这里以 java 作为示例语言进行分析
在配置好CodeQL以后，用户目录下的 codeql-home/codeql 文件夹保存了CodeQL的 CLI 部分，它的目录结构如下，这里省略了部分无关文件
├── codeql
├── java
│ ├── codeql-extractor.yml
│ ├── semmlecode.dbscheme
│ ├── semmlecode.dbscheme.stats
│ └── tools
│ ├── autobuild-fat.jar
│ ├── autobuild.cmd
│ ├── autobuild.sh
│ ├── codeql-java-agent.jar
│ ├── compiler-tracing.spec
│ ├── macos
│ ├── pre-finalize.sh
│ ├── semmle-extractor-java.jar
│ └── tracing-config.lua
└──── tools
├── codeql.jar
├── osx64
├── test
└── tracer
CodeQL的入口文件为 codeql ，这是一个 shell 脚本，主要目的就是为调用 codeql.jar 做准备，包括检查环境和配置环境变量。 codeql.jar 是CodeQL的核心文件，包含了命令行解析、数据库创建和查询引擎相关的代码。
这里以创建数据库的指令为例。创建数据库要经过下面三步
`initialize 初始化数据库，用到codeql.jar build 生成trap文件，用到codeql-java-agent.jar，semmle-extractor-java.jar finalize 将trap文件导入数据库，用到pre-finalize.sh，codeql.jar`
我们按照这个流程，分成三步进行分析
我们新建一个IDEA工程，将 codeql.jar 导入为依赖库，然后编写如下代码
`package cokeBeer;
import com.semmle.cli2.CodeQL;
import java.io.File;
public class RunCreate {
public static void main(String[] args) {
//参数部分可以自由配置，只要能正常运行database create的参数即可
String UserHome=System.getProperty("user.home");
String language="java";
String command="mvn clean package";
String ProjectName="java-sec-code";
String CodeQLHome=String.join(File.separator,UserHome,"codeql-home");
String SourceRoot=String.join(File.separator,CodeQLHome,"source","java-source");
String DatabaseRoot=String.join(File.separator,CodeQLHome,"database","java-database");
String source=String.join(File.separator,SourceRoot,ProjectName);
String database=String.join(File.separator,DatabaseRoot,ProjectName);
String[] QLArgs=new String[]{"database","create","-v","--overwrite","-l",language,"-s",source,"-c",command,database};
//调用CodeQL的入口方法，可以在这里下断点
CodeQL.main(QLArgs);
}
}`
这里选择 这个项目作为测试项目。具体选择的项目内容对分析过程没有影响，编译指令正确即可。
在入口方法处打上断点，开始调试，接下来的方法调用过程如下
`com.semmle.cli2.CodeQL#main com.semmle.cli2.picocli.SubcommandMaker#runMain(java.lang.String[]) com.semmle.cli2.picocli.SubcommandMaker#runMain(java.lang.String[], java.util.function.Function<com.semmle.cli2.picocli.SubcommandCommon,java.lang.Integer>, boolean) java.util.function.Function#apply com.semmle.cli2.picocli.SubcommandCommon#call com.semmle.cli2.database.CreateCommand#executeSubcommand`
最后是进入到了 CreataeCommmand 类，这个类处理创建数据库相关的操作，这里简化了部分代码，方法逻辑流程如下
`protected void executeSubcommand() throws SubcommandDone {
// 初始化数据库
this.runPlumbingInProcess(InitCommand.class, new Object[]{this.initOptions, "--source-root=" + this.sourceRoot, "--allow-missing-source-root=" + this.traceCommandOptions.hasWorkingDir(), "--allow-already-existing", "--", this.initOptions.directory});
// 运行编译指令
this.runPlumbingInProcess(TraceCommandCommand.class, new Object[]{threadsOption(this.threads), ramOption(this.ram), this.tracingOptions, this.traceCommandOptions, this.extractorOptionsOptions, indexTracelessOption, multispec, "--", multispec.directory, commandLine});
// finalize
this.runPlumbingInProcess(FinalizeCommand.class, new Object[]{threadsOption(this.threads), ramOption(this.ram), this.finalizeParams, multispec, "--", multispec.directory});
}
}`
我们进入初始化数据库的代码，调用链如下
`com.semmle.cli2.picocli.SubcommandCommon#runPlumbingInProcess com.semmle.cli2.picocli.PlumbingRunner#run com.semmle.cli2.database.InitCommand#executeSubcommand com.semmle.cli2.database.InitCommand#initOneDatabase`
最后是进入了 InitCommand 类，这个类负责初始化数据库。 initOneDatabase 的代码简化后如下
private void initOneDatabase(String language, Path databaseDir, long linesOfCode, Optional<String> shaAnalyzed) {
// 搜索extractor
Map<String, List<Path>> allExtractors = ((ResolveLanguagesResult)this.callPlumbingInProcess(ResolveLanguagesCommand.class, new Object[]{this.options.extractorOptions})).getExtractorRoots();
List<Path> found = (List)allExtractors.get(language);
Path packRoot = (Path)found.get(0);
// 创建extractor对象
CodeQLExtractor extractor = new CodeQLExtractor(packRoot);
DbInfo dbInfo = new DbInfo(this.sourceRoot.toString(), extractor.usesUnicodeNewlines(), extractor.getColumnKind(), language, allExtractors, linesOfCode, (String)shaAnalyzed.orElse((Object)null), CodeQLVersion.currentVersion().version);
// 创建 skeleton
DatabaseLayout layout = DatabaseLayout.create(databaseDir, dbInfo);
}`
运行完成后，数据库目录下会出现 codeql-database.yml 文件
`java-sec-code $ tree -L 1 . ├── codeql-database.yml └── log`
从 initalize 部分返回以后，就进入了 build 部分，这里我们先调试几步，调用链如下
com.semmle.cli2.picocli.SubcommandCommon#runPlumbingInProcess com.semmle.cli2.picocli.PlumbingRunner#run com.semmle.cli2.database.TraceCommandCommand#executeSubcommand com.semmle.cli2.database.DatabaseProcessCommandCommon#executeSubcommand`
一是读取 compile.spec 文件，创建 Tracer ，对应代码如下
TracerSetup tracerSetup = this.getTracerSetup(this.logger(), databases, scratchFolder, logFolder, extractors);`
getTracerSetup 里面又调用了 getTracingSpec
`extractor.getTracingSpec().get()`
内容如下，这里 getTracingSpec 会去找 extractor 根目录下的 tools/compile.spec 文件并读取
`public Optional<Path> getTracingSpec() {
Path tools = this.extractorRoot.resolve("tools");
Path platformTools = tools.resolve(CodeQLDist.currentPlatform().name());
Iterator var3 = Arrays.asList(platformTools.resolve("compiler-tracing.spec"), tools.resolve("compiler-tracing.spec")).iterator();
Path candidate;
do {
if (!var3.hasNext()) {
return Optional.empty();
