def __init__(self, addr_list, raw):
"""
addr_list = list of addresses of the gadget (if duplicate gadgets)
raw = raw string of gadget asm
"""
# Check the type of the gadget
# Check for 'int 0x80' gadgets
if( raw == '\xcd\x80' and Arch.currentIsIntel()):
self.type = GadgetType.INT80
self.asmStr = 'int 0x80'
self.hexStr = '\\xcd\\x80'
self.addrList = addr_list
self.nbInstr = self.nbInstrREIL = 1
self.semantics = Semantics()
return
# Check for 'syscall' gadgets
elif( raw == '\x0f\x05' and Arch.currentIsIntel()):
self.type = GadgetType.SYSCALL
self.asmStr = 'syscall'
self.hexStr = '\\x0f\\x05'
self.addrList = addr_list
self.nbInstr = self.nbInstrREIL = 1
self.semantics = Semantics()
return
# Translate raw assembly into REIL
# Then compute the Graph and its semantics
try:
(irsb, ins) = Arch.currentArch.asmToREIL(raw)
except Arch.ArchException as e:
raise GadgetException(str(e))
try:
self.graph = REILtoGraph(irsb)
self.semantics = self.graph.getSemantics()
except GraphException as e:
raise GadgetException("(In {}) - ".format('; '.join(str(i) for i in ins)) + str(e))
self.type = GadgetType.REGULAR
# Possible addresses
self.addrList = addr_list
# String representations
self.asmStr = '; '.join(str(i) for i in ins)
self.hexStr = '\\x' + '\\x'.join("{:02x}".format(ord(c)) for c in raw)
# Length of the gadget
self.nbInstr = len(ins)
self.nbInstrREIL = len(irsb)
# List of modified registers
# And of memory-read accesses
self._modifiedRegs = []
self._memoryReads = []
for reg_num in list(set([reg.num for reg in self.semantics.registers.keys()])):
# Check if there is an empty semantics
if( not self.getSemantics(reg_num)):
#self.semantics.registers.pop(reg)
log("Gadget ({}) : empty semantics for {}"\
.format(self.asmStr, Arch.r2n(reg_num)))
self._modifiedRegs.append(reg_num)
continue
# Get modified reg
if ((SSAExpr(reg_num,0) != self.getSemantics(reg_num)[0].expr) ):
self._modifiedRegs.append(reg_num)
# Get memory reads
for pair in self.getSemantics(reg_num):
self._memoryReads += [m[0] for m in pair.expr.getMemAcc()]
self._modifiedRegs = list(set(self._modifiedRegs))
# SP Increment
if( self.type != GadgetType.REGULAR ):
self.spInc = None
else:
sp_num = Arch.spNum()
if( not sp_num in self.graph.lastMod ):
self.spInc = 0
else:
sp = SSAReg(sp_num, self.graph.lastMod[sp_num])
if( len(self.semantics.get(sp)) == 1 ):
(isInc, inc) = self.semantics.get(sp)[0].expr.isRegIncrement(sp_num)
if( isInc ):
self.spInc = inc
else:
self.spInc = None
else:
self.spInc = None
# Return type
self.retType = RetType.UNKNOWN
self.retValue = None
if( self.type == GadgetType.REGULAR ):
ip_num = Arch.n2r(Arch.currentArch.ip)
ip = SSAReg(ip_num, self.graph.lastMod[ip_num])
sp_num = Arch.n2r(Arch.currentArch.sp)
if( self.spInc != None ):
for p in self.semantics.get(ip):
if( p.cond.isTrue()):
if( isinstance(p.expr, MEMExpr)):
addr = p.expr.addr
(isInc, inc) = addr.isRegIncrement(sp_num)
# Normal ret if the final value of the IP is value that was in memory before the last modification of SP ( i.e final_IP = MEM[final_sp - size_of_a_register )
if( isInc and inc == (self.spInc - (Arch.currentArch.octets)) ):
self.retType = RetType.RET
self.retValue = p.expr
elif( isinstance(p.expr, SSAExpr )):
self.retValue = p.expr
# Try to detect gadgets ending by 'call'
if( ins[-1]._mnemonic[:4] == "call"):
self.retType = RetType.CALL
else:
self.retType = RetType.JMP
def __init__(self, msg):
self.msg = msg
log(msg)
def build(pair_list):
"""
Takes a list of pairs (addr, raw_asm) corresponding to
gagets (their address and their intructions as a byte string)
Fills the 'gadgets' and 'db' global structures ;)
"""
def sigint_handler(signal, frame):
global sigint
sigint = True
def timeout_handler(signum, frame):
global sigalarm
sigalarm = True
signal.alarm(0)
raise TimeOutException('Timeout')
global gadgets, db, sigint
gadgets = []
raw_to_gadget = dict()
sigint = False
original_sigint_handler = signal.getsignal(signal.SIGINT)
signal.signal(signal.SIGINT, sigint_handler)
signal.signal(signal.SIGALRM, timeout_handler)
info(string_bold("Creating gadget database\n"))
startTime = datetime.now()
success = i = 0
# Create the gadgets list
for (addr, raw) in pair_list:
charging_bar(len(pair_list) - 1, i, 30)
if (sigint):
break
if (raw in raw_to_gadget):
gadgets[raw_to_gadget[raw]].addrList.append(addr)
success += 1
else:
try:
signal.alarm(1)
gadget = Gadget([addr], raw)
signal.alarm(0)
success += 1
gadgets.append(gadget)
raw_to_gadget[raw] = len(gadgets) - 1
except (GadgetException, TimeOutException) as e:
signal.alarm(0)
if (isinstance(e, GadgetException)):
log("Gadget ({}) : ".format('\\x'+'\\x'\
.join("{:02x}".format(ord(c)) for c in raw)) + str(e))
i += 1
# Find syscalls
# TODO
# Getting time
cTime = datetime.now() - startTime
signal.signal(signal.SIGINT, original_sigint_handler)
if (sigint):
print("\n")
fatal(
"SIGINT ended the analysis prematurely, gadget database might be incomplete\n"
)
sigint = False
notify("Gadgets analyzed : " + str(len(pair_list)))
notify("Successfully translated : " + str(success))
notify("Computation time : " + str(cTime))
# Create the database
db = Database(gadgets)