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Merge pull request #13772 from atorralba/atorralba/java/inputstream-wrapper-read-step
Java: Add taint steps for InputStream wrappers
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‎java/ql/lib/change-notes/2023-07-19-inputstream-wrapper-steps.md‎

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---
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category: minorAnalysis
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---
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* Added more dataflow steps for `java.io.InputStream`s that wrap other `java.io.InputStream`s.

‎java/ql/lib/semmle/code/java/JDK.qll‎

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@@ -177,6 +177,11 @@ class TypeObjectInputStream extends RefType {
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TypeObjectInputStream() { this.hasQualifiedName("java.io", "ObjectInputStream") }
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}
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/** The class `java.io.InputStream`. */
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class TypeInputStream extends RefType {
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TypeInputStream() { this.hasQualifiedName("java.io", "InputStream") }
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}
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/** The class `java.nio.file.Paths`. */
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class TypePaths extends Class {
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TypePaths() { this.hasQualifiedName("java.nio.file", "Paths") }

‎java/ql/lib/semmle/code/java/dataflow/FlowSteps.qll‎

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@@ -20,11 +20,11 @@ private module Frameworks {
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private import semmle.code.java.frameworks.Guice
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private import semmle.code.java.frameworks.IoJsonWebToken
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private import semmle.code.java.frameworks.jackson.JacksonSerializability
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private import semmle.code.java.frameworks.InputStream
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private import semmle.code.java.frameworks.Properties
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private import semmle.code.java.frameworks.Protobuf
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private import semmle.code.java.frameworks.ratpack.RatpackExec
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private import semmle.code.java.frameworks.stapler.Stapler
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private import semmle.code.java.JDK
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}
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/**

‎java/ql/lib/semmle/code/java/dataflow/RangeAnalysis.qll‎

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@@ -757,7 +757,7 @@ private predicate baseBound(Expr e, int b, boolean upper) {
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or
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exists(Method read |
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e.(MethodAccess).getMethod().overrides*(read) and
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read.getDeclaringType().hasQualifiedName("java.io", "InputStream") and
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read.getDeclaringType() instanceof TypeInputStream and
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read.hasName("read") and
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read.getNumberOfParameters() = 0
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|

‎java/ql/lib/semmle/code/java/dataflow/internal/TaintTrackingUtil.qll‎

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@@ -239,7 +239,7 @@ private class BulkData extends RefType {
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this.(Array).getElementType().(PrimitiveType).hasName(["byte", "char"])
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or
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exists(RefType t | this.getASourceSupertype*() = t |
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t.hasQualifiedName("java.io", "InputStream") or
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t instanceof TypeInputStream or
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t.hasQualifiedName("java.nio", "ByteBuffer") or
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t.hasQualifiedName("java.lang", "Readable") or
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t.hasQualifiedName("java.io", "DataInput") or
@@ -259,7 +259,7 @@ private class BulkData extends RefType {
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private predicate inputStreamWrapper(Constructor c, int argi) {
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not c.fromSource() and
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c.getParameterType(argi) instanceof BulkData and
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c.getDeclaringType().getASourceSupertype+().hasQualifiedName("java.io", "InputStream")
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c.getDeclaringType().getASourceSupertype+() instanceof TypeInputStream
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}
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/** An object construction that preserves the data flow status of any of its arguments. */

‎java/ql/lib/semmle/code/java/dispatch/VirtualDispatch.qll‎

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@@ -102,7 +102,7 @@ private module Dispatch {
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or
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t instanceof Interface and not t.fromSource()
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or
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t.hasQualifiedName("java.io", "InputStream")
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t instanceof TypeInputStream
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or
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t.hasQualifiedName("java.io", "Serializable")
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or

