Merge pull request #375 from crytic/dev-reentrancies

Improvements on reentrancies detectors

scripts/tests_generate_expected_json_4.sh

@@ -31,6 +31,7 @@ generate_expected_json(){
 #generate_expected_json tests/pragma.0.4.24.sol "pragma"
 #generate_expected_json tests/old_solc.sol.json "solc-version"
 #generate_expected_json tests/reentrancy.sol "reentrancy-eth"
+generate_expected_json tests/reentrancy.sol "reentrancy-unlimited-gas"
 #generate_expected_json tests/uninitialized_storage_pointer.sol "uninitialized-storage"
 #generate_expected_json tests/tx_origin.sol "tx-origin"
 #generate_expected_json tests/unused_state.sol "unused-state"

scripts/travis_test_etherscan.sh

@@ -18,7 +18,7 @@ fi
 
 slither rinkeby:0xFe05820C5A92D9bc906D4A46F662dbeba794d3b7 --solc "./solc-0.4.25"
 
-if [ $? -ne 70 ]
+if [ $? -ne 71 ]
 then
     echo "Etherscan test failed"
     exit -1

slither/detectors/all_detectors.py

@@ -11,6 +11,8 @@ from .functions.suicidal import Suicidal
 from .reentrancy.reentrancy_benign import ReentrancyBenign
 from .reentrancy.reentrancy_read_before_write import ReentrancyReadBeforeWritten
 from .reentrancy.reentrancy_eth import ReentrancyEth
+from .reentrancy.reentrancy_no_gas import ReentrancyNoGas
+from .reentrancy.reentrancy_events import ReentrancyEvent
 from .variables.unused_state_variables import UnusedStateVars
 from .variables.possible_const_state_variables import ConstCandidateStateVars
 from .statements.tx_origin import TxOrigin

slither/detectors/reentrancy/reentrancy.py

@@ -9,20 +9,21 @@ from slither.core.cfg.node import NodeType
 from slither.core.declarations import Function
 from slither.core.expressions import UnaryOperation, UnaryOperationType
 from slither.detectors.abstract_detector import AbstractDetector
-from slither.slithir.operations import Call
+from slither.slithir.operations import Call, EventCall
 
 
 def union_dict(d1, d2):
     d3 = {k: d1.get(k, set()) | d2.get(k, set()) for k in set(list(d1.keys()) + list(d2.keys()))}
     return d3
 
+
 def dict_are_equal(d1, d2):
     if set(list(d1.keys())) != set(list(d2.keys())):
         return False
     return all(set(d1[k]) == set(d2[k]) for k in d1.keys())
 
-class Reentrancy(AbstractDetector):
 
+class Reentrancy(AbstractDetector):
     KEY = 'REENTRANCY'
 
     def _can_callback(self, irs):
@@ -49,9 +50,6 @@ class Reentrancy(AbstractDetector):
         for ir in irs:
             if isinstance(ir, Call) and ir.can_send_eth():
                 return True
-            # if isinstance(ir, (HighLevelCall, LowLevelCall, Transfer, Send)):
-            #     if ir.call_value:
-            #         return True
         return False
 
     def _filter_if(self, node):
@@ -65,8 +63,8 @@ class Reentrancy(AbstractDetector):
 
             This will work only on naive implementation
         """
-        return isinstance(node.expression, UnaryOperation)\
+        return isinstance(node.expression, UnaryOperation) \
-            and node.expression.type == UnaryOperationType.BANG
+               and node.expression.type == UnaryOperationType.BANG
 
     def _explore(self, node, visited, skip_father=None):
         """
@@ -89,29 +87,37 @@ class Reentrancy(AbstractDetector):
         # calls returns the list of calls that can callback
         # read returns the variable read
         # read_prior_calls returns the variable read prior a call
-        fathers_context = {'send_eth':set(), 'calls':set(), 'read':set(), 'read_prior_calls':{}}
+        fathers_context = {'send_eth': set(), 'calls': set(), 'read': set(), 'read_prior_calls': {}, 'events': set()}
 
