"""vtable_dump.py: IDAPython script to dump a linux vtable (and a reconstructed windows one) from a binary."""

"""

This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.

Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.

"""

__author__ = "Asher Baker"

__copyright__ = "Copyright 2012, Asher Baker"

__license__ = "zlib/libpng"

import re

"""

Output Format:"

    VTable for <1>: (<2>, <3>)

    Lin    Win Function

    <4><5> <6> <7>

    <4><5> <6> <7>

    ...

    <4><5> <6> <7>

1: Classname

2: VTable Offset

3: Linux This Pointer Offset

4: "T" if the function is a MI thunk

5: Linux VTable Index

6: Windows VTable Index

7: Function Signature

"""

catchclass = False

innerclass = ""

classname = None

offsetdata = {}

def ExtractTypeInfo(ea, level = 0):

	global catchclass

	global innerclass

	global classname

	global offsetdata

	# Param needed to support old IDAPython versions

	end = NextNotTail(ea)

	# Skip vtable

	ea += 4

	# Get type name

	name = Demangle("_Z" + GetString(Dword(ea)), GetLongPrm(INF_LONG_DN))

	ea += 4

	if classname is None and level == 0:

		classname = name

	if catchclass:

		innerclass = name

		catchclass = False

	print " %*s%s" % (level, "", name)

	if not ea < end: # Base Type

		pass

	elif isData(GetFlags(Dword(ea))): # Single Inheritance

		ExtractTypeInfo(Dword(ea), level + 1)

		ea += 4

	else: # Multiple Inheritance

		ea += 8

		while ea < end:

			catchclass = True

			ExtractTypeInfo(Dword(ea), level + 1)

			ea += 4

			offset = Dword(ea)

			ea += 4

			#print "%*s Offset: 0x%06X" % (level, "", offset >> 8)

			if (offset >> 8) != 0:

				offsetdata[offset >> 8] = innerclass

# Source: http://stackoverflow.com/a/9147327

def twos_comp(val, bits):

	"""compute the 2's compliment of int value val"""

	if (val & (1 << (bits - 1))) != 0:

		val = val - (1 << bits)

	return val

def Analyze():

	SetStatus(IDA_STATUS_WORK)

	if GetLongPrm(INF_COMPILER).id != COMP_GNU:

		Warning("This script is for binaries compiled with GCC only.")

		SetStatus(IDA_STATUS_READY)

		return

	ea = ScreenEA()

	if not isHead(GetFlags(ea)):

		# Param needed to support old IDAPython versions

		ea = PrevHead(ea, 0)

	end = NextNotTail(ea)

	name = Demangle(Name(ea), GetLongPrm(INF_LONG_DN))

	if ea == BADADDR or name is None or not re.search(r"vf?table(?: |'\{)for", name):

		Warning("No vtable selected!\nSelect vtable block first.")

		SetStatus(IDA_STATUS_READY)

		return

	linux_vtable = []

	temp_windows_vtable = []

	other_linux_vtables = {}

	other_thunk_linux_vtables = {}

	temp_other_windows_vtables = {}

	# Extract vtable

	while ea < end:

		# Read thisoffs

		offset = -twos_comp(Dword(ea), 32)

		ea += 4

		# Read typeinfo address

		typeinfo = Dword(ea)

		ea += 4

		if offset == 0: # We only need to read this once

			print "Inheritance Tree:"

			ExtractTypeInfo(typeinfo)

		while ea < end and isCode(GetFlags(Dword(ea))):

			name = Name(Dword(ea))

			demangled = Demangle(name, GetLongPrm(INF_LONG_DN))

			#print "Name: %s, Demangled: %s" % (name, demangled)

			name = demangled if demangled else name

			if offset == 0:

				linux_vtable.append(name)

				temp_windows_vtable.append(name)

			else:

				if offset not in other_linux_vtables:

					other_linux_vtables[offset] = []

					temp_other_windows_vtables[offset] = []

					other_thunk_linux_vtables[offset] = []

				if "`non-virtual thunk to'" in name:

					other_linux_vtables[offset].append(name[22:])

					other_thunk_linux_vtables[offset].append(name[22:])

					temp_other_windows_vtables[offset].append(name[22:])

				else:

					other_linux_vtables[offset].append(name)

					temp_other_windows_vtables[offset].append(name)

