File rubygem-rack-CVE-2023-27530.patch of Package rubygem-rack.28303
From 5f6e2fcbbdbff2dfaa21baa693e9d23d12ac1459 Mon Sep 17 00:00:00 2001
From: John Hawthorn <john@hawthorn.email>
Date: Thu, 8 Dec 2022 15:54:28 -0800
Subject: [PATCH] Limit all multipart parts, not just files
Previously we would limit the number of multipart parts which were
files, but not other parts. In some cases this could cause parsing of
maliciously crafted inputs to take longer than expected.
[CVE-2023-27530]
---
README.rdoc | 20 +++++++++++++++++---
lib/rack/multipart/parser.rb | 20 ++++++++++++++++----
lib/rack/utils.rb | 19 +++++++++++++++----
test/spec_multipart.rb | 12 ++++++++++++
test/spec_request.rb | 18 +++++++++++++++++-
5 files changed, 77 insertions(+), 12 deletions(-)
Index: rack-2.0.8/README.rdoc
===================================================================
--- rack-2.0.8.orig/README.rdoc
+++ rack-2.0.8/README.rdoc
@@ -189,16 +189,30 @@ This helps prevent a rogue client from f
Default to 65536 characters (4 kiB in worst case).
-=== multipart_part_limit
+=== multipart_file_limit
-The maximum number of parts a request can contain.
+The maximum number of parts with a filename a request can contain.
Accepting too many part can lead to the server running out of file handles.
The default is 128, which means that a single request can't upload more than 128 files at once.
Set to 0 for no limit.
-Can also be set via the RACK_MULTIPART_PART_LIMIT environment variable.
+Can also be set via the +RACK_MULTIPART_FILE_LIMIT+ environment variable.
+
+(This is also aliased as +multipart_part_limit+ and +RACK_MULTIPART_PART_LIMIT+ for compatibility)
+
+=== multipart_total_part_limit
+
+The maximum total number of parts a request can contain of any type, including
+both file and non-file form fields.
+
+The default is 4096, which means that a single request can't contain more than
+4096 parts.
+
+Set to 0 for no limit.
+
+Can also be set via the +RACK_MULTIPART_TOTAL_PART_LIMIT+ environment variable.
== History
Index: rack-2.0.8/lib/rack/multipart/parser.rb
===================================================================
--- rack-2.0.8.orig/lib/rack/multipart/parser.rb
+++ rack-2.0.8/lib/rack/multipart/parser.rb
@@ -3,6 +3,7 @@ require 'rack/utils'
module Rack
module Multipart
class MultipartPartLimitError < Errno::EMFILE; end
+ class MultipartTotalPartLimitError < StandardError; end
class Parser
BUFSIZE = 16384
@@ -138,7 +139,8 @@ module Rack
end
@mime_parts[mime_index] = klass.new(body, head, filename, content_type, name)
- check_open_files
+
+ check_part_limits
end
def on_mime_body mime_index, content
@@ -150,13 +152,23 @@ module Rack
private
- def check_open_files
- if Utils.multipart_part_limit > 0
- if @open_files >= Utils.multipart_part_limit
+ def check_part_limits
+ file_limit = Utils.multipart_file_limit
+ part_limit = Utils.multipart_total_part_limit
+
+ if file_limit && file_limit > 0
+ if @open_files >= file_limit
@mime_parts.each(&:close)
raise MultipartPartLimitError, 'Maximum file multiparts in content reached'
end
end
+
+ if part_limit && part_limit > 0
+ if @mime_parts.size >= part_limit
+ @mime_parts.each(&:close)
+ raise MultipartTotalPartLimitError, 'Maximum total multiparts in content reached'
+ end
+ end
end
end
Index: rack-2.0.8/lib/rack/utils.rb
===================================================================
--- rack-2.0.8.orig/lib/rack/utils.rb
+++ rack-2.0.8/lib/rack/utils.rb
@@ -53,13 +53,24 @@ module Rack
module_function :unescape
class << self
- attr_accessor :multipart_part_limit
+ attr_accessor :multipart_total_part_limit
+
+ attr_accessor :multipart_file_limit
+
+ # multipart_part_limit is the original name of multipart_file_limit, but
+ # the limit only counts parts with filenames.
