From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2120.oracle.com ([156.151.31.85]:34374 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725801AbfC2ECa (ORCPT ); Fri, 29 Mar 2019 00:02:30 -0400 Date: Thu, 28 Mar 2019 21:02:22 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH 3/3] xfs: don't allow most setxattr to immutable files Message-ID: <20190329040222.GC18833@magnolia> References: <155379543409.24796.5783716624820175068.stgit@magnolia> <155379545404.24796.5019142212767521955.stgit@magnolia> <20190328212948.GL23020@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190328212948.GL23020@dastard> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org On Fri, Mar 29, 2019 at 08:29:48AM +1100, Dave Chinner wrote: > On Thu, Mar 28, 2019 at 10:50:54AM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > The chattr manpage has this to say about immutable files: > > > > "A file with the 'i' attribute cannot be modified: it cannot be deleted > > or renamed, no link can be created to this file, most of the file's > > metadata can not be modified, and the file can not be opened in write > > mode." > > > > However, we don't actually check the immutable flag in the setattr code, > > which means that we can update project ids and extent size hints on > > supposedly immutable files. Therefore, reject a setattr call on an > > immutable file except for the case where we're trying to unset > > IMMUTABLE. > > > > Signed-off-by: Darrick J. Wong > > --- > > fs/xfs/xfs_ioctl.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > > index 2bd1c5ab5008..9cf0bc0ae2bd 100644 > > --- a/fs/xfs/xfs_ioctl.c > > +++ b/fs/xfs/xfs_ioctl.c > > @@ -1067,6 +1067,14 @@ xfs_ioctl_setattr_xflags( > > !capable(CAP_LINUX_IMMUTABLE)) > > return -EPERM; > > > > + /* > > + * If immutable is set and we are not clearing it, we're not allowed > > + * to change anything else in the inode. > > + */ > > + if ((ip->i_d.di_flags & XFS_DIFLAG_IMMUTABLE) && > > + (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)) > > + return -EPERM; > > + > > /* diflags2 only valid for v3 inodes. */ > > di_flags2 = xfs_flags2diflags2(ip, fa->fsx_xflags); > > if (di_flags2 && ip->i_d.di_version < 3) > > Looks fine - catches both FS_IOC_SETFLAGS and FS_IOC_FSSETXATTR > for XFS. > > Do the other filesystems that implement FS_IOC_FSSETXATTR have > the same bug? Yes. I'm not even 100% sure I've finished playing xfs whackamole yet. --D > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com