Fix: DataLakes JSON parser depth limit for Delta/Iceberg metadata (stable-25.8)

src/Storages/ObjectStorage/DataLakes/DeltaLakeMetadata.cpp

@@ -2,6 +2,7 @@
 #include <Storages/ObjectStorage/DataLakes/DeltaLakeMetadata.h>
 #include <Storages/ObjectStorage/Utils.h>
 #include <base/JSON.h>
+#include <Core/Defines.h>
 #include "config.h"
 
 #if USE_PARQUET
@@ -260,6 +261,9 @@ struct DeltaLakeMetadataImpl
                 continue;
 
             Poco::JSON::Parser parser;
+            /// Bound the parser depth so a deeply nested metadata/schema JSON is rejected cleanly
+            /// instead of overflowing the native stack in Poco's recursive parser.
+            parser.setDepth(DBMS_DEFAULT_MAX_PARSER_DEPTH);
             Poco::Dynamic::Var json = parser.parse(json_str);
             const Poco::JSON::Object::Ptr & object = json.extract<Poco::JSON::Object::Ptr>();
 
@@ -540,6 +544,7 @@ struct DeltaLakeMetadataImpl
             if (!metadata.empty())
             {
                 Poco::JSON::Parser parser;
+                parser.setDepth(DBMS_DEFAULT_MAX_PARSER_DEPTH);
                 Poco::Dynamic::Var json = parser.parse(metadata);
                 const Poco::JSON::Object::Ptr & object = json.extract<Poco::JSON::Object::Ptr>();
 

src/Storages/ObjectStorage/DataLakes/Iceberg/ManifestFile.cpp

@@ -14,6 +14,7 @@
 
 #include <Core/TypeId.h>
 #include <DataTypes/DataTypesDecimal.h>
+#include <Core/Defines.h>
 #include <Poco/JSON/Parser.h>
 #include <Storages/ColumnsDescription.h>
 #include <Parsers/ASTFunction.h>
@@ -175,6 +176,9 @@ ManifestFileContent::ManifestFileContent(
             ErrorCodes::ICEBERG_SPECIFICATION_VIOLATION, "Required columns are not found in manifest file: {}", f_sequence_number);
 
     Poco::JSON::Parser parser;
+    /// Bound the parser depth so deeply nested partition-spec/schema JSON is rejected cleanly
+    /// instead of overflowing the native stack in Poco's recursive parser.
+    parser.setDepth(DBMS_DEFAULT_MAX_PARSER_DEPTH);
 
     auto partition_spec_json_string = manifest_file_deserializer.tryGetAvroMetadataValue("partition-spec");
     if (!partition_spec_json_string.has_value())

src/Storages/ObjectStorage/DataLakes/Iceberg/Utils.cpp

@@ -22,6 +22,7 @@
 #include <Storages/ColumnsDescription.h>
 #include <base/types.h>
 #include <Core/ColumnsWithTypeAndName.h>
+#include <Core/Defines.h>
 #include <Storages/ObjectStorage/DataLakes/Iceberg/IcebergWrites.h>
 #include <config.h>
 
@@ -300,6 +301,9 @@ Poco::JSON::Object::Ptr getMetadataJSONObject(
         metadata_json_str = create_fn();
 
     Poco::JSON::Parser parser; /// For some reason base/base/JSON.h can not parse this json file
+    /// Bound the parser depth so a deeply nested (attacker-controlled) metadata JSON is rejected
+    /// cleanly instead of overflowing the native stack in Poco's recursive parser.
+    parser.setDepth(DBMS_DEFAULT_MAX_PARSER_DEPTH);
     Poco::Dynamic::Var json = parser.parse(metadata_json_str);
     return json.extract<Poco::JSON::Object::Ptr>();
 }