police nesting depth in java props parser (#397)

properties/src/main/java/com/fasterxml/jackson/dataformat/javaprop/JavaPropsParser.java

@@ -266,6 +266,7 @@ public JsonToken nextToken() throws IOException {
             if (_readContext == null) { // end of content
                 return null;
             }
+            _streamReadConstraints.validateNestingDepth(_readContext.getNestingDepth());
         }
         return _currToken;
     }

properties/src/main/java/com/fasterxml/jackson/dataformat/javaprop/io/JPropReadContext.java

@@ -52,6 +52,7 @@ public JPropReadContext(int contextType, JPropReadContext p, JPropNode node)
         _index = -1;
         _parent = p;
         _branchText = node.getValue();
+        _nestingDepth = p == null ? 0 : p._nestingDepth + 1;
     }
 
     public static JPropReadContext create(JPropNode root) {

properties/src/test/java/com/fasterxml/jackson/dataformat/javaprop/dos/DeepNestParserTest.java

@@ -0,0 +1,54 @@
+package com.fasterxml.jackson.dataformat.javaprop.dos;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
+import com.fasterxml.jackson.core.StreamReadConstraints;
+import com.fasterxml.jackson.core.exc.StreamConstraintsException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.javaprop.JavaPropsFactory;
+import com.fasterxml.jackson.dataformat.javaprop.ModuleTestBase;
+
+import java.io.IOException;
+
+public class DeepNestParserTest extends ModuleTestBase {
+
+    public void testDeeplyNestedData() throws IOException {
+        final int depth = 1500;
+        final String doc = genDeeplyNestedData(depth);
+        final ObjectMapper mapper = newPropertiesMapper();
+        try (JsonParser jp = mapper.createParser(doc)) {
+            JsonToken jt;
+            while ((jt = jp.nextToken()) != null) {
+
+            }
+            fail("expected StreamConstraintsException");
+        } catch (StreamConstraintsException e) {
+            assertEquals("Depth (1001) exceeds the maximum allowed nesting depth (1000)", e.getMessage());
+        }
+    }
+
+    public void testDeeplyNestedDataWithUnconstrainedMapper() throws IOException {
+        final int depth = 1500;
+        final String doc = genDeeplyNestedData(depth);
+        final JavaPropsFactory factory = JavaPropsFactory.builder()
+                .streamReadConstraints(StreamReadConstraints.builder().maxNestingDepth(Integer.MAX_VALUE).build())
+                .build();
+        final ObjectMapper mapper = propertiesMapperBuilder(factory).build();
+        try (JsonParser jp = mapper.createParser(doc)) {
+            JsonToken jt;
+            while ((jt = jp.nextToken()) != null) {
+
+            }
+        }
+    }
+
+    private String genDeeplyNestedData(final int depth) {
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < depth; i++) {
+            if (i > 1) sb.append('.');
+            sb.append('a');
+        }
+        sb.append("=val");
+        return sb.toString();
+    }
+}