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trollwot/bruteforce_keyid

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#!/usr/bin/perl -T
# This is a modified version of keytrans. I'm using it specifically
# to brute force specific OpenPGP key IDs.
# Usage:
# bruteforce_keyid [user_id] [key_id]
# e.g.
# bruteforce_keyid "Name <email@host>" EFF00000
# keytrans: this is an RSA key translation utility; it is capable of
# transforming RSA keys (both public keys and secret keys) between
# several popular representations, including OpenPGP, PEM-encoded
# PKCS#1 DER, and OpenSSH-style public key lines.
# How it behaves depends on the name under which it is invoked. The
# two implementations currently are: pem2openpgp and openpgp2ssh.
# pem2openpgp: take a PEM-encoded RSA private-key on standard input, a
# 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:
# pem2openpgp 'ssh://'$(hostname -f) < /etc/ssh/ssh_host_rsa_key | gpg --import
# openpgp2ssh: take a stream of OpenPGP packets containing public or
# secret key material on standard input, and a Key ID (or fingerprint)
# as the first argument. Find the matching key in the input stream,
# and emit it on stdout in an OpenSSH-compatible format. If the input
# key is an OpenPGP public key (either primary or subkey), the output
# will be an OpenSSH single-line public key. If the input key is an
# OpenPGP secret key, the output will be a PEM-encoded RSA key.
# Example usage:
# gpg --export-secret-subkeys --export-options export-reset-subkey-passwd $KEYID | \
# openpgp2ssh $KEYID | ssh-add /dev/stdin
# Authors:
# Jameson Rollins <jrollins@finestructure.net>
# Daniel Kahn Gillmor <dkg@fifthhorseman.net>
# Started on: 2009-01-07 02:01:19-0500
# License: GPL v3 or later (we may need to adjust this given that this
# connects to OpenSSL via perl)
use strict;
use warnings;
use File::Basename;
use Crypt::OpenSSL::RSA;
use Crypt::OpenSSL::Bignum;
use Crypt::OpenSSL::Bignum::CTX;
use Digest::SHA;
use MIME::Base64;
use POSIX;
## make sure all length() and substr() calls use bytes only:
use bytes;
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,
elgamal => 16,
dsa => 17,
};
# see RFC 4880 section 9.2
my $ciphers = { plaintext => 0,
idea => 1,
tripledes => 2,
cast5 => 3,
blowfish => 4,
aes128 => 7,
aes192 => 8,
aes256 => 9,
twofish => 10,
};
# see RFC 4880 section 9.3
my $zips = { uncompressed => 0,
zip => 1,
zlib => 2,
bzip2 => 3,
};
# see RFC 4880 section 9.4
my $digests = { md5 => 1,
sha1 => 2,
ripemd160 => 3,
sha256 => 8,
sha384 => 9,
sha512 => 10,
sha224 => 11,
};
# see RFC 4880 section 5.2.3.21
my $usage_flags = { certify => 0x01,
sign => 0x02,
encrypt_comms => 0x04,
encrypt_storage => 0x08,
encrypt => 0x0c, ## both comms and storage
split => 0x10, # the private key is split via secret sharing
authenticate => 0x20,
shared => 0x80, # more than one person holds the entire private key
};
# see RFC 4880 section 4.3
my $packet_types = { pubkey_enc_session => 1,
sig => 2,
symkey_enc_session => 3,
onepass_sig => 4,
seckey => 5,
pubkey => 6,
sec_subkey => 7,
compressed_data => 8,
symenc_data => 9,
marker => 10,
literal => 11,
trust => 12,
uid => 13,
pub_subkey => 14,
uat => 17,
symenc_w_integrity => 18,
mdc => 19,
};
# see RFC 4880 section 5.2.1
my $sig_types = { binary_doc => 0x00,
text_doc => 0x01,
standalone => 0x02,
