libiberty: prevent integer overflow.

Take care of very old bug leading to heap-buffer overflow by
processing certain file headers via bfd binary.

PR:		200888
Obtained from:	OpenBSD
MFC after:	2 weeks

1 files changed, 9 insertions, 2 deletions

diff --git a/contrib/gcclibs/libiberty/objalloc.c b/contrib/gcclibs/libiberty/objalloc.c
index 3ddac2c..394b3af 100644
--- a/contrib/gcclibs/libiberty/objalloc.c
+++ b/contrib/gcclibs/libiberty/objalloc.c
@@ -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 @@ objalloc_create (void)
 /* 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 @@ _objalloc_alloc (struct objalloc *o, unsigned long len)
 
   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;