#!/usr/bin/perl -w -T
# pem2openpgp: take a PEM-encoded RSA private-key on standard input, a
-# User ID as the first argument, and generate an OpenPGP certificate
-# from it.
+# User ID as the first argument, and generate an OpenPGP secret key
+# and certificate from it.
+
+# WARNING: the secret key material *will* appear on stdout (albeit in
+# OpenPGP form) -- if you redirect stdout to a file, make sure the
+# permissions on that file are appropriately locked down!
# Usage:
# hostname_long() from Sys::Hostname::Long ?
+my $old_format_packet_lengths = { one => 0,
+ two => 1,
+ four => 2,
+ indeterminate => 3,
+};
# see RFC 4880 section 9.1 (ignoring deprecated algorithms for now)
my $asym_algos = { rsa => 1,
# produce it, we need to produce key/value-swapped lookup tables as well.
+########### Math/Utility Functions ##############
+
+
+# see the bottom of page 43 of RFC 4880
+sub simple_checksum {
+ my $bytes = shift;
+
+ return unpack("%32W*",$bytes) % 65536;
+}
+
+# calculate the multiplicative inverse of a mod b this is euclid's
+# extended algorithm. For more information see:
+# http://en.wikipedia.org/wiki/Extended_Euclidean_algorithm the
+# arguments here should be Crypt::OpenSSL::Bignum objects. $a should
+# be the larger of the two values, and the two values should be
+# coprime.
+
+sub modular_multi_inverse {
+ my $a = shift;
+ my $b = shift;
+
+
+ my $origdivisor = $b->copy();
+
+ my $ctx = Crypt::OpenSSL::Bignum::CTX->new();
+ my $x = Crypt::OpenSSL::Bignum->zero();
+ my $y = Crypt::OpenSSL::Bignum->one();
+ my $lastx = Crypt::OpenSSL::Bignum->one();
+ my $lasty = Crypt::OpenSSL::Bignum->zero();
+
+ my $finalquotient;
+ my $finalremainder;
+
+ while (! $b->is_zero()) {
+ my ($quotient, $remainder) = $a->div($b, $ctx);
+
+ $a = $b;
+ $b = $remainder;
+
+ my $temp = $x;
+ $x = $lastx->sub($quotient->mul($x, $ctx));
+ $lastx = $temp;
+
+ $temp = $y;
+ $y = $lasty->sub($quotient->mul($y, $ctx));
+ $lasty = $temp;
+ }
+
+ if (!$a->is_one()) {
+ die "did this math wrong.\n";
+ }
+
+ # let's make sure that we return a positive value because RFC 4880,
+ # section 3.2 only allows unsigned values:
+
+ ($finalquotient, $finalremainder) = $lastx->add($origdivisor)->div($origdivisor, $ctx);
+
+ return $finalremainder;
+}
+
+
+############ OpenPGP formatting functions ############
+
# make an old-style packet out of the given packet type and body.
# old-style (see RFC 4880 section 4.2)
sub make_packet {
my $type = shift;
my $body = shift;
+ my $options = shift;
my $len = length($body);
+ my $pseudolen = $len;
+
+ # if the caller wants to use at least N octets of packet length,
+ # pretend that we're using that many.
+ if (defined $options && defined $options->{'packet_length'}) {
+ $pseudolen = 2**($options->{'packet_length'} * 8) - 1;
+ }
+ if ($pseudolen < $len) {
+ $pseudolen = $len;
+ }
my $lenbytes;
my $lencode;
- if ($len < 2**8) {
- $lenbytes = 0;
+ if ($pseudolen < 2**8) {
+ $lenbytes = $old_format_packet_lengths->{one};
$lencode = 'C';
- } elsif ($len < 2**16) {
- $lenbytes = 1;
+ } elsif ($pseudolen < 2**16) {
+ $lenbytes = $old_format_packet_lengths->{two};
$lencode = 'n';
- } elsif ($len < 2**31) {
+ } elsif ($pseudolen < 2**31) {
## not testing against full 32 bits because i don't want to deal
## with potential overflow.
- $lenbytes = 2;
+ $lenbytes = $old_format_packet_lengths->{four};
$lencode = 'N';
} else {
## what the hell do we do here?
- $lenbytes = 3;
+ $lenbytes = $old_format_packet_lengths->{indeterminate};
$lencode = '';
}
return pack('n', $mpilen).$val;
}
-# see the bottom of page 43 of RFC 4880
-sub simple_checksum {
- my $bytes = shift;
-
- return unpack("%32W*",$bytes) % 65536;
-}
-
# FIXME: genericize these to accept either RSA or DSA keys:
sub make_rsa_pub_key_body {
my $key = shift;
mpi_pack($e);
}
-# calculate the multiplicative inverse of a mod b this is euclid's
-# extended algorithm. For more information see:
-# http://en.wikipedia.org/wiki/Extended_Euclidean_algorithm the
-# arguments here should be Crypt::OpenSSL::Bignum objects. $a should
-# be the larger of the two values, and the two values should be
-# coprime.
