ArmPkg/NorFlashDxe : Fix the check of flash addresses

ronald-cron-arm · oliviermartin · commit ac83357a4311 · 2015-01-23T16:09:07.000Z
Fix the check to prevent any reading past the end of the nor flash. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ronald Cron <ronald.cron@arm.com> Reviewed-by: Olivier Martin <olivier.martin@arm.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16655 6f19259b-4bc3-4df7-8a09-765794883524
diff --git a/ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.c b/ArmPlatformPkg/Drivers/NorFlashDxe/NorFlashDxe.c
@@ -805,8 +805,7 @@ NorFlashRead (
   OUT VOID                *Buffer
   )
 {
-  UINT32              NumBlocks;
-  UINTN               StartAddress;
+  UINTN  StartAddress;
 
   // The buffer must be valid
   if (Buffer == NULL) {
@@ -818,15 +817,7 @@ NorFlashRead (
     return EFI_SUCCESS;
   }
 
-  // All blocks must be within the device
-  NumBlocks = ((UINT32)BufferSizeInBytes) / Instance->Media.BlockSize ;
-
-  if ((Lba + NumBlocks) > (Instance->Media.LastBlock + 1)) {
-    DEBUG ((EFI_D_ERROR, "NorFlashRead: ERROR - Read will exceed last block\n"));
-    return EFI_INVALID_PARAMETER;
-  }
-
-  if (Offset + BufferSizeInBytes >= Instance->Size) {
+  if (((Lba * Instance->Media.BlockSize) + Offset + BufferSizeInBytes) > Instance->Size) {
     DEBUG ((EFI_D_ERROR, "NorFlashRead: ERROR - Read will exceed device size.\n"));
     return EFI_INVALID_PARAMETER;
   }

Original file line number	Diff line number	Diff line change
`@@ -805,8 +805,7 @@ NorFlashRead (`
`805`	`805`	`OUT VOID *Buffer`
`806`	`806`	`)`
`807`	`807`	`{`
`808`		`- UINT32 NumBlocks;`
`809`		`- UINTN StartAddress;`
	`808`	`+ UINTN StartAddress;`
`810`	`809`
`811`	`810`	`// The buffer must be valid`
`812`	`811`	`if (Buffer == NULL) {`
`@@ -818,15 +817,7 @@ NorFlashRead (`
`818`	`817`	`return EFI_SUCCESS;`
`819`	`818`	`}`
`820`	`819`
`821`		`- // All blocks must be within the device`
`822`		`- NumBlocks = ((UINT32)BufferSizeInBytes) / Instance->Media.BlockSize ;`
`823`		`-`
`824`		`- if ((Lba + NumBlocks) > (Instance->Media.LastBlock + 1)) {`
`825`		`- DEBUG ((EFI_D_ERROR, "NorFlashRead: ERROR - Read will exceed last block\n"));`
`826`		`- return EFI_INVALID_PARAMETER;`
`827`		`- }`
`828`		`-`
`829`		`- if (Offset + BufferSizeInBytes >= Instance->Size) {`
	`820`	`+ if (((Lba * Instance->Media.BlockSize) + Offset + BufferSizeInBytes) > Instance->Size) {`
`830`	`821`	`DEBUG ((EFI_D_ERROR, "NorFlashRead: ERROR - Read will exceed device size.\n"));`
`831`	`822`	`return EFI_INVALID_PARAMETER;`
`832`	`823`	`}`