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michaelnebelmichaelnebel
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Merge pull request #8348 from michaelnebel/csharp/externalapi-telemetry
C#: ExternalAPI implementation for Telemetry.
2 parents 146318d + db7abb4 commit 27b1d1e

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‎csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

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@@ -964,6 +964,9 @@ class ArgumentNode extends Node instanceof ArgumentNodeImpl {
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final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
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super.argumentOf(call, pos)
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}
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/** Gets the call in which this node is an argument. */
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DataFlowCall getCall() { this.argumentOf(result, _) }
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}
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abstract private class ArgumentNodeImpl extends Node {
@@ -2035,19 +2038,20 @@ abstract class SyntheticField extends string {
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*/
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predicate containerContent(DataFlow::Content c) { c instanceof DataFlow::ElementContent }
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/** Gets the string representation of the parameters of `c`. */
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string parameterQualifiedTypeNamesToString(DataFlowCallable c) {
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result =
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concat(Parameter p, int i |
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p = c.getParameter(i)
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|
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p.getType().getQualifiedName(), "," order by i
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)
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}
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/**
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* A module containing predicates related to generating models as data.
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*/
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module Csv {
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private string parameterQualifiedTypeNamesToString(DataFlowCallable c) {
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result =
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concat(Parameter p, int i |
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p = c.getParameter(i)
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|
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p.getType().getQualifiedName(), "," order by i
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)
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}
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/** Holds if the summary should apply for all overrides of `c`. */
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predicate isBaseCallableOrPrototype(DataFlowCallable c) {
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c.getDeclaringType() instanceof Interface

‎csharp/ql/src/Telemetry/ExternalApi.qll

Lines changed: 109 additions & 0 deletions
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@@ -0,0 +1,109 @@
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/** Provides classes and predicates related to handling APIs from external libraries. */
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import semmle.code.csharp.dataflow.DataFlow
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private import semmle.code.csharp.dataflow.ExternalFlow
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private import semmle.code.csharp.dataflow.FlowSummary
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private import semmle.code.csharp.dataflow.internal.DataFlowImplCommon as DataFlowImplCommon
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private import semmle.code.csharp.dataflow.internal.DataFlowPrivate
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private import semmle.code.csharp.dataflow.internal.DataFlowDispatch as DataFlowDispatch
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private import semmle.code.csharp.dataflow.TaintTracking
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private import semmle.code.csharp.dataflow.internal.TaintTrackingPrivate
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private import semmle.code.csharp.security.dataflow.flowsources.Remote
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/**
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* A test library.
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*/
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class TestLibrary extends RefType {
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TestLibrary() {
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this.getNamespace()
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.getName()
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.matches(["NUnit.Framework%", "Xunit%", "Microsoft.VisualStudio.TestTools.UnitTesting%"])
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}
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}
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/**
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* An external API from either the C# Standard Library or a 3rd party library.
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*/
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class ExternalApi extends DataFlowDispatch::DataFlowCallable {
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ExternalApi() { this.fromLibrary() }
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/**
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* Gets the unbound type, name and parameter types of this API.
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*/
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private string getSignature() {
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result =
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this.getDeclaringType().getUnboundDeclaration() + "." + this.getName() + "(" +
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parameterQualifiedTypeNamesToString(this) + ")"
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}
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/**
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* Gets the namespace of this API.
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*/
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private string getNamespace() { this.getDeclaringType().hasQualifiedName(result, _) }
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/**
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* Gets the assembly file name containing this API.
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*/
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private string getAssembly() { result = this.getFile().getBaseName() }
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/**
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* Gets the assembly file name and namespace of this API.
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*/
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string getInfoPrefix() { result = this.getAssembly() + "#" + this.getNamespace() }
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/**
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* Gets the assembly file name, namespace and signature of this API.
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*/
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string getInfo() { result = this.getInfoPrefix() + "#" + this.getSignature() }
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/** Gets a call to this API callable. */
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DispatchCall getACall() {
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this = result.getADynamicTarget().getUnboundDeclaration()
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or
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this = result.getAStaticTarget().getUnboundDeclaration()
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}
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/** Gets a node that is an input to a call to this API. */
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private ArgumentNode getAnInput() {
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result.getCall().(DataFlowDispatch::NonDelegateDataFlowCall).getDispatchCall() = this.getACall()
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}
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/** Gets a node that is an output from a call to this API. */
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private DataFlow::Node getAnOutput() {
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exists(DataFlowDispatch::NonDelegateDataFlowCall call, DataFlowImplCommon::ReturnKindExt ret |
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result = ret.getAnOutNode(call)
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|
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this.getACall() = call.getDispatchCall()
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)
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}
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/** Holds if this API has a supported summary. */
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predicate hasSummary() {
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this instanceof SummarizedCallable or
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defaultAdditionalTaintStep(this.getAnInput(), _)
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}
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/** Holds if this API is is a constructor without parameters. */
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private predicate isParameterlessConstructor() {
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this instanceof Constructor and this.getNumberOfParameters() = 0
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}
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/** Holds if this API is part of a common testing library or framework. */
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private predicate isTestLibrary() { this.getDeclaringType() instanceof TestLibrary }
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/** Holds if this API is not worth supporting. */
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predicate isUninteresting() { this.isTestLibrary() or this.isParameterlessConstructor() }
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/** Holds if this API is a known source. */
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predicate isSource() {
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this.getAnOutput() instanceof RemoteFlowSource or sourceNode(this.getAnOutput(), _)
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}
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/** Holds if this API is a known sink. */
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predicate isSink() { sinkNode(this.getAnInput(), _) }
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/** Holds if this API is supported by existing CodeQL libraries, that is, it is either a recognized source or sink or has a flow summary. */
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predicate isSupported() { this.hasSummary() or this.isSource() or this.isSink() }
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}

