* readelf.c (process_version_sections): Fix overflow checks to

	avoid undefined behaviour.

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 7b30f4e..2eedde7 100644 (file)
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,8 @@
+2013-01-29  Xi Wang  <xi.wang@gmail.com>
+
+       * readelf.c (process_version_sections): Fix overflow checks to
+       avoid undefined behaviour.
+
 2013-01-28  Doug Evans  <dje@google.com>
 
        * dwarf.c (display_gdb_index): Handle .gdb_index version 8.

diff --git a/binutils/readelf.c b/binutils/readelf.c
index f880825..ae211a7 100644 (file)
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -1,7 +1,5 @@
 /* readelf.c -- display contents of an ELF format file
-   Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
-   2008, 2009, 2010, 2011, 2012, 2013
-   Free Software Foundation, Inc.
+   Copyright 1998-2013 Free Software Foundation, Inc.
 
    Originally developed by Eric Youngdale <eric@andante.jic.com>
    Modifications by Nick Clifton <nickc@redhat.com>
@@ -8469,8 +8467,8 @@ process_version_sections (FILE * file)
                int j;
                int isum;
 
-               /* Check for negative or very large indicies.  */
-               if ((unsigned char *) edefs + idx < (unsigned char *) edefs)
+               /* Check for very large indicies.  */
+               if (idx > (size_t) (endbuf - (char *) edefs))
                  break;
 
                vstart = ((char *) edefs) + idx;
@@ -8494,8 +8492,7 @@ process_version_sections (FILE * file)
                        ent.vd_ndx, ent.vd_cnt);
 
                /* Check for overflow.  */
-               if ((unsigned char *)(vstart + ent.vd_aux) < (unsigned char *) vstart
-                   || (unsigned char *)(vstart + ent.vd_aux) > (unsigned char *) endbuf)
+               if (ent.vd_aux > (size_t) (endbuf - vstart))
                  break;
 
                vstart += ent.vd_aux;
@@ -8515,8 +8512,7 @@ process_version_sections (FILE * file)
                for (j = 1; j < ent.vd_cnt; j++)
                  {
                    /* Check for overflow.  */
-                   if ((unsigned char *)(vstart + aux.vda_next) < (unsigned char *) vstart
-                       || (unsigned char *)(vstart + aux.vda_next) > (unsigned char *) endbuf)
+                   if (aux.vda_next > (size_t) (endbuf - vstart))
                      break;
 
                    isum   += aux.vda_next;
@@ -8586,7 +8582,7 @@ process_version_sections (FILE * file)
                int isum;
                char * vstart;
 
-               if ((unsigned char *) eneed + idx < (unsigned char *) eneed)
+               if (idx > (size_t) (endbuf - (char *) eneed))
                  break;
 
                vstart = ((char *) eneed) + idx;
@@ -8611,8 +8607,7 @@ process_version_sections (FILE * file)
                printf (_("  Cnt: %d\n"), ent.vn_cnt);
 
                /* Check for overflow.  */
-               if ((unsigned char *)(vstart + ent.vn_aux) < (unsigned char *) vstart
-                   || (unsigned char *)(vstart + ent.vn_aux) > (unsigned char *) endbuf)
+               if (ent.vn_aux > (size_t) (endbuf - vstart))
                  break;
 
                vstart += ent.vn_aux;
@@ -8643,8 +8638,7 @@ process_version_sections (FILE * file)
                            get_ver_flags (aux.vna_flags), aux.vna_other);
 
                    /* Check for overflow.  */
-                   if ((unsigned char *)(vstart + aux.vna_next) < (unsigned char *) vstart
-                       || (unsigned char *)(vstart + aux.vna_next) > (unsigned char *) endbuf)
+                   if (aux.vna_next > (size_t) (endbuf - vstart))
                      break;
 
                    isum   += aux.vna_next;