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PATCH: Check number of sections overflow


Hi,

SHN_LORESERVE is defined as

#define SHN_LORESERVE	0xFF00

externally and defined as

#define SHN_LORESERVE	(-0x100u)

internally.  It may overflow when number of sections >= (-0x100u).  It
is very unlikely to happen sine -0x100u is 0xffffff00.  This patch
adds a check just in case.  OK to install?

Thanks.


H.J.
---
2008-03-12  H.J. Lu  <hongjiu.lu@intel.com>

	* elf.c (assign_section_numbers): Check if number of sections
	>= SHN_LORESERVE.
	* elfcode.h (elf_object_p): Likewise.

--- bfd/elf.c.64k	2008-03-12 12:32:53.000000000 -0700
+++ bfd/elf.c	2008-03-12 14:06:17.000000000 -0700
@@ -2831,6 +2831,13 @@ assign_section_numbers (bfd *abfd, struc
       _bfd_elf_strtab_addref (elf_shstrtab (abfd), t->strtab_hdr.sh_name);
     }
 
+  if (section_number >= SHN_LORESERVE)
+    {
+      _bfd_error_handler (_("%B: too many sections: %u"),
+			  abfd, section_number);
+      return FALSE;
+    }
+
   _bfd_elf_strtab_finalize (elf_shstrtab (abfd));
   t->shstrtab_hdr.sh_size = _bfd_elf_strtab_size (elf_shstrtab (abfd));
 
--- bfd/elfcode.h.64k	2008-03-12 12:32:05.000000000 -0700
+++ bfd/elfcode.h	2008-03-12 15:30:51.000000000 -0700
@@ -684,8 +684,14 @@ elf_object_p (bfd *abfd)
       if (i_ehdrp->e_shnum == SHN_UNDEF)
 	{
 	  i_ehdrp->e_shnum = i_shdr.sh_size;
-	  if (i_ehdrp->e_shnum != i_shdr.sh_size
-	      || i_ehdrp->e_shnum == 0)
+	  if (i_ehdrp->e_shnum >= SHN_LORESERVE)
+	    {
+	      _bfd_error_handler (_("%B: too many sections: %u"),
+				  abfd, i_ehdrp->e_shnum);
+	      abort ();
+	    }
+	  else if (i_ehdrp->e_shnum != i_shdr.sh_size
+		   || i_ehdrp->e_shnum  == 0)
 	    goto got_wrong_format_error;
 	}
 


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