implemented secretKey parsing which is quite annoying. the length

has to be calculated since all length info is encrypted together with
the secret key.

23 files changed, 279 insertions, 132 deletions

diff --git a/lib/fpg/_preload.rb b/lib/fpg/_preload.rb
index ab676ef..e8cb784 100644
--- a/lib/fpg/_preload.rb
+++ b/lib/fpg/_preload.rb
@@ -1,7 +1,3 @@
 module FPG
   require 'bindata'
-  module Algos
-    class Algo < BinData::Record ; end
-    class Rsa < Algo ; end
-  end
 end
diff --git a/lib/fpg/algos/_symmetric.rb b/lib/fpg/algos/_symmetric.rb
new file mode 100644
index 0000000..acd9a13
--- /dev/null
+++ b/lib/fpg/algos/_symmetric.rb
@@ -0,0 +1,7 @@
+module FPG
+  module Algos
+    class Symmetric
+      include TaggedSubclasses
+    end
+  end
+end
diff --git a/lib/fpg/algos/asymmetric.rb b/lib/fpg/algos/asymmetric.rb
new file mode 100644
index 0000000..4daa794
--- /dev/null
+++ b/lib/fpg/algos/asymmetric.rb
@@ -0,0 +1,7 @@
+module FPG
+  module Algos
+    class Asymmetric
+      include TaggedSubclasses
+    end
+  end
+end
diff --git a/lib/fpg/algos/cast5.rb b/lib/fpg/algos/cast5.rb
new file mode 100644
index 0000000..d07712f
--- /dev/null
+++ b/lib/fpg/algos/cast5.rb
@@ -0,0 +1,12 @@
+module FPG
+  module Algos
+    class Cast5 < Symmetric
+      def block_size
+        8
+      end
+      def self.tag
+        3
+      end
+    end
+  end
+end
diff --git a/lib/fpg/algos/rsa.rb b/lib/fpg/algos/rsa.rb
new file mode 100644
index 0000000..49131d0
--- /dev/null
+++ b/lib/fpg/algos/rsa.rb
@@ -0,0 +1,9 @@
+module FPG
+  module Algos
+    class Rsa < Asymmetric
+      def self.tag
+        1
+      end
+    end
+  end
+end
diff --git a/lib/fpg/fields/key_id.rb b/lib/fpg/fields/key_id.rb
new file mode 100644
index 0000000..66bb4a5
--- /dev/null
+++ b/lib/fpg/fields/key_id.rb
@@ -0,0 +1,8 @@
+module FPG
+  module Fields
+    class KeyId < BinData::Record
+      endian  :big
+      uint64  :id
+    end
+  end
+end
diff --git a/lib/fpg/fields/packet_header.rb b/lib/fpg/fields/packet_header.rb
new file mode 100644
index 0000000..bf0dd17
--- /dev/null
+++ b/lib/fpg/fields/packet_header.rb
@@ -0,0 +1,92 @@
+module FPG
+  module Parse
+    class PacketHeader < BinData::BasePrimitive
+      def read_and_return_value(io)
+        @io = io
+        header = io.readbytes(1).unpack("C1")[0]
+        parse_id(header)
+        parse_header(header)
+        {:packet_size=>@byte_size,:packet_num=>@id,:header_size=>@header_size}
+      end
+      def sensible_default
+        0
+      end
+      def value_to_binary_string(value)
+        #Dummy implementation to calculate the size
+        return ".." if value[:packet_size] < 192
+        return "..." if value[:packet_size] < 8383
+        return "....." if value[:packet_size] < 4294967295
+        ".."
+      end
+
+      private
+     
+      def parse_header(header)
+        @byte_size = packet_size(header)
+        @byte_size += strip_partials if partial_length?
+      end
+      def parse_id(byte)
+        raise "this is not a valid packet header" unless byte>>7 == 1
+        if new_packet?(byte)
+          @id = byte-(1<<7)-(1<<6)
+        else
+          @id = (byte-(1<<7))>>2
+        end
+      end
+      def strip_partials
+          package_start = @io.raw_io.pos
+          start = package_start + @byte_size
+          partial_size = 0
+
+          while partial_length? do
+            @io.raw_io.pos= start+partial_size
+
+            size = new_packet_size
+            partial_size += size[:s]
+            
+            #remove the header packets from the stream => subclasses wont have to worry abouth this
+            @io.raw_io.zap(size[:h])
+          end
+          @io.raw_io.pos= package_start
+          partial_size
+      end
+      def partial_length?