+ alias multipart_part_limit multipart_file_limit
+ alias multipart_part_limit= multipart_file_limit=
end
- # The maximum number of parts a request can contain. Accepting too many part
- # can lead to the server running out of file handles.
+ # The maximum number of file parts a request can contain. Accepting too
+ # many parts can lead to the server running out of file handles.
# Set to `0` for no limit.
- self.multipart_part_limit = (ENV['RACK_MULTIPART_PART_LIMIT'] || 128).to_i
+ self.multipart_file_limit = (ENV['RACK_MULTIPART_PART_LIMIT'] || ENV['RACK_MULTIPART_FILE_LIMIT'] || 128).to_i
+
+ # The maximum total number of parts a request can contain. Accepting too
+ # many can lead to excessive memory use and parsing time.
+ self.multipart_total_part_limit = (ENV['RACK_MULTIPART_TOTAL_PART_LIMIT'] || 4096).to_i
def self.param_depth_limit
default_query_parser.param_depth_limit
Index: rack-2.0.8/test/spec_multipart.rb
===================================================================
--- rack-2.0.8.orig/test/spec_multipart.rb
+++ rack-2.0.8/test/spec_multipart.rb
@@ -561,6 +561,18 @@ Content-Type: image/jpeg\r
end
end
+ it "reach a multipart total limit" do
+ begin
+ previous_limit = Rack::Utils.multipart_total_part_limit
+ Rack::Utils.multipart_total_part_limit = 5
+
+ env = Rack::MockRequest.env_for '/', multipart_fixture(:three_files_three_fields)
+ lambda { Rack::Multipart.parse_multipart(env) }.must_raise Rack::Multipart::MultipartTotalPartLimitError
+ ensure
+ Rack::Utils.multipart_total_part_limit = previous_limit
+ end
+ end
+
it "return nil if no UploadedFiles were used" do
data = Rack::Multipart.build_multipart("people" => [{"submit-name" => "Larry", "files" => "contents"}])
data.must_be_nil
Index: rack-2.0.8/test/spec_request.rb
===================================================================
--- rack-2.0.8.orig/test/spec_request.rb
+++ rack-2.0.8/test/spec_request.rb
@@ -911,7 +911,7 @@ EOF
f[:tempfile].size.must_equal 76
end
- it "MultipartPartLimitError when request has too many multipart parts if limit set" do
+ it "MultipartPartLimitError when request has too many multipart file parts if limit set" do
begin
data = 10000.times.map { "--AaB03x\r\nContent-Type: text/plain\r\nContent-Disposition: attachment; name=#{SecureRandom.hex(10)}; filename=#{SecureRandom.hex(10)}\r\n\r\ncontents\r\n" }.join("\r\n")
data += "--AaB03x--\r"
@@ -927,6 +927,22 @@ EOF
end
end
+ it "MultipartPartLimitError when request has too many multipart total parts if limit set" do
+ begin
+ data = 10000.times.map { "--AaB03x\r\ncontent-type: text/plain\r\ncontent-disposition: attachment; name=#{SecureRandom.hex(10)}\r\n\r\ncontents\r\n" }.join("\r\n")
+ data += "--AaB03x--\r"
+
+ options = {
+ "CONTENT_TYPE" => "multipart/form-data; boundary=AaB03x",
+ "CONTENT_LENGTH" => data.length.to_s,
+ :input => StringIO.new(data)
+ }
+
+ request = make_request Rack::MockRequest.env_for("/", options)
+ lambda { request.POST }.must_raise Rack::Multipart::MultipartTotalPartLimitError
+ end
+ end
+
it 'closes tempfiles it created in the case of too many created' do
begin
data = 10000.times.map { "--AaB03x\r\nContent-Type: text/plain\r\nContent-Disposition: attachment; name=#{SecureRandom.hex(10)}; filename=#{SecureRandom.hex(10)}\r\n\r\ncontents\r\n" }.join("\r\n")
