If we get an asynchronous oplock break reply and there
		 * isn't a reply pending we need to re-sync the sequence
		 * number.
		 */
		if (is_oplock_break(inbuf)) {
			DEBUG(10,("srv_check_incoming_message: oplock break at seq num %u\n", data->send_seq_num));
			data->send_seq_num++;
		}
	}

	saved_seq = reply_seq_number;
	simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);

	server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
	good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
	
	if (!good) {

		if (saved_seq) {
			DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u wanted SMB signature of\n",
					(unsigned int)saved_seq));
			dump_data(5, (const char *)calc_md5_mac, 8);

			DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u got SMB signature of\n",
						(unsigned int)reply_seq_number));
			dump_data(5, (const char *)server_sent_mac, 8);
		}
		
#if 1 /* JRATEST */
		{
			int i;
			reply_seq_number -= 5;
			for (i = 0; i < 10; i++, reply_seq_number++) {
				simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);
				if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
					DEBUG(0,("srv_check_incoming_message: out of seq. seq num %u matches. \
We were expecting seq %u\n", reply_seq_number, saved_seq ));
					break;
				}
			}
		}
#endif /* JRATEST */

	} else {
		DEBUG(10, ("srv_check_incoming_message: seq %u: (current is %u) got good SMB signature of\n", (unsigned int)reply_seq_number, (unsigned int)data->send_seq_num));
		dump_data(10, (const char *)server_sent_mac, 8);
	}

	return (signing_good(inbuf, si, good, saved_seq, must_be_ok));
}

/***********************************************************
 SMB signing - server API's.
************************************************************/

static struct smb_sign_info srv_sign_info = {
	null_sign_outgoing_message,
	null_check_incoming_message,
	null_free_signing_context,
	NULL,
	False,
	False,
	False,
	False
};

/***********************************************************
 Turn signing off or on for oplock break code.
************************************************************/

BOOL srv_oplock_set_signing(BOOL onoff)
{
	BOOL ret = srv_sign_info.doing_signing;
	srv_sign_info.doing_signing = onoff;
	return ret;
}

/***********************************************************
 Called to validate an incoming packet from the client.
************************************************************/

BOOL srv_check_sign_mac(char *inbuf, BOOL must_be_ok)
{
	/* Check if it's a session keepalive. */
	if(CVAL(inbuf,0) == SMBkeepalive)
		return True;

	return srv_sign_info.check_incoming_message(inbuf, &srv_sign_info, must_be_ok);
}

/***********************************************************
 Called to sign an outgoing packet to the client.
************************************************************/

void srv_calculate_sign_mac(char *outbuf)
{
	/* Check if it's a session keepalive. */
	/* JRA Paranioa test - do we ever generate these in the server ? */
	if(CVAL(outbuf,0) == SMBkeepalive)
		return;

	srv_sign_info.sign_outgoing_message(outbuf, &srv_sign_info);
}

/***********************************************************
 Called by server to defer an outgoing packet.
************************************************************/

void srv_defer_sign_response(uint16 mid)
{
	struct smb_basic_signing_context *data;

	if (!srv_sign_info.doing_signing)
		return;

	data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;

	if (!data)
		return;

	/*
	 * Ensure we only store this mid reply once...
	 */

	if (store_sequence_for_reply(&data->outstanding_packet_list, mid, data->send_seq_num)) {
		data->send_seq_num++;
	}
}

/***********************************************************
 Called to remove sequence records when a deferred packet is
 cancelled by mid. This should never find one....
************************************************************/

void srv_cancel_sign_response(uint16 mid)
{
	struct smb_basic_signing_context *data;
	uint32 dummy_seq;

	if (!srv_sign_info.doing_signing)
		return;

	data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;

	if (!data)
		return;

	DEBUG(10,("srv_cancel_sign_response: for mid %u\n", (unsigned int)mid ));

	while (get_sequence_for_reply(&data->outstanding_packet_list, mid, &dummy_seq))
		;
}

/***********************************************************
 Called by server negprot when signing has been negotiated.
************************************************************/

void srv_set_signing_negotiated(void)
{
	srv_sign_info.allow_smb_signing = True;
	srv_sign_info.negotiated_smb_signing = True;
	if (lp_server_signing() == Required)
		srv_sign_info.mandatory_signing = True;

	srv_sign_info.sign_outgoing_message = temp_sign_outgoing_message;
	srv_sign_info.check_incoming_message = temp_check_incoming_message;
	srv_sign_info.free_signing_context = temp_free_signing_context;
}

