OpenCorePkg/Library/OcBootManagementLib/DmgBootSupport.c

/** @file
  Copyright (C) 2019, vit9696. All rights reserved.

  All rights reserved.

  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/

#include "BootManagementInternal.h"

#include <Guid/FileInfo.h>

#include <Library/OcAppleSecureBootLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/DevicePathLib.h>
#include <Library/FileHandleLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/OcAppleKeysLib.h>
#include <Library/OcFileLib.h>
#include <Library/OcStringLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>

STATIC
EFI_DEVICE_PATH_PROTOCOL *
InternalGetFirstDeviceBootFilePath (
  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DmgDevicePath,
  IN UINTN                           DmgDevicePathSize
  )
{
  EFI_DEVICE_PATH_PROTOCOL  *BootDevicePath;

  EFI_STATUS  Status;
  INTN        CmpResult;

  CONST EFI_DEVICE_PATH_PROTOCOL  *FsDevicePath;
  UINTN                           FsDevicePathSize;

  UINTN       NumHandles;
  EFI_HANDLE  *HandleBuffer;
  UINTN       Index;

  ASSERT (DmgDevicePath != NULL);
  ASSERT (DmgDevicePathSize >= END_DEVICE_PATH_LENGTH);

  BootDevicePath = NULL;

  Status = gBS->LocateHandleBuffer (
                  ByProtocol,
                  &gEfiSimpleFileSystemProtocolGuid,
                  NULL,
                  &NumHandles,
                  &HandleBuffer
                  );
  if (EFI_ERROR (Status)) {
    return NULL;
  }

  for (Index = 0; Index < NumHandles; ++Index) {
    Status = gBS->HandleProtocol (
                    HandleBuffer[Index],
                    &gEfiDevicePathProtocolGuid,
                    (VOID **)&FsDevicePath
                    );
    if (EFI_ERROR (Status)) {
      continue;
    }

    FsDevicePathSize = GetDevicePathSize (FsDevicePath);

    if (FsDevicePathSize < DmgDevicePathSize) {
      continue;
    }

    CmpResult = CompareMem (
                  FsDevicePath,
                  DmgDevicePath,
                  (DmgDevicePathSize - END_DEVICE_PATH_LENGTH)
                  );
    if (CmpResult != 0) {
      continue;
    }

    Status = OcBootPolicyGetBootFileEx (
               HandleBuffer[Index],
               gAppleBootPolicyPredefinedPaths,
               gAppleBootPolicyNumPredefinedPaths,
               &BootDevicePath
               );
    if (!EFI_ERROR (Status)) {
      break;
    }

    BootDevicePath = NULL;
  }

  FreePool (HandleBuffer);

  return BootDevicePath;
}

STATIC
EFI_DEVICE_PATH_PROTOCOL *
InternalGetDiskImageBootFile (
  OUT INTERNAL_DMG_LOAD_CONTEXT  *Context,
  IN  OC_DMG_LOADING_SUPPORT     DmgLoading,
  IN  UINTN                      DmgFileSize,
  IN  VOID                       *ChunklistBuffer OPTIONAL,
  IN  UINT32                     ChunklistBufferSize OPTIONAL
  )
{
  EFI_DEVICE_PATH_PROTOCOL  *DevPath;

  BOOLEAN                     Result;
  OC_APPLE_CHUNKLIST_CONTEXT  ChunklistContext;

  CONST EFI_DEVICE_PATH_PROTOCOL  *DmgDevicePath;
  UINTN                           DmgDevicePathSize;

  ASSERT (Context != NULL);
  ASSERT (DmgFileSize > 0);

  if (DmgLoading == OcDmgLoadingAppleSigned) {
    if (ChunklistBuffer == NULL) {
      DEBUG ((DEBUG_WARN, "OCB: Missing DMG signature, aborting\n"));
      return NULL;
    }

    ASSERT (ChunklistBufferSize > 0);

    Result = OcAppleChunklistInitializeContext (
               &ChunklistContext,
               ChunklistBuffer,
               ChunklistBufferSize
               );
    if (!Result) {
      DEBUG ((
        DEBUG_INFO,
        "OCB: Failed to initialise DMG Chunklist context\n"
        ));
      return NULL;
    }

