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

[Laszlo Ersek <lersek@redhat.com>]

Hi,

I think this is maybe the 3rd or 4th iteration of the patch. That's OK,
but if you don't add v2, v3, v4 identifies to the subject prefix, such
as [PATCH v2], [PATCH v3] etc, then it's too difficult to follow what
one should review vs. what is obsolete.

Anyway, I think this version is good:

On 01/30/19 02:19, 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 | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
> index 1bd079ad6a..e2c62e1932 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;
> @@ -1739,13 +1739,23 @@ PeCoffLoaderRelocateImageForRuntime (
>    // is present in the image. You have to check the NumberOfRvaAndSizes in
>    // the optional header to verify a desired directory entry is there.
>    //
> +  RelocBase = NULL;
> +  RelocBaseEnd = NULL;
>    if (NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC) {
>      RelocDir      = DataDirectory + EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC;
> -    RelocBase     = (EFI_IMAGE_BASE_RELOCATION *) PeCoffLoaderImageAddress (&ImageContext, RelocDir->VirtualAddress, 0);
> -    RelocBaseEnd  = (EFI_IMAGE_BASE_RELOCATION *) PeCoffLoaderImageAddress (&ImageContext,
> -                                                                            RelocDir->VirtualAddress + RelocDir->Size - 1,
> -                                                                            0
> -                                                                            );
> +    if ((RelocDir != NULL) && (RelocDir->Size > 0)) {
> +      RelocBase     = (EFI_IMAGE_BASE_RELOCATION *) PeCoffLoaderImageAddress (&ImageContext, RelocDir->VirtualAddress, 0);
> +      RelocBaseEnd  = (EFI_IMAGE_BASE_RELOCATION *) PeCoffLoaderImageAddress (&ImageContext,
> +                                                                              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 +1779,7 @@ PeCoffLoaderRelocateImageForRuntime (
>      //
>      FixupData = RelocationData;
>      RelocBaseOrig = RelocBase;
> -    while (RelocBase < RelocBaseEnd) {
> +    while ((UINTN) RelocBase < (UINTN) RelocBaseEnd) {
>        //
>        // Add check for RelocBase->SizeOfBlock field.
>        //
> @@ -1794,7 +1804,7 @@ PeCoffLoaderRelocateImageForRuntime (
>        //
>        // Run this relocation record
>        //
> -      while (Reloc < RelocEnd) {
> +      while ((UINTN) Reloc < (UINTN) RelocEnd) {
>  
>          Fixup = PeCoffLoaderImageAddress (&ImageContext, RelocBase->VirtualAddress + (*Reloc & 0xFFF), 0);
>          if (Fixup == NULL) {
> 

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo