Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753253Ab3GIUxX (ORCPT ); Tue, 9 Jul 2013 16:53:23 -0400 Received: from relay1.sgi.com ([192.48.179.29]:49746 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751945Ab3GIUxW (ORCPT ); Tue, 9 Jul 2013 16:53:22 -0400 Date: Tue, 9 Jul 2013 15:53:21 -0500 From: Ben Myers To: Yann Droneaud Cc: linux-kernel@vger.kernel.org, xfs@oss.sgi.com Subject: Re: [PATCH 10/13] xfs: use get_unused_fd_flags(0) instead of get_unused_fd() Message-ID: <20130709205321.GV20932@sgi.com> References: <8d21b76c621dbfc59b2dbbfc933f96170835304d.1372777600.git.ydroneaud@opteya.com> <20130708224133.GA23250@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130708224133.GA23250@sgi.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2052 Lines: 56 Yann, On Mon, Jul 08, 2013 at 05:41:33PM -0500, Ben Myers wrote: > On Tue, Jul 02, 2013 at 06:39:34PM +0200, Yann Droneaud wrote: > > Macro get_unused_fd() is used to allocate a file descriptor with > > default flags. Those default flags (0) can be "unsafe": > > O_CLOEXEC must be used by default to not leak file descriptor > > across exec(). > > > > Instead of macro get_unused_fd(), functions anon_inode_getfd() > > or get_unused_fd_flags() should be used with flags given by userspace. > > If not possible, flags should be set to O_CLOEXEC to provide userspace > > with a default safe behavor. > > > > In a further patch, get_unused_fd() will be removed so that > > new code start using anon_inode_getfd() or get_unused_fd_flags() > > with correct flags. > > > > This patch replaces calls to get_unused_fd() with equivalent call to > > get_unused_fd_flags(0) to preserve current behavor for existing code. > > > > The hard coded flag value (0) should be reviewed on a per-subsystem basis, > > and, if possible, set to O_CLOEXEC. > > > > Signed-off-by: Yann Droneaud > > > > --- > > fs/xfs/xfs_ioctl.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > > index 5e99968..dc5b659 100644 > > --- a/fs/xfs/xfs_ioctl.c > > +++ b/fs/xfs/xfs_ioctl.c > > @@ -248,7 +248,7 @@ xfs_open_by_handle( > > goto out_dput; > > } > > > > - fd = get_unused_fd(); > > + fd = get_unused_fd_flags(0); > > O_CLOEXEC should be fine in this case. > > Reviewed-by: Ben Myers Applied at git://oss.sgi.com/xfs/xfs.git. Looks like I was wrong about O_CLOEXEC being ok here. There may be applications which open_by_handle then fork/exec and expect to still be able to use that file descriptor. Thanks, Ben -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/