}
candidate = (Path)var3.next();
} while(!Files.isRegularFile(candidate, new LinkOption[0]) || !Files.isReadable(candidate));
return Optional.of(candidate);
}`
用于示例的是 java 的 extractor ，我们很容易找到对应的 compile.spec ，内容如下
`jvm_prepend_arg -javaagent:${config_dir}/codeql-java-agent.jar=ignore-project,java
jvm_prepend_arg -Xbootclasspath/a:${config_dir}/codeql-java-agent.jar`
可见CodeQL会在build前准备好调用 code-java-agent.jar 相关的参数
二是创建进程，运行build指令。
`Builder8 p = new Builder8(cmdArgs, LogbackUtils.streamFor(this.logger(), "build-stdout", true), LogbackUtils.streamFor(this.logger(), "build-stderr", true), Env.systemEnv().getenv(), workingDir.toFile());
this.env.addToProcess(p);
List<String> cmdProcessor = new ArrayList();
CommandLine.addCommandProcessor(cmdProcessor, this.env.expander);
p.prependArgs(cmdProcessor);
tracerSetup.enableTracing(p);
StreamAppender streamOutAppender = new StreamAppender(Streams.out());
int result;
try {
LogbackUtils.addAppender(streamOutAppender);
result = p.execute();
} finally {
LogbackUtils.removeAppender(streamOutAppender);
}`
经过一番设置，进程运行时的命令行如下
`codeql-home/codeql/tools/osx64/preload_tracer mvn clean package`
关键环境变量如下
`CODEQL_EXTRACTOR_JAVA_ROOT -> codeql-home/codeql/java CODEQL_SCRATCH_DIR -> codeql-home/database/java-database/java-sec-code/working CODEQL_EXTRACTOR_JAVA_LOG_DIR -> codeql-home/database/java-database/java-sec-code/log CODEQL_EXTRACTOR_JAVA_SOURCE_ARCHIVE_DIR -> codeql-home/database/java-database/java-sec-code/src CODEQL_EXTRACTOR_JAVA_TRAP_DIR -> codeql-home/database/java-database/java-sec-code/trap/java SEMMLE_JAVA_TOOL_OPTIONS -> -javaagent:codeql-home/codeql/java/tools/codeql-java-agent.jar=ignore-project,java -Xbootclasspath/a:codeql-home/codeql/java/tools/codeql-java-agent.jar`
因为这里调用的 preload_tracer 为二进制文件，所以直接分析它的具体行为较为困难。
但是我们可以推测出， preload_tracer 会监控编译的过程。当需要运行 JVM 时， preload_tracer 会添加准备好的 -javaagent 参数，使得 codeql-java-agent.jar 参与到编译过程中去。
所以我们接下来的任务是分析 codeql-java-agent.jar 的行为
1.3 codeql-java-agent.jar
这一部分需要读者对于 java-agent 技术和 ASM 技术有一定了解
java 源文件文件一般使用 javac 作为编译程序，生成类文件。但是 javac 仅仅是一个封装程序，其实际的编译操作是调用 com.sun.tools.javac 包下的类来完成的。如果使用 java-agent 技术，劫持 com.sun.tools.javac 包下的关键方法，就能自定义编译行为。
我们编写如下代码来调试 codeql-java-agent.jar
`package cokeBeer;
import com.sun.tools.javac.main.Main;
import com.sun.tools.javac.util.Context;
public class RunAgent {
public static void main(String[] args) throws Exception{
Main main=new Main("");
String[] arg=new String[]{"Test.java"};
main.compile(arg,new Context());
System.out.println("run agent");
}
}
为了调试 codeql-java-agent.jar ，首先将其作为库文件导入IDEA，然后在运行配置中添加 vmoptions 如下
`-javaagent:your-codeql-home/codeql/java/tools/codeql-java-agent.jar=ignore-project,java`
同时在运行配置中添加环境变量如下
`CODEQL_EXTRACTOR_JAVA_ROOT=your-codeql-home/codeql/java CODEQL_EXTRACTOR_JAVA_LOG_DIR=your-test-dir/log`
再找到入口方法 com.semmle.extractor.java.InterceptingAgent#premain 打上断点，就可以开始调试了
`public static void premain(String agentArgs, Instrumentation inst) {
inst.addTransformer(new InterceptingAgent(agentArgs, new Interceptor[0]));
}`
这里我们看到 premain 创建了一个 InterceptingAgent 类型的对象，然后添加为 Transformer
我们先看 InterceptingAgent 的构造方法
`public InterceptingAgent(String agentArgs, Interceptor... extraInterceptors) {
// 略去部分无关代码
Set<String> args = new LinkedHashSet(Arrays.asList(agentArgs.split(",")));
Iterator var6 = args.iterator();
while(var6.hasNext()) {
String arg = (String)var6.next();
if (!arg.equals("ignore-project")) {
if (arg.equals("java")) {
this.interceptors.add(new JavacMainInterceptor());
this.interceptors.add(new JavacToolInterceptor());
this.interceptors.add(new ECJInterceptor());
this.interceptors.add(new TakariLifecycleJdtInterceptor());
if (Boolean.parseBoolean(System.getenv("CODEQL_EXTRACTOR_JAVA_JSP"))) {
this.interceptors.add(new JasperJdtInterceptor());
this.interceptors.add(new JasperJspcInterceptor());
}
} else if (arg.equals("kotlin")) {
this.interceptors.add(new KotlinInterceptor());
} else {
warn(1, "Unrecognized agent specification: " + arg);
}
}
}
}`
可以看出，根据输入参数的不同，会创建不同类型的 Interceptor ，插入到 this.interceptors 去。这里我们的输入参数为 ignore-project,java ，所以会插入 JavacMainInterceptor 和 JavacToolInteceptor
然后我们看 InterceptingAgent 的 tranform 方法，这个方法会在类加载时被系统主动回调
`public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) {
if (loader == null && !bootstrapLoadableClasses.contains(className)) {
info(2, "Skipping bootstrap-loaded class " + className);
return null;
} else if ((!className.startsWith("java/") || className.equals("java/lang/Shutdown")) && !className.startsWith("javax/") && !className.startsWith("sun/")) {
if (className.startsWith("com/semmle/extractor/java/interceptors/")) {
info(2, "Skipping intercept handler class " + className);
return null;
} else if (className.startsWith("jdk/internal/reflect/")) {
info(2, "Skipping reflection class " + className);
return null;
} else if (className.startsWith("com/semmle/org/objectweb/asm/")) {
info(2, "Skipping ASM class " + className);
return null;
} else {
boolean intercept = false;
Iterator var7 = this.interceptors.iterator();
while(var7.hasNext()) {
Interceptor i = (Interceptor)var7.next();
if (i.interceptType(className)) {
intercept = true;
break;
}
}
//对于需要拦截的类，接下来使用ASM技术进行分析
...
