python: add machinery for MaD barriers

and reinstate previously removed barrier
now as a MaD row

Author: yoff

javascript/ql/lib/semmle/javascript/dataflow/internal/BarrierGuards.qll

@@ -36,6 +36,36 @@ module MakeBarrierGuard<BarrierGuardSig BaseGuard> {
   }
 }
 
+/**
+ * Provides access to barrier guards defined via models-as-data.
+ */
+module ExternalBarrierGuard {
+  private predicate guardCheck(DataFlow::Node g, Expr e, boolean branch, string kind) {
+    exists(API::CallNode call, API::Node parameter |
+      parameter = call.getAParameter() and
+      parameter = ModelOutput::getABarrierGuardNode(kind, branch)
+    |
+      g = call and
+      e = parameter.asSink().asExpr()
+    )
+  }
+
+  private class BarrierGuard extends DataFlow::Node {
+    BarrierGuard() { guardCheck(this, _, _, _) }
+
+    predicate blocksExpr(boolean outcome, Expr e, string kind) {
+      guardCheck(this, e, outcome, kind)
+    }
+  }
+
+  /**
+   * Gets a barrier guard node of the given `kind` defined via models-as-data.
+   */
+  DataFlow::Node getAnExternalBarrierNode(string kind) {
+    result = MakeStateBarrierGuard<string, BarrierGuard>::getABarrierNode(kind)
+  }
+}
+
 deprecated private module DeprecationWrapper {
   signature class LabeledBarrierGuardSig extends DataFlow::Node {
     /**

javascript/ql/lib/semmle/javascript/frameworks/Credentials.qll

@@ -29,7 +29,7 @@ module CredentialsExpr {
 private class CredentialsFromModel extends CredentialsNode {
   string kind;
 
-  CredentialsFromModel() { this = ModelOutput::getASinkNode("credentials-" + kind).asSink() }
+  CredentialsFromModel() { ModelOutput::sinkNode(this, "credentials-" + kind) }
 
   override string getCredentialsKind() { result = CredentialsExpr::normalizeKind(kind) }
 }

javascript/ql/lib/semmle/javascript/frameworks/NoSQL.qll

@@ -13,7 +13,7 @@ module NoSql {
   }
 
   private class QueryFromModel extends Query {
-    QueryFromModel() { this = ModelOutput::getASinkNode("nosql-injection").asSink() }
+    QueryFromModel() { ModelOutput::sinkNode(this, "nosql-injection") }
   }
 }
 
@@ -46,7 +46,7 @@ private module MongoDB {
 
     override DataFlow::Node getAQueryArgument() {
       result = [this.getAnArgument(), this.getOptionArgument(_, _)] and
-      result = ModelOutput::getASinkNode("mongodb.sink").asSink()
+      ModelOutput::sinkNode(result, "mongodb.sink")
     }
 
     override DataFlow::Node getAResult() {

javascript/ql/lib/semmle/javascript/frameworks/SQL.qll

@@ -9,7 +9,7 @@ module SQL {
   abstract class SqlString extends DataFlow::Node { }
 
   private class SqlStringFromModel extends SqlString {
-    SqlStringFromModel() { this = ModelOutput::getASinkNode("sql-injection").asSink() }
+    SqlStringFromModel() { ModelOutput::sinkNode(this, "sql-injection") }
   }
 
   /**

javascript/ql/lib/semmle/javascript/frameworks/data/ModelsAsData.qll

@@ -30,7 +30,7 @@ import Shared::ModelOutput as ModelOutput
  * A remote flow source originating from a MaD source row.
  */
 private class RemoteFlowSourceFromMaD extends RemoteFlowSource {
-  RemoteFlowSourceFromMaD() { this = ModelOutput::getASourceNode("remote").asSource() }
+  RemoteFlowSourceFromMaD() { ModelOutput::sourceNode(this, "remote") }
 
   override string getSourceType() { result = "Remote flow" }
 }
@@ -39,9 +39,9 @@ private class RemoteFlowSourceFromMaD extends RemoteFlowSource {
  * A threat-model flow source originating from a data extension.
  */
 private class ThreatModelSourceFromDataExtension extends ThreatModelSource::Range {
-  ThreatModelSourceFromDataExtension() { this = ModelOutput::getASourceNode(_).asSource() }
+  ThreatModelSourceFromDataExtension() { ModelOutput::sourceNode(this, _) }
 
