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SSH2: end connection faster for algorithm mismatch

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terrafrost 2020-12-07 08:00:44 -06:00
parent 0b20aff6ff
commit ee4af462b6
1 changed files with 37 additions and 36 deletions
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73
phpseclib/Net/SSH2.php
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@ -1552,6 +1552,39 @@ class Net_SSH2
user_error('No compatible key exchange algorithms found'); user_error('No compatible key exchange algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED); return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
} }
$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);
}
$mac_algorithm_out = $this->_array_intersect_first($c2s_mac_algorithms, $this->mac_algorithms_client_to_server);
if ($mac_algorithm_out === false) {
user_error('No compatible client to server message authentication algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$mac_algorithm_in = $this->_array_intersect_first($s2c_mac_algorithms, $this->mac_algorithms_server_to_client);
if ($mac_algorithm_in === false) {
user_error('No compatible server to client message authentication algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
$compression_algorithm_out = $this->_array_intersect_first($c2s_compression_algorithms, $this->compression_algorithms_client_to_server);
if ($compression_algorithm_out === false) {
user_error('No compatible client to server compression algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
//$this->decompress = $compression_algorithm_out == 'zlib';
$compression_algorithm_in = $this->_array_intersect_first($s2c_compression_algorithms, $this->compression_algorithms_client_to_server);
if ($compression_algorithm_in === false) {
user_error('No compatible server to client compression algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
//$this->compress = $compression_algorithm_in == 'zlib';
if (strpos($kex_algorithm, 'diffie-hellman-group-exchange') === 0) { if (strpos($kex_algorithm, 'diffie-hellman-group-exchange') === 0) {
$dh_group_sizes_packed = pack( $dh_group_sizes_packed = pack(
'NNN', 'NNN',
@ -1759,12 +1792,6 @@ class Net_SSH2
$this->session_id = $this->exchange_hash; $this->session_id = $this->exchange_hash;
} }
$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 $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
switch ($server_host_key_algorithm) { switch ($server_host_key_algorithm) {
case 'ssh-dss': case 'ssh-dss':
$expected_key_format = 'ssh-dss'; $expected_key_format = 'ssh-dss';
@ -1884,14 +1911,8 @@ class Net_SSH2
$this->decrypt->decrypt(str_repeat("\0", 1536)); $this->decrypt->decrypt(str_repeat("\0", 1536));
} }
$mac_algorithm = $this->_array_intersect_first($c2s_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_algorithm == 'none' $createKeyLength = 0; // ie. $mac_algorithm == 'none'
switch ($mac_algorithm) { switch ($mac_algorithm_out) {
case 'hmac-sha2-256': case 'hmac-sha2-256':
$this->hmac_create = new Crypt_Hash('sha256'); $this->hmac_create = new Crypt_Hash('sha256');
$createKeyLength = 32; $createKeyLength = 32;
@ -1912,17 +1933,11 @@ class Net_SSH2
$this->hmac_create = new Crypt_Hash('md5-96'); $this->hmac_create = new Crypt_Hash('md5-96');
$createKeyLength = 16; $createKeyLength = 16;
} }
$this->hmac_create->name = $mac_algorithm; $this->hmac_create->name = $mac_algorithm_out;
$mac_algorithm = $this->_array_intersect_first($s2c_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; $checkKeyLength = 0;
$this->hmac_size = 0; $this->hmac_size = 0;
switch ($mac_algorithm) { switch ($mac_algorithm_in) {
case 'hmac-sha2-256': case 'hmac-sha2-256':
$this->hmac_check = new Crypt_Hash('sha256'); $this->hmac_check = new Crypt_Hash('sha256');
$checkKeyLength = 32; $checkKeyLength = 32;
@ -1948,7 +1963,7 @@ class Net_SSH2
$checkKeyLength = 16; $checkKeyLength = 16;
$this->hmac_size = 12; $this->hmac_size = 12;
} }
$this->hmac_check->name = $mac_algorithm; $this->hmac_check->name = $mac_algorithm_in;
$key = $kexHash->hash($keyBytes . $this->exchange_hash . 'E' . $this->session_id); $key = $kexHash->hash($keyBytes . $this->exchange_hash . 'E' . $this->session_id);
while ($createKeyLength > strlen($key)) { while ($createKeyLength > strlen($key)) {
@ -1962,20 +1977,6 @@ class Net_SSH2
} }
$this->hmac_check->setKey(substr($key, 0, $checkKeyLength)); $this->hmac_check->setKey(substr($key, 0, $checkKeyLength));
$compression_algorithm = $this->_array_intersect_first($c2s_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->decompress = $compression_algorithm == 'zlib';
$compression_algorithm = $this->_array_intersect_first($s2c_compression_algorithms, $this->compression_algorithms_client_to_server);
if ($compression_algorithm === false) {
user_error('No compatible server to client compression algorithms found');
return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
}
//$this->compress = $compression_algorithm == 'zlib';
return true; return true;
} }