initial commit

7 files changed, 283 insertions, 0 deletions

diff --git a/lib/nickserver.rb b/lib/nickserver.rb
new file mode 100644
index 0000000..9ddc839
--- /dev/null
+++ b/lib/nickserver.rb
@@ -0,0 +1,10 @@
+
+require "nickserver/version"
+require "nickserver/config"
+
+require "nickserver/hkp/key_info"
+require "nickserver/hkp/fetch_key_info"
+require "nickserver/hkp/fetch_key"
+
+require "nickserver/server"
+
diff --git a/lib/nickserver/config.rb b/lib/nickserver/config.rb
new file mode 100644
index 0000000..d47fc68
--- /dev/null
+++ b/lib/nickserver/config.rb
@@ -0,0 +1,14 @@
+module Nickserver
+  class Config
+    class << self
+      attr_accessor :sks_url
+      attr_accessor :port
+    end
+  end
+
+  #
+  # set reasonable defaults
+  #
+  Config.sks_url = 'https://hkps.pool.sks-keyservers.net:/pks/lookup'
+  Config.port = 6425 # aka "NICK"
+end
diff --git a/lib/nickserver/hkp/fetch_key.rb b/lib/nickserver/hkp/fetch_key.rb
new file mode 100644
index 0000000..c72ee11
--- /dev/null
+++ b/lib/nickserver/hkp/fetch_key.rb
@@ -0,0 +1,51 @@
+require 'em-http'
+
+module Nickserver; module HKP
+
+  class FetchKey
+    include EM::Deferrable
+
+    def get(uid)
+      FetchKeyInfo.new.search(uid).callback {|key_info_list|
+        best = pick_best_key(key_info_list)
+        get_key_by_fingerprint(best.keyid) {|key|
+          self.succeed key
+        }
+      }.errback {|msg|
+        self.fail msg
+      }
+      self
+    end
+
+    #
+    # fetches ascii armored OpenPGP public key from the keyserver
+    #
+    def get_key_by_fingerprint(key_id)
+      params = {:op => 'get', :search => "0x" + key_id, :exact => 'on', :options => 'mr'}
+      http = EventMachine::HttpRequest.new(Config.sks_url).get(:query => params)
+      http.callback {
+        if http.response_header.status != 200
+          self.fail http.response_header.status #"Request failed with #{http.response_header.status}: #{http.response}"
+        else
+          yield http.response
+        end
+      }
+      http.errback {
+        self.fail http.error
+      }
+    end
+
+    protected
+
+    #
+    # for now, just pick the newest key.
+    #
+    # in the future, we should perhaps pick the newest key
+    # that is signed by the oldest key.
+    #
+    def pick_best_key(key_info_list)
+      key_info_list.sort {|a,b| a.creationdate <=> b.creationdate}.last
+    end
+  end
+
+end; end
\ No newline at end of file
diff --git a/lib/nickserver/hkp/fetch_key_info.rb b/lib/nickserver/hkp/fetch_key_info.rb
new file mode 100644
index 0000000..48ef48a
--- /dev/null
+++ b/lib/nickserver/hkp/fetch_key_info.rb
@@ -0,0 +1,66 @@
+require 'em-http'
+
+#
+# used to fetch an array of KeyInfo objects that match the given uid.
+#
+
+module Nickserver; module HKP
+  class FetchKeyInfo
+    include EM::Deferrable
+
+    # for this regexp to work, the source text must end in a trailing "\n",
+    # which the output of sks does.
+    MATCH_PUB_KEY = /(^pub:.+?\n(^uid:.+?\n)+)/m
+
+    def search(uid)
+      # in practice, exact=on seems to have no effect
+      params = {:op => 'vindex', :search => uid, :exact => 'on', :options => 'mr', :fingerprint => 'on'}
+      EventMachine::HttpRequest.new(Config.sks_url).get(:query => params).callback {|http|
+        if http.response_header.status != 200
+          self.fail http.response_header.status
+        else
+          self.succeed parse(uid, http.response)
+        end
+      }.errback {|http|
+        self.fail http.error
+      }
+      self
+    end
+
+    #
+    # input:
+    #  uid           -- uid to search for
+    #  vindex_result -- raw output from a vindex hkp query (machine readable)
+    #
+    # returns:
+    #   an array of eligible keys (as HKPKeyInfo objects) matching uid.
+    #
+    # keys are eliminated from eligibility for a number of reasons, including expiration,
+    # revocation, uid match, key length, and so on...
+    #
+    def parse(uid, vindex_result)
+      keys = []
+      now = Time.now
+      vindex_result.scan(MATCH_PUB_KEY).each do |match|
+        key_info = KeyInfo.new(match[0])
+        if key_info.uids.include?(uid)
+          if key_info.keylen <= 1024
+            #puts 'key length is too short'
+          elsif key_info.expired?
+            #puts 'ignoring expired key'
+          elsif key_info.revoked?