‎java/ql/lib/semmle/code/java/frameworks/InputStream.qll‎

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/** Provides definitions related to `java.io.InputStream`. */
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import java
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private import semmle.code.java.dataflow.DataFlow
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private import semmle.code.java.dataflow.FlowSteps
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private import semmle.code.java.dataflow.SSA
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private import semmle.code.java.dataflow.TaintTracking
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/**
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* A jump taint step from an update of the `bytes[]` parameter in an override of the `InputStream.read` method
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* to a class instance expression of the type extending `InputStream`.
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*
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* This models how a subtype of `InputStream` could be tainted by the definition of its methods, which will
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* normally only happen in nested classes.
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*/
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private class InputStreamWrapperCapturedJumpStep extends AdditionalTaintStep {
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override predicate step(DataFlow::Node n1, DataFlow::Node n2) {
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exists(InputStreamRead m, NestedClass wrapper |
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m.getDeclaringType() = wrapper and
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wrapper.getASourceSupertype+() instanceof TypeInputStream
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|
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n1.(DataFlow::PostUpdateNode).getPreUpdateNode().asExpr() = m.getParameter(0).getAnAccess() and
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n2.asExpr()
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.(ClassInstanceExpr)
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.getConstructedType()
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.getASourceSupertype*()
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.getSourceDeclaration() = wrapper
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)
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}
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}
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/**
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* A local taint step from the definition of a captured variable, the capturer of which
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* updates the `bytes[]` parameter in an override of the `InputStream.read` method,
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* to a class instance expression of the type extending `InputStream`.
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*
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* This models how a subtype of `InputStream` could be tainted by capturing tainted variables in
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* the definition of its methods.
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*/
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private class InputStreamWrapperCapturedLocalStep extends AdditionalTaintStep {
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override predicate step(DataFlow::Node n1, DataFlow::Node n2) {
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exists(InputStreamRead m, NestedClass wrapper, SsaVariable captured, SsaImplicitInit capturer |
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wrapper.getASourceSupertype+() instanceof TypeInputStream and
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m.getDeclaringType() = wrapper and
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capturer.captures(captured) and
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TaintTracking::localTaint(DataFlow::exprNode(capturer.getAFirstUse()),
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any(DataFlow::PostUpdateNode pun |
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pun.getPreUpdateNode().asExpr() = m.getParameter(0).getAnAccess()
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)) and
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n2.asExpr()
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.(ClassInstanceExpr)
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.getConstructedType()
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.getASourceSupertype*()
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.getSourceDeclaration() = wrapper
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|
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n1.asExpr() = captured.(SsaExplicitUpdate).getDefiningExpr().(VariableAssign).getSource()
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or
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captured.(SsaImplicitInit).isParameterDefinition(n1.asParameter())
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)
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}
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}
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/**
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* A taint step from an `InputStream` argument of the constructor of an `InputStream` subtype
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* to the call of the constructor, only if the argument is assigned to a class field.
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*
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* This models how it's assumed that an `InputStream` wrapper is tainted by the wrapped stream,
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* and is a workaround to low `fieldFlowBranchLimit`s in dataflow configurations.
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*/
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private class InputStreamWrapperConstructorStep extends AdditionalTaintStep {
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override predicate step(DataFlow::Node n1, DataFlow::Node n2) {
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exists(ClassInstanceExpr cc, Argument a, AssignExpr ae, int pos |
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cc.getConstructedType().getASourceSupertype+() instanceof TypeInputStream and
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cc.getArgument(pragma[only_bind_into](pos)) = a and
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cc.getCallee().getParameter(pragma[only_bind_into](pos)).getAnAccess() = ae.getRhs() and
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ae.getDest().(FieldWrite).getField().getType().(RefType).getASourceSupertype*() instanceof
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TypeInputStream
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|
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n1.asExpr() = a and
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n2.asExpr() = cc
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)
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}
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}
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private class InputStreamRead extends Method {
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InputStreamRead() {
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this.hasName("read") and
88+
this.getDeclaringType().getASourceSupertype*() instanceof TypeInputStream
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}
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}

‎java/ql/lib/semmle/code/java/frameworks/javaee/ejb/EJBRestrictions.qll‎

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@@ -317,7 +317,7 @@ class SystemSetInputStreamMethod extends Method {
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SystemSetInputStreamMethod() {
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this.hasName("setIn") and
319319
this.getNumberOfParameters() = 1 and
320-
this.getParameter(0).getType().(RefType).hasQualifiedName("java.io", "InputStream") and
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this.getParameter(0).getType() instanceof TypeInputStream and
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this.getDeclaringType()
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.getAnAncestor()
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.getSourceDeclaration()

