Rust: Source and sink doc / tidy up

rust/ql/lib/codeql/rust/Concepts.qll

@@ -152,6 +152,29 @@ class ModeledRemoteSource extends RemoteSource::Range {
   ModeledRemoteSource() { sourceNode(this, "remote") }
 }
 
+/**
+ * A data flow sink that is used in a query.
+ *
+ * Extend this class to refine existing API models. If you want to model new APIs,
+ * extend `QuerySink::Range` instead.
+ */
+final class QuerySink = QuerySink::Range;
+
+/**
+ * Provides a class for modeling new query sinks.
+ */
+module QuerySink {
+  /**
+   * A data flow sink that is used in a query.
+   */
+  abstract class Range extends DataFlow::Node {
+    /**
+     * Gets a string that describes the type of this sink (usually the query it applies to).
+     */
+    abstract string getSinkType();
+  }
+}
+
 /**
  * A data flow node that constructs a SQL statement (for later execution).
  *

rust/ql/lib/codeql/rust/dataflow/FlowSink.qll

@@ -1,4 +1,20 @@
-/** Provides classes and predicates for defining flow sinks. */
+/**
+ * Provides classes and predicates for defining flow sinks.
+ *
+ * Flow sinks defined here feed into data flow configurations as follows:
+ *
+ *   data from `*.model.yml` | QL extensions of `FlowSink::Range`
+ *    v                         v
+ *   `FlowSink` (associated with a models-as-data `kind` string)
+ *    v
+ *   `sinkNode` predicate | other QL defined sinks, for example using concepts
+ *    v                      v
+ *   various `Sink` classes for specific data flow configurations <- extending `QuerySink`
+ *
+ * New sinks should be defined using models-as-data, QL extensions of
+ * `FlowSink::Range`, or concepts. Data flow configurations should use the
+ * `sinkNode` predicate and/or concepts to define their sinks.
+ */
 
 private import rust
 private import internal.FlowSummaryImpl as Impl
@@ -12,7 +28,7 @@ private module Sinks {
 
 /** Provides the `Range` class used to define the extent of `FlowSink`. */
 module FlowSink {
-  /** A flow source. */
+  /** A flow sink. */
   abstract class Range extends Impl::Public::SinkElement {
     bindingset[this]
     Range() { any() }

rust/ql/lib/codeql/rust/dataflow/FlowSource.qll

@@ -1,4 +1,26 @@
-/** Provides classes and predicates for defining flow sources. */
+/**
+ * Provides classes and predicates for defining flow sources.
+ *
+ * Flow sources defined here feed into the `ActiveThreatModelSource` class and
+ * ultimately reach data flow configurations as follows:
+ *
+ *   data from `*.model.yml` | QL extensions of `FlowSource::Range`
+ *    v                         v
+ *   `FlowSource` (associated with a models-as-data `kind` string)
+ *    v
+ *   `sourceNode` predicate | (theoretically other QL defined sources)
+ *    v                        v
+ *   `ThreatModelSource` (associated with a threat model source type)
+ *    v
+ *   `ActiveThreatModelSource` (just the enabled sources)
+ *    v
+ *   various `Source` classes for specific data flow configurations
+ *
+ * New sources should be defined using models-as-data or QL extensions of
+ * `FlowSource::Range`. Data flow configurations on the other hand should use
+ * `ActiveThreatModelSource` to match sources enabled in the user
+ * configuration.
+ */
 
 private import rust
 private import internal.FlowSummaryImpl as Impl

rust/ql/lib/codeql/rust/security/CleartextLoggingExtensions.qll

@@ -7,6 +7,7 @@ import rust
 private import codeql.rust.dataflow.DataFlow
 private import codeql.rust.dataflow.internal.DataFlowImpl
 private import codeql.rust.security.SensitiveData
+private import codeql.rust.Concepts
 
 /**
  * Provides default sources, sinks and barriers for detecting cleartext logging
@@ -21,7 +22,9 @@ module CleartextLogging {
   /**
    * A data flow sink for cleartext logging vulnerabilities.
    */
-  abstract class Sink extends DataFlow::Node { }
+  abstract class Sink extends QuerySink::Range {
+    override string getSinkType() { result = "CleartextLogging" }
+  }
 
