From patchwork Wed Mar 16 20:25:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Burkov X-Patchwork-Id: 12783147 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 84995C433EF for ; Wed, 16 Mar 2022 20:25:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357938AbiCPU0v (ORCPT ); Wed, 16 Mar 2022 16:26:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357916AbiCPU0u (ORCPT ); Wed, 16 Mar 2022 16:26:50 -0400 Received: from wout5-smtp.messagingengine.com (wout5-smtp.messagingengine.com [64.147.123.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9454849F03; Wed, 16 Mar 2022 13:25:32 -0700 (PDT) Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.west.internal (Postfix) with ESMTP id CFB0E3201F7B; Wed, 16 Mar 2022 16:25:31 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Wed, 16 Mar 2022 16:25:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bur.io; h=cc :content-transfer-encoding:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm1; bh=K9PPSGkc2e5BRTkUvpmHCZvk339Rzh ttEZFwKOqMMTM=; b=QZwCQrMVxsUYgiOup+6eW/k2eilhcQj50NlOoAWpBSLplJ aQVBFsSR45SPW7Fvi/bA76eY8aezlPGMRLANwEiCGSyiEb2SC76WVMjj9idnxwdF V6/1ctxhYrAaykXHvTN5X+wTnJOAHJGjc1Bj8rBD+ZBDEgPZ8M5lL9dWDsfKFTMF q7k9e4GA0ef8wN/NQRvnsBirngOVhOXAn9wtS9EOTAGDlbasf6k8iZITOX+Oacmr uTCDSjiWJRf8tZpIQt2uE746MNxBCP2IexdWw23lKT8c4qiNcZWy7Sqja3RpZ6UZ J5IlTcI6bgUYt2ybJBk5Usj9tcfPenOdScVWdZJg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:date :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:sender:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=K9PPSG kc2e5BRTkUvpmHCZvk339RzhttEZFwKOqMMTM=; b=CbGiL9QGIYdvZQXYunW2fY rFE0oBNWukDpC4pnV8JOQ5TPN+wlKyFFbo81ajWjsg+TcaDvXjKna8ncl6iSSDPc kPq+k+AopkQm2tzgI7cpKEsxBY6ceJk+hpCuFOshxCNCM3MwWMM62gR86QW8i6E0 cNNZmSj3miQq3a+cSrwJW27fwugTRgGumHLpmLXZ2ecFulXRfkRY05fsDcSIbxVM JmoIlZBHv3We0bbm+cgJtj1HN4o4vBjwWjKx6viMQxfFocsz2ecjcFWvIAQ1Lemp ohUZEHSS+fk5DwCxZGVEsKTn9CVJvI5SwETMsS4vs8UqF1AOmD/0xk8XGukny1nA == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudefvddgudefgecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffojghfggfgsedtke ertdertddtnecuhfhrohhmpeeuohhrihhsuceuuhhrkhhovhcuoegsohhrihhssegsuhhr rdhioheqnecuggftrfgrthhtvghrnhepieeuffeuvdeiueejhfehiefgkeevudejjeejff evvdehtddufeeihfekgeeuheelnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghm pehmrghilhhfrhhomhepsghorhhishessghurhdrihho X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 16 Mar 2022 16:25:30 -0400 (EDT) From: Boris Burkov To: fstests@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v8 5/5] generic: test fs-verity EFBIG scenarios Date: Wed, 16 Mar 2022 13:25:15 -0700 Message-Id: X-Mailer: git-send-email 2.35.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org btrfs, ext4, and f2fs cache the Merkle tree past EOF, which restricts the maximum file size beneath the normal maximum. Test the logic in those filesystems against files with sizes near the maximum. To work properly, this does require some understanding of the practical but not standardized layout of the Merkle tree. This is a bit unpleasant and could make the test incorrect in the future, if the implementation changes. On the other hand, it feels quite useful to test this tricky edge case. It could perhaps be made more generic by adding some ioctls to let the file system communicate the maximum file size for a verity file or some information about the storage of the Merkle tree. Signed-off-by: Boris Burkov Reviewed-by: Eric Biggers --- common/verity | 11 ++++++++ tests/generic/690 | 64 +++++++++++++++++++++++++++++++++++++++++++ tests/generic/690.out | 7 +++++ 3 