Re: [PATCH 6/6] common/populate: add verity files to populate xfs images

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

On Tue, Apr 30, 2024 at 03:22:50PM +0200, Andrey Albershteyn wrote:
> On 2024-04-29 20:42:21, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > If verity is enabled on a filesystem, we should create some sample
> > verity files.
> > 
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> >  common/populate |   24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> > 
> > 
> > diff --git a/common/populate b/common/populate
> > index 35071f4210..ab9495e739 100644
> > --- a/common/populate
> > +++ b/common/populate
> > @@ -520,6 +520,30 @@ _scratch_xfs_populate() {
> >  		done
> >  	fi
> >  
> > +	# verity merkle trees
> > +	is_verity="$(_xfs_has_feature "$SCRATCH_MNT" verity -v)"
> > +	if [ $is_verity -gt 0 ]; then
> > +		echo "+ fsverity"
> > +
> > +		# Create a biggish file with all zeroes, because metadump
> > +		# won't preserve data blocks and we don't want the hashes to
> > +		# stop working for our sample fs.
> 
> Hashes of the data blocks in the merkle tree? All zeros to use
> .zero_digest in fs-verity? Not sure if got this comment right

Oooh, yeah, I need to go check that.  The block elision code might be
neutralizing this.

--D

> > +		for ((pos = 0, i = 88; pos < 23456789; pos += 234567, i++)); do
> > +			$XFS_IO_PROG -f -c "pwrite -S 0 $pos 234567" "$SCRATCH_MNT/verity"
> > +		done
> > +
> > +		fsverity enable "$SCRATCH_MNT/verity"
> > +
> > +		# Create a sparse file
> > +		$XFS_IO_PROG -f -c "pwrite -S 0 0 3" -c "pwrite -S 0 23456789 3" "$SCRATCH_MNT/sparse_verity"
> > +		fsverity enable "$SCRATCH_MNT/sparse_verity"
> > +
> > +		# Create a salted sparse file
> > +		$XFS_IO_PROG -f -c "pwrite -S 0 0 3" -c "pwrite -S 0 23456789 3" "$SCRATCH_MNT/salted_verity"
> > +		local salt="5846532066696e616c6c7920686173206461746120636865636b73756d732121"	# XFS finally has data checksums!!
> > +		fsverity enable --salt="$salt" "$SCRATCH_MNT/salted_verity"
> > +	fi
> > +
> >  	# Copy some real files (xfs tests, I guess...)
> >  	echo "+ real files"
> >  	test $fill -ne 0 && __populate_fill_fs "${SCRATCH_MNT}" 5
> > 
> 
> -- 
> - Andrey
> 
>