/** @file
  This is DCS recovery loader application

Copyright (c) 2016. Disk Cryptography Services for EFI (DCS), Alex Kolotnikov
Copyright (c) 2016. VeraCrypt, Mounir IDRASSI 

This program and the accompanying materials
are licensed and made available under the terms and conditions
of the GNU Lesser General Public License, version 3.0 (LGPL-3.0).

The full text of the license may be found at
https://opensource.org/licenses/LGPL-3.0
**/

#include <Uefi.h>
#include <Library/CommonLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DevicePathLib.h>
#include <Library/BaseMemoryLib.h>
#include <Guid/GlobalVariable.h>
#include "common/Tcdefs.h"

#ifdef _M_X64
#define ARCHdot L"x64."
#define ARCHdotEFI L"x64.efi"
#else
#define ARCHdot L"IA32."
#define ARCHdotEFI L"IA32.efi"
#endif

CONST CHAR8* g_szMsBootString = "bootmgfw.pdb";
CONST CHAR16* g_szVcBootString = L"VeraCrypt";

//////////////////////////////////////////////////////////////////////////
// Menu
//////////////////////////////////////////////////////////////////////////

BOOLEAN    gContiniue = TRUE;
PMENU_ITEM gMenu = NULL;


//////////////////////////////////////////////////////////////////////////
// EFI volume
//////////////////////////////////////////////////////////////////////////
UINTN        EfiBootVolumeIndex = 0;
EFI_FILE     *EfiBootVolume = NULL;
VOID
SelectEfiVolume() 
{
	UINTN        i;
	EFI_STATUS   res;
	EFI_FILE     *file;
	EFI_FILE     **efiVolumes;
	UINTN        efiVolumesCount = 0;
	if (EfiBootVolume != NULL) return;

	efiVolumes = MEM_ALLOC(sizeof(EFI_FILE*) * gFSCount);
	for (i = 0; i < gFSCount; ++i) {
		if (gFSHandles[i] == gFileRootHandle)
			continue;
		res = FileOpenRoot(gFSHandles[i], &file);
		if(EFI_ERROR(res)) { ERR_PRINT(L"FileOpenRoot %r\n", res); continue;}
		if (	!EFI_ERROR(FileExist(file, L"EFI\\Boot\\boot" ARCHdotEFI))
			||	!EFI_ERROR(FileExist(file, L"EFI\\Microsoft\\Boot\\bootmgfw.efi"))
			||	!EFI_ERROR(FileExist(file, L"EFI\\Microsoft\\Boot\\bootmgfw_ms.vc"))
			) 
		{
			efiVolumesCount++;
			efiVolumes[i] = file;
			EfiBootVolumeIndex = i;
			EfiBootVolume = file;
		}	else {
			FileClose(file);
		}
	}
	
	if (efiVolumesCount > 1)
	{
		for (i = 0; i < gFSCount; ++i) {
			OUT_PRINT(L"%H%d)%N ", i);
			if (efiVolumes[i] != NULL) {
				OUT_PRINT(L"%V [Boot] %N");
			}
			EfiPrintDevicePath(gFSHandles[i]);
			OUT_PRINT(L"\n");
		}

		do {
			EfiBootVolumeIndex = AskUINTN("Select EFI boot volume:", EfiBootVolumeIndex);
			if (EfiBootVolumeIndex >= gFSCount) continue;
			EfiBootVolume = efiVolumes[EfiBootVolumeIndex];
		} while (EfiBootVolume == NULL);
		
		/* free unused descriptors */
		for (i = 0; i < gFSCount; ++i) {
			if (efiVolumes[i] != NULL && efiVolumes[i] != EfiBootVolume) {
				FileClose(efiVolumes[i]);
			}
		}

		OUT_PRINT (L"\n");
	}
	
	
	MEM_FREE(efiVolumes);
}

//////////////////////////////////////////////////////////////////////////
// Actions
//////////////////////////////////////////////////////////////////////////
EFI_STATUS
ActionBootWinPE(IN VOID* ctx) {
	return EfiExec(NULL, L"EFI\\Boot\\WinPE_boot" ARCHdotEFI);
}

EFI_STATUS
ActionShell(IN VOID* ctx) {
	return EfiExec(NULL, L"EFI\\Shell\\Shell.efi");
}

EFI_STATUS
ActionDcsBoot(IN VOID* ctx) {
	SelectEfiVolume();
	if (EfiBootVolume == NULL) return EFI_NOT_READY;
	return EfiExec(gFSHandles[EfiBootVolumeIndex], L"EFI\\VeraCrypt\\DcsBoot.efi");
}

