Handlde null signatures and sources

Author: merendamattia

src/main/java/it/unipr/crosschain/checker/AccessControlIncompletenessChecker.java

@@ -1,5 +1,6 @@
 package it.unipr.crosschain.checker;
 
+import it.unipr.analysis.contract.Signature;
 import it.unipr.analysis.contract.SmartContract;
 import it.unipr.cfg.*;
 import it.unipr.crosschain.taint.RelationalTaintAbstractDomain;
@@ -252,7 +253,11 @@ private void reportVulnerability(CheckToolWithAnalysisResults<
 		if (functionSignatureByStatement.equals("no-function-found"))
 			return;
 
-		if (contract.getFunctionSignatureByString(functionSignatureByStatement).isProtected()) {
+		Signature signature = contract.getFunctionSignatureByString(functionSignatureByStatement);
+		if (signature == null)
+			return;
+
+		if (signature.isProtected()) {
 			log.warn(
 					"[POSSIBLE] Access Control Incompleteness vulnerability at pc {} (line {}) coming from pc {} (line {}).",
 					((ProgramCounterLocation) sink.getLocation()).getPc(),

src/main/java/it/unipr/crosschain/functions/ProtectedFunctionFinder.java

@@ -86,6 +86,8 @@ private void checkForProtection(Statement sink, EVMCFG cfg, Set<Integer> jumpiPp
 
 			for (Statement functionEntryPoint : functionSignature.getEntryPoints()) {
 				Statement source = cfg.getClosestStatementOfType(functionEntryPoint, Caller.class);
+				if (source == null)
+					continue;
 
 				log.debug("Source {} at pc {} line {}",
 						source,
@@ -101,7 +103,6 @@ private void checkForProtection(Statement sink, EVMCFG cfg, Set<Integer> jumpiPp
 
 					functionSignature.setProtected(true);
 					log.info("Function {} is protected", functionSignature.getFullSignature());
-
 				}
 			}
 		}