				# MI entry, strip "`non-virtual thunk to'" and remove from list

				#     But not if it's a dtor... what the hell is this.

				if "`non-virtual thunk to'" in name and "::~" not in name:

					name = name[22:]

					#print "Stripping '%s' from windows vtable." % (name)

					temp_windows_vtable.remove(name)

			ea += 4

	for i, v in enumerate(temp_windows_vtable):

		if "::~" in v:

			#print "Found destructor at index %d: %s" % (i, v)

			del temp_windows_vtable[i]

			break

	windows_vtable = []

	overload_stack = []

	prev_function = ""

	prev_symbol = ""

	for v in temp_windows_vtable:

		function = v.split("(", 1)[0]

		if function == prev_function:

			# If we don't have a stack, we need to push the last function on first

			if len(overload_stack) == 0:

				# We will have added this in the previous run, remove it again...

				windows_vtable.pop()

				#print "Storing '%s' (!)" % (prev_symbol)

				overload_stack.append(prev_symbol)

			#print "Storing '%s'" % (v)

			overload_stack.append(v)

		else:

			# If we've moved onto something new, dump the stack first

			while len(overload_stack) > 0:

				windows_vtable.append(overload_stack.pop())

			windows_vtable.append(v)

		prev_function = function

		prev_symbol = v

	# If there is anything left in the stack, dump it

	while len(overload_stack) > 0:

		windows_vtable.append(overload_stack.pop())

	print "\nVTable for %s: (0, 0)" % (classname)

	print " Lin  Win Function"

	for i, v in enumerate(linux_vtable):

		if "__cxa_pure_virtual" in v:

			print "P%3d" % (i)

			continue

		winindex = windows_vtable.index(v) if v in windows_vtable else None

		if winindex is not None:

			print "%4d %4d %s" % (i, winindex, v)

		else:

			print "%4d      %s" % (i, v)

	for k in temp_other_windows_vtables:

		for i, v in enumerate(temp_other_windows_vtables[k]):

			if v.find("::~") != -1:

				#print "Found destructor at index %d: %s" % (i, v)

				del temp_other_windows_vtables[k][i]

				break

	other_windows_vtables = {}

	for k in temp_other_windows_vtables:

		other_windows_vtables[k] = []

		overload_stack = []

		prev_function = ""

		prev_symbol = ""

		for v in temp_other_windows_vtables[k]:

			function = v.split("(", 1)[0]

			if function == prev_function:

				if len(overload_stack) == 0:

					other_windows_vtables[k].pop()

					#print "Storing '%s' (!)" % (prev_symbol)

					overload_stack.append(prev_symbol)

				#print "Storing '%s'" % (v)

				overload_stack.append(v)

			else:

				if len(overload_stack) > 0:

					while len(overload_stack) > 0:

						other_windows_vtables[k].append(overload_stack.pop())

				other_windows_vtables[k].append(v)

			prev_function = function

			prev_symbol = v

	for k in other_linux_vtables:

		print "\nVTable for %s: (%d, %d)" % (offsetdata[k], offsetdata.keys().index(k) + 1, k)

		print " Lin  Win Function"

		for i, v in enumerate(other_linux_vtables[k]):

			if "__cxa_pure_virtual" in v:

				print "P%3d" % (i)

				continue

			winindex = other_windows_vtables[k].index(v)

			if v not in other_thunk_linux_vtables[k]:

				print "%4d %4d %s" % (i, winindex, v)

			else:

				print "T%3d %4d %s" % (i, winindex, v)

	SetStatus(IDA_STATUS_READY)

if __name__ == '__main__':

	Analyze()