[PATCH v3 3/4] MdePkg/PeCoffLib: Capture DLL characteristics fields in image context

["Ard Biesheuvel" <ardb@kernel.org>]

When loading a PE/COFF image, capture the DLL characteristics fields of
the header into our image context structure so we can refer to them when
mapping the image.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
---
 MdePkg/Include/IndustryStandard/PeImage.h | 13 +++++-
 MdePkg/Include/Library/PeCoffLib.h        |  6 +++
 MdePkg/Library/BasePeCoffLib/BasePeCoff.c | 46 +++++++++++++++-----
 3 files changed, 53 insertions(+), 12 deletions(-)

diff --git a/MdePkg/Include/IndustryStandard/PeImage.h b/MdePkg/Include/IndustryStandard/PeImage.h
index dd4cc25483bc4bcf..8646ff22b55faff0 100644
--- a/MdePkg/Include/IndustryStandard/PeImage.h
+++ b/MdePkg/Include/IndustryStandard/PeImage.h
@@ -625,7 +625,8 @@ typedef struct {
   UINT32    FileOffset;  ///< The file pointer to the debug data.
 } EFI_IMAGE_DEBUG_DIRECTORY_ENTRY;
 
-#define EFI_IMAGE_DEBUG_TYPE_CODEVIEW  2    ///< The Visual C++ debug information.
+#define EFI_IMAGE_DEBUG_TYPE_CODEVIEW               2    ///< The Visual C++ debug information.
+#define EFI_IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS  20
 
 ///
 /// Debug Data Structure defined in Microsoft C++.
@@ -669,6 +670,16 @@ typedef struct {
   //
 } EFI_IMAGE_DEBUG_CODEVIEW_MTOC_ENTRY;
 
+///
+/// Extended DLL Characteristics
+///
+#define EFI_IMAGE_DLLCHARACTERISTICS_EX_CET_COMPAT          0x0001
+#define EFI_IMAGE_DLLCHARACTERISTICS_EX_FORWARD_CFI_COMPAT  0x0040
+
+typedef struct {
+  UINT32    DllCharacteristicsEx;
+} EFI_IMAGE_DEBUG_EX_DLLCHARACTERISTICS_ENTRY;
+
 ///
 /// Resource format.
 ///
diff --git a/MdePkg/Include/Library/PeCoffLib.h b/MdePkg/Include/Library/PeCoffLib.h
index b45879453785c77d..74cceb37bf39ffc6 100644
--- a/MdePkg/Include/Library/PeCoffLib.h
+++ b/MdePkg/Include/Library/PeCoffLib.h
@@ -171,6 +171,12 @@ typedef struct {
   ///
   UINT16                      ImageType;
   ///
+  /// Set by PeCoffLoaderGetImageInfo() to the DLL flags stored in the PE/COFF header and
+  /// in the DllCharacteristicsEx debug table.
+  ///
+  UINT16                      DllCharacteristics;
+  UINT32                      DllCharacteristicsEx;
+  ///
   /// Set by PeCoffLoaderGetImageInfo() to TRUE if the PE/COFF image does not contain
   /// relocation information.
   ///
diff --git a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
index 97a8aaf8c73d3e3c..4b71176a0c7c2ed0 100644
--- a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
+++ b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
@@ -308,10 +308,11 @@ PeCoffLoaderGetPeHeader (
       //
       // Use PE32 offset
       //
-      ImageContext->ImageType        = Hdr.Pe32->OptionalHeader.Subsystem;
-      ImageContext->ImageSize        = (UINT64)Hdr.Pe32->OptionalHeader.SizeOfImage;
-      ImageContext->SectionAlignment = Hdr.Pe32->OptionalHeader.SectionAlignment;
-      ImageContext->SizeOfHeaders    = Hdr.Pe32->OptionalHeader.SizeOfHeaders;
+      ImageContext->ImageType          = Hdr.Pe32->OptionalHeader.Subsystem;
+      ImageContext->ImageSize          = (UINT64)Hdr.Pe32->OptionalHeader.SizeOfImage;
+      ImageContext->SectionAlignment   = Hdr.Pe32->OptionalHeader.SectionAlignment;
+      ImageContext->SizeOfHeaders      = Hdr.Pe32->OptionalHeader.SizeOfHeaders;
+      ImageContext->DllCharacteristics = Hdr.Pe32->OptionalHeader.DllCharacteristics;
     } else if (Hdr.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
       //
       // 1. Check FileHeader.NumberOfRvaAndSizes filed.
@@ -429,10 +430,11 @@ PeCoffLoaderGetPeHeader (
       //
       // Use PE32+ offset
       //
-      ImageContext->ImageType        = Hdr.Pe32Plus->OptionalHeader.Subsystem;
-      ImageContext->ImageSize        = (UINT64)Hdr.Pe32Plus->OptionalHeader.SizeOfImage;
-      ImageContext->SectionAlignment = Hdr.Pe32Plus->OptionalHeader.SectionAlignment;
-      ImageContext->SizeOfHeaders    = Hdr.Pe32Plus->OptionalHeader.SizeOfHeaders;
+      ImageContext->ImageType          = Hdr.Pe32Plus->OptionalHeader.Subsystem;
+      ImageContext->ImageSize          = (UINT64)Hdr.Pe32Plus->OptionalHeader.SizeOfImage;
+      ImageContext->SectionAlignment   = Hdr.Pe32Plus->OptionalHeader.SectionAlignment;
+      ImageContext->SizeOfHeaders      = Hdr.Pe32Plus->OptionalHeader.SizeOfHeaders;
+      ImageContext->DllCharacteristics = Hdr.Pe32Plus->OptionalHeader.DllCharacteristics;
     } else {
       ImageContext->ImageError = IMAGE_ERROR_INVALID_MACHINE_TYPE;
       return RETURN_UNSUPPORTED;
@@ -545,8 +547,9 @@ PeCoffLoaderGetPeHeader (
   Retrieves information about a PE/COFF image.
 
