Impose a local limit on path lengths (RIPD-350)

src/ripple/module/app/transactors/Payment.cpp

@@ -240,9 +240,14 @@ TER Payment::doApply ()
         try
         {
             bool const openLedger = (mParams & tapOPEN_LEDGER);
-            bool const tooManyPaths = spsPaths.size () > MaxPathSize;
 
-            terResult = openLedger && tooManyPaths
+            bool pathTooBig = spsPaths.size () > MaxPathSize;
+
+            for (auto const& path : spsPaths)
+                if (path.size () > MaxPathLength)
+                    pathTooBig = true;
+
+            terResult = openLedger && pathTooBig
                         ? telBAD_PATH_COUNT // Too many paths for proposed ledger.
                         : path::rippleCalculate (
                               mEngine->view (),

src/ripple/module/app/transactors/Payment.h

@@ -28,6 +28,9 @@ class Payment
     /* The largest number of paths we allow */
     static std::size_t const MaxPathSize = 6;
 
+    /* The longest path we allow */
+    static std::size_t const MaxPathLength = 8;
+
 public:
     Payment (
         SerializedTransaction const& txn,