generic_certification => 0x10,
persona_certification => 0x11,
casual_certification => 0x12,
positive_certification => 0x13,
subkey_binding => 0x18,
primary_key_binding => 0x19,
key_signature => 0x1f,
key_revocation => 0x20,
subkey_revocation => 0x28,
certification_revocation => 0x30,
timestamp => 0x40,
thirdparty => 0x50,
};
# see RFC 4880 section 5.2.3.23
my $revocation_reasons = { no_reason_specified => 0,
key_superseded => 1,
key_compromised => 2,
key_retired => 3,
user_id_no_longer_valid => 32,
};
# see RFC 4880 section 5.2.3.1
my $subpacket_types = { sig_creation_time => 2,
sig_expiration_time => 3,
exportable => 4,
trust_sig => 5,
regex => 6,
revocable => 7,
key_expiration_time => 9,
preferred_cipher => 11,
revocation_key => 12,
issuer => 16,
notation => 20,
preferred_digest => 21,
preferred_compression => 22,
keyserver_prefs => 23,
preferred_keyserver => 24,
primary_uid => 25,
policy_uri => 26,
usage_flags => 27,
signers_uid => 28,
revocation_reason => 29,
features => 30,
signature_target => 31,
embedded_signature => 32,
};
# bitstring (see RFC 4880 section 5.2.3.24)
my $features = { mdc => 0x01
};
# bitstring (see RFC 4880 5.2.3.17)
my $keyserver_prefs = { nomodify => 0x80
};
###### end lookup tables ######
# FIXME: if we want to be able to interpret openpgp data as well as
# produce it, we need to produce key/value-swapped lookup tables as well.
########### Math/Utility Functions ##############
# see the bottom of page 44 of RFC 4880 (http://tools.ietf.org/html/rfc4880#page-44)
sub simple_checksum {
my $bytes = shift;
return unpack("%16C*",$bytes);
}
# calculate/print the fingerprint of an openssh-style keyblob:
sub sshfpr {
my $keyblob = shift;
use Digest::MD5;
return join(':', map({unpack("H*", $_)} split(//, Digest::MD5::md5($keyblob))));
}
# 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 $lencode;
if ($pseudolen < 2**8) {
$lenbytes = $old_format_packet_lengths->{one};
$lencode = 'C';
} elsif ($pseudolen < 2**16) {
$lenbytes = $old_format_packet_lengths->{two};
$lencode = 'n';
} elsif ($pseudolen < 2**31) {
## not testing against full 32 bits because i don't want to deal
## with potential overflow.
$lenbytes = $old_format_packet_lengths->{four};
$lencode = 'N';
} else {
## what the hell do we do here?
$lenbytes = $old_format_packet_lengths->{indeterminate};
$lencode = '';
}
return pack('C'.$lencode, 0x80 + ($type * 4) + $lenbytes, $len).
$body;
}
# takes a Crypt::OpenSSL::Bignum, returns it formatted as OpenPGP MPI
# (RFC 4880 section 3.2)
sub mpi_pack {
my $num = shift;
my $val = $num->to_bin();
my $mpilen = length($val)*8;
# 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', $mpilen).$val;
}
# takes a Crypt::OpenSSL::Bignum, returns an MPI packed in preparation
# for an OpenSSH-style public key format. see:
# http://marc.info/?l=openssh-unix-dev&m=121866301718839&w=2
sub openssh_mpi_pack {
my $num = shift;
my $val = $num->to_bin();
my $mpilen = length($val);
my $ret = pack('N', $mpilen);
# if the first bit of the leading byte is high, we should include a
# 0 byte:
if (ord($val) & 0x80) {
$ret = pack('NC', $mpilen+1, 0);
}
return $ret.$val;
}
sub openssh_pubkey_pack {
my $key = shift;
my ($modulus, $exponent) = $key->get_key_parameters();
return openssh_mpi_pack(Crypt::OpenSSL::Bignum->new_from_bin("ssh-rsa")).
openssh_mpi_pack($exponent).
