# SECUREAUTH LABS. Copyright 2018 SecureAuth Corporation. All rights reserved.
#
# This software is provided under under a slightly modified version
# of the Apache Software License. See the accompanying LICENSE file
# for more information.
#
# Author: Alberto Solino (@agsolino)
#
# Description: A Windows Registry Library Parser
#
# Data taken from https://bazaar.launchpad.net/~guadalinex-members/dumphive/trunk/view/head:/winreg.txt
# http://sentinelchicken.com/data/TheWindowsNTRegistryFileFormat.pdf
#
#
# ToDo:
#
# [ ] Parse li records, probable the same as the ri but couldn't find any to probe

from __future__ import division
from __future__ import print_function
import sys
from struct import unpack
import ntpath
from six import b

from impacket import LOG
from impacket.structure import Structure, hexdump


# Constants

ROOT_KEY        = 0x2c
REG_NONE        = 0x00
REG_SZ          = 0x01
REG_EXPAND_SZ   = 0x02
REG_BINARY      = 0x03
REG_DWORD       = 0x04
REG_MULTISZ     = 0x07
REG_QWORD       = 0x0b

# Structs
class REG_REGF(Structure):
    structure = (
        ('Magic','"regf'),
        ('Unknown','<L=0'),
        ('Unknown2','<L=0'),
        ('lastChange','<Q=0'),
        ('MajorVersion','<L=0'),
        ('MinorVersion','<L=0'),
        ('0','<L=0'),
        ('11','<L=0'),
        ('OffsetFirstRecord','<L=0'),
        ('DataSize','<L=0'),
        ('1111','<L=0'),
        ('Name','48s=""'),
        ('Remaining1','411s=b""'),
        ('CheckSum','<L=0xffffffff'), # Sum of all DWORDs from 0x0 to 0x1FB
        ('Remaining2','3585s=b""'),
    )

class REG_HBIN(Structure):
    structure = (
        ('Magic','"hbin'),
        ('OffsetFirstHBin','<L=0'),
        ('OffsetNextHBin','<L=0'),
        ('BlockSize','<L=0'),
    )

class REG_HBINBLOCK(Structure):
    structure = (
        ('DataBlockSize','<l=0'),
        ('_Data','_-Data','self["DataBlockSize"]*(-1)-4'),
        ('Data',':'),
    )

class REG_NK(Structure):
    structure = (
        ('Magic','"nk'),
        ('Type','<H=0'),
        ('lastChange','<Q=0'),
        ('Unknown','<L=0'),
        ('OffsetParent','<l=0'),
        ('NumSubKeys','<L=0'),
        ('Unknown2','<L=0'),
        ('OffsetSubKeyLf','<l=0'),
        ('Unknown3','<L=0'),
        ('NumValues','<L=0'),
        ('OffsetValueList','<l=0'),
        ('OffsetSkRecord','<l=0'),
        ('OffsetClassName','<l=0'),
        ('UnUsed','20s=b""'),
        ('NameLength','<H=0'),
        ('ClassNameLength','<H=0'),
        ('_KeyName','_-KeyName','self["NameLength"]'),
        ('KeyName',':'),
    )

class REG_VK(Structure):
    structure = (
        ('Magic','"vk'),
        ('NameLength','<H=0'),
        ('DataLen','<l=0'),
        ('OffsetData','<L=0'),
        ('ValueType','<L=0'),
        ('Flag','<H=0'),
        ('UnUsed','<H=0'),
        ('_Name','_-Name','self["NameLength"]'),
        ('Name',':'),
    )

class REG_LF(Structure):
    structure = (
        ('Magic','"lf'),
        ('NumKeys','<H=0'),
        ('HashRecords',':'),
    )

class REG_LH(Structure):
    structure = (
        ('Magic','"lh'),
        ('NumKeys','<H=0'),
        ('HashRecords',':'),
    )

class REG_RI(Structure):
    structure = (
        ('Magic','"ri'),
        ('NumKeys','<H=0'),
        ('HashRecords',':'),
    )

class REG_SK(Structure):
    structure = (
        ('Magic','"sk'),
        ('UnUsed','<H=0'),
        ('OffsetPreviousSk','<l=0'),
        ('OffsetNextSk','<l=0'),
        ('UsageCounter','<L=0'),
        ('SizeSk','<L=0'),
        ('Data',':'),
    )

class REG_HASH(Structure):
    structure = (
        ('OffsetNk','<L=0'),
        ('KeyName','4s=b""'),
    )

