From 40e5d2303ba1edc51beae66cc15263675980106a Mon Sep 17 00:00:00 2001 From: Akihiko Odaki Date: Mon, 26 Mar 2018 21:02:10 +0900 Subject: [PATCH] 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. --- app/helpers/jsonld_helper.rb | 2 +- app/lib/exceptions.rb | 1 + app/lib/provider_discovery.rb | 2 +- app/lib/request.rb | 31 +++++++++++++++- app/models/account.rb | 1 - app/models/application_record.rb | 1 + app/models/concerns/account_avatar.rb | 4 +- app/models/concerns/account_header.rb | 4 +- app/models/concerns/remotable.rb | 6 +-- app/models/custom_emoji.rb | 6 ++- app/models/media_attachment.rb | 7 ++-- app/models/preview_card.rb | 5 ++- app/services/fetch_atom_service.rb | 11 +++--- app/services/fetch_link_card_service.rb | 2 +- app/services/resolve_account_service.rb | 2 +- app/workers/pubsubhubbub/confirmation_worker.rb | 2 +- spec/lib/request_spec.rb | 49 +++++++++++++++++++++++++ spec/models/concerns/remotable_spec.rb | 5 ++- 18 files changed, 115 insertions(+), 26 deletions(-) diff --git a/app/helpers/jsonld_helper.rb b/app/helpers/jsonld_helper.rb index 957a2cb..dfb8fcb 100644 --- a/app/helpers/jsonld_helper.rb +++ b/app/helpers/jsonld_helper.rb @@ -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 diff --git a/app/lib/exceptions.rb b/app/lib/exceptions.rb index 95e3365..e88e98e 100644 --- a/app/lib/exceptions.rb +++ b/app/lib/exceptions.rb @@ -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 diff --git a/app/lib/provider_discovery.rb b/app/lib/provider_discovery.rb index bbd3a2d..3bec721 100644 --- a/app/lib/provider_discovery.rb +++ b/app/lib/provider_discovery.rb @@ -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 diff --git a/app/lib/request.rb b/app/lib/request.rb index 8a127c6..dca93a6 100644 --- a/app/lib/request.rb +++ b/app/lib/request.rb @@ -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 diff --git a/app/models/account.rb b/app/models/account.rb index 9a83d97..25e7d74 100644 --- a/app/models/account.rb +++ b/app/models/account.rb @@ -55,7 +55,6 @@ class Account < ApplicationRecord include AccountHeader include AccountInteractions include Attachmentable - include Remotable include Paginable enum protocol: [:ostatus, :activitypub] diff --git a/app/models/application_record.rb b/app/models/application_record.rb index 71fbba5..83134d4 100644 --- a/app/models/application_record.rb +++ b/app/models/application_record.rb @@ -2,4 +2,5 @@ class ApplicationRecord < ActiveRecord::Base self.abstract_class = true + include Remotable end diff --git a/app/models/concerns/account_avatar.rb b/app/models/concerns/account_avatar.rb index 9e34a94..2d5ebfc 100644 --- a/app/models/concerns/account_avatar.rb +++ b/app/models/concerns/account_avatar.rb @@ -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 diff --git a/app/models/concerns/account_header.rb b/app/models/concerns/account_header.rb index 04c576b..ef40b81 100644 --- a/app/models/concerns/account_header.rb +++ b/app/models/concerns/account_header.rb @@ -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 diff --git a/app/models/concerns/remotable.rb b/app/models/concerns/remotable.rb index 0f18c5d..3b8c507 100644 --- a/app/models/concerns/remotable.rb +++ b/app/models/concerns/remotable.rb @@ -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) diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb index a77b53c..476178e 100644 --- a/app/models/custom_emoji.rb +++ b/app/models/custom_emoji.rb @@ -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? diff --git a/app/models/media_attachment.rb b/app/models/media_attachment.rb index a4d9cd9..ac2aa7e 100644 --- a/app/models/media_attachment.rb +++ b/app/models/media_attachment.rb @@ -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? diff --git a/app/models/preview_card.rb b/app/models/preview_card.rb index 86eecdf..0c82f06 100644 --- a/app/models/preview_card.rb +++ b/app/models/preview_card.rb @@ -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? diff --git a/app/services/fetch_atom_service.rb b/app/services/fetch_atom_service.rb index 48ad5dc..62dea82 100644 --- a/app/services/fetch_atom_service.rb +++ b/app/services/fetch_atom_service.rb @@ -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' } diff --git a/app/services/fetch_link_card_service.rb b/app/services/fetch_link_card_service.rb index 26deb5e..d5920a4 100644 --- a/app/services/fetch_link_card_service.rb +++ b/app/services/fetch_link_card_service.rb @@ -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 diff --git a/app/services/resolve_account_service.rb b/app/services/resolve_account_service.rb index 034821d..744ea24 100644 --- a/app/services/resolve_account_service.rb +++ b/app/services/resolve_account_service.rb @@ -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 diff --git a/app/workers/pubsubhubbub/confirmation_worker.rb b/app/workers/pubsubhubbub/confirmation_worker.rb index cc2d122..c0e7b67 100644 --- a/app/workers/pubsubhubbub/confirmation_worker.rb +++ b/app/workers/pubsubhubbub/confirmation_worker.rb @@ -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 diff --git a/spec/lib/request_spec.rb b/spec/lib/request_spec.rb index 4d6b20d..939ac00 100644 --- a/spec/lib/request_spec.rb +++ b/spec/lib/request_spec.rb @@ -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 diff --git a/spec/models/concerns/remotable_spec.rb b/spec/models/concerns/remotable_spec.rb index 0b2dad2..b392337 100644 --- a/spec/models/concerns/remotable_spec.rb +++ b/spec/models/concerns/remotable_spec.rb @@ -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 }