53 lines
2.1 KiB
Java
53 lines
2.1 KiB
Java
// Copyright 2021 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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////////////////////////////////////////////////////////////////////////////////
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import com.code_intelligence.jazzer.api.FuzzedDataProvider;
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import java.util.Base64;
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public class ExampleValueProfileFuzzer {
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private static String base64(byte[] input) {
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return Base64.getEncoder().encodeToString(input);
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}
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private static long insecureEncrypt(long input) {
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long key = 0xefe4eb93215cb6b0L;
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return input ^ key;
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}
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public static void fuzzerTestOneInput(FuzzedDataProvider data) {
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// Without -use_value_profile=1, the fuzzer gets stuck here as there is no direct correspondence
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// between the input bytes and the compared string. With value profile, the fuzzer can guess the
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// expected input byte by byte, which takes linear rather than exponential time.
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if (base64(data.consumeBytes(6)).equals("SmF6emVy")) {
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long[] plaintextBlocks = data.consumeLongs(2);
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if (plaintextBlocks.length != 2)
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return;
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if (insecureEncrypt(plaintextBlocks[0]) == 0x9fc48ee64d3dc090L) {
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// Without --fake_pcs (enabled by default with -use_value_profile=1), the fuzzer would get
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// stuck here as the value profile information for long comparisons would not be able to
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// distinguish between this comparison and the one above.
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if (insecureEncrypt(plaintextBlocks[1]) == 0x888a82ff483ad9c2L) {
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mustNeverBeCalled();
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}
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}
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}
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}
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private static void mustNeverBeCalled() {
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throw new IllegalStateException("mustNeverBeCalled has been called");
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}
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}
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