Add NullAway to IAST module and fix errors

dd-java-agent/agent-iast/build.gradle

@@ -1,13 +1,29 @@
+import net.ltgt.gradle.errorprone.CheckSeverity
+
 plugins {
   id 'com.github.johnrengelman.shadow'
   id 'me.champeau.jmh'
   id 'java-test-fixtures'
   id 'com.google.protobuf' version '0.8.18'
+  id 'net.ltgt.errorprone' version '3.1.0'
 }
 
 apply from: "$rootDir/gradle/java.gradle"
 apply from: "$rootDir/gradle/version.gradle"
 
+java {
+  toolchain {
+    languageVersion.set(JavaLanguageVersion.of(11))
+  }
+  sourceCompatibility = 1.8
+  targetCompatibility = 1.8
+}
+
+tasks.withType(AbstractCompile).configureEach {
+  // ensure no APIs beyond JDK8 are used
+  options.compilerArgs.addAll(['--release', '8'])
+}
+
 // First version with Mac M1 support
 def grpcVersion = '1.42.2'
 protobuf {
@@ -49,6 +65,10 @@ dependencies {
   jmh project(':dd-java-agent:agent-builder')
   jmh project(':dd-java-agent:instrumentation:iast-instrumenter')
   jmh project(':dd-java-agent:instrumentation:java-lang')
+
+  compileOnly('org.jetbrains:annotations:24.0.0')
+  errorprone('com.uber.nullaway:nullaway:0.10.15')
+  errorprone('com.google.errorprone:error_prone_core:2.23.0')
 }
 
 shadowJar {
@@ -80,7 +100,6 @@ ext {
 tasks.withType(Test).configureEach {
   jvmArgs += ['-Ddd.iast.enabled=true']
 }
-def rootDir = project.rootDir
 spotless {
   java {
     target 'src/**/*.java'
@@ -104,3 +123,16 @@ sourceSets {
     }
   }
 }
+
+tasks.withType(JavaCompile).configureEach {
+  if (name == 'compileJava') {
+    options.errorprone {
+      check("NullAway", CheckSeverity.ERROR)
+      option("NullAway:AnnotatedPackages", "com.datadog.iast")
+      disableAllWarnings = true // only errors for now
+    }
+  } else {
+    // disable null away for test and jmh
+    options.errorprone.enabled = false
+  }
+}

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/Dependencies.java

@@ -0,0 +1,41 @@
+package com.datadog.iast;
+
+import com.datadog.iast.overhead.OverheadController;
+import datadog.trace.api.Config;
+import datadog.trace.util.stacktrace.StackWalker;
+import javax.annotation.Nonnull;
+
+public class Dependencies {
+
+  private final Config config;
+  private final Reporter reporter;
+  private final OverheadController overheadController;
+  private final StackWalker stackWalker;
+
+  public Dependencies(
+      @Nonnull final Config config,
+      @Nonnull final Reporter reporter,
+      @Nonnull final OverheadController overheadController,
+      @Nonnull final StackWalker stackWalker) {
+    this.config = config;
+    this.reporter = reporter;
+    this.overheadController = overheadController;
+    this.stackWalker = stackWalker;
+  }
+
+  public Config getConfig() {
+    return config;
+  }
+
+  public Reporter getReporter() {
+    return reporter;
+  }
+
+  public OverheadController getOverheadController() {
+    return overheadController;
+  }
+
+  public StackWalker getStackWalker() {
+    return stackWalker;
+  }
+}

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/IastRequestContext.java

@@ -18,11 +18,11 @@ public class IastRequestContext implements IastContext, HasMetricCollector {
   private final AtomicBoolean spanDataIsSet;
   private final TaintedObjects taintedObjects;
   private final OverheadContext overheadContext;
-  private final IastMetricCollector collector;
-  private volatile String strictTransportSecurity;
-  private volatile String xContentTypeOptions;
-  private volatile String xForwardedProto;
-  private volatile String contentType;
+  @Nullable private final IastMetricCollector collector;
+  @Nullable private volatile String strictTransportSecurity;
+  @Nullable private volatile String xContentTypeOptions;
+  @Nullable private volatile String xForwardedProto;
+  @Nullable private volatile String contentType;
 
   public IastRequestContext() {
     this(TaintedObjects.acquire(), null);
@@ -33,7 +33,7 @@ public IastRequestContext(final TaintedObjects taintedObjects) {
   }
 
   public IastRequestContext(
-      final TaintedObjects taintedObjects, final IastMetricCollector collector) {
+      final TaintedObjects taintedObjects, @Nullable final IastMetricCollector collector) {
     this.vulnerabilityBatch = new VulnerabilityBatch();
     this.spanDataIsSet = new AtomicBoolean(false);
     this.overheadContext = new OverheadContext();
@@ -45,6 +45,7 @@ public VulnerabilityBatch getVulnerabilityBatch() {
     return vulnerabilityBatch;
   }
 
