X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=src%2Fkeytrans%2Fpem2openpgp;h=637eba2a225fecbc399a64e3ad6433461b63a36c;hb=3f5960cf4ba2f938c677c27e3296e6feae2f56aa;hp=f6e2d4f33d3f79f2cbc7d59fa61dba06936a8dbb;hpb=04e7cb84fcb8a16444eba640998e08bc1d39f60b;p=monkeysphere.git diff --git a/src/keytrans/pem2openpgp b/src/keytrans/pem2openpgp index f6e2d4f..637eba2 100755 --- a/src/keytrans/pem2openpgp +++ b/src/keytrans/pem2openpgp @@ -4,6 +4,10 @@ # User ID as the first argument, and generate an OpenPGP certificate # from it. +# Usage: + +# pem2openpgp 'ssh://'$(hostname -f) < /etc/ssh/ssh_host_rsa_key | gpg --import + # Authors: # Jameson Rollins # Daniel Kahn Gillmor @@ -23,6 +27,11 @@ 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 ? + # make an old-style packet out of the given packet type and body. # old-style (see RFC 4880 section 4.2) sub make_packet { @@ -74,7 +83,7 @@ sub mpi_pack { } # FIXME: genericize this to accept either RSA or DSA keys: -sub make_rsa_key_body { +sub make_rsa_pub_key_body { my $key = shift; my $timestamp = shift; @@ -93,12 +102,135 @@ sub fingerprint { my $key = shift; my $timestamp = shift; - my $rsabody = make_rsa_key_body($key, $timestamp); + my $rsabody = make_rsa_pub_key_body($key, $timestamp); - return Digest::SHA1::sha1_hex(pack('Cn', 0x99, length($rsabody)).$rsabody); + return Digest::SHA1::sha1(pack('Cn', 0x99, length($rsabody)).$rsabody); } -my $holdTerminator = $/; +# FIXME: replace the opaque numbers below with +# semantically-meaningful references based on these tables. + +# 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 5.2.3.1 +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 + }; + +# we're just not dealing with newline business right now. slurp in +# the whole file. undef $/; my $buf = ; @@ -106,55 +238,76 @@ my $buf = ; my $rsa = Crypt::OpenSSL::RSA->new_private_key($buf); $rsa->use_sha1_hash(); -$rsa->use_no_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"; } -my $uid = 'fake key (do not use) '; - - - my $version = pack('C', 4); # strong assertion of identity: -my $sigtype = pack('C', 0x13); +my $sigtype = pack('C', $sig_types->{positive_certification}); # RSA -my $pubkey_algo = pack('C', 1); +my $pubkey_algo = pack('C', $asym_algos->{rsa}); # SHA1 -my $hash_algo = pack('C', 2); +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. How can we prevent +# this? +# could an environment variable (if set) override the current time? +my $timestamp = time(); -my $timestamp = 1231003584; +my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp); -my $creation_time_packet = pack('CCN', 5, 2, $timestamp); +# FIXME: HARDCODED: what if someone wants to select a different set of +# usage flags? For now, we do only authentication. +my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $usage_flags->{authenticate}); -# usage: signing and certification: -my $flags = 0x03; -my $usage_packet = pack('CCC', 2, 27, $flags); - -# expire in 2 days: +# FIXME: HARDCODED: how should we determine how far off to set the +# expiration date? default is to expire in 2 days, which is insanely +# short (but good for testing). my $expires_in = 86400*2; -my $expiration_packet = pack('CCN', 5, 9, $expires_in); +my $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, 11, 9, 8, 7, 3, 2); +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, 21, 2, 8, 3); +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, 22, 2, 3, 1); +my $pref_zip_algos = pack('CCCCC', 4, $subpacket_types->{preferred_compression}, + $zips->{zlib}, + $zips->{bzip2}, + $zips->{zip} + ); # we support the MDC feature: -my $features = pack('CCC', 2, 30, 1); +my $feature_subpacket = pack('CCC', 2, $subpacket_types->{features}, + $features->{mdc}); # keyserver preference: only owner modify (???): -my $keyserver_pref = pack('CCC', 2, 23, 0x80); +my $keyserver_pref = pack('CCC', 2, $subpacket_types->{keyserver_prefs}, + $keyserver_prefs->{nomodify}); my $subpackets_to_be_hashed = $creation_time_packet. @@ -163,7 +316,7 @@ my $subpackets_to_be_hashed = $pref_sym_algos. $pref_hash_algos. $pref_zip_algos. - $features. + $feature_subpacket. $keyserver_pref; my $subpacket_octets = pack('n', length($subpackets_to_be_hashed)); @@ -176,13 +329,12 @@ my $sig_data_to_be_hashed = $subpacket_octets. $subpackets_to_be_hashed; -my $pubkey = make_rsa_key_body($rsa, $timestamp); +my $pubkey = make_rsa_pub_key_body($rsa, $timestamp); -#open(KEYFILE, "{pubkey}, $pubkey); -# take the last 16 characters of the fingerprint as the keyid: -my $keyid = substr(fingerprint($rsa, $timestamp), 40 - 16, 16); +# 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: @@ -203,7 +355,7 @@ my $datatosign = my $data_hash = Digest::SHA1::sha1_hex($datatosign); -my $issuer_packet = pack('CCH16', 9, 16, $keyid); +my $issuer_packet = pack('CCa8', 9, $subpacket_types->{issuer}, $keyid); my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign)); @@ -214,8 +366,9 @@ my $sig_body = pack('n', hex(substr($data_hash, 0, 4))). mpi_pack($sig); -print make_packet(6, $pubkey); -print make_packet(13, $uid); -print make_packet(2, $sig_body); +print + make_packet($packet_types->{pubkey}, $pubkey). + make_packet($packet_types->{uid}, $uid). + make_packet($packet_types->{sig}, $sig_body); + -$/ = $holdTerminator;