-  override string getThreatModel() { this = ModelOutput::getASourceNode(result).asSource() }
+  override string getThreatModel() { ModelOutput::sourceNode(this, result) }
 
   override string getSourceType() {
     result = "Source node (" + this.getThreatModel() + ") [from data-extension]"

javascript/ql/lib/semmle/javascript/frameworks/data/internal/ApiGraphModels.qll

@@ -344,6 +344,26 @@ private predicate sinkModel(string type, string path, string kind, string model)
   )
 }
 
+/** Holds if a barrier model exists for the given parameters. */
+private predicate barrierModel(string type, string path, string kind, string model) {
+  // No deprecation adapter for barrier models, they were not around back then.
+  exists(QlBuiltins::ExtensionId madId |
+    Extensions::barrierModel(type, path, kind, madId) and
+    model = "MaD:" + madId.toString()
+  )
+}
+
+/** Holds if a barrier guard model exists for the given parameters. */
+private predicate barrierGuardModel(
+  string type, string path, string branch, string kind, string model
+) {
+  // No deprecation adapter for barrier models, they were not around back then.
+  exists(QlBuiltins::ExtensionId madId |
+    Extensions::barrierGuardModel(type, path, branch, kind, madId) and
+    model = "MaD:" + madId.toString()
+  )
+}
+
 /** Holds if a summary model `row` exists for the given parameters. */
 private predicate summaryModel(
   string type, string path, string input, string output, string kind, string model
@@ -400,6 +420,8 @@ predicate isRelevantType(string type) {
   (
     sourceModel(type, _, _, _) or
     sinkModel(type, _, _, _) or
+    barrierModel(type, _, _, _) or
+    barrierGuardModel(type, _, _, _, _) or
     summaryModel(type, _, _, _, _, _) or
     typeModel(_, type, _)
   ) and
@@ -427,6 +449,8 @@ predicate isRelevantFullPath(string type, string path) {
   (
     sourceModel(type, path, _, _) or
     sinkModel(type, path, _, _) or
+    barrierModel(type, path, _, _) or
+    barrierGuardModel(type, path, _, _, _) or
     summaryModel(type, path, _, _, _, _) or
     typeModel(_, type, path)
   )
@@ -745,6 +769,32 @@ module ModelOutput {
       )
     }
 
+    /**
+     * Holds if a barrier model contributed `barrier` with the given `kind`.
+     */
+    cached
+    API::Node getABarrierNode(string kind, string model) {
+      exists(string type, string path |
+        barrierModel(type, path, kind, model) and
+        result = getNodeFromPath(type, path)
+      )
+    }
+
+    /**
+     * Holds if a barrier model contributed `barrier` with the given `kind` for the given `branch`.
+     */
+    cached
+    API::Node getABarrierGuardNode(string kind, boolean branch, string model) {
+      exists(string type, string path, string branch_str |
+        branch = true and branch_str = "true"
+        or
+        branch = false and branch_str = "false"
+      |
+        barrierGuardModel(type, path, branch_str, kind, model) and
+        result = getNodeFromPath(type, path)
+      )
+    }
+
     /**
      * Holds if a relevant summary exists for these parameters.
      */
@@ -787,15 +837,46 @@ module ModelOutput {
   private import codeql.mad.ModelValidation as SharedModelVal
 
   /**
-   * Holds if a CSV source model contributed `source` with the given `kind`.
+   * Holds if an external model contributed `source` with the given `kind`.
    */
   API::Node getASourceNode(string kind) { result = getASourceNode(kind, _) }
 
   /**
-   * Holds if a CSV sink model contributed `sink` with the given `kind`.
+   * Holds if an external model contributed `sink` with the given `kind`.
    */
   API::Node getASinkNode(string kind) { result = getASinkNode(kind, _) }
 