openssh_mpi_pack($modulus);
}
# pull an OpenPGP-specified MPI off of a given stream, returning it as
# a Crypt::OpenSSL::Bignum.
sub read_mpi {
my $instr = shift;
my $readtally = shift;
my $bitlen;
read($instr, $bitlen, 2) or die "could not read MPI length.\n";
$bitlen = unpack('n', $bitlen);
$$readtally += 2;
my $bytestoread = POSIX::floor(($bitlen + 7)/8);
my $ret;
read($instr, $ret, $bytestoread) or die "could not read MPI body.\n";
$$readtally += $bytestoread;
return Crypt::OpenSSL::Bignum->new_from_bin($ret);
}
# FIXME: genericize these to accept either RSA or DSA keys:
sub make_rsa_pub_key_body {
my $key = shift;
my $key_timestamp = shift;
my ($n, $e) = $key->get_key_parameters();
return
pack('CN', 4, $key_timestamp).
pack('C', $asym_algos->{rsa}).
mpi_pack($n).
mpi_pack($e);
}
sub make_rsa_sec_key_body {
my $key = shift;
my $key_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($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
# RFC 4880, we're actually looking for u, the multiplicative inverse
# of p, mod q. This is why we're calculating the value directly
# with modular_multi_inverse.
return
pack('CN', 4, $key_timestamp).
pack('C', $asym_algos->{rsa}).
mpi_pack($n).
mpi_pack($e).
pack('C', 0). # seckey material is not encrypted -- see RFC 4880 sec 5.5.3
$secret_material.
pack('n', simple_checksum($secret_material));
}
# expects an RSA key (public or private) and a timestamp
sub fingerprint {
my $key = shift;
my $key_timestamp = shift;
my $rsabody = make_rsa_pub_key_body($key, $key_timestamp);
return Digest::SHA::sha1(pack('Cn', 0x99, length($rsabody)).$rsabody);
}
# FIXME: handle DSA keys as well!
sub makeselfsig {
my $rsa = shift;
my $uid = shift;
my $args = shift;
# strong assertion of identity is the default (for a self-sig):
if (! defined $args->{certification_type}) {
$args->{certification_type} = $sig_types->{positive_certification};
}
if (! defined $args->{sig_timestamp}) {
$args->{sig_timestamp} = time();
}
my $key_timestamp = $args->{key_timestamp} + 0;
# generate and aggregate subpackets:
# key usage flags:
my $flags = 0;
if (! defined $args->{usage_flags}) {
$flags = $usage_flags->{certify};
} else {
my @ff = split(",", $args->{usage_flags});
foreach my $f (@ff) {
if (! defined $usage_flags->{$f}) {
die "No such flag $f";
}
$flags |= $usage_flags->{$f};
}
}
my $usage_subpacket = pack('CCC', 2, $subpacket_types->{usage_flags}, $flags);
# 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_subpacket = '';
if (defined $args->{expiration}) {
my $expires_in = $args->{expiration} + 0;
$expiration_subpacket = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
}
# prefer AES-256, AES-192, AES-128, CAST5, 3DES:
my $pref_sym_algos = pack('CCCCCCC', 6, $subpacket_types->{preferred_cipher},
$ciphers->{aes256},
$ciphers->{aes192},
$ciphers->{aes128},
$ciphers->{cast5},
$ciphers->{tripledes}
);
# prefer SHA-512, SHA-384, SHA-256, SHA-224, RIPE-MD/160, SHA-1
my $pref_hash_algos = pack('CCCCCCCC', 7, $subpacket_types->{preferred_digest},
$digests->{sha512},
$digests->{sha384},
$digests->{sha256},
$digests->{sha224},
$digests->{ripemd160},
$digests->{sha1}
);
# prefer ZLIB, BZip2, ZIP
my $pref_zip_algos = pack('CCCCC', 4, $subpacket_types->{preferred_compression},
$zips->{zlib},
$zips->{bzip2},
$zips->{zip}
);
# we support the MDC feature:
my $feature_subpacket = pack('CCC', 2, $subpacket_types->{features},
$features->{mdc});
# keyserver preference: only owner modify (???):
my $keyserver_pref = pack('CCC', 2, $subpacket_types->{keyserver_prefs},
$keyserver_prefs->{nomodify});
$args->{hashed_subpackets} =
$usage_subpacket.
$expiration_subpacket.
$pref_sym_algos.
$pref_hash_algos.
$pref_zip_algos.
$feature_subpacket.
