C++: Prepare 'CleartextSqliteDatabase.ql' for use-use flow.

MathiasVP · MathiasVP · commit 1d80e94bb4ec · 2022-12-16T17:10:10.000Z
diff --git a/cpp/ql/src/Security/CWE/CWE-313/CleartextSqliteDatabase.ql b/cpp/ql/src/Security/CWE/CWE-313/CleartextSqliteDatabase.ql
@@ -36,16 +36,29 @@ Field getRecField(Class c) {
   result = getRecField(c.getAField().getUnspecifiedType().stripType())
 }
 
+/**
+ * Holds if `source` is a use of a sensitive expression `sensitive`, or
+ * if `source` is the output argument (with a sensitive name) of a function.
+ */
+predicate isSourceImpl(DataFlow::Node source, SensitiveExpr sensitive) {
+  [source.asExpr(), source.asDefiningArgument()] = sensitive
+}
+
+/** Holds if `sink` is an argument to an Sqlite function call `c`. */
+predicate isSinkImpl(DataFlow::Node sink, SqliteFunctionCall c) {
+  [sink.asExpr(), sink.asIndirectExpr()] = c.getASource()
+}
+
 /**
  * A taint flow configuration for flow from a sensitive expression to a `SqliteFunctionCall` sink.
  */
 class FromSensitiveConfiguration extends TaintTracking::Configuration {
   FromSensitiveConfiguration() { this = "FromSensitiveConfiguration" }
 
-  override predicate isSource(DataFlow::Node source) { source.asExpr() instanceof SensitiveExpr }
+  override predicate isSource(DataFlow::Node source) { isSourceImpl(source, _) }
 
   override predicate isSink(DataFlow::Node sink) {
-    any(SqliteFunctionCall c).getASource() = sink.asExpr() and
+    isSinkImpl(sink, _) and
     not sqlite_encryption_used()
   }
 
@@ -58,7 +71,7 @@ class FromSensitiveConfiguration extends TaintTracking::Configuration {
     this.isSink(node) and
     // constrain `content` to a field inside the node.
     exists(Class c |
-      node.asExpr().getUnspecifiedType().stripType() = c and
+      node.getType().getUnspecifiedType().stripType() = c and
       content.(DataFlow::FieldContent).getField() = getRecField(c)
     )
     or
@@ -72,8 +85,8 @@ from
   DataFlow::PathNode sink, SqliteFunctionCall sqliteCall
 where
   config.hasFlowPath(source, sink) and
-  source.getNode().asExpr() = sensitive and
-  sqliteCall.getASource() = sink.getNode().asExpr()
+  isSourceImpl(source.getNode(), sensitive) and
+  isSinkImpl(sink.getNode(), sqliteCall)
 select sqliteCall, source, sink,
   "This SQLite call may store $@ in a non-encrypted SQLite database.", sensitive,
   "sensitive information"