+  /**
+   * Holds if an external model contributed `barrier` with the given `kind`.
+   */
+  API::Node getABarrierNode(string kind) { result = getABarrierNode(kind, _) }
+
+  /**
+   * Holds if an external model contributed `barrier-guard` with the given `kind` and `branch`.
+   */
+  API::Node getABarrierGuardNode(string kind, boolean branch) {
+    result = getABarrierGuardNode(kind, branch, _)
+  }
+
+  /**
+   * Holds if `node` is specified as a source with the given kind in an external model.
+   */
+  predicate sourceNode(DataFlow::Node node, string kind) { node = getASourceNode(kind).asSource() }
+
+  /**
+   * Holds if `node` is specified as a sink with the given kind in an external model.
+   */
+  predicate sinkNode(DataFlow::Node node, string kind) { node = getASinkNode(kind).asSink() }
+
+  /**
+   * Holds if `node` is specified as a barrier with the given kind in an external model.
+   */
+  predicate barrierNode(DataFlow::Node node, string kind) {
+    node = getABarrierNode(kind).asSource()
+    or
+    node = DataFlow::ExternalBarrierGuard::getAnExternalBarrierNode(kind)
+  }
+
   private module KindValConfig implements SharedModelVal::KindValidationConfigSig {
     predicate summaryKind(string kind) { summaryModel(_, _, _, _, kind, _) }
 

javascript/ql/lib/semmle/javascript/frameworks/data/internal/ApiGraphModelsExtensions.qll

@@ -20,6 +20,26 @@ extensible predicate sourceModel(
  */
 extensible predicate sinkModel(string type, string path, string kind, QlBuiltins::ExtensionId madId);
 
+/**
+ * Holds if the value at `(type, path)` should be seen as a barrier
+ * of the given `kind` and `madId` is the data extension row number.
+ */
+extensible predicate barrierModel(
+  string type, string path, string kind, QlBuiltins::ExtensionId madId
+);
+
+/**
+ * Holds if the value at `(type, path)` should be seen as a barrier guard
+ * of the given `kind` and `madId` is the data extension row number.
+ * `path` is assumed to lead to a parameter of a call (possibly `self`), and
+ * the call is guarding the parameter.
+ * `branch` is either `true` or `false`, indicating which branch of the guard
+ * is protecting the parameter.
+ */
+extensible predicate barrierGuardModel(
+  string type, string path, string branch, string kind, QlBuiltins::ExtensionId madId
+);
+
 /**
  * Holds if in calls to `(type, path)`, the value referred to by `input`
  * can flow to the value referred to by `output` and `madId` is the data

javascript/ql/lib/semmle/javascript/frameworks/data/internal/empty.model.yml

@@ -16,6 +16,16 @@ extensions:
       extensible: summaryModel
     data: []
 
+  - addsTo:
+      pack: codeql/javascript-all
+      extensible: barrierModel
+    data: []
+
+  - addsTo:
+      pack: codeql/javascript-all
+      extensible: barrierGuardModel
+    data: []
+
   - addsTo:
       pack: codeql/javascript-all
       extensible: neutralModel

javascript/ql/lib/semmle/javascript/security/CorsPermissiveConfigurationCustomizations.qll

@@ -66,7 +66,7 @@ module CorsPermissiveConfiguration {
    * The value of cors origin when initializing the application.
    */
   class CorsOriginSink extends Sink, DataFlow::ValueNode {
-    CorsOriginSink() { this = ModelOutput::getASinkNode("cors-origin").asSink() }
+    CorsOriginSink() { ModelOutput::sinkNode(this, "cors-origin") }
   }
 
   /**

javascript/ql/lib/semmle/javascript/security/dataflow/ClientSideUrlRedirectCustomizations.qll

@@ -268,6 +268,6 @@ module ClientSideUrlRedirect {
   }
 
   private class SinkFromModel extends Sink {
-    SinkFromModel() { this = ModelOutput::getASinkNode("url-redirection").asSink() }
+    SinkFromModel() { ModelOutput::sinkNode(this, "url-redirection") }
   }
 }