+        @partial_length
+      end
+      def packet_size(header)
+        if new_packet?(header)
+          size = new_packet_size
+          @header_size = size[:h]+1
+          size[:s]
+        else
+          tag = old_size_tag(header)
+          @header_size = [2,3,5][tag]
+          old_packet_size(tag)
+        end
+      end
+      def new_packet_size
+        @partial_length= false
+        first = @io.readbytes(1).unpack("C1")[0]
+        return { :s => first, :h => 1 } if first < 192
+        return { :s => (((first-192)<<8)+@io.readbytes(1).unpack("C1")[0]+192), :h => 2 } if first < 224
+        return { :s => ((first+@io.readbytes(3)).unpack("N")[0]), :h => 4 } if first == 255
+        @partial_length= true
+        return { :s => (1<<(first&0x1f)), :h => 1 }
+      end
+      def old_packet_size(tag)
+        return @io.readbytes(1).unpack("C1")[0] if tag == 0
+        return @io.readbytes(2).unpack("n")[0] if tag == 1
+        return @io.readbytes(4).unpack("N")[0] if tag == 2
+        #tag==3 => size is until eof
+        raise 'partial size for old packets not implemented'
+      end
+      def old_size_tag(header)
+        #size tag = two lowest bits
+        header & 3
+      end
+      def new_packet?(byte)
+        byte>>6 == 3
+      end
+    end
+  end
+end
diff --git a/lib/fpg/public_key_algos/rsa.rb b/lib/fpg/fields/rsa.rb
index 528e808..f2c7c25 100644
--- a/lib/fpg/public_key_algos/rsa.rb
+++ b/lib/fpg/fields/rsa.rb
@@ -1,12 +1,8 @@
 module FPG
-  module Algos
-    class Rsa < Algo
+  module Fields
+    class Rsa < BinData::Record
       multi_precision_integer :n
       multi_precision_integer :e
-      
-      def self.tag
-        1
-      end
     end
   end
 end
diff --git a/lib/fpg/fields/rsa_secret.rb b/lib/fpg/fields/rsa_secret.rb
new file mode 100644
index 0000000..9ecb175
--- /dev/null
+++ b/lib/fpg/fields/rsa_secret.rb
@@ -0,0 +1,10 @@
+module FPG
+  module Fields
+    class RsaSecret < BinData::Record
+      multi_precision_integer :d
+      multi_precision_integer :p
+      multi_precision_integer :q
+      multi_precision_integer :u
+    end
+  end
+end
diff --git a/lib/fpg/fields/rsa_session.rb b/lib/fpg/fields/rsa_session.rb
new file mode 100644
index 0000000..13397a4
--- /dev/null
+++ b/lib/fpg/fields/rsa_session.rb
@@ -0,0 +1,7 @@
+module FPG
+  module Fields
+    class RsaSession < BinData::Record
+      multi_precision_integer :session_key
+    end
+  end
+end
diff --git a/lib/fpg/fields/s2k_specifier.rb b/lib/fpg/fields/s2k_specifier.rb
new file mode 100644
index 0000000..68fb0e2
--- /dev/null
+++ b/lib/fpg/fields/s2k_specifier.rb
@@ -0,0 +1,12 @@
+module FPG
+  module Fields
+    class S2kSpecifier < BinData::Record
+      endian  :big
+      uint8   :id
+      uint8   :hash_algo
+      uint64  :salt,       :onlyif => lambda { id > 0 }
+      uint8   :iterations, :onlyif => lambda { id > 2 }
+
+    end
+  end
+end
diff --git a/lib/fpg/io/zappable_byte_stream.rb b/lib/fpg/io/zappable_byte_stream.rb
index 73ba0b6..5358602 100644
--- a/lib/fpg/io/zappable_byte_stream.rb
+++ b/lib/fpg/io/zappable_byte_stream.rb
@@ -39,8 +39,17 @@ module FPG
         io.pos= to_internal_pos(position)
       end
       def seek(n,wh)
-        raise 'only support relative positioning' unless wh == IO::SEEK_CUR
-        self.pos= @pos+n  
+        case wh
+        when IO::SEEK_CUR
