-#!/usr/bin/perl -w -T
+#!/usr/bin/perl -T
# keytrans: this is an RSA key translation utility; it is capable of
# transforming RSA keys (both public keys and secret keys) between
use Crypt::OpenSSL::RSA;
use Crypt::OpenSSL::Bignum;
use Crypt::OpenSSL::Bignum::CTX;
-use Digest::SHA1;
+use Digest::SHA;
use MIME::Base64;
use POSIX;
########### Math/Utility Functions ##############
-# see the bottom of page 43 of RFC 4880
+# see the bottom of page 44 of RFC 4880 (http://tools.ietf.org/html/rfc4880#page-44)
sub simple_checksum {
my $bytes = shift;
- return unpack("%32W*",$bytes) % 65536;
+ return unpack("%16C*",$bytes);
}
# calculate the multiplicative inverse of a mod b this is euclid's
# FIXME: genericize these to accept either RSA or DSA keys:
sub make_rsa_pub_key_body {
my $key = shift;
- my $timestamp = shift;
+ my $key_timestamp = shift;
my ($n, $e) = $key->get_key_parameters();
return
- pack('CN', 4, $timestamp).
+ 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 $timestamp = 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();
# with modular_multi_inverse.
return
- pack('CN', 4, $timestamp).
+ pack('CN', 4, $key_timestamp).
pack('C', $asym_algos->{rsa}).
mpi_pack($n).
mpi_pack($e).
# expects an RSA key (public or private) and a timestamp
sub fingerprint {
my $key = shift;
- my $timestamp = shift;
+ my $key_timestamp = shift;
- my $rsabody = make_rsa_pub_key_body($key, $timestamp);
+ my $rsabody = make_rsa_pub_key_body($key, $key_timestamp);
- return Digest::SHA1::sha1(pack('Cn', 0x99, length($rsabody)).$rsabody);
+ return Digest::SHA::sha1(pack('Cn', 0x99, length($rsabody)).$rsabody);
}
my $uid = shift;
my $args = shift;
- $rsa->use_sha1_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";
+ # strong assertion of identity is the default (for a self-sig):
+ if (! defined $args->{certification_type}) {
+ $args->{certification_type} = $sig_types->{positive_certification};
}
- my $version = pack('C', 4);
- # strong assertion of identity:
- my $sigtype = pack('C', $sig_types->{positive_certification});
- # RSA
- my $pubkey_algo = pack('C', $asym_algos->{rsa});
- # SHA1
- my $hash_algo = pack('C', $digests->{sha1});
-
- # 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 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 $args->{timestamp}) {
- $timestamp = ($args->{timestamp} + 0);
- } else {
- $timestamp = time();
+ if (! defined $args->{sig_timestamp}) {
+ $args->{sig_timestamp} = time();
}
+ if (! defined $args->{key_timestamp}) {
+ $args->{key_timestamp} = $args->{sig_timestamp} + 0;
+ }
+ my $key_timestamp = $args->{key_timestamp};
- my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp);
-
+ # generate and aggregate subpackets:
+ # key usage flags:
my $flags = 0;
if (! defined $args->{usage_flags}) {
$flags = $usage_flags->{certify};
$flags |= $usage_flags->{$f};
}
}
-
- my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $flags);
-
+ 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_packet = '';
+ my $expiration_subpacket = '';
if (defined $args->{expiration}) {
my $expires_in = $args->{expiration} + 0;
- $expiration_packet = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
+ $expiration_subpacket = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
}
$ciphers->{tripledes}
);
- # prefer SHA-1, SHA-256, RIPE-MD/160
- my $pref_hash_algos = pack('CCCCC', 4, $subpacket_types->{preferred_digest},
- $digests->{sha1},
+ # 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->{ripemd160}
+ $digests->{sha224},
+ $digests->{ripemd160},
+ $digests->{sha1}
);
# prefer ZLIB, BZip2, ZIP
my $keyserver_pref = pack('CCC', 2, $subpacket_types->{keyserver_prefs},
$keyserver_prefs->{nomodify});
- my $subpackets_to_be_hashed =
- $creation_time_packet.