}
} else {
info(2, "Skipping system class " + className);
return null;
}
}`
可以看到 if-else 判断过滤了 java 的内置类，以及 CodeQL 本身包含的类
然后遍历 this.interceptors ，调用 interceptType 方法进行判断。 interceptType 方法要求输入的类名必须和 interceptor 内置的拦截类名一致
例如 JavacMainInterceptor ，它的内置的拦截类就是 com.sun.tools.javac.main.Main
`public boolean interceptType(String binaryTypeName) {
return binaryTypeName.equals("com/sun/tools/javac/main/Main");
}`
当成功匹配以后，就使用 ASM 技术，对这个类进行改造。调用 ASM 的代码如下
`if (!intercept) {
info(2, "Skipping class with no interested interceptor: " + className);
return null;
} else {
info(1, "Transforming " + className);
try {
ClassReader reader = new ClassReader(classfileBuffer);
if ((reader.getAccess() & 512) != 0) {
info(2, "Skipping interface " + className);
return null;
} else {
ClassWriter writer = new ClassWriter(reader, 1);
reader.accept(new RewriteMethods(writer, className, this.collectMemberSignatures(classfileBuffer)), 0);
return writer.toByteArray();
}
} catch (RuntimeException var9) {
log("ERROR: Exception while processing " + className + ": " + var9);
var9.printStackTrace(System.out);
log("Current class loader: " + loader);
throw var9;
}
}`
这里是创建了一个 RewriteMethods 类型的对象，继承 ASM 中的 ClassVistor ，来重写类文件。这个 RewriteMethods 主要做两件事情，一是拦截并改造特定类方法，这里需要看 visitMethod 方法，它创建了一个 InterceptMethod 类型的对象
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
return new InterceptMethod(super.visitMethod(access, name, desc, signature, exceptions), access, name, desc);
}`
InterceptMethod 又继承了 ASM 中的 MethodVistor ，它实现了 applyInterceptors 方法，内部会尝试遍历 this.interceptors 保存的 Interceptor ，然后调用他们的 intercept 方法。
`private void applyInterceptors(boolean before) {
InterceptingAgent.info(3, "Considering method " + this.name + this.desc + " in " + RewriteMethods.this.binaryTypeName + ".");
Iterator var2 = InterceptingAgent.this.interceptors.iterator();
while(var2.hasNext()) {
Interceptor i = (Interceptor)var2.next();
try {
// 这里调用了下面的applyInterceptor
this.applyInterceptor(i, before);
} catch (Throwable var5) {
InterceptingAgent.log("ERROR: Interceptor of type " + i.getClass() + " caused an exception: " + var5);
var5.printStackTrace(System.out);
}
}
}
private void applyInterceptor(Interceptor i, boolean before) {
if (i.interceptType(RewriteMethods.this.binaryTypeName)) {
Interceptor.Interception interception = i.intercept(RewriteMethods.this.binaryTypeName, RewriteMethods.this.classMembers, this.name, this.desc, before);
if (interception != null) {
InterceptingAgent.info(1, "Interceptor " + i + " wants to call " + interception + " for " + RewriteMethods.this.binaryTypeName + "." + this.name + this.desc + ".");
this.instrument(interception);
} else {
InterceptingAgent.info(2, "Interceptor " + i + " is not interested in " + RewriteMethods.this.binaryTypeName + "." + this.name + this.desc + ".");
}
}
}`
这里调试时会调用到 JavacMainInterceptor 的 intercept 方法，里面拦截 com.sun.tools.java.main.Main 类型的两个 compile 方法，这两个方法都是负责编译源文件的方法
`public Interceptor.Interception intercept(String binaryTypeName, Set<String> classMembers, String methodName, String methodDescriptor, boolean before) {
if (before) {
return null;
} else {
if (methodName.equals("compile")) {
if (methodDescriptor.equals("([Ljava/lang/String;Lcom/sun/tools/javac/util/Context;)Lcom/sun/tools/javac/main/Main$Result;")) {
return new Interceptor.Interception("com/semmle/extractor/java/interceptors/JavacMainInterceptor", "void javacMainResult(Object,String[])", new Interceptor.CallWith[]{CallWith.STACK_TOP, CallWith.FIRST_ARG});
}
if (methodDescriptor.equals("([Ljava/lang/String;Lcom/sun/tools/javac/util/Context;)I")) {
return new Interceptor.Interception("com/semmle/extractor/java/interceptors/JavacMainInterceptor", "int javacMainInt(int,String[])", new Interceptor.CallWith[]{CallWith.FIRST_ARG});
}
}
return null;
}
}`
然后创建对应的 Interception 类型的对象并返回，从 applyInterceptor 方法中看到返回值会被传递给 instrument 方法，这个方法的向类字节码中写入了一个方法调用 SEMMLE_INTERCEPT$0
`private void instrument(Interceptor.Interception interception) {
Integer idx = (Integer)RewriteMethods.this.applicableInterceptions.get(interception);
if (idx == null) {
idx = RewriteMethods.this.applicableInterceptions.size();
RewriteMethods.this.applicableInterceptions.put(interception, idx);
}