         for father in node.fathers:
             if self.KEY in father.context:
-                fathers_context['send_eth'] |= set([s for s in father.context[self.KEY]['send_eth'] if s!=skip_father])
+                fathers_context['send_eth'] |= set(
-                fathers_context['calls'] |= set([c for c in father.context[self.KEY]['calls'] if c!=skip_father])
+                    [s for s in father.context[self.KEY]['send_eth'] if s != skip_father])
+                fathers_context['calls'] |= set([c for c in father.context[self.KEY]['calls'] if c != skip_father])
                 fathers_context['read'] |= set(father.context[self.KEY]['read'])
-                fathers_context['read_prior_calls'] = union_dict(fathers_context['read_prior_calls'], father.context[self.KEY]['read_prior_calls'])
+                fathers_context['read_prior_calls'] = union_dict(fathers_context['read_prior_calls'],
+                                                                 father.context[self.KEY]['read_prior_calls'])
+                fathers_context['events'] |= set(father.context[self.KEY]['events'])
 
         # Exclude path that dont bring further information
         if node in self.visited_all_paths:
-            if all(call in self.visited_all_paths[node]['calls'] for call in fathers_context['calls']):
+            if fathers_context['calls'].issubset(self.visited_all_paths[node]['calls']):
-                if all(send in self.visited_all_paths[node]['send_eth'] for send in fathers_context['send_eth']):
+                if fathers_context['send_eth'].issubset(self.visited_all_paths[node]['send_eth']):
-                    if all(read in self.visited_all_paths[node]['read'] for read in fathers_context['read']):
+                    if fathers_context['read'].issubset(self.visited_all_paths[node]['read']):
-                        if dict_are_equal(self.visited_all_paths[node]['read_prior_calls'], fathers_context['read_prior_calls']):
+                        if dict_are_equal(self.visited_all_paths[node]['read_prior_calls'],
-                            return
+                                          fathers_context['read_prior_calls']):
+                            if fathers_context['events'].issubset(self.visited_all_paths[node]['events']):
+                                return
         else:
-            self.visited_all_paths[node] = {'send_eth':set(), 'calls':set(), 'read':set(), 'read_prior_calls':{}}
+            self.visited_all_paths[node] = {'send_eth': set(), 'calls': set(), 'read': set(),
+                                            'read_prior_calls': {}, 'events': set()}
 
-        self.visited_all_paths[node]['send_eth'] = set(self.visited_all_paths[node]['send_eth'] | fathers_context['send_eth'])
+        self.visited_all_paths[node]['send_eth'] |= fathers_context['send_eth']
-        self.visited_all_paths[node]['calls'] = set(self.visited_all_paths[node]['calls'] | fathers_context['calls'])
+        self.visited_all_paths[node]['calls'] |=  fathers_context['calls']
-        self.visited_all_paths[node]['read'] = set(self.visited_all_paths[node]['read'] | fathers_context['read'])
+        self.visited_all_paths[node]['read'] |= fathers_context['read']
-        self.visited_all_paths[node]['read_prior_calls'] = union_dict(self.visited_all_paths[node]['read_prior_calls'], fathers_context['read_prior_calls'])
+        self.visited_all_paths[node]['read_prior_calls'] = union_dict(self.visited_all_paths[node]['read_prior_calls'],
+                                                                      fathers_context['read_prior_calls'])
+        self.visited_all_paths[node]['events'] |= fathers_context['events']
 
         node.context[self.KEY] = fathers_context
 
@@ -131,13 +137,17 @@ class Reentrancy(AbstractDetector):
         contains_call = False
         node.context[self.KEY]['written'] = set(state_vars_written)
         if self._can_callback(node.irs + slithir_operations):
-            node.context[self.KEY]['calls'] = set(node.context[self.KEY]['calls'] | {node})
+            node.context[self.KEY]['calls'] |= {node}
-            node.context[self.KEY]['read_prior_calls'][node] = set(node.context[self.KEY]['read_prior_calls'].get(node, set()) | node.context[self.KEY]['read'] |state_vars_read)
+            node.context[self.KEY]['read_prior_calls'][node] = set(
+                node.context[self.KEY]['read_prior_calls'].get(node, set()) | node.context[self.KEY][
+                    'read'] | state_vars_read)
             contains_call = True
         if self._can_send_eth(node.irs + slithir_operations):
-            node.context[self.KEY]['send_eth'] = set(node.context[self.KEY]['send_eth'] | {node})
+            node.context[self.KEY]['send_eth'] |= {node}
+
+        node.context[self.KEY]['read'] |= state_vars_read
 
