On Sun, Jun 03, 2018 at 09:32:21PM -0700, Darrick J. Wong wrote:
> On Mon, Jun 04, 2018 at 10:14:06AM +1000, Dave Chinner wrote:
> > On Sun, Jun 03, 2018 at 04:23:08PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > >
> > > Return -EFSCORRUPTED when the bnobt/cntbt return obviously corrupt
> > > values, rather than letting them bounce around in the internal code.
> > >
> > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > > ---
> > > fs/xfs/libxfs/xfs_alloc.c | 12 ++++++++----
> > > 1 file changed, 8 insertions(+), 4 deletions(-)
> > >
> > >
> > > diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> > > index dc9dd3805d97..0214a77808d0 100644
> > > --- a/fs/xfs/libxfs/xfs_alloc.c
> > > +++ b/fs/xfs/libxfs/xfs_alloc.c
> > > @@ -231,10 +231,14 @@ xfs_alloc_get_rec(
> > > int error;
> > >
> > > error = xfs_btree_get_rec(cur, &rec, stat);
> > > - if (!error && *stat == 1) {
> > > - *bno = be32_to_cpu(rec->alloc.ar_startblock);
> > > - *len = be32_to_cpu(rec->alloc.ar_blockcount);
> > > - }
> > > + if (error || !(*stat))
> > > + return error;
> > > + if (rec->alloc.ar_blockcount == 0)
> > > + return -EFSCORRUPTED;
> > > +
> > > + *bno = be32_to_cpu(rec->alloc.ar_startblock);
> > > + *len = be32_to_cpu(rec->alloc.ar_blockcount);
> >
> > Looks good, but makes me wonder if we should verify that
> > ar_startblock is a valid agbno, and that the extent lies wholly
> > within the AG? That can be another patch, though.
>
> We probably ought to fix all the _get_rec functions to check that
> they're not returning obviously garbage results.
Yup, because that's exactly what the latest fuzzer images are
tripping over - zero'd and/or invalid allocbt records. I'll
make a pass at converting all the _get_rec functions to bounds check
the records they are asked to convert.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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