Custom SHA256 functionality added (#62)

* Support custom SHA 256 function

* Custom sha256 unit tests added

* custom SHA256 change log added

* change log updated

* Code analysis changes

* Build exe to run unit tests assosicated with SQlite and CUstome sha-256

* MISRA 18.4 rule applied

* CustomSHA functino pointer moved to constant file

Co-authored-by: Borgbyte <[email protected]>

Author: ZahidZafar

CHANGELOG.md

@@ -1,3 +1,6 @@
+21.11.3
+* Added functionality to set custom SHA256.
+
 21.11.2
 * Fixed a bug that occurred after trying to erase events from the SQLite database when there were none.
 * Fixed a bug with the checksum calculation.

CMakeLists.txt

@@ -9,6 +9,7 @@ project(countly VERSION ${COUNTLY_SDK_VERSION} LANGUAGES CXX)
 option(BUILD_SHARED_LIBS "Build shared libraries" ON)
 option(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS  "Create a module definition (.def) on Windows." ON)
 option(COUNTLY_USE_CUSTOM_HTTP "Use a custom HTTP library" OFF)
+option(COUNTLY_USE_CUSTOM_SHA256 "Use a custom SHA 256 library" OFF)
 option(COUNTLY_USE_SQLITE "Use SQLite" OFF)
 option(COUNTLY_BUILD_TESTS "Build test programs" OFF)
 option(COUNTLY_BUILD_SAMPLE "Build Sample programs" OFF)
@@ -35,12 +36,16 @@ target_link_libraries(countly Threads::Threads)
 
 target_include_directories(countly PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/vendor/json/include)
 
+if (COUNTLY_USE_CUSTOM_SHA256)
+  target_compile_definitions(countly PRIVATE COUNTLY_USE_CUSTOM_SHA256)
+else()
 if (APPLE)
   set(OPENSSL_ROOT_DIR "/usr/local/opt/openssl")
 endif()
 find_package(OpenSSL REQUIRED)
 target_include_directories(countly PRIVATE ${OPENSSL_INCLUDE_DIR})
 target_link_libraries(countly ${OPENSSL_LIBRARIES})
+endif()
 
 if(COUNTLY_USE_CUSTOM_HTTP)
   target_compile_definitions(countly PRIVATE COUNTLY_USE_CUSTOM_HTTP)
@@ -66,6 +71,9 @@ if(COUNTLY_BUILD_TESTS)
     target_compile_definitions(countly-tests PRIVATE COUNTLY_USE_SQLITE)
     target_include_directories(countly-tests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/vendor/sqlite)
   endif()
+  if(COUNTLY_USE_CUSTOM_SHA256)
+    target_compile_definitions(countly-tests PRIVATE COUNTLY_USE_CUSTOM_SHA256)
+  endif()
   target_include_directories(countly-tests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/vendor/doctest/doctest)
   target_include_directories(countly-tests PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/vendor/json/include)
   target_link_libraries(countly-tests countly)