-        node.context[self.KEY]['read'] = set(node.context[self.KEY]['read'] | state_vars_read)
+        node.context[self.KEY]['events'] |= set([ir for ir in node.irs if isinstance(ir, EventCall)])
 
         sons = node.sons
         if contains_call and node.type in [NodeType.IF, NodeType.IFLOOP]:

slither/detectors/reentrancy/reentrancy_events.py

@@ -0,0 +1,112 @@
+""""
+    Re-entrancy detection
+
+    Based on heuristics, it may lead to FP and FN
+    Iterate over all the nodes of the graph until reaching a fixpoint
+"""
+from slither.detectors.abstract_detector import DetectorClassification
+
+
+from .reentrancy import Reentrancy
+class ReentrancyEvent(Reentrancy):
+    ARGUMENT = 'reentrancy-events'
+    HELP = 'Reentrancy vulnerabilities leading to out-of-order Events'
+    IMPACT = DetectorClassification.LOW
+    CONFIDENCE = DetectorClassification.MEDIUM
+
+    WIKI = 'https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-4'
+
+    WIKI_TITLE = 'Reentrancy vulnerabilities'
+    WIKI_DESCRIPTION = '''
+Detection of the [re-entrancy bug](https://github.com/trailofbits/not-so-smart-contracts/tree/master/reentrancy).
+Only report reentrancies leading to out-of-order Events'''
+    WIKI_EXPLOIT_SCENARIO = '''
+```solidity
+    function bug(Called d){
+        counter += 1;
+        d.f();
+        emit Counter(counter);
+    }
+```
+
+If `d.()` reenters, the `Counter` events will be showed in an incorrect order, which might lead to issues for third-parties.'''
+
+
+    WIKI_RECOMMENDATION = 'Apply the [check-effects-interactions pattern](http://solidity.readthedocs.io/en/v0.4.21/security-considerations.html#re-entrancy).'
+
+    STANDARD_JSON = False
+
+    def find_reentrancies(self):
+        result = {}
+        for contract in self.contracts:
+            for f in contract.functions_and_modifiers_declared:
+                for node in f.nodes:
+                    # dead code
+                    if not self.KEY in node.context:
+                        continue
+                    if node.context[self.KEY]['calls']:
+                        if not any(n != node for n in node.context[self.KEY]['calls']):
+                            continue
+
+                        # calls are ordered
+                        finding_key = (node.function,
+                                       tuple(sorted(list(node.context[self.KEY]['calls']), key=lambda x: x.node_id)),
+                                       tuple(sorted(list(node.context[self.KEY]['send_eth']), key=lambda x: x.node_id)))
+                        finding_vars = list(node.context[self.KEY]['events'])
+                        if finding_vars:
+                            if finding_key not in result:
+                                result[finding_key] = set()
+                            result[finding_key] = set(result[finding_key] | set(finding_vars))
+        return result
+
+    def _detect(self):
+        """
+        """
+        super()._detect()
+
+        reentrancies = self.find_reentrancies()
+
+        results = []
+
+        result_sorted = sorted(list(reentrancies.items()), key=lambda x:x[0][0].name)
+        for (func, calls, send_eth), events in result_sorted:
+            calls = sorted(list(set(calls)), key=lambda x: x.node_id)
+            send_eth = sorted(list(set(send_eth)), key=lambda x: x.node_id)
+
+            info = ['Reentrancy in ', func, ':\n']
+            info += ['\tExternal calls:\n']
+            for call_info in calls:
+                info += ['\t- ' , call_info, '\n']
+            if calls != send_eth and send_eth:
+                info += ['\tExternal calls sending eth:\n']
+                for call_info in send_eth:
+                    info += ['\t- ', call_info, '\n']
+            info += ['\tEvent emitted after the call(s):\n']
+            for event in sorted(events, key=lambda x: x.node.node_id):
+                info += ['\t- ', event.node, '\n']
+
+            # Create our JSON result
+            res = self.generate_result(info)
+
+            # Add the function with the re-entrancy first
+            res.add(func)
+
+            # Add all underlying calls in the function which are potentially problematic.
+            for call_info in calls:
+                res.add(call_info, {
+                    "underlying_type": "external_calls"
+                })
+
+            #
+
+            # If the calls are not the same ones that send eth, add the eth sending nodes.
+            if calls != send_eth:
+                for call_info in send_eth:
+                    res.add(call_info, {
+                        "underlying_type": "external_calls_sending_eth"
+                    })
+
+            # Append our result
+            results.append(res)
+
+        return results