-
-sub modular_multi_inverse {
- my $a = shift;
- my $b = shift;
-
- my $ctx = Crypt::OpenSSL::Bignum::CTX->new();
- my $x = Crypt::OpenSSL::Bignum->zero();
- my $y = Crypt::OpenSSL::Bignum->one();
- my $lastx = Crypt::OpenSSL::Bignum->one();
- my $lasty = Crypt::OpenSSL::Bignum->zero();
-
- while (! $b->is_zero()) {
- my ($quotient, $remainder) = $a->div($b, $ctx);
-
- $a = $b;
- $b = $remainder;
-
- my $temp = $x;
- $x = $lastx->sub($quotient->mul($x, $ctx));
- $lastx = $temp;
-
- $temp = $y;
- $y = $lasty->sub($quotient->mul($y, $ctx));
- $lasty = $temp;
- }
-
- if (!$a->is_one()) {
- die "did this math wrong.\n";
- }
-
- return $lastx;
-}
-
sub make_rsa_sec_key_body {
my $key = shift;
my $timestamp = shift;
# we're not using $a and $b, but we need them to get to $c.
my ($n, $e, $d, $p, $q) = $key->get_key_parameters();
+ my $c3 = modular_multi_inverse($p, $q);
+
my $secret_material = mpi_pack($d).
mpi_pack($p).
mpi_pack($q).
- mpi_pack(modular_multi_inverse($p, $q));
+ mpi_pack($c3);
# according to Crypt::OpenSSL::RSA, the closest value we can get out
# of get_key_parameters is 1/q mod p; but according to sec 5.5.3 of
return Digest::SHA1::sha1(pack('Cn', 0x99, length($rsabody)).$rsabody);
}
-# we're just not dealing with newline business right now. slurp in
-# the whole file.
-undef $/;
-my $buf = <STDIN>;
-
-my $rsa = Crypt::OpenSSL::RSA->new_private_key($buf);
+my $rsa;
+if (defined $ENV{PEM2OPENPGP_NEWKEY}) {
+ $rsa = Crypt::OpenSSL::RSA->generate_key($ENV{PEM2OPENPGP_NEWKEY});
+} else {
+ # we're just not dealing with newline business right now. slurp in
+ # the whole file.
+ undef $/;
+ $rsa = Crypt::OpenSSL::RSA->new_private_key(<STDIN>);
+}
$rsa->use_sha1_hash();
# FIXME: i'm worried about generating a bazillion new OpenPGP
# certificates from the same key, which could easily happen if you run
-# this script more than once against the same key. How can we prevent
-# this?
-
-# could an environment variable (if set) override the current time?
-my $timestamp = time();
+# this script more than once against the same key (because the
+# timestamps will differ). How can we prevent this?
+
+# this environment variable (if set) overrides the current time, to
+# be able to create a standard key? If we read the key from a file
+# instead of stdin, should we use the creation time on the file?
+my $timestamp = 0;
+if (defined $ENV{PEM2OPENPGP_TIMESTAMP}) {
+ $timestamp = ($ENV{PEM2OPENPGP_TIMESTAMP} + 0);
+} else {
+ $timestamp = time();
+}
my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp);
-# FIXME: HARDCODED: what if someone wants to select a different set of
-# usage flags? For now, we do only authentication.
-my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $usage_flags->{authenticate});
+my $flags = 0;
+if (! defined $ENV{PEM2OPENPGP_USAGE_FLAGS}) {
+ $flags = $usage_flags->{certify};
+} else {
+ my @ff = split(",", $ENV{PEM2OPENPGP_USAGE_FLAGS});
+ foreach my $f (@ff) {
+ if (! defined $usage_flags->{$f}) {
+ die "No such flag $f";
+ }
+ $flags |= $usage_flags->{$f};
+ }
+}
+my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $flags);
-# FIXME: HARDCODED: how should we determine how far off to set the
-# expiration date? default is to expire in 2 days, which is insanely
-# short (but good for testing).
-my $expires_in = 86400*2;
-my $expiration_packet = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
+
+# how should we determine how far off to set the expiration date?
+# default is no expiration. Specify the timestamp in seconds from the
+# key creation.
+my $expiration_packet = '';
+if (defined $ENV{PEM2OPENPGP_EXPIRATION}) {
+ my $expires_in = $ENV{PEM2OPENPGP_EXPIRATION} + 0;
+ $expiration_packet = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
+}
# prefer AES-256, AES-192, AES-128, CAST5, 3DES:
my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
my $seckey = make_rsa_sec_key_body($rsa, $timestamp);
-my $key_data = make_packet($packet_types->{pubkey}, $pubkey);
+# this is for signing. it needs to be an old-style header with a
+# 2-packet octet count.
+
+my $key_data = make_packet($packet_types->{pubkey}, $pubkey, {'packet_length'=>2});
# take the last 8 bytes of the fingerprint as the keyid:
my $keyid = substr(fingerprint($rsa, $timestamp), 20 - 8, 8);
my $data_hash = Digest::SHA1::sha1_hex($datatosign);
-
my $issuer_packet = pack('CCa8', 9, $subpacket_types->{issuer}, $keyid);
my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign));
projects / monkeysphere.git / blobdiff