[Client] Verify integrity of credits file

apps/openmw/main.cpp

@@ -40,6 +40,7 @@
 
     Include additional headers for multiplayer purposes
 */
+#include <components/openmw-mp/ErrorMessages.hpp>
 #include <components/openmw-mp/Log.hpp>
 #include <components/openmw-mp/Utils.hpp>
 #include <components/openmw-mp/Version.hpp>
@@ -219,6 +220,34 @@ bool parseOptions (int argc, char** argv, OMW::Engine& engine, Files::Configurat
         End of tes3mp change (minor)
     */
 
+    /*
+        Start of tes3mp addition
+
+        Check for unmodified tes3mp-credits file; this makes it so people can't repackage official releases with
+        their own made-up credits, though it obviously has no bearing on unofficial releases that change
+        the checksum below
+    */
+    boost::filesystem::path folderPath(boost::filesystem::initial_path<boost::filesystem::path>());
+    folderPath = boost::filesystem::system_complete(boost::filesystem::path(argv[0])).remove_filename();
+    std::string creditsPath = folderPath.string() + "/tes3mp-credits";
+
+    unsigned int expectedChecksumInt = Utils::hexStrToInt(TES3MP_CREDITS_CHECKSUM);
+    bool hasValidCredits = Utils::doesFileHaveChecksum(creditsPath + ".md", expectedChecksumInt);
+
+    if (!hasValidCredits)
+        hasValidCredits = Utils::doesFileHaveChecksum(creditsPath + ".txt", expectedChecksumInt);
+
+    if (!hasValidCredits)
+    {
+        LOG_MESSAGE_SIMPLE(Log::LOG_FATAL, "The client is shutting down");
+        LOG_APPEND(Log::LOG_FATAL, "- %s", TES3MP_CREDITS_ERROR);
+        SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "tes3mp", TES3MP_CREDITS_ERROR, 0);
+        return false;
+    }
+    /*
+        End of tes3mp addition
+    */
+
     engine.setGrabMouse(!variables["no-grab"].as<bool>());
 
     // Font encoding settings