[DIFF-INFORMED] Actions: EnvVarInjection

https://github.com/d10c/codeql/blob/d10c/diff-informed-phase-3/actions/ql/src/Security/CWE-077/EnvVarInjectionMedium.ql#L35
https://github.com/d10c/codeql/blob/d10c/diff-informed-phase-3/actions/ql/src/Security/CWE-077/EnvVarInjectionCritical.ql#L46

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

@@ -126,6 +126,32 @@ class EnvVarInjectionFromMaDSink extends EnvVarInjectionSink {
   EnvVarInjectionFromMaDSink() { madSink(this, "envvar-injection") }
 }
 
+/**
+ * Get the relevant event for a sink in EnvVarInjectionCritical.ql where the source type is "artifact".
+ */
+Event getRelevantArtifactEventInPrivilegedContext(DataFlow::Node sink) {
+  inPrivilegedContext(sink.asExpr(), result) and
+  not exists(ControlCheck check |
+    check
+        .protects(sink.asExpr(), result,
+          ["envvar-injection", "untrusted-checkout", "artifact-poisoning"])
+  ) and
+  (
+    sink instanceof EnvVarInjectionFromFileReadSink or
+    madSink(sink, "envvar-injection")
+  )
+}
+
+/**
+ * Get the relevant event for a sink in EnvVarInjectionCritical.ql where the source type is not "artifact".
+ */
+Event getRelevantNonArtifactEventInPrivilegedContext(DataFlow::Node sink) {
+  inPrivilegedContext(sink.asExpr(), result) and
+  not exists(ControlCheck check |
+    check.protects(sink.asExpr(), result, ["envvar-injection", "code-injection"])
+  )
+}
+
 /**
  * A taint-tracking configuration for unsafe user input
  * that is used to construct and evaluate an environment variable.
@@ -163,6 +189,18 @@ private module EnvVarInjectionConfig 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 = getRelevantArtifactEventInPrivilegedContext(sink).getLocation()
+    or
+    result = getRelevantNonArtifactEventInPrivilegedContext(sink).getLocation()
+  }
 }
 
 /** Tracks flow of unsafe user input that is used to construct and evaluate an environment variable. */

actions/ql/src/Security/CWE-077/EnvVarInjectionCritical.ql

@@ -22,26 +22,15 @@ import codeql.actions.security.ControlChecks
 from EnvVarInjectionFlow::PathNode source, EnvVarInjectionFlow::PathNode sink, Event event
 where
   EnvVarInjectionFlow::flowPath(source, sink) and
-  inPrivilegedContext(sink.getNode().asExpr(), event) and
   // exclude paths to file read sinks from non-artifact sources
   (
     // source is text
     not source.getNode().(RemoteFlowSource).getSourceType() = "artifact" and
-    not exists(ControlCheck check |
+    event = getRelevantNonArtifactEventInPrivilegedContext(sink.getNode())
-      check.protects(sink.getNode().asExpr(), event, ["envvar-injection", "code-injection"])
-    )
     or
     // source is an artifact or a file from an untrusted checkout
     source.getNode().(RemoteFlowSource).getSourceType() = "artifact" and
-    not exists(ControlCheck check |
+    event = getRelevantArtifactEventInPrivilegedContext(sink.getNode())
-      check
-          .protects(sink.getNode().asExpr(), event,
-            ["envvar-injection", "untrusted-checkout", "artifact-poisoning"])
-    ) and
-    (
-      sink.getNode() instanceof EnvVarInjectionFromFileReadSink or
-      madSink(sink.getNode(), "envvar-injection")
-    )
   )
 select sink.getNode(), source, sink,
   "Potential environment variable injection in $@, which may be controlled by an external user ($@).",