EFI_STATUS
ActionWindowsBoot(IN VOID* ctx) {
	if (AskConfirm("If Windows is encrypted, Windows original loader will fail to start.\r\nDo you want to continue? [N]", 1))
	{
		SelectEfiVolume();
		if (EfiBootVolume == NULL) return EFI_NOT_READY;
		if (!EFI_ERROR(FileExist(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw_ms.vc")))
			return EfiExec(gFSHandles[EfiBootVolumeIndex], L"EFI\\Microsoft\\Boot\\bootmgfw_ms.vc");
		else
		{
			if (!EFI_ERROR(FileExist(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw.efi")))
			{
				/* check if it is Microsoft one */
				UINT8*      fileData = NULL;
				UINTN       fileSize = 0;
				BOOLEAN		bFound = FALSE;
				if (!EFI_ERROR(FileLoad(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw.efi", &fileData, &fileSize)))
				{
					if ((fileSize > 32768) && !EFI_ERROR(MemoryHasPattern(fileData, fileSize, g_szMsBootString, AsciiStrLen(g_szMsBootString))))
					{
						bFound = TRUE;
					}
				}
				
				MEM_FREE(fileData);
				
				if (bFound)
					return EfiExec(gFSHandles[EfiBootVolumeIndex], L"EFI\\Microsoft\\Boot\\bootmgfw.efi");
			}
			
			/* copy our backup copy and then boot from it*/
			if (!EFI_ERROR(FileExist(NULL, L"\\EFI\\Boot\\original_boot" ARCHdot L"vc_backup")))
			{
				if (!EFI_ERROR(FileCopy(NULL, L"\\EFI\\Boot\\original_boot" ARCHdot L"vc_backup", EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw_ms.vc", 1024 * 1024)))
				{
					return EfiExec(gFSHandles[EfiBootVolumeIndex], L"EFI\\Microsoft\\Boot\\bootmgfw_ms.vc");
				}
			}

			ERR_PRINT(L"Could not find the original Windows loader\r\n");
			
			return EFI_NOT_READY;
		}
	}
	else
		return EFI_SUCCESS;
}

CHAR16* DcsBootBins[] = {
	L"EFI\\VeraCrypt\\DcsBoot.efi",
	L"EFI\\VeraCrypt\\DcsInt.dcs",
	L"EFI\\VeraCrypt\\DcsBml.dcs",
	L"EFI\\VeraCrypt\\DcsCfg.dcs",
	L"EFI\\VeraCrypt\\LegacySpeaker.dcs"
};

/**
Copy DCS binaries from rescue disk to EFI boot volume
*/
EFI_STATUS
ActionRestoreDcsLoader(IN VOID* ctx) {
	EFI_STATUS res = EFI_NOT_READY;
	UINTN i;
	SelectEfiVolume();
	if (EfiBootVolume == NULL) return EFI_NOT_READY;
	
	DirectoryCreate (EfiBootVolume, L"EFI\\VeraCrypt");
	
	for (i = 0; i < sizeof(DcsBootBins) / sizeof(CHAR16*); ++i) {
		res = FileCopy(NULL, DcsBootBins[i], EfiBootVolume, DcsBootBins[i], 1024 * 1024);
		if (EFI_ERROR(res)) return res;
	}
	/* restore standard boot file */
	if (!EFI_ERROR(FileExist(EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI)))
	{
		/* check if it is Microsoft one or ours */
		UINT8*      fileData = NULL;
		UINTN       fileSize = 0;
		res = EFI_SUCCESS;
		if (!EFI_ERROR(FileLoad(EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI, &fileData, &fileSize)))
		{
			if ((fileSize > 32768) && !EFI_ERROR(MemoryHasPattern(fileData, fileSize, g_szMsBootString, AsciiStrLen(g_szMsBootString))))
			{
				res = FileCopy(EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI, EfiBootVolume, L"\\EFI\\Boot\\original_boot" ARCHdot L"vc_backup", 1024 * 1024);
				if (!EFI_ERROR(res))
					res = FileCopy(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi", EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI, 1024 * 1024);				
			}
			else if ((fileSize <= 32768) && !EFI_ERROR(MemoryHasPattern(fileData, fileSize, g_szVcBootString, StrLen (g_szVcBootString) * 2)))
			{
				res = FileCopy(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi", EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI, 1024 * 1024);
			}
			MEM_FREE(fileData);
			
