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-rwxr-xr-xsrc/keytrans/pem2openpgp514
1 files changed, 357 insertions, 157 deletions
diff --git a/src/keytrans/pem2openpgp b/src/keytrans/pem2openpgp
index 2631da6..40188c7 100755
--- a/src/keytrans/pem2openpgp
+++ b/src/keytrans/pem2openpgp
@@ -23,6 +23,7 @@
use strict;
use warnings;
+use File::Basename;
use Crypt::OpenSSL::RSA;
use Crypt::OpenSSL::Bignum;
use Crypt::OpenSSL::Bignum::CTX;
@@ -32,12 +33,6 @@ 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; or should we default to
-# hostname_long() from Sys::Hostname::Long ?
-
-
my $old_format_packet_lengths = { one => 0,
two => 1,
four => 2,
@@ -293,6 +288,51 @@ sub mpi_pack {
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 $bitlen;
+ read($instr, $bitlen, 2) or die "could not read MPI length.\n";
+ $bitlen = unpack('n', $bitlen);
+
+ my $ret;
+ read($instr, $ret, ($bitlen + 7)/8) or die "could not read MPI body.\n";
+ 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;
@@ -348,172 +388,332 @@ sub fingerprint {
}
-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>);
-}
+# FIXME: handle DSA keys as well!
+sub pem2openpgp {
+ my $rsa = shift;
+ my $uid = shift;
+ my $args = shift;
-$rsa->use_sha1_hash();
+ $rsa->use_sha1_hash();
-# see page 22 of RFC 4880 for why i think this is the right padding
-# choice to use:
-$rsa->use_pkcs1_padding();
+ # 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";
-}
+ if (! $rsa->check_key()) {
+ die "key does not check";
+ }
-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 $ENV{PEM2OPENPGP_TIMESTAMP}) {
- $timestamp = ($ENV{PEM2OPENPGP_TIMESTAMP} + 0);
-} else {
- $timestamp = time();
-}
+ 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();
+ }
-my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp);
+ my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp);
-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";
+ 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};
}
- $flags |= $usage_flags->{$f};
}
+
+ my $usage_packet = 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 = '';
+ if (defined $args->{expiration}) {
+ my $expires_in = $args->{expiration} + 0;
+ $expiration_packet = 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-1, SHA-256, RIPE-MD/160
+ my $pref_hash_algos = pack('CCCCC', 4, $subpacket_types->{preferred_digest},
+ $digests->{sha1},
+ $digests->{sha256},
+ $digests->{ripemd160}
+ );
+
+ # 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});
+
+ my $subpackets_to_be_hashed =
+ $creation_time_packet.
+ $usage_packet.
+ $expiration_packet.
+ $pref_sym_algos.
+ $pref_hash_algos.
+ $pref_zip_algos.
+ $feature_subpacket.
+ $keyserver_pref;
+
+ my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
+
+ my $sig_data_to_be_hashed =
+ $version.
+ $sigtype.
+ $pubkey_algo.
+ $hash_algo.
+ $subpacket_octets.
+ $subpackets_to_be_hashed;
+
+ my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
+ my $seckey = make_rsa_sec_key_body($rsa, $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);
+
+ # 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;
+
+ 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));
+
+ 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->{seckey}, $seckey).
+ make_packet($packet_types->{uid}, $uid).
