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tamasvajktamasvajk
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C#: Add flow summary for 'Task.ConfigureAwait()'
1 parent a1b59e2 commit 342a711

4 files changed

Lines changed: 114 additions & 0 deletions

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‎csharp/ql/src/semmle/code/csharp/dataflow/LibraryTypeDataFlow.qll‎

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Original file line numberDiff line numberDiff line change
@@ -1843,6 +1843,53 @@ class SystemThreadingTasksTaskTFlow extends LibraryTypeDataFlow, SystemThreading
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sinkAp =
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AccessPath::field(any(SystemRuntimeCompilerServicesTaskAwaiterStruct s)
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.getUnderlyingTaskField())
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or
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// var awaitable = task.ConfigureAwait(false); // <-- new ConfiguredTaskAwaitable<>(task, false)
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// // m_configuredTaskAwaiter = new ConfiguredTaskAwaiter(task, false)
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// // m_task = task
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// var awaiter = awaitable.GetAwaiter();
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// var result = awaiter.GetResult();
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m = this.getConfigureAwaitMethod() and
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source = TCallableFlowSourceQualifier() and
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sourceAp = AccessPath::empty() and
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sink = TCallableFlowSinkReturn() and
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sinkAp =
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AccessPath::cons(any(FieldContent fc |
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fc.getField() =
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any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct t)
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.getUnderlyingAwaiterField()
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),
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AccessPath::field(any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct s
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).getUnderlyingTaskField()))
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}
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override predicate requiresAccessPath(Content head, AccessPath tail) {
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head.(FieldContent).getField() =
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any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct t).getUnderlyingAwaiterField() and
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tail =
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AccessPath::field(any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct s
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).getUnderlyingTaskField())
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}
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}
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/** Data flow for `System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>`. */
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private class SystemRuntimeCompilerServicesConfiguredTaskAwaitableTFlow extends LibraryTypeDataFlow,
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SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct {
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override predicate callableFlow(
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CallableFlowSource source, AccessPath sourceAp, CallableFlowSink sink, AccessPath sinkAp,
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SourceDeclarationCallable c, boolean preservesValue
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) {
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// var awaitable = task.ConfigureAwait(false);
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// var awaiter = awaitable.GetAwaiter(); // <-- awaitable.m_configuredTaskAwaiter
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// var result = awaiter.GetResult();
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c = this.getGetAwaiterMethod() and
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source = TCallableFlowSourceQualifier() and
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sourceAp =
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AccessPath::field(any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct s)
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.getUnderlyingAwaiterField()) and
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sink = TCallableFlowSinkReturn() and
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sinkAp = AccessPath::empty() and
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preservesValue = true
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}
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}
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@@ -1950,6 +1997,32 @@ class SystemRuntimeCompilerServicesTaskAwaiterFlow extends LibraryTypeDataFlow,
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}
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}
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/** Data flow for `System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>.ConfiguredTaskAwaiter`. */
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class SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterFlow extends LibraryTypeDataFlow,
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SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct {
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override predicate callableFlow(
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CallableFlowSource source, AccessPath sourceAp, CallableFlowSink sink, AccessPath sinkAp,
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SourceDeclarationCallable c, boolean preservesValue
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) {
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// var awaitable = task.ConfigureAwait(false);
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// var awaiter = awaitable.GetAwaiter();
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// var result = awaiter.GetResult(); // <-- task.Result
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preservesValue = true and
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c = this.getGetResultMethod() and
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source = TCallableFlowSourceQualifier() and
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sourceAp =
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AccessPath::cons(any(FieldContent fc | fc.getField() = this.getUnderlyingTaskField()),
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AccessPath::property(any(SystemThreadingTasksTaskTClass t).getResultProperty())) and
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sink = TCallableFlowSinkReturn() and
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sinkAp = AccessPath::empty()
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}
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override predicate requiresAccessPath(Content head, AccessPath tail) {
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head.(FieldContent).getField() = this.getUnderlyingTaskField() and
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tail = AccessPath::property(any(SystemThreadingTasksTaskTClass t).getResultProperty())
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}
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}
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/** Data flow for `System.Text.Encoding`. */
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library class SystemTextEncodingFlow extends LibraryTypeDataFlow, SystemTextEncodingClass {
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override predicate callableFlow(

‎csharp/ql/src/semmle/code/csharp/frameworks/system/runtime/CompilerServices.qll‎

