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Support Ed25519 in privsign and cert gen
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Note that 'sign -O' will not work with Ed25519 as gpg always
hashes the data, whereas Ed25519 wants the unhashed data as
input.
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@mlschroe
mlschroe committed Jul 28, 2022
1 parent f496979 commit 52bb761
Showing 1 changed file with 104 additions and 46 deletions.
150 changes: 104 additions & 46 deletions signd
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Expand Up @@ -176,7 +176,7 @@ sub priv2pub {
}
my $info = $infos ? {} : undef;
push @$infos, $info if $info;
$info->{'algo'} = $pkalgo;
$info->{'algo'} = $pkalgo if $info;
my $mpinum;
my $smpinum;
if ($pkalgo == 1) { # RSA
Expand All @@ -188,6 +188,13 @@ sub priv2pub {
} elsif ($pkalgo == 16 || $pkalgo == 20) { # Elgamal
$mpinum = 3;
$smpinum = 1;
} elsif ($pkalgo == 22) { # EdDSA
$mpinum = 1;
$smpinum = 1;
my $oidlen = unpack('C', substr($pack, $mpioff));
die("bad curve len") if $oidlen == 0 || $oidlen == 255;
$info->{'curve'} = substr($pack, $mpioff + 1, $oidlen) if $info;
$mpioff += $oidlen + 1;
} else {
die("unknown public key algorithm $pkalgo\n");
}
Expand Down Expand Up @@ -234,13 +241,74 @@ sub packlen {
}
}

sub packtag {
return chr($_[0]).packlen(length($_[1])).$_[1];
}

sub packmpi {
my ($mpi) = @_;
$mpi = chr(0).$mpi;
$mpi = substr($mpi, 1) while length($mpi) > 1 && ord($mpi) == 0 && (ord(substr($mpi, 1, 1)) & 0x80) == 0;
return chr(2).packlen(length($mpi)).$mpi;
}

sub priv2openssl_ed25519 {
my ($q, $s) = @_;
die("bad ed25519 Q\n") unless length($q) == 33 && unpack('C', $q) == 0x40;
die("bad ed25519 S\n") unless length($s) <= 32;
$s = "\0$s" while length($s) < 32;
my $asn1 = '';
$asn1 .= packtag(0x02, "\x00"); # INTEGER 0
$asn1 .= packtag(0x30, "\x06\x03\x2b\x65\x70"); # SEQUENCE(OID 1.3.101.112)
$asn1 .= packtag(0x04, packtag(0x04, $s)); # OCTET_STRING(OCTET_STRING(key))
$asn1 = packtag(0x30, $asn1);
my $base64 = encode_base64($asn1, '');
my $pem = "-----BEGIN PRIVATE KEY-----\n";
$pem .= "$_\n" for $base64 =~ /(.{1,64})/g;
$pem .= "-----END PRIVATE KEY-----\n";
return $pem;
}

sub priv2openssl_rsa {
my (@s) = @_;
# calculate missing stuff:
# modulus INTEGER, -- n
# publicExponent INTEGER, -- e
# privateExponent INTEGER, -- d 2
# prime1 INTEGER, -- p 4
# prime2 INTEGER, -- q 3
# exponent1 INTEGER, -- d mod (p-1)
# exponent2 INTEGER, -- d mod (q-1)
# coefficient INTEGER, -- (inverse of q) mod p
my $d = Math::BigInt->new('0x' . unpack('H*', $s[2]));
my $p = Math::BigInt->new('0x' . unpack('H*', $s[4]));
my $q = Math::BigInt->new('0x' . unpack('H*', $s[3]));
my $ex1 = $d->copy()->bmod($p->copy()->bdec());
my $ex2 = $d->copy()->bmod($q->copy()->bdec());
$ex1 = pack('H*', substr($ex1->as_hex(), 2));
$ex2 = pack('H*', substr($ex2->as_hex(), 2));

# asn1 encode
my $asn1 = '';
$asn1 .= packmpi(chr(0));
$asn1 .= packmpi($s[0]);
$asn1 .= packmpi($s[1]);
$asn1 .= packmpi($s[2]);
$asn1 .= packmpi($s[4]);
$asn1 .= packmpi($s[3]);
$asn1 .= packmpi($ex1);
$asn1 .= packmpi($ex2);
$asn1 .= packmpi($s[5]);
$asn1 = packtag(0x30, $asn1);

