Index: contrib/gcclibs/include/objalloc.h
===================================================================
--- contrib/gcclibs/include/objalloc.h	(revision 284419)
+++ contrib/gcclibs/include/objalloc.h	(working copy)
@@ -1,5 +1,5 @@
 /* objalloc.h -- routines to allocate memory for objects
-   Copyright 1997, 2001 Free Software Foundation, Inc.
+   Copyright 1997, 2001-2012 Free Software Foundation, Inc.
    Written by Ian Lance Taylor, Cygnus Solutions.
 
 This program is free software; you can redistribute it and/or modify it
@@ -91,7 +91,7 @@
      if (__len == 0)							\
        __len = 1;							\
      __len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1);	\
-     (__len <= __o->current_space					\
+     (__len != 0 && __len <= __o->current_space				\
       ? (__o->current_ptr += __len,					\
 	 __o->current_space -= __len,					\
 	 (void *) (__o->current_ptr - __len))				\
Index: contrib/gcclibs/libiberty/objalloc.c
===================================================================
--- contrib/gcclibs/libiberty/objalloc.c	(revision 284419)
+++ contrib/gcclibs/libiberty/objalloc.c	(working copy)
@@ -1,5 +1,5 @@
 /* objalloc.c -- routines to allocate memory for objects
-   Copyright 1997 Free Software Foundation, Inc.
+   Copyright 1997-2012 Free Software Foundation, Inc.
    Written by Ian Lance Taylor, Cygnus Solutions.
 
 This program is free software; you can redistribute it and/or modify it
@@ -112,8 +112,10 @@
 /* Allocate space from an objalloc structure.  */
 
 PTR
-_objalloc_alloc (struct objalloc *o, unsigned long len)
+_objalloc_alloc (struct objalloc *o, unsigned long original_len)
 {
+  unsigned long len = original_len;
+
   /* We avoid confusion from zero sized objects by always allocating
      at least 1 byte.  */
   if (len == 0)
@@ -121,6 +123,11 @@
 
   len = (len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1);
 
+  /* CVE-2012-3509: Check for overflow in the alignment operation above
+   * and then malloc argument below. */
+  if (len + CHUNK_HEADER_SIZE < original_len)
+      return NULL;
+
   if (len <= o->current_space)
     {
       o->current_ptr += len;