StructMappings = {b'nk': REG_NK,
                  b'vk': REG_VK,
                  b'lf': REG_LF,
                  b'lh': REG_LH,
                  b'ri': REG_RI,
                  b'sk': REG_SK,
                 }

class Registry:
    def __init__(self, hive, isRemote = False):
        self.__hive = hive
        if isRemote is True:
            self.fd = self.__hive
            self.__hive.open()
        else:
            self.fd = open(hive,'rb')
        data = self.fd.read(4096)
        self.__regf = REG_REGF(data)
        self.indent = ''
        self.rootKey = self.__findRootKey()
        if self.rootKey is None:
            LOG.error("Can't find root key!")
        elif self.__regf['MajorVersion'] != 1 and self.__regf['MinorVersion'] > 5:
            LOG.warning("Unsupported version (%d.%d) - things might not work!" % (self.__regf['MajorVersion'], self.__regf['MinorVersion']))

    def close(self):
        self.fd.close()

    def __del__(self):
        self.close()

    def __findRootKey(self):
        self.fd.seek(0,0)
        data = self.fd.read(4096)
        while len(data) > 0:
            try:
                hbin = REG_HBIN(data[:0x20])
                # Read the remaining bytes for this hbin
                data += self.fd.read(hbin['OffsetNextHBin']-4096)
                data = data[0x20:]
                blocks = self.__processDataBlocks(data)
                for block in blocks:
                    if isinstance(block, REG_NK):
                        if block['Type'] == ROOT_KEY:
                            return block
            except Exception as e:
                pass
            data = self.fd.read(4096)

        return None


    def __getBlock(self, offset):
        self.fd.seek(4096+offset,0)
        sizeBytes = self.fd.read(4)
        data = sizeBytes + self.fd.read(unpack('<l',sizeBytes)[0]*-1-4)
        if len(data) == 0:
            return None
        else:
            block = REG_HBINBLOCK(data)
            if block['Data'][:2] in StructMappings:
                return StructMappings[block['Data'][:2]](block['Data'])
            else:
                LOG.debug("Unknown type 0x%s" % block['Data'][:2])
                return block
            return None

    def __getValueBlocks(self, offset, count):
        valueList = []
        res = []
        self.fd.seek(4096+offset,0)
        for i in range(count):
            valueList.append(unpack('<l',self.fd.read(4))[0])

        for valueOffset in valueList:
            if valueOffset > 0:
                block = self.__getBlock(valueOffset)
                res.append(block)
        return res

    def __getData(self, offset, count):
        self.fd.seek(4096+offset, 0)
        return self.fd.read(count)[4:]

    def __processDataBlocks(self,data):
        res = []
        while len(data) > 0:
            #blockSize = unpack('<l',data[:calcsize('l')])[0]
            blockSize = unpack('<l',data[:4])[0]
            block = REG_HBINBLOCK()
            if blockSize > 0:
                tmpList = list(block.structure)
                tmpList[1] = ('_Data','_-Data','self["DataBlockSize"]-4')
                block.structure =  tuple(tmpList)

            block.fromString(data)
            blockLen = len(block)

            if block['Data'][:2] in StructMappings:
                block = StructMappings[block['Data'][:2]](block['Data'])

            res.append(block)
            data = data[blockLen:]
        return res

    def __getValueData(self, rec):
        # We should receive a VK record
        if rec['DataLen'] == 0:
            return ''
        if rec['DataLen'] < 0:
            # if DataLen < 5 the value itself is stored in the Offset field
            return rec['OffsetData']
        else:
            return self.__getData(rec['OffsetData'], rec['DataLen']+4)

    def __getLhHash(self, key):
        res = 0
        for bb in key.upper():
            res *= 37
            res += ord(bb)
        return res % 0x100000000

    def __compareHash(self, magic, hashData, key):
        if magic == 'lf':
            hashRec = REG_HASH(hashData)
            if hashRec['KeyName'].strip(b'\x00') == b(key[:4]):
                return hashRec['OffsetNk']
        elif magic == 'lh':
            hashRec = REG_HASH(hashData)
            if unpack('<L',hashRec['KeyName'])[0] == self.__getLhHash(key):
                return hashRec['OffsetNk']
        elif magic == 'ri':
            # Special case here, don't know exactly why, an ri pointing to a NK :-o
            offset = unpack('<L', hashData[:4])[0]
            nk = self.__getBlock(offset)
            if nk['KeyName'] == key:
                return offset
        else:
            LOG.critical("UNKNOWN Magic %s" % magic)
            sys.exit(1)

        return None

    def __findSubKey(self, parentKey, subKey):
        lf = self.__getBlock(parentKey['OffsetSubKeyLf'])
        if lf is not None:
            data = lf['HashRecords']
            # Let's search the hash records for the name
            if lf['Magic'] == 'ri':
                # ri points to lf/lh records, so we must parse them before
                records = b''
                for i in range(lf['NumKeys']):
                    offset = unpack('<L', data[:4])[0]
                    l = self.__getBlock(offset)
                    records = records + l['HashRecords'][:l['NumKeys']*8]
                    data = data[4:]
                data = records