   /**
    * A barrier for cleartext logging vulnerabilities.

rust/ql/lib/codeql/rust/security/SqlInjectionExtensions.qll

@@ -23,7 +23,9 @@ module SqlInjection {
   /**
    * A data flow sink for SQL injection vulnerabilities.
    */
-  abstract class Sink extends DataFlow::Node { }
+  abstract class Sink extends QuerySink::Range {
+    override string getSinkType() { result = "SqlInjection" }
+  }
 
   /**
    * A barrier for SQL injection vulnerabilities.

rust/ql/lib/codeql/rust/security/WeakSensitiveDataHashingExtensions.qll

@@ -43,7 +43,7 @@ module NormalHashFunction {
    * data" vulnerabilities that applies to data that does not require computationally expensive
    * hashing. That is, a broken or weak hashing algorithm.
    */
-  abstract class Sink extends DataFlow::Node {
+  abstract class Sink extends QuerySink::Range {
     /**
      * Gets the name of the weak hashing algorithm.
      */
@@ -76,6 +76,8 @@ module NormalHashFunction {
   class WeakHashingOperationInputAsSink extends Sink {
     Cryptography::HashingAlgorithm algorithm;
 
+    override string getSinkType() { result = "WeakSensitiveDataHashing" }
+
     WeakHashingOperationInputAsSink() {
       exists(Cryptography::CryptographicOperation operation |
         algorithm.isWeak() and
@@ -114,7 +116,9 @@ module ComputationallyExpensiveHashFunction {
    * hashing. That is, a broken or weak hashing algorithm or one that is not computationally
    * expensive enough for password hashing.
    */
-  abstract class Sink extends DataFlow::Node {
+  abstract class Sink extends QuerySink::Range {
+    override string getSinkType() { result = "WeakSensitiveDataHashing" }
+
     /**
      * Gets the name of the weak hashing algorithm.
      */

rust/ql/src/queries/summary/QuerySinkCounts.ql

@@ -10,8 +10,9 @@
 
 import rust
 import codeql.rust.dataflow.DataFlow
+import codeql.rust.Concepts
 import Stats
 
 from string kind, int num
-where num = strictcount(DataFlow::Node n | getAQuerySinkKind(n) = kind)
+where num = strictcount(QuerySink s | s.getSinkType() = kind)
 select kind, num

rust/ql/src/queries/summary/QuerySinks.ql

@@ -11,7 +11,8 @@
 
 import rust
 import codeql.rust.dataflow.DataFlow
+import codeql.rust.Concepts
 import Stats
 
-from DataFlow::Node n
-select n, "Sink for " + strictconcat(getAQuerySinkKind(n), ", ") + "."
+from QuerySink s
+select s, "Sink for " + concat(s.getSinkType(), ", ") + "."

rust/ql/src/queries/summary/Stats.qll

@@ -9,8 +9,11 @@ private import codeql.rust.dataflow.internal.TaintTrackingImpl
 private import codeql.rust.internal.AstConsistency as AstConsistency
 private import codeql.rust.controlflow.internal.CfgConsistency as CfgConsistency
 private import codeql.rust.dataflow.internal.DataFlowConsistency as DataFlowConsistency
-private import codeql.rust.security.SqlInjectionExtensions
+private import codeql.rust.Concepts
+// import all query extensions files, so that all extensions of `QuerySink` are found
 private import codeql.rust.security.CleartextLoggingExtensions
+private import codeql.rust.security.SqlInjectionExtensions
+private import codeql.rust.security.WeakSensitiveDataHashingExtensions
 
 /**
  * Gets a count of the total number of lines of code in the database.
@@ -55,16 +58,7 @@ int getTaintEdgesCount() {
     )
 }
 
-/**
- * Gets a kind of query for which `n` is a sink (if any).
- */
-string getAQuerySinkKind(DataFlow::Node n) {
-  n instanceof SqlInjection::Sink and result = "SqlInjection"
-  or
-  n instanceof CleartextLogging::Sink and result = "CleartextLogging"
-}
-
 /**
  * Gets a count of the total number of query sinks in the database.
  */
-int getQuerySinksCount() { result = count(DataFlow::Node n | exists(getAQuerySinkKind(n))) }
+int getQuerySinksCount() { result = count(QuerySink s) }