From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EEC915AC5 for ; Tue, 25 Jul 2023 10:51:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 839B4C433CB; Tue, 25 Jul 2023 10:51:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690282318; bh=ZOoUxsDyKwEulenjDn/1naBRUgbYK9tIpKiPvo2Coh8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q6POmwAz2Mo3cWdy3vezZooG8Gn9lVLqsbotnY5Ys928EucylNtUSOB0PW5PiMJ24 doXrjM62uMeAUznZZHiNDJchuoTqPS9gJpzag9QpS/fbsMLjqxmgJlVEfCCiRnPlml T+bDDeHS4ovEmIr97rvvdy6XRKaDmKRLLxw9H1yU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+f1faa20eec55e0c8644c@syzkaller.appspotmail.com, Immad Mir , Dave Kleikamp , Sasha Levin Subject: [PATCH 6.4 086/227] [PATCH AUTOSEL 5.4 11/12] FS: JFS: Fix null-ptr-deref Read in txBegin Date: Tue, 25 Jul 2023 12:44:13 +0200 Message-ID: <20230725104518.302403587@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104514.821564989@linuxfoundation.org> References: <20230725104514.821564989@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 47cfdc338d674d38f4b2f22b7612cc6a2763ba27 ] Syzkaller reported an issue where txBegin may be called on a superblock in a read-only mounted filesystem which leads to NULL pointer deref. This could be solved by checking if the filesystem is read-only before calling txBegin, and returning with appropiate error code. Reported-By: syzbot+f1faa20eec55e0c8644c@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=be7e52c50c5182cc09a09ea6fc456446b2039de3 Signed-off-by: Immad Mir Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin --- fs/jfs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/jfs/namei.c +++ b/fs/jfs/namei.c @@ -799,6 +799,11 @@ static int jfs_link(struct dentry *old_d if (rc) goto out; + if (isReadOnly(ip)) { + jfs_error(ip->i_sb, "read-only filesystem\n"); + return -EROFS; + } + tid = txBegin(ip->i_sb, 0); mutex_lock_nested(&JFS_IP(dir)->commit_mutex, COMMIT_MUTEX_PARENT);