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// Copyright 2021 Code Intelligence GmbH
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.code_intelligence.jazzer.autofuzz;
import com.code_intelligence.jazzer.api.FuzzedDataProvider;
import com.code_intelligence.jazzer.utils.Utils;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.net.URLDecoder;
import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;
public class FuzzTarget {
private static final long MAX_EXECUTIONS_WITHOUT_INVOCATION = 100;
private static String methodReference;
private static Method[] targetMethods;
private static Map<Method, Class<?>[]> throwsDeclarations;
private static long executionsSinceLastInvocation = 0;
public static void fuzzerInitialize(String[] args) {
if (args.length != 1 || !args[0].contains("::")) {
System.err.println(
"Expected the argument to --autofuzz to be a method reference (e.g. System.out::println)");
System.exit(1);
}
methodReference = args[0];
String[] parts = methodReference.split("::", 2);
String className = parts[0];
String methodNameAndOptionalDescriptor = parts[1];
String methodName;
String descriptor;
int descriptorStart = methodNameAndOptionalDescriptor.indexOf('(');
if (descriptorStart != -1) {
methodName = methodNameAndOptionalDescriptor.substring(0, descriptorStart);
// URL decode the descriptor to allow copy-pasting from javadoc links such as:
// https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html#valueOf(char%5B%5D)
try {
descriptor =
URLDecoder.decode(methodNameAndOptionalDescriptor.substring(descriptorStart), "UTF-8");
} catch (UnsupportedEncodingException e) {
// UTF-8 is always supported.
e.printStackTrace();
System.exit(1);
return;
}
} else {
methodName = methodNameAndOptionalDescriptor;
descriptor = null;
}
Class<?> targetClass;
try {
targetClass = Thread.currentThread().getContextClassLoader().loadClass(className);
} catch (ClassNotFoundException e) {
System.err.printf(
"Failed to find class %s for autofuzz, please ensure it is contained in the classpath "
+ "specified with --cp and specify the full package name%n",
className);
e.printStackTrace();
System.exit(1);
return;
}
targetMethods = Arrays.stream(targetClass.getMethods())
.filter(method
-> method.getName().equals(methodName)
&& (descriptor == null
|| Utils.getReadableDescriptor(method).equals(descriptor)))
.toArray(Method[] ::new);
if (targetMethods.length == 0) {
if (descriptor == null) {
System.err.printf("Failed to find accessible methods named %s in class %s for autofuzz.%n"
+ "Accessible methods:%n%s",
methodName, className,
Arrays.stream(targetClass.getMethods())
.map(method
-> String.format(
"%s::%s", method.getDeclaringClass().getName(), method.getName()))
.distinct()
.collect(Collectors.joining(System.lineSeparator())));
} else {
System.err.printf("Failed to find accessible methods named %s in class %s for autofuzz.%n"
+ "Accessible methods with that name:%n%s",
methodName, className,
Arrays.stream(targetClass.getMethods())
.filter(method -> method.getName().equals(methodName))
.map(method
-> String.format("%s::%s%s", method.getDeclaringClass().getName(),
method.getName(), Utils.getReadableDescriptor(method)))
.distinct()
.collect(Collectors.joining(System.lineSeparator())));
}
System.exit(1);
}
throwsDeclarations =
Arrays.stream(targetMethods)
.collect(Collectors.toMap(method -> method, Method::getExceptionTypes));
}
public static void fuzzerTestOneInput(FuzzedDataProvider data) throws Throwable {
Method targetMethod;
if (targetMethods.length == 1) {
targetMethod = targetMethods[0];
} else {
targetMethod = data.pickValue(targetMethods);
}
try {
Meta.autofuzz(data, targetMethod);
executionsSinceLastInvocation = 0;
} catch (AutofuzzConstructionException e) {
if (Meta.isDebug()) {
e.printStackTrace();
}
// Ignore exceptions thrown while constructing the parameters for the target method. We can
// only guess how to generate valid parameters and any exceptions thrown while doing so
// are most likely on us. However, if this happens too often, Autofuzz got stuck and we should
// let the user know.
executionsSinceLastInvocation++;
if (executionsSinceLastInvocation >= MAX_EXECUTIONS_WITHOUT_INVOCATION) {
System.err.printf("Failed to generate valid arguments to '%s' in %d attempts; giving up%n",
methodReference, executionsSinceLastInvocation);
System.exit(1);
}
} catch (AutofuzzInvocationException e) {
executionsSinceLastInvocation = 0;
Throwable cause = e.getCause();
Class<?> causeClass = cause.getClass();
// Do not report exceptions declared to be thrown by the method under test.
for (Class<?> declaredThrow : throwsDeclarations.get(targetMethod)) {
if (declaredThrow.isAssignableFrom(causeClass)) {
return;
}
}
throw cause;
} catch (Throwable t) {
System.err.println("Unexpected exception encountered during autofuzz");
t.printStackTrace();
System.exit(1);
}
}
}
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