From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 5.4 14/74] reiserfs: add check for invalid 1st journal block Date: Tue, 6 Jul 2021 07:24:02 -0400 Message-ID: <20210706112502.2064236-14-sashal@kernel.org> References: <20210706112502.2064236-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625570721; bh=QPgQE2G1/gCeuN/4WN1kwXiMfVifxrdMfmmLcWoYOf8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DRWqc8bbvOxzVj9IzbXjPTJD8/9AqXkU5IAhz+Es6FbBXOuoeVJESdB6al4BH9Cih G5on2aKtzwPdHp8gerKKzt+BMu/e+3sVg6a/21EGNjSGz0Ew3fuNuFWh5BeLzZLOoM 5D4JEIYV7+EA4VYIbW9cEUWFpIeFkF14Iq1zHXRA82NXXyx9zCNck5IilHmQtdK62b 89ztS3zCYck1y/Rx6TeSFmBttwlgkY9xtZyWO1VNxqZWzGbtXuLnihArf5LR2i7M87 GxfMqX3FCAsbyRiM6vVywy9YwjPWif9ZQ2jvDMOZxaOKTKTQ2HsWA8KXY+Yw8NFiAX v45Nit+3bhVgQ== In-Reply-To: <20210706112502.2064236-1-sashal@kernel.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Pavel Skripkin , syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com, Jan Kara , Sasha Levin , reiserfs-devel@vger.kernel.org From: Pavel Skripkin [ Upstream commit a149127be52fa7eaf5b3681a0317a2bbb772d5a9 ] 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(). Link: https://lore.kernel.org/r/20210517121545.29645-1-paskripkin@gmail.com Reported-by: syzbot+0ba9909df31c6a36974d@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Signed-off-by: Jan Kara Signed-off-by: Sasha Levin --- fs/reiserfs/journal.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index 4b3e3e73b512..09ad022a78a5 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -2763,6 +2763,20 @@ 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"); -- 2.30.2