Refactor SteamAuth Caching System

+ Add dw_cacheTicket dvar
+ Automatically delete bad cache files

Author: SE2Dev

components/game_mod/com_files.cpp

@@ -151,3 +151,39 @@ int __cdecl FS_FOpenFileWriteToDir(const char *filename, const char *dir, const
 
 	return FS_FOpenFileWriteToDir_o(filename, dir, osbasepath);
 }
+
+unsigned __int64 FS_FileAge(const char* path)
+{
+	// Quick lambda for converting filetimes to ull
+	auto ft2uint64 = [](const FILETIME& ft)
+	{
+		ULARGE_INTEGER ul;
+		ul.LowPart = ft.dwLowDateTime;
+		ul.HighPart = ft.dwHighDateTime;
+		return ul.QuadPart;
+	};
+
+	HANDLE h = CreateFileA(path, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
+	if (h == INVALID_HANDLE_VALUE)
+		return UINT64_MAX;
+
+	// Retrieve the file times for the file
+	FILETIME create, access, write;
+	auto err = GetFileTime(h, &create, &access, &write);
+	CloseHandle(h);
+
+	// Abort if we couldn't get the filetime
+	if (!err)
+		return UINT64_MAX;
+
+	FILETIME sys_time;
+	GetSystemTimeAsFileTime(&sys_time);
+
+	auto age = (ft2uint64(sys_time) - ft2uint64(write)) / 10000;
+	return __int64(age);
+}
+
+unsigned __int64 FS_FileAge_Sec(const char* path)
+{
+	return FS_FileAge(path) / 1000;
+}

components/game_mod/com_files.h

@@ -93,3 +93,15 @@ int __cdecl FS_GetModList(char *listbuf, int bufsize);
 // Used only by Com_WriteConfigToFile and Com_WriteKeyConfigToFile
 //
 int __cdecl FS_FOpenFileWriteToDir(const char *filename, const char *dir, const char *osbasepath);
+
+//
+// Get the age of a file in milliseconds
+// returns UINT64_MAX if the file doesn't exist
+//
+unsigned __int64 FS_FileAge(const char* path);
+
+//
+// Get the age of a file in seconds
+// returns UINT64_MAX if the file doesn't exist
+//
+unsigned __int64 FS_FileAge_Sec(const char* path);

components/game_mod/dvar.cpp

@@ -19,6 +19,8 @@ dvar_s* com_developer_print = NULL;
 
 dvar_s* sv_showCommands = NULL;
 
+dvar_s* dw_cacheTicket = NULL;
+
 dvar_s* radiant_live = NULL;
 dvar_s* radiant_livePort = NULL;
 dvar_s* radiant_liveDebug = NULL;
@@ -92,6 +94,8 @@ void R_RegisterCustomDvars()
 	sv_showCommands = Dvar_RegisterBool("sv_showCommands", 0, 0, "Print client commands in the log file");
 
 	r_streamCheckAabb = Dvar_RegisterBool("r_streamCheckAabb", false, DVAR_CHEAT, "Enables runtime checking of the stream aabb tree");
+
+	dw_cacheTicket = Dvar_RegisterBool("dw_cacheTicket", true, DVAR_ARCHIVE, "Cache the SteamAuth ticket to the disk");
 }
 
 void* rtn_R_RegisterDvars = (void*)0x006CA283;

components/game_mod/dvar.h

@@ -208,6 +208,8 @@ extern dvar_s* com_developer_print;
 
 extern dvar_s* sv_showCommands;
 
+extern dvar_s* dw_cacheTicket;
+
 extern dvar_s* radiant_live;
 extern dvar_s* radiant_livePort;
 extern dvar_s* radiant_liveDebug;

components/game_mod/live_steam_client.cpp

@@ -70,6 +70,31 @@ namespace LiveSteam
 			return 1;
 		}
 
+		//
+		// Error handler lambda that automatically:
+		//  + frees the cache file handle
+		//  + deletes the cache file
+		//  + clears the memory cache
+		//
+		auto DeleteBadCache = [this, h](void)
+		{
+			// Close the file handle so we can actually delete the file
+			fclose(h);
+
+			DeleteFileA(AUTHCACHE_FILEPATH);
+			ClearCache();
+		};
+
+		//
+		// Check the age of the cache file
+		// If it's too old we need to delete it and clear the cache
+		//
+		if (FS_FileAge_Sec(AUTHCACHE_FILEPATH) > 60)
+		{
+			DeleteBadCache();
+			return 5;
+		}
+
 		// We only need to allocate a buffer for m_steamCookieKey if it doesn't already have one.
 		// Since m_steamCookieKeySize is constant, we don't need to worry about resizing the buffer
 		if (m_steamCookieKey == nullptr)
@@ -78,8 +103,7 @@ namespace LiveSteam
 		if (fread(m_steamCookieKey, 1, m_steamCookieKeySize, h) != m_steamCookieKeySize)
 		{
 			// Unable to read the correct number of bytes for the cookie key
-			fclose(h);
-			ClearCache();
+			DeleteBadCache();
 			return 2;
 		}
 
