grub_ext2_iterate_dir (grub_fshelp_node_t dir,
		       int (*hook) (const char *filename,
				    enum grub_fshelp_filetype filetype,
				    grub_fshelp_node_t node,
				    void *closure),
		       void *closure)
{
  unsigned int fpos = 0;
  struct grub_fshelp_node *diro = (struct grub_fshelp_node *) dir;

  if (! diro->inode_read)
    {
      grub_ext2_read_inode (diro->data, diro->ino, &diro->inode);
      if (grub_errno)
	return 0;
    }

  /* Search the file.  */
  if (hook)
  while (fpos < grub_le_to_cpu32 (diro->inode.size))
    {
      struct ext2_dirent dirent;

      grub_ext2_read_file (diro, NULL, NULL, 0, fpos, sizeof (dirent),
			   (char *) &dirent);
      if (grub_errno)
	return 0;

      if (dirent.direntlen == 0)
        return 0;

      if (dirent.namelen != 0)
	{
	  char * filename = grub_malloc (dirent.namelen + 1);
	  struct grub_fshelp_node *fdiro;
	  enum grub_fshelp_filetype type = GRUB_FSHELP_UNKNOWN;

if (!filename) {
break;
}
	  grub_ext2_read_file (diro, 0, 0, 0,
			       fpos + sizeof (struct ext2_dirent),
			       dirent.namelen, filename);
	  if (grub_errno) {
            grub_free (filename);
	    return 0;
	  }

	  fdiro = grub_malloc (sizeof (struct grub_fshelp_node));
	  if (! fdiro) {
            grub_free (filename);
	    return 0;
          }

	  fdiro->data = diro->data;
	  fdiro->ino = grub_le_to_cpu32 (dirent.inode);

	  filename[dirent.namelen] = '\0';

	  if (dirent.filetype != FILETYPE_UNKNOWN)
	    {
	      fdiro->inode_read = 0;

	      if (dirent.filetype == FILETYPE_DIRECTORY)
		type = GRUB_FSHELP_DIR;
	      else if (dirent.filetype == FILETYPE_SYMLINK)
		type = GRUB_FSHELP_SYMLINK;
	      else if (dirent.filetype == FILETYPE_REG)
		type = GRUB_FSHELP_REG;
	    }
	  else
	    {
	      /* The filetype can not be read from the dirent, read
		 the inode to get more information.  */
	      grub_ext2_read_inode (diro->data,
                                    grub_le_to_cpu32 (dirent.inode),
				    &fdiro->inode);
	      if (grub_errno) {
                  grub_free (filename);
		  grub_free (fdiro);
		  return 0;
		}

	      fdiro->inode_read = 1;

	      if ((grub_le_to_cpu16 (fdiro->inode.mode)
		   & FILETYPE_INO_MASK) == FILETYPE_INO_DIRECTORY)
		type = GRUB_FSHELP_DIR;
	      else if ((grub_le_to_cpu16 (fdiro->inode.mode)
			& FILETYPE_INO_MASK) == FILETYPE_INO_SYMLINK)
		type = GRUB_FSHELP_SYMLINK;
	      else if ((grub_le_to_cpu16 (fdiro->inode.mode)
			& FILETYPE_INO_MASK) == FILETYPE_INO_REG)
		type = GRUB_FSHELP_REG;
	    }

	  if (hook (filename, type, fdiro, closure)) {
            grub_free (filename);
	    return 1;
          }
          grub_free (filename);
	}

      fpos += grub_le_to_cpu16 (dirent.direntlen);
    }

  return 0;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.