node-smb-server
Version:
A Pure JavaScript SMB Server Implementation
234 lines (211 loc) • 8.53 kB
JavaScript
/*
* Copyright 2015 Adobe Systems Incorporated. All rights reserved.
* This file is licensed to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License. You may obtain a copy
* of the License at http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under
* the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
* OF ANY KIND, either express or implied. See the License for the specific language
* governing permissions and limitations under the License.
*/
'use strict';
var path = require('path');
var fs = require('fs');
var put = require('put');
var binary = require('binary');
var logger = require('winston').loggers.get('smb');
var _ = require('lodash');
var ntstatus = require('../../ntstatus');
var smb = require('../handler');
var SMB = require('../constants');
var utils = require('../../utils');
var subCmdHandlers = {};
function loadSubCmdHandlers() {
var p = path.join(__dirname, 'nttrans');
var files = fs.readdirSync(p);
for (var i = 0; i < files.length; i++) {
var f = files[i];
var stat = fs.statSync(path.resolve(p, f));
if (stat.isDirectory()) {
continue;
}
if (f.substr(-3) === '.js') {
f = f.slice(0, -3);
subCmdHandlers[f] = require(path.resolve(p, f));
}
}
}
loadSubCmdHandlers();
/**
* SMB_COM_NT_TRANSACT (0xA0): SMB_COM_NT_TRANSACT subcommands extend the file system feature access
* offered by SMB_COM_TRANSACTION2.
*
* @param {Object} msg - an SMB message object
* @param {Number} commandId - the command id
* @param {Buffer} commandParams - the command parameters
* @param {Buffer} commandData - the command data
* @param {Number} commandParamsOffset - the command parameters offset within the SMB
* @param {Number} commandDataOffset - the command data offset within the SMB
* @param {Object} connection - an SMBConnection instance
* @param {Object} server - an SMBServer instance
* @param {Function} cb callback called with the command's result
* @param {Object} cb.result - an object with the command's result params and data
* or null if the handler already sent the response and
* no further processing is required by the caller
* @param {Number} cb.result.status
* @param {Buffer} cb.result.params
* @param {Buffer} cb.result.data
*/
function handle(msg, commandId, commandParams, commandData, commandParamsOffset, commandDataOffset, connection, server, cb) {
// decode params
var parser = binary.parse(commandParams);
var paramsObj = parser.word8le('maxSetupCount')
.skip(2) // reserved1
.word32le('totalParameterCount') // bytes (not words)
.word32le('totalDataCount')
.word32le('maxParameterCount') // bytes (not words)
.word32le('maxDataCount')
.word32le('parameterCount') // bytes (not words)
.word32le('parameterOffset')
.word32le('dataCount')
.word32le('dataOffset')
.word8le('setupCount')
.word16le('function')
.buffer('setup', 2 * parser.vars['setupCount'])
.vars;
_.assign(msg, paramsObj);
var result;
msg.subCommandId = msg.function;
var subCommand = SMB.NTTRANS_SUBCOMMAND_TO_STRING[msg.subCommandId];
if (!subCommand) {
logger.error('encountered invalid subcommand 0x%s', msg.subCommandId.toString(16));
result = {
status: ntstatus.STATUS_SMB_BAD_COMMAND,
params: utils.EMPTY_BUFFER,
data: utils.EMPTY_BUFFER
};
process.nextTick(function () { cb(result); });
return;
}
// decode data
// calculate pad length for 4 byte alignment
var off = utils.calculatePadLength(commandDataOffset, 4);
var NT_Trans_Parameters = commandData.slice(off, off + msg.parameterCount);
off += msg.parameterCount;
// calculate pad length for 4 byte alignment
off += utils.calculatePadLength(off, 4);
var NT_Trans_Data = commandData.slice(off, off + msg.dataCount);
off += msg.dataCount;
var subParams = msg.buf.slice(msg.parameterOffset, msg.parameterOffset + msg.parameterCount);
var subData = msg.buf.slice(msg.dataOffset, msg.dataOffset + msg.dataCount);
logger.debug('[%s][%s] totalParameterCount: %d, parameterCount: %d, totalDataCount: %d, dataCount: %d, setup: 0x%s', SMB.COMMAND_TO_STRING[commandId].toUpperCase(), subCommand.toUpperCase(), msg.totalParameterCount, msg.parameterCount, msg.totalDataCount, msg.dataCount, msg.setup.toString('hex'));
if (msg.parameterCount < msg.totalParameterCount || msg.dataCount < msg.totalDataCount) {
// todo support nt_transact_secondary messages (reassembling chunked nt_transact messages)
logger.error('chunked nt_transact messages are not yet supported.');
result = {
status: ntstatus.STATUS_NOT_IMPLEMENTED,
params: utils.EMPTY_BUFFER,
data: utils.EMPTY_BUFFER
};
process.nextTick(function () { cb(result); });
return;
}
// invoke subcommand handler
var handler = subCmdHandlers[subCommand];
if (handler) {
if (msg.subCommandId === 0x0004) { // nt_transact_notify_change
// nt_transact_notify_change has a special contract:
// it does send an immediate null or error response potentially followed
// by an out-of-band response with the change notification at some later point in time.