+          self.pos= @pos+n
+        when IO::SEEK_END
+          io.seek(n,IO::SEEK_END)
+          @pos = io.pos - zapped.size + rewind_to_next_byte
+        when IO::SEEK_SET
+          self.pos= n
+        else
+          raise "positioning not supported #{wh}"
+        end
       end
 
       private
@@ -54,6 +63,14 @@ module FPG
       def skip_to_next_byte
         io.readbyte while zapped[io.pos]
       end
+      def rewind_to_next_byte
+        i = 0
+        while zapped[io.pos] do
+          io.seek(-1,IO::SEEK_CUR)
+          i += 1
+        end
+        i
+      end
     end
   end
 end
diff --git a/lib/fpg/packets/_packet.rb b/lib/fpg/packets/_packet.rb
index f1b93a7..7a8b09d 100644
--- a/lib/fpg/packets/_packet.rb
+++ b/lib/fpg/packets/_packet.rb
@@ -3,92 +3,17 @@ module FPG
     require 'bindata'
     class Packet < BinData::Record
       include TaggedSubclasses
-      
       endian  :big
-      
-      attr_accessor :byte_size, :stream, :partial_length
+      packet_header   :header
 
-      def parse_header
-        @byte_size = packet_size
-        @byte_size += strip_partials if partial_length?
-      end
-      def read(stream)
-        puts "parsing #{self.class}"
-        @stream = stream
-        parse_header
-        start = @stream.pos
-        puts "size is #{byte_size}"
-        super(@stream)
-        raise 'parsing failed. packet length does not match with parsed content' if start+byte_size != @stream.pos
-        puts "done"
-      end
-      def skip
-        stream.seek(byte_size,IO::SEEK_CUR)
-      end
-      def parse_content
-        fail "shoul be implemented by subclass #{self.class}"
-      end
-
-      private
-
-      def strip_partials
-          package_start = @stream.pos
-          start = package_start + @byte_size
-          partial_size = 0
-
-          @stream = ZappableByteStream.new(stream)
-
-          while partial_length? do
-            @stream.pos= start+partial_size
-
-            size = new_packet_size
-            partial_size += size[:s]
-            
-            #remove the header packets from the stream => subclasses wont have to worry abouth this
-            @stream.zap(size[:h])
-          end
-          @stream.pos= package_start
-          partial_size
-      end
-      def partial_length?
-        partial_length
-      end
-      def packet_size
-        header = stream.getbyte
-        if new_packet?(header)
-          new_packet_size()[:s]
-        else
-          tag = old_size_tag(header)
-          old_packet_size(tag)
-        end
-      end
-      def new_packet_size
-        @partial_length= false
-        first = stream.getbyte
-        return { :s => first, :h => 1 } if first < 192
-        return { :s => (((first-192)<<8)+stream.getbyte+192), :h => 2 } if first < 224
-        return { :s => ((first+stream.read(3)).unpack("N")[0]), :h => 4 } if first == 255
-        @partial_length= true
-        return { :s => (1<<(first&0x1f)), :h => 1 }
-      end
-      def old_packet_size(tag)
-        return stream.getbyte if tag == 0
-        return stream.read(2).unpack("n")[0] if tag == 1
-        return stream.read(4).unpack("N")[0] if tag == 2
-        #tag==3 => size is until eof
-        #TODO this seems a bit cumbersome
-        current_pos = stream.pos
-        stream.seek(0,IO::SEEK_END)
-        size = 1+stream.pos - current_pos