- $usage_packet.
- $expiration_packet.
+
+ $args->{hashed_subpackets} =
+ $usage_subpacket.
+ $expiration_subpacket.
$pref_sym_algos.
$pref_hash_algos.
$pref_zip_algos.
$feature_subpacket.
$keyserver_pref;
- my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
+ return
+ make_packet($packet_types->{seckey}, make_rsa_sec_key_body($rsa, $key_timestamp)).
+ make_packet($packet_types->{uid}, $uid).
+ gensig($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";
+ }
+
+ 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";
+ }
+
+ 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.
$pubkey_algo.
$hash_algo.
$subpacket_octets.
- $subpackets_to_be_hashed;
+ $hashed_subs;
- my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
- my $seckey = make_rsa_sec_key_body($rsa, $timestamp);
+ 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, $timestamp), 20 - 8, 8);
+ my $keyid = substr(fingerprint($rsa, $key_timestamp), 20 - 8, 8);
# the v4 signature trailer is:
$sig_data_to_be_hashed.
$trailer;
- my $data_hash = Digest::SHA1::sha1_hex($datatosign);
+
+ # 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}, $keyid);
pack('n', hex(substr($data_hash, 0, 4))).
mpi_pack($sig);
- return
- make_packet($packet_types->{seckey}, $seckey).
- make_packet($packet_types->{uid}, $uid).
- make_packet($packet_types->{sig}, $sig_body);
+ return make_packet($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 == $packet_types->{uid}) or die "This should not be called on anything but a User ID packet";
+
+ read($instr, $dummy, $packetlen);
+ $data->{uid} = {} unless defined $data->{uid};
+ $data->{uid}->{$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.";
+
+ my $dummy;
+ my $readbytes = 0;
+
+ if ((undef $data->{key}) ||
+ (undef $data->{uid}) ||
+ (undef $data->{uid}->{$data->{target}->{uid}})) {
+ # this is not the user ID we are looking for.
+ read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
+ }
+
+ read($instr, $data, 6) or die "could not read signature header\n";
+ my ($ver, $sigtype, $pubkeyalgo, $digestalgo, $subpacketsize) = unpack('CCCCn', $data);
+ if ($ver != 4) {
+ printf(STDERR "We only work with version 4 signatures.");
+ read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
+ return;
+ }
+ if ($pubkeyalgo != $asym_algos->{rsa}) {
+ printf(STDERR "We can only work with RSA at the moment");
+ read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
+ return;
+ }
+ if ($sigtype != $sig_types->{positive_certification}) {
+ # FIXME: some weird implementations might have made generic,
+ # persona, or casual certifications instead of positive
+ # certifications for self-sigs. Probably should handle them too.
+ read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
+ return;
+ }
+
+ my $subpackets;
+ read($instr, $subpackets, $subpacketsize) or die "could not read hashed signature subpackets.\n";
+
+ read($instr, $subpacketsize, 2) or die "could not read unhashed signature subpacket size.\n";
+ $subpacketsize = unpack('n', $subpacketsize);
+
+ my $unhashedsubpackets;
+ read($instr, $unhashedsubpackets, $subpacketsize) or die "could not read unhashed signature subpackets.\n";
+
+ my $hashtail;
+ read($instr, $hashtail, 2) or die "could not read left 16 bits of digest.\n";
+
+ # FIXME: RSA signatures should read in how many MPIs?
+
}
+# 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", $foundfprstr);
+
+ # is this a match?