$keyserver_pref;
return gensig($rsa, $uid, $args);
}
# FIXME: handle non-RSA keys
# FIXME: this currently only makes self-sigs -- we should parameterize
# it to make certifications over keys other than the issuer.
sub gensig {
my $rsa = shift;
my $uid = shift;
my $args = shift;
# FIXME: allow signature creation using digests other than SHA256
$rsa->use_sha256_hash();
# see page 22 of RFC 4880 for why i think this is the right padding
# choice to use:
$rsa->use_pkcs1_padding();
if (! $rsa->check_key()) {
die "key does not check\n";
}
my $certtype = $args->{certification_type} + 0;
my $version = pack('C', 4);
my $sigtype = pack('C', $certtype);
# RSA
my $pubkey_algo = pack('C', $asym_algos->{rsa});
# SHA256 FIXME: allow signature creation using digests other than SHA256
my $hash_algo = pack('C', $digests->{sha256});
# 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 (because the
# timestamps will differ). How can we prevent this?
# this argument (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 $sig_timestamp = ($args->{sig_timestamp} + 0);
my $key_timestamp = ($args->{key_timestamp} + 0);
if ($key_timestamp > $sig_timestamp) {
die "key timestamp must not be later than signature timestamp\n";
}
my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $sig_timestamp);
my $hashed_subs = $creation_time_packet.$args->{hashed_subpackets};
my $subpacket_octets = pack('n', length($hashed_subs));
my $sig_data_to_be_hashed =
$version.
$sigtype.
$pubkey_algo.
$hash_algo.
$subpacket_octets.
$hashed_subs;
my $pubkey = make_rsa_pub_key_body($rsa, $key_timestamp);
# 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, $key_timestamp), 20 - 8, 8);
# the v4 signature trailer is:
# version number, literal 0xff, and then a 4-byte count of the
# signature data itself.
my $trailer = pack('CCN', 4, 0xff, length($sig_data_to_be_hashed));
my $uid_data =
pack('CN', 0xb4, length($uid)).
$uid;
my $datatosign =
$key_data.
$uid_data.
$sig_data_to_be_hashed.
$trailer;
# FIXME: handle signatures over digests other than SHA256:
my $data_hash = Digest::SHA::sha256_hex($datatosign);
my $issuer_packet = pack('CCa8', 9, $subpacket_types->{issuer}, $keyid);
my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign));
my $sig_body =
$sig_data_to_be_hashed.
pack('n', length($issuer_packet)).
$issuer_packet.
pack('n', hex(substr($data_hash, 0, 4))).
mpi_pack($sig);
return make_packet($packet_types->{sig}, $sig_body);
}
# FIXME: switch to passing the whole packet as the arg, instead of the
# input stream.
# FIXME: think about native perl representation of the packets instead.
# Put a user ID into the $data
sub finduid {
my $data = shift;
my $instr = shift;
my $tag = shift;
my $packetlen = shift;
my $dummy;
($tag == $packet_types->{uid}) or die "This should not be called on anything but a User ID packet\n";
read($instr, $dummy, $packetlen);
$data->{uid}->{$dummy} = {};
$data->{current}->{uid} = $dummy;
}
# find signatures associated with the given fingerprint and user ID.
sub findsig {
my $data = shift;
my $instr = shift;
my $tag = shift;
my $packetlen = shift;
($tag == $packet_types->{sig}) or die "No calling findsig on anything other than a signature packet.\n";
my $dummy;
my $readbytes = 0;
read($instr, $dummy, $packetlen - $readbytes) or die "Could not read in this packet.\n";
if ((! defined $data->{key}) ||
(! defined $data->{uid}) ||
(! defined $data->{uid}->{$data->{target}->{uid}})) {
# the user ID we are looking for has not been found yet.
return;
}
# FIXME: if we get two primary keys on stdin, both with the same
# targetd user ID, we'll store signatures from both keys, which is
# probably wrong.
# the current ID is not what we're looking for:
return if ($data->{current}->{uid} ne $data->{target}->{uid});
# just storing the raw signatures for the moment:
push @{$data->{sigs}}, make_packet($packet_types->{sig}, $dummy);
return;