Interceptor.CallWith[] var3 = interception.callWith();
int var4 = var3.length;
for(int var5 = 0; var5 < var4; ++var5) {
Interceptor.CallWith cw = var3[var5];
switch (cw) {
case ALL_ARGS:
this.loadArgs();
break;
case ALL_ARGS_AS_ARRAY:
this.loadArgArray();
break;
case FIRST_ARG:
this.loadArg(0);
break;
case CLASS:
this.visitLdcInsn(RewriteMethods.this.binaryTypeName);
break;
case METHOD_NAME_AND_DESC:
this.visitLdcInsn(this.name);
this.visitLdcInsn(this.desc);
break;
case STACK_TOP:
this.visitInsn(89);
break;
case THIS:
if (!this.isStatic && !this.name.equals("<init>")) {
this.visitVarInsn(25, 0);
} else {
this.visitInsn(1);
}
}
}
Method method = Method.getMethod(interception.methodDecl());
this.visitMethodInsn(184, RewriteMethods.this.binaryTypeName, "SEMMLE_INTERCEPT$" + idx, method.getDescriptor(), false);
}`
RewriteMethods 做的第二件事情是创建一个新方法，这个方法就是上面调用的方法 SEMMLE_INTERCEPT$0
这个一部分对应着它的 visitEnd 方法，里面使用 ASM 技术，构造了这个新方法。
为了直观展示，我们直接获取最终转换好的字节码进行反编译。最终发生变化的部分如下
`public Result compile(String[] var1, Context var2) {
Result var10000 = this.compile(var1, var2, List.nil(), (Iterable)null);
SEMMLE_INTERCEPT$0(var10000, var1);
return var10000;
}
private static void SEMMLE_INTERCEPT$0(Object var0, String[] var1) {
Object var10000 = var0;
String[] var10001 = var1;
try {
JavacMainInterceptor.javacMainResult(var10000, var10001);
} catch (NoClassDefFoundError var2) {
System.err.println("ERROR: Exception during invocation of Semmle Java compiler. Perhaps you need to put odasa-agent.jar on the boot classpath?");
var2.printStackTrace(System.err);
}
}`
可以看到，新的 compile 方法获取原 compile 方法的输入参数和编译返回值，然后交给 javacMainResult 处理
`@InterceptionMethod
public static void javacMainResult(Object result, String[] args) {
info(1, "Intercepted javac Main.compile(String[],Context): " + Arrays.toString(args));
String resultName = result.toString();
int javacExitCode = getJavacExitCode(resultName);
int odasaJavacExitCode = Utils.invokeOdasaJavac(javacExitCode, args);
if (javacExitCode == 0 && odasaJavacExitCode != 0) {
throw new Error("Fatal extractor error detected. Attempting to abort build commands.");
}
}`
里面调用 Utils.invoke0dasaJavac ，之后的调用链如下
`com.semmle.extractor.java.Utils#invokeOdasaJavac(int, java.lang.String[]) com.semmle.extractor.java.Utils#invokeOdasaJavac(int, java.lang.String[], boolean) com.semmle.extractor.java.Utils#invokeOdasaJavac(int, java.lang.String[], boolean, java.util.Map<java.lang.String,java.lang.String>)`
最后一个 invoke0dasaJavac 方法内部首先配置一系列的环境变量、设置命令行参数，参数内容如下
`codeql-home/codeql/java/tools/macos/jdk-extractor-java/bin/java -Dfile.encoding=UTF-8 -Xmx1024M -Xms256M --add-opens java.base/sun.reflect.annotation=ALL-UNNAMED -classpath codeql-home/codeql/java/tools/semmle-extractor-java.jar com.semmle.extractor.java.JavaExtractor --jdk-version -1 --javac-args @@@/your-test-dir/log/ext/javac.args`
然后使用这些参数创建一个程序对象并执行
Builder b = new Builder(cmdLine, System.out, System.err);
b.removeEnvVar("JAVA_TOOL_OPTIONS");
Iterator var38 = addEnv.entrySet().iterator();
while(var38.hasNext()) {
Map.Entry<String, String> entry = (Map.Entry)var38.next();
b.putEnvVar((String)entry.getKey(), (String)entry.getValue());
}
exitCode = b.execute();`
所以这里就是使用CodeQL内置的 java 命令行程序调用 semmle-extractor-java.jar
有了这些参数，我们可以主动调用 semmle-extractor-java.jar 了
运行 semmle-extractor-java.jar 会解析项目源代码，生成 trap 文件
这里我们将 semmle-extractor-java.jar 作为依赖库添加到IDEA
并编写如下代码来调试 semmle-extractor-java.jar ，其中调用参数来自上面的分析过程
`package cokeBeer;
import com.semmle.extractor.java.JavaExtractor;
import java.io.File;
public class RunExtractor {
public static void main(String[] args) {
String argPath="@@@/your-test-dir/log/ext/javac.args");
String[] ExtractorArgs=new String[]{"--jdk-version","-1","--javac-args",argPath};
JavaExtractor.main(ExtractorArgs);
}
}`
为了调试 semmle-extractor-java.jar ，首先将其作为库文件导入IDEA，然后在运行配置中添加环境变量如下
`TRAP_FOLDER=your-test-dir/trap/java SOURCE_ARCHIVE=your-test-dir/src`
在入口方法处打上断点，开始调试。 JavaExtractor#main 首先创建一个 JavaExtractor 类型的对象
`public static void main(String[] args) {
String allArgs = StringUtil.glue(" ", args);
JavaExtractor extractor = new JavaExtractor(args);
boolean hasJavacErrors = false;
try {
hasJavacErrors = !extractor.runExtractor();
} catch (Throwable var8) {
...
