Validate HTTP response length while receiving (#6891)

to_s method of HTTP::Response keeps blocking while it receives the whole
content, no matter how it is big. This means it may waste time to receive
unacceptably large files. It may also consume memory and disk in the
process. This solves the inefficency by checking response length while
receiving.
This commit is contained in:
Akihiko Odaki 2018-03-26 21:02:10 +09:00 committed by Eugen Rochko
parent 18965cb0e6
commit 40e5d2303b
18 changed files with 115 additions and 26 deletions

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@ -61,7 +61,7 @@ module JsonLdHelper
def fetch_resource_without_id_validation(uri)
build_request(uri).perform do |response|
response.code == 200 ? body_to_json(response.to_s) : nil
response.code == 200 ? body_to_json(response.body_with_limit) : nil
end
end

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@ -5,6 +5,7 @@ module Mastodon
class NotPermittedError < Error; end
class ValidationError < Error; end
class HostValidationError < ValidationError; end
class LengthValidationError < ValidationError; end
class RaceConditionError < Error; end
class UnexpectedResponseError < Error

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@ -18,7 +18,7 @@ class ProviderDiscovery < OEmbed::ProviderDiscovery
else
Request.new(:get, url).perform do |res|
raise OEmbed::NotFound, url if res.code != 200 || res.mime_type != 'text/html'
Nokogiri::HTML(res.to_s)
Nokogiri::HTML(res.body_with_limit)
end
end

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@ -40,7 +40,7 @@ class Request
end
begin
yield response
yield response.extend(ClientLimit)
ensure
http_client.close
end
@ -99,6 +99,33 @@ class Request
@http_client ||= HTTP.timeout(:per_operation, timeout).follow(max_hops: 2)
end
module ClientLimit
def body_with_limit(limit = 1.megabyte)
raise Mastodon::LengthValidationError if content_length.present? && content_length > limit
if charset.nil?
encoding = Encoding::BINARY
else
begin
encoding = Encoding.find(charset)
rescue ArgumentError
encoding = Encoding::BINARY
end
end
contents = String.new(encoding: encoding)
while (chunk = readpartial)
contents << chunk
chunk.clear
raise Mastodon::LengthValidationError if contents.bytesize > limit
end
contents
end
end
class Socket < TCPSocket
class << self
def open(host, *args)
@ -118,5 +145,5 @@ class Request
end
end
private_constant :Socket
private_constant :ClientLimit, :Socket
end

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@ -55,7 +55,6 @@ class Account < ApplicationRecord
include AccountHeader
include AccountInteractions
include Attachmentable
include Remotable
include Paginable
enum protocol: [:ostatus, :activitypub]

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@ -2,4 +2,5 @@
class ApplicationRecord < ActiveRecord::Base
self.abstract_class = true
include Remotable
end

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@ -4,6 +4,7 @@ module AccountAvatar
extend ActiveSupport::Concern
IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
LIMIT = 2.megabytes
class_methods do
def avatar_styles(file)
@ -19,7 +20,8 @@ module AccountAvatar
# Avatar upload
has_attached_file :avatar, styles: ->(f) { avatar_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
validates_attachment_content_type :avatar, content_type: IMAGE_MIME_TYPES
validates_attachment_size :avatar, less_than: 2.megabytes
validates_attachment_size :avatar, less_than: LIMIT
remotable_attachment :avatar, LIMIT
end
def avatar_original_url

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@ -4,6 +4,7 @@ module AccountHeader
extend ActiveSupport::Concern
IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
LIMIT = 2.megabytes
class_methods do
def header_styles(file)
@ -19,7 +20,8 @@ module AccountHeader
# Header upload
has_attached_file :header, styles: ->(f) { header_styles(f) }, convert_options: { all: '-strip' }, processors: [:lazy_thumbnail]
validates_attachment_content_type :header, content_type: IMAGE_MIME_TYPES
validates_attachment_size :header, less_than: 2.megabytes
validates_attachment_size :header, less_than: LIMIT
remotable_attachment :header, LIMIT
end
def header_original_url