handler(msg, msg.subCommandId, subParams, subData, msg.parameterOffset, msg.dataOffset, connection, server, function (result) {
var res = buildResponse(result);
if (res && res.status === ntstatus.STATUS_SUCCESS) {
// send out-of-band response (one shot notification)
msg.commands[0].params = res.params;
msg.commands[0].data = res.data;
smb.sendResponse(msg, ntstatus.STATUS_SUCCESS, connection, server, function (err) {
if (err) {
logger.error('[%s] failed to send notification response', subCommand.toUpperCase(), err);
}
});
} else {
// null or error response: invoke callback immediately
cb(res);
}
});
} else {
handler(msg, msg.subCommandId, subParams, subData, msg.parameterOffset, msg.dataOffset, connection, server, function (result) {
// build and return response
cb(buildResponse(result));
});
}
} else {
logger.error('encountered unsupported subcommand 0x%s \'%s\'', msg.subCommandId.toString(16), subCommand.toUpperCase());
result = {
status: ntstatus.STATUS_NOT_IMPLEMENTED,
params: utils.EMPTY_BUFFER,
data: utils.EMPTY_BUFFER
};
cb(result);
}
}
function buildResponse(subResult) {
if (!subResult) {
// special case (see e.g. 'nt_transact_notify_change' handler): no further processing required
return null;
}
if (subResult.status !== ntstatus.STATUS_SUCCESS) {
return {
status: subResult.status,
params: utils.EMPTY_BUFFER,
data: utils.EMPTY_BUFFER
};
}
// build response
var subParams = subResult.params;
var subData = subResult.data;
var setup = subResult.setup || utils.EMPTY_BUFFER;
// nt_transact response have a params length of 36 (18 words) plus length of setup
var paramsLength = 36 + setup.length;
var dataOffset = SMB.SMB_MIN_LENGTH + paramsLength;
// calculate offsets and paddings
var subParamsOffset, subDataOffset, pad1, pad2;
var off = dataOffset;
pad1 = utils.calculatePadLength(off, 4);
off += pad1;
subParamsOffset = off;
off += subParams.length;
pad2 = utils.calculatePadLength(off, 4);
off += pad2;
subDataOffset = off;
off += subData.length;
// params
var paramsOut = put();
paramsOut.pad(3) // Reserved1
.word32le(subParams.length) // TotalParameterCount
.word32le(subData.length) // TotalDataCount
.word32le(subParams.length) // ParameterCount
.word32le(subParamsOffset) // ParameterOffset
.word32le(0) // ParameterDisplacement
.word32le(subData.length) // DataCount
.word32le(subDataOffset) // DataOffset
.word32le(0) // DataDisplacement
.word8(setup.length ? setup.length / 2 : 0) // SetupCount
.put(setup); // Setup
var params = paramsOut.buffer();
// data
var dataOut = put();
dataOut.pad(pad1)
.put(subParams)
.pad(pad2)
.put(subData);
var data = dataOut.buffer();
// return result
return {
status: ntstatus.STATUS_SUCCESS,
params: params,
data: data
};
}
module.exports = handle;