}
# given an input stream and data, store the found key in data and
# consume the rest of the stream corresponding to the packet.
# data contains: (fpr: fingerprint to find, key: current best guess at key)
sub findkey {
my $data = shift;
my $instr = shift;
my $tag = shift;
my $packetlen = shift;
my $dummy;
my $ver;
my $readbytes = 0;
read($instr, $ver, 1) or die "could not read key version\n";
$readbytes += 1;
$ver = ord($ver);
if ($ver != 4) {
printf(STDERR "We only work with version 4 keys. This key appears to be version %s.\n", $ver);
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
return;
}
my $key_timestamp;
read($instr, $key_timestamp, 4) or die "could not read key timestamp.\n";
$readbytes += 4;
$key_timestamp = unpack('N', $key_timestamp);
my $algo;
read($instr, $algo, 1) or die "could not read key algorithm.\n";
$readbytes += 1;
$algo = ord($algo);
if ($algo != $asym_algos->{rsa}) {
printf(STDERR "We only support RSA keys (this key used algorithm %d).\n", $algo);
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
return;
}
## we have an RSA key.
my $modulus = read_mpi($instr, \$readbytes);
my $exponent = read_mpi($instr, \$readbytes);
my $pubkey = Crypt::OpenSSL::RSA->new_key_from_parameters($modulus, $exponent);
my $foundfpr = fingerprint($pubkey, $key_timestamp);
my $foundfprstr = Crypt::OpenSSL::Bignum->new_from_bin($foundfpr)->to_hex();
# left-pad with 0's to bring up to full 40-char (160-bit) fingerprint:
$foundfprstr = sprintf("%040s", $foundfprstr);
my $matched = 0;
# is this a match?
if ((!defined($data->{target}->{fpr})) ||
(substr($foundfprstr, -1 * length($data->{target}->{fpr})) eq $data->{target}->{fpr})) {
if (defined($data->{key})) {
die "Found two matching keys.\n";
}
$data->{key} = { 'rsa' => $pubkey,
'timestamp' => $key_timestamp };
$matched = 1;
}
if ($tag != $packet_types->{seckey} &&
$tag != $packet_types->{sec_subkey}) {
if ($readbytes < $packetlen) {
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
}
return;
}
if (!$matched) {
# we don't think the public part of this key matches
if ($readbytes < $packetlen) {
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
}
return;
}
my $s2k;
read($instr, $s2k, 1) or die "Could not read S2K octet.\n";
$readbytes += 1;
$s2k = ord($s2k);
if ($s2k != 0) {
printf(STDERR "We cannot handle encrypted secret keys. Skipping!\n") ;
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
return;
}
# secret material is unencrypted
# see http://tools.ietf.org/html/rfc4880#section-5.5.3
my $d = read_mpi($instr, \$readbytes);
my $p = read_mpi($instr, \$readbytes);
my $q = read_mpi($instr, \$readbytes);
my $u = read_mpi($instr, \$readbytes);
my $checksum;
read($instr, $checksum, 2) or die "Could not read checksum of secret key material.\n";
$readbytes += 2;
$checksum = unpack('n', $checksum);
# FIXME: compare with the checksum! how? the data is
# gone into the Crypt::OpenSSL::Bignum
$data->{key}->{rsa} = Crypt::OpenSSL::RSA->new_key_from_parameters($modulus,
$exponent,
$d,
$p,
$q);
$data->{key}->{rsa}->check_key() or die "Secret key is not a valid RSA key.\n";
if ($readbytes < $packetlen) {
read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
}
}
sub openpgp2rsa {
my $instr = shift;
my $fpr = shift;
if (defined $fpr) {
if (length($fpr) < 8) {
die "We need at least 8 hex digits of fingerprint.\n";
}
$fpr = uc($fpr);
}
my $data = { target => { fpr => $fpr,
},
};
my $subs = { $packet_types->{pubkey} => \&findkey,
