Implement support of encrypted elements in configuration file

docs/en/operations/configuration-files.md

@@ -65,6 +65,40 @@ XML substitution example:
 
 Substitutions can also be performed from ZooKeeper. To do this, specify the attribute `from_zk = "/path/to/node"`. The element value is replaced with the contents of the node at `/path/to/node` in ZooKeeper. You can also put an entire XML subtree on the ZooKeeper node and it will be fully inserted into the source element.
 
+## Encrypting Configuration {#encryption}
+
+You can use symmetric encryption to encrypt a configuration element, for example, a password field. To do so, first configure the [encryption codec](../sql-reference/statements/create/table.md#encryption-codecs), then add attribute `encryption_codec` with the name of the encryption codec as value to the element to encrypt.
+
+Unlike attributes `from_zk`, `from_env` and `incl` (or element `include`), no substitution, i.e. decryption of the encrypted value, is performed in the preprocessed file. Decryption happens only at runtime in the server process.
+
+Example:
+
+```xml
+<clickhouse>
+    <encryption_codecs>
+        <aes_128_gcm_siv>
+            <key_hex>00112233445566778899aabbccddeeff</key_hex>
+        </aes_128_gcm_siv>
+    </encryption_codecs>
+    <interserver_http_credentials>
+        <user>admin</user>
+        <password encryption_codec="AES_128_GCM_SIV">961F000000040000000000EEDDEF4F453CFE6457C4234BD7C09258BD651D85</password>
+    </interserver_http_credentials>
+</clickhouse>
+```
+
+To get the encrypted value `encrypt_decrypt` example application may be used.
+
+Example:
+
+``` bash
+./encrypt_decrypt /etc/clickhouse-server/config.xml -e AES_128_GCM_SIV abcd
+```
+
+``` text
+961F000000040000000000EEDDEF4F453CFE6457C4234BD7C09258BD651D85
+```
+
 ## User Settings {#user-settings}
 
 The `config.xml` file can specify a separate config with user settings, profiles, and quotas. The relative path to this config is set in the `users_config` element. By default, it is `users.xml`. If `users_config` is omitted, the user settings, profiles, and quotas are specified directly in `config.xml`.

docs/ru/operations/configuration-files.md

@@ -85,6 +85,40 @@ $ cat /etc/clickhouse-server/users.d/alice.xml
 
 Сервер следит за изменениями конфигурационных файлов, а также файлов и ZooKeeper-узлов, которые были использованы при выполнении подстановок и переопределений, и перезагружает настройки пользователей и кластеров на лету. То есть, можно изменять кластера, пользователей и их настройки без перезапуска сервера.
 
+## Шифрование {#encryption}
+
+Вы можете использовать симметричное шифрование для зашифровки элемента конфигурации, например, поля password. Чтобы это сделать, сначала настройте [кодек шифрования](../sql-reference/statements/create/table.md#encryption-codecs), затем добавьте аттибут`encryption_codec` с именем кодека шифрования как значение к элементу, который надо зашифровать.
+
+В отличии от аттрибутов `from_zk`, `from_env` и `incl` (или элемента `include`), подстановка, т.е. расшифровка зашифрованного значения, не выподняется в файле предобработки. Расшифровка происходит только во время исполнения в серверном процессе.
+
+Пример:
+
+```xml
+<clickhouse>
+    <encryption_codecs>
+        <aes_128_gcm_siv>
+            <key_hex>00112233445566778899aabbccddeeff</key_hex>
+        </aes_128_gcm_siv>
+    </encryption_codecs>
+    <interserver_http_credentials>
+        <user>admin</user>
+        <password encryption_codec="AES_128_GCM_SIV">961F000000040000000000EEDDEF4F453CFE6457C4234BD7C09258BD651D85</password>
+    </interserver_http_credentials>
+</clickhouse>
+```
+
+Чтобы получить зашифрованное значение может быть использовано приложение-пример `encrypt_decrypt` .
+
+Пример:
+
+``` bash
+./encrypt_decrypt /etc/clickhouse-server/config.xml -e AES_128_GCM_SIV abcd
+```
+
+``` text
+961F000000040000000000EEDDEF4F453CFE6457C4234BD7C09258BD651D85
+```
+
 ## Примеры записи конфигурации на YAML {#example}
 