slither/detectors/reentrancy/reentrancy_no_gas.py

@@ -0,0 +1,138 @@
+""""
+    Re-entrancy detection
+
+    Based on heuristics, it may lead to FP and FN
+    Iterate over all the nodes of the graph until reaching a fixpoint
+"""
+from slither.core.variables.variable import Variable
+from slither.detectors.abstract_detector import DetectorClassification
+from slither.slithir.operations import Send, Transfer, EventCall
+from .reentrancy import Reentrancy
+
+
+class ReentrancyNoGas(Reentrancy):
+    KEY = 'REENTRANCY_NO_GAS'
+
+    ARGUMENT = 'reentrancy-unlimited-gas'
+    HELP = 'Reentrancy vulnerabilities through send and transfer'
+    IMPACT = DetectorClassification.INFORMATIONAL
+    CONFIDENCE = DetectorClassification.MEDIUM
+
+    WIKI = 'https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-3'
+
+    WIKI_TITLE = 'Reentrancy vulnerabilities'
+    WIKI_DESCRIPTION = '''
+Detection of the [re-entrancy bug](https://github.com/trailofbits/not-so-smart-contracts/tree/master/reentrancy).
+Only report reentrancy that are based on `transfer` or `send`.'''
+    WIKI_EXPLOIT_SCENARIO = '''
+```solidity
+    function callme(){
+        msg.sender.transfer(balances[msg.sender]):
+        balances[msg.sender] = 0;
+    }   
+```
+
+`send` and `transfer` does not protect from reentrancies in case of gas-price change.'''
+
+    WIKI_RECOMMENDATION = 'Apply the [check-effects-interactions pattern](http://solidity.readthedocs.io/en/v0.4.21/security-considerations.html#re-entrancy).'
+
+    def _can_callback(self, irs):
+        """
+        Same as Reentrancy, but also consider Send and Transfer
+
+        """
+        return any((isinstance(ir, (Send, Transfer)) for ir in irs))
+
+    STANDARD_JSON = False
+
+    def find_reentrancies(self):
+        result = {}
+        for contract in self.contracts:
+            for f in contract.functions_and_modifiers_declared:
+                for node in f.nodes:
+                    # dead code
+                    if not self.KEY in node.context:
+                        continue
+                    if node.context[self.KEY]['calls']:
+                        if not any(n != node for n in node.context[self.KEY]['calls']):
+                            continue
+
+                        # calls are ordered
+                        finding_key = (node.function,
+                                       tuple(sorted(list(node.context[self.KEY]['calls']), key=lambda x: x.node_id)),
+                                       tuple(sorted(list(node.context[self.KEY]['send_eth']), key=lambda x: x.node_id)))
+                        finding_vars = [(v, node) for v in node.context[self.KEY]['written']]
+                        finding_vars += [(e, e.node) for e in node.context[self.KEY]['events']]
+                        if finding_vars:
+                            if finding_key not in result:
+                                result[finding_key] = set()
+                            result[finding_key] = set(result[finding_key] | set(finding_vars))
+        return result
+
+    def _detect(self):
+        """
+        """
+
+        super()._detect()
+        reentrancies = self.find_reentrancies()
+
+        results = []
+
+        result_sorted = sorted(list(reentrancies.items()), key=lambda x: x[0][0].name)
+        for (func, calls, send_eth), varsWrittenOrEvent in result_sorted:
+            calls = sorted(list(set(calls)), key=lambda x: x.node_id)
+            send_eth = sorted(list(set(send_eth)), key=lambda x: x.node_id)
+            info = ['Reentrancy in ', func, ':\n']
+
+            info += ['\tExternal calls:\n']
+            for call_info in calls:
+                info += ['\t- ', call_info, '\n']
+            if calls != send_eth and send_eth:
+                info += ['\tExternal calls sending eth:\n']
+                for call_info in send_eth:
+                    info += ['\t- ', call_info, '\n']
+
+            varsWritten = [(v, node) for (v, node) in varsWrittenOrEvent if isinstance(v, Variable)]
+            if varsWritten:
+                info += ['\tState variables written after the call(s):\n']
+                for (v, node) in sorted(varsWritten, key=lambda x: (x[0].name, x[1].node_id)):
+                    info += ['\t- ', v, ' in ', node, '\n']
+
+            events = [(e, node) for (e, node) in varsWrittenOrEvent if isinstance(e, EventCall)]
+            if events:
+                info += ['\tEvent emitted after the call(s):\n']
+                for (_, node) in sorted(events, key=lambda x: x[1].node_id):
+                    info += ['\t- ', node, '\n']
+
+            # Create our JSON result
+            res = self.generate_result(info)
+
+            # Add the function with the re-entrancy first
+            res.add(func)
+
+            # Add all underlying calls in the function which are potentially problematic.
+            for call_info in calls:
+                res.add(call_info, {
+                    "underlying_type": "external_calls"
+                })
+
+            #
+
+            # If the calls are not the same ones that send eth, add the eth sending nodes.
+            if calls != send_eth:
+                for call_info in send_eth:
+                    res.add(call_info, {
+                        "underlying_type": "external_calls_sending_eth"
+                    })
+
+            # Add all variables written via nodes which write them.
+            for (v, node) in varsWritten:
+                res.add(node, {
+                    "underlying_type": "variables_written",
+                    "variable_name": v.name
+                })
+
+            # Append our result
+            results.append(res)
+
+        return results

