Re: [committed, PATCH] Check file size before getting section contents

[Alan Modra <amodra at gmail dot com>]

On Mon, Jun 26, 2017 at 04:27:27PM -0700, H.J. Lu wrote:
> On Mon, Jun 26, 2017 at 4:15 PM, Alan Modra <amodra@gmail.com> wrote:
> > On Mon, Jun 26, 2017 at 03:49:12PM -0700, H.J. Lu wrote:
> >>    filesz = bfd_get_file_size (abfd);
> >> +  if (filesz < 0)
> >>      {
> >>        /* This should never happen.  */
> >>        abort ();
> >
> > This will abort for 2G files on some host/target combinations.  Why is
> > that correct?
> >
> 
> That is true.  The problem is
> 
> file_ptr
> bfd_get_size (bfd *abfd)
> {
>   struct stat buf;
> 
>   if (abfd->iovec == NULL)
>     return 0;
> 
>   if (abfd->iovec->bstat (abfd, &buf) != 0)
>     return 0;
> 
>   return buf.st_size;
> }
> 
> Why isn't it "ufile_ptr".

I'm not sure of the history.  However, the question of bfd_get_size
return type being signed isn't that relevant.  What matters more is
the type used in the functions you patched, and that should be
unsigned, and the aborts removed.  Also,
_bfd_generic_get_section_contents_in_window has the same problem that
Pedro fixed for _bfd_generic_get_section_contents.

	PR binutils/21665
	* libbfd.c (_bfd_generic_get_section_contents): Delete abort.
	Use unsigned file pointer type, and remove cast.
	* libbfd.c (_bfd_generic_get_section_contents_in_window): Likewise.
	Add "count", not "sz".

diff --git a/bfd/libbfd.c b/bfd/libbfd.c
index b8c65b5..0776451 100644
--- a/bfd/libbfd.c
+++ b/bfd/libbfd.c
@@ -789,7 +789,7 @@ _bfd_generic_get_section_contents (bfd *abfd,
 				   bfd_size_type count)
 {
   bfd_size_type sz;
-  file_ptr filesz;
+  ufile_ptr filesz;
   if (count == 0)
     return TRUE;
 
@@ -813,14 +813,9 @@ _bfd_generic_get_section_contents (bfd *abfd,
   else
     sz = section->size;
   filesz = bfd_get_file_size (abfd);
-  if (filesz < 0)
-    {
-      /* This should never happen.  */
-      abort ();
-    }
   if (offset + count < count
       || offset + count > sz
-      || (section->filepos + offset + count) > (bfd_size_type) filesz)
+      || section->filepos + offset + count > filesz)
     {
       bfd_set_error (bfd_error_invalid_operation);
       return FALSE;
@@ -843,7 +838,7 @@ _bfd_generic_get_section_contents_in_window
 {
 #ifdef USE_MMAP
   bfd_size_type sz;
-  file_ptr filesz;
+  ufile_ptr filesz;
 
   if (count == 0)
     return TRUE;
@@ -877,13 +872,8 @@ _bfd_generic_get_section_contents_in_window
   else
     sz = section->size;
   filesz = bfd_get_file_size (abfd);
-  if (filesz < 0)
-    {
-      /* This should never happen.  */
-      abort ();
-    }
   if (offset + count > sz
-      || (section->filepos + offset + sz) > (bfd_size_type) filesz
+      || section->filepos + offset + count > filesz
       || ! bfd_get_file_window (abfd, section->filepos + offset, count, w,
 				TRUE))
     return FALSE;

-- 
Alan Modra
Australia Development Lab, IBM