From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 084C7C4741F for ; Mon, 9 Nov 2020 13:37:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A599620658 for ; Mon, 9 Nov 2020 13:37:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604929065; bh=KkE9599z8X6ZModkrwGfEaS+5dmdtW0p7PPEl6w++O4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QLSxr4rRNskt3FAsC464HKCL98DUoF3l7K/7wesbnAInqwSPgNuKijTMHpwPBho/g GaEoREuRR0PlIzJWuPynkoaYbMPRENd3ujDkbKijdWQjbFlyOe2gJ4hXqHMh3/u6Xu LFhO/S8IohVZw8zoh58y3TdzPpIGmlVLRzy8+il0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730696AbgKINEH (ORCPT ); Mon, 9 Nov 2020 08:04:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:55548 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730040AbgKINBf (ORCPT ); Mon, 9 Nov 2020 08:01:35 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E48C520684; Mon, 9 Nov 2020 13:01:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604926894; bh=KkE9599z8X6ZModkrwGfEaS+5dmdtW0p7PPEl6w++O4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bdqO8vJhGHJWvLr8CmM/FRzDF5bkB97Z35LCu2pt3gDm7LurdfT/VeFJjzZePM8xU MaQMhkXTX2qiKrD26NAsyly1v242Sn65j2z+L+XeniQJ6yRjWa2w//m0i5fAJI+pcq Bobmg8SOcsKCyiEhSSIX9w5nAX5rDky1sTnP7VaU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+af90d47a37376844e731@syzkaller.appspotmail.com, Andrew Price , Anant Thazhemadam , Andreas Gruenbacher , Sasha Levin Subject: [PATCH 4.9 040/117] gfs2: add validation checks for size of superblock Date: Mon, 9 Nov 2020 13:54:26 +0100 Message-Id: <20201109125027.557743995@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125025.630721781@linuxfoundation.org> References: <20201109125025.630721781@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anant Thazhemadam [ Upstream commit 0ddc5154b24c96f20e94d653b0a814438de6032b ] In gfs2_check_sb(), no validation checks are performed with regards to the size of the superblock. syzkaller detected a slab-out-of-bounds bug that was primarily caused because the block size for a superblock was set to zero. A valid size for a superblock is a power of 2 between 512 and PAGE_SIZE. Performing validation checks and ensuring that the size of the superblock is valid fixes this bug. Reported-by: syzbot+af90d47a37376844e731@syzkaller.appspotmail.com Tested-by: syzbot+af90d47a37376844e731@syzkaller.appspotmail.com Suggested-by: Andrew Price Signed-off-by: Anant Thazhemadam [Minor code reordering.] Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/ops_fstype.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index bb5ddaabc218b..0e6fa91f4c8f2 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -160,15 +160,19 @@ static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent) return -EINVAL; } - /* If format numbers match exactly, we're done. */ - - if (sb->sb_fs_format == GFS2_FORMAT_FS && - sb->sb_multihost_format == GFS2_FORMAT_MULTI) - return 0; + if (sb->sb_fs_format != GFS2_FORMAT_FS || + sb->sb_multihost_format != GFS2_FORMAT_MULTI) { + fs_warn(sdp, "Unknown on-disk format, unable to mount\n"); + return -EINVAL; + } - fs_warn(sdp, "Unknown on-disk format, unable to mount\n"); + if (sb->sb_bsize < 512 || sb->sb_bsize > PAGE_SIZE || + (sb->sb_bsize & (sb->sb_bsize - 1))) { + pr_warn("Invalid superblock size\n"); + return -EINVAL; + } - return -EINVAL; + return 0; } static void end_bio_io_page(struct bio *bio) -- 2.27.0