README.md

@@ -85,3 +85,9 @@ make
 ./countly-tests
 ```
 
+To run unit tests associated with 'SQLITE' and 'Custom SHA-256' build executable with the options 
+`COUNTLY_USE_SQLITE` and `COUNTLY_BUILD_TESTS`:
+
+``` shell
+cmake -DCOUNTLY_BUILD_TESTS=1 -DCOUNTLY_USE_SQLITE=1 -DCOUNTLY_USE_CUSTOM_SHA256=1 -B build
+```

include/countly.hpp

@@ -23,6 +23,8 @@ using json = nlohmann::json;
 #undef ERROR
 #endif
 
+using namespace::countly_sdk;
+
 class Countly {
 public:
 	Countly();
@@ -50,6 +52,8 @@ class Countly {
 		bool success;
 		json data;
 	};
+	
+	void setSha256(SHA256Function fun);
 
 	using HTTPClientFunction = std::function<HTTPResponse(bool, const std::string&, const std::string&)>;
 	void setHTTPClient(HTTPClientFunction fun);
@@ -124,7 +128,7 @@ class Countly {
 
 	static std::string serializeForm(const std::map<std::string, std::string> data);
 
-	static std::string calculateChecksum(const std::string& salt, const std::string& data);
+	std::string calculateChecksum(const std::string& salt, const std::string& data);
 
 #ifdef COUNTLY_USE_SQLITE
 	void setDatabasePath(const std::string& path);
@@ -248,6 +252,7 @@ class Countly {
 
 	void updateLoop();
 
+	SHA256Function sha256_function;
 	LoggerFunction logger_function;
 	HTTPClientFunction http_client_function;
 

include/countly/constants.hpp

@@ -1,11 +1,18 @@
 #ifndef COUNTLY_CONSTANTS_HPP_
 #define COUNTLY_CONSTANTS_HPP_
 
+#include <string>
+#include <functional>
+
 #define COUNTLY_SDK_NAME "cpp-native-unknown"
 #define COUNTLY_SDK_VERSION "0.1.0"
 #define COUNTLY_API_VERSION "21.11.2"
 #define COUNTLY_POST_THRESHOLD 2000
 #define COUNTLY_KEEPALIVE_INTERVAL 3000
 #define COUNTLY_MAX_EVENTS_DEFAULT 200
 
+namespace countly_sdk {
+	using SHA256Function = std::function<std::string(const std::string&)>;
+}
+
 #endif

src/countly.cpp

@@ -6,7 +6,9 @@
 #include <iostream>
 #include <system_error>
 
+#ifndef COUNTLY_USE_CUSTOM_SHA256
 #include "openssl/sha.h"
+#endif
 
 #include "countly.hpp"
 
@@ -71,6 +73,12 @@ void Countly::setHTTPClient(HTTPClientFunction fun) {
 	mutex.unlock();
 }
 
+void Countly::setSha256(SHA256Function fun) {
+	mutex.lock();
+	sha256_function = fun;
+	mutex.unlock();
+}
+
 void Countly::setMetrics(const std::string& os, const std::string& os_version, const std::string& device,
 			 const std::string& resolution, const std::string& carrier, const std::string& app_version) {
 	json metrics = json::object();
@@ -793,8 +801,16 @@ static size_t countly_curl_write_callback(void *data, size_t byte_size, size_t n
 }
 
 std::string Countly::calculateChecksum(const std::string& salt, const std::string& data) {
-	unsigned char checksum[SHA256_DIGEST_LENGTH];
 	std::string salted_data = data + salt;
+#ifdef COUNTLY_USE_CUSTOM_SHA256
+	if (sha256_function == nullptr) {
+		log(Countly::LogLevel::FATAL, "Missing SHA 256 function");
+		return {};
+	}
+
+	return sha256_function(salted_data);
+#else
+	unsigned char checksum[SHA256_DIGEST_LENGTH];
 	SHA256_CTX sha256;
 
 	SHA256_Init(&sha256);
@@ -806,9 +822,8 @@ std::string Countly::calculateChecksum(const std::string& salt, const std::strin
 		checksum_stream << std::setfill('0') << std::setw(2) << std::hex << static_cast<int>(checksum[index]);
 	}
 
-	std::string calcualtedChecksum = checksum_stream.str();
-
-	return calcualtedChecksum;
+	return checksum_stream.str();
+#endif
 }
 
 Countly::HTTPResponse Countly::sendHTTP(std::string path, std::string data) {

tests/main.cpp

@@ -128,15 +128,41 @@ TEST_CASE("urlencoding is correct") {
 	//CHECK(Countly::encodeURL("测试") == "%E6%B5%8B%E8%AF%95"); // UTF-8 TODO: Needs to be fixed. This is throwing an exception.
 }
 
+#ifdef COUNTLY_USE_CUSTOM_SHA256
+std::string customChecksumCalculator(const std::string& data) {
+	std::string result = data.c_str();
+	result.append("-custom_sha");
+	return result;
+}
+
+TEST_CASE("custom sha256 function validation") {
+	Countly& countly = Countly::getInstance();
+
+	std::string salt = "test-salt";
+	std::string checksum = countly.calculateChecksum(salt, "hello world:");
+	CHECK(checksum == ""); // when customSha256 isn't set.
+
+	countly.setSha256(customChecksumCalculator);
+	salt = "test-salt";
+	checksum = countly.calculateChecksum(salt, "hello world:");
+	CHECK(checksum == "hello world:test-salt-custom_sha");
+
+	salt = "š ūļ ķ";
+	checksum = countly.calculateChecksum(salt, "测试:");
+	CHECK(checksum == "测试:š ūļ ķ-custom_sha");
+}
+#else
 TEST_CASE("checksum function validation") {
+	Countly& countly = Countly::getInstance();
 	std::string salt = "test-salt";
-	std::string checksum = Countly::calculateChecksum(salt, "hello world");
+	std::string checksum = countly.calculateChecksum(salt, "hello world");
 	CHECK(checksum == "aaf992c81357b0ed1bb404826e01825568126ebeb004c3bc690d3d8e0766a3cc");
 
 	salt = "š ūļ ķ";
-	checksum = Countly::calculateChecksum(salt, "测试");
+	checksum = countly.calculateChecksum(salt, "测试");
 	CHECK(checksum == "f51d24b0cb938e2f40b1f8609c62bf2508e24bcaa3b6b1a7fbf108d3c7f2f073");
 }
+#endif
 
 TEST_CASE("forms are serialized correctly") {
 	CHECK(Countly::serializeForm(std::map<std::string, std::string>({{"key1", "value1"}, {"key2", "value2"}})) == "key1=value1&key2=value2");