Add boundary check for PtNode reading position.

Bug: 10743878
Change-Id: I6727b12b0ef98bb9cfb3ca95aeab2c79749f47a2
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
index 56ef60a..6666e1f 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.cpp
@@ -25,6 +25,13 @@
 
 void DynamicPatriciaTrieNodeReader::fetchNodeInfoFromBufferAndProcessMovedNode(const int nodePos,
         const int maxCodePointCount, int *const outCodePoints) {
+    if (nodePos < 0 || nodePos >= mBuffer->getTailPosition()) {
+        AKLOGE("Fetching PtNode info form invalid dictionary position: %d, dictionary size: %d",
+                nodePos, mBuffer->getTailPosition());
+        ASSERT(false);
+        invalidatePtNodeInfo();
+        return;
+    }
     const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(nodePos);
     const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
     int pos = nodePos;
@@ -94,4 +101,19 @@
     }
 }
 
+void DynamicPatriciaTrieNodeReader::invalidatePtNodeInfo() {
+    mHeadPos = NOT_A_VALID_WORD_POS;
+    mFlags = 0;
+    mParentPos = NOT_A_DICT_POS;
+    mCodePointCount = 0;
+    mProbabilityFieldPos = NOT_A_DICT_POS;
+    mProbability = NOT_A_PROBABILITY;
+    mChildrenPosFieldPos = NOT_A_DICT_POS;
+    mChildrenPos = NOT_A_DICT_POS;
+    mBigramLinkedNodePos = NOT_A_DICT_POS;
+    mShortcutPos = NOT_A_DICT_POS;
+    mBigramPos = NOT_A_DICT_POS;
+    mSiblingPos = NOT_A_VALID_WORD_POS;
+}
+
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
index 89d38a5..6fd52b9 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/dynamic_patricia_trie_node_reader.h
@@ -156,6 +156,8 @@
 
     void fetchNodeInfoFromBufferAndProcessMovedNode(const int nodePos, const int maxCodePointCount,
             int *const outCodePoints);
+
+    void invalidatePtNodeInfo();
 };
 } // namespace latinime
 #endif /* LATINIME_DYNAMIC_PATRICIA_TRIE_NODE_READER_H */