            #for record in range(lf['NumKeys']):
            for record in range(parentKey['NumSubKeys']):
                hashRec = data[:8]
                res = self.__compareHash(lf['Magic'], hashRec, subKey)
                if res is not None:
                    # We have a match, now let's check the whole record
                    nk = self.__getBlock(res)
                    if nk['KeyName'].decode('utf-8') == subKey:
                        return nk
                data = data[8:]

        return None

    def __walkSubNodes(self, rec):
        nk = self.__getBlock(rec['OffsetNk'])
        if isinstance(nk, REG_NK):
            print("%s%s" % (self.indent, nk['KeyName'].decode('utf-8')))
            self.indent += '  '
            if nk['OffsetSubKeyLf'] < 0:
                self.indent = self.indent[:-2]
                return
            lf = self.__getBlock(nk['OffsetSubKeyLf'])
        else:
            lf = nk

        data = lf['HashRecords']

        if lf['Magic'] == 'ri':
            # ri points to lf/lh records, so we must parse them before
            records = ''
            for i in range(lf['NumKeys']):
                offset = unpack('<L', data[:4])[0]
                l = self.__getBlock(offset)
                records = records + l['HashRecords'][:l['NumKeys']*8]
                data = data[4:]
            data = records

        for key in range(lf['NumKeys']):
            hashRec = REG_HASH(data[:8])
            self.__walkSubNodes(hashRec)
            data = data[8:]

        if isinstance(nk, REG_NK):
            self.indent = self.indent[:-2]

    def walk(self, parentKey):
        key = self.findKey(parentKey)

        if key is None or key['OffsetSubKeyLf'] < 0:
            return

        lf = self.__getBlock(key['OffsetSubKeyLf'])
        data = lf['HashRecords']
        for record in range(lf['NumKeys']):
            hashRec = REG_HASH(data[:8])
            self.__walkSubNodes(hashRec)
            data = data[8:]

    def findKey(self, key):
        # Let's strip '\' from the beginning, except for the case of
        # only asking for the root node
        if key[0] == '\\' and len(key) > 1:
            key = key[1:]

        parentKey = self.rootKey
        if len(key) > 0 and key[0]!='\\':
            for subKey in key.split('\\'):
                res = self.__findSubKey(parentKey, subKey)
                if res is not None:
                    parentKey = res
                else:
                    #LOG.error("Key %s not found!" % key)
                    return None

        return parentKey

    def printValue(self, valueType, valueData):
        if valueType == REG_SZ or valueType == REG_EXPAND_SZ:
            if type(valueData) is int:
                print('NULL')
            else:
                print("%s" % (valueData.decode('utf-16le')))
        elif valueType == REG_BINARY:
            print('')
            hexdump(valueData, self.indent)
        elif valueType == REG_DWORD:
            print("%d" % valueData)
        elif valueType == REG_QWORD:
            print("%d" % (unpack('<Q',valueData)[0]))
        elif valueType == REG_NONE:
            try:
                if len(valueData) > 1:
                    print('')
                    hexdump(valueData, self.indent)
                else:
                    print(" NULL")
            except:
                print(" NULL")
        elif valueType == REG_MULTISZ:
            print("%s" % (valueData.decode('utf-16le')))
        else:
            print("Unknown Type 0x%x!" % valueType)
            hexdump(valueData)

    def enumKey(self, parentKey):
        res = []
        # If we're here.. we have a valid NK record for the key
        # Now let's searcht the subkeys
        if parentKey['NumSubKeys'] > 0:
            lf = self.__getBlock(parentKey['OffsetSubKeyLf'])
            data = lf['HashRecords']

            if lf['Magic'] == 'ri':
                # ri points to lf/lh records, so we must parse them before
                records = ''
                for i in range(lf['NumKeys']):
                    offset = unpack('<L', data[:4])[0]
                    l = self.__getBlock(offset)
                    records = records + l['HashRecords'][:l['NumKeys']*8]
                    data = data[4:]
                data = records

            for i in range(parentKey['NumSubKeys']):
                hashRec = REG_HASH(data[:8])
                nk = self.__getBlock(hashRec['OffsetNk'])
                data = data[8:]
                res.append('%s'%nk['KeyName'].decode('utf-8'))
        return res

    def enumValues(self,key):
        # If we're here.. we have a valid NK record for the key
        # Now let's search its values
        resp = []
        if key['NumValues'] > 0:
            valueList = self.__getValueBlocks(key['OffsetValueList'], key['NumValues']+1)

            for value in valueList:
                if value['Flag'] > 0:
                    resp.append(value['Name'])
                else:
                    resp.append(b'default')

        return resp

    def getValue(self, keyValue):
        # returns a tuple with (ValueType, ValueData) for the requested keyValue
        regKey = ntpath.dirname(keyValue)
        regValue = ntpath.basename(keyValue)

        key = self.findKey(regKey)

        if key is None:
            return None

        if key['NumValues'] > 0:
            valueList = self.__getValueBlocks(key['OffsetValueList'], key['NumValues']+1)

            for value in valueList:
                if value['Name'] == b(regValue):
                    return value['ValueType'], self.__getValueData(value)
                elif regValue == 'default' and value['Flag'] <=0:
                    return value['ValueType'], self.__getValueData(value)

        return None

    def getClass(self, className):

        key = self.findKey(className)

        if key is None:
            return None

        #print key.dump()
        if key['OffsetClassName'] > 0:
            value = self.__getBlock(key['OffsetClassName'])
            return value['Data']