files changed, 82 insertions(+) create mode 100755 tests/generic/690 create mode 100644 tests/generic/690.out diff --git a/common/verity b/common/verity index c6a47013..8d08d3ea 100644 --- a/common/verity +++ b/common/verity @@ -342,3 +342,14 @@ _fsv_scratch_corrupt_merkle_tree() ;; esac } + +_require_fsverity_max_file_size_limit() +{ + case $FSTYP in + btrfs|ext4|f2fs) + ;; + *) + _notrun "$FSTYP does not store verity data past EOF; no special file size limit" + ;; + esac +} diff --git a/tests/generic/690 b/tests/generic/690 new file mode 100755 index 00000000..afdd95f2 --- /dev/null +++ b/tests/generic/690 @@ -0,0 +1,64 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2021 Facebook, Inc. All Rights Reserved. +# +# FS QA Test 690 +# +# fs-verity requires the filesystem to decide how it stores the Merkle tree, +# which can be quite large. +# It is convenient to treat the Merkle tree as past EOF, and ext4, f2fs, and +# btrfs do so in at least some fashion. This leads to an edge case where a +# large file can be under the file system file size limit, but trigger EFBIG +# on enabling fs-verity. Test enabling verity on some large files to exercise +# EFBIG logic for filesystems with fs-verity specific limits. +# +. ./common/preamble +_begin_fstest auto quick verity + + +# Import common functions. +. ./common/filter +. ./common/verity + +# real QA test starts here +_supported_fs generic +_require_test +_require_math +_require_scratch_verity +_require_fsverity_max_file_size_limit + +_scratch_mkfs_verity &>> $seqres.full +_scratch_mount + +fsv_file=$SCRATCH_MNT/file.fsv + +max_sz=$(_get_max_file_size) +_fsv_scratch_begin_subtest "way too big: fail on first merkle block" +truncate -s $max_sz $fsv_file +_fsv_enable $fsv_file |& _filter_scratch + +# The goal of this second test is to make a big enough file that we trip the +# EFBIG codepath, but not so big that we hit it immediately when writing the +# first Merkle leaf. +# +# The Merkle tree is stored with the leaf node level (L0) last, but it is +# written first. To get an interesting overflow, we need the maximum file size +# (MAX) to be in the middle of L0 -- ideally near the beginning of L0 so that we +# don't have to write many blocks before getting an error. +# +# With SHA-256 and 4K blocks, there are 128 hashes per block. Thus, ignoring +# padding, L0 is 1/128 of the file size while the other levels in total are +# 1/128**2 + 1/128**3 + 1/128**4 + ... = 1/16256 of the file size. So still +# ignoring padding, for L0 start exactly at MAX, the file size must be s such +# that s + s/16256 = MAX, i.e. s = MAX * (16256/16257). Then to get a file size +# where MAX occurs *near* the start of L0 rather than *at* the start, we can +# just subtract an overestimate of the padding: 64K after the file contents, +# then 4K per level, where the consideration of 8 levels is sufficient. +sz=$(echo "scale=20; $max_sz * (16256/16257) - 65536 - 4096*8" | $BC -q | cut -d. -f1) +_fsv_scratch_begin_subtest "still too big: fail on first invalid merkle block" +truncate -s $sz $fsv_file +_fsv_enable $fsv_file |& _filter_scratch + +# success, all done +status=0 +exit diff --git a/tests/generic/690.out b/tests/generic/690.out new file mode 100644 index 00000000..a3e2b9b9 --- /dev/null +++ b/tests/generic/690.out @@ -0,0 +1,7 @@ +QA output created by 690 + +# way too big: fail on first merkle block +ERROR: FS_IOC_ENABLE_VERITY failed on 'SCRATCH_MNT/file.fsv': File too large + +# still too big: fail on first invalid merkle block +ERROR: FS_IOC_ENABLE_VERITY failed on 'SCRATCH_MNT/file.fsv': File too large