‎csharp/ql/src/Telemetry/ExternalLibraryUsage.ql

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/**
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* @name External libraries
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* @description A list of external libraries used in the code
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* @kind metric
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* @tags summary
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* @id csharp/telemetry/external-libs
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*/
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import ExternalApi
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from int usages, string info
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where
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usages =
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strictcount(DispatchCall c, ExternalApi api |
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c = api.getACall() and
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api.getInfoPrefix() = info and
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not api.isUninteresting()
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)
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select info, usages order by usages desc

‎csharp/ql/src/Telemetry/SupportedExternalSinks.ql

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@@ -0,0 +1,18 @@
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/**
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* @name Supported sinks in external libraries
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* @description A list of 3rd party APIs detected as sinks. Excludes APIs exposed by test libraries.
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* @kind metric
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* @tags summary
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* @id csharp/telemetry/supported-external-api-sinks
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*/
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import ExternalApi
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from ExternalApi api, int usages
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where
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not api.isUninteresting() and
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api.isSink() and
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usages = strictcount(DispatchCall c | c = api.getACall())
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select api.getInfo() as info, usages order by usages desc

‎csharp/ql/src/Telemetry/SupportedExternalSources.ql

Lines changed: 18 additions & 0 deletions
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@@ -0,0 +1,18 @@
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/**
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* @name Supported sources in external libraries
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* @description A list of 3rd party APIs detected as sources. Excludes APIs exposed by test libraries.
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* @kind metric
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* @tags summary
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* @id csharp/telemetry/supported-external-api-sources
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*/
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import ExternalApi
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from ExternalApi api, int usages
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where
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not api.isUninteresting() and
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api.isSource() and
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usages = strictcount(DispatchCall c | c = api.getACall())
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select api.getInfo() as info, usages order by usages desc

‎csharp/ql/src/Telemetry/SupportedExternalTaint.ql

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/**
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* @name Supported flow steps in external libraries
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* @description A list of 3rd party APIs detected as flow steps. Excludes APIs exposed by test libraries.
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* @kind metric
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* @tags summary
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* @id csharp/telemetry/supported-external-api-taint
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*/
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import ExternalApi
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from ExternalApi api, int usages
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where
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not api.isUninteresting() and
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api.hasSummary() and
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usages = strictcount(DispatchCall c | c = api.getACall())
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select api.getInfo() as info, usages order by usages desc

‎csharp/ql/src/Telemetry/UnsupportedExternalAPIs.ql

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/**
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* @name Usage of unsupported APIs coming from external libraries
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* @description A list of 3rd party APIs used in the codebase. Excludes APIs exposed by test libraries.
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* @kind metric
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* @tags summary
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* @id csharp/telemetry/unsupported-external-api
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*/
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private import csharp
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private import semmle.code.csharp.dispatch.Dispatch
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private import ExternalApi
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from ExternalApi api, int usages
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where
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not api.isUninteresting() and
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not api.isSupported() and
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usages = strictcount(DispatchCall c | c = api.getACall())
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select api.getInfo() as info, usages order by usages desc

‎csharp/ql/test/query-tests/Telemetry/LibraryUsage/ExternalLibraryUsage.cs

Lines changed: 28 additions & 0 deletions
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using System;
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using System.Collections.Generic;
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public class LibraryUsage
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{
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public void M1()
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{
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var l = new List<object>(); // Uninteresting parameterless constructor
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var o = new object(); // Uninteresting parameterless constructor
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l.Add(o); // Has flow summary
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l.Add(o); // Has flow summary
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}
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public void M2()
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{
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var d0 = new DateTime(); // Uninteresting parameterless constructor
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var next0 = d0.AddYears(30); // Has no flow summary
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var d1 = new DateTime(2000, 1, 1); // Interesting constructor
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var next1 = next0.AddDays(3); // Has no flow summary
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var next2 = next1.AddYears(5); // Has no flow summary
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}
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public void M3()
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{
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var guid1 = Guid.Parse("{12345678-1234-1234-1234-123456789012}"); // Has no flow summary
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}
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}

‎csharp/ql/test/query-tests/Telemetry/LibraryUsage/ExternalLibraryUsage.expected

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| System.Private.CoreLib.dll#System | 5 |
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| System.Private.CoreLib.dll#System.Collections.Generic | 2 |

‎csharp/ql/test/query-tests/Telemetry/LibraryUsage/ExternalLibraryUsage.qlref

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Telemetry/ExternalLibraryUsage.ql

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