On 4/18/19 7:47 PM, Laszlo Ersek wrote:
> Accessing "EFI_FFS_FILE_HEADER.Size", which is of type UINT8[3], through a
> (UINT32*), is undefined behavior. Fix it by accessing the array elements
> individually.
>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1710
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
>
> Notes:
> v2:
>
> - eliminate intermediate macros [Mike]
>
> MdePkg/Include/Pi/PiFirmwareFile.h | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/MdePkg/Include/Pi/PiFirmwareFile.h b/MdePkg/Include/Pi/PiFirmwareFile.h
> index 05470538de42..ec7729e9c36e 100644
> --- a/MdePkg/Include/Pi/PiFirmwareFile.h
> +++ b/MdePkg/Include/Pi/PiFirmwareFile.h
> @@ -179,8 +179,15 @@ typedef struct {
> #define IS_FFS_FILE2(FfsFileHeaderPtr) \
> (((((EFI_FFS_FILE_HEADER *) (UINTN) FfsFileHeaderPtr)->Attributes) & FFS_ATTRIB_LARGE_FILE) == FFS_ATTRIB_LARGE_FILE)
>
> -#define FFS_FILE_SIZE(FfsFileHeaderPtr) \
> - ((UINT32) (*((UINT32 *) ((EFI_FFS_FILE_HEADER *) (UINTN) FfsFileHeaderPtr)->Size) & 0x00ffffff))
> +///
> +/// The argument passed as the FfsFileHeaderPtr parameter to the
> +/// FFS_FILE_SIZE() function-like macro below must not have side effects:
> +/// FfsFileHeaderPtr is evaluated multiple times.
> +///
> +#define FFS_FILE_SIZE(FfsFileHeaderPtr) ((UINT32) ( \
> + (((EFI_FFS_FILE_HEADER *) (UINTN) (FfsFileHeaderPtr))->Size[0] ) | \
> + (((EFI_FFS_FILE_HEADER *) (UINTN) (FfsFileHeaderPtr))->Size[1] << 8) | \
> + (((EFI_FFS_FILE_HEADER *) (UINTN) (FfsFileHeaderPtr))->Size[2] << 16)))
>
> #define FFS_FILE2_SIZE(FfsFileHeaderPtr) \
> ((UINT32) (((EFI_FFS_FILE_HEADER2 *) (UINTN) FfsFileHeaderPtr)->ExtendedSize))
>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
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