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-rwxr-xr-xsrc/keytrans/pem2openpgp62
1 files changed, 55 insertions, 7 deletions
diff --git a/src/keytrans/pem2openpgp b/src/keytrans/pem2openpgp
index ae7c91f..40188c7 100755
--- a/src/keytrans/pem2openpgp
+++ b/src/keytrans/pem2openpgp
@@ -288,7 +288,38 @@ sub mpi_pack {
return pack('n', $mpilen).$val;
}
-# pull an OpenPGP-specified MPI off of a given stream.
+# 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;
@@ -527,10 +558,18 @@ 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);
@@ -583,8 +622,6 @@ sub openpgp2ssh {
$tag == $packet_types->{pub_subkey} ||
$tag == $packet_types->{seckey} ||
$tag == $packet_types->{sec_subkey}) {
- printf(STDERR "Packet type %d\n", $tag);
-
my $ver;
read($instr, $ver, 1) or die "could not read key version\n";
$ver = ord($ver);
@@ -610,8 +647,17 @@ sub openpgp2ssh {
my $pubkey = Crypt::OpenSSL::RSA->new_key_from_parameters($modulus, $exponent);
my $foundfpr = fingerprint($pubkey, $timestamp);
-
- printf(STDERR "key fpr: %s\n", Crypt::OpenSSL::Bignum->new_from_bin($foundfpr)->to_hex());
+
+ 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}) {
@@ -625,7 +671,9 @@ sub openpgp2ssh {
}
}
- print $tag;
+ if (defined($key)) {
+ return "ssh-rsa ".encode_base64(openssh_pubkey_pack($key), '');
+ }
}
@@ -662,7 +710,7 @@ for (basename($0)) {
my $instream;
open($instream,'-');
binmode($instream, ":bytes");
- openpgp2ssh($instream, $fpr);
+ print openpgp2ssh($instream, $fpr);
}
else {
die "Unrecognized keytrans call.\n";