# pem encode
my $base64 = encode_base64($asn1, '');
my $pem = "-----BEGIN RSA PRIVATE KEY-----\n";
$pem .= "$_\n" for $base64 =~ /(.{1,64})/g;
$pem .= "-----END RSA PRIVATE KEY-----\n";
return $pem;
}

sub priv2openssl {
my ($gpgpackets, $search_for) = @_;
die("empty privkey\n") unless $gpgpackets;
Expand All @@ -263,11 +331,24 @@ sub priv2openssl {
} else {
die("unknown public key version $pkver\n");
}
die("not an RSA private key\n") unless $pkalgo == 1;
$pack = substr($pack, $mpioff);
my ($mpinum, $smpinum, $curve);
if ($pkalgo == 22) {
my $curvelen = unpack('C', $pack);
die("bad EdDSA curve len\n") if $curvelen == 0 || $curvelen == 255 || $curvelen + 1 > length($pack);
$curve = substr($pack, 1, $curvelen);
$pack = substr($pack, $curvelen + 1);
$mpinum = 1;
$smpinum = 1;
} elsif ($pkalgo == 1) {
$mpinum = 2;
$smpinum = 4;
} else {
die("not an RSA or EdDSA private key\n");
}
my @s;
for my $i (0, 1, 2, 3, 4, 5) {
if ($i == 2) {
for my $i (0..($mpinum + $smpinum - 1)) {
if ($i == $mpinum) {
my $encrypted = unpack('C', $pack);
die("private key is encrypted\n") if $encrypted;
$pack = substr($pack, 1);
Expand All @@ -278,44 +359,9 @@ sub priv2openssl {
push @s, substr($pack, 2, $ml);
$pack = substr($pack, 2 + $ml);
}
close(F);
# calculate missing stuff
#
# modulus INTEGER, -- n
# publicExponent INTEGER, -- e
# privateExponent INTEGER, -- d 2
# prime1 INTEGER, -- p 4
# prime2 INTEGER, -- q 3
# exponent1 INTEGER, -- d mod (p-1)
# exponent2 INTEGER, -- d mod (q-1)
# coefficient INTEGER, -- (inverse of q) mod p
my $d = Math::BigInt->new('0x' . unpack('H*', $s[2]));
my $p = Math::BigInt->new('0x' . unpack('H*', $s[4]));
my $q = Math::BigInt->new('0x' . unpack('H*', $s[3]));
my $ex1 = $d->copy()->bmod($p->copy()->bdec());
my $ex2 = $d->copy()->bmod($q->copy()->bdec());
$ex1 = pack('H*', substr($ex1->as_hex(), 2));
$ex2 = pack('H*', substr($ex2->as_hex(), 2));

# asn1 encode
my $asn1 = '';
$asn1 .= packmpi(chr(0));
$asn1 .= packmpi($s[0]);
$asn1 .= packmpi($s[1]);
$asn1 .= packmpi($s[2]);
$asn1 .= packmpi($s[4]);
$asn1 .= packmpi($s[3]);
$asn1 .= packmpi($ex1);
$asn1 .= packmpi($ex2);
$asn1 .= packmpi($s[5]);
$asn1 = chr(0x30).packlen(length($asn1)).$asn1;

# pem encode
my $base64 = encode_base64($asn1, '');
my $pem = "-----BEGIN RSA PRIVATE KEY-----\n";
$pem .= "$_\n" for $base64 =~ /(.{1,64})/g;
$pem .= "-----END RSA PRIVATE KEY-----\n";
return $pem;
return priv2openssl_ed25519(@s) if $pkalgo == 22 && $curve eq "\x2b\x06\x01\x04\x01\xda\x47\x0f\x01";
return priv2openssl_rsa(@s) if $pkalgo == 1;
die("unsupported pubkey algorithm/curve\n");
}
die("no private key found\n");
}
Expand Down Expand Up @@ -750,16 +796,28 @@ sub cmd_keygen {
my $email = $args[3];
checkbadchar($real, 'real name');
checkbadchar($email, 'email');
die("bad type: $type\n") unless $type =~ /^(dsa|rsa)\@(1024|2048|4096)$/s;
my $length = $2;
$type = $1;
my $length;
if ($type eq 'ed25519') {
$length = 'Ed25519';
$type = 'EDDSA';
} else {
die("bad type: $type\n") unless $type =~ /^(dsa|rsa)\@(1024|2048|4096)$/s;
$length = $2;
$type = $1;
}

my $org_gnupghome = $ENV{GNUPGHOME};
my $tdir;
($tdir, $ENV{GNUPGHOME}) = prepare_tmp_gnupghome($tmpdir);

# write params file
my $batch = "Key-Type: $type\nKey-Length: $length\nKey-Usage: sign\nName-Real: $real\nName-Email: $email\nExpire-Date: ${expire}d\n%no-protection\n";
my $batch;
if ($type eq 'EDDSA') {
$batch = "Key-Type: $type\nKey-Curve: $length\n";
} else {
$batch = "Key-Type: $type\nKey-Length: $length\n";
}
$batch .= "Key-Usage: sign\nName-Real: $real\nName-Email: $email\nExpire-Date: ${expire}d\n%no-protection\n";
local *F;
open(F, ">$tdir/params") || die("$tdir/params: $!\n");
(syswrite(F, $batch) || 0) == length($batch) || die("keygen parameter write error\n");
Expand Down

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