$packet_types->{pub_subkey} => \&findkey,
$packet_types->{seckey} => \&findkey,
$packet_types->{sec_subkey} => \&findkey };
packetwalk($instr, $subs, $data);
return $data->{key}->{rsa};
}
sub findkeyfprs {
my $data = shift;
my $instr = shift;
my $tag = shift;
my $packetlen = shift;
findkey($data, $instr, $tag, $packetlen);
if (defined($data->{key})) {
if (defined($data->{key}->{rsa}) && defined($data->{key}->{timestamp})) {
$data->{keys}->{fingerprint($data->{key}->{rsa}, $data->{key}->{timestamp})} = $data->{key};
} else {
die "should have found some key here";
}
undef($data->{key});
}
};
sub getallprimarykeys {
my $instr = shift;
my $subs = { $packet_types->{pubkey} => \&findkeyfprs,
$packet_types->{seckey} => \&findkeyfprs,
};
my $data = {target => { } };
packetwalk($instr, $subs, $data);
if (defined $data->{keys}) {
return $data->{keys};
} else {
return {};
}
}
sub adduserid {
my $instr = shift;
my $fpr = shift;
my $uid = shift;
my $args = shift;
if ((! defined $fpr) ||
(length($fpr) < 8)) {
die "We need at least 8 hex digits of fingerprint.\n";
}
$fpr = uc($fpr);
if (! defined $uid) {
die "No User ID defined.\n";
}
my $data = { target => { fpr => $fpr,
uid => $uid,
},
};
my $subs = { $packet_types->{seckey} => \&findkey,
$packet_types->{uid} => \&finduid,
$packet_types->{sig} => \&findsig,
};
packetwalk($instr, $subs, $data);
if ((! defined $data->{key}) ||
(! defined $data->{key}->{rsa}) ||
(! defined $data->{key}->{timestamp})) {
die "The key requested was not found.\n"
}
if (defined $data->{uid}->{$uid}) {
die "The requested User ID '$uid' is already associated with this key.\n";
}
$args->{key_timestamp} = $data->{key}->{timestamp};
return
make_packet($packet_types->{pubkey}, make_rsa_pub_key_body($data->{key}->{rsa}, $data->{key}->{timestamp})).
make_packet($packet_types->{uid}, $uid).
makeselfsig($data->{key}->{rsa},
$uid,
$args);
}
sub revokeuserid {
my $instr = shift;
my $fpr = shift;
my $uid = shift;
my $sigtime = shift;
if ((! defined $fpr) ||
(length($fpr) < 8)) {
die "We need at least 8 hex digits of fingerprint.\n";
}
$fpr = uc($fpr);
if (! defined $uid) {
die "No User ID defined.\n";
}
my $data = { target => { fpr => $fpr,
uid => $uid,
},
};
my $subs = { $packet_types->{seckey} => \&findkey,
$packet_types->{uid} => \&finduid,
$packet_types->{sig} => \&findsig,
};
packetwalk($instr, $subs, $data);
if ((! defined $data->{uid}) ||
(! defined $data->{uid}->{$uid})) {
die "The User ID \"$uid\" is not associated with this key";
}
if ((! defined $data->{key}) ||
(! defined $data->{key}->{rsa}) ||
(! defined $data->{key}->{timestamp})) {
die "The key requested was not found."
}
my $revocation_reason = 'No longer using this hostname';
if (defined $data->{revocation_reason}) {
$revocation_reason = $data->{revocation_reason};
}
my $rev_reason_subpkt = prefixsubpacket(pack('CC',
$subpacket_types->{revocation_reason},
$revocation_reasons->{user_id_no_longer_valid}).
$revocation_reason);
if (! defined $sigtime) {
$sigtime = time();
}
# what does a signature like this look like?
my $args = { key_timestamp => $data->{key}->{timestamp},
sig_timestamp => $sigtime,
certification_type => $sig_types->{certification_revocation},
hashed_subpackets => $rev_reason_subpkt,
};
return
make_packet($packet_types->{pubkey}, make_rsa_pub_key_body($data->{key}->{rsa}, $data->{key}->{timestamp})).
make_packet($packet_types->{uid}, $uid).
join('', @{$data->{sigs}}).
