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BPCond.py
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BPCond.py
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# This is the breakpoint condition code.
# Every value inside the <<< >>> is an argument that will be replaced by "vtableAddress.py"
# The arguments are:
# * start_addr -> The offset of the virtual call from the beginning of its segment
# * register_vtable -> The register who points to the vtable
# * offset -> The offset of the relevant function from the vtable base pointer
def get_fixed_name_for_object(address, prefix=""):
"""
:param address: string, the object's address we want to calculate its offset
:param prefix: string, a prefix for the object name
:param suffix: string, a suffix for the object name
:return: returns the new name of the object with calculated offset from the base addr -> "prefix + offset + suffix"
!! In case the object (in this case function) doesn't starts with "sub_" the returned name will be the old name
"""
v_func_name = idc.get_func_name(int(address))
calc_func_name = int(address) - idc.get_segm_start(int(address))
if v_func_name[:4] == "sub_":
v_func_name = prefix + str(calc_func_name)
elif v_func_name == "":
v_func_name = prefix + str(calc_func_name) # The name will be the offset from the beginning of the segment
return v_func_name
def get_vtable_and_vfunc_addr(is_brac, register_vtable, offset):
"""
:param is_brac: number, if the call/ assignment is byRef the value is -1
:param register_vtable: string, the register used in the virtual call
:param offset: number, the offset of the function in the vtables used in on the bp opcode
:return: return the addresses of the vtable and the virtual function from the relevant register
"""
if is_brac == -1: # check it in both start addr and bp if both are [] than anf just than change is_brac
p_vtable_addr = idc.get_reg_value(register_vtable)
pv_func_addr = p_vtable_addr + offset
v_func_addr = get_wide_dword(pv_func_addr)
return p_vtable_addr, v_func_addr
else:
p_vtable_addr = get_wide_dword(idc.get_reg_value(register_vtable))
pv_func_addr = p_vtable_addr + offset
v_func_addr = get_wide_dword(pv_func_addr)
return p_vtable_addr, v_func_addr
def add_comment_to_struct_members(struct_id, vtable_func_offset, start_address):
# add comment to the vtable struct members
cur_cmt = idc.get_member_cmt(struct_id, vtable_func_offset, 1)
new_cmt = ""
if cur_cmt:
if cur_cmt[:23] != "Was called from offset:":
new_cmt = cur_cmt
else:
new_cmt = cur_cmt + ", " + start_address
else:
new_cmt = "Was called from offset: " + start_address
succ1 = idc.set_member_cmt(struct_id, vtable_func_offset, new_cmt, 1)
return succ1
def add_all_functions_to_struct(start_address, struct_id, p_vtable_addr, offset):
vtable_func_offset = 0
vtable_func_value = get_wide_dword(p_vtable_addr)
# Add all the vtable's functions to the vtable struct
while vtable_func_value != 0:
v_func_name = idc.get_func_name(vtable_func_value)
if v_func_name == '':
vtable_func_value = get_wide_dword(vtable_func_value)
v_func_name = idc.get_func_name(vtable_func_value)
if v_func_name == '':
print ("Error in adding functions to struct, at BP address::0x%08x" % (start_address))
# Change function name
v_func_name = get_fixed_name_for_object(int(vtable_func_value), "vfunc_")
idaapi.set_name(vtable_func_value, v_func_name, idaapi.SN_FORCE)
# Add to structure
succ = idc.add_struc_member(struct_id, v_func_name, vtable_func_offset , FF_DWORD, -1, 4)
if offset == vtable_func_offset:
add_comment_to_struct_members(struct_id, vtable_func_offset, start_address)
vtable_func_offset += 4
vtable_func_value = get_wide_dword(p_vtable_addr + vtable_func_offset)
def create_vtable_struct(start_address, vtable_name, p_vtable_addr, offset):
struct_name = vtable_name + "_struct"
struct_id = add_struc(-1, struct_name, 0)
if struct_id != idc.BADADDR:
add_all_functions_to_struct(start_address, struct_id, p_vtable_addr, offset)
idc.op_stroff(idautils.DecodeInstruction(int(idc.get_reg_value("eip"))), 1, struct_id, 0)
else:
struct_id = ida_struct.get_struc_id(struct_name)
# Checks if the struct exists, in this case the function offset will be added to the struct
if struct_id != idc.BADADDR:
idc.op_stroff(idautils.DecodeInstruction(int(idc.get_reg_value("eip"))), 1, struct_id, 0)
else:
print ("Failed to create struct: " + struct_name)
def do_logic(virtual_call_addr, register_vtable, offset):
# Checks if the assignment was beRef or byVal
is_brac_assign = idc.print_operand(int(idc.get_reg_value("eip")), 1).find('[')
# Checks if the assignment was beRef or byVal
call_addr = int(virtual_call_addr) + idc.get_segm_start(int(idc.get_reg_value("eip")))
is_brac_call = idc.print_operand(call_addr, 0).find('[')
is_brac = -1
if is_brac_assign != -1 and is_brac_call != -1:
is_brac = 0
# Get the adresses of the vtable and the virtual function from the relevant register:
p_vtable_addr, v_func_addr = get_vtable_and_vfunc_addr(is_brac, register_vtable, offset)
# Change the virtual function name (only in case the function has IDA's default name)
v_func_name = get_fixed_name_for_object(v_func_addr, "vfunc_")
idaapi.set_name(v_func_addr, v_func_name, idaapi.SN_FORCE)
# Change the vtable address name
vtable_name = get_fixed_name_for_object(p_vtable_addr, "vtable_")
idaapi.set_name(p_vtable_addr, vtable_name, idaapi.SN_FORCE)
# Add xref of the virtual call
idc.add_cref(int(idc.get_reg_value("eip")),v_func_addr , idc.XREF_USER)
# create the vtable struct
create_vtable_struct(int(virtual_call_addr), vtable_name, p_vtable_addr, offset)
virtual_call_addr = str(<<<start_addr>>>) # Offset from the beginning of its segment
#print "start_addr:", virtual_call_addr
register_vtable = "<<<register_vtable>>>"
offset = <<<offset>>>
if offset == "*":
opnd2 = idc.print_operand(virtual_call_addr, 1)
reg_offset = 0
place = opnd2.find('+')
if place != -1: # if the function is not the first in the vtable
sep = opnd2.find('*')
if sep != -1: # in case the offset is stored as a duplication of a register with a number
reg_offset = idc.get_reg_value(opnd2[place + 1: sep])
register = opnd2[opnd2.find('[') + 1: place]
if reg_offset:
offset = opnd2[sep + 1: opnd2.find(']')]
if offset.find('h') != -1:
int_offset = int(offset[:offset.find('h')], 16)
else:
int_offset = int(offset)
offset = int_offset * reg_offset
else:
offset = opnd2[place + 1: opnd2.find(']')]
try:
do_logic(virtual_call_addr, register_vtable, offset)
except:
print ("Error! at BP address: 0x%08x", idc.get_reg_value("eip"))
#idc.add_cref(0x000000013FA72ABB, 0x000000013FA71177, idc.XREF_USER | idc.fl_F)