-        stream.pos= current_pos
-        return size
-      end
-      def old_size_tag(header)
-        #size tag = two lowest bits
-        header & 3
-      end
-      def new_packet?(byte)
-        byte>>6 == 3
+      def byte_size
+        header[:packet_size]
+      end
+      def read(io)
+        pos = io.pos
+        super
+        parse_offset = io.pos-pos-byte_size-header[:header_size]
+        raise "parse err #{self.class}: off by #{parse_offset} bytes" if parse_offset != 0
       end
     end
   end
diff --git a/lib/fpg/packets/key_material.rb b/lib/fpg/packets/key_material.rb
index 01fd983..4ba5f23 100644
--- a/lib/fpg/packets/key_material.rb
+++ b/lib/fpg/packets/key_material.rb
@@ -2,7 +2,10 @@ module FPG
   module Packets
     class KeyMaterial < Packet
       def algo
-        Algos::Algo.with_tag(pubkey_algo)
+        Algos::Asymmetric.with_tag(pubkey_algo)
+      end
+      def self.tag
+        -1
       end
     end
   end
diff --git a/lib/fpg/packets/public_key_encrypted_session_key.rb b/lib/fpg/packets/public_key_encrypted_session_key.rb
index 1724d4b..38f50a7 100644
--- a/lib/fpg/packets/public_key_encrypted_session_key.rb
+++ b/lib/fpg/packets/public_key_encrypted_session_key.rb
@@ -1,8 +1,12 @@
 module FPG
   module Packets
-    class PublicKeyEncryptedSessionKey < Packet
-      attr_accessor :key_id, :encryption_algo, :session_key
-      string :skip_this, :read_length => :byte_size 
+    class PublicKeyEncryptedSessionKey < KeyMaterial
+      uint8   :version,     :check_value => lambda { value == 3 }
+      key_id  :key_id
+      uint8   :pubkey_algo
+      choice  :key_material, :selection => :pubkey_algo do
+        rsa_session   1
+      end
       def self.tag
         1
       end
diff --git a/lib/fpg/packets/secret_key.rb b/lib/fpg/packets/secret_key.rb
index fa9a599..c83a67b 100644
--- a/lib/fpg/packets/secret_key.rb
+++ b/lib/fpg/packets/secret_key.rb
@@ -1,7 +1,41 @@
 module FPG
   module Packets
-    class SecretKey < KeyMaterial
-      string :skip_this, :read_length => :byte_size 
+    class SecretKey < PublicKey
+      uint8         :s2k
+      uint8         :s2k_al,          :onlyif => :s2k_specifier_given?
+      s2k_specifier :s2k_specifier,   :onlyif => :s2k_specifier_given?
+      string        :iv,              :read_length => lambda { s2k_algo.block_size }, 
+                                      :onlyif => :is_encrypted?
+      choice  :secret_key_material,   :onlyif => :is_not_encrypted?, :selection => :pubkey_algo do
+        rsa_secret  1
+      end
+      string        :encrypted_secret_key_material,  :read_length => :secret_key_bytes,
+                                                     :onlyif      => :is_encrypted?
+      uint16        :checksum,  :onlyif => lambda{ ! long_checksum? }
+      uint160       :lchecksum,  :onlyif => :long_checksum?
+
+      def secret_key_bytes
+        header[:header_size] + byte_size - (encrypted_secret_key_material.offset) - checksum_size
+      end
+      def checksum_size
+        (long_checksum? ? 20 : 2)
+      end 
+      def s2k_algo
+        @s2k_algo ||= Algos::Symmetric.with_tag( s2k_specifier_given? ? s2k_al : s2k )
+      end
+      def s2k_specifier_given?
+        s2k >= 254
+      end
+      def is_encrypted?
+        s2k > 0
+      end
+      def is_not_encrypted?
+        ! is_encrypted?
+      end
+      def long_checksum?