+ if ((!defined($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' => $key_timestamp };
+ }
+
+ if ($tag != $packet_types->{seckey} &&
+ $tag != $packet_types->{sec_subkey}) {
+ if ($readbytes < $packetlen) {
+ read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
+ }
+ return;
+ }
+ if (!defined($data->{key})) {
+ # 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 openpgp2ssh {
+sub openpgp2rsa {
my $instr = shift;
my $fpr = shift;
$fpr = uc($fpr);
}
+ my $data = { '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 revokeuserid {
+ my $instr = shift;
+ my $fpr = shift;
+ my $uid = 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,
+ },
+ };
+ my $subs = { $packet_types->{seckey} => \&findkey,
+ $packet_types->{uid} => \&finduid
+ };
+
+ packetwalk($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."
+ }
+
+ # what does a signature like this look like?
+
+ return 'abc';
+}
+
+
+
+sub packetwalk {
+ my $instr = shift;
+ my $subs = shift;
+ my $data = shift;
+
my $packettag;
my $dummy;
my $tag;
- my $key;
-
while (! eof($instr)) {
read($instr, $packettag, 1);
$packettag = ord($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);
# packet length is undefined.
}
} else {
+ # this is an old-format packet.
my $lentype;
$lentype = 0x03 & $packettag;
$tag = ( 0x3c & $packettag ) >> 2;
die "Undefined packet lengths are not supported.\n";
}
- if ($tag == $packet_types->{pubkey} ||
- $tag == $packet_types->{pub_subkey} ||
- $tag == $packet_types->{seckey} ||
- $tag == $packet_types->{sec_subkey}) {
- 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";
- } else {
-
- my $timestamp;
- read($instr, $timestamp, 4) or die "could not read key timestamp.\n";
- $readbytes += 4;
- $timestamp = unpack('N', $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";
- } else {
- ## 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, $timestamp);
-
- my $foundfprstr = Crypt::OpenSSL::Bignum->new_from_bin($foundfpr)->to_hex();
-
- # is this a match?
- if ((!defined($fpr)) ||
- (substr($foundfprstr, -1 * length($fpr)) eq $fpr)) {
- if (defined($key)) {
- die "Found two matching keys.\n";
- }
- $key = $pubkey;
- }
-
- if ($tag == $packet_types->{seckey} ||
- $tag == $packet_types->{sec_subkey}) {
- if (!defined($key)) { # we don't think the public part of
- # this key matches
- read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\n";
- } else {
- my $s2k;
- read($instr, $s2k, 1) or die "Could not read S2K octet.\n";
- $readbytes += 1;
- $s2k = ord($s2k);
- if ($s2k == 0) {
- # 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
-
- $key = Crypt::OpenSSL::RSA->new_key_from_parameters($modulus,
- $exponent,
- $d,
- $p,
- $q);
-
- $key->check_key() or die "Secret key is not a valid RSA key.\n";
- } else {
- print(STDERR "We cannot handle encrypted secret keys. Skipping!\n") ;
- read($instr, $dummy, $packetlen - $readbytes) or die "Could not skip past this packet.\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 $key;
+ return $data->{key};
}
# 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 {
print pem2openpgp($rsa,
$uid,
- { timestamp => $ENV{PEM2OPENPGP_TIMESTAMP},
+ { sig_timestamp => $ENV{PEM2OPENPGP_TIMESTAMP},
+ key_timestamp => $ENV{PEM2OPENPGP_KEY_TIMESTAMP},
expiration => $ENV{PEM2OPENPGP_EXPIRATION},
usage_flags => $ENV{PEM2OPENPGP_USAGE_FLAGS},
}
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
- my $key = openpgp2ssh($instream, $fpr);
+ my $key = openpgp2rsa($instream, $fpr);
if (defined($key)) {
if ($key->is_private()) {
print $key->get_private_key_string();
die "No matching key found.\n";
}
}
+ elsif (/^revokeuserid$/) {
+ my $fpr = shift;
+ my $uid = shift;
+ my $instream;
+ open($instream,'-');
+ binmode($instream, ":bytes");
+
+ my $revcert = revokeuserid($instream, $fpr, $uid);
+
+ print $revcert;
+ }
else {
die "Unrecognized keytrans call.\n";
}
projects / monkeysphere.git / blobdiff