Merge pull request #17901 from aschackmull/java/allowlist-sanitizer

Java: Add a default taint sanitizer for contains-checks on lists of constants

Author: aschackmull

java/ql/lib/change-notes/2024-11-04-list-of-constants-sanitizer.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Calling `coll.contains(x)` is now a taint sanitizer (for any query) for the value `x`, where `coll` is a collection of constants.

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

@@ -28,6 +28,7 @@ private module Frameworks {
   private import semmle.code.java.frameworks.ThreadLocal
   private import semmle.code.java.frameworks.ratpack.RatpackExec
   private import semmle.code.java.frameworks.stapler.Stapler
+  private import semmle.code.java.security.ListOfConstantsSanitizer
 }
 
 /**
@@ -189,3 +190,8 @@ private class NumberTaintPreservingCallable extends TaintPreservingCallable {
  * map-key and map-value content, so that e.g. a tainted `Map` is assumed to have tainted keys and values.
  */
 abstract class TaintInheritingContent extends DataFlow::Content { }
+
+/**
+ * A sanitizer in all global taint flow configurations but not in local taint.
+ */
+abstract class DefaultTaintSanitizer extends DataFlow::Node { }

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

@@ -13,46 +13,55 @@ private import semmle.code.java.dispatch.VirtualDispatch
 private import semmle.code.java.dataflow.internal.BaseSSA
 private import semmle.code.java.controlflow.Guards
 private import codeql.typeflow.TypeFlow
+private import codeql.typeflow.UniversalFlow as UniversalFlow
 
-private module Input implements TypeFlowInput<Location> {
-  private newtype TTypeFlowNode =
+/** Gets `t` if it is a `RefType` or the boxed type if `t` is a primitive type. */
+private RefType boxIfNeeded(J::Type t) {
+  t.(PrimitiveType).getBoxedType() = result or
+  result = t
+}
+
+/** Provides the input types and predicates for instantiation of `UniversalFlow`. */
+module FlowStepsInput implements UniversalFlow::UniversalFlowInput<Location> {
+  private newtype TFlowNode =
     TField(Field f) { not f.getType() instanceof PrimitiveType } or
     TSsa(BaseSsaVariable ssa) { not ssa.getSourceVariable().getType() instanceof PrimitiveType } or
     TExpr(Expr e) or
     TMethod(Method m) { not m.getReturnType() instanceof PrimitiveType }
 
-  /** Gets `t` if it is a `RefType` or the boxed type if `t` is a primitive type. */
-  private RefType boxIfNeeded(J::Type t) {
-    t.(PrimitiveType).getBoxedType() = result or
-    result = t
-  }
-
   /**
    * A `Field`, `BaseSsaVariable`, `Expr`, or `Method`.
    */
-  class TypeFlowNode extends TTypeFlowNode {
+  class FlowNode extends TFlowNode {
+    /** Gets a textual representation of this element. */
     string toString() {
       result = this.asField().toString() or
       result = this.asSsa().toString() or
       result = this.asExpr().toString() or
       result = this.asMethod().toString()
     }
 
+    /** Gets the source location for this element. */
     Location getLocation() {
       result = this.asField().getLocation() or
       result = this.asSsa().getLocation() or
       result = this.asExpr().getLocation() or
       result = this.asMethod().getLocation()
     }
 
+    /** Gets the field corresponding to this node, if any. */
     Field asField() { this = TField(result) }
 
+    /** Gets the SSA variable corresponding to this node, if any. */
     BaseSsaVariable asSsa() { this = TSsa(result) }
 
+    /** Gets the expression corresponding to this node, if any. */
     Expr asExpr() { this = TExpr(result) }
 
+    /** Gets the method corresponding to this node, if any. */
     Method asMethod() { this = TMethod(result) }
 
+    /** Gets the type of this node. */
     RefType getType() {
       result = this.asField().getType() or
       result = this.asSsa().getSourceVariable().getType() or
@@ -61,8 +70,6 @@ private module Input implements TypeFlowInput<Location> {
     }
   }
 
-  class Type = RefType;
-
   private SrcCallable viableCallable_v1(Call c) {
     result = viableImpl_v1(c)
     or
@@ -88,7 +95,7 @@ private module Input implements TypeFlowInput<Location> {
    *
    * For a given `n2`, this predicate must include all possible `n1` that can flow to `n2`.
    */
-  predicate step(TypeFlowNode n1, TypeFlowNode n2) {
+  predicate step(FlowNode n1, FlowNode n2) {
     n2.asExpr().(ChooseExpr).getAResultExpr() = n1.asExpr()
     or
     exists(Field f, Expr e |
@@ -134,7 +141,7 @@ private module Input implements TypeFlowInput<Location> {
   /**
    * Holds if `null` is the only value that flows to `n`.
    */
-  predicate isNullValue(TypeFlowNode n) {
+  predicate isNullValue(FlowNode n) {
     n.asExpr() instanceof NullLiteral
     or
     exists(LocalVariableDeclExpr decl |
@@ -144,11 +151,21 @@ private module Input implements TypeFlowInput<Location> {
     )
   }
 
-  predicate isExcludedFromNullAnalysis(TypeFlowNode n) {
+  predicate isExcludedFromNullAnalysis(FlowNode n) {
     // Fields that are never assigned a non-null value are probably set by
     // reflection and are thus not always null.
     exists(n.asField())
   }
+}
+
+private module Input implements TypeFlowInput<Location> {
+  import FlowStepsInput
+
+  class TypeFlowNode = FlowNode;
+
+  predicate isExcludedFromNullAnalysis = FlowStepsInput::isExcludedFromNullAnalysis/1;
+
+  class Type = RefType;
 
   predicate exactTypeBase(TypeFlowNode n, RefType t) {
     exists(ClassInstanceExpr e |

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

@@ -38,6 +38,7 @@ class BaseSsaSourceVariable extends TBaseSsaSourceVariable {
   /** Gets the `Callable` in which this `BaseSsaSourceVariable` is defined. */
   Callable getEnclosingCallable() { this = TLocalVar(result, _) }
 
+  /** Gets a textual representation of this element. */
   string toString() {
     exists(LocalScopeVariable v, Callable c | this = TLocalVar(c, v) |
       if c = v.getCallable()
@@ -46,6 +47,7 @@ class BaseSsaSourceVariable extends TBaseSsaSourceVariable {
     )
   }
 
+  /** Gets the source location for this element. */
   Location getLocation() {
     exists(LocalScopeVariable v | this = TLocalVar(_, v) and result = v.getLocation())
   }
@@ -482,8 +484,10 @@ class BaseSsaVariable extends TBaseSsaVariable {
     this = TSsaEntryDef(_, result)
   }
 
+  /** Gets a textual representation of this element. */
   string toString() { none() }
 
+  /** Gets the source location for this element. */
   Location getLocation() { result = this.getCfgNode().getLocation() }
 
   /** Gets the `BasicBlock` in which this SSA variable is defined. */

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

@@ -161,6 +161,7 @@ private module Cached {
    */
   cached
   predicate defaultTaintSanitizer(DataFlow::Node node) {
+    node instanceof DefaultTaintSanitizer or
     // Ignore paths through test code.
     node.getEnclosingCallable().getDeclaringType() instanceof NonSecurityTestClass or
     node.asExpr() instanceof ValidatedVariableAccess