			if (EFI_ERROR(res)) return res;
		}		
	}
	else if (!EFI_ERROR(FileExist(EfiBootVolume, L"\\EFI\\Boot\\original_boot" ARCHdot L"vc_backup")))
	{
		res = FileCopy(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi", EfiBootVolume, L"EFI\\Boot\\boot" ARCHdotEFI, 1024 * 1024);
		if (EFI_ERROR(res)) return res;
	}
	
	if (!EFI_ERROR(FileExist(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw.efi")))
	{
		/* check if it is Microsoft one */
		UINT8*      fileData = NULL;
		UINTN       fileSize = 0;
		res = EFI_SUCCESS;
		if (!EFI_ERROR(FileLoad(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw.efi", &fileData, &fileSize)))
		{
			if ((fileSize > 32768) && !EFI_ERROR(MemoryHasPattern(fileData, fileSize, g_szMsBootString, AsciiStrLen(g_szMsBootString))))
			{
				res = FileCopy(EfiBootVolume, L"EFI\\Microsoft\\Boot\\bootmgfw.efi", EfiBootVolume, L"\\EFI\\Microsoft\\Boot\\bootmgfw_ms.vc", 1024 * 1024);				
			}

			MEM_FREE(fileData);
			
			if (EFI_ERROR(res)) return res;
		}

		res = FileCopy(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi", EfiBootVolume, L"\\EFI\\Microsoft\\Boot\\bootmgfw.efi", 1024 * 1024);
		if (EFI_ERROR(res)) return res;
	}
	else if (!EFI_ERROR(FileExist(EfiBootVolume, L"\\EFI\\Microsoft\\Boot\\bootmgfw_ms.vc")))		
	{
		res = FileCopy(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi", EfiBootVolume, L"\\EFI\\Microsoft\\Boot\\bootmgfw.efi", 1024 * 1024);
		if (EFI_ERROR(res)) return res;
	}
	
	OUT_PRINT (L"\nVeraCrypt Loader restored to disk successfully\n\n");
	
	return EFI_SUCCESS;
}

CHAR16* sDcsBootEfi = L"EFI\\VeraCrypt\\DcsBoot.efi";
CHAR16* sDcsBootEfiDesc = L"VeraCrypt(DCS) loader";
/**
Update boot menu
*/
EFI_STATUS
ActionRestoreDcsBootMenu(IN VOID* ctx)
{
	EFI_STATUS res = EFI_NOT_READY;
	SelectEfiVolume();
	if (EfiBootVolume == NULL) return EFI_NOT_READY;
	// Prepare BootDC5B
	res = BootMenuItemCreate(L"BootDC5B", sDcsBootEfiDesc, gFSHandles[EfiBootVolumeIndex], sDcsBootEfi, TRUE);
	if (EFI_ERROR(res)) return res;
	res = BootOrderInsert(L"BootOrder", 0, 0x0DC5B);
	return res;
}

EFI_STATUS
ActionRemoveDcsBootMenu(IN VOID* ctx)
{
	EFI_STATUS res = EFI_NOT_READY;
	BootMenuItemRemove(L"BootDC5B");
	res = BootOrderRemove(L"BootOrder", 0x0DC5B);
	return res;
}

/** 
Copy DcsProp from rescue disk to EFI boot volume
*/
EFI_STATUS
ActionRestoreDcsProp(IN VOID* ctx) {
	SelectEfiVolume();
	if (EfiBootVolume == NULL) return EFI_NOT_READY;
	return FileCopy(NULL, L"EFI\\VeraCrypt\\DcsProp", EfiBootVolume, L"EFI\\VeraCrypt\\DcsProp", 1024*1024);
}

#define OPT_OS_DECRYPT L"-osdecrypt"
#define OPT_OS_RESTORE_KEY L"-osrestorekey"

CHAR16* sOSDecrypt = OPT_OS_DECRYPT;
CHAR16* sOSRestoreKey = OPT_OS_RESTORE_KEY;
CHAR16* sDcsCfg = L"EFI\\VeraCrypt\\DcsCfg.dcs";

EFI_STATUS
ActionRestoreHeader(IN VOID* ctx) {
	EFI_STATUS res = EFI_NOT_READY;
	res = EfiSetVar(L"dcscfgcmd", NULL, sOSRestoreKey, StrSize(sOSRestoreKey), EFI_VARIABLE_BOOTSERVICE_ACCESS);
	return EfiExec(NULL, sDcsCfg);
}

EFI_STATUS
ActionDecryptOS(IN VOID* ctx) {
	EFI_STATUS res = EFI_NOT_READY;
	res = EfiSetVar(L"dcscfgcmd", NULL, sOSDecrypt, StrSize(sOSDecrypt), EFI_VARIABLE_BOOTSERVICE_ACCESS);
	return EfiExec(NULL, sDcsCfg);
}

EFI_STATUS
ActionExit(IN VOID* ctx) {
	gContiniue = FALSE;
	return EFI_SUCCESS;
}

EFI_STATUS
ActionHelp(IN VOID* ctx) {
OUT_PRINT(L"\
%HRescue disk for VeraCrypt OS encryption%N\n\r\
Help message to be defined\n\r\
");
	return EFI_SUCCESS;
}

/**
The actual entry point for the application.

