From 9f1131f5972ba90c1c54c76cc97633447142b307 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Mon, 3 May 2010 15:19:53 -0700 Subject: add client_max_body_size config directive Since Rainbows! is supported when exposed directly to the Internet, administrators may want to limit the amount of data a user may upload in a single request body to prevent a denial-of-service via disk space exhaustion. This amount may be specified in bytes, the default limit being 1024*1024 bytes (1 megabyte). To override this default, a user may specify `client_max_body_size' in the Rainbows! block of their server config file: Rainbows! do client_max_body_size 10 * 1024 * 1024 end Clients that exceed the limit will get a "413 Request Entity Too Large" response if the request body is too large and the connection will close. For chunked requests, we have no choice but to interrupt during the client upload since we have no prior knowledge of the request body size. --- lib/rainbows/base.rb | 1 + lib/rainbows/const.rb | 2 + lib/rainbows/ev_core.rb | 42 ++++++++++++++++++++- lib/rainbows/http_server.rb | 12 ++++++ lib/rainbows/max_body.rb | 90 +++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 146 insertions(+), 1 deletion(-) create mode 100644 lib/rainbows/max_body.rb (limited to 'lib/rainbows') diff --git a/lib/rainbows/base.rb b/lib/rainbows/base.rb index 0cbc711..864b847 100644 --- a/lib/rainbows/base.rb +++ b/lib/rainbows/base.rb @@ -12,6 +12,7 @@ module Rainbows def init_worker_process(worker) super(worker) + MaxBody.setup G.tmp = worker.tmp # avoid spurious wakeups and blocking-accept() with 1.8 green threads diff --git a/lib/rainbows/const.rb b/lib/rainbows/const.rb index 08c4821..42906d3 100644 --- a/lib/rainbows/const.rb +++ b/lib/rainbows/const.rb @@ -24,5 +24,7 @@ module Rainbows # of the official spec, but for now it is "hack.io" CLIENT_IO = "hack.io".freeze + ERROR_413_RESPONSE = "HTTP/1.1 413 Request Entity Too Large\r\n\r\n" + end end diff --git a/lib/rainbows/ev_core.rb b/lib/rainbows/ev_core.rb index 682bdd6..d4ad040 100644 --- a/lib/rainbows/ev_core.rb +++ b/lib/rainbows/ev_core.rb @@ -49,7 +49,7 @@ module Rainbows write(EXPECT_100_RESPONSE) @env.delete(HTTP_EXPECT) end - @input = len && len <= MAX_BODY ? StringIO.new("") : Util.tmpio + @input = CapInput.new(len, self) @hp.filter_body(@buf2 = "", @buf) @input << @buf2 on_read("") @@ -73,5 +73,45 @@ module Rainbows handle_error(e) end + class CapInput < Struct.new(:io, :client, :bytes_left) + MAX_BODY = Unicorn::Const::MAX_BODY + Util = Unicorn::Util + + def self.err(client, msg) + client.write(Const::ERROR_413_RESPONSE) + client.quit + + # zip back up the stack + raise IOError, msg, [] + end + + def self.new(len, client) + max = Rainbows.max_bytes + if len + if max && (len > max) + err(client, "Content-Length too big: #{len} > #{max}") + end + len <= MAX_BODY ? StringIO.new("") : Util.tmpio + else + max ? super(Util.tmpio, client, max) : Util.tmpio + end + end + + def <<(buf) + if (self.bytes_left -= buf.size) < 0 + io.close + CapInput.err(client, "chunked request body too big") + end + io << buf + end + + def gets; io.gets; end + def each(&block); io.each(&block); end + def size; io.size; end + def rewind; io.rewind; end + def read(*args); io.read(*args); end + + end + end end diff --git a/lib/rainbows/http_server.rb b/lib/rainbows/http_server.rb index ea2e23f..50231ff 100644 --- a/lib/rainbows/http_server.rb +++ b/lib/rainbows/http_server.rb @@ -85,6 +85,18 @@ module Rainbows raise ArgumentError, "keepalive must be a non-negative Integer" G.kato = nr end + + def client_max_body_size(nr) + err = "client_max_body_size must be nil or a non-negative Integer" + case nr + when nil + when Integer + nr >= 0 or raise ArgumentError, err + else + raise ArgumentError, err + end + Rainbows.max_bytes = nr + end end end diff --git a/lib/rainbows/max_body.rb b/lib/rainbows/max_body.rb new file mode 100644 index 0000000..7450b2a --- /dev/null +++ b/lib/rainbows/max_body.rb @@ -0,0 +1,90 @@ +# -*- encoding: binary -*- +module Rainbows + +# middleware used to enforce client_max_body_size for TeeInput users, +# there is no need to configure this middleware manually, it will +# automatically be configured for you based on the client_max_body_size +# setting +class MaxBody < Struct.new(:app) + + # this is meant to be included in Unicorn::TeeInput (and derived + # classes) to limit body sizes + module Limit + Util = Unicorn::Util + + def initialize(socket, req, parser, buf) + self.len = parser.content_length + + max = Rainbows.max_bytes # never nil, see MaxBody.setup + if len && len > max + socket.write(Const::ERROR_413_RESPONSE) + socket.close + raise IOError, "Content-Length too big: #{len} > #{max}", [] + end + + self.req = req + self.parser = parser + self.buf = buf + self.socket = socket + self.buf2 = "" + if buf.size > 0 + parser.filter_body(buf2, buf) and finalize_input + buf2.size > max and raise IOError, "chunked request body too big", [] + end + self.tmp = len && len < Const::MAX_BODY ? StringIO.new("") : Util.tmpio + if buf2.size > 0 + tmp.write(buf2) + tmp.seek(0) + max -= buf2.size + end + @max_body = max + end + + def tee(length, dst) + rv = _tee(length, dst) + if rv && ((@max_body -= rv.size) < 0) + $stderr.puts "#@max_body TOO SMALL" + # make HttpParser#keepalive? => false to force an immediate disconnect + # after we write + parser.reset + throw :rainbows_EFBIG + end + rv + end + + end + + # this is called after forking, so it won't ever affect the master + # if it's reconfigured + def self.setup + Rainbows.max_bytes or return + case G.server.use + when :Rev, :EventMachine, :NeverBlock + return + when :Revactor + Rainbows::Revactor::TeeInput + else + Unicorn::TeeInput + end.class_eval do + alias _tee tee # can't use super here :< + remove_method :tee + remove_method :initialize if G.server.use != :Revactor # FIXME CODE SMELL + include Limit + end + + # force ourselves to the outermost middleware layer + G.server.app = MaxBody.new(G.server.app) + end + + # Rack response returned when there's an error + def err(env) + [ 413, [ %w(Content-Length 0), %w(Content-Type text/plain) ], [] ] + end + + # our main Rack middleware endpoint + def call(env) + catch(:rainbows_EFBIG) { app.call(env) } || err(env) + end + +end # class +end # module -- cgit v1.2.3-24-ge0c7