mirror of https://github.com/google/oss-fuzz.git
53 lines
2.5 KiB
Java
53 lines
2.5 KiB
Java
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// 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 org.apache.logging.log4j.Level;
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import org.apache.logging.log4j.LogManager;
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import org.apache.logging.log4j.Logger;
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import org.apache.logging.log4j.core.appender.FileAppender;
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import org.apache.logging.log4j.core.config.Configurator;
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import org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
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import org.apache.logging.log4j.core.config.builder.api.RootLoggerComponentBuilder;
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import org.apache.logging.log4j.core.config.builder.impl.DefaultConfigurationBuilder;
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import org.apache.logging.log4j.status.StatusLogger;
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// This fuzzer reproduces the log4j RCE vulnerability CVE-2021-44228.
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public class Log4jFuzzer {
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private final static Logger log = LogManager.getLogger(Log4jFuzzer.class.getName());
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public static void fuzzerTestOneInput(FuzzedDataProvider data) {
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log.error(data.consumeRemainingAsString());
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}
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public static void fuzzerInitialize() {
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// Install a logger that constructs the log message, but never prints it.
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// This noticeably increases the fuzzing performance
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DefaultConfigurationBuilder configBuilder = new DefaultConfigurationBuilder();
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AppenderComponentBuilder fuzzingAppender = configBuilder.newAppender("nullAppender", FileAppender.PLUGIN_NAME);
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fuzzingAppender.addAttribute("fileName", "/dev/null");
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configBuilder.add(fuzzingAppender);
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RootLoggerComponentBuilder rootLogger = configBuilder.newRootLogger();
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rootLogger.add(configBuilder.newAppenderRef("nullAppender"));
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configBuilder.add(rootLogger);
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Configurator.reconfigure(configBuilder.build());
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// Disable logging of exceptions caught in log4j itself.
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StatusLogger.getLogger().reset();
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StatusLogger.getLogger().setLevel(Level.OFF);
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}
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}
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