@param[in] ImageHandle    The firmware allocated handle for the EFI image.
@param[in] SystemTable    A pointer to the EFI System Table.

@retval EFI_SUCCESS       The entry point executed successfully.
@retval other             Some error occur when executing this entry point.

**/
EFI_STATUS
EFIAPI
DcsReMain(
   IN EFI_HANDLE        ImageHandle,
   IN EFI_SYSTEM_TABLE  *SystemTable
   )
{
   EFI_STATUS          res;
	EFI_INPUT_KEY       key;
	PMENU_ITEM          item = gMenu;
	InitBio();
   res = InitFS();
   if (EFI_ERROR(res)) {
      ERR_PRINT(L"InitFS %r\n", res);
		return res;
   }
   
	if (!EFI_ERROR(DirectoryExists(NULL, L"EFI\\VeraCrypt")))
	{
		item = DcsMenuAppend(NULL, L"Decrypt OS", 'd', ActionDecryptOS, NULL);
		gMenu = item;
		item = DcsMenuAppend(item, L"Restore VeraCrypt loader to boot menu", 'm', ActionRestoreDcsBootMenu, NULL);
		item = DcsMenuAppend(item, L"Remove VeraCrypt loader from boot menu", 'z' , ActionRemoveDcsBootMenu, NULL);

		if (!EFI_ERROR(FileExist(NULL, L"EFI\\VeraCrypt\\DcsProp"))) {
			item = DcsMenuAppend(item, L"Restore VeraCrypt loader configuration to system disk", 'c', ActionRestoreDcsProp, NULL);
		}

		if (!EFI_ERROR(FileExist(NULL, L"EFI\\VeraCrypt\\svh_bak"))) {
			item = DcsMenuAppend(item, L"Restore OS header keys", 'k', ActionRestoreHeader, NULL);
		}

		if (!EFI_ERROR(FileExist(NULL, L"EFI\\VeraCrypt\\DcsBoot.efi"))) {
			item = DcsMenuAppend(item, L"Restore VeraCrypt loader binaries to system disk", 'r', ActionRestoreDcsLoader, NULL);
			item = DcsMenuAppend(item, L"Boot VeraCrypt loader from rescue disk", 'v', ActionDcsBoot, NULL);
		}
		
		item = DcsMenuAppend(item, L"Boot Original Windows Loader", 'o', ActionWindowsBoot, NULL);

		if (!EFI_ERROR(FileExist(NULL, L"EFI\\Boot\\WinPE_boot" ARCHdotEFI))) {
			item = DcsMenuAppend(item, L"Boot Windows PE from rescue disk", 'w', ActionBootWinPE, NULL);
		}

		if (!EFI_ERROR(FileExist(NULL, L"EFI\\Shell\\Shell.efi"))) {
			item = DcsMenuAppend(item, L"Boot Shell.efi from rescue disk", 's', ActionShell, NULL);
		}

		item = DcsMenuAppend(item, L"Help", 'h', ActionHelp, NULL);
		item = DcsMenuAppend(item, L"Exit", 'e', ActionExit, NULL);
		OUT_PRINT(L"%V%a rescue disk %a%N\n", TC_APP_NAME, VERSION_STRING);
		gBS->SetWatchdogTimer(0, 0, 0, NULL);
		do {
			DcsMenuPrint(gMenu);
			item = NULL;
			key.UnicodeChar = 0;
			while (item == NULL) {
				item = gMenu;
				key = GetKey();
				while (item != NULL) {
					if (item->Select == key.UnicodeChar) break;
					item = item->Next;
				}
			}
			OUT_PRINT(L"%c\n",key.UnicodeChar);
			res = item->Action(item->Context);
			if (EFI_ERROR(res)) {
				ERR_PRINT(L"%r\n", res);
			}
		} while (gContiniue);
	}
	else
	{
		/* No VeraCrypt folder. Boot directly from the hard drive */
		res = ActionDcsBoot (NULL);
		if (EFI_ERROR(res)) {
			ERR_PRINT(L"%r\n", res);
		}
	}
	return EFI_INVALID_PARAMETER;
}