 Здесь можно рассмотреть пример реальной конфигурации записанной на YAML: [config.yaml.example](https://github.com/ClickHouse/ClickHouse/blob/master/programs/server/config.yaml.example).

programs/keeper/CMakeLists.txt

@@ -94,6 +94,7 @@ if (BUILD_STANDALONE_KEEPER)
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressedReadBuffer.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressedReadBufferFromFile.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressedWriteBuffer.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressionCodecEncrypted.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressionCodecLZ4.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressionCodecMultiple.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/../../src/Compression/CompressionCodecNone.cpp

src/Common/Config/ConfigProcessor.cpp

@@ -27,6 +27,14 @@
 #include <IO/WriteBufferFromString.h>
 #include <IO/Operators.h>
 
+#if USE_SSL
+#include <format>
+#include <IO/BufferWithOwnMemory.h>
+#include <Compression/ICompressionCodec.h>
+#include <Compression/CompressionCodecEncrypted.h>
+#include <boost/algorithm/hex.hpp>
+#endif
+
 #define PREPROCESSED_SUFFIX "-preprocessed"
 
 namespace fs = std::filesystem;
@@ -40,6 +48,9 @@ namespace ErrorCodes
 {
     extern const int FILE_DOESNT_EXIST;
     extern const int CANNOT_LOAD_CONFIG;
+#if USE_SSL
+    extern const int BAD_ARGUMENTS;
+#endif
 }
 
 /// For cutting preprocessed path to this base
@@ -171,6 +182,72 @@ static void mergeAttributes(Element & config_element, Element & with_element)
     with_element_attributes->release();
 }
 
+#if USE_SSL
+
+std::string ConfigProcessor::encryptValue(const std::string & codec_name, const std::string & value)
+{
+    EncryptionMethod method = getEncryptionMethod(codec_name);
+    CompressionCodecEncrypted codec(method);
+
+    Memory<> memory;
+    memory.resize(codec.getCompressedReserveSize(static_cast<UInt32>(value.size())));
+    auto bytes_written = codec.compress(value.data(), static_cast<UInt32>(value.size()), memory.data());
+    auto encrypted_value = std::string(memory.data(), bytes_written);
+    std::string hex_value;
+    boost::algorithm::hex(encrypted_value.begin(), encrypted_value.end(), std::back_inserter(hex_value));
+    return hex_value;
+}
+
+std::string ConfigProcessor::decryptValue(const std::string & codec_name, const std::string & value)
+{
+    EncryptionMethod method = getEncryptionMethod(codec_name);
+    CompressionCodecEncrypted codec(method);
+
+    Memory<> memory;
+    std::string encrypted_value;
+
+    try
+    {
+        boost::algorithm::unhex(value, std::back_inserter(encrypted_value));
+    }
+    catch (const std::exception &)
+    {
+        throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cannot read encrypted text, check for valid characters [0-9a-fA-F] and length");
+    }
+
+    memory.resize(codec.readDecompressedBlockSize(encrypted_value.data()));
+    codec.decompress(encrypted_value.data(), static_cast<UInt32>(encrypted_value.size()), memory.data());
+    std::string decrypted_value = std::string(memory.data(), memory.size());
+    return decrypted_value;
+}
+
+void ConfigProcessor::decryptRecursive(Poco::XML::Node * config_root)
+{
+    for (Node * node = config_root->firstChild(); node; node = node->nextSibling())
+    {
+        if (node->nodeType() == Node::ELEMENT_NODE)
+        {
+            Element & element = dynamic_cast<Element &>(*node);
+            if (element.hasAttribute("encryption_codec"))
+            {
+                const NodeListPtr children = element.childNodes();
+                if (children->length() != 1)
+                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Encrypted node {} cannot contain nested elements", node->nodeName());
+
+                Node * text_node = node->firstChild();
+                if (text_node->nodeType() != Node::TEXT_NODE)
+                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Encrypted node {} should have text node", node->nodeName());
+
+                auto encryption_codec = element.getAttribute("encryption_codec");
+                text_node->setNodeValue(decryptValue(encryption_codec, text_node->getNodeValue()));
+            }
+            decryptRecursive(node);
+        }
+    }
+}
+
+#endif
+
 void ConfigProcessor::mergeRecursive(XMLDocumentPtr config, Node * config_root, const Node * with_root)
 {
     const NodeListPtr with_nodes = with_root->childNodes();
@@ -700,7 +777,19 @@ ConfigProcessor::LoadedConfig ConfigProcessor::loadConfigWithZooKeeperIncludes(
     return LoadedConfig{configuration, has_zk_includes, !processed_successfully, config_xml, path};
 }
 
