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From: Edward Adam Davis <eadavis@qq.com>
To: kent.overstreet@linux.dev
Cc: bfoster@redhat.com, eadavis@qq.com,
	linux-bcachefs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	syzbot+c48865e11e7e893ec4ab@syzkaller.appspotmail.com,
	syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] bcachefs: fix oob in bch2_sb_clean_to_text
Date: Wed,  8 May 2024 09:28:47 +0800	[thread overview]
Message-ID: <tencent_B063096003B044521770576F66D1336E2305@qq.com> (raw)
In-Reply-To: <nq3ka3ovvksptfkl5c53c4yn54efhu6dtt356lrda2wg7xzwak@tutbtfe7eskb>

On Tue, 7 May 2024 21:21:16 -0400, Kent Overstreet wrote:
> > > > > diff --git a/fs/bcachefs/sb-clean.c b/fs/bcachefs/sb-clean.c
> > > > > index 35ca3f138de6..194e55b11137 100644
> > > > > --- a/fs/bcachefs/sb-clean.c
> > > > > +++ b/fs/bcachefs/sb-clean.c
> > > > > @@ -278,6 +278,17 @@ static int bch2_sb_clean_validate(struct bch_sb *sb,
> > > > >  		return -BCH_ERR_invalid_sb_clean;
> > > > >  	}
> > > > > 
> > > > > +	for (struct jset_entry *entry = clean->start;
> > > > > +	     entry != vstruct_end(&clean->field);
> > > > > +	     entry = vstruct_next(entry)) {
> > > > > +		if ((void *) vstruct_next(entry) > vstruct_end(&clean->field)) {
> > > > > +			prt_str(err, "entry type ");
> > > > > +			bch2_prt_jset_entry_type(err, le16_to_cpu(entry->type));
> > > > > +			prt_str(err, " overruns end of section");
> > > > > +			return -BCH_ERR_invalid_sb_clean;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > The original judgment here is sufficient, there is no need to add this section of inspection.
> > > 
> > > No, we need to be able to print things that failed to validate so that
> > > we see what went wrong.
> > The follow check work fine, why add above check ?
> >    1         if (vstruct_bytes(&clean->field) < sizeof(*clean)) {
> >   268                 prt_printf(err, "wrong size (got %zu should be %zu)",
> >     1                        vstruct_bytes(&clean->field), sizeof(*clean));
> > 
> 
> You sure you're not inebriated?
Here, is my test log, according to it, I can confirm what went wrong.
[  129.350671][ T7772] bcachefs (/dev/loop0): error validating superblock: Invalid superblock section clean: wrong size (got 8 should be 24)
[  129.350671][ T7772] clean (size 8):
[  129.350671][ T7772] flags:          0
[  129.350671][ T7772] journal_seq:    0


  reply	other threads:[~2024-05-08  1:33 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-05 18:25 [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Read in bch2_sb_clean_to_text syzbot
2024-05-06  4:16 ` syzbot
2024-05-07  9:19 ` [PATCH] bcachefs: fix oob " Edward Adam Davis
2024-05-07 14:14   ` Kent Overstreet
2024-05-08  0:49     ` Edward Adam Davis
2024-05-08  0:59       ` Kent Overstreet
2024-05-08  1:11         ` Edward Adam Davis
2024-05-08  1:21           ` Kent Overstreet
2024-05-08  1:28             ` Edward Adam Davis [this message]
2024-05-07 23:18   ` kernel test robot
2024-05-08  0:13   ` kernel test robot
2024-05-08  1:06   ` kernel test robot

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