x86: Disallow invalid relocation against protected symbol

I am checking this into master and will backport it to 2.38 branch.

H.J
----
On x86, GCC 12 supports -mno-direct-extern-access to enable canonical
reference to protected function and disable copy relocation.  With
-mno-direct-extern-access, the canonical protected function symbols must
be accessed via canonical reference and the protected data symbols in
shared libraries are non-copyable. Under glibc 2.35, non-canonical
reference to the canonical protected function will get the run-time error:

./y: internal_f: ./libfoo.so: non-canonical reference to canonical protected function

and copy relocations against the non-copyable protected symbols will get
the run-time error:

./x: internal_i: ./libfoo.so: copy relocation against non-copyable protected symbol

Update x86 linker to disallow non-canonical reference to the canonical
protected function:

ld: plt.o: non-canonical reference to canonical protected function `internal_f' in libfoo.so
ld: failed to set dynamic section sizes: bad value

and copy relocation against the non-copyable protected symbol:

ld: main.o: copy relocation against non-copyable protected symbol `internal_i' in libfoo.so

at link-time.

bfd/

	PR ld/28875
	* elf-properties.c (_bfd_elf_parse_gnu_properties): Don't skip
	shared libraries for GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS.
	* elf32-i386.c (elf_i386_scan_relocs): Disallow non-canonical
	reference to canonical protected function.
	* elf64-x86-64.c (elf_x86_64_scan_relocs): Likewise.
	* elfxx-x86.c (elf_x86_allocate_dynrelocs): Don't allow copy
	relocation against non-copyable protected symbol.

ld/

	PR ld/28875
	* testsuite/ld-i386/i386.exp: Check non-canonical reference to
	canonical protected function and check copy relocation against
	non-copyable protected symbol.
	* testsuite/ld-i386/pr21997-1.err: New file.
	* testsuite/ld-i386/pr28875.err: Likewise.
	* testsuite/ld-i386/pr28875a.c: Likewise.
	* testsuite/ld-i386/pr28875b.c: Likewise.
	* testsuite/ld-x86-64/pr21997-1a.err: Updated.
	* testsuite/ld-x86-64/pr21997-1b.err: Likewise.
	* testsuite/ld-x86-64/pr28875-data.err: New file.
	* testsuite/ld-x86-64/pr28875-func.err: Likewise.
	* testsuite/ld-x86-64/x86-64.exp: Check non-canonical reference
	to canonical protected function and check copy relocation against
	non-copyable protected symbol.

1 files changed, 17 insertions, 0 deletions

diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 02ca55200bb..b5718e71121 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -2223,6 +2223,23 @@ elf_x86_64_scan_relocs (bfd *abfd, struct bfd_link_info *info,
 		    func_pointer_ref = true;
 		}
 
+	      if (h->pointer_equality_needed
+		  && h->type == STT_FUNC
+		  && eh->def_protected
+		  && elf_has_indirect_extern_access (h->root.u.def.section->owner))
+		{
+		  /* Disallow non-canonical reference to canonical
+		     protected function.  */
+		  _bfd_error_handler
+		    /* xgettext:c-format */
+		    (_("%pB: non-canonical reference to canonical "
+		       "protected function `%s' in %pB"),
+		     abfd, h->root.root.string,
+		     h->root.u.def.section->owner);
+		  bfd_set_error (bfd_error_bad_value);
+		  goto error_return;
+		}
+
 	      if (!func_pointer_ref)
 		{
 		  /* If this reloc is in a read-only section, we might