SSH2: Add support for curve25519-sha256@libssh.org.txt via libsodium-php.

This commit is contained in:
Andreas Fischer 2015-07-23 03:02:28 +02:00
parent 27be192189
commit 58f8affcad
4 changed files with 147 additions and 104 deletions

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@ -55,6 +55,7 @@
"squizlabs/php_codesniffer": "~2.0"
},
"suggest": {
"ext-libsodium": "SSH2/SFTP can make use of some algorithms provided by the libsodium-php extension.",
"ext-mcrypt": "Install the Mcrypt extension in order to speed up a wide variety of cryptographic operations.",
"ext-gmp": "Install the GMP (GNU Multiple Precision) extension in order to speed up arbitrary precision integer arithmetic operations."
},

2
composer.lock generated
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@ -4,7 +4,7 @@
"Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
"This file is @generated automatically"
],
"hash": "a8adabfa04c250bbec41c87f79a59b31",
"hash": "b24ab20be15b6312e532ee2ffa18d5fa",
"packages": [],
"packages-dev": [
{

View File

@ -953,7 +953,10 @@ class SSH2
31 => 'NET_SSH2_MSG_KEXDH_GEX_GROUP',
32 => 'NET_SSH2_MSG_KEXDH_GEX_INIT',
33 => 'NET_SSH2_MSG_KEXDH_GEX_REPLY',
34 => 'NET_SSH2_MSG_KEXDH_GEX_REQUEST')
34 => 'NET_SSH2_MSG_KEXDH_GEX_REQUEST'),
// RFC 5656 - Elliptic Curves (for curve25519-sha256@libssh.org)
array(30 => 'NET_SSH2_MSG_KEX_ECDH_INIT',
31 => 'NET_SSH2_MSG_KEX_ECDH_REPLY')
);
if (is_resource($host)) {
@ -1110,9 +1113,13 @@ class SSH2
*/
function _generate_identifier()
{
$identifier = 'SSH-2.0-phpseclib_0.3';
$identifier = 'SSH-2.0-phpseclib_2.0';
$ext = array();
if (extension_loaded('libsodium')) {
$ext[] = 'libsodium';
}
if (extension_loaded('openssl')) {
$ext[] = 'openssl';
} elseif (extension_loaded('mcrypt')) {
@ -1141,11 +1148,24 @@ class SSH2
function _key_exchange($kexinit_payload_server)
{
static $kex_algorithms = array(
// Elliptic Curve Diffie-Hellman Key Agreement (ECDH) using
// Curve25519. See doc/curve25519-sha256@libssh.org.txt in the
// libssh repository for more information.
'curve25519-sha256@libssh.org',
// Diffie-Hellman Key Agreement (DH) using integer modulo prime
// groups.
'diffie-hellman-group1-sha1', // REQUIRED
'diffie-hellman-group14-sha1', // REQUIRED
'diffie-hellman-group-exchange-sha1', // RFC 4419
'diffie-hellman-group-exchange-sha256', // RFC 4419
);
if (!class_exists('\Sodium')) {
$kex_algorithms = array_diff(
$kex_algorithms,
array('curve25519-sha256@libssh.org')
);
}
static $server_host_key_algorithms = array(
'ssh-rsa', // RECOMMENDED sign Raw RSA Key
@ -1359,115 +1379,124 @@ class SSH2
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$keyLength = $decryptKeyLength > $encryptKeyLength ? $decryptKeyLength : $encryptKeyLength;
// through diffie-hellman key exchange a symmetric key is obtained
$kex_algorithm = $this->_array_intersect_first($kex_algorithms, $this->kex_algorithms);
if ($kex_algorithm === false) {
user_error('No compatible key exchange algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
if (strpos($kex_algorithm, 'diffie-hellman-group-exchange') === 0) {
$dh_group_sizes_packed = pack(
'NNN',
$this->kex_dh_group_size_min,
$this->kex_dh_group_size_preferred,
$this->kex_dh_group_size_max
);
$packet = pack(
'Ca*',
NET_SSH2_MSG_KEXDH_GEX_REQUEST,
$dh_group_sizes_packed
);
if (!$this->_send_binary_packet($packet)) {
return false;
}
$response = $this->_get_binary_packet();
if ($response === false) {
user_error('Connection closed by server');
return false;
}
extract(unpack('Ctype', $this->_string_shift($response, 1)));
if ($type != NET_SSH2_MSG_KEXDH_GEX_GROUP) {
user_error('Expected SSH_MSG_KEX_DH_GEX_GROUP');
return false;
}
// Only relevant in diffie-hellman-group-exchange-sha{1,256}, otherwise empty.
$exchange_hash_rfc4419 = '';
extract(unpack('NprimeLength', $this->_string_shift($response, 4)));
$primeBytes = $this->_string_shift($response, $primeLength);
