More fixes for memory access violations exposed by fuzzed binaries.

	PR binutils/17512
	* dwarf.h (struct dwarf_section): Add user_data field.
	* dwarf.c (frame_need_space): Check for an over large register
	number.
	(display_debug_frames): Check the return value from
	frame_need_space.  Check for a CFA expression that is so long the
	start address wraps around.
	(debug_displays): Initialise the user_data field.
	* objdump.c (load_specific_debug_section): Save the BFD section
	pointer in the user_data field of the dwarf_section structure.
	(free_debug_section): Update BFD section data when freeing section
	contents.
	* readelf.c (load_specific_debug_section): Initialise the
	user_data field.

	* archive.c (do_slurp_coff_armap): Add range checks to prevent
	running off the end of the string table.
	* compress.c (bfd_get_full_section_contents): Return a NULL
	pointer for zero sized sections.  Do not attempt to copy a buffer
	onto itself.
	* elf-attrs.c (_bfd_elf_parse_attributes): Check for an empty
	header.  Add range checks to avoid running off the end of the
	section.
	* elf.c (bfd_elf_get_str_section): Seek before allocating so that
	if the seek fails, no memory is allocated.
	(bfd_elf_string_from_elf_section): Do not allocate a string from a
	non string section.  It only leads to trouble later on.
	(_bfd_elf_print_private_bfd_data): Check for there being too
	little external dynamic data.
	(bfd_section_from_shdr): Replace assertion with a failure mode.
	(bfd_section_from_shdr): When walking a loaded group section use
	the internal structure size, not the external size.  Check for the
	group section being empty.
	* elf32-i386.c (elf_i386_rtype_to_howto): Replace assertion with a
	failure mode.
	* elfcode.h (elf_slurp_reloc_table): Likewise.
	* reloc.c (bfd_perform_relocation): Avoid seg-fault if the howto
	parameter is NULL.

1 files changed, 3 insertions, 1 deletions

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 5c35d65..dcf37b1 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -379,7 +379,9 @@ elf_i386_rtype_to_howto (bfd *abfd, unsigned r_type)
 			     abfd, (int) r_type);
       indx = R_386_NONE;
     }
-  BFD_ASSERT (elf_howto_table [indx].type == r_type);
+  /* PR 17512: file: 0f67f69d.  */
+  if (elf_howto_table [indx].type != r_type)
+    return NULL;
   return &elf_howto_table[indx];
 }