Limit recursion level in XmlDecoder.ReadMatrix() and XmlEncoder.Write…

…Matrix() (#1295)
OPCFoundation · Feb 25, 2021 · c541994 · c541994
1 parent c382922
commit c541994
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Showing 2 changed files with 26 additions and 0 deletions.
diff --git a/Stack/Opc.Ua.Core/Types/Encoders/XmlDecoder.cs b/Stack/Opc.Ua.Core/Types/Encoders/XmlDecoder.cs
@@ -2625,6 +2625,17 @@ public Array ReadEnumeratedArray(string fieldName, System.Type enumType)
         /// </summary>
         private Matrix ReadMatrix(string fieldName)
         {
+            // check the nesting level for avoiding a stack overflow.
+            if (m_nestingLevel > m_context.MaxEncodingNestingLevels)
+            {
+                throw ServiceResultException.Create(
+                    StatusCodes.BadEncodingLimitsExceeded,
+                    "Maximum nesting level of {0} was exceeded",
+                    m_context.MaxEncodingNestingLevels);
+            }
+
+            m_nestingLevel++;
+
             Array elements = null;
             Int32Collection dimensions = null;
             TypeInfo typeInfo = null;
@@ -2647,6 +2658,8 @@ private Matrix ReadMatrix(string fieldName)
                 EndField(fieldName);
             }
 
+            m_nestingLevel--;
+
             if (elements == null)
             {
                 throw new ServiceResultException(StatusCodes.BadDecodingError, "The Matrix contains invalid elements");

diff --git a/Stack/Opc.Ua.Core/Types/Encoders/XmlEncoder.cs b/Stack/Opc.Ua.Core/Types/Encoders/XmlEncoder.cs
@@ -1950,6 +1950,17 @@ public void WriteExtensionObjectBody(object body)
         /// </summary>
         private void WriteMatrix(string fieldName, Matrix value)
         {
+            // check the nesting level for avoiding a stack overflow.
+            if (m_nestingLevel > m_context.MaxEncodingNestingLevels)
+            {
+                throw ServiceResultException.Create(
+                    StatusCodes.BadEncodingLimitsExceeded,
+                    "Maximum nesting level of {0} was exceeded",
+                    m_context.MaxEncodingNestingLevels);
+            }
+
+            m_nestingLevel++;
+
             if (BeginField(fieldName, value == null, true, true))
             {
                 PushNamespace(Namespaces.OpcUaXsd);
@@ -1967,6 +1978,8 @@ private void WriteMatrix(string fieldName, Matrix value)
 
                 EndField(fieldName);
             }
+
+            m_nestingLevel--;
         }
 
         /// <summary>