From: Jan Kara <jack@suse.cz>
To: Pavel Skripkin <paskripkin@gmail.com>
Cc: jack@suse.cz, tiantao6@hisilicon.com, rdunlap@infradead.org,
reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com
Subject: Re: [PATCH v2] reiserfs: add check for invalid 1st journal block
Date: Mon, 17 May 2021 15:08:18 +0200 [thread overview]
Message-ID: <20210517130818.GB25760@quack2.suse.cz> (raw)
In-Reply-To: <20210517121545.29645-1-paskripkin@gmail.com>
On Mon 17-05-21 15:15:45, Pavel Skripkin wrote:
> syzbot reported divide error in reiserfs.
> The problem was in incorrect journal 1st block.
>
> Syzbot's reproducer manualy generated wrong superblock
> with incorrect 1st block. In journal_init() wasn't
> any checks about this particular case.
>
> For example, if 1st journal block is before superblock
> 1st block, it can cause zeroing important superblock members
> in do_journal_end().
>
> Reported-by: syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Thanks! I've added the patch to my tree.
Honza
> ---
>
> Changes in v2:
> Added necessary !SB_ONDISK_JOURNAL_DEVICE(sb) in "if"
>
> ---
> fs/reiserfs/journal.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
> index 9edc8e2b154e..0834b101c316 100644
> --- a/fs/reiserfs/journal.c
> +++ b/fs/reiserfs/journal.c
> @@ -2758,6 +2758,20 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
> goto free_and_return;
> }
>
> + /*
> + * Sanity check to see if journal first block is correct.
> + * If journal first block is invalid it can cause
> + * zeroing important superblock members.
> + */
> + if (!SB_ONDISK_JOURNAL_DEVICE(sb) &&
> + SB_ONDISK_JOURNAL_1st_BLOCK(sb) < SB_JOURNAL_1st_RESERVED_BLOCK(sb)) {
> + reiserfs_warning(sb, "journal-1393",
> + "journal 1st super block is invalid: 1st reserved block %d, but actual 1st block is %d",
> + SB_JOURNAL_1st_RESERVED_BLOCK(sb),
> + SB_ONDISK_JOURNAL_1st_BLOCK(sb));
> + goto free_and_return;
> + }
> +
> if (journal_init_dev(sb, journal, j_dev_name) != 0) {
> reiserfs_warning(sb, "sh-462",
> "unable to initialize journal device");
> --
> 2.31.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-05-17 13:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 21:23 [PATCH] reiserfs: add check for invalid 1st journal block Pavel Skripkin
2021-05-17 10:15 ` Jan Kara
2021-05-17 11:37 ` Pavel Skripkin
2021-05-17 12:15 ` [PATCH v2] " Pavel Skripkin
2021-05-17 13:08 ` Jan Kara [this message]
2021-06-08 10:44 ` Pavel Skripkin
2021-06-08 11:56 ` Jan Kara
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