Improves the detection of partial .debug_line sections.

	* dwarf.c (read_debug_line_header): Use reloc_at to detect
	incomplete .debug_line headers

2 files changed, 15 insertions, 8 deletions

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 03eb240..63fefc8 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,8 @@
+2015-06-05  Nick Clifton  <nickc@redhat.com>
+
+	* dwarf.c (read_debug_line_header): Use reloc_at to detect
+	incomplete .debug_line headers
+
 2015-05-29  Roland McGrath  <mcgrathr@google.com>
 
 	* readelf.c (print_gnu_note: NT_GNU_ABI_TAG): Recognize
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index 71b0e97..c3dc814 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -2761,18 +2761,20 @@ read_debug_line_header (struct dwarf_section * section,
 
   if (linfo->li_length + initial_length_size > section->size)
     {
-      /* If the length is just a bias against the initial_length_size then
-	 this means that the field has a relocation against it which has not
-	 been applied.  (Ie we are dealing with an object file, not a linked
-	 binary).  Do not complain but instead assume that the rest of the
-	 section applies to this particular header.  */
-      if (linfo->li_length == - initial_length_size)
+      /* If the length field has a relocation against it, then we should
+	 not complain if it is inaccurate (and probably negative).  This
+	 happens in object files when the .debug_line section is actually
+	 comprised of several different .debug_line.* sections, (some of
+	 which may be removed by linker garbage collection), and a relocation
+	 is used to compute the correct length once that is done.  */
+      if (reloc_at (section, (hdrptr - section->start) - offset_size))
 	{
-	  linfo->li_length = section->size - initial_length_size;
+	  linfo->li_length = (end - data) - initial_length_size;
 	}
       else
 	{
-	  warn (_("The line info appears to be corrupt - the section is too small\n"));
+	  warn (_("The length field (0x%lx) in the debug_line header is wrong - the section is too small\n"),
+		(long) linfo->li_length);
 	  return NULL;
 	}
     }