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 <darrick.wong@xxxxxxxxxx> > > > > 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 <darrick.wong@xxxxxxxxxx> > > --- > > 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@xxxxxxxxxxxxx