} finally {
extractor.close();
}
}`
然后运行 com.semmle.extractor.java.JavaExtractor#runExtractor 方法，里面使用 JavacCompiler 对源文件进行解析，然后利用解析信息生成 trap 文件
`boolean runExtractor() {
// 省略了部分日志相关代码
// 准备编译环境
Context context = this.output.getContext();
JavacFileManager.preRegister(context, this.specialSourcepathHandling);
Arguments arguments = this.setupJavacOptions(context);
Options.instance(context).put("ignore.symbol.file", "ignore.symbol.file");
JavaFileManager jfm = (JavaFileManager)context.get(JavaFileManager.class);
JavaFileManager bfm = jfm instanceof DelegatingJavaFileManager ? ((DelegatingJavaFileManager)jfm).getBaseFileManager() : jfm;
JavacFileManager dfm = (JavacFileManager)bfm;
dfm.handleOptions(arguments.getDeferredFileManagerOptions());
arguments.validate();
if (jfm.isSupportedOption(Option.MULTIRELEASE.primaryName) == 1) {
Target target = Target.instance(context);
List<String> list = List.of(target.multiReleaseValue());
jfm.handleOption(Option.MULTIRELEASE.primaryName, list.iterator());
}
JavaCompiler compiler = JavaCompiler.instance(context);
compiler.genEndPos = true;
Set<JavaFileObject> fileObjects = arguments.getFileObjects();
// 解析源文件
javac_extend.com.sun.tools.javac.util.List<JCTree.JCCompilationUnit> parsedFiles = compiler.parseFiles(fileObjects);
compiler.enterTrees(compiler.initModules(parsedFiles));
Queue<Queue<javac_extend.com.sun.tools.javac.comp.Env<AttrContext>>> groupedTodos = Todo.instance(context).groupByFile();
int prevErr = 0;
while(true) {
while(true) {
JCTree.JCCompilationUnit cu;
while(true) {
Queue todo;
do {
cu = null;
Iterator var23 = todo.iterator();
while(var23.hasNext()) {
javac_extend.com.sun.tools.javac.comp.Env<AttrContext> env = (javac_extend.com.sun.tools.javac.comp.Env)var23.next();
if (cu == null) {
cu = env.toplevel;
} else if (cu != env.toplevel) {
throw new CatastrophicError("Not grouped by file: CUs " + cu + " and " + env.toplevel);
}
}
} while(cu == null);
try {
Queue<javac_extend.com.sun.tools.javac.comp.Env<AttrContext>> queue = compiler.attribute(todo);
String envFlowChecks = System.getenv("CODEQL_EXTRACTOR_JAVA_FLOW_CHECKS");
if (envFlowChecks == null || Boolean.valueOf(envFlowChecks)) {
compiler.flow(queue);
}
break;
} catch (StackOverflowError | Exception var36) {
this.logThrowable(cu, var36);
}
}
try {
CharSequence cachedContent = dfm.getCachedContent(cu.getSourceFile());
if (cachedContent == null) {
try {
cachedContent = cu.getSourceFile().getCharContent(false);
} catch (IOException var37) {
this.logThrowable(cu, var37);
continue;
}
}
String contents = ((CharSequence)cachedContent).toString();
// 抽取解析信息，创建trap文件
(new CompilationUnitExtractor(this.output, cu, this.dw)).process(contents);
} catch (StackOverflowError | Exception var38) {
this.logThrowable(cu, var38);
}
break;
}
}
}`
我们进入最后生成 trap 文件的方法 com.semmle.extractor.java.CompilationUnitExtractor#process
里面创建了 JavaTrapWriter 类型的对象，然后依次调用各种 Extractor ，抽取信息写入 trap 文件
`public void process(String contents) {
JavaFileObject sourceFile = this.compilationUnit.getSourceFile();
if (sourceFile.getKind() == Kind.SOURCE) {
File file = PathTransformer.std().canonicalFile(sourceFile.getName());
String outputPath = ClassFileLocations.getClassFileLocation(sourceFile.getName()).getOutputPath();
File outputFile = PathTransformer.std().canonicalFile(outputPath);
this.output.setCurrentSourceFile(outputFile);
OdasaOutput.TrapLocker trapLocker = this.output.getTrapLockerForCurrentSourceFile();
try {
// 创建writer
OdasaOutput.JavaTrapWriter writer = trapLocker.getTrapWriter();
try {
if (writer != null) {
OnDemandExtractor onDemand = new OnDemandExtractor(this.output, writer, this.dw);
TreeExtender treeExtender = new TreeExtender(file, contents, this.compilationUnit, this.dw);
// 抽取编译单元信息
this.extractCompilationUnit(contents, writer, onDemand, treeExtender);
Iterator var10 = this.compilationUnit.getTypeDecls().iterator();
while(var10.hasNext()) {
JCTree aClass = (JCTree)var10.next();
if (aClass instanceof JCTree.JCClassDecl) {
// 抽取AST信息
(new ClassDeclExtractor(writer, treeExtender, onDemand, (JCTree.JCClassDecl)aClass, this.compilationUnit, this.dw)).process();
}
}
treeExtender.writeCommentData(writer);
// 抽取类、方法的基本信息以及继承和从属信息
onDemand.extract();
String rootUri = Env.systemEnv().get("CODEQL_EXTRACTOR_JAVA_JSP_ROOT_URI");
String destDir = Env.systemEnv().get("CODEQL_EXTRACTOR_JAVA_JSP_DEST_DIR");
if (rootUri != null && destDir != null) {
String packge = this.compilationUnit.packge.getQualifiedName().toString();
String smapClassName = packge + "/" + FileUtil.basename(outputFile);
(new SmapExtractor(outputFile, smapClassName, destDir, rootUri, this.output, writer, this.dw)).extract();
}
}
} catch (Throwable var16) {
if (writer != null) {
try {
writer.close();
} catch (Throwable var15) {
var16.addSuppressed(var15);
}
}
throw var16;
}
if (writer != null) {
writer.close();
}
} catch (Throwable var17) {
if (trapLocker != null) {
try {
trapLocker.close();
} catch (Throwable var14) {
var17.addSuppressed(var14);
}
}
throw var17;
}
if (trapLocker != null) {
trapLocker.close();
}
}
}`
先看 extractCompilationUnit 方法，它向 trap 文件写入包名称信息以及导入信息
`private void extractCompilationUnit(String contents, TrapWriter writer, OnDemandExtractor onDemand, TreeExtender treeExtender) {
this.output.writeCurrentSourceFileToSourceArchive(contents);
TrapWriter.Label compilationUnitId = treeExtender.writeSourceFile(writer);
TrapWriter.Label packageId = onDemand.getPackageKey(this.compilationUnit.packge);
writer.addTuple(JavaTable.CuPackage, new Object[]{compilationUnitId, packageId});
Iterator var7 = this.compilationUnit.getImports().iterator();
while(var7.hasNext()) {
JCTree.JCImport i = (JCTree.JCImport)var7.next();
classifyImport(treeExtender, writer, onDemand, i);
}
}`
然后是 com.semmle.extractor.java.ClassDeclExtractor#process 方法，它访问整个语法树，向 trap 文件写入表达式和语句信息
`public void process() {
this.log.info("Processing file " + this.compilationUnit.getSourceFile().getName());
this.visitTree(this.classToExtract);
}`
然后是 com.semmle.extractor.java.OnDemandExtractor#extract 方法，其内部会调用
`com.semmle.extractor.java.OnDemandExtractor#extractModules com.semmle.extractor.java.OnDemandExtractor#extractJarInfo`
分别抽取模块信息和 jar 包清单信息
然后调用 com.semmle.extractor.java.OnDemandExtractor#extractMembersToCurrentWriter 方法，抽取成员变量和成员方法信息
完成分析以后，之前设置的 trap 目录 your-test-dir/trap/java 下就会出现多个 trap.gz 文件，这里我们简单解压一个来分析一下部分内容
源代码
`public static void main(String[] args) {
System.out.println("hello");
}`
生成结果
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"callable;{#10007}.main({#10020}){#10009}"
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"loc,{#10000},2,24,2,27"
locations_default(#10029,#10000,2,24,2,27)
hasLocation(#10028,#10029)
numlines(#10028,3,3,0)
#10030=*
stmts(#10030,0,#10028,0,#10028)
#10031=*
locations_default(#10031,#10000,2,44,4,5)
hasLocation(#10030,#10031)
numlines(#10030,3,3,0)
#10032=*
exprs(#10032,62,#10009,#10028,-1)
callableEnclosingExpr(#10032,#10028)
#10033=*
locations_default(#10033,#10000,2,19,2,22)
hasLocation(#10032,#10033)
numlines(#10032,1,1,0)
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"params;{#10028};0"
params(#10034,#10020,0,#10028,#10034)
paramName(#10034,"args")
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"loc,{#10000},2,29,2,41"
locations_default(#10035,#10000,2,29,2,41)
hasLocation(#10034,#10035)
#10036=*
exprs(#10036,63,#10020,#10034,-1)
callableEnclosingExpr(#10036,#10028)
#10037=*
locations_default(#10037,#10000,2,29,2,36)
hasLocation(#10036,#10037)
numlines(#10036,1,1,0)
#10038=*
exprs(#10038,62,#10019,#10036,0)
callableEnclosingExpr(#10038,#10028)
#10039=*
locations_default(#10039,#10000,2,29,2,34)
hasLocation(#10038,#10039)
numlines(#10038,1,1,0)
#10040=*
stmts(#10040,14,#10030,0,#10028)
#10041=*
locations_default(#10041,#10000,3,9,3,36)
hasLocation(#10040,#10041)
numlines(#10040,1,1,0)
#10042=*
exprs(#10042,61,#10009,#10040,0)
callableEnclosingExpr(#10042,#10028)
statementEnclosingExpr(#10042,#10040)
#10043=*
locations_default(#10043,#10000,3,9,3,35)
hasLocation(#10042,#10043)
numlines(#10042,1,1,0)
#10044=*
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"class;java.io.PrintStream"
exprs(#10044,60,#10045,#10042,-1)
callableEnclosingExpr(#10044,#10028)
statementEnclosingExpr(#10044,#10040)
#10046=*
locations_default(#10046,#10000,3,9,3,18)
hasLocation(#10044,#10046)
numlines(#10044,1,1,0)
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"callable;{#10045}.println({#10019}){#10009}"
callableBinding(#10042,#10047)
#10048=*
exprs(#10048,22,#10019,#10042,0)
callableEnclosingExpr(#10048,#10028)
statementEnclosingExpr(#10048,#10040)
#10049=*
locations_default(#10049,#10000,3,28,3,34)
hasLocation(#10048,#10049)
numlines(#10048,1,1,0)
#10050=*
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"class;java.lang.System"
exprs(#10050,62,#10051,#10044,-1)
callableEnclosingExpr(#10050,#10028)
statementEnclosingExpr(#10050,#10040)
#10052=*
locations_default(#10052,#10000,3,9,3,14)
hasLocation(#10050,#10052)
numlines(#10050,1,1,0)
#[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"field;{#10051};out"
variableBinding(#10044,#10053)
namestrings("""hello""","hello",#10048)`
从最后面的 #10050=* 开始分析，这里表示刷新标签，无具体含义，但是可以被其他变量绑定为 ID
接下来的 #[[email protected]](https://tttang.com/cdn-cgi/l/email-protection)"class;java.lang.System" 表示一个全局 gloablID ，其值为 10051
再下来的 exprs(#10050,62,#10051,#10044,-1) 表示向名为 exprs 的代码表中插入一条记录，具体记录的含义可以在上面工作流程概览部分里面列举到的文件 semmlecode.dbscheme 中找到
`#keyset[parent,idx] exprs( unique int id: @expr, int kind: int ref, int typeid: @type ref, int parent: @exprparent ref, int idx: int ref );`
对应起来就是 id 为 10050 ， kind 为 62 ， typeid 为 10051 (也就是上面记录的 java.lang.System 类型)， parent 为 10044 ， idx 为 -1
经过了上面几步， trap 文件成功地被生成了。接下来就是将 trap 文件导入到代码数据库中。
现在进入最后的finalize部分，调用链如下
`com.semmle.cli2.picocli.SubcommandCommon#runPlumbingInProcess com.semmle.cli2.picocli.PlumbingRunner#run com.semmle.cli2.database.FinalizeCommand#executeSubcommand com.semmle.cli2.database.FinalizeCommand#finalizeOne`
我们看 finalizeOne 方法的实现，它首先运行 pre-finalize.sh 文件，主要目的是为数据库建立索引。然后调用 doTrapImport 方法，导入 trap 文件
`private void finalizeOne(DatabaseLayout dbLayout) throws SubcommandDone {
Path databaseDir = dbLayout.getDatabasePath();
if (dbLayout.isFinalized()) {
throw new UserError("Database " + databaseDir + " is already finalized.");
