[DIFF-INFORMED] Actions: ArtifactPoisoning

Queries:
- https://github.com/d10c/codeql/blob/d10c/diff-informed-phase-3/actions/ql/src/Security/CWE-829/ArtifactPoisoningMedium.ql#L23
- https://github.com/d10c/codeql/blob/d10c/diff-informed-phase-3/actions/ql/src/Security/CWE-829/ArtifactPoisoningCritical.ql#L26

Author: d10c

actions/ql/lib/codeql/actions/security/ArtifactPoisoningQuery.qll

@@ -4,6 +4,7 @@ import codeql.actions.DataFlow
 import codeql.actions.dataflow.FlowSources
 import codeql.actions.security.PoisonableSteps
 import codeql.actions.security.UntrustedCheckoutQuery
+import codeql.actions.security.ControlChecks
 
 string unzipRegexp() { result = "(unzip|tar)\\s+.*" }
 
@@ -292,6 +293,16 @@ class ArtifactPoisoningSink extends DataFlow::Node {
   string getPath() { result = download.getPath() }
 }
 
+/**
+ * Gets the event that is relevant for the given node in the context of artifact poisoning.
+ *
+ * This is used to highlight the event in the query results when an alert is raised.
+ */
+Event getRelevantEventInPrivilegedContext(DataFlow::Node node) {
+  inPrivilegedContext(node.asExpr(), result) and
+  not exists(ControlCheck check | check.protects(node.asExpr(), result, "artifact-poisoning"))
+}
+
 /**
  * A taint-tracking configuration for unsafe artifacts
  * that is used may lead to artifact poisoning
@@ -318,6 +329,16 @@ private module ArtifactPoisoningConfig implements DataFlow::ConfigSig {
       exists(run.getScript().getAFileReadCommand())
     )
   }
+
+  predicate observeDiffInformedIncrementalMode() { any() }
+
+  Location getASelectedSourceLocation(DataFlow::Node source) { none() }
+
+  Location getASelectedSinkLocation(DataFlow::Node sink) {
+    result = sink.getLocation()
+    or
+    result = getRelevantEventInPrivilegedContext(sink).getLocation()
+  }
 }
 
 /** Tracks flow of unsafe artifacts that is used in an insecure way. */

actions/ql/src/Security/CWE-829/ArtifactPoisoningCritical.ql

@@ -19,10 +19,7 @@ import codeql.actions.security.ControlChecks
 from ArtifactPoisoningFlow::PathNode source, ArtifactPoisoningFlow::PathNode sink, Event event
 where
   ArtifactPoisoningFlow::flowPath(source, sink) and
-  inPrivilegedContext(sink.getNode().asExpr(), event) and
-  not exists(ControlCheck check |
-    check.protects(sink.getNode().asExpr(), event, "artifact-poisoning")
-  )
+  event = getRelevantEventInPrivilegedContext(sink.getNode())
 select sink.getNode(), source, sink,
   "Potential artifact poisoning in $@, which may be controlled by an external user ($@).", sink,
   sink.getNode().toString(), event, event.getName()