   Computes the PeCoffHeaderOffset, IsTeImage, ImageType, ImageAddress, ImageSize,
-  DestinationAddress, RelocationsStripped, SectionAlignment, SizeOfHeaders, and
-  DebugDirectoryEntryRva fields of the ImageContext structure.
+  DestinationAddress, RelocationsStripped, SectionAlignment, SizeOfHeaders,
+  DllCharacteristics, DllCharacteristicsEx and DebugDirectoryEntryRva fields of
+  the ImageContext structure.
   If ImageContext is NULL, then return RETURN_INVALID_PARAMETER.
   If the PE/COFF image accessed through the ImageRead service in the ImageContext
   structure is not a supported PE/COFF image type, then return RETURN_UNSUPPORTED.
@@ -752,7 +755,28 @@ PeCoffLoaderGetImageInfo (
               ImageContext->ImageSize += DebugEntry.SizeOfData;
             }
 
-            return RETURN_SUCCESS;
+            continue;
+          }
+
+          if (DebugEntry.Type == EFI_IMAGE_DEBUG_TYPE_EX_DLLCHARACTERISTICS) {
+            Size     = sizeof (EFI_IMAGE_DEBUG_EX_DLLCHARACTERISTICS_ENTRY);
+            ReadSize = sizeof (EFI_IMAGE_DEBUG_EX_DLLCHARACTERISTICS_ENTRY);
+            Status   = ImageContext->ImageRead (
+                                       ImageContext->Handle,
+                                       DebugEntry.FileOffset,
+                                       &Size,
+                                       &ImageContext->DllCharacteristicsEx
+                                       );
+            if (RETURN_ERROR (Status) || (Size != ReadSize)) {
+              ImageContext->ImageError = IMAGE_ERROR_IMAGE_READ;
+              if (Size != ReadSize) {
+                Status = RETURN_UNSUPPORTED;
+              }
+
+              return Status;
+            }
+
+            continue;
           }
         }
       }
-- 
2.39.2