} else if (!Files.exists(dbLayout.getSourceArchiveRoot(), new LinkOption[0])) {
if (this.params.skipEmpty()) {
this.printWarning(this.emptyDatabaseMessage(databaseDir), new Object[0]);
} else {
this.printError(this.emptyDatabaseMessage(databaseDir), new Object[0]);
throw new SubcommandDone(32);
}
} else {
this.foundOneNonEmpty = true;
// 执行pre-finalize.sh
if (!this.params.suppressPreFinalize()) {
dbLayout.getExtractor().getPreFinalizeScript().ifPresent((script) -> {
Path workingDir = Paths.get(dbLayout.getSourceLocationPrefix());
this.printProgress("Running pre-finalize script {} in {}.", new Object[]{script, workingDir});
int result = this.runPlumbingInProcess(TraceCommandCommand.class, new Object[]{"--working-dir=" + workingDir, "--no-tracing", threadsOption(this.importOptions.getThreads()), ramOption(this.importOptions.getRam()), "--", databaseDir, script});
if (result != 0) {
throw new UserError("Failed to execute pre-finalize script in " + databaseDir + " [exit code: " + result + "].");
}
});
}
writeSourceLocationPrefixTrap(dbLayout);
List<Path> trapFolders = Collections.singletonList(dbLayout.getTrapFolder());
doTrapImport(this, dbLayout, this.importOptions, this.privateImportOptions, trapFolders);
dbLayout.markAsFinalized();
if (!this.params.suppressCleanup()) {
this.runPlumbingInProcess(CleanupDatabaseCommand.class, new Object[]{this.params.cleanupParams, "--", databaseDir});
}
}
}`
接着看到 doTrapImport 方法，里面先获取数据库的 schmema 文件，然后继续调用 import 指令
`static void doTrapImport(SubcommandCommon owner, DatabaseLayout dbLayout, ImportOptions importOptions, PrivateImportOptions privateImportOptions, List<Path> trapPaths) {
owner.printProgress("Running TRAP import for {}...", new Object[]{dbLayout});
SimpleTimer timer = new SimpleTimer();
Path dbscheme = importOptions.getDbscheme();
if (dbscheme == null) {
Either<Path, String> detectedDbscheme = dbLayout.getExtractor().getDbscheme();
if (!detectedDbscheme.isLeft()) {
throw new UserError((String)detectedDbscheme.getRight());
}
dbscheme = (Path)detectedDbscheme.getLeft();
}
List<Object> importCommandArgs = new ArrayList(Arrays.asList(importOptions.getRam() != null ? ResolveRamCommand.createHeapSizeOption(importOptions.getRam()) : Collections.EMPTY_LIST, "--dbscheme=" + dbscheme, threadsOption(importOptions.getThreads()), privateImportOptions, "--", dbLayout.getDatasetPath()));
importCommandArgs.addAll(trapPaths);
int result;
if (importOptions.getRam() != null) {
result = owner.spawnPlumbingAsChildProcess(ImportCommand.class, (RamOptions)null, importCommandArgs.toArray());
} else {
result = owner.runPlumbingInProcess(ImportCommand.class, importCommandArgs.toArray());
}
if (result != 0) {
throw new UserError("Dataset import for " + dbLayout.getDatasetPath() + " failed with code " + result + ".");
} else {
owner.printProgress("TRAP import complete ({}).", new Object[]{timer});
}
}`
import 指令的调用栈如下
`com.semmle.cli2.picocli.SubcommandCommon#runPlumbingInProcess com.semmle.cli2.picocli.PlumbingRunner#run com.semmle.cli2.database.FinalizeCommand#executeSubcommand com.semmle.cli2.ql.dataset.ImportCommand#executeSubcommand`
executeSubcommand 的实现如下，构建了一个 TrapImporter 类型对象，然后调用 run 方法
`protected void executeSubcommand() throws SubcommandDone {
if (Files.exists(this.datasetDir, new LinkOption[0]) && !FileUtil8.isEmptyDirectory(this.datasetDir)) {
if (!Files.isDirectory(this.datasetDir, new LinkOption[]{LinkOption.NOFOLLOW_LINKS})) {
throw new UserError("Dataset " + this.datasetDir + " exists, but is not a directory.");
}
if (!Files.isDirectory((new IMBDiskLayout(this.datasetDir, new Context("default"))).getIdPoolDir(), new LinkOption[0])) {
throw new UserError("Dataset " + this.datasetDir + " has been finalized and does not support further TRAP import.");
}
FileUtil8.strictRecursiveDelete(IMBDiskLayout.getCacheDir(this.datasetDir.resolve("default")));
}
AtomicBoolean hasErrors = new AtomicBoolean(false);
TrapImporter importer = new TrapImporter(new TRAPReaderConfig(this.privateOptions.checkUndefinedLabels(), this.privateOptions.checkUnusedLabels(), this.privateOptions.checkRepeatedLabels(), this.privateOptions.checkRedefinedLabels(), this.privateOptions.checkUseBeforeDefinition(), this.privateOptions.locationInStar(), (error) -> { hasErrors.set(true); this.printError(error, new Object[0]); }), this.datasetDir, "default", new CachingMode(), threadsOptionValue(this.threads)); try { importer.run(Arrays.asList(this.trapPaths), this.dbscheme); } catch (Throwable var6) { try { importer.close(); } catch (Throwable var5) { var6.addSuppressed(var5); } throw var6; } importer.close(); if (this.privateOptions.failOnErrors() && hasErrors.get()) { this.printError("Aborting as some errors occured during TRAP import.", new Object[0]); throw new SubcommandDone(2); } }`
run 方法内部最终实现了导入
`public void run(List<Path> trapRoots, Path targetDbscheme) {
AtomicInteger totalNumTrapFilesCounter = new AtomicInteger(0);
CancellationToken cancelToken = new CancellationToken();
CompletableFuture<List<TrapTask<LinkTarget[]>>> tasks = this.scanAndLink(trapRoots, totalNumTrapFilesCounter, this.executor);
try {
