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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04955C433FE for ; Tue, 18 Oct 2022 00:18:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232086AbiJRASp (ORCPT ); Mon, 17 Oct 2022 20:18:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231901AbiJRAP7 (ORCPT ); Mon, 17 Oct 2022 20:15:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68220895C4; Mon, 17 Oct 2022 17:13:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 20D9E612D8; Tue, 18 Oct 2022 00:09:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E91DC433B5; Tue, 18 Oct 2022 00:09:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666051797; bh=3WXnQWQsXlcnk4Gq3XwiR1UPflW6u08WFIL/aKLKN9Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cHCuGCrVjpCxQXawBhhif6wnKjnh54QUb89OuOdhG8826+A2vAvjr5QFZP7zHms4B TmVqdIwhPPP6msi+e37VsK3bMEXwqJjOhLqhtFqNk94tR59/E+/KEJXvkw9OpUFR7p QDymIEhindBuXZkVB5jUi5Pi+DrLtdJr+wCi+LuazOXL8jUgWJTNGE9ULmJMlWLxqr WkC+yFmBD5HU8Xyx9KsC1jK3ola18F66eLuo2K9qsK6IdMK+i2LnUYCIJCEgqhdc5N ZBCNE2TyG7/r6q6gkYL+sZwJz0GjlvvMG55E8C5ftJj13IAddmoh7OSJKp9Te51EN0 Ume8QXmytrdrw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrew Price , syzbot+dcf33a7aae997956fe06@syzkaller.appspotmail.com, Andreas Gruenbacher , Sasha Levin , rpeterso@redhat.com, cluster-devel@redhat.com Subject: [PATCH AUTOSEL 5.15 09/21] gfs2: Check sb_bsize_shift after reading superblock Date: Mon, 17 Oct 2022 20:09:28 -0400 Message-Id: <20221018000940.2731329-9-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221018000940.2731329-1-sashal@kernel.org> References: <20221018000940.2731329-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrew Price [ Upstream commit 670f8ce56dd0632dc29a0322e188cc73ce3c6b92 ] Fuzzers like to scribble over sb_bsize_shift but in reality it's very unlikely that this field would be corrupted on its own. Nevertheless it should be checked to avoid the possibility of messy mount errors due to bad calculations. It's always a fixed value based on the block size so we can just check that it's the expected value. Tested with: mkfs.gfs2 -O -p lock_nolock /dev/vdb for i in 0 -1 64 65 32 33; do gfs2_edit -p sb field sb_bsize_shift $i /dev/vdb mount /dev/vdb /mnt/test && umount /mnt/test done Before this patch we get a withdraw after [ 76.413681] gfs2: fsid=loop0.0: fatal: invalid metadata block [ 76.413681] bh = 19 (type: exp=5, found=4) [ 76.413681] function = gfs2_meta_buffer, file = fs/gfs2/meta_io.c, line = 492 and with UBSAN configured we also get complaints like [ 76.373395] UBSAN: shift-out-of-bounds in fs/gfs2/ops_fstype.c:295:19 [ 76.373815] shift exponent 4294967287 is too large for 64-bit type 'long unsigned int' After the patch, these complaints don't appear, mount fails immediately and we get an explanation in dmesg. Reported-by: syzbot+dcf33a7aae997956fe06@syzkaller.appspotmail.com Signed-off-by: Andrew Price Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/ops_fstype.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index f461a365eb38..fb3b48837083 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -180,7 +180,10 @@ static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent) pr_warn("Invalid block size\n"); return -EINVAL; } - + if (sb->sb_bsize_shift != ffs(sb->sb_bsize) - 1) { + pr_warn("Invalid block size shift\n"); + return -EINVAL; + } return 0; } -- 2.35.1