From patchwork Tue Apr 26 22:40:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Burkov X-Patchwork-Id: 12828031 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 88247C433F5 for ; Tue, 26 Apr 2022 22:40:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355914AbiDZWnh (ORCPT ); Tue, 26 Apr 2022 18:43:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355909AbiDZWng (ORCPT ); Tue, 26 Apr 2022 18:43:36 -0400 Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2D3314096; Tue, 26 Apr 2022 15:40:27 -0700 (PDT) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 531905C0164; Tue, 26 Apr 2022 18:40:27 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Tue, 26 Apr 2022 18:40:27 -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; t=1651012827; x=1651099227; bh=I+ HxmkzZNhZ0P3kPMHejig53XLe7o7IFnigO5Hnymis=; b=dD5voST/UNPV3LAvqm 9YFkDYbX/aUWFcvPheEKOB9ZesQWvlj58+IiWZRtxd1QaRkQk3JaiHN9PI8Dy+9j eB3RDd1Ftkh97dfpVyWZnFYuK9CYmeAP7LeUmHIqjFz2UuwEyWw1/Jx22QX6WuGC qMtuV7UMyBjN25ZtcWAkrRAvvx+t2pgHPLhTUdf2DhzMqeJPoyDU7MfmPztWwNwj boiQCoPDSIJEgaRKQ2bx2d5Te0AC71+KDZhYOn1qDuwYfGwMaf5KnI1iE4P2qxMb AwDVTdcwghlpPiVh46MyJxTmXQ/lxO0U6kNOoHRyXQ08VGMdPriofvMHEks8p8eq j2Iw== 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=fm1; t= 1651012827; x=1651099227; bh=I+HxmkzZNhZ0P3kPMHejig53XLe7o7IFnig O5Hnymis=; b=LwFgGjVq0k+hb1XkNxidvjbI/g1kz0XShklE4qfDjS8mh38w/pt oHrVmFb7Ba7VfJWgF2+lYXwvf70RTmRKIpH0LakWwHxKQCi9/+vrwkMDEgDcajGh Hrx/GO4OCVzP8H1GA/B2aK9cpdIDpwLb58lmDgJ0MoSEanZApwrtzECHv9VM5PKZ Ngl8F3/psUE8XYHS/oWAafr78nlsPfUjqnPljP+CItLGFIxs/N1mliepHCOyXD9e HqzWHei7AAd0rNOf2derMPLJ3ZLtuCNsxcDPisHmW2c4Qz7lSWdK6DsqpIniBr9Q xJ+PNfz3Z0OnrpWVhhIpQJ8XEHvj7EqbhZg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrudeggddufecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffojghfggfgsedtkeertd ertddtnecuhfhrohhmpeeuohhrihhsuceuuhhrkhhovhcuoegsohhrihhssegsuhhrrdhi oheqnecuggftrfgrthhtvghrnhepieeuffeuvdeiueejhfehiefgkeevudejjeejffevvd ehtddufeeihfekgeeuheelnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehm rghilhhfrhhomhepsghorhhishessghurhdrihho X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 26 Apr 2022 18:40:26 -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 v9 5/5] generic: test fs-verity EFBIG scenarios Date: Tue, 26 Apr 2022 15:40:16 -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: fstests@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 8cde2737..657af8aa 100644 --- a/common/verity +++ b/common/verity @@ -347,3 +347,14 @@ _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