Merge from master

Author: Dave Bartolomeo

change-notes/1.24/analysis-csharp.md

@@ -18,6 +18,7 @@ The following changes in version 1.24 affect C# analysis in all applications.
 | **Query**                    | **Expected impact**    | **Change**                        |
 |------------------------------|------------------------|-----------------------------------|
 | Useless assignment to local variable (`cs/useless-assignment-to-local`) | Fewer false positive results | Results have been removed when the variable is named `_` in a `foreach` statement. | 
+| Potentially dangerous use of non-short-circuit logic (`cs/non-short-circuit`) | Fewer false positive results | Results have been removed when the expression contains an `out` parameter. |
 | Dereferenced variable may be null (`cs/dereferenced-value-may-be-null`) | More results | Results are reported from parameters with a default value of `null`. |
 
 ## Removal of old queries

change-notes/1.24/analysis-javascript.md

@@ -7,7 +7,9 @@
 * Imports with the `.js` extension can now be resolved to a TypeScript file,
   when the import refers to a file generated by TypeScript.
 
-- The analysis of sanitizer guards has improved, leading to fewer false-positive results from the security queries.
+* Imports that rely on path-mappings from a `tsconfig.json` file can now be resolved.
+
+* The analysis of sanitizer guards has improved, leading to fewer false-positive results from the security queries.
 
 * Support for the following frameworks and libraries has been improved:
   - [react](https://www.npmjs.com/package/react)
@@ -18,6 +20,7 @@
   - [Socket.IO](https://socket.io/)
   - [ws](https://github.com/websockets/ws)
   - [WebSocket](https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API)
+  - [Koa](https://www.npmjs.com/package/koa)
 
 ## New queries
 

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowUtil.qll

@@ -6,7 +6,6 @@ private import cpp
 private import semmle.code.cpp.dataflow.internal.FlowVar
 private import semmle.code.cpp.models.interfaces.DataFlow
 private import semmle.code.cpp.controlflow.Guards
-private import semmle.code.cpp.valuenumbering.GlobalValueNumbering
 
 cached
 private newtype TNode =
@@ -689,9 +688,9 @@ class BarrierGuard extends GuardCondition {
 
   /** Gets a node guarded by this guard. */
   final ExprNode getAGuardedNode() {
-    exists(GVN value, boolean branch |
-      result.getExpr() = value.getAnExpr() and
-      this.checks(value.getAnExpr(), branch) and
+    exists(SsaDefinition def, Variable v, boolean branch |
+      result.getExpr() = def.getAUse(v) and
+      this.checks(def.getAUse(v), branch) and
       this.controls(result.getExpr().getBasicBlock(), branch)
     )
   }

cpp/ql/src/semmle/code/cpp/ir/dataflow/DefaultTaintTracking.qll

@@ -151,6 +151,22 @@ private predicate instructionTaintStep(Instruction i1, Instruction i2) {
   // from `a`.
   i2.(PointerAddInstruction).getLeft() = i1
   or
+  // Until we have from through indirections across calls, we'll take flow out
+  // of the parameter and into its indirection.
+  exists(IRFunction f, Parameter parameter |
+    i1 = getInitializeParameter(f, parameter) and
+    i2 = getInitializeIndirection(f, parameter)
+  )
+  or
+  // Until we have flow through indirections across calls, we'll take flow out
+  // of the indirection and into the argument.
+  // When we get proper flow through indirections across calls, this code can be
+  // moved to `adjusedSink` or possibly into the `DataFlow::ExprNode` class.
+  exists(ReadSideEffectInstruction read |
+    read.getAnOperand().(SideEffectOperand).getAnyDef() = i1 and
+    read.getArgumentDef() = i2
+  )
+  or
   // Flow from argument to return value
   i2 =
     any(CallInstruction call |
@@ -176,6 +192,18 @@ private predicate instructionTaintStep(Instruction i1, Instruction i2) {
     )
 }
 
+pragma[noinline]
+private InitializeIndirectionInstruction getInitializeIndirection(IRFunction f, Parameter p) {
+  result.getParameter() = p and
+  result.getEnclosingIRFunction() = f
+}
+
+pragma[noinline]
+private InitializeParameterInstruction getInitializeParameter(IRFunction f, Parameter p) {
+  result.getParameter() = p and
+  result.getEnclosingIRFunction() = f
+}
+
 /**
  * Get an instruction that goes into argument `argumentIndex` of `call`. This
  * can be either directly or through one pointer indirection.
@@ -273,23 +301,6 @@ private Element adjustedSink(DataFlow::Node sink) {
   // For compatibility, send flow into a `NotExpr` even if it's part of a
   // short-circuiting condition and thus might get skipped.
   result.(NotExpr).getOperand() = sink.asExpr()
-  or
-  // For compatibility, send flow from argument read side effects to their
-  // corresponding argument expression
-  exists(IndirectReadSideEffectInstruction read |
-    read.getAnOperand().(SideEffectOperand).getAnyDef() = sink.asInstruction() and
-    read.getArgumentDef().getUnconvertedResultExpression() = result
-  )
-  or
-  exists(BufferReadSideEffectInstruction read |
-    read.getAnOperand().(SideEffectOperand).getAnyDef() = sink.asInstruction() and
-    read.getArgumentDef().getUnconvertedResultExpression() = result
-  )
-  or
-  exists(SizedBufferReadSideEffectInstruction read |
-    read.getAnOperand().(SideEffectOperand).getAnyDef() = sink.asInstruction() and
-    read.getArgumentDef().getUnconvertedResultExpression() = result
-  )
 }
 
 predicate tainted(Expr source, Element tainted) {

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/internal/AliasedSSA.qll

@@ -26,7 +26,7 @@ private predicate hasResultMemoryAccess(
     type = languageType.getIRType() and
     isIndirectOrBufferMemoryAccess(instr.getResultMemoryAccess()) and
     (if instr.hasResultMayMemoryAccess() then isMayAccess = true else isMayAccess = false) and
-    if exists(type.getByteSize())
+    if type.getByteSize() > 0
     then endBitOffset = Ints::add(startBitOffset, Ints::mul(type.getByteSize(), 8))
     else endBitOffset = Ints::unknown()
   )
@@ -43,7 +43,7 @@ private predicate hasOperandMemoryAccess(
     type = languageType.getIRType() and
     isIndirectOrBufferMemoryAccess(operand.getMemoryAccess()) and
     (if operand.hasMayReadMemoryAccess() then isMayAccess = true else isMayAccess = false) and
-    if exists(type.getByteSize())
+    if type.getByteSize() > 0
     then endBitOffset = Ints::add(startBitOffset, Ints::mul(type.getByteSize(), 8))
     else endBitOffset = Ints::unknown()
   )