-void ConfigProcessor::savePreprocessedConfig(const LoadedConfig & loaded_config, std::string preprocessed_dir)
+#if USE_SSL
+
+void ConfigProcessor::decryptEncryptedElements(LoadedConfig & loaded_config)
+{
+    CompressionCodecEncrypted::Configuration::instance().tryLoad(*loaded_config.configuration, "encryption_codecs");
+    Node * config_root = getRootNode(loaded_config.preprocessed_xml.get());
+    decryptRecursive(config_root);
+    loaded_config.configuration = new Poco::Util::XMLConfiguration(loaded_config.preprocessed_xml);
+}
+
+#endif
+
+void ConfigProcessor::savePreprocessedConfig(LoadedConfig & loaded_config, std::string preprocessed_dir)
 {
     try
     {
@@ -755,6 +844,12 @@ void ConfigProcessor::savePreprocessedConfig(const LoadedConfig & loaded_config,
     {
         LOG_WARNING(log, "Couldn't save preprocessed config to {}: {}", preprocessed_path, e.displayText());
     }
+
+#if USE_SSL
+    std::string preprocessed_file_name = fs::path(preprocessed_path).filename();
+    if (preprocessed_file_name == "config.xml" || preprocessed_file_name == std::format("config{}.xml", PREPROCESSED_SUFFIX))
+        decryptEncryptedElements(loaded_config);
+#endif
 }
 
 void ConfigProcessor::setConfigPath(const std::string & config_path)

src/Common/Config/ConfigProcessor.h

@@ -94,7 +94,7 @@ class ConfigProcessor
 
     /// Save preprocessed config to specified directory.
     /// If preprocessed_dir is empty - calculate from loaded_config.path + /preprocessed_configs/
-    void savePreprocessedConfig(const LoadedConfig & loaded_config, std::string preprocessed_dir);
+    void savePreprocessedConfig(LoadedConfig & loaded_config, std::string preprocessed_dir);
 
     /// Set path of main config.xml. It will be cut from all configs placed to preprocessed_configs/
     static void setConfigPath(const std::string & config_path);
@@ -106,6 +106,14 @@ class ConfigProcessor
     /// Is the file named as result of config preprocessing, not as original files.
     static bool isPreprocessedFile(const std::string & config_path);
 
+#if USE_SSL
+    /// Encrypt text value
+    static std::string encryptValue(const std::string & codec_name, const std::string & value);
+
+    /// Decrypt value
+    static std::string decryptValue(const std::string & codec_name, const std::string & value);
+#endif
+
     static inline const auto SUBSTITUTION_ATTRS = {"incl", "from_zk", "from_env"};
 
 private:
@@ -124,6 +132,13 @@ class ConfigProcessor
 
     using NodePtr = Poco::AutoPtr<Poco::XML::Node>;
 