+            #puts 'ignoring revoked key'
+          elsif key_info.disabled?
+            #puts 'ignoring disabled key'
+          elsif key_info.expirationdate && key_info.expirationdate < now
+            #puts 'ignoring expired key'
+          else
+            keys << key_info
+          end
+        end
+      end
+      keys
+    end
+  end
+
+end; end
\ No newline at end of file
diff --git a/lib/nickserver/hkp/key_info.rb b/lib/nickserver/hkp/key_info.rb
new file mode 100644
index 0000000..adb75d8
--- /dev/null
+++ b/lib/nickserver/hkp/key_info.rb
@@ -0,0 +1,69 @@
+require 'cgi'
+
+#
+# Class to represent the key information result from a query to a key server
+# (but not the key itself).
+#
+# The initialize method parses the hkp 'machine readable' output.
+#
+# format definition of machine readable index output is here:
+# http://tools.ietf.org/html/draft-shaw-openpgp-hkp-00#section-5.2
+#
+module Nickserver; module HKP
+  class KeyInfo
+    attr_accessor :uids, :keyid, :algo, :keylen, :creationdate, :expirationdate, :flags
+
+    def initialize(hkp_record)
+      uid_lines = hkp_record.split("\n")
+      pub_line  = uid_lines.shift
+      @keyid, @algo, @keylen_s, @creationdate_s, @expirationdate_s, @flags = pub_line.split(':')[1..-1]
+      @uids = []
+      uid_lines.each do |uid_line|
+        uid, creationdate, expirationdate, flags = uid_line.split(':')[1..-1]
+        # for now, ignore the expirationdate and flags of uids. sks does return them anyway
+        @uids << CGI.unescape(uid.sub(/.*<(.+)>.*/, '\1'))
+      end
+    end
+
+    def keylen
+      @keylen ||= @keylen_s.to_i
+    end
+
+    def creationdate
+      @creationdate ||= begin
+        if @creationdate_s
+          Time.at(@creationdate_s.to_i)
+        end
+      end
+    end
+
+    def expirationdate
+      @expirationdate ||= begin
+        if @expirationdate_s
+          Time.at(@expirationdate_s.to_i)
+        end
+      end
+    end
+
+    def rsa?
+      @algo == "1"
+    end
+
+    def dsa?
+      @algo == "17"
+    end
+
+    def revoked?
+      @flags =~ /r/
+    end
+
+    def disabled?
+      @flags =~ /d/
+    end
+
+    def expired?
+      @flags =~ /e/
+    end
+  end
+
+end; end
diff --git a/lib/nickserver/server.rb b/lib/nickserver/server.rb
new file mode 100644
index 0000000..4201cef
--- /dev/null
+++ b/lib/nickserver/server.rb
@@ -0,0 +1,70 @@
+require 'eventmachine'
+require 'evma_httpserver'
+
+
+#
+# This is the main HTTP server that clients connect to in order to fetch keys
+#
+module Nickserver
+  class Server < EM::Connection
+    include EM::HttpServer
+
+    def post_init
+      super
+      no_environment_strings
+    end
+
+    def process_http_request
+      # the http request details are available via the following instance variables:
+      #   @http_protocol
+      #   @http_request_method
+      #   @http_cookie
+      #   @http_if_none_match
+      #   @http_content_type
+      #   @http_path_info
+      #   @http_request_uri
+      #   @http_query_string
+      #   @http_post_content
+      #   @http_headers
+      if @http_request_method == "GET"
+        if @http_path_info =~ /^\/key\//
+          send_key
+        else
+          send_error("malformed path: #{@http_path_info}")
+        end
+      else
+        send_error("only GET is supported")
+      end
+    end
+
+    private
+
+    def send_error(msg = "not supported")
+      send_response(:status => 500, :content => msg)
+    end
+
+    def send_key
+      uid = CGI.unescape @http_path_info.sub(/^\/key\/(.*)/, '\1')
+      get_key_from_uid(uid) do |key|
+        send_response(:content => key)
+      end
+    end
+
+    def send_response(opts = {})
+      options = {:status => 200, :content_type => 'text/plain', :content => ''}.merge(opts)
+      response = EM::DelegatedHttpResponse.new(self)
+      response.status = options[:status]
+      response.content_type options[:content_type]
+      response.content = options[:content]
+      response.send_response
+    end
+
+    def get_key_from_uid(uid)
+      Nickserver::HKP::FetchKey.new.get(uid).callback {|key|
+        yield key
+      }.errback {|status|
+        send_response(:status => status, :content => 'could not fetch key')
+      }
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/nickserver/version.rb b/lib/nickserver/version.rb
new file mode 100644
index 0000000..799ca6c
--- /dev/null
+++ b/lib/nickserver/version.rb
@@ -0,0 +1,3 @@
+module Nickserver
+  VERSION = "0.0.1"
+end