tests/expected_json/reentrancy.reentrancy-unlimited-gas.json

@@ -0,0 +1,410 @@
+{
+  "success": true,
+  "error": null,
+  "results": {
+    "detectors": [
+      {
+        "elements": [
+          {
+            "type": "function",
+            "name": "withdrawBalance_fixed_2",
+            "source_mapping": {
+              "start": 951,
+              "length": 386,
+              "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_relative": "tests/reentrancy.sol",
+              "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_short": "tests/reentrancy.sol",
+              "is_dependency": false,
+              "lines": [
+                33,
+                34,
+                35,
+                36,
+                37,
+                38,
+                39,
+                40
+              ],
+              "starting_column": 5,
+              "ending_column": 6
+            },
+            "type_specific_fields": {
+              "parent": {
+                "type": "contract",
+                "name": "Reentrancy",
+                "source_mapping": {
+                  "start": 26,
+                  "length": 2334,
+                  "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_relative": "tests/reentrancy.sol",
+                  "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_short": "tests/reentrancy.sol",
+                  "is_dependency": false,
+                  "lines": [
+                    3,
+                    4,
+                    5,
+                    6,
+                    7,
+                    8,
+                    9,
+                    10,
+                    11,
+                    12,
+                    13,
+                    14,
+                    15,
+                    16,
+                    17,
+                    18,
+                    19,
+                    20,
+                    21,
+                    22,
+                    23,
+                    24,
+                    25,
+                    26,
+                    27,
+                    28,
+                    29,
+                    30,
+                    31,
+                    32,
+                    33,
+                    34,
+                    35,
+                    36,
+                    37,
+                    38,
+                    39,
+                    40,
+                    41,
+                    42,
+                    43,
+                    44,
+                    45,
+                    46,
+                    47,
+                    48,
+                    49,
+                    50,
+                    51,
+                    52,
+                    53,
+                    54,
+                    55,
+                    56,
+                    57,
+                    58,
+                    59,
+                    60,
+                    61,
+                    62,
+                    63,
+                    64,
+                    65,
+                    66,
+                    67,
+                    68,
+                    69,
+                    70,
+                    71,
+                    72
+                  ],
+                  "starting_column": 1,
+                  "ending_column": 2
+                }
+              },
+              "signature": "withdrawBalance_fixed_2()"
+            }
+          },
+          {
+            "type": "node",
+            "name": "msg.sender.transfer(userBalance[msg.sender])",
+            "source_mapping": {
+              "start": 1249,
+              "length": 44,
+              "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_relative": "tests/reentrancy.sol",
+              "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_short": "tests/reentrancy.sol",
+              "is_dependency": false,
+              "lines": [
+                38
+              ],
+              "starting_column": 9,
+              "ending_column": 53
+            },
+            "type_specific_fields": {
+              "parent": {
+                "type": "function",
+                "name": "withdrawBalance_fixed_2",
+                "source_mapping": {
+                  "start": 951,
+                  "length": 386,
+                  "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_relative": "tests/reentrancy.sol",
+                  "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_short": "tests/reentrancy.sol",
+                  "is_dependency": false,
+                  "lines": [
+                    33,
+                    34,
+                    35,
+                    36,
+                    37,
+                    38,
+                    39,
+                    40
+                  ],
+                  "starting_column": 5,
+                  "ending_column": 6
+                },
+                "type_specific_fields": {
+                  "parent": {
+                    "type": "contract",
+                    "name": "Reentrancy",
+                    "source_mapping": {
+                      "start": 26,
+                      "length": 2334,
+                      "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                      "filename_relative": "tests/reentrancy.sol",
+                      "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                      "filename_short": "tests/reentrancy.sol",
+                      "is_dependency": false,
+                      "lines": [
+                        3,
+                        4,
+                        5,
+                        6,
+                        7,
+                        8,
+                        9,
+                        10,
+                        11,
+                        12,
+                        13,
+                        14,
+                        15,
+                        16,
+                        17,
+                        18,
+                        19,
+                        20,
+                        21,
+                        22,
+                        23,
+                        24,
+                        25,
+                        26,
+                        27,
+                        28,
+                        29,
+                        30,
+                        31,
+                        32,
+                        33,
+                        34,
+                        35,
+                        36,
+                        37,
+                        38,
+                        39,
+                        40,
+                        41,
+                        42,
+                        43,
+                        44,
+                        45,
