[PATCH 1/2] x86: Add GNU_PROPERTY_X86_UINT32_VALID

[H.J. Lu]

The older linker treats .note.gnu.property section as a generic note
and just concatenates all .note.gnu.property sections from the input
to the output.  On CET-enabled OS, the output of the older linker is
marked as CET enabled, but in fact, it is not CET enabled and it crashes
on CET-enabled machines.

This patch defines GNU_PROPERTY_X86_UINT32_VALID.  Linker is updated to
set the GNU_PROPERTY_X86_UINT32_VALID bit in GNU property note for
non-relocatable output to differentiate outputs from the older linker.

bfd/

	* elfxx-x86.c (_bfd_x86_elf_parse_gnu_properties): Mask out the
	GNU_PROPERTY_X86_UINT32_VALID bit.
	(_bfd_x86_elf_link_fixup_gnu_properties): Set the
	GNU_PROPERTY_X86_UINT32_VALID bit for non-relocatable output.

binutils/

	* readelf.c (print_gnu_property_note): Check the
	GNU_PROPERTY_X86_UINT32_VALID bit for invalid GNU property note.

include/

	* elf/common.h (GNU_PROPERTY_X86_UINT32_VALID): New.
---
 bfd/elfxx-x86.c      | 17 ++++++++++++-----
 binutils/readelf.c   | 44 +++++++++++++++++++++++++++++++++++---------
 include/elf/common.h |  3 +++
 3 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index 1a4c723969..0d91e4dfc9 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -2378,8 +2378,10 @@ _bfd_x86_elf_parse_gnu_properties (bfd *abfd, unsigned int type,
 	  return property_corrupt;
 	}
       prop = _bfd_elf_get_property (abfd, type, datasz);
-      /* Combine properties of the same type.  */
-      prop->u.number |= bfd_h_get_32 (abfd, ptr);
+      /* Mask out GNU_PROPERTY_X86_UINT32_VALID and combine properties
+	 of the same type.  */
+      prop->u.number |= (bfd_h_get_32 (abfd, ptr)
+			 & ~GNU_PROPERTY_X86_UINT32_VALID);
       prop->pr_kind = property_number;
       break;
 
@@ -2963,9 +2965,8 @@ error_alignment:
 /* Fix up x86 GNU properties.  */
 
 void
-_bfd_x86_elf_link_fixup_gnu_properties
-  (struct bfd_link_info *info ATTRIBUTE_UNUSED,
-   elf_property_list **listp)
+_bfd_x86_elf_link_fixup_gnu_properties (struct bfd_link_info *info,
+					elf_property_list **listp)
 {
   elf_property_list *p;
 
@@ -2981,6 +2982,12 @@ _bfd_x86_elf_link_fixup_gnu_properties
 	    *listp = p->next;
 	    continue;
 	  }
+
+	/* Mark x86-specific properties with X86_UINT32_VALID for
+	   non-relocatable output.  */
+	if (!(bfd_link_relocatable (info)))
+	  p->property.u.number |= GNU_PROPERTY_X86_UINT32_VALID;
+
 	listp = &p->next;
 	break;
       default:
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 8a61db6459..0d0f962c3d 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -17050,30 +17050,56 @@ print_gnu_property_note (Filedata * filedata, Elf_Internal_Note * pnote)
 	      || filedata->file_header.e_machine == EM_IAMCU
 	      || filedata->file_header.e_machine == EM_386)
 	    {
+	      unsigned int bitmask;
+
+	      if (datasz == 4)
+		{
+		  bitmask = byte_get (ptr, 4);
+		  if (filedata->file_header.e_type == ET_EXEC
+		      || filedata->file_header.e_type == ET_DYN)
+		    {
+		      if ((bitmask & GNU_PROPERTY_X86_UINT32_VALID))
+			bitmask &= ~GNU_PROPERTY_X86_UINT32_VALID;
+		      else
+			printf ("Invalid ");
+		    }
+		}
+	      else
+		bitmask = 0;
+
 	      switch (type)
 		{
 		case GNU_PROPERTY_X86_ISA_1_USED:
-		  printf ("x86 ISA used: ");
 		  if (datasz != 4)
-		    printf (_("<corrupt length: %#x> "), datasz);
+		    printf (_("x86 ISA used: <corrupt length: %#x> "),
+			    datasz);
 		  else
-		    decode_x86_isa (byte_get (ptr, 4));
+		    {
+		      printf ("x86 ISA used: ");
+		      decode_x86_isa (bitmask);
+		    }
 		  goto next;
 
 		case GNU_PROPERTY_X86_ISA_1_NEEDED:
-		  printf ("x86 ISA needed: ");
 		  if (datasz != 4)
-		    printf (_("<corrupt length: %#x> "), datasz);
+		    printf (_("x86 ISA needed: <corrupt length: %#x> "),
+			    datasz);
 		  else
-		    decode_x86_isa (byte_get (ptr, 4));
+		    {
+		      printf ("x86 ISA needed: ");
+		      decode_x86_isa (bitmask);
+		    }
 		  goto next;
 
 		case GNU_PROPERTY_X86_FEATURE_1_AND:
-		  printf ("x86 feature: ");
 		  if (datasz != 4)
-		    printf (_("<corrupt length: %#x> "), datasz);
+		    printf (_("x86 feature: <corrupt length: %#x> "),
+			    datasz);
 		  else
-		    decode_x86_feature (type, byte_get (ptr, 4));
+		    {
+		      printf ("x86 feature: ");
+		      decode_x86_feature (type, bitmask);
+		    }
 		  goto next;
 
 		default:
diff --git a/include/elf/common.h b/include/elf/common.h
index 1a940ff7b5..55c5505bac 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -752,6 +752,9 @@
 #define GNU_PROPERTY_X86_ISA_1_NEEDED		0xc0000001
 #define GNU_PROPERTY_X86_FEATURE_1_AND		0xc0000002
 
+/* Set by linker to indicate that the property is valid.  */
+#define GNU_PROPERTY_X86_UINT32_VALID		(1U << 31)
+
 #define GNU_PROPERTY_X86_ISA_1_486           (1U << 0)
 #define GNU_PROPERTY_X86_ISA_1_586           (1U << 1)
 #define GNU_PROPERTY_X86_ISA_1_686           (1U << 2)
-- 
2.17.1