def trace(self, ea):
'''
Given an EA where an argument register is set, attempt to trace what
function call that argument is passed to.
@ea - The address of an instruction that modifies a function argument
register.
Returns a tuple of (function EA, argv index, argument register name) on
success.
Returns None on failure.
'''
insn = ida_shims.decode_insn(ea)
features = ida_shims.get_canon_feature(insn)
if self.arch.unknown:
return (None, None, None)
for n in range(0, len(self.CHANGE_OPND)):
ops = ida_shims.get_operands(insn)
if ops[n].type in [idaapi.o_reg, idaapi.o_displ, idaapi.o_phrase]:
try:
regname = self.arch.registers[ops[n].reg]
index = self.arch.argv.index(regname)
except ValueError:
continue
if features & self.CHANGE_OPND[n]:
ea = ea - (self.arch.delay_slot * self.arch.insn_size)
while True:
insn = ida_shims.decode_insn(ea)
if idaapi.is_call_insn(ea):
for xref in idautils.XrefsFrom(ea):
if xref.type in [idaapi.fl_CF, idaapi.fl_CN]:
return (xref.to, index, regname)
# If we couldn't figure out where the function call
# was going to, just quit
break
try:
is_block_end = idaapi.is_basic_block_end(ea)
except TypeError:
is_block_end = idaapi.is_basic_block_end(ea, True)
if is_block_end:
break
# TODO: Use idc.NextHead(ea) instead...
ea += self.arch.insn_size
return (None, None, None)
def argv(self, func):
'''
Attempts to identify what types of arguments are passed to a given
function. Currently unused.
'''
args = [None for x in self.arch.argv]
if not self.arch.unknown:
start_ea = ida_shims.start_ea(func)
for xref in idautils.XrefsTo(start_ea):
if idaapi.is_call_insn(xref.frm):
insn = ida_shims.decode_insn(xref.frm)
ea = xref.frm + (self.arch.delay_slot *
self.arch.insn_size)
end_ea = (xref.frm - (self.arch.insn_size * 10))
while ea >= end_ea:
if idaapi.is_basic_block_end(ea) or \
(ea != xref.frm and idaapi.is_call_insn(ea)):
break
insn = ida_shims.decode_insn(ea)
features = ida_shims.get_canon_feature(insn)
for n in range(0, len(self.CHANGE_OPND)):
ops = ida_shims.get_operands(insn)
if ops[n].type in [
idaapi.o_reg, idaapi.o_displ,
idaapi.o_phrase
]:
try:
regname = self.arch.registers[ops[n].reg]
index = self.arch.argv.index(regname)
except ValueError:
continue
if features & self.CHANGE_OPND[n]:
for xref in idautils.XrefsFrom(ea):
# TODO: Where is this xref type defined?
if xref.type == 1:
string = \
ida_shims.get_strlit_contents(
xref.to)
if string and len(string) > 4:
args[index] = str
break
ea -= self.arch.insn_size
yield args
def argc(self, function):
'''
Counts the number of arguments used by the specified function.
'''
argv = set()
notargv = set()
ea = ida_shims.start_ea(function)
end_ea = ida_shims.end_ea(function)
if self.arch.unknown:
return 0
while ea < end_ea:
insn = ida_shims.decode_insn(ea)
features = ida_shims.get_canon_feature(insn)
for n in range(0, len(self.USE_OPND)):
ops = ida_shims.get_operands(insn)
if ops[n].type in [
idaapi.o_reg, idaapi.o_displ, idaapi.o_phrase
]:
try:
regname = self.arch.registers[ops[n].reg]
index = self.arch.argv.index(regname)
except ValueError:
continue
if features & self.USE_OPND[n] and regname not in notargv:
argv.update(self.arch.argv[:index + 1])
for n in range(0, len(self.CHANGE_OPND)):
ops = ida_shims.get_operands(insn)
if ops[n].type in [
idaapi.o_reg, idaapi.o_displ, idaapi.o_phrase
]:
try:
regname = self.arch.registers[ops[n].reg]
index = self.arch.argv.index(regname)
except ValueError:
continue
if regname not in argv:
notargv.update(self.arch.argv[index:])
if argv.union(notargv) == set(self.arch.argv):
break
# TODO: Use idc.NextHead(ea) instead...
ea += self.arch.insn_size
return len(argv)
def _is_bad_instruction(self, ea, bad_instructions=['j', 'b'],
no_clobber=[]):
bad = False
mnem = ida_shims.print_insn_mnem(ea)
if mnem and mnem[0] in bad_instructions:
bad = True
else:
insn = ida_shims.decode_insn(ea)
feature = ida_shims.get_canon_feature(insn)
for register in no_clobber:
if (feature & idaapi.CF_CHG1) == idaapi.CF_CHG1:
if ida_shims.print_operand(ea, 0) == register:
bad = True
return bad
def _profile_function(self):
current_ea = ida_shims.get_screen_ea()
current_function = ida_shims.get_func_name(current_ea)
current_function_ea = ida_shims.get_name_ea_simple(current_function)
if current_function:
self.function = current_function
ea = ida_shims.get_func_attr(current_function_ea, idc.FUNCATTR_START)
end_ea = ida_shims.get_func_attr(current_function_ea, idc.FUNCATTR_END)
self.highlighted = ida_shims.get_highlighted_identifier()
while ea < end_ea and ea != idc.BADADDR and self.highlighted:
i = 0
match = False
optype = self.READ
insn = ida_shims.decode_insn(ea)
mnem = ida_shims.print_insn_mnem(ea)
if self.highlighted in mnem:
match = True
elif idaapi.is_call_insn(ea):
for xref in idautils.XrefsFrom(ea):
if xref.type != 21:
name = ida_shims.get_name(xref.to)
if name and self.highlighted in name:
match = True
break
else:
while True:
opnd = ida_shims.print_operand(ea, i)
if opnd:
if self.highlighted in opnd:
canon_feature = ida_shims.get_canon_feature(insn)
match = True
if canon_feature & self.OPND_WRITE_FLAGS[i]:
optype = self.WRITE
i += 1
else:
break
if not match:
comment = idc.GetCommentEx(ea, 0)
if comment and self.highlighted in comment:
match = True
else:
comment = idc.GetCommentEx(ea, 1)
if comment and self.highlighted in comment:
match = True
else:
comment = None
if match:
if ea > current_ea:
direction = self.DOWN
elif ea < current_ea:
direction = self.UP
else:
direction = self.THIS
self.xrefs[ea] = {
'offset': ida_shims.get_func_off_str(ea),
'mnem': mnem,
'type': optype,
'direction': direction,
'text': idc.GetDisasm(ea),
}
ea = ida_shims.next_head(ea)