$prime = new BigInteger($primeBytes, -256);
extract(unpack('NgLength', $this->_string_shift($response, 4)));
$gBytes = $this->_string_shift($response, $gLength);
$g = new BigInteger($gBytes, -256);
$exchange_hash_rfc4419 = pack(
'a*Na*Na*',
$dh_group_sizes_packed,
$primeLength,
$primeBytes,
$gLength,
$gBytes
);
$clientKexInitMessage = NET_SSH2_MSG_KEXDH_GEX_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_GEX_REPLY;
if ($kex_algorithm === 'curve25519-sha256@libssh.org') {
$x = Random::string(32);
$eBytes = \Sodium::crypto_box_publickey_from_secretkey($x);
$clientKexInitMessage = NET_SSH2_MSG_KEX_ECDH_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEX_ECDH_REPLY;
$kexHash = new Hash('sha256');
} else {
switch ($kex_algorithm) {
// see http://tools.ietf.org/html/rfc2409#section-6.2 and
// http://tools.ietf.org/html/rfc2412, appendex E
case 'diffie-hellman-group1-sha1':
$prime = 'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74' .
'020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437' .
'4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED' .
'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF';
break;
// see http://tools.ietf.org/html/rfc3526#section-3
case 'diffie-hellman-group14-sha1':
$prime = 'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74' .
'020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437' .
'4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED' .
'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF05' .
'98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB' .
'9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B' .
'E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718' .
'3995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF';
break;
if (strpos($kex_algorithm, 'diffie-hellman-group-exchange') === 0) {
$dh_group_sizes_packed = pack(
'NNN',
$this->kex_dh_group_size_min,
$this->kex_dh_group_size_preferred,
$this->kex_dh_group_size_max
);
$packet = pack(
'Ca*',
NET_SSH2_MSG_KEXDH_GEX_REQUEST,
$dh_group_sizes_packed
);
if (!$this->_send_binary_packet($packet)) {
return false;
}
$response = $this->_get_binary_packet();
if ($response === false) {
user_error('Connection closed by server');
return false;
}
extract(unpack('Ctype', $this->_string_shift($response, 1)));
if ($type != NET_SSH2_MSG_KEXDH_GEX_GROUP) {
user_error('Expected SSH_MSG_KEX_DH_GEX_GROUP');
return false;
}
extract(unpack('NprimeLength', $this->_string_shift($response, 4)));
$primeBytes = $this->_string_shift($response, $primeLength);
$prime = new BigInteger($primeBytes, -256);
extract(unpack('NgLength', $this->_string_shift($response, 4)));
$gBytes = $this->_string_shift($response, $gLength);
$g = new BigInteger($gBytes, -256);
$exchange_hash_rfc4419 = pack(
'a*Na*Na*',
$dh_group_sizes_packed,
$primeLength,
$primeBytes,
$gLength,
$gBytes
);
$clientKexInitMessage = NET_SSH2_MSG_KEXDH_GEX_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_GEX_REPLY;
} else {
switch ($kex_algorithm) {
// see http://tools.ietf.org/html/rfc2409#section-6.2 and
// http://tools.ietf.org/html/rfc2412, appendex E
case 'diffie-hellman-group1-sha1':
$prime = 'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74' .
'020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437' .
'4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED' .
'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF';
break;
// see http://tools.ietf.org/html/rfc3526#section-3
case 'diffie-hellman-group14-sha1':
$prime = 'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74' .
'020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437' .
'4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED' .
'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF05' .
'98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB' .
'9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B' .
'E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718' .
