MdeModulePkg/Core/Dxe/FwVol/Ffs.c

   1 /** @file
   2   FFS file access utilities.
   3
   4 Copyright (c) 2006 - 2008, Intel Corporation. <BR>
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15
  16 #include <DxeMain.h>
  17
  18 #define PHYSICAL_ADDRESS_TO_POINTER(Address) ((VOID *)((UINTN)(Address)))
  19
  20
  21 /**
  22   Get the FFS file state by checking the highest bit set in the header's state field.
  23
  24   @param  ErasePolarity  Erase polarity attribute of the firmware volume
  25   @param  FfsHeader      Points to the FFS file header
  26
  27   @return FFS File state
  28
  29 **/
  30 EFI_FFS_FILE_STATE
  31 GetFileState (
  32   IN UINT8                ErasePolarity,
  33   IN EFI_FFS_FILE_HEADER  *FfsHeader
  34   )
  35 {
  36   EFI_FFS_FILE_STATE      FileState;
  37   UINT8                   HighestBit;
  38
  39   FileState = FfsHeader->State;
  40
  41   if (ErasePolarity != 0) {
  42     FileState = (EFI_FFS_FILE_STATE)~FileState;
  43   }
  44
  45   HighestBit = 0x80;
  46   while (HighestBit != 0 && ((HighestBit & FileState) == 0)) {
  47     HighestBit >>= 1;
  48   }
  49
  50   return (EFI_FFS_FILE_STATE)HighestBit;
  51 }
  52
  53
  54
  55 /**
  56   Check if a block of buffer is erased.
  57
  58   @param  ErasePolarity  Erase polarity attribute of the firmware volume
  59   @param  InBuffer       The buffer to be checked
  60   @param  BufferSize     Size of the buffer in bytes
  61
  62   @retval TRUE           The block of buffer is erased
  63   @retval FALSE          The block of buffer is not erased
  64
  65 **/
  66 BOOLEAN
  67 IsBufferErased (
  68   IN UINT8    ErasePolarity,
  69   IN VOID     *InBuffer,
  70   IN UINTN    BufferSize
  71   )
  72 {
  73   UINTN   Count;
  74   UINT8   EraseByte;
  75   UINT8   *Buffer;
  76
  77   if(ErasePolarity == 1) {
  78     EraseByte = 0xFF;
  79   } else {
  80     EraseByte = 0;
  81   }
  82
  83   Buffer = InBuffer;
  84   for (Count = 0; Count < BufferSize; Count++) {
  85     if (Buffer[Count] != EraseByte) {
  86       return FALSE;
  87     }
  88   }
  89
  90   return TRUE;
  91 }
  92
  93
  94
  95 /**
  96   Verify checksum of the firmware volume header.
  97
  98   @param  FvHeader       Points to the firmware volume header to be checked
  99
 100   @retval TRUE           Checksum verification passed
 101   @retval FALSE          Checksum verification failed
 102
 103 **/
 104 BOOLEAN
 105 VerifyFvHeaderChecksum (
 106   IN EFI_FIRMWARE_VOLUME_HEADER *FvHeader
 107   )
 108 {
 109   UINT32  Index;
 110   UINT32  HeaderLength;
 111   UINT16  Checksum;
 112   UINT16  *Ptr;
 113
 114   HeaderLength = FvHeader->HeaderLength;
 115   Ptr = (UINT16 *)FvHeader;
 116   Checksum = 0;
 117
 118   for (Index = 0; Index < HeaderLength / sizeof (UINT16); Index++) {
 119     Checksum = (UINT16)(Checksum + Ptr[Index]);
 120   }
 121
 122   if (Checksum == 0) {
 123     return TRUE;
 124   } else {
 125     return FALSE;
 126   }
 127 }
 128
 129
 130 /**
 131   Verify checksum of the FFS file header.
 132
 133   @param  FfsHeader      Points to the FFS file header to be checked
 134
 135   @retval TRUE           Checksum verification passed
 136   @retval FALSE          Checksum verification failed
 137
 138 **/
 139 BOOLEAN
 140 VerifyHeaderChecksum (
 141   IN EFI_FFS_FILE_HEADER  *FfsHeader
 142   )
 143 {
 144   UINT32            Index;
 145   UINT8             *Ptr;
 146   UINT8             HeaderChecksum;
 147
 148   Ptr = (UINT8 *)FfsHeader;
 149   HeaderChecksum = 0;
 150   for (Index = 0; Index < sizeof(EFI_FFS_FILE_HEADER); Index++) {
 151     HeaderChecksum = (UINT8)(HeaderChecksum + Ptr[Index]);
 152   }
 153
 154   HeaderChecksum = (UINT8) (HeaderChecksum - FfsHeader->State - FfsHeader->IntegrityCheck.Checksum.File);
 155
 156   if (HeaderChecksum == 0) {
 157     return TRUE;
 158   } else {
 159     return FALSE;
 160   }
 161 }
 162
 163
 164
 165 /**
 166   Check if it's a valid FFS file header.
 167
 168   @param  ErasePolarity  Erase polarity attribute of the firmware volume
 169   @param  FfsHeader      Points to the FFS file header to be checked
 170   @param  FileState      FFS file state to be returned
 171
 172   @retval TRUE           Valid FFS file header
 173   @retval FALSE          Invalid FFS file header
 174
 175 **/
 176 BOOLEAN
 177 IsValidFfsHeader (
 178   IN UINT8                ErasePolarity,
 179   IN EFI_FFS_FILE_HEADER  *FfsHeader,
 180   OUT EFI_FFS_FILE_STATE  *FileState
 181   )
 182 {
 183   *FileState = GetFileState (ErasePolarity, FfsHeader);
 184
 185   switch (*FileState) {
 186     case EFI_FILE_HEADER_VALID:
 187     case EFI_FILE_DATA_VALID:
 188     case EFI_FILE_MARKED_FOR_UPDATE:
 189     case EFI_FILE_DELETED:
 190       //
 191       // Here we need to verify header checksum
 192       //
 193       return VerifyHeaderChecksum (FfsHeader);
 194
 195     case EFI_FILE_HEADER_CONSTRUCTION:
 196     case EFI_FILE_HEADER_INVALID:
 197     default:
 198       return FALSE;
 199   }
 200 }
 201
 202
 203
 204 /**
 205   Check if it's a valid FFS file.
 206   Here we are sure that it has a valid FFS file header since we must call IsValidFfsHeader() first.
 207
 208   @param  ErasePolarity  Erase polarity attribute of the firmware volume
 209   @param  FfsHeader      Points to the FFS file to be checked
 210
 211   @retval TRUE           Valid FFS file
 212   @retval FALSE          Invalid FFS file
 213
 214 **/
 215 BOOLEAN
 216 IsValidFfsFile (
 217   IN UINT8                ErasePolarity,
 218   IN EFI_FFS_FILE_HEADER  *FfsHeader
 219   )
 220 {
 221   EFI_FFS_FILE_STATE  FileState;
 222
 223   FileState = GetFileState (ErasePolarity, FfsHeader);
 224   switch (FileState) {
 225
 226     case EFI_FILE_DELETED:
 227     case EFI_FILE_DATA_VALID:
 228     case EFI_FILE_MARKED_FOR_UPDATE:
 229       //
 230       // Some other vliadation like file content checksum might be done here.
 231       // For performance issue, Tiano only do FileState check.
 232       //
 233       return TRUE;
 234
 235     default:
 236       return FALSE;
 237   }
 238 }
 239
 240