    //
    // FIXME: Properly abstract OcAppleKeysLib.
    //
    Result = OcAppleChunklistVerifySignature (
               &ChunklistContext,
               PkDataBase[0].PublicKey
               );

    if (!Result) {
      Result = OcAppleChunklistVerifySignature (
                 &ChunklistContext,
                 PkDataBase[1].PublicKey
                 );
    }

    if (!Result) {
      DEBUG ((DEBUG_WARN, "OCB: DMG is not trusted, aborting\n"));
      return NULL;
    }

    Result = OcAppleDiskImageVerifyData (
               Context->DmgContext,
               &ChunklistContext
               );
    if (!Result) {
      DEBUG ((DEBUG_WARN, "OCB: DMG has been altered\n"));
      return NULL;
    }
  }

  Context->BlockIoHandle = OcAppleDiskImageInstallBlockIo (
                             Context->DmgContext,
                             DmgFileSize,
                             &DmgDevicePath,
                             &DmgDevicePathSize
                             );
  if (Context->BlockIoHandle == NULL) {
    DEBUG ((DEBUG_INFO, "OCB: Failed to install DMG Block I/O\n"));
    return NULL;
  }

  DevPath = InternalGetFirstDeviceBootFilePath (
              DmgDevicePath,
              DmgDevicePathSize
              );
  if (DevPath == NULL) {
    DEBUG ((DEBUG_INFO, "OCB: Failed to get bootable file off DMG\n"));

    OcAppleDiskImageUninstallBlockIo (
      Context->DmgContext,
      Context->BlockIoHandle
      );
    return NULL;
  }

  return DevPath;
}

STATIC
EFI_FILE_INFO *
InternalFindFirstDmgFileName (
  IN  EFI_FILE_PROTOCOL  *Directory,
  OUT UINTN              *FileNameLen
  )
{
  EFI_STATUS     Status;
  EFI_FILE_INFO  *FileInfo;
  BOOLEAN        NoFile;
  UINTN          ExtOffset;
  UINTN          Length;
  INTN           Result;

  ASSERT (Directory != NULL);

  for (
       Status = FileHandleFindFirstFile (Directory, &FileInfo), NoFile = FALSE;
       (!EFI_ERROR (Status) && !NoFile);
       Status = FileHandleFindNextFile (Directory, FileInfo, &NoFile)
       )
  {
    if ((FileInfo->Attribute & EFI_FILE_DIRECTORY) != 0) {
      continue;
    }

    //
    // Discard filenames that do not contain characters prior to .dmg extension.
    //
    Length = StrLen (FileInfo->FileName);
    if (Length <= L_STR_LEN (L".dmg")) {
      continue;
    }

    ExtOffset = Length - L_STR_LEN (L".dmg");
    Result    = StrCmp (&FileInfo->FileName[ExtOffset], L".dmg");
    if (Result == 0) {
      if (FileNameLen != NULL) {
        *FileNameLen = ExtOffset;
      }

      return FileInfo;
    }
  }

  return NULL;
}

STATIC
EFI_FILE_INFO *
InternalFindDmgChunklist (
  IN EFI_FILE_PROTOCOL  *Directory,
  IN CONST CHAR16       *DmgFileName,
  IN UINTN              DmgFileNameLen
  )
{
  EFI_STATUS     Status;
  EFI_FILE_INFO  *FileInfo;
  BOOLEAN        NoFile;
  UINTN          NameLen;
  INTN           Result;
  UINTN          ChunklistFileNameLen;

  ChunklistFileNameLen = (DmgFileNameLen + L_STR_LEN (".chunklist"));

  for (
       Status = FileHandleFindFirstFile (Directory, &FileInfo), NoFile = FALSE;
       (!EFI_ERROR (Status) && !NoFile);
       Status = FileHandleFindNextFile (Directory, FileInfo, &NoFile)
       )
  {
    if ((FileInfo->Attribute & EFI_FILE_DIRECTORY) != 0) {
      continue;
    }

    NameLen = StrLen (FileInfo->FileName);

    if (NameLen != ChunklistFileNameLen) {
      continue;
    }

    Result = StrnCmp (FileInfo->FileName, DmgFileName, DmgFileNameLen);
    if (Result != 0) {
      continue;
    }