+                        46,
+                        47,
+                        48,
+                        49,
+                        50,
+                        51,
+                        52,
+                        53,
+                        54,
+                        55,
+                        56,
+                        57,
+                        58,
+                        59,
+                        60,
+                        61,
+                        62,
+                        63,
+                        64,
+                        65,
+                        66,
+                        67,
+                        68,
+                        69,
+                        70,
+                        71,
+                        72
+                      ],
+                      "starting_column": 1,
+                      "ending_column": 2
+                    }
+                  },
+                  "signature": "withdrawBalance_fixed_2()"
+                }
+              }
+            },
+            "additional_fields": {
+              "underlying_type": "external_calls"
+            }
+          },
+          {
+            "type": "node",
+            "name": "userBalance[msg.sender] = 0",
+            "source_mapping": {
+              "start": 1303,
+              "length": 27,
+              "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_relative": "tests/reentrancy.sol",
+              "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+              "filename_short": "tests/reentrancy.sol",
+              "is_dependency": false,
+              "lines": [
+                39
+              ],
+              "starting_column": 9,
+              "ending_column": 36
+            },
+            "type_specific_fields": {
+              "parent": {
+                "type": "function",
+                "name": "withdrawBalance_fixed_2",
+                "source_mapping": {
+                  "start": 951,
+                  "length": 386,
+                  "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_relative": "tests/reentrancy.sol",
+                  "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                  "filename_short": "tests/reentrancy.sol",
+                  "is_dependency": false,
+                  "lines": [
+                    33,
+                    34,
+                    35,
+                    36,
+                    37,
+                    38,
+                    39,
+                    40
+                  ],
+                  "starting_column": 5,
+                  "ending_column": 6
+                },
+                "type_specific_fields": {
+                  "parent": {
+                    "type": "contract",
+                    "name": "Reentrancy",
+                    "source_mapping": {
+                      "start": 26,
+                      "length": 2334,
+                      "filename_used": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                      "filename_relative": "tests/reentrancy.sol",
+                      "filename_absolute": "/home/travis/build/crytic/slither/tests/reentrancy.sol",
+                      "filename_short": "tests/reentrancy.sol",
+                      "is_dependency": false,
+                      "lines": [
+                        3,
+                        4,
+                        5,
+                        6,
+                        7,
+                        8,
+                        9,
+                        10,
+                        11,
+                        12,
+                        13,
+                        14,
+                        15,
+                        16,
+                        17,
+                        18,
+                        19,
+                        20,
+                        21,
+                        22,
+                        23,
+                        24,
+                        25,
+                        26,
+                        27,
+                        28,
+                        29,
+                        30,
+                        31,
+                        32,
+                        33,
+                        34,
+                        35,
+                        36,
+                        37,
+                        38,
+                        39,
+                        40,
+                        41,
+                        42,
+                        43,
+                        44,
+                        45,
+                        46,
+                        47,
+                        48,
+                        49,
+                        50,
+                        51,
+                        52,
+                        53,
+                        54,
+                        55,
+                        56,
+                        57,
+                        58,
+                        59,
+                        60,
+                        61,
+                        62,
+                        63,
+                        64,
+                        65,
+                        66,
+                        67,
+                        68,
+                        69,
+                        70,
+                        71,
+                        72
+                      ],
+                      "starting_column": 1,
+                      "ending_column": 2
+                    }
+                  },
+                  "signature": "withdrawBalance_fixed_2()"
+                }
+              }
+            },
+            "additional_fields": {
+              "underlying_type": "variables_written",
+              "variable_name": "userBalance"
+            }
+          }
+        ],
+        "description": "Reentrancy in Reentrancy.withdrawBalance_fixed_2() (tests/reentrancy.sol#33-40):\n\tExternal calls:\n\t- msg.sender.transfer(userBalance[msg.sender]) (tests/reentrancy.sol#38)\n\tState variables written after the call(s):\n\t- Reentrancy.userBalance (tests/reentrancy.sol#4) in userBalance[msg.sender] = 0 (tests/reentrancy.sol#39)\n",
+        "markdown": "Reentrancy in [Reentrancy.withdrawBalance_fixed_2()](tests/reentrancy.sol#L33-L40):\n\tExternal calls:\n\t- [msg.sender.transfer(userBalance[msg.sender])](tests/reentrancy.sol#L38)\n\tState variables written after the call(s):\n\t- [Reentrancy.userBalance](tests/reentrancy.sol#L4) in [userBalance[msg.sender] = 0](tests/reentrancy.sol#L39)\n",
+        "id": "ff12b17dedf35fcd1f5b1286653a53430009f3689c46c06c1aba1f2d4b17d713",
+        "check": "reentrancy-unlimited-gas",
+        "impact": "Informational",
+        "confidence": "Medium"
+      }
+    ]
+  }
+}

