C#: Re-factor CommandInjection to use the new API.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/security/dataflow/CommandInjectionQuery.qll

@@ -23,6 +23,8 @@ abstract class Sink extends DataFlow::ExprNode { }
 abstract class Sanitizer extends DataFlow::ExprNode { }
 
 /**
+ * DEPRECATED: Use `CommandInjection` instead.
+ *
  * A taint-tracking configuration for command injection vulnerabilities.
  */
 class TaintTrackingConfiguration extends TaintTracking::Configuration {
@@ -35,6 +37,32 @@ class TaintTrackingConfiguration extends TaintTracking::Configuration {
   override predicate isSanitizer(DataFlow::Node node) { node instanceof Sanitizer }
 }
 
+/**
+ * A taint-tracking configuration for command injection vulnerabilities.
+ */
+module CommandInjectionConfig implements DataFlow::ConfigSig {
+  /**
+   * Holds if `source` is a relevant data flow source.
+   */
+  predicate isSource(DataFlow::Node source) { source instanceof Source }
+
+  /**
+   * Holds if `sink` is a relevant data flow sink.
+   */
+  predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
+
+  /**
+   * Holds if data flow through `node` is prohibited. This completely removes
+   * `node` from the data flow graph.
+   */
+  predicate isBarrier(DataFlow::Node node) { node instanceof Sanitizer }
+}
+
+/**
+ * A taint-tracking module for command injection vulnerabilities.
+ */
+module CommandInjection = TaintTracking::Global<CommandInjectionConfig>;
+
 /** A source of remote user input. */
 class RemoteSource extends Source instanceof RemoteFlowSource { }
 

csharp/ql/src/Security Features/CWE-078/CommandInjection.ql

@@ -15,9 +15,9 @@
 
 import csharp
 import semmle.code.csharp.security.dataflow.CommandInjectionQuery
-import semmle.code.csharp.dataflow.DataFlow::DataFlow::PathGraph
+import CommandInjection::PathGraph
 
-from TaintTrackingConfiguration c, DataFlow::PathNode source, DataFlow::PathNode sink
-where c.hasFlowPath(source, sink)
+from CommandInjection::PathNode source, CommandInjection::PathNode sink
+where CommandInjection::flowPath(source, sink)
 select sink.getNode(), source, sink, "This command line depends on a $@.", source.getNode(),
   "user-provided value"

csharp/ql/src/Security Features/CWE-078/StoredCommandInjection.ql

@@ -16,13 +16,19 @@
 import csharp
 import semmle.code.csharp.security.dataflow.flowsources.Stored
 import semmle.code.csharp.security.dataflow.CommandInjectionQuery
-import semmle.code.csharp.dataflow.DataFlow::DataFlow::PathGraph
+import StoredCommandInjection::PathGraph
 
-class StoredTaintTrackingConfiguration extends TaintTrackingConfiguration {
-  override predicate isSource(DataFlow::Node source) { source instanceof StoredFlowSource }
+module StoredCommandInjectionConfig implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node source) { source instanceof StoredFlowSource }
+
+  predicate isSink = CommandInjectionConfig::isSink/1;
+
+  predicate isBarrier = CommandInjectionConfig::isBarrier/1;
 }
 
-from StoredTaintTrackingConfiguration c, DataFlow::PathNode source, DataFlow::PathNode sink
-where c.hasFlowPath(source, sink)
+module StoredCommandInjection = TaintTracking::Global<StoredCommandInjectionConfig>;
+
+from StoredCommandInjection::PathNode source, StoredCommandInjection::PathNode sink
+where StoredCommandInjection::flowPath(source, sink)
 select sink.getNode(), source, sink, "This command line depends on a $@.", source.getNode(),
   "stored (potentially user-provided) value"