+  @Nullable
   public String getStrictTransportSecurity() {
     return strictTransportSecurity;
   }
@@ -53,6 +54,7 @@ public void setStrictTransportSecurity(final String strictTransportSecurity) {
     this.strictTransportSecurity = strictTransportSecurity;
   }
 
+  @Nullable
   public String getxContentTypeOptions() {
     return xContentTypeOptions;
   }
@@ -61,6 +63,7 @@ public void setxContentTypeOptions(final String xContentTypeOptions) {
     this.xContentTypeOptions = xContentTypeOptions;
   }
 
+  @Nullable
   public String getxForwardedProto() {
     return xForwardedProto;
   }
@@ -69,6 +72,7 @@ public void setxForwardedProto(final String xForwardedProto) {
     this.xForwardedProto = xForwardedProto;
   }
 
+  @Nullable
   public String getContentType() {
     return contentType;
   }
@@ -111,6 +115,7 @@ public static IastRequestContext get(final RequestContext reqCtx) {
     return asRequestContext(IastContext.Provider.get(reqCtx));
   }
 
+  @Nullable
   private static IastRequestContext asRequestContext(final IastContext ctx) {
     return ctx instanceof IastRequestContext ? (IastRequestContext) ctx : null;
   }

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/IastSystem.java

@@ -1,6 +1,5 @@
 package com.datadog.iast;
 
-import com.datadog.iast.HasDependencies.Dependencies;
 import com.datadog.iast.overhead.OverheadController;
 import com.datadog.iast.propagation.FastCodecModule;
 import com.datadog.iast.propagation.PropagationModuleImpl;
@@ -40,9 +39,9 @@
 import datadog.trace.util.AgentTaskScheduler;
 import datadog.trace.util.stacktrace.StackWalkerFactory;
 import java.util.function.BiFunction;
-import java.util.function.Consumer;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
+import javax.annotation.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -55,7 +54,8 @@ public static void start(final SubscriptionService ss) {
     start(ss, null);
   }
 
-  public static void start(final SubscriptionService ss, OverheadController overheadController) {
+  public static void start(
+      final SubscriptionService ss, @Nullable OverheadController overheadController) {
     final Config config = Config.get();
     if (config.getIastActivation() != ProductActivation.FULLY_ENABLED) {
       LOGGER.debug("IAST is disabled");
@@ -70,46 +70,37 @@ public static void start(final SubscriptionService ss, OverheadController overhe
     final Dependencies dependencies =
         new Dependencies(config, reporter, overheadController, StackWalkerFactory.INSTANCE);
     final boolean addTelemetry = config.getIastTelemetryVerbosity() != Verbosity.OFF;
-    iastModules().forEach(registerModule(dependencies));
+    iastModules(dependencies).forEach(InstrumentationBridge::registerIastModule);
     registerRequestStartedCallback(ss, addTelemetry, dependencies);
     registerRequestEndedCallback(ss, addTelemetry, dependencies);
     registerHeadersCallback(ss);
     registerGrpcServerRequestMessageCallback(ss);
     LOGGER.debug("IAST started");
   }
 