gensig($data->{key}->{rsa}, $uid, $args);
}
# see 5.2.3.1 for tips on how to calculate the length of a subpacket:
sub prefixsubpacket {
my $subpacket = shift;
my $len = length($subpacket);
my $prefix;
use bytes;
if ($len < 192) {
# one byte:
$prefix = pack('C', $len);
} elsif ($len < 16576) {
my $in = $len - 192;
my $second = $in%256;
my $first = ($in - $second)>>8;
$prefix = pack('CC', $first + 192, $second)
} else {
$prefix = pack('CN', 255, $len);
}
return $prefix.$subpacket;
}
sub packetwalk {
my $instr = shift;
my $subs = shift;
my $data = shift;
my $packettag;
my $dummy;
my $tag;
while (! eof($instr)) {
read($instr, $packettag, 1);
$packettag = ord($packettag);
my $packetlen;
if ( ! (0x80 & $packettag)) {
die "This is not an OpenPGP packet\n";
}
if (0x40 & $packettag) {
# this is a new-format packet.
$tag = (0x3f & $packettag);
my $nextlen = 0;
read($instr, $nextlen, 1);
$nextlen = ord($nextlen);
if ($nextlen < 192) {
$packetlen = $nextlen;
} elsif ($nextlen < 224) {
my $newoct;
read($instr, $newoct, 1);
$newoct = ord($newoct);
$packetlen = (($nextlen - 192) << 8) + ($newoct) + 192;
} elsif ($nextlen == 255) {
read($instr, $nextlen, 4);
$packetlen = unpack('N', $nextlen);
} else {
# packet length is undefined.
}
} else {
# this is an old-format packet.
my $lentype;
$lentype = 0x03 & $packettag;
$tag = ( 0x3c & $packettag ) >> 2;
if ($lentype == 0) {
read($instr, $packetlen, 1) or die "could not read packet length\n";
$packetlen = unpack('C', $packetlen);
} elsif ($lentype == 1) {
read($instr, $packetlen, 2) or die "could not read packet length\n";
$packetlen = unpack('n', $packetlen);
} elsif ($lentype == 2) {
read($instr, $packetlen, 4) or die "could not read packet length\n";
$packetlen = unpack('N', $packetlen);
} else {
# packet length is undefined.
}
}
if (! defined($packetlen)) {
die "Undefined packet lengths are not supported.\n";
}
if (defined $subs->{$tag}) {
$subs->{$tag}($data, $instr, $tag, $packetlen);
} else {
read($instr, $dummy, $packetlen) or die "Could not skip past this packet!\n";
}
}
return $data->{key};
}
for (basename($0)) {
if (/^pem2openpgp$/) {
my $rsa;
my $stdin;
my $uid = shift;
defined($uid) or die "You must specify a user ID string.\n";
# FIXME: fail if there is no given user ID; or should we default to
# hostname_long() from Sys::Hostname::Long ?
if (defined $ENV{PEM2OPENPGP_NEWKEY}) {
$rsa = Crypt::OpenSSL::RSA->generate_key($ENV{PEM2OPENPGP_NEWKEY});
} else {
$stdin = do {
local $/; # slurp!
<STDIN>;
};
$rsa = Crypt::OpenSSL::RSA->new_private_key($stdin);
}
my $key_timestamp = $ENV{PEM2OPENPGP_KEY_TIMESTAMP};
my $sig_timestamp = $ENV{PEM2OPENPGP_TIMESTAMP};
$sig_timestamp = time() if (!defined $sig_timestamp);
$key_timestamp = $sig_timestamp if (!defined $key_timestamp);
print
make_packet($packet_types->{seckey}, make_rsa_sec_key_body($rsa, $key_timestamp)).
make_packet($packet_types->{uid}, $uid).
