gitlab-org--gitlab-foss/config/initializers/http_hostname_override.rb
Douwe Maan a9bcddee4c Protect Gitlab::HTTP against DNS rebinding attack
Gitlab::HTTP now resolves the hostname only once, verifies the IP is not
blocked, and then uses the same IP to perform the actual request, while
passing the original hostname in the `Host` header and SSL SNI field.
2019-05-30 10:47:31 -03:00

49 lines
1.4 KiB
Ruby

# This override allows passing `@hostname_override` to the SNI protocol,
# which is used to lookup the correct SSL certificate in the
# request handshake process.
#
# Given we've forced the HTTP request to be sent to the resolved
# IP address in a few scenarios (e.g.: `Gitlab::HTTP` through
# `Gitlab::UrlBlocker.validate!`), we need to provide the _original_
# hostname via SNI in order to have a clean connection setup.
#
# This is ultimately needed in order to avoid DNS rebinding attacks
# through HTTP requests.
#
class OpenSSL::SSL::SSLContext
attr_accessor :hostname_override
end
class OpenSSL::SSL::SSLSocket
module HostnameOverride
# rubocop: disable Gitlab/ModuleWithInstanceVariables
def hostname=(hostname)
super(@context.hostname_override || hostname)
end
def post_connection_check(hostname)
super(@context.hostname_override || hostname)
end
# rubocop: enable Gitlab/ModuleWithInstanceVariables
end
prepend HostnameOverride
end
class Net::HTTP
attr_accessor :hostname_override
SSL_IVNAMES << :@hostname_override
SSL_ATTRIBUTES << :hostname_override
module HostnameOverride
def addr_port
return super unless hostname_override
addr = hostname_override
default_port = use_ssl? ? Net::HTTP.https_default_port : Net::HTTP.http_default_port
default_port == port ? addr : "#{addr}:#{port}"
end
end
prepend HostnameOverride
end