From patchwork Tue Mar 15 22:16:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Burkov X-Patchwork-Id: 12781905 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 BC127C4167B for ; Tue, 15 Mar 2022 22:16:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352150AbiCOWRZ (ORCPT ); Tue, 15 Mar 2022 18:17:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352148AbiCOWRY (ORCPT ); Tue, 15 Mar 2022 18:17:24 -0400 Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 247CF5C379; Tue, 15 Mar 2022 15:16:12 -0700 (PDT) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 7CD8E5C0200; Tue, 15 Mar 2022 18:16:11 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute5.internal (MEProxy); Tue, 15 Mar 2022 18:16:11 -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=B7aWnl6o+/fwtAlM3Qm/DL+gMV/6dV zUA8OGnisteTc=; b=MwWR1209ql1+TZJio4Qb1HZOmmvUK0JhtWX6BTYueS07qI OFHYI2sA5PLBB4wB97KfB9AH05qTERzvFjlkWXb0HBgb5WZ8nAIvgHbI+WfBkxPC ClBM7R1SF63sGhE7on/vmOak8vkQ5FxJ0s1qaPK9f+V42+cOJLc1YJE5tuTwITs5 Jnp9iHv+K30TKTofsJcpB4PNl8scHXsn//PuZwLx9p9wLrf1enz0JiMfV9E9uxxJ CUFcLJfKDshqOoQlgGkiA63GeQDag4TPMBjPjFg9fS0g6gd7V85RFkKHypfv3rq/ HkfWfGynx0SlE1unkbq9+1Wd1ITFRPtx8toOhxbA== 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=B7aWnl 6o+/fwtAlM3Qm/DL+gMV/6dVzUA8OGnisteTc=; b=Vr50i+E08m8jNox/C80lPu svvv7wIk7q8RXiuBbUMMMnyFwDxLys+aj4c4wr26X11vrfzBCI1CDUuwGAN7Ll5f NIFBZtXN2eVi4wFBLfNU/fo2cdhGAt2x04C86FpJpIYyCPTNySjdt7LQM8I+NIOC yANbzN8wbumRxz271Gm1uEAJDt1a1SA0rMm6+tejRJLyLoujsQehSUZrCoCQIgkq QGXmB43fYwjjJMZQJhyrhxOOE6ab0CGeAUMvr/9kyhdTWj5tD4psIXDdcdUNQbmf jMn8vi21qqlg1/61t0PnesACHuOuHZg2mu3FIO2yU7vO8ZjrReisnk5DLCB4sKZA == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudeftddgudehjecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffojghfggfgsedtke ertdertddtnecuhfhrohhmpeeuohhrihhsuceuuhhrkhhovhcuoegsohhrihhssegsuhhr rdhioheqnecuggftrfgrthhtvghrnhepieeuffeuvdeiueejhfehiefgkeevudejjeejff evvdehtddufeeihfekgeeuheelnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghm pehmrghilhhfrhhomhepsghorhhishessghurhdrihho X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 15 Mar 2022 18:16:11 -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 v7 5/5] generic: test fs-verity EFBIG scenarios Date: Tue, 15 Mar 2022 15:16:01 -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-btrfs@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 db03510e..2b3d4dae 100644 --- a/common/verity +++ b/common/verity @@ -348,3 +348,14 @@ _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