/***********************************************************
 Returns whether signing is active. We can't use sendfile or raw
 reads/writes if it is.
************************************************************/

BOOL srv_is_signing_active(void)
{
	return srv_sign_info.doing_signing;
}


/***********************************************************
 Returns whether signing is negotiated. We can't use it unless it was
 in the negprot.  
************************************************************/

BOOL srv_is_signing_negotiated(void)
{
	return srv_sign_info.negotiated_smb_signing;
}

/***********************************************************
 Returns whether signing is actually happening
************************************************************/

BOOL srv_signing_started(void)
{
	struct smb_basic_signing_context *data;

	if (!srv_sign_info.doing_signing) {
		return False;
	}

	data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
	if (!data)
		return False;

	if (data->send_seq_num == 0) {
		return False;
	}

	return True;
}


/***********************************************************
 Tell server code we are in a multiple trans reply state.
************************************************************/

void srv_signing_trans_start(uint16 mid)
{
	struct smb_basic_signing_context *data;

	if (!srv_sign_info.doing_signing)
		return;

	data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
	if (!data)
		return;

	data->trans_info = SMB_XMALLOC_P(struct trans_info_context);
	ZERO_STRUCTP(data->trans_info);

	data->trans_info->reply_seq_num = data->send_seq_num-1;
	data->trans_info->mid = mid;
	data->trans_info->send_seq_num = data->send_seq_num;

	DEBUG(10,("srv_signing_trans_start: storing mid = %u, reply_seq_num = %u, send_seq_num = %u \
data->send_seq_num = %u\n",
			(unsigned int)mid,
			(unsigned int)data->trans_info->reply_seq_num,
			(unsigned int)data->trans_info->send_seq_num,
			(unsigned int)data->send_seq_num ));
}

/***********************************************************
 Tell server code we are out of a multiple trans reply state.
************************************************************/

void srv_signing_trans_stop(void)
{
	struct smb_basic_signing_context *data;

	if (!srv_sign_info.doing_signing)
		return;

	data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
	if (!data || !data->trans_info)
		return;

	DEBUG(10,("srv_signing_trans_stop: removing mid = %u, reply_seq_num = %u, send_seq_num = %u \
data->send_seq_num = %u\n",
			(unsigned int)data->trans_info->mid,
			(unsigned int)data->trans_info->reply_seq_num,
			(unsigned int)data->trans_info->send_seq_num,
			(unsigned int)data->send_seq_num ));

	SAFE_FREE(data->trans_info);
	data->trans_info = NULL;
}

/***********************************************************
 Turn on signing from this packet onwards. 
************************************************************/

void srv_set_signing(const DATA_BLOB user_session_key, const DATA_BLOB response)
{
	struct smb_basic_signing_context *data;

	if (!user_session_key.length)
		return;

	if (!srv_sign_info.negotiated_smb_signing && !srv_sign_info.mandatory_signing) {
		DEBUG(5,("srv_set_signing: signing negotiated = %u, mandatory_signing = %u. Not allowing smb signing.\n",
			(unsigned int)srv_sign_info.negotiated_smb_signing,
			(unsigned int)srv_sign_info.mandatory_signing ));
		return;
	}

	/* Once we've turned on, ignore any more sessionsetups. */
	if (srv_sign_info.doing_signing) {
		return;
	}
	
	if (srv_sign_info.free_signing_context)
		srv_sign_info.free_signing_context(&srv_sign_info);
	
	srv_sign_info.doing_signing = True;

	data = SMB_XMALLOC_P(struct smb_basic_signing_context);
	memset(data, '\0', sizeof(*data));

	srv_sign_info.signing_context = data;
	
	data->mac_key = data_blob(NULL, response.length + user_session_key.length);

	memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
	if (response.length)
		memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);

	dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);

	DEBUG(3,("srv_set_signing: turning on SMB signing: signing negotiated = %s, mandatory_signing = %s.\n",
				BOOLSTR(srv_sign_info.negotiated_smb_signing),
			 	BOOLSTR(srv_sign_info.mandatory_signing) ));

	/* Initialise the sequence number */
	data->send_seq_num = 0;

	/* Initialise the list of outstanding packets */
	data->outstanding_packet_list = NULL;

	srv_sign_info.sign_outgoing_message = srv_sign_outgoing_message;
	srv_sign_info.check_incoming_message = srv_check_incoming_message;
	srv_sign_info.free_signing_context = simple_free_signing_context;
}