Adds MySQL/example.ql

  MindShaRE blog on MySQL Cluster Taint Analysis
  https://www.zerodayinitiative.com/blog

MySQL/example.ql

@@ -0,0 +1,76 @@
+/**
+ * @id cpp/example/empty-block
+ * @kind path-problem
+ */
+
+import cpp
+import DataFlow::PathGraph
+import semmle.code.cpp.dataflow.TaintTracking
+import semmle.code.cpp.controlflow.Guards
+import semmle.code.cpp.valuenumbering.GlobalValueNumbering
+
+class SystemCfg extends TaintTracking::Configuration {
+  SystemCfg() { this = "SystemCfg" }
+
+  override predicate isSource(DataFlow::Node node) {
+    exists (FieldAccess va |
+      node.asExpr() = va
+      and
+      va.getTarget().getName().matches("theData")
+    )
+    or
+    exists(FunctionCall fc |
+      fc.getTarget().hasName("getSection") and
+      fc.getArgument(0) = node.asDefiningArgument()
+    )
+
+  }
+
+  // https://msrc-blog.microsoft.com/2019/03/19/vulnerability-hunting-with-semmle-ql-part-2/
+  override predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) {
+    exists(Expr e, FieldAccess fa |
+      node1.asExpr() = e and node2.asExpr() = fa |
+      fa.getQualifier*() = e and not (fa.getParent() instanceof FieldAccess)
+    )
+  }
+
+  override predicate isSink(DataFlow::Node node) {
+    exists (ArrayExpr ae | 
+      node.asExpr() = ae.getArrayOffset()
+    )
+    or
+    exists(FunctionCall call |
+      (
+        call.getTarget().getName() = "memcpy"
+        or
+        call.getTarget().getName() = "memset"
+        or
+        call.getTarget().getName() = "memmove"
+      )
+      and
+      node.asExpr() = call.getArgument(2)
+    )
+  }
+
+  override predicate isSanitizer(DataFlow::Node node) {
+    exists(MacroInvocation mi |
+      mi.getMacroName().matches("%ptrCheckGuard%")
+      and mi.getExpr() = node.asExpr()
+    )
+    or
+    exists( IfStmt aif, RelationalOperation rop |
+      node.asExpr().(VariableAccess).getTarget().getAnAccess() = aif.getControllingExpr().getAChild*()
+      and aif.getASuccessor+() = node.asExpr()
+      and not ( node.asExpr() = aif.getControllingExpr().getAChild*() )
+      and rop = aif.getControllingExpr().getAChild*() 
+    )
+  }
+
+}
+
+from DataFlow::PathNode sink, DataFlow::PathNode source, SystemCfg cfg
+where
+  cfg.hasFlowPath(source, sink)
+select sink.getNode(), source, sink, sink.getNode().getLocation().toString()
+
+