Re: [PATCH v5 05/24] fs: add FS_XFLAG_VERITY for verity files

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Mar 04, 2024 at 02:35:48PM -0800, Eric Biggers wrote:
> On Mon, Mar 04, 2024 at 08:10:28PM +0100, Andrey Albershteyn wrote:
> > @@ -641,6 +645,13 @@ static int fileattr_set_prepare(struct inode *inode,
> >  	    !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
> >  		return -EINVAL;
> >  
> > +	/*
> > +	 * Verity cannot be set through FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS.
> > +	 * See FS_IOC_ENABLE_VERITY
> > +	 */
> > +	if (fa->fsx_xflags & FS_XFLAG_VERITY)
> > +		return -EINVAL;
> 
> This makes FS_IOC_SETFLAGS and FS_IOC_FSSETXATTR start failing on files that
> already have verity enabled.
> 
> An error should only be returned when the new flags contain verity and the old
> flags don't.

What if the old flags have it and the new ones don't?  Is that supposed
to disable fsverity?  Is removal of the verity information not supported?

I'm guessing that removal isn't supposed to happen, in which case the
above check ought to be:

	if (!!IS_VERITY(inode) != !!(fa->fsx_xflags & FS_XFLAG_VERITY))
		return -EINVAL;

Right?

--D

> - Eric
>