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@ -3,8 +3,8 @@
module Remotable
extend ActiveSupport::Concern
included do
attachment_definitions.each_key do |attachment_name|
class_methods do
def remotable_attachment(attachment_name, limit)
attribute_name = "#{attachment_name}_remote_url".to_sym
method_name = "#{attribute_name}=".to_sym
alt_method_name = "reset_#{attachment_name}!".to_sym
@ -33,7 +33,7 @@ module Remotable
File.extname(filename)
end
send("#{attachment_name}=", StringIO.new(response.to_s))
send("#{attachment_name}=", StringIO.new(response.body_with_limit(limit)))
send("#{attachment_name}_file_name=", basename + extname)
self[attribute_name] = url if has_attribute?(attribute_name)

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@ -19,6 +19,8 @@
#
class CustomEmoji < ApplicationRecord
LIMIT = 50.kilobytes
SHORTCODE_RE_FRAGMENT = '[a-zA-Z0-9_]{2,}'
SCAN_RE = /(?<=[^[:alnum:]:]|\n|^)
@ -29,14 +31,14 @@ class CustomEmoji < ApplicationRecord
has_attached_file :image, styles: { static: { format: 'png', convert_options: '-coalesce -strip' } }
validates_attachment :image, content_type: { content_type: 'image/png' }, presence: true, size: { in: 0..50.kilobytes }
validates_attachment :image, content_type: { content_type: 'image/png' }, presence: true, size: { less_than: LIMIT }
validates :shortcode, uniqueness: { scope: :domain }, format: { with: /\A#{SHORTCODE_RE_FRAGMENT}\z/ }, length: { minimum: 2 }
scope :local, -> { where(domain: nil) }
scope :remote, -> { where.not(domain: nil) }
scope :alphabetic, -> { order(domain: :asc, shortcode: :asc) }
include Remotable
remotable_attachment :image, LIMIT
def local?
domain.nil?

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@ -56,6 +56,8 @@ class MediaAttachment < ApplicationRecord
},
}.freeze
LIMIT = 8.megabytes
belongs_to :account, inverse_of: :media_attachments, optional: true
belongs_to :status, inverse_of: :media_attachments, optional: true
@ -64,10 +66,9 @@ class MediaAttachment < ApplicationRecord
processors: ->(f) { file_processors f },
convert_options: { all: '-quality 90 -strip' }
include Remotable
validates_attachment_content_type :file, content_type: IMAGE_MIME_TYPES + VIDEO_MIME_TYPES
validates_attachment_size :file, less_than: 8.megabytes
validates_attachment_size :file, less_than: LIMIT
remotable_attachment :file, LIMIT
validates :account, presence: true
validates :description, length: { maximum: 420 }, if: :local?

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@ -26,6 +26,7 @@
class PreviewCard < ApplicationRecord
IMAGE_MIME_TYPES = ['image/jpeg', 'image/png', 'image/gif'].freeze
LIMIT = 1.megabytes
self.inheritance_column = false
@ -36,11 +37,11 @@ class PreviewCard < ApplicationRecord
has_attached_file :image, styles: { original: { geometry: '400x400>', file_geometry_parser: FastGeometryParser } }, convert_options: { all: '-quality 80 -strip' }
include Attachmentable
include Remotable
validates :url, presence: true, uniqueness: true
validates_attachment_content_type :image, content_type: IMAGE_MIME_TYPES
validates_attachment_size :image, less_than: 1.megabytes
validates_attachment_size :image, less_than: LIMIT
remotable_attachment :image, LIMIT
before_save :extract_dimensions, if: :link?

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@ -38,13 +38,14 @@ class FetchAtomService < BaseService
return nil if response.code != 200
if response.mime_type == 'application/atom+xml'
[@url, { prefetched_body: response.to_s }, :ostatus]
[@url, { prefetched_body: response.body_with_limit }, :ostatus]
elsif ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(response.mime_type)
json = body_to_json(response.to_s)
body = response.body_with_limit
json = body_to_json(body)
if supported_context?(json) && json['type'] == 'Person' && json['inbox'].present?
[json['id'], { prefetched_body: response.to_s, id: true }, :activitypub]
[json['id'], { prefetched_body: body, id: true }, :activitypub]
elsif supported_context?(json) && json['type'] == 'Note'
[json['id'], { prefetched_body: response.to_s, id: true }, :activitypub]
[json['id'], { prefetched_body: body, id: true }, :activitypub]
else
@unsupported_activity = true
nil
@ -61,7 +62,7 @@ class FetchAtomService < BaseService
end
def process_html(response)
page = Nokogiri::HTML(response.to_s)
page = Nokogiri::HTML(response.body_with_limit)
json_link = page.xpath('//link[@rel="alternate"]').find { |link| ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(link['type']) }
atom_link = page.xpath('//link[@rel="alternate"]').find { |link| link['type'] == 'application/atom+xml' }

