Date: Wed, 30 Aug 2017 08:15:22 +1000 From: Dave Chinner <david@...morbit.com> To: Kees Cook <keescook@...omium.org> Cc: "Darrick J. Wong" <darrick.wong@...cle.com>, LKML <linux-kernel@...r.kernel.org>, David Windsor <dave@...lcore.net>, linux-xfs@...r.kernel.org, Linux-MM <linux-mm@...ck.org>, "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com> Subject: Re: [PATCH v2 15/30] xfs: Define usercopy region in xfs_inode slab cache 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 > <darrick.wong@...cle.com> 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 > >> <darrick.wong@...cle.com> wrote: > >> > On Mon, Aug 28, 2017 at 02:34:56PM -0700, Kees Cook wrote: > >> >> From: David Windsor <dave@...lcore.net> > >> >> > >> >> 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@...morbit.com
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.