pem2openpgp now accepts a choice of User ID on stdin.

[monkeysphere.git] / src / keytrans / pem2openpgp

diff --git a/src/keytrans/pem2openpgp b/src/keytrans/pem2openpgp
index 38baa959d93f433c33b50e29676025792f0a94d3..3fdc469ac95df1c07fcd694fc4a5d3a0877e743f 100755 (executable)
--- a/src/keytrans/pem2openpgp
+++ b/src/keytrans/pem2openpgp
@@ -20,6 +20,12 @@ use Crypt::OpenSSL::Bignum;
 use Digest::SHA1;
 use MIME::Base64;
 
+## make sure all length() and substr() calls use bytes only:
+use bytes;
+
+my $uid = shift;
+
+# FIXME: fail if there is no given user ID.
 
 # make an old-style packet out of the given packet type and body.
 # old-style  (see RFC 4880 section 4.2)
@@ -27,7 +33,6 @@ sub make_packet {
   my $type = shift;
   my $body = shift;
 
-# FIXME: yet another length():
   my $len = length($body);
 
   my $lenbytes;
@@ -55,22 +60,47 @@ sub make_packet {
 }
 
 
-# takes a Crypt::OpenSSL::Bignum
+# takes a Crypt::OpenSSL::Bignum, returns it formatted as OpenPGP MPI
+# (RFC 4880 section 3.2)
 sub mpi_pack {
   my $num = shift;
 
-  my $hex = $num->to_hex();
-
-  my $mpilen = length($hex)*4;
+  my $val = $num->to_bin();
+  my $mpilen = length($val)*8;
 
-# this is a kludgy way to get the number of bits in the first byte:
-  my $bitsinfirstbyte = length(sprintf("%b", hex(substr $hex, 0, 2)));
+# this is a kludgy way to get the number of significant bits in the
+# first byte:
+  my $bitsinfirstbyte = length(sprintf("%b", ord($val)));
 
   $mpilen -= (8 - $bitsinfirstbyte);
 
-  return pack('n', $mpilen).$num->to_bin();
+  return pack('n', $mpilen).$val;
 }
 
+# FIXME: genericize this to accept either RSA or DSA keys:
+sub make_rsa_key_body {
+  my $key = shift;
+  my $timestamp = shift;
+
+  my ($n, $e) = $key->get_key_parameters();
+
+  return
+    pack('CN', 4, $timestamp).
+      pack('C', 1). # RSA
+       mpi_pack($n).
+         mpi_pack($e);
+
+}
+
+# expects an RSA key (public or private) and a timestamp
+sub fingerprint {
+  my $key = shift;
+  my $timestamp = shift;
+
+  my $rsabody = make_rsa_key_body($key, $timestamp);
+
+  return Digest::SHA1::sha1_hex(pack('Cn', 0x99, length($rsabody)).$rsabody);
+}
 
 my $holdTerminator = $/;
 undef $/;
@@ -86,10 +116,6 @@ if (! $rsa->check_key()) {
   die "key does not check";
 }
 
-my $uid = 'fake key (do not use) <test@example.org>';
-
-
-
 my $version = pack('C', 4);
 # strong assertion of identity:
 my $sigtype = pack('C', 0x13);
@@ -130,7 +156,7 @@ my $features = pack('CCC', 2, 30, 1);
 # keyserver preference: only owner modify (???):
 my $keyserver_pref = pack('CCC', 2, 23, 0x80);
 
-my $subpackets_to_be_hashed = 
+my $subpackets_to_be_hashed =
   $creation_time_packet.
   $usage_packet.
   $expiration_packet.
@@ -140,7 +166,6 @@ my $subpackets_to_be_hashed =
   $features.
   $keyserver_pref;
 
-#FIXME: what's the right way to get length()?
 my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
 
 my $sig_data_to_be_hashed =
@@ -151,22 +176,13 @@ my $sig_data_to_be_hashed =
   $subpacket_octets.
   $subpackets_to_be_hashed;
 
-
-my ($n, $e, $d, $p, $q) = $rsa->get_key_parameters();
-
-
-my $pubkey =
-  pack('CN', 4, $timestamp).
-  $pubkey_algo.
-  mpi_pack($n).
-  mpi_pack($e);
+my $pubkey = make_rsa_key_body($rsa, $timestamp);
 
 #open(KEYFILE, "</home/wt215/gpg-test/key-data");
 my $key_data = make_packet(6, $pubkey);
 
-# FIXME: $keyid should be generated from the public key instead of
-# hardcoded:
-my $keyid = '5616d7cb02e69446';
+# take the last 16 characters of the fingerprint as the keyid:
+my $keyid = substr(fingerprint($rsa, $timestamp), 40 - 16, 16);
 
 # the v4 signature trailer is:
 
@@ -174,8 +190,6 @@ my $keyid = '5616d7cb02e69446';
 # signature data itself.
 my $trailer = pack('CCN', 4, 0xff, length($sig_data_to_be_hashed));
 
-# FIXME: length() is probably not right here either in the event that
-# the uid uses unicode.
 my $uid_data =
   pack('CN', 0xb4, length($uid)).
   $uid;
@@ -195,7 +209,6 @@ my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign));
 
 my $sig_body =
   $sig_data_to_be_hashed.
-# FIXME: another dubious length() call.
   pack('n', length($issuer_packet)).
   $issuer_packet.
   pack('n', hex(substr($data_hash, 0, 4))).