'3995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF';
break;
}
// For both diffie-hellman-group1-sha1 and diffie-hellman-group14-sha1
// the generator field element is 2 (decimal) and the hash function is sha1.
$g = new BigInteger(2);
$prime = new BigInteger($prime, 16);
$clientKexInitMessage = NET_SSH2_MSG_KEXDH_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_REPLY;
}
// For both diffie-hellman-group1-sha1 and diffie-hellman-group14-sha1
// the generator field element is 2 (decimal) and the hash function is sha1.
$g = new BigInteger(2);
$prime = new BigInteger($prime, 16);
$exchange_hash_rfc4419 = '';
$clientKexInitMessage = NET_SSH2_MSG_KEXDH_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_REPLY;
switch ($kex_algorithm) {
case 'diffie-hellman-group-exchange-sha256':
$kexHash = new Hash('sha256');
break;
default:
$kexHash = new Hash('sha1');
}
/* To increase the speed of the key exchange, both client and server may
reduce the size of their private exponents. It should be at least
twice as long as the key material that is generated from the shared
secret. For more details, see the paper by van Oorschot and Wiener
[VAN-OORSCHOT].
-- http://tools.ietf.org/html/rfc4419#section-6.2 */
$one = new BigInteger(1);
$keyLength = min($kexHash->getLength(), max($encryptKeyLength, $decryptKeyLength));
$max = $one->bitwise_leftShift(16 * $keyLength); // 2 * 8 * $keyLength
$max = $max->subtract($one);
$x = $one->random($one, $max);
$e = $g->modPow($x, $prime);
$eBytes = $e->toBytes(true);
}
switch ($kex_algorithm) {
case 'diffie-hellman-group-exchange-sha256':
$kexHash = new Hash('sha256');
break;
default:
$kexHash = new Hash('sha1');
}
/* To increase the speed of the key exchange, both client and server may
reduce the size of their private exponents. It should be at least
twice as long as the key material that is generated from the shared
secret. For more details, see the paper by van Oorschot and Wiener
[VAN-OORSCHOT].
-- http://tools.ietf.org/html/rfc4419#section-6.2 */
$one = new BigInteger(1);
$keyLength = min($keyLength, $kexHash->getLength());
$max = $one->bitwise_leftShift(16 * $keyLength); // 2 * 8 * $keyLength
$max = $max->subtract($one);
$x = $one->random($one, $max);
$e = $g->modPow($x, $prime);
$eBytes = $e->toBytes(true);
$data = pack('CNa*', $clientKexInitMessage, strlen($eBytes), $eBytes);
if (!$this->_send_binary_packet($data)) {
@ -1495,7 +1524,6 @@ class SSH2
$temp = unpack('Nlength', $this->_string_shift($response, 4));
$fBytes = $this->_string_shift($response, $temp['length']);
$f = new BigInteger($fBytes, -256);
$temp = unpack('Nlength', $this->_string_shift($response, 4));
$this->signature = $this->_string_shift($response, $temp['length']);
@ -1503,7 +1531,17 @@ class SSH2
$temp = unpack('Nlength', $this->_string_shift($this->signature, 4));
$this->signature_format = $this->_string_shift($this->signature, $temp['length']);
$key = $f->modPow($x, $prime);
if ($kex_algorithm === 'curve25519-sha256@libssh.org') {
if (strlen($fBytes) !== 32) {
user_error('Received curve25519 public key of invalid length.');
return false;
}
$key = new BigInteger(\Sodium::crypto_scalarmult($x, $fBytes), 256);
\Sodium::sodium_memzero($x);
} else {
$f = new BigInteger($fBytes, -256);
$key = $f->modPow($x, $prime);
}
$keyBytes = $key->toBytes(true);
$this->exchange_hash = pack(

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@ -39,7 +39,11 @@ class Unit_Net_SSH2Test extends PhpseclibTestCase
public function testGenerateIdentifier()
{
$identifier = $this->createSSHMock()->_generate_identifier();
$this->assertStringStartsWith('SSH-2.0-phpseclib_0.3', $identifier);
$this->assertStringStartsWith('SSH-2.0-phpseclib_2.0', $identifier);
if (extension_loaded('libsodium')) {
$this->assertContains('libsodium', $identifier);
}
if (extension_loaded('openssl')) {
$this->assertContains('openssl', $identifier);