tried to implement s2k. but ruby is tooo slow!HEADmaster

i guess the next thing will be to write a wrapper for libgcrypt

8 files changed, 74 insertions, 11 deletions

diff --git a/lib/fpg/algos/cast5.rb b/lib/fpg/algos/cast5.rb
index d07712f..58a0c87 100644
--- a/lib/fpg/algos/cast5.rb
+++ b/lib/fpg/algos/cast5.rb
@@ -4,6 +4,9 @@ module FPG
       def block_size
         8
       end
+      def key_size
+        128
+      end
       def self.tag
         3
       end
diff --git a/lib/fpg/algos/hash.rb b/lib/fpg/algos/hash.rb
index 1388124..a954818 100644
--- a/lib/fpg/algos/hash.rb
+++ b/lib/fpg/algos/hash.rb
@@ -1,6 +1,7 @@
 module FPG
   module Algos
     class Hash
+      require 'forwardable'
       include TaggedSubclasses
     end
   end
diff --git a/lib/fpg/algos/sha1.rb b/lib/fpg/algos/sha1.rb
index a47ce87..113f43d 100644
--- a/lib/fpg/algos/sha1.rb
+++ b/lib/fpg/algos/sha1.rb
@@ -1,6 +1,16 @@
 module FPG
   module Algos
     class Sha1 < Hash
+      require 'digest/sha1'
+      
+      extend Forwardable
+      def_delegator :@digest, :digest, :digest
+      def_delegator :@digest, :digest_length, :digest_length
+
+      def initialize
+        @digest = Digest::SHA1.new
+      end
+
       def self.tag
         2
       end
diff --git a/lib/fpg/fields/rsa_secret.rb b/lib/fpg/fields/rsa_secret.rb
index 9ecb175..75114e4 100644
--- a/lib/fpg/fields/rsa_secret.rb
+++ b/lib/fpg/fields/rsa_secret.rb
@@ -5,6 +5,9 @@ module FPG
       multi_precision_integer :p
       multi_precision_integer :q
       multi_precision_integer :u
+      def empty?
+        d.val.empty?
+      end
     end
   end
 end
diff --git a/lib/fpg/fields/s2k_specifier.rb b/lib/fpg/fields/s2k_specifier.rb
index 9b3a00c..8740568 100644
--- a/lib/fpg/fields/s2k_specifier.rb
+++ b/lib/fpg/fields/s2k_specifier.rb
@@ -4,12 +4,46 @@ module FPG
       endian  :big
       uint8   :id
       uint8   :h_algo
-      uint64  :salt,       :onlyif => lambda { id > 0 }
-      uint8   :iterations, :onlyif => lambda { id > 2 }
+      string  :salt,     :onlyif => lambda { id > 0 }, :read_length => 8
+      uint8   :octet_ct, :onlyif => lambda { id > 2 }
 
+      def octet_count
+        (16+(octet_ct&15))<<((octet_ct>>4)+6)
+      end
       def hash_algo
         Algos::Hash.with_tag(h_algo)
       end
+      def get_key(passphrase, key_length)
+        if id == 0 then
+          digest(passphrase, key_length)
+        elsif id == 1 then
+          digest(salt+passphrase, key_length)
+        elsif id == 3 then
+          pass = salt+passphrase
+          hashed = 0
+          while hashed < octet_count do
+            pass = digest(pass, key_length)
+            hashed += pass.length
+          end
+          pass
+        else
+          fail "#{id}"
+        end
+      end
+      def digest( passphrase, key_length )
+        if hash_algo.digest_length >= key_length then
+          hash_algo.digest( passphrase )[0..(key_length-hash_algo.digest_length)]
+        else
+          instances = (key_length / hash_algo.digest_length)
+          res = ""
+          (1..instances).each do |i|
+            preload = ""
+            i.times { preload << "\0" }
+            res << hash_algo.digest( preload+passphrase )
+          end
+          res[0..(key_length-(hash_algo.digest_length*instances))]
+        end
+      end
     end
   end
 end
diff --git a/lib/fpg/packets/secret_key.rb b/lib/fpg/packets/secret_key.rb
index 16d834f..61f8a6d 100644
--- a/lib/fpg/packets/secret_key.rb
+++ b/lib/fpg/packets/secret_key.rb
@@ -18,7 +18,15 @@ module FPG
       def hash_algo
         self.s2k_specifier.hash_algo
       end
-      
+      def open!
+        return unless secret_key_material.empty?
+        key = get_key("test")
+        raw_key = s2k_algo.decrypt(encrypted_secret_key_material,key)
+      end
+      def get_key(passphrase)
+        return Digest::MD5.digest(passphrase) unless s2k_specifier_given?
+        s2k_specifier.get_key(passphrase,s2k_algo.key_size)
+      end
       def s2k_specifier_given?
         s2k >= 254
       end
diff --git a/lib/fpg/parse/parser.rb b/lib/fpg/parse/parser.rb
index 76ba23e..5aed1e5 100644
--- a/lib/fpg/parse/parser.rb
+++ b/lib/fpg/parse/parser.rb
@@ -16,14 +16,14 @@ module FPG
         num = packet_number(stream.getbyte)
         stream.seek(-1,IO::SEEK_CUR)
         packet = Packets::Packet.with_tag(num)
-        if packet.is_a? Signature then
-          puts
-          BinData::trace_reading do
-              packet.read(stream)
-          end
-        else
+#        if packet.is_a? Signature then
+#          puts
+#          BinData::trace_reading do
+#              packet.read(stream)
+#          end
+#        else
           packet.read(stream)
-        end
+#        end
         packet
       end
       def self.packet_number(byte)
diff --git a/spec/secret_key_spec.rb b/spec/secret_key_spec.rb
index 4268829..fd778f2 100644
--- a/spec/secret_key_spec.rb
+++ b/spec/secret_key_spec.rb
@@ -17,7 +17,11 @@ describe SecretKey do
     pk.algo.is_a?( Rsa ).should be_true
     pk.key_material.n.bit_len.should == 4096
     pk.hash_algo.is_a?( Sha1 ).should be_true
-
+  end
+  it "should be able to open a key" do
+    parsed = Parser.parse(@binary_sec)
+    pk = parsed.select{|packet| packet.is_a? SecretKey}.first
+    puts pk.open!
   end
 end