Fix illegal memory access errors triggered by running srconv on fuzzed binaries.

PR binutils/17512
	* dwarf.c (read_leb128): Fix test for shift becoming too large.

	* coffgrok.c (do_define): Add check for type size overflow.
	* srconv.c (walk_tree_sfile): Check that enough sections are
	available before parsing.
	(prescan): Likewise.

binutils/ChangeLog

@@ -1,3 +1,13 @@
+2015-02-13  Nick Clifton  <nickc@redhat.com>
+
+	PR binutils/17512
+	* dwarf.c (read_leb128): Fix test for shift becoming too large.
+
+	* coffgrok.c (do_define): Add check for type size overflow.
+	* srconv.c (walk_tree_sfile): Check that enough sections are
+	available before parsing.
+	(prescan): Likewise.
+
 2015-02-13  Alan Modra  <amodra@gmail.com>
 
 	* dwarf.c: Formatting, whitespace.

binutils/coffgrok.c

@@ -668,12 +668,10 @@ do_define (unsigned int i, struct coff_scope *b)
 
 	  if (!is->init)
 	    {
-	      long high = s->where->offset + s->type->size; 
-
 	      is->low = s->where->offset;
-	      is->high = high;
+	      is->high = s->where->offset + s->type->size; 
 	      /* PR 17512: file: 37e7a80d.  */
-	      if (is->high != high)
+	      if (is->high < s->where->offset)
 		fatal (_("Out of range type size: %u"), s->type->size);
 	      is->init = 1;
 	      is->parent = s->where->section;

binutils/srconv.c

@@ -1204,6 +1204,8 @@ walk_tree_sfile (struct coff_section *section, struct coff_sfile *sfile)
 static void
 wr_program_structure (struct coff_ofile *p, struct coff_sfile *sfile)
 {
+  if (p->nsections < 4)
+    return;
   walk_tree_sfile (p->sections + 4, sfile);
 }
 
@@ -1705,6 +1707,9 @@ prescan (struct coff_ofile *otree)
   struct coff_symbol *s;
   struct coff_section *common_section;
 
+  if (otree->nsections < 3)
+    return;
+
   /* Find the common section - always section 3.  */
   common_section = otree->sections + 3;
 
@@ -1715,7 +1720,6 @@ prescan (struct coff_ofile *otree)
       if (s->visible->type == coff_vis_common)
 	{
 	  struct coff_where *w = s->where;
-
 	  /*      s->visible->type = coff_vis_ext_def; leave it as common */
 	  common_section->size = align (common_section->size);
 	  w->offset = common_section->size + common_section->address;