‎java/ql/lib/semmle/code/java/frameworks/spring/SpringController.qll‎

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@@ -237,7 +237,7 @@ class SpringRequestMappingParameter extends Parameter {
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private predicate isExplicitlyTaintedInput() {
239239
// InputStream or Reader parameters allow access to the body of a request
240-
this.getType().(RefType).getAnAncestor().hasQualifiedName("java.io", "InputStream") or
240+
this.getType().(RefType).getAnAncestor() instanceof TypeInputStream or
241241
this.getType().(RefType).getAnAncestor().hasQualifiedName("java.io", "Reader") or
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// The SpringServletInputAnnotations allow access to the URI, request parameters, cookie values and the body of the request
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this.getAnAnnotation() instanceof SpringServletInputAnnotation or

‎java/ql/test/library-tests/dataflow/stream-read/A.java‎

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import java.io.InputStream;
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import java.io.IOException;
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public class A {
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private static InputStream source() {
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return null;
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}
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private static void sink(Object s) {}
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static class MyStream extends InputStream {
13+
private InputStream wrapped;
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MyStream(InputStream wrapped) {
16+
this.wrapped = wrapped;
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}
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19+
@Override
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public int read() throws IOException {
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return 0;
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}
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@Override
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public int read(byte[] b) throws IOException {
26+
return wrapped.read(b);
27+
}
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}
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public static void testSeveralWrappers() {
31+
InputStream src = source();
32+
InputStream wrapper1 = new MyStream(src);
33+
sink(wrapper1); // $ hasTaintFlow
34+
InputStream wrapper2 = new MyStream(wrapper1);
35+
sink(wrapper2); // $ hasTaintFlow
36+
InputStream wrapper3 = new MyStream(wrapper2);
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sink(wrapper3); // $ hasTaintFlow
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InputStream wrapper4 = new InputStream() {
40+
@Override
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public int read() throws IOException {
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return 0;
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}
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@Override
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public int read(byte[] b) throws IOException {
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return wrapper3.read(b);
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49+
}
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};
51+
sink(wrapper4); // $ hasTaintFlow
52+
}
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public static void testAnonymous() throws Exception {
55+
InputStream wrapper = new InputStream() {
56+
@Override
57+
public int read() throws IOException {
58+
return 0;
59+
}
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61+
@Override
62+
public int read(byte[] b) throws IOException {
63+
InputStream in = source();
64+
return in.read(b);
65+
}
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};
67+
sink(wrapper); // $ hasTaintFlow
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}
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public static void testAnonymousVarCapture() throws Exception {
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InputStream in = source();
72+
InputStream wrapper = new InputStream() {
73+
@Override
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public int read() throws IOException {
75+
return 0;
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}
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@Override
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public int read(byte[] b) throws IOException {
80+
return in.read(b);
81+
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}
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};
84+
sink(wrapper); // $ hasTaintFlow
85+
}
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87+
public static InputStream wrapStream(InputStream in) {
88+
return new InputStream() {
89+
@Override
90+
public int read() throws IOException {
91+
return 0;
92+
}
93+
94+
@Override
95+
public int read(byte[] b) throws IOException {
96+
return in.read(b);
97+
}
98+
};
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}
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101+
public static void testWrapCall() {
102+
sink(wrapStream(null)); // $ SPURIOUS: hasTaintFlow
103+
sink(wrapStream(source())); // $ hasTaintFlow
104+
}
105+
106+
public static void testLocal() {
107+
108+
class LocalInputStream extends InputStream {
109+
@Override
110+
public int read() throws IOException {
111+
return 0;
112+
}
113+
114+
@Override
115+
public int read(byte[] b) throws IOException {
116+
InputStream in = source();
117+
return in.read(b);
118+
}
119+
}
120+
sink(new LocalInputStream()); // $ hasTaintFlow
121+
}
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123+
public static void testLocalVarCapture() {
124+
InputStream in = source();
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126+
class LocalInputStream extends InputStream {
127+
@Override
128+
public int read() throws IOException {
129+
return 0;
130+
}
131+
132+
@Override
133+
public int read(byte[] b) throws IOException {
134+
return in.read(b);
135+
}
136+
}
137+
sink(new LocalInputStream()); // $ hasTaintFlow
138+
}
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}

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