tasks.thenCompose((taskList) -> { return ImportTasksProcessor.importTrap(this.loadDbSchemeBinding(targetDbscheme), this.backend, this.executor, this.trapReaderConfig, new LogProgressTracker(totalNumTrapFilesCounter.get()), taskList, cancelToken); }).join(); } catch (CompletionException var7) { logger.error("An exception occurred during TRAP import. The database may be partial.", var7); throw Exceptions.asUnchecked(var7.getCause()); } this.copyDbSchemeFile(targetDbscheme); logger.info("Finished importing trap files."); }`
从上面的分析过程中可以看出，CodeQL其实不需要 java 项目真的可以成功编译，它只需要分析源码获取语法树即可。那么我们可以考虑跳过编译这一步，直接利用 semmle-java-extractor.jar 生成数据库，这正好可以解决某些场景下，只有反编译出的 java 源代码，但是不能成功编译的问题。
这里还是以 这个项目为例子，为了模拟无源码的环境，下面我们只使用编译好的 jar 包
下面一共用到三个关键文件夹
- /Users/cokeBeer/decompiled ：反编译出的源代码的位置 /Users/cokeBeer/test ： semmle-extractor-java 的工作文件夹 /Users/coekBeer/nonsource ：最终生成数据库的位置
首先用IDEA提供的 反编译工具对 java-sec-code-1.0.0.jar 进行反编译
`java -jar java-decompiler.jar -dgs=1 java-sec-code-1.0.0.jar <your-dst-dir>`
这里我使用的目标文件夹为 /Uesrs/cokeBeer/decompiled
然后在 /Uesrs/cokeBeer/decompiled 下找到反编译好的 java-sec-code-1.0.0.jar ，使用下面指令解压
`jar -xvf java-sec-code-1.0.0.jar`
然后在解压后的文件里面找到 BOOT-INF/classes 文件夹，这里面保存了反编译好的项目文件
`classes $ tree -L 1 . ├── application.properties ├── banner.txt ├── create_db.sql ├── logback-online.xml ├── mapper ├── org ├── static ├── templates └── url`
下面我们先进行initialize环节，新建一个文件夹 nonsource ，使用下面的指令初始化数据库
`codeql database init -l java --source-root org /Users/cokeBeer/nonsource`
这里的 source-root 参数就设置为上面解压出的源代码文件夹 org
回顾我们之前调试的过程，在完成 codeql-java-agent.jar 的处理以后， test 文件夹里面应该出现一个 log 文件夹，里面保存了调用 semmle-extractor-java.jar 需要的参数 javac.args
`log $ tree -L 2 . ├── ext │ ├── javac.args │ ├── javac.env │ ├── javac.orig │ └── javac.properties └── javac-errors.log`
然后我们可以利用这个文件作为输入，调用 semmle-extractor-java.jar
`package cokeBeer;
import com.semmle.extractor.java.JavaExtractor;
import java.io.File;
public class RunExtractor {
public static void main(String[] args) {
// 在这里用到了
String argPath="@@@/Users/cokeBeer/test/log/ext/javac.args");
String[] ExtractorArgs=new String[]{"--jdk-version","-1","--javac-args",argPath};
JavaExtractor.main(ExtractorArgs);
}
}`
同时需要配置环境变量，说明生成 trap 文件和 src 相关文件的位置，注意这里先输出到 test 文件夹
`TRAP_FOLDER=/Users/cokeBeer/test/trap/java SOURCE_ARCHIVE=/Users/cokeBeer/test/src`
我们看一下 javac.args 的内容
`-Xprefer:source -source 1.8 -target 1.8 -classpath ... -extdirs ... -endorseddirs ... -bootclasspath ... Test.java`
它的最后一行传入了编译的目标，那么我们只需要在这里替换了输入文件，就能正确调用
现在先回到 /Users/cokeBeer/decompiled/BOOT-INF/classes 文件夹，使用下面指令找到所有需要编译的 java 文件
`find org -name *.java > sources.txt`
sources.txt 可能是相对目录，可以使用 vscode 批量替换为绝对目录
`/Users/cokeBeer/decompiled/BOOT-INF/classes/org/joychou/imageConfig.java /Users/cokeBeer/decompiled/BOOT-INF/classes/org/joychou/Application.java /Users/cokeBeer/decompiled/BOOT-INF/classes/org/joychou/util/LoginUtils.java /Users/cokeBeer/decompiled/BOOT-INF/classes/org/joychou/util/HttpUtils.java /Users/cokeBeer/decompiled/BOOT-INF/classes/org/joychou/util/WebUtils.java ...`
然后将输入替换为 @/Users/cokeBeer/decompiled/BOOT-INF/classes/source.txt
`-Xprefer:source -source 1.8 -target 1.8 -classpath ... -extdirs ... -endorseddirs ... -bootclasspath ... @/Users/cokeBeer/decompiled/BOOT-INF/classes/source.txt`
然后运行之前调试 semmle-extractor-java.jar 时配置好的代码，即可在 /Users/cokeBeer/test/trap/java 文件夹下找到 trap 文件
`org $ tree -L 2
.
└── joychou
├── Application.java.set
├── Application.java.trap.gz
├── RMI
├── config
├── controller
├── dao
├── filter
├── imageConfig.java.set
├── imageConfig.java.trap.gz
├── mapper
├── security
└── util`
现在 trap 文件已经生成完毕，最后就是finalize阶段
先将 /Users/cokeBeer/test 下生成的 trap 和 src 文件夹复制到 /Users/cokeBeer/nonsource
然后运行下面的指令生成数据库
`codeql database finalize /Users/cokeBeer/nosource`
完成以后 /Users/cokeBeer/nonsource 目录结构应该如下
`nonsource $ tree -L 1 . ├── codeql-database.yml ├── db-java ├── log └── src.zip`
下面到 vscode 中导入数据库，然后编写一个命令注入的污点分析查询
`import java
import semmle.code.java.dataflow.FlowSources
import semmle.code.java.dataflow.TaintTracking
abstract class CommandInjectionSink extends DataFlow::Node {}
private class DefaultCommandInjectionSink extends CommandInjectionSink{
DefaultCommandInjectionSink(){
exists(ConstructorCall cc |cc.getAnArgument()=this.asExpr()|cc.getCallee().getDeclaringType() instanceof TypeProcessBuilder)
}
}
class CommandInjectionConfiguration extends TaintTracking::Configuration {
CommandInjectionConfiguration() { this = "CommandInjection" }
override predicate isSource(DataFlow::Node source) {
source instanceof RemoteFlowSource
}
override predicate isSink(DataFlow::Node sink) {
sink instanceof CommandInjectionSink
}
}
from DataFlow::PathNode source, DataFlow::PathNode sink, CommandInjectionConfiguration conf
where conf.hasFlowPath(source, sink)
select source, sink`
成功查询出已知漏洞
`commandInjection.ql on nonsource - finished in 0 seconds (1 results) [2022/8/11 18:52:16]`
本文从调试的角度分析了CodeQL数据库构建原理，介绍了CodeQL数据库构建过程中用到的一系列文件和参数的作用和含义。同时也演示了一种绕过编译过程的无源码构建数据库的方案
1.CodeQL构建数据库的实际过程？
使用 java 提供的 API 解析源代码，生成 trap 文件，导入数据库
2.无源代码构建的适用范围
CodeQL在构建 trap 文件时只需要解析源代码，不用真正生成类文件，这部分工作属于编译的前端。所以只需要CodeQL调用的 API 能够成功解析源代码，就能完成无源代码构建。
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/291173.html