Fix heap-buffer address violation when reading version data from a corrupt binary.

	PR binutils/21437
	* readelf.c (process_version_sections): Check for underflow when
	computing the start address of the auxillary version data.

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 951673b..8bb1fc5 100644 (file)
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,5 +1,11 @@
 2017-04-28  Nick Clifton  <nickc@redhat.com>
 
+       PR binutils/21437
+       * readelf.c (process_version_sections): Check for underflow when
+       computing the start address of the auxillary version data.
+
+2017-04-28  Nick Clifton  <nickc@redhat.com>
+
        PR binutils/21438
        * dwarf.c (process_extended_line_op): Do not assume that the
        string extracted from the section is NUL terminated.

diff --git a/binutils/readelf.c b/binutils/readelf.c
index b57e1e0..72f9dda 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -10178,8 +10178,9 @@ process_version_sections (FILE * file)
                printf (_("  Index: %d  Cnt: %d  "),
                        ent.vd_ndx, ent.vd_cnt);
 
-               /* Check for overflow.  */
-               if (ent.vd_aux + sizeof (* eaux) > (size_t) (endbuf - vstart))
+               /* Check for overflow and underflow.  */
+               if (ent.vd_aux + sizeof (* eaux) > (size_t) (endbuf - vstart)
+                   || (vstart + ent.vd_aux < vstart))
                  break;
 
                vstart += ent.vd_aux;