Add new disassembler class

README.md

@@ -70,7 +70,7 @@ vm op=PUSH1 gas=b'20997' stack=[b'96'] depth=0 steps=1 inst=96 pushvalue=64 pc=b
 vm op=MSTORE gas=b'20994' stack=[b'96', b'64'] depth=0 steps=2 inst=82 pc=b'4'
 ```
 
-Do note however that the disassembly / debugging functionality is still quite bare-bones. For manual analysis & debugging I recommend using [remix](https://remix.ethereum.org/) and [etherscan](https://etherscan.io).
+Do note however that the instruction_list / debugging functionality is still quite bare-bones. For manual analysis & debugging I recommend using [remix](https://remix.ethereum.org/) and [etherscan](https://etherscan.io).
 
 #### Finding cross-references
 

disassembler/disassembly.py

@@ -0,0 +1,92 @@
+from mythril.ether import asm,evm,util
+from mythril.rpc.client import EthJsonRpc
+from ethereum import utils
+import binascii
+import sys
+import os
+import json
+
+
+class Block:
+
+    def __init__(self, code_index, start_addr, funcname):
+        self.code_index = code_index
+        self.funcname = funcname
+        self.xrefs = []
+
+
+    def update_length(self, num_instructions):
+        self.length = num_instructions
+
+
+
+class Disassembly:
+
+    def __init__(self, code):
+        self.instruction_list = asm.disassemble(util.safe_decode(code))
+        self.blocks = []
+        self.func_to_addr = {}
+        self.addr_to_func = []
+
+        # Parse jump table & resolve function names
+
+        script_dir = os.path.dirname(os.path.realpath(__file__))
+        signature_file = os.path.join(script_dir, 'signatures.json')
+
+        with open(signature_file) as f:
+            signatures = json.load(f)
+
+        jmptable_indices = asm.find_opcode_sequence(["PUSH4", "EQ"], self.instruction_list)
+
+        for i in jmptable_indices:
+            func_hash = self.instruction_list[i]['argument']
+            try:
+                func_name = signatures[func_hash]
+            except KeyError:
+                func_name = "UNK_" + func_hash
+
+            try:
+                offset = self.instruction_list[i+2]['argument']
+                jump_target = self.instruction_list[i]['address'] + int(offset, 16)
+
+                self.func_to_addr[func_name] = jump_target
+                self.addr_to_func[jump_target] = func_name
+            except:
+                continue
+
+        # Parse instructions into basic blocks
+
+        current_block = Block(0, 0, "prologue")
+
+        index = 0
+        blocklen = 0
+
+        for instruction in self.instruction_list:
+
+            blocklen += 1
+
+            if (instruction['opcode'] == "JUMPDEST"):
+
+                try:
+                    func_name = self.addr_to_func[instruction['address']]
+                except IndexError:
+                    func_name = "UNKNOWN_JUMPDEST"
+                
+                current_block.update_length(blocklen)
+                self.blocks.append(current_block)
+                current_block = Block(index, instruction['address'], func_name)
+                blocklen = 0
+
+            index += 1
+
+
+    def get_easm(self):
+
+        easm = ""
+
+        for block in self.blocks:
+            easm += str(self.instruction_list[block.code_index]['address']) + " --- " + block.funcname + "---\n"
+            
+            easm += asm.instruction_list_to_easm(self.instruction_list[block.code_index + 1:block.code_index + block.length])
+
+        return easm

myth

@@ -5,6 +5,7 @@
 """
 
 from mythril.ether import asm,evm,util
+from disassembler.disassembly import Disassembly
 from mythril.ether.contractstorage import get_persistent_storage
 from mythril.rpc.client import EthJsonRpc
 from ethereum import utils
@@ -78,11 +79,12 @@ if (args.disassemble):
         exitWithError("Disassembler: Provide the input bytecode via -c BYTECODE or --id ID")
 
     try:
-        disassembly = asm.disassemble(util.safe_decode(encoded_bytecode))
+        disassembly = Disassembly(encoded_bytecode)
+        # instruction_list = asm.disassemble(util.safe_decode(encoded_bytecode))
     except binascii.Error:
         exitWithError("Disassembler: Invalid code string.")