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@ -45,7 +45,7 @@ class FetchLinkCardService < BaseService
Request.new(:get, @url).perform do |res|
if res.code == 200 && res.mime_type == 'text/html'
@html = res.to_s
@html = res.body_with_limit
@html_charset = res.charset
else
@html = nil

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@ -181,7 +181,7 @@ class ResolveAccountService < BaseService
@atom_body = Request.new(:get, atom_url).perform do |response|
raise Mastodon::UnexpectedResponseError, response unless response.code == 200
response.to_s
response.body_with_limit
end
end

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@ -57,7 +57,7 @@ class Pubsubhubbub::ConfirmationWorker
def callback_get_with_params
Request.new(:get, subscription.callback_url, params: callback_params).perform do |response|
@callback_response_body = response.body.to_s
@callback_response_body = response.body_with_limit
end
end

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@ -1,6 +1,7 @@
# frozen_string_literal: true
require 'rails_helper'
require 'securerandom'
describe Request do
subject { Request.new(:get, 'http://example.com') }
@ -64,6 +65,12 @@ describe Request do
expect_any_instance_of(HTTP::Client).to receive(:close)
expect { |block| subject.perform &block }.to yield_control
end
it 'returns response which implements body_with_limit' do
subject.perform do |response|
expect(response).to respond_to :body_with_limit
end
end
end
context 'with private host' do
@ -81,4 +88,46 @@ describe Request do
end
end
end
describe "response's body_with_limit method" do
it 'rejects body more than 1 megabyte by default' do
stub_request(:any, 'http://example.com').to_return(body: SecureRandom.random_bytes(2.megabytes))
expect { subject.perform { |response| response.body_with_limit } }.to raise_error Mastodon::LengthValidationError
end
it 'accepts body less than 1 megabyte by default' do
stub_request(:any, 'http://example.com').to_return(body: SecureRandom.random_bytes(2.kilobytes))
expect { subject.perform { |response| response.body_with_limit } }.not_to raise_error
end
it 'rejects body by given size' do
stub_request(:any, 'http://example.com').to_return(body: SecureRandom.random_bytes(2.kilobytes))
expect { subject.perform { |response| response.body_with_limit(1.kilobyte) } }.to raise_error Mastodon::LengthValidationError
end
it 'rejects too large chunked body' do
stub_request(:any, 'http://example.com').to_return(body: SecureRandom.random_bytes(2.megabytes), headers: { 'Transfer-Encoding' => 'chunked' })
expect { subject.perform { |response| response.body_with_limit } }.to raise_error Mastodon::LengthValidationError
end
it 'rejects too large monolithic body' do
stub_request(:any, 'http://example.com').to_return(body: SecureRandom.random_bytes(2.megabytes), headers: { 'Content-Length' => 2.megabytes })
expect { subject.perform { |response| response.body_with_limit } }.to raise_error Mastodon::LengthValidationError
end
it 'uses binary encoding if Content-Type does not tell encoding' do
stub_request(:any, 'http://example.com').to_return(body: '', headers: { 'Content-Type' => 'text/html' })
expect(subject.perform { |response| response.body_with_limit.encoding }).to eq Encoding::BINARY
end
it 'uses binary encoding if Content-Type tells unknown encoding' do
stub_request(:any, 'http://example.com').to_return(body: '', headers: { 'Content-Type' => 'text/html; charset=unknown' })
expect(subject.perform { |response| response.body_with_limit.encoding }).to eq Encoding::BINARY
end
it 'uses encoding specified by Content-Type' do
stub_request(:any, 'http://example.com').to_return(body: '', headers: { 'Content-Type' => 'text/html; charset=UTF-8' })
expect(subject.perform { |response| response.body_with_limit.encoding }).to eq Encoding::UTF_8
end
end
end

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@ -29,7 +29,10 @@ RSpec.describe Remotable do
context 'Remotable module is included' do
before do
class Foo; include Remotable; end
class Foo
include Remotable
remotable_attachment :hoge, 1.kilobyte
end
end
let(:attribute_name) { "#{hoge}_remote_url".to_sym }