    Result = StrCmp (&FileInfo->FileName[DmgFileNameLen], L".chunklist");
    if (Result == 0) {
      DEBUG ((
        DEBUG_INFO,
        "OCB: Found chunklist %s for DMG %s[%d]\n",
        FileInfo->FileName,
        DmgFileName,
        DmgFileNameLen
        ));
      return FileInfo;
    }
  }

  DEBUG ((
    DEBUG_INFO,
    "OCB: Found no chunklist for DMG %s[%d]\n",
    DmgFileName,
    DmgFileNameLen
    ));
  return NULL;
}

EFI_DEVICE_PATH_PROTOCOL *
InternalLoadDmg (
  IN OUT INTERNAL_DMG_LOAD_CONTEXT            *Context,
  IN     OC_DMG_LOADING_SUPPORT               DmgLoading,
  IN     OC_APPLE_DISK_IMAGE_PRELOAD_CONTEXT  *DmgPreloadContext
  )
{
  EFI_DEVICE_PATH_PROTOCOL  *DevPath;

  EFI_STATUS  Status;
  BOOLEAN     Result;

  EFI_FILE_PROTOCOL  *DmgDir;

  UINTN              DmgFileNameLen;
  EFI_FILE_INFO      *DmgFileInfo;
  EFI_FILE_PROTOCOL  *DmgFile;
  UINT32             DmgFileSize;

  EFI_FILE_INFO      *ChunklistFileInfo;
  EFI_FILE_PROTOCOL  *ChunklistFile;
  UINT32             ChunklistFileSize;
  VOID               *ChunklistBuffer;

  CHAR16  *DevPathText;

  ASSERT (Context != NULL);

  if (DmgPreloadContext->DmgContext != NULL) {
    Context->DmgContext = DmgPreloadContext->DmgContext;
    DmgFileSize         = DmgPreloadContext->DmgFileSize;
  } else {
    if (DmgPreloadContext->DmgFile != NULL) {
      DmgFile     = DmgPreloadContext->DmgFile;
      DmgFileSize = DmgPreloadContext->DmgFileSize;
    } else {
      DevPath = Context->DevicePath;
      Status  = OcOpenFileByDevicePath (
                  &DevPath,
                  &DmgDir,
                  EFI_FILE_MODE_READ,
                  EFI_FILE_DIRECTORY
                  );
      if (EFI_ERROR (Status)) {
        DevPathText = ConvertDevicePathToText (Context->DevicePath, FALSE, FALSE);
        DEBUG ((DEBUG_INFO, "OCB: Failed to open DMG directory %s\n", DevPathText));
        if (DevPathText != NULL) {
          FreePool (DevPathText);
        }

        return NULL;
      }

      DmgFileInfo = InternalFindFirstDmgFileName (DmgDir, &DmgFileNameLen);
      if (DmgFileInfo == NULL) {
        DevPathText = ConvertDevicePathToText (Context->DevicePath, FALSE, FALSE);
        DEBUG ((DEBUG_INFO, "OCB: Unable to find any DMG at %s\n"));
        if (DevPathText != NULL) {
          FreePool (DevPathText);
        }

        DmgDir->Close (DmgDir);
        return NULL;
      }

      Status = OcSafeFileOpen (
                 DmgDir,
                 &DmgFile,
                 DmgFileInfo->FileName,
                 EFI_FILE_MODE_READ,
                 0
                 );
      if (EFI_ERROR (Status)) {
        DEBUG ((
          DEBUG_INFO,
          "OCB: Failed to open DMG file %s - %r\n",
          DmgFileInfo->FileName,
          Status
          ));

        FreePool (DmgFileInfo);
        DmgDir->Close (DmgDir);
        return NULL;
      }

      Status = OcGetFileSize (DmgFile, &DmgFileSize);
      if (EFI_ERROR (Status)) {
        DEBUG ((
          DEBUG_INFO,
          "OCB: Failed to retrieve DMG file size - %r\n",
          Status
          ));

        FreePool (DmgFileInfo);
        DmgDir->Close (DmgDir);
        DmgFile->Close (DmgFile);
        return NULL;
      }
    }