 
-    easm_text = asm.disassembly_to_easm(disassembly)
+    easm_text = disassembly.get_easm()
 
     if (args.outfile):
         util.string_to_file(args.outfile, easm_text)

mythril/ether/asm.py

@@ -2,30 +2,34 @@ import sys
 import re
 import codecs
 from ethereum import opcodes
+from mythril.ether import util
 
 
 regex_PUSH = re.compile('^PUSH(\d*)$')
 
 
-def disassembly_to_easm(disassembly):
+def instruction_list_to_easm(instruction_list):
     easm = ""
 
-    for instruction in disassembly:
-        easm += instruction['opcode']
+    # print(instruction_list)
+
+    for instruction in instruction_list:
+
+        easm += str(instruction['address']) + " " + instruction['opcode']
 
         if 'argument' in instruction:
-            easm += " 0x" + codecs.decode(instruction['argument'], 'utf-8')
+            easm += " " + instruction['argument']
 
         easm += "\n"
 
     return easm
 
 
-def easm_to_disassembly(easm):
+def easm_to_instruction_list(easm):
 
     regex_CODELINE = re.compile('^([A-Z0-9]+)(?:\s+([0-9a-fA-Fx]+))?$')
 
-    disassembly = []
+    instruction_list = []
 
     codelines = easm.split('\n')
 
@@ -44,9 +48,9 @@ def easm_to_disassembly(easm):
         if m.group(2):
             instruction['argument'] = m.group(2)[2:]
 
-        disassembly.append(instruction)
+        instruction_list.append(instruction)
 
-    return disassembly
+    return instruction_list
 
 
 def get_opcode_from_name(name):
@@ -60,20 +64,20 @@ def get_opcode_from_name(name):
     raise RuntimeError("Unknown opcode")
 
 
-def find_opcode_sequence(pattern, disassembly):
+def find_opcode_sequence(pattern, instruction_list):
     match_indexes = []
 
     pattern_length = len(pattern)
 
-    for i in range(0, len(disassembly) - pattern_length):
+    for i in range(0, len(instruction_list) - pattern_length):
 
-        if disassembly[i]['opcode'] == pattern[0]:
+        if instruction_list[i]['opcode'] == pattern[0]:
 
             matched = True
 
             for j in range(1, len(pattern)):
 
-                if not (disassembly[i + j]['opcode'] == pattern[j]):
+                if not (instruction_list[i + j]['opcode'] == pattern[j]):
                     matched = False
                     break
 
@@ -85,24 +89,26 @@ def find_opcode_sequence(pattern, disassembly):
 
 def disassemble(bytecode):
 
-    disassembly = []
-    i = 0
+    instruction_list = []
+    addr = 0
 
-    while i < len(bytecode):
+    while addr < len(bytecode):
 
         instruction = {}
 
+        instruction['address'] = addr
+
         try:
             if (sys.version_info > (3, 0)):
-                opcode = opcodes.opcodes[bytecode[i]]
+                opcode = opcodes.opcodes[bytecode[addr]]
             else:
-                 opcode = opcodes.opcodes[ord(bytecode[i])]
+                opcode = opcodes.opcodes[ord(bytecode[addr])]
 
         except KeyError:
 
             # invalid opcode
-            disassembly.append({'opcode': "INVALID"})
-            i += 1
+            instruction_list.append({'address': addr, 'opcode': "INVALID"})
+            addr += 1
             continue
 
         instruction['opcode'] = opcode[0]
@@ -110,22 +116,22 @@ def disassemble(bytecode):
         m = re.search(regex_PUSH, opcode[0])
 
         if m:
-            argument = bytecode[i+1:i+1+int(m.group(1))]
-            instruction['argument'] = codecs.encode(argument, "hex_codec")
-            i += int(m.group(1))
+            argument = bytecode[addr+1:addr+1+int(m.group(1))]
+            instruction['argument'] = "0x" + argument.hex()
+            addr += int(m.group(1))
 
-        disassembly.append(instruction)
+        instruction_list.append(instruction)
 
-        i += 1
+        addr += 1
 