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Original file line numberDiff line numberDiff line change
@@ -28,3 +28,38 @@ class SystemRuntimeCompilerServicesTaskAwaiterStruct extends SystemRuntimeCompil
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/** Gets the field that stores the underlying task. */
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Field getUnderlyingTaskField() { result = this.getAField() and result.hasName("m_task") }
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}
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/** The `System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>` struct. */
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class SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct extends SystemRuntimeCompilerServicesNamespaceUnboundGenericStruct {
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SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct() {
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this.hasName("ConfiguredTaskAwaitable<>")
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}
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/** Gets the `GetAwaiter` method. */
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Method getGetAwaiterMethod() { result = this.getAMethod("GetAwaiter") }
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/** Gets the field that stores the underlying awaiter. */
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Field getUnderlyingAwaiterField() {
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result = this.getAField() and result.hasName("m_configuredTaskAwaiter")
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}
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}
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/** An unbound generic struct in the `System.Runtime.CompilerServices` namespace. */
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class SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStructStruct extends Struct {
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SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStructStruct() {
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this = any(SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStruct n).getANestedType()
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}
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}
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/** The `System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>.ConfiguredTaskAwaiter` struct. */
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class SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct extends SystemRuntimeCompilerServicesConfiguredTaskAwaitableTStructStruct {
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SystemRuntimeCompilerServicesConfiguredTaskAwaitableTConfiguredTaskAwaiterStruct() {
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this.hasName("ConfiguredTaskAwaiter")
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}
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/** Gets the `GetResult` method. */
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Method getGetResultMethod() { result = this.getAMethod("GetResult") }
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/** Gets the field that stores the underlying task. */
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Field getUnderlyingTaskField() { result = this.getAField() and result.hasName("m_task") }
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}

‎csharp/ql/src/semmle/code/csharp/frameworks/system/threading/Tasks.qll‎

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Original file line numberDiff line numberDiff line change
@@ -41,4 +41,7 @@ class SystemThreadingTasksTaskTClass extends SystemThreadingTasksUnboundGenericC
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/** Gets the `GetAwaiter` method. */
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Method getGetAwaiterMethod() { result = this.getAMethod("GetAwaiter") }
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/** Gets the `ConfigureAwait` method. */
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Method getConfigureAwaitMethod() { result = this.getAMethod("ConfigureAwait") }
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}

‎csharp/ql/test/library-tests/dataflow/library/LibraryTypeDataFlow.expected‎

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Original file line numberDiff line numberDiff line change
@@ -1776,6 +1776,8 @@ callableFlowAccessPath
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| System.Resources.ResourceReader.GetEnumerator() | qualifier [[]] -> return [Current] | true |
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| System.Resources.ResourceSet.GetEnumerator() | qualifier [[]] -> return [Current] | true |
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| System.Runtime.CompilerServices.ConditionalWeakTable<,>.GetEnumerator() | qualifier [[]] -> return [Current] | true |
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| System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>.ConfiguredTaskAwaiter.GetResult() | qualifier [m_task, Result] -> return [<empty>] | true |
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| System.Runtime.CompilerServices.ConfiguredTaskAwaitable<>.GetAwaiter() | qualifier [m_configuredTaskAwaiter] -> return [<empty>] | true |
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| System.Runtime.CompilerServices.ReadOnlyCollectionBuilder<>.Add(T) | argument 0 [<empty>] -> qualifier [[]] | true |
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| System.Runtime.CompilerServices.ReadOnlyCollectionBuilder<>.Add(object) | argument 0 [<empty>] -> qualifier [[]] | true |
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| System.Runtime.CompilerServices.ReadOnlyCollectionBuilder<>.CopyTo(Array, int) | qualifier [[]] -> argument 0 [[]] | true |
@@ -1927,6 +1929,7 @@ callableFlowAccessPath
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| System.Threading.Tasks.Task.WhenAll<TResult>(params Task<TResult>[]) | argument 0 [[], Result] -> return [Result, []] | true |
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| System.Threading.Tasks.Task.WhenAny<TResult>(IEnumerable<Task<TResult>>) | argument 0 [[], Result] -> return [Result, []] | true |
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| System.Threading.Tasks.Task.WhenAny<TResult>(params Task<TResult>[]) | argument 0 [[], Result] -> return [Result, []] | true |
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| System.Threading.Tasks.Task<>.ConfigureAwait(bool) | qualifier [<empty>] -> return [m_configuredTaskAwaiter, m_task] | true |
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| System.Threading.Tasks.Task<>.ContinueWith<TNewResult>(Func<Task<>, Object, TNewResult>, object) | output from argument 0 [<empty>] -> return [Result] | true |
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| System.Threading.Tasks.Task<>.ContinueWith<TNewResult>(Func<Task<>, Object, TNewResult>, object, CancellationToken) | output from argument 0 [<empty>] -> return [Result] | true |
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| System.Threading.Tasks.Task<>.ContinueWith<TNewResult>(Func<Task<>, Object, TNewResult>, object, CancellationToken, TaskContinuationOptions, TaskScheduler) | output from argument 0 [<empty>] -> return [Result] | true |

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