    Context->DmgContext = AllocatePool (sizeof (*Context->DmgContext));
    if (Context->DmgContext == NULL) {
      DEBUG ((DEBUG_INFO, "OCB: Failed to allocate DMG context\n"));
      return NULL;
    }

    Result = OcAppleDiskImageInitializeFromFile (Context->DmgContext, DmgFile);

    DmgFile->Close (DmgFile);

    if (!Result) {
      DEBUG ((DEBUG_INFO, "OCB: Failed to initialise DMG from file\n"));

      if (DmgPreloadContext->DmgFile == NULL) {
        FreePool (DmgFileInfo);
        DmgDir->Close (DmgDir);
      }

      FreePool (Context->DmgContext);
      return NULL;
    }
  }

  ChunklistBuffer   = NULL;
  ChunklistFileSize = 0;
  if (  (DmgPreloadContext->DmgFile != NULL)
     || (DmgPreloadContext->DmgContext != NULL))
  {
    if (DmgPreloadContext->ChunklistBuffer != NULL) {
      ChunklistBuffer   = DmgPreloadContext->ChunklistBuffer;
      ChunklistFileSize = DmgPreloadContext->ChunklistFileSize;
    }
  } else {
    ChunklistFileInfo = InternalFindDmgChunklist (
                          DmgDir,
                          DmgFileInfo->FileName,
                          DmgFileNameLen
                          );
    if (ChunklistFileInfo != NULL) {
      Status = OcSafeFileOpen (
                 DmgDir,
                 &ChunklistFile,
                 ChunklistFileInfo->FileName,
                 EFI_FILE_MODE_READ,
                 0
                 );
      if (!EFI_ERROR (Status)) {
        Status = OcGetFileSize (ChunklistFile, &ChunklistFileSize);
        if (Status == EFI_SUCCESS) {
          ChunklistBuffer = AllocatePool (ChunklistFileSize);

          if (ChunklistBuffer == NULL) {
            ChunklistFileSize = 0;
          } else {
            Status = OcGetFileData (ChunklistFile, 0, ChunklistFileSize, ChunklistBuffer);
            if (EFI_ERROR (Status)) {
              FreePool (ChunklistBuffer);
              ChunklistBuffer   = NULL;
              ChunklistFileSize = 0;
            }
          }
        }

        ChunklistFile->Close (ChunklistFile);
      }

      FreePool (ChunklistFileInfo);
    }
  }

  if (  (DmgPreloadContext->DmgFile == NULL)
     && (DmgPreloadContext->DmgContext == NULL))
  {
    FreePool (DmgFileInfo);
    DmgDir->Close (DmgDir);
  }

  DevPath = InternalGetDiskImageBootFile (
              Context,
              DmgLoading,
              DmgFileSize,
              ChunklistBuffer,
              ChunklistFileSize
              );
  Context->DevicePath = DevPath;

  if (DevPath != NULL) {
    //
    // If we succeeded, we need to disable Apple Secure Boot, as DMG images
    // are currently only verified with the chunklist.
    //
    OcAppleSecureBootSetDmgLoading (TRUE);
  } else {
    DEBUG ((DEBUG_INFO, "OCB: Failed to retrieve boot file from DMG\n"));

    OcAppleDiskImageFreeFile (Context->DmgContext);
    FreePool (Context->DmgContext);
  }

  if (ChunklistBuffer != NULL) {
    FreePool (ChunklistBuffer);
  }

  return DevPath;
}

VOID
InternalUnloadDmg (
  IN INTERNAL_DMG_LOAD_CONTEXT  *DmgLoadContext
  )
{
  if (DmgLoadContext->DevicePath != NULL) {
    FreePool (DmgLoadContext->DevicePath);
    OcAppleDiskImageUninstallBlockIo (
      DmgLoadContext->DmgContext,
      DmgLoadContext->BlockIoHandle
      );
    OcAppleDiskImageFreeContext (DmgLoadContext->DmgContext);
    FreePool (DmgLoadContext->DmgContext);
    DmgLoadContext->DevicePath = NULL;
    //
    // This code should never execute, as with Apple Secure Boot
    // it should always reboot on failure, but just in case.
    //
    OcAppleSecureBootSetDmgLoading (FALSE);
  }
}