+        s2k == 254
+      end
+
       def self.tag
         5
       end
diff --git a/lib/fpg/parse/parser.rb b/lib/fpg/parse/parser.rb
index 627eeb1..82d6322 100644
--- a/lib/fpg/parse/parser.rb
+++ b/lib/fpg/parse/parser.rb
@@ -1,8 +1,9 @@
 module FPG
   module Parse
     class Parser
-      def self.parse( stream )
+      def self.parse( aStream )
         packets = []
+        stream = ZappableByteStream.new(aStream)
         until stream.eof? do
           packets << parse_packet(stream)
           #rescue Exception => e
@@ -14,9 +15,16 @@ module FPG
       def self.parse_packet(stream)
         num = packet_number(stream.getbyte)
         stream.seek(-1,IO::SEEK_CUR)
-        p = Packets::Packet.with_tag(num)
-        p.read(stream)
-        p
+        packet = Packets::Packet.with_tag(num)
+        if packet.is_a? SecretKey then
+          puts
+          BinData::trace_reading do
+              packet.read(stream)
+          end
+        else
+          packet.read(stream)
+        end
+        packet
       end
       def self.packet_number(byte)
         raise "this is not a valid packet header" unless byte>>7 == 1
diff --git a/lib/fpg/public_key_algos/algo.rb b/lib/fpg/public_key_algos/algo.rb
deleted file mode 100644
index ec0954b..0000000
--- a/lib/fpg/public_key_algos/algo.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-module FPG
-  module Algos
-    class Algo < BinData::Record
-      include TaggedSubclasses
-      endian :big
-      attr_accessor :key_material
-    end
-  end
-end
diff --git a/lib/fpg/public_key_algos/rsa_encryption_only.rb b/lib/fpg/public_key_algos/rsa_encryption_only.rb
deleted file mode 100644
index fd8df6e..0000000
--- a/lib/fpg/public_key_algos/rsa_encryption_only.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-module FPG
-  module Algos
-    class RsaEncryptionOnly < Rsa
-    end
-  end
-end
diff --git a/lib/fpg/public_key_algos/rsa_sign_only.rb b/lib/fpg/public_key_algos/rsa_sign_only.rb
deleted file mode 100644
index 6e3f71b..0000000
--- a/lib/fpg/public_key_algos/rsa_sign_only.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-module FPG
-  module Algos
-    class RsaSignOnly < Rsa
-    end
-  end
-end
diff --git a/spec/.public_key_spec.rb.swp b/spec/.public_key_spec.rb.swp
deleted file mode 100644
index 9af39e1..0000000
--- a/spec/.public_key_spec.rb.swp
+++ /dev/null
diff --git a/spec/packet_parsing_spec.rb b/spec/packet_parsing_spec.rb
index d4949fa..376de22 100644
--- a/spec/packet_parsing_spec.rb
+++ b/spec/packet_parsing_spec.rb
@@ -21,11 +21,11 @@ describe Parser do
     parsed.any?{|packet| packet.is_a? PublicSubkey}.should be_true
   end
   it "should find all the packets in a secretkey" do
-#    parsed = Parser.parse(@binary_sec)
-#    parsed.any?{|packet| packet.is_a? Signature}.should be_true
-#    parsed.any?{|packet| packet.is_a? UserId}.should be_true
-#    parsed.any?{|packet| packet.is_a? SecretSubkey}.should be_true
-#    parsed.any?{|packet| packet.is_a? SecretKey}.should be_true
+    parsed = Parser.parse(@binary_sec)
+    parsed.any?{|packet| packet.is_a? Signature}.should be_true
+    parsed.any?{|packet| packet.is_a? UserId}.should be_true
+    parsed.any?{|packet| packet.is_a? SecretSubkey}.should be_true
+    parsed.any?{|packet| packet.is_a? SecretKey}.should be_true
   end
   it "should find all the packets in an encrypted message" do
     parsed = Parser.parse(@msg_enc)
diff --git a/spec/pk_encrypted_session_key_spec.rb b/spec/pk_encrypted_session_key_spec.rb
new file mode 100644
index 0000000..f3ebf13
--- /dev/null
+++ b/spec/pk_encrypted_session_key_spec.rb
@@ -0,0 +1,21 @@
+require File.join(File.dirname(__FILE__), %w[spec_helper])
+
+require 'stringio'
+
+include FPG::Parse
+include FPG::Packets
+include FPG::Algos
+
+describe PublicKeyEncryptedSessionKey do
+  before(:each) do
+   @msg_enc = File.open "spec/fixtures/messages/1_enc.gpg", 'rb'
+  end
+
+  it "should find all the packets in an encrypted message" do
+    parsed = Parser.parse(@msg_enc)
+    sk = parsed.select{|packet| packet.is_a? PublicKeyEncryptedSessionKey}.first
+    sk.algo.is_a?(Rsa).should be_true
+    sk.key_id.id.should == 0x8AC9A89E54DBDCF0
+  end
+end
+