Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751840AbdH2WP1 (ORCPT ); Tue, 29 Aug 2017 18:15:27 -0400 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:62415 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310AbdH2WP0 (ORCPT ); Tue, 29 Aug 2017 18:15:26 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2D4AQCv5qVZ//yBpzteGgEBAQECAQEBAQgBAQEBhD6BFY8Jj2gGgSqNGIshKIUZAgIBAQKEbAECAQEBAQECayiFGAEBAQEDJxMcIxAIAxUDCSUPBSUDIROKJAwRsFE6i0gBAQEBAQEBAwEBAQEBHgUggwqDCYIqgyiDAIU4gjEFoGiHWYxmgh+JZIZ1SJV6V4ENMiEIHBVJgluEUi42i1IBAQE Date: Wed, 30 Aug 2017 08:15:22 +1000 From: Dave Chinner To: Kees Cook Cc: "Darrick J. Wong" , LKML , David Windsor , linux-xfs@vger.kernel.org, Linux-MM , "kernel-hardening@lists.openwall.com" Subject: Re: [PATCH v2 15/30] xfs: Define usercopy region in xfs_inode slab cache Message-ID: <20170829221522.GE10621@dastard> References: <1503956111-36652-1-git-send-email-keescook@chromium.org> <1503956111-36652-16-git-send-email-keescook@chromium.org> <20170828214957.GJ4757@magnolia> <20170829044707.GP4757@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2510 Lines: 58 On Tue, Aug 29, 2017 at 11:48:49AM -0700, Kees Cook wrote: > On Mon, Aug 28, 2017 at 9:47 PM, Darrick J. Wong > wrote: > > On Mon, Aug 28, 2017 at 02:57:14PM -0700, Kees Cook wrote: > >> On Mon, Aug 28, 2017 at 2:49 PM, Darrick J. Wong > >> wrote: > >> > On Mon, Aug 28, 2017 at 02:34:56PM -0700, Kees Cook wrote: > >> >> From: David Windsor > >> >> > >> >> The XFS inline inode data, stored in struct xfs_inode_t field > >> >> i_df.if_u2.if_inline_data and therefore contained in the xfs_inode slab > >> >> cache, needs to be copied to/from userspace. > >> >> > >> >> cache object allocation: > >> >> fs/xfs/xfs_icache.c: > >> >> xfs_inode_alloc(...): > >> >> ... > >> >> ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP); > >> >> > >> >> fs/xfs/libxfs/xfs_inode_fork.c: > >> >> xfs_init_local_fork(...): > >> >> ... > >> >> if (mem_size <= sizeof(ifp->if_u2.if_inline_data)) > >> >> ifp->if_u1.if_data = ifp->if_u2.if_inline_data; > >> > > >> > Hmm, what happens when mem_size > sizeof(if_inline_data)? A slab object > >> > will be allocated for ifp->if_u1.if_data which can then be used for > >> > readlink in the same manner as the example usage trace below. Does > >> > that allocated object have a need for a usercopy annotation like > >> > the one we're adding for if_inline_data? Or is that already covered > >> > elsewhere? > >> > >> Yeah, the xfs helper kmem_alloc() is used in the other case, which > >> ultimately boils down to a call to kmalloc(), which is entirely > >> whitelisted by an earlier patch in the series: > >> > >> https://lkml.org/lkml/2017/8/28/1026 > > > > Ah. It would've been helpful to have the first three patches cc'd to > > the xfs list. So basically this series establishes the ability to set > > I went back and forth on that, and given all the things it touched, it > seemed like too large a CC list. :) I can explicitly add the xfs list > to the first three for any future versions. If you are touching multiple filesystems, you really should cc the entire patchset to linux-fsdevel, similar to how you sent the entire patchset to lkml. That way the entire series will end up on a list that almost all fs developers read. LKML is not a list you can rely on all filesystem developers reading (or developers in any other subsystem, for that matter)... Cheers, Dave. -- Dave Chinner david@fromorbit.com