-  private static Consumer<IastModule> registerModule(final Dependencies dependencies) {
-    return module -> {
-      if (module instanceof HasDependencies) {
-        ((HasDependencies) module).registerDependencies(dependencies);
-      }
-      InstrumentationBridge.registerIastModule(module);
-    };
-  }
-
-  private static Stream<IastModule> iastModules() {
+  private static Stream<IastModule> iastModules(final Dependencies dependencies) {
     return Stream.of(
         new StringModuleImpl(),
         new FastCodecModule(),
-        new SqlInjectionModuleImpl(),
-        new PathTraversalModuleImpl(),
-        new CommandInjectionModuleImpl(),
-        new WeakCipherModuleImpl(),
-        new WeakHashModuleImpl(),
-        new LdapInjectionModuleImpl(),
+        new SqlInjectionModuleImpl(dependencies),
+        new PathTraversalModuleImpl(dependencies),
+        new CommandInjectionModuleImpl(dependencies),
+        new WeakCipherModuleImpl(dependencies),
+        new WeakHashModuleImpl(dependencies),
+        new LdapInjectionModuleImpl(dependencies),
         new PropagationModuleImpl(),
-        new HttpResponseHeaderModuleImpl(),
-        new HstsMissingHeaderModuleImpl(),
+        new HttpResponseHeaderModuleImpl(dependencies),
+        new HstsMissingHeaderModuleImpl(dependencies),
         new InsecureCookieModuleImpl(),
         new NoHttpOnlyCookieModuleImpl(),
-        new XContentTypeModuleImpl(),
+        new XContentTypeModuleImpl(dependencies),
         new NoSameSiteCookieModuleImpl(),
-        new SsrfModuleImpl(),
-        new UnvalidatedRedirectModuleImpl(),
-        new WeakRandomnessModuleImpl(),
-        new XPathInjectionModuleImpl(),
-        new TrustBoundaryViolationModuleImpl(),
-        new XssModuleImpl());
+        new SsrfModuleImpl(dependencies),
+        new UnvalidatedRedirectModuleImpl(dependencies),
+        new WeakRandomnessModuleImpl(dependencies),
+        new XPathInjectionModuleImpl(dependencies),
+        new TrustBoundaryViolationModuleImpl(dependencies),
+        new XssModuleImpl(dependencies));
   }
 
   private static void registerRequestStartedCallback(

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/Reporter.java

@@ -30,7 +30,7 @@ public class Reporter {
     this(Config.get(), null);
   }
 
-  public Reporter(final Config config, final AgentTaskScheduler taskScheduler) {
+  public Reporter(final Config config, @Nullable final AgentTaskScheduler taskScheduler) {
     this(
         config.isIastDeduplicationEnabled()
             ? new HashBasedDeduplication(taskScheduler)
@@ -108,11 +108,11 @@ protected static class HashBasedDeduplication implements Predicate<Vulnerability
 
     private final Set<Long> hashes;
 
-    public HashBasedDeduplication(final AgentTaskScheduler taskScheduler) {
+    public HashBasedDeduplication(@Nullable final AgentTaskScheduler taskScheduler) {
       this(DEFAULT_MAX_SIZE, taskScheduler);
     }
 
-    HashBasedDeduplication(final int size, final AgentTaskScheduler taskScheduler) {
+    HashBasedDeduplication(final int size, @Nullable final AgentTaskScheduler taskScheduler) {
       maxSize = size;
       hashes = ConcurrentHashMap.newKeySet(size);
       if (taskScheduler != null) {

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/RequestEndedHandler.java

@@ -3,7 +3,6 @@
 import static com.datadog.iast.IastTag.ANALYZED;
 import static com.datadog.iast.IastTag.SKIPPED;
 
-import com.datadog.iast.HasDependencies.Dependencies;
 import com.datadog.iast.overhead.OverheadController;
 import com.datadog.iast.taint.TaintedObjects;
 import datadog.trace.api.gateway.Flow;

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/RequestStartedHandler.java

@@ -1,6 +1,5 @@
 package com.datadog.iast;
 
-import com.datadog.iast.HasDependencies.Dependencies;
 import com.datadog.iast.overhead.OverheadController;
 import datadog.trace.api.gateway.Flow;
 import java.util.function.Supplier;

dd-java-agent/agent-iast/src/main/java/com/datadog/iast/model/Evidence.java

@@ -17,6 +17,8 @@ public final class Evidence {
   private final transient @Nonnull Context context = new Evidence.Context(4);
 
   /** For deserialization in tests via moshi */
+  @Deprecated
+  @SuppressWarnings({"NullAway", "DataFlowIssue", "unused"})
   private Evidence() {
     this(null, null);
   }
@@ -25,15 +27,17 @@ public Evidence(final String value) {
     this(value, null);
   }
 
-  public Evidence(final String value, final Range[] ranges) {
+  public Evidence(@Nonnull final String value, @Nullable final Range[] ranges) {
     this.value = value;
     this.ranges = ranges;
   }
 
+  @Nonnull
   public String getValue() {
     return value;
   }
 
+  @Nullable
   public Range[] getRanges() {
     return ranges;
   }
@@ -76,6 +80,7 @@ public boolean put(final String key, final Object value) {
       return true;
     }
 
+    @Nullable
     @SuppressWarnings("unchecked")
     public <E> E get(@Nonnull final String key) {
       return (E) context.get(key);