makeselfsig($rsa,
$uid,
{ sig_timestamp => $sig_timestamp,
key_timestamp => $key_timestamp,
expiration => $ENV{PEM2OPENPGP_EXPIRATION},
usage_flags => $ENV{PEM2OPENPGP_USAGE_FLAGS},
}
);
}
elsif (/^openpgp2ssh$/) {
my $fpr = shift;
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
my $key = openpgp2rsa($instream, $fpr);
if (defined($key)) {
if ($key->is_private()) {
print $key->get_private_key_string();
} else {
print "ssh-rsa ".encode_base64(openssh_pubkey_pack($key), '')."\n";
}
} else {
die "No matching key found.\n";
}
}
elsif (/^bruteforce_keyid$/) {
my $openpgp_key;
my $keyid;
my $fingerprint;
my $rsa;
my $ts;
my $time_diff;
my $tries = 0;
my $tries_per_sec;
my $uid = shift;
defined($uid) or die "You must specify a user ID string.\n";
my $target_keyid = shift;
defined($target_keyid) or die "You must specify an 8-character key ID.\n";
# timestamp starts with now
my $ts_now = time();
my $ts_three_years_ago = $ts_now - 60*60*24*365*3;
while (1) {
# generate a new RSA key
print("Generating new RSA key\n");
$rsa = Crypt::OpenSSL::RSA->generate_key(4096);
$ts = $ts_now;
while ($ts >= $ts_three_years_ago) {
# get the key id
$fingerprint = uc(unpack("H*", fingerprint($rsa, $ts)));
$keyid = substr($fingerprint, 32, 8);
if ($target_keyid eq $keyid) {
# make a new OpenPGP key with this timestamp
$openpgp_key =
make_packet($packet_types->{seckey}, make_rsa_sec_key_body($rsa, $ts)).
make_packet($packet_types->{uid}, $uid).
makeselfsig( $rsa, $uid, { sig_timestamp => $ts, key_timestamp => $ts });
# write $openpgp_key to $keyid.gpg
open(FILE, ">$keyid.gpg");
print FILE $openpgp_key;
close(FILE);
$time_diff = time() - $ts_now;
die("\nFound a collision in $time_diff seconds! Saved to $keyid.gpg.\n");
}
$tries++;
if($tries % 100 == 0) {
$time_diff = time() - $ts_now;
if($time_diff == 0) {
$tries_per_sec = 0;
} else {
$tries_per_sec = int($tries / $time_diff);
}
print("\r$tries tries [$tries_per_sec / sec]");
}
$ts--;
}
print("\n");
}
}
elsif (/^keytrans$/) {
# subcommands when keytrans is invoked directly are UNSUPPORTED,
# UNDOCUMENTED, and WILL NOT BE MAINTAINED.
my $subcommand = shift;
for ($subcommand) {
if (/^revokeuserid$/) {
my $fpr = shift;
my $uid = shift;
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
my $revcert = revokeuserid($instream, $fpr, $uid, $ENV{PEM2OPENPGP_TIMESTAMP});
print $revcert;
} elsif (/^adduserid$/) {
my $fpr = shift;
my $uid = shift;
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
my $newuid = adduserid($instream, $fpr, $uid,
{ sig_timestamp => $ENV{PEM2OPENPGP_TIMESTAMP},
expiration => $ENV{PEM2OPENPGP_EXPIRATION},
usage_flags => $ENV{PEM2OPENPGP_USAGE_FLAGS},
});
print $newuid;
} elsif (/^listfprs$/) {
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
my $keys = getallprimarykeys($instream);
printf("%s\n", join("\n", map { uc(unpack('H*', $_)) } keys(%{$keys})));
} elsif (/^sshfpr$/) {
use MIME::Base64;
my $b64keyblob;
my $dummy;
while (($dummy,$b64keyblob) = split(/ /, <STDIN>)) {
printf("%s\n", sshfpr(decode_base64($b64keyblob)));
}
} elsif (/^openpgp2sshfpr$/) {
my $fpr = shift;
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
my $key = openpgp2rsa($instream, $fpr);
if (defined($key)) {
# openssh uses MD5 for key fingerprints:
printf("%d %s %s\n",
$key->size() * 8, # size() is in bytes -- we want bits
sshfpr(openssh_pubkey_pack($key)),
'(RSA)', # FIXME when we support other than RSA.
);
} else {
die "No matching key found.\n";
}
} else {
die "Unrecognized subcommand. keytrans subcommands are not a stable interface!\n";
}
}
}
else {
die "Unrecognized keytrans call.\n";
}
}