Re: [PATCH] btrfs-progs: print-tree: do sanity checks for dir items

[Josef Bacik <josef@toxicpanda.com>]

On Wed, Jun 05, 2024 at 07:46:49AM +0930, Qu Wenruo wrote:
> 
> 
> 在 2024/6/5 01:28, Josef Bacik 写道:
> > On Tue, Jun 04, 2024 at 02:19:08PM +0930, Qu Wenruo wrote:
> > > There is a bug report that with UBSAN enabled, fuzz/006 test case would
> > > crash.
> > > 
> > > It turns out that the image bko-154021-invalid-drop-level.raw has
> > > invalid dir items, that the name/data len is beyond the item.
> > > 
> > > And if we try to read beyond the eb boundary, UBSAN got triggered.
> > > 
> > > Normally in kernel tree-checker would reject such metadata in the first
> > > place, but in btrfs-progs we can not go that strict or we can not do a
> > > lot of repair.
> > > 
> > > So here just enhance print_dir_item() to do extra sanity checks for
> > > data/name len before reading the contents.
> > > 
> > > Issue: #805
> > > Signed-off-by: Qu Wenruo <wqu@suse.com>
> > 
> > I'd rather not duplicate this check.
> > 
> > Is the print-tree coming from repair?
> 
> Nope, it's "inspect tree-stats" subcommand, it's just really printing
> the root of each tree.
> 
> Remember we still need to call "btrfs ins dump-tree" to analyze fuzzed
> images, if the print-tree is as strict as tree-checker, just image how
> miserable the life would be.
> 

Ugh good point, ok

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef