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SSH2: Introduce _array_intersect_first function. 

+ No more empty for-loop bodies
+ No more counting variables $i leaked into outer context
+ No more unintuitive $i == count(...) comparisons
+ No more array / hash table access of the form $kex_algorithms[$i]
- Function call overhead; not in the performance critical path, though.
This commit is contained in:
Andreas Fischer 2015-07-17 18:20:42 +02:00
parent e251f6c372
commit 1473da35e6
1 changed files with 50 additions and 45 deletions
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95
phpseclib/Net/SSH2.php
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@ -1357,16 +1357,9 @@ class Net_SSH2
// here ends the second place.
// we need to decide upon the symmetric encryption algorithms before we do the diffie-hellman key exchange
for ($i = 0; $i < count($encryption_algorithms) && !in_array($encryption_algorithms[$i], $this->encryption_algorithms_server_to_client); $i++) {
}
if ($i == count($encryption_algorithms)) {
user_error('No compatible server to client encryption algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
// we don't initialize any crypto-objects, yet - we do that, later. for now, we need the lengths to make the
// diffie-hellman key exchange as fast as possible
$decrypt = $encryption_algorithms[$i];
$decrypt = $this->_array_intersect_first($encryption_algorithms, $this->encryption_algorithms_server_to_client);
switch ($decrypt) {
case '3des-cbc':
case '3des-ctr':
@ -1402,16 +1395,13 @@ class Net_SSH2
break;
case 'none':
$decryptKeyLength = 0;
break;
default:
user_error('No compatible server to client encryption algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
for ($i = 0; $i < count($encryption_algorithms) && !in_array($encryption_algorithms[$i], $this->encryption_algorithms_client_to_server); $i++) {
}
if ($i == count($encryption_algorithms)) {
user_error('No compatible client to server encryption algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$encrypt = $encryption_algorithms[$i];
$encrypt = $this->_array_intersect_first($encryption_algorithms, $this->encryption_algorithms_client_to_server);
switch ($encrypt) {
case '3des-cbc':
case '3des-ctr':
@ -1447,20 +1437,21 @@ class Net_SSH2
break;
case 'none':
$encryptKeyLength = 0;
break;
default:
user_error('No compatible client to server encryption algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$keyLength = $decryptKeyLength > $encryptKeyLength ? $decryptKeyLength : $encryptKeyLength;
// through diffie-hellman key exchange a symmetric key is obtained
for ($i = 0; $i < count($kex_algorithms) && !in_array($kex_algorithms[$i], $this->kex_algorithms);
$i++) {
}
if ($i == count($kex_algorithms)) {
$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_algorithms[$i], 'diffie-hellman-group-exchange') === 0) {
if (strpos($kex_algorithm, 'diffie-hellman-group-exchange') === 0) {
$dh_group_sizes_packed = pack(
'NNN',
$this->kex_dh_group_size_min,
@ -1507,7 +1498,7 @@ class Net_SSH2
$clientKexInitMessage = NET_SSH2_MSG_KEXDH_GEX_INIT;
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_GEX_REPLY;
} else {
switch ($kex_algorithms[$i]) {
switch ($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':
@ -1537,7 +1528,7 @@ class Net_SSH2
$serverKexReplyMessage = NET_SSH2_MSG_KEXDH_REPLY;
}
switch ($kex_algorithms[$i]) {
switch ($kex_algorithm) {
case 'diffie-hellman-group-exchange-sha256':
$kexHash = new Crypt_Hash('sha256');
break;
@ -1626,14 +1617,13 @@ class Net_SSH2
$this->session_id = $this->exchange_hash;
}
for ($i = 0; $i < count($server_host_key_algorithms) && !in_array($server_host_key_algorithms[$i], $this->server_host_key_algorithms); $i++) {
}
if ($i == count($server_host_key_algorithms)) {
$server_host_key_algorithm = $this->_array_intersect_first($server_host_key_algorithms, $this->server_host_key_algorithms);
if ($server_host_key_algorithm === false) {
user_error('No compatible server host key algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
if ($public_key_format != $server_host_key_algorithms[$i] || $this->signature_format != $server_host_key_algorithms[$i]) {
if ($public_key_format != $server_host_key_algorithm || $this->signature_format != $server_host_key_algorithm) {
user_error('Server Host Key Algorithm Mismatch');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
@ -1871,15 +1861,14 @@ class Net_SSH2
$this->decrypt->decrypt(str_repeat("\0", 1536));
}
for ($i = 0; $i < count($mac_algorithms) && !in_array($mac_algorithms[$i], $this->mac_algorithms_client_to_server); $i++) {
}
if ($i == count($mac_algorithms)) {
$mac_algorithm = $this->_array_intersect_first($mac_algorithms, $this->mac_algorithms_client_to_server);
if ($mac_algorithm === false) {
user_error('No compatible client to server message authentication algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$createKeyLength = 0; // ie. $mac_algorithms[$i] == 'none'
switch ($mac_algorithms[$i]) {
$createKeyLength = 0; // ie. $mac_algorithm == 'none'
switch ($mac_algorithm) {
case 'hmac-sha2-256':
$this->hmac_create = new Crypt_Hash('sha256');
$createKeyLength = 32;
@ -1901,16 +1890,15 @@ class Net_SSH2
$createKeyLength = 16;
}
for ($i = 0; $i < count($mac_algorithms) && !in_array($mac_algorithms[$i], $this->mac_algorithms_server_to_client); $i++) {
}
if ($i == count($mac_algorithms)) {
$mac_algorithm = $this->_array_intersect_first($mac_algorithms, $this->mac_algorithms_server_to_client);
if ($mac_algorithm === false) {
user_error('No compatible server to client message authentication algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$checkKeyLength = 0;
$this->hmac_size = 0;
switch ($mac_algorithms[$i]) {
switch ($mac_algorithm) {
case 'hmac-sha2-256':
$this->hmac_check = new Crypt_Hash('sha256');
$checkKeyLength = 32;
@ -1949,21 +1937,19 @@ class Net_SSH2
}
$this->hmac_check->setKey(substr($key, 0, $checkKeyLength));
for ($i = 0; $i < count($compression_algorithms) && !in_array($compression_algorithms[$i], $this->compression_algorithms_server_to_client); $i++) {
}
if ($i == count($compression_algorithms)) {
$compression_algorithm = $this->_array_intersect_first($compression_algorithms, $this->compression_algorithms_server_to_client);
if ($compression_algorithm === false) {
user_error('No compatible server to client compression algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$this->decompress = $compression_algorithms[$i] == 'zlib';
$this->decompress = $compression_algorithm == 'zlib';
for ($i = 0; $i < count($compression_algorithms) && !in_array($compression_algorithms[$i], $this->compression_algorithms_client_to_server); $i++) {
}
if ($i == count($compression_algorithms)) {
$compression_algorithm = $this->_array_intersect_first($compression_algorithms, $this->compression_algorithms_client_to_server);
if ($compression_algorithm === false) {
user_error('No compatible client to server compression algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$this->compress = $compression_algorithms[$i] == 'zlib';
$this->compress = $compression_algorithm == 'zlib';
return true;
}
@ -3877,6 +3863,25 @@ class Net_SSH2
}
}
/**
* Returns the first value of the intersection of two arrays or false if
* the intersection is empty. The order is defined by the first parameter.
*
* @param Array $array1
* @param Array $array2
* @return Mixed False if intersection is empty, else intersected value.
* @access private
*/
function _array_intersect_first($array1, $array2)
{
foreach ($array1 as $value) {
if (in_array($value, $array2)) {
return $value;
}
}
return false;
}
/**
* Returns all errors
*