-    return disassembly
+    return instruction_list
 
 
-def assemble(disassembly):
+def assemble(instruction_list):
 
     bytecode = b""
 
-    for instruction in disassembly:
+    for instruction in instruction_list:
 
         try:
             opcode = get_opcode_from_name(instruction['opcode'])
@@ -136,6 +142,6 @@ def assemble(disassembly):
 
         if 'argument' in instruction:
 
-            bytecode += codecs.decode(instruction['argument'], 'hex_codec')
+            bytecode += util.safe_decode(instruction['argument'])
 
     return bytecode

mythril/ether/ethcontract.py

@@ -13,30 +13,30 @@ class ETHContract(persistent.Persistent):
 
     def get_xrefs(self):
 
-        disassembly = asm.disassemble(util.safe_decode(self.code))
+        instruction_list = asm.disassemble(util.safe_decode(self.code))
 
         xrefs = []
 
-        for instruction in disassembly:
+        for instruction in instruction_list:
             if instruction['opcode'] == "PUSH20":
                 if instruction['argument']:
-                    addr = instruction['argument'].decode("utf-8")
+                    addr = instruction['argument']
 
-                    if (re.match(r'^[a-zA-Z0-9]{40}$', addr) and addr != "ffffffffffffffffffffffffffffffffffffffff"):
+                    if (re.match(r'^0x[a-zA-Z0-9]{40}$', addr) and addr != "0xffffffffffffffffffffffffffffffffffffffff"):
                         if addr not in xrefs:
                             xrefs.append(addr)
 
         return xrefs
 
 
-    def get_disassembly(self):
+    def get_instruction_list(self):
 
         return asm.disassemble(util.safe_decode(self.code))
 
 
     def get_easm(self):
 
-        return asm.disassembly_to_easm(asm.disassemble(util.safe_decode(self.code)))
+        return asm.instruction_list_to_easm(asm.disassemble(util.safe_decode(self.code)))
 
 
     def matches_expression(self, expression):

tests/ethcontract_test.py

@@ -7,15 +7,15 @@ class ETHContractTestCase(unittest.TestCase):
     def setUp(self):
         self.code = "0x60606040525b603c5b60006010603e565b9050593681016040523660008237602060003683856040603f5a0204f41560545760206000f35bfe5b50565b005b73c3b2ae46792547a96b9f84405e36d0e07edcd05c5b905600a165627a7a7230582062a884f947232ada573f95940cce9c8bfb7e4e14e21df5af4e884941afb55e590029"
 
-class GetDisassemblyTestCase(ETHContractTestCase):
+class Getinstruction_listTestCase(ETHContractTestCase):
 
     def runTest(self):
 
         contract = ETHContract(self.code)
 
-        disassembly = contract.get_disassembly()
+        instruction_list = contract.get_instruction_list()
 
-        self.assertEqual(len(disassembly), 71, 'Error disassembling code using ETHContract.get_disassembly()')
+        self.assertEqual(len(instruction_list), 71, 'Error disassembling code using ETHContract.get_instruction_list()')
 
 class GetEASMTestCase(ETHContractTestCase):
 
@@ -23,9 +23,9 @@ class GetEASMTestCase(ETHContractTestCase):
 
         contract = ETHContract(self.code)
 
-        disassembly = contract.get_easm()
+        instruction_list = contract.get_easm()
 
-        self.assertTrue("PUSH1 0x60" in disassembly,'Error obtaining EASM code through ETHContract.get_easm()')
+        self.assertTrue("PUSH1 0x60" in instruction_list,'Error obtaining EASM code through ETHContract.get_easm()')
 
 class MatchesExpressionTestCase(ETHContractTestCase):
 
@@ -44,4 +44,4 @@ class GetXrefsTestCase(ETHContractTestCase):
 
         xrefs = contract.get_xrefs()
 
-        self.assertEqual(xrefs[0], "c3b2ae46792547a96b9f84405e36d0e07edcd05c", 'Error getting xrefs from contract')
+        self.assertEqual(xrefs[0], "0xc3b2ae46792547a96b9f84405e36d0e07edcd05c", 'Error getting xrefs from contract')