+ make_packet($packet_types->{sig}, $sig_body);
}
-my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $flags);
+sub openpgp2ssh {
+ my $instr = shift;
+ my $fpr = shift;
+
+ if (defined $fpr) {
+ if (length($fpr) < 8) {
+ die "We need at least 8 hex digits of fingerprint.\n";
+ }
+ }
+
+ my $packettag;
+ my $dummy;
+ my $tag;
+
+ my $key;
+
+ while (! eof($instr)) {
+ read($instr, $packettag, 1);
+ $packettag = ord($packettag);
+
+ my $packetlen;
+ if ( ! (0x80 & $packettag)) {
+ die "This is not an OpenPGP packet\n";
+ }
+ if (0x40 & $packettag) {
+ $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 {
+ 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 ($tag == $packet_types->{pubkey} ||
+ $tag == $packet_types->{pub_subkey} ||
+ $tag == $packet_types->{seckey} ||
+ $tag == $packet_types->{sec_subkey}) {
+ my $ver;
+ read($instr, $ver, 1) or die "could not read key version\n";
+ $ver = ord($ver);
+ if ($ver != 4) {
+ printf(STDERR "We only work with version 4 keys. This key appears to be version $ver.\n");
+ read($instr, $dummy, $packetlen - 1) or die "Could not skip past this packet.\n";
+ } else {
+
+ my $timestamp;
+ read($instr, $timestamp, 4) or die "could not read key timestamp.\n";
+ $timestamp = unpack('N', $timestamp);
+
+ my $algo;
+ read($instr, $algo, 1) or die "could not read key algorithm.\n";
+ $algo = ord($algo);
+ if ($algo != $asym_algos->{rsa}) {
+ printf(STDERR "We only support RSA keys (this key used algorithm %d).\n", $algo);
+ read($instr, $dummy, $packetlen - 6) or die "Could not skip past this packet.\n";
+ } else {
+ ## we have an RSA key.
+ my $modulus = read_mpi($instr);
+ my $exponent = read_mpi($instr);
+
+ 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 == $packet_types->{sec_subkey}) {
+ die "Cannot deal with secret keys yet!\n";
+ }
+
+ }
+ }
+ } else {
+ read($instr, $dummy, $packetlen) or die "Could not skip past this packet!\n";
+ }
+ }
-# 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}, $expires_in);
+ if (defined($key)) {
+ return "ssh-rsa ".encode_base64(openssh_pubkey_pack($key), '');
+ }
}
-# 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-1, SHA-256, RIPE-MD/160
-my $pref_hash_algos = pack('CCCCC', 4, $subpacket_types->{preferred_digest},
- $digests->{sha1},
- $digests->{sha256},
- $digests->{ripemd160}
- );
-
-# 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});
-
-my $subpackets_to_be_hashed =
- $creation_time_packet.
- $usage_packet.
- $expiration_packet.
- $pref_sym_algos.
- $pref_hash_algos.
- $pref_zip_algos.
- $feature_subpacket.
- $keyserver_pref;
-
-my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
-
-my $sig_data_to_be_hashed =
- $version.
- $sigtype.
- $pubkey_algo.
- $hash_algo.
- $subpacket_octets.
- $subpackets_to_be_hashed;
-
-my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
-my $seckey = make_rsa_sec_key_body($rsa, $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);
-
-# 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;
-
-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));
-
-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($sig);
-
-print
- make_packet($packet_types->{seckey}, $seckey).
- make_packet($packet_types->{uid}, $uid).
- make_packet($packet_types->{sig}, $sig_body);
+for (basename($0)) {
+ if (/^pem2openpgp$/) {
+ my $rsa;
+ my $stdin;
+ 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 $uid = shift;
+
+ # FIXME: fail if there is no given user ID; or should we default to
+ # hostname_long() from Sys::Hostname::Long ?
+
+ print pem2openpgp($rsa,
+ $uid,
+ { timestamp => $ENV{PEM2OPENPGP_TIMESTAMP},
+ expiration => $ENV{PEM2OPENPGP_EXPIRATION},
+ usage_flags => $ENV{PEM2OPENPGP_USAGE_FLAGS},
+ }
+ );
+ }
+ elsif (/^openpgp2ssh$/) {
+ my $fpr = shift;
+ my $instream;
+ open($instream,'-');
+ binmode($instream, ":bytes");
+ print openpgp2ssh($instream, $fpr);
+ }
+ else {
+ die "Unrecognized keytrans call.\n";
+ }
+}
generated by cgit v1.2.3 (git 2.46.0) at 2024-12-25 18:35:44 +0000