PATCH: PR ld/11937: ld --build-id crash with non-ELF input

[H.J. Lu]

On Sat, Aug 21, 2010 at 12:08 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Aug 20, 2010 at 9:28 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Aug 20, 2010 at 8:16 AM, Pedro Alves <pedro@codesourcery.com> wrote:
>>> On Friday 20 August 2010 16:00:30, Nick Clifton wrote:
>>>>   Whilst working on another bug I came across a seg-fault in the
>>>>   _after_open() function in elf32.em.  If the target is not an ELF
>>>>   binary then get_elf_backend_data will return NULL, but the code was
>>>>   not checking for this.  Fixed by applying the following patch.
>>>
>>> (...)
>>>
>>>>           bed = get_elf_backend_data (abfd);
>>>> !         if (bed == NULL)
>>>> !           s = NULL;
>>>> !         else
>>>> !           s = bfd_make_section_with_flags (abfd, ".eh_frame_hdr",
>>>> !                                            bed->dynamic_sec_flags
>>>> !                                            | SEC_READONLY);
>>>
>>> Is it valid to call get_elf_backend_data on a non-elf bfd at all?
>>>
>>> #define get_elf_backend_data(abfd) \
>>>   xvec_get_elf_backend_data ((abfd)->xvec)
>>>
>>> #define bfd_mach_o_get_backend_data(abfd) \
>>>  ((bfd_mach_o_backend_data*)(abfd)->xvec->backend_data)
>>>
>>> .#define coff_backend_info(abfd) \
>>> .  ((bfd_coff_backend_data *) (abfd)->xvec->backend_data)
>>>
>>> It appears that for other flavours, it may happen to return
>>> something undefined.
>>>
>>> Shouldn't that check be something like
>>> bfd_get_flavour (abfd) != bfd_target_elf_flavour instead?
>>>
>>
>> I agree. The patch doesn't look right to me. Nick, if you can
>> provide a testcase, I will look into it.
>>
>
> I opened a bug report:
>
> http://sourceware.org/bugzilla/show_bug.cgi?id=11937
>

Here is a patch.  OK to install?

-- 
H.J.
---
2010-08-21  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11937
	* emultempl/elf32.em (_after_open): Find an ELF input for
	--build-id and --eh-frame-hdr.
-------------- next part --------------
2010-08-21  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11937
	* emultempl/elf32.em (_after_open): Find an ELF input for
	--build-id and --eh-frame-hdr.

diff --git a/ld/emultempl/elf32.em b/ld/emultempl/elf32.em
index 2decd18..bf4359d 100644
--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@@ -1065,7 +1065,11 @@ gld${EMULATION_NAME}_after_open (void)
       asection *s;
       bfd_size_type size;
 
-      abfd = link_info.input_bfds;
+      /* Find an ELF input.  */
+      for (abfd = link_info.input_bfds;
+	   abfd != (bfd *) NULL; abfd = abfd->link_next)
+	if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+	  break;
 
       if (abfd == NULL)
 	{
@@ -1120,33 +1124,38 @@ gld${EMULATION_NAME}_after_open (void)
   if (link_info.eh_frame_hdr
       && !link_info.traditional_format)
     {
-      bfd *abfd;
+      bfd *abfd, *elfbfd = NULL;
+      bfd_boolean warn_eh_frame = FALSE;
       asection *s;
 
       for (abfd = link_info.input_bfds; abfd; abfd = abfd->link_next)
 	{
+	  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+	    elfbfd = abfd;
 	  s = bfd_get_section_by_name (abfd, ".eh_frame");
-	  if (s && s->size > 8 && !bfd_is_abs_section (s->output_section))
-	    break;
+	   if (s && s->size > 8 && !bfd_is_abs_section (s->output_section))
+	     warn_eh_frame = TRUE;
+	   if (elfbfd && warn_eh_frame)
+	     break;
 	}
-      if (abfd)
+      if (elfbfd)
 	{
 	  const struct elf_backend_data *bed;
 
-	  bed = get_elf_backend_data (abfd);
-	  if (bed == NULL)
-	    s = NULL;
-	  else
-	    s = bfd_make_section_with_flags (abfd, ".eh_frame_hdr",
-					     bed->dynamic_sec_flags
-					     | SEC_READONLY);
+	  bed = get_elf_backend_data (elfbfd);
+	  s = bfd_make_section_with_flags (elfbfd, ".eh_frame_hdr",
+					   bed->dynamic_sec_flags
+					   | SEC_READONLY);
 	  if (s != NULL
-	      && bfd_set_section_alignment (abfd, s, 2))
-	    htab->eh_info.hdr_sec = s;
-	  else
-	    einfo ("%P: warning: Cannot create .eh_frame_hdr section,"
-		   " --eh-frame-hdr ignored.\n");
+	      && bfd_set_section_alignment (elfbfd, s, 2))
+	    {
+	      htab->eh_info.hdr_sec = s;
+	      warn_eh_frame = FALSE;
+	    }
 	}
+      if (warn_eh_frame)
+	einfo ("%P: warning: Cannot create .eh_frame_hdr section,"
+	       " --eh-frame-hdr ignored.\n");
     }
 
   /* Get the list of files which appear in DT_NEEDED entries in