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# Prevent HTTP requests to be made into private network (in Ruby!) | |
# Just an example, don't use it in production! | |
require 'http' | |
require 'resolv' | |
class StaticResolveTCPSocket | |
def initialize(lookup) | |
@lookup = lookup.dup | |
@lookup.default_proc = proc do |_h, host| | |
raise "Unresolvable host #{host}!" | |
end | |
end | |
def open(host, port) | |
TCPSocket.open(@lookup[host], port) | |
end | |
end | |
IPV4_PRIVATE_BLOCKS = %w[ | |
10.0.0.0/8 | |
172.16.0.0/12 | |
192.168.0.0/16 | |
].map(&IPAddr.method(:new)).freeze | |
def validate_addr!(addr) | |
addr = IPAddr.new(addr) if addr.is_a? String | |
raise "#{addr} belongs to a private network!" if IPV4_PRIVATE_BLOCKS.any? { |b| b.include? addr } | |
end | |
def safe_post(uri, body) | |
uri = URI.parse(uri) if uri.is_a? String | |
host = uri.host | |
addr = Resolv.getaddress(host) | |
validate_addr!(addr) | |
socket_class = StaticResolveTCPSocket.new(host => addr) | |
HTTP.post(uri, socket_class: socket_class, body: body) | |
end |
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