@@ -104,8 +128,7 @@ namespace LiveSteam
 		if (fread(m_steamAppTicket, 1, m_steamAppTicketSize, h) != m_steamAppTicketSize)
 		{
 			// Unable to read the correct number of bytes for the app ticket
-			fclose(h);
-			ClearCache();
+			DeleteBadCache();
 			return 3;
 		}
 
@@ -193,25 +216,36 @@ bool LiveSteamClient::GetRetrievedEncryptedAppTicket(void *ticketBuf, const unsi
 	auto steamUser = (*(void *(__cdecl **)())0x009A356C)();
 	auto getEncryptedAppTicket = *(bool(__thiscall **)(void *, void *, int, unsigned int *))(*(DWORD *)steamUser + 80);
 
-	// Use the real function if Steam had a good ticket
-	if (this->rawTicketResult == k_EResultOK)
+	bool useCache = dw_cacheTicket && dw_cacheTicket->current.enabled;
+
+	//
+	// Use the real function if one of the following conditions are met:
+	//	+ Steam had a good ticket
+	//	+ The caching subsystem is disabled
+	//
+	// Otherwise we fallback to using the cached ticket
+	//
+	if (this->rawTicketResult == k_EResultOK || !useCache)
 	{
 		if (getEncryptedAppTicket(steamUser, ticketBuf, ticketBufSize, ticketSize))
 		{
-			DBG_ASSERT(g_authService);
-			if (!g_authService)
+			if (useCache)
 			{
-				Com_DPrintf(1, "STEAM: Couldn't cache recieved auth ticket - g_authService is NULL\n");
-				return true;
-			}
-
-			// Update the cache with the generated ticket & DW cookie
-			g_authCache.UpdateCache(ticketBuf, *ticketSize, g_authService->m_steamCookieKey);
-			
-			// Commit the new cache contents to the disk
-			if (g_authCache.CommitCache() == 0)
-			{
-				Com_DPrintf(1, "STEAM: Wrote cached auth ticket\n");
+				DBG_ASSERT(g_authService);
+				if (!g_authService)
+				{
+					Com_DPrintf(1, "STEAM: Couldn't cache recieved auth ticket - g_authService is NULL\n");
+					return true;
+				}
+
+				// Update the cache with the generated ticket & DW cookie
+				g_authCache.UpdateCache(ticketBuf, *ticketSize, g_authService->m_steamCookieKey);
+
+				// Commit the new cache contents to the disk
+				if (g_authCache.CommitCache() == 0)
+				{
+					Com_DPrintf(1, "STEAM: Wrote cached auth ticket\n");
+				}
 			}
 
 			Com_DPrintf(1, "STEAM: Retrieved auth ticket from Steam, sending to DemonWare\n");
@@ -266,15 +300,21 @@ void LiveSteamClient::OnRequestEncryptedAppTicket(EncryptedAppTicketResponse_t *
 		break;
 	}
 
-	// If the request was rate limited, check if there's a cached ticket
-	if (pEncryptedAppTicketResponse->m_eResult == k_EResultLimitExceeded)
+	//
+	// Only use the caching subsystem if we explicitly have it enabled
+	//
+	if (dw_cacheTicket && dw_cacheTicket->current.enabled)
 	{
-		if (g_authCache.ValidateCache())
+		// If the request was rate limited, check if there's a cached ticket
+		if (pEncryptedAppTicketResponse->m_eResult == k_EResultLimitExceeded)
 		{
-			Com_DPrintf(1, "STEAM: Attempting to use cached auth ticket...\n");
+			if (g_authCache.ValidateCache())
+			{
+				Com_DPrintf(1, "STEAM: Attempting to use cached auth ticket...\n");
 
-			pEncryptedAppTicketResponse->m_eResult = k_EResultOK;
-			dwLogonSeAcquiredSteamTicket();
+				pEncryptedAppTicketResponse->m_eResult = k_EResultOK;
+				dwLogonSeAcquiredSteamTicket();
+			}
 		}
 	}