+#if USE_SSL
+    void decryptRecursive(Poco::XML::Node * config_root);
+
+    /// Decrypt elements in config with specified encryption attributes
+    void decryptEncryptedElements(LoadedConfig & loaded_config);
+#endif
+
     void mergeRecursive(XMLDocumentPtr config, Poco::XML::Node * config_root, const Poco::XML::Node * with_root);
 
     void merge(XMLDocumentPtr config, XMLDocumentPtr with);

src/Common/Config/YAMLParser.cpp

@@ -110,9 +110,23 @@ namespace
                     }
                     else
                     {
-                        Poco::AutoPtr<Poco::XML::Element> xml_key = xml_document->createElement(key);
-                        parent_xml_node.appendChild(xml_key);
-                        processNode(value_node, *xml_key);
+                        if (key == "#text" && value_node.IsScalar())
+                        {
+                            for (Node * child_node = parent_xml_node.firstChild(); child_node; child_node = child_node->nextSibling())
+                                if (child_node->nodeType() == Node::TEXT_NODE)
+                                    throw Exception(ErrorCodes::CANNOT_PARSE_YAML,
+                                                    "YAMLParser has encountered node with several text nodes "
+                                                    "and cannot continue parsing of the file");
+                            std::string value = value_node.as<std::string>();
+                            Poco::AutoPtr<Poco::XML::Text> xml_value = xml_document->createTextNode(value);
+                            parent_xml_node.appendChild(xml_value);
+                        }
+                        else
+                        {
+                            Poco::AutoPtr<Poco::XML::Element> xml_key = xml_document->createElement(key);
+                            parent_xml_node.appendChild(xml_key);
+                            processNode(value_node, *xml_key);
+                        }
                     }
                 }
                 break;

src/Common/examples/CMakeLists.txt

@@ -82,3 +82,8 @@ endif()
 
 clickhouse_add_executable (interval_tree interval_tree.cpp)
 target_link_libraries (interval_tree PRIVATE dbms)
+
+if (ENABLE_SSL)
+    clickhouse_add_executable (encrypt_decrypt encrypt_decrypt.cpp)
+    target_link_libraries (encrypt_decrypt PRIVATE dbms)
+endif()

src/Common/examples/encrypt_decrypt.cpp

@@ -0,0 +1,61 @@
+#include <Common/Config/ConfigProcessor.h>
+#include <Compression/ICompressionCodec.h>
+#include <Compression/CompressionCodecEncrypted.h>
+#include <iostream>
+
+/** This test program encrypts or decrypts text values using a symmetric encryption codec like AES_128_GCM_SIV or AES_256_GCM_SIV.
+  * Keys for codecs are loaded from <encryption_codecs> section of configuration file.
+  *
+  * How to use:
+  *     ./encrypt_decrypt /etc/clickhouse-server/config.xml -e AES_128_GCM_SIV text_to_encrypt
+  */
+
+int main(int argc, char ** argv)
+{
+    try
+    {
+        if (argc != 5)
+        {
+            std::cerr << "Usage:" << std::endl
+                << "    " << argv[0] << " path action codec value" << std::endl
+                << "path: path to configuration file." << std::endl
+                << "action: -e for encryption and -d for decryption." << std::endl
+                << "codec: AES_128_GCM_SIV or AES_256_GCM_SIV." << std::endl << std::endl
+                << "Example:"  << std::endl
+                << "    ./encrypt_decrypt /etc/clickhouse-server/config.xml -e AES_128_GCM_SIV text_to_encrypt";
+            return 3;
+        }
+
+        std::string action = argv[2];
+        std::string codec_name = argv[3];
+        std::string value = argv[4];
+
+        DB::ConfigProcessor processor(argv[1], false, true);
+        auto loaded_config = processor.loadConfig();
+        DB::CompressionCodecEncrypted::Configuration::instance().tryLoad(*loaded_config.configuration, "encryption_codecs");
+
+        if (action == "-e")
+            std::cout << processor.encryptValue(codec_name, value) << std::endl;
+        else if (action == "-d")
+            std::cout << processor.decryptValue(codec_name, value) << std::endl;
+        else
+            std::cerr << "Unknown action: " << action << std::endl;
+    }
+    catch (Poco::Exception & e)
+    {
+        std::cerr << "Exception: " << e.displayText() << std::endl;
+        return 1;
+    }
+    catch (std::exception & e)
+    {
+        std::cerr << "std::exception: " << e.what() << std::endl;
+        return 3;
+    }
+    catch (...)
+    {
+        std::cerr << "Some exception" << std::endl;
+        return 2;
+    }
+
+    return 0;
+}