tests/expected_json/reentrancy.reentrancy-unlimited-gas.txt

@@ -0,0 +1,8 @@
+
+Reentrancy in Reentrancy.withdrawBalance_fixed_2() (tests/reentrancy.sol#33-40):
+	External calls:
+	- msg.sender.transfer(userBalance[msg.sender]) (tests/reentrancy.sol#38)
+	State variables written after the call(s):
+	- Reentrancy.userBalance (tests/reentrancy.sol#4) in userBalance[msg.sender] = 0 (tests/reentrancy.sol#39)
+Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#reentrancy-vulnerabilities-3
+tests/reentrancy.sol analyzed (1 contracts with 1 detectors), 1 result(s) found

tests/expected_json/right_to_left_override.rtlo.txt

@@ -3,3 +3,4 @@ tests/right_to_left_override.sol contains a unicode right-to-left-override chara
 	- b'        test1(/*A\xe2\x80\xae/*B*/2 , 1/*\xe2\x80\xad'
 Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#right-to-left-override-character
 tests/right_to_left_override.sol analyzed (1 contracts with 1 detectors), 1 result(s) found
+INFO:Slither:/home/travis/build/crytic/slither/scripts/../tests/expected_json/right_to_left_override.rtlo.json exists already, the overwrite is prevented

tests/reentrancy.sol

@@ -70,3 +70,21 @@ contract Reentrancy {
     }   
 
 }
+
+
+contract Called{
+    function f() public;
+}
+
+contract ReentrancyEvent {
+
+    event E();
+
+    function test(Called c) public{
+
+        c.f();
+        emit E();
+
+    }
+}
+