Re: [PATCH] MdePkg/BasePeCoffLib: skip runtime relocation if relocation info is invalid.

[Laszlo Ersek <lersek@redhat.com>]

On 01/29/19 00:22, Neo Hsueh wrote:
> Skip runtime relocation for PE images that provide invalid relocation infomation
> (ex: RelocDir->Size = 0) to fix a hang observed while booting Windows.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> 
> Signed-off-by: Neo Hsueh <hong-chihx.hsueh@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Dandan Bi <dandan.bi@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> ---
>  MdePkg/Library/BasePeCoffLib/BasePeCoff.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
> index 1bd079ad6a..6d6c37bd61 100644
> --- a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
> +++ b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
> @@ -1002,7 +1002,7 @@ PeCoffLoaderRelocateImage (
>                                                                              RelocDir->VirtualAddress + RelocDir->Size - 1,
>                                                                              TeStrippedOffset
>                                                                              );
> -    if (RelocBase == NULL || RelocBaseEnd == NULL || RelocBaseEnd < RelocBase) {
> +    if (RelocBase == NULL || RelocBaseEnd == NULL || (UINTN) RelocBaseEnd < (UINTN) RelocBase) {
>        ImageContext->ImageError = IMAGE_ERROR_FAILED_RELOCATION;
>        return RETURN_LOAD_ERROR;
>      }
> @@ -1022,7 +1022,7 @@ PeCoffLoaderRelocateImage (
>      // Run the relocation information and apply the fixups
>      //
>      FixupData = ImageContext->FixupData;
> -    while (RelocBase < RelocBaseEnd) {
> +    while ((UINTN) RelocBase < (UINTN) RelocBaseEnd) {
>  
>        Reloc     = (UINT16 *) ((CHAR8 *) RelocBase + sizeof (EFI_IMAGE_BASE_RELOCATION));
>        //
> @@ -1051,7 +1051,7 @@ PeCoffLoaderRelocateImage (
>        //
>        // Run this relocation record
>        //
> -      while (Reloc < RelocEnd) {
> +      while ((UINTN) Reloc < (UINTN) RelocEnd) {
>          Fixup = PeCoffLoaderImageAddress (ImageContext, RelocBase->VirtualAddress + (*Reloc & 0xFFF), TeStrippedOffset);
>          if (Fixup == NULL) {
>            ImageContext->ImageError = IMAGE_ERROR_FAILED_RELOCATION;
> @@ -1746,6 +1746,12 @@ PeCoffLoaderRelocateImageForRuntime (
>                                                                              RelocDir->VirtualAddress + RelocDir->Size - 1,
>                                                                              0
>                                                                              );
> +    if (RelocBase == NULL || RelocBaseEnd == NULL || (UINTN) RelocBaseEnd < (UINTN) RelocBase) {
> +      //
> +      // relocation block is not valid, just return
> +      //
> +      return;
> +    }
>    } else {
>      //
>      // Cannot find relocations, cannot continue to relocate the image, ASSERT for this invalid image.
> @@ -1769,7 +1775,7 @@ PeCoffLoaderRelocateImageForRuntime (
>      //
>      FixupData = RelocationData;
>      RelocBaseOrig = RelocBase;
> -    while (RelocBase < RelocBaseEnd) {
> +    while ((UINTN) RelocBase < (UINTN) RelocBaseEnd) {
>        //
>        // Add check for RelocBase->SizeOfBlock field.
>        //
> @@ -1794,7 +1800,7 @@ PeCoffLoaderRelocateImageForRuntime (
>        //
>        // Run this relocation record
>        //
> -      while (Reloc < RelocEnd) {
> +      while ((UINTN) Reloc < (UINTN) RelocEnd) {
>  
>          Fixup = PeCoffLoaderImageAddress (&ImageContext, RelocBase->VirtualAddress + (*Reloc & 0xFFF), 0);
>          if (Fixup == NULL) {
> 

I think this patch is good enough, but it seems to miss the size==0
check that Dandan asked for.

Thanks,
laszlo