result to online lookup can be ambiguous. use first item and note this

in disassembly

mythril/disassembler/disassembly.py

@@ -12,11 +12,11 @@ class Disassembly:
         self.addr_to_func = {}
         self.bytecode = code
 
-        signatures = Signatures(enable_online_lookkup=True)  # control if you want to have online sighash lookups
+        signatures = Signatures(enable_online_lookup=True)  # control if you want to have online sighash lookups
         try:
             signatures.open()  # open from default locations
         except FileNotFoundError:
-            logging.info("Missing function signature file. Resolving of function names from disabled.")
+            logging.info("Missing function signature file. Resolving of function names from signature file disabled.")
 
         # Parse jump table & resolve function names
 
@@ -25,7 +25,15 @@ class Disassembly:
         for i in jmptable_indices:
             func_hash = self.instruction_list[i]['argument']
             try:
-                func_name = signatures.get(func_hash)  # tries local cache, file and optional online lookup
+                # tries local cache, file and optional online lookup
+                # may return more than one function signature. since we cannot probe for the correct one we'll use the first
+                func_names = signatures.get(func_hash)
+                if len(func_names) > 1:
+                    # ambigious result
+                    func_name = "**ambiguous** %s"%func_names[0]  # return first hit but note that result was ambiguous
+                else:
+                    # only one item
+                    func_name = func_names[0]
             except KeyError:
                 func_name = "_function_" + func_hash
 

mythril/support/signatures.py

@@ -56,9 +56,9 @@ def add_signatures_from_file(file, sigs={}):
 
 class Signatures(object):
 
-    def __init__(self, enable_online_lookkup=True):
+    def __init__(self, enable_online_lookup=True):
         self.signatures = {}  # signatures in-mem cache
-        self.enable_online_lookup =enable_online_lookkup  # enable online funcsig resolving
+        self.enable_online_lookup =enable_online_lookup  # enable online funcsig resolving
 
     def open(self, path=None):
         if not path:
@@ -91,14 +91,17 @@ class Signatures(object):
         :return: list of function signatures
         """
         if not self.signatures.get(sighash) and self.enable_online_lookup:
-            self.signatures[sighash] = Signatures.lookup_online(sighash)  # might return multiple sigs
-        return self.signatures.get(sighash)
+            funcsigs = Signatures.lookup_online(sighash)  # might return multiple sigs
+            if funcsigs:
+                # only store if we get at least one result
+                self.signatures[sighash] = funcsigs
+        return self.signatures[sighash]  # raise keyerror
 
 
     @staticmethod
     def lookup_online(sighash):
         """
-        Lookup function signatures from 4bytes.directory.
+        Lookup function signatures from 4byte.directory.
         //tintinweb: the smart-contract-sanctuary project dumps contracts from etherscan.io and feeds them into
                      4bytes.directory.
                      https://github.com/tintinweb/smart-contract-sanctuary