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cvm
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Make the panel establish and use an SSH tunnel instead of using php-ssh2

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feature/node-rewrite
Sven Slootweg 11 years ago
parent 8c5b62730a
commit 1d3aa1f756
2 changed files with 233 additions and 55 deletions
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9
frontend/classes/node.php
Unescape Escape View File

@ -26,10 +26,12 @@ class Node extends CPHPDatabaseRecordClass
'PhysicalLocation' => "PhysicalLocation",
'PrivateKey' => "CustomPrivateKey",
'PublicKey' => "CustomPublicKey",
'User' => "User"
'User' => "User",
'TunnelKey' => "TunnelKey"
),
'numeric' => array(
'Port' => "Port"
'Port' => "Port",
'TunnelPort' => "TunnelPort"
),
'boolean' => array(
'HasCustomKey' => "HasCustomKey"
@ -47,6 +49,9 @@ class Node extends CPHPDatabaseRecordClass
$this->ssh->host = $this->sHostname;
$this->ssh->port = $this->sPort;
$this->ssh->user = $this->sUser;
$this->ssh->tunnel_port = $this->sTunnelPort;
$this->ssh->tunnel_key = $this->sTunnelKey;
$this->ssh->node = $this;
if($this->HasCustomKey === true)
{

279
frontend/classes/sshconnector.php
Unescape Escape View File

@ -35,15 +35,6 @@ class SshConnector extends CPHPBaseClass
{
try
{
if($this->failed == false && ($this->connected == false || $this->authenticated == false))
{
$this->Connect();
}
elseif($this->failed == true)
{
throw new SshConnectException("Previous connection attempt failed.");
}
return $this->DoCommand($command, $throw_exception);
}
catch (SshConnectException $e)
@ -78,81 +69,263 @@ class SshConnector extends CPHPBaseClass
public function Connect()
{
$fp = @fsockopen($this->host, $this->port, $errno, $errstr, 3);
if(!$fp)
/* TODO: TIME_WAIT status for a previous socket on the same port may cause issues
* when attempting to restart the command daemon. There is currently no way
* to detect this from the code, and it makes all subsequent requests fail
* (silently?) because the tunnel is available but nothing is listening on
* the other end. This kind of edge case should be detected and dealt with.
* A browser displays a 'no data received' error in this case. */
if($this->failed)
{
throw new SshConnectException("Could not connect to {$this->host}:{$this->port}: {$errstr}");
throw new SshConnectException("A previous connection attempt failed.");
}
$sHost = escapeshellarg($this->host);
$sUser = escapeshellarg($this->user);
$sPort = $this->tunnel_port = $this->node->uTunnelPort = $this->ChoosePort();
$sKeyFile = escapeshellarg($this->key);
$this->node->uTunnelKey = $this->tunnel_key = random_string(16);
$sSessionKey = escapeshellarg($this->node->uTunnelKey);
$command = "python /etc/cvm/start_tunnel.py {$sHost} {$sUser} {$sPort} {$sKeyFile} {$sSessionKey}";
$steps = array();
foreach(debug_backtrace() as $step)
{
try
{
$allargs = implode(", ", $step['args']);
}
catch (Exception $e)
{
$allargs = "[unserializable]";
}
$steps[] = "{$step['file']}:{$step['line']} => {$step['class']}{$step['type']}{$step['function']}({$allargs})";
}
fclose($fp);
cphp_debug_snapshot(array(
"action" => "start tunnel",
"db-tunnelkey" => $this->node->sTunnelKey,
"db-utunnelkey" => $this->node->uTunnelKey,
"ssh-tunnelkey" => $this->tunnel_key,
"arg-tunnelkey" => $sSessionKey,
"trace" => $steps
));
$options = array(
'hostkey' => $this->keytype
);
exec($command, $output, $returncode);
if($this->connection = @ssh2_connect($this->host, $this->port, $options))
if($returncode === 0)
{
$this->connected = true;
/* autossh returns before the SSH connection has actually been established. We'll make the
* script sleep until a connection has been established, with a timeout of 10 seconds, after
* which an exception is raised. The polling interval is 100ms. */
if(empty($this->passphrase))
$start_time = time();
while(true)
{
$result = @ssh2_auth_pubkey_file($this->connection, $this->user, $this->pubkey, $this->key);
if(time() > $start_time + 10)
{
throw new SshConnectException("The SSH tunnel could not be fully established within the timeout period.");
}
if($pollsock = @fsockopen("localhost", $this->tunnel_port, $errno, $errstr, 1))
{
/* The tunnel has been fully established. */
fclose($pollsock);
break;
}
usleep(100000);
}
else
cphp_debug_snapshot(array(
"action" => "pre insert db",
"db-tunnelkey" => $this->node->sTunnelKey,
"db-utunnelkey" => $this->node->uTunnelKey,
"ssh-tunnelkey" => $this->tunnel_key,
"arg-tunnelkey" => $sSessionKey
));
$this->node->InsertIntoDatabase();
cphp_debug_snapshot(array(
"action" => "inserted db",
"db-tunnelkey" => $this->node->sTunnelKey,
"db-utunnelkey" => $this->node->uTunnelKey,
"ssh-tunnelkey" => $this->tunnel_key,
"arg-tunnelkey" => $sSessionKey
));
return true;
}
else
{
throw new SshConnectException("Could not establish tunnel to {$this->host}:{$this->port}.");
}
}
private function ChoosePort()
{
try
{
$sPorts = array();
foreach(Node::CreateFromQuery("SELECT * FROM nodes WHERE `TunnelPort` != 0") as $node)
{
$result = @ssh2_auth_pubkey_file($this->connection, $this->user, $this->pubkey, $this->key, $this->passphrase);
$sPorts[] = $node->sTunnelPort;
$sPorts[] = $node->sTunnelPort + 1;
$sPorts[] = $node->sTunnelPort + 2;
}
if($result === true)
/* TODO: Figure out a more intelligent way of choosing ports. */
$start = max($sPorts) + 1;
}
catch (NotFoundException $e)
{
$start = 2000;
}
$current = $start;
while(true)
{
if($current > 65534)
{
throw new SshConnectException("No free tunnel ports left.");
}
if(!$this->TestPort($current))
{
$this->authenticated = true;
return true;
if(!$this->TestPort($current + 1))
{
if(!$this->TestPort($current + 2))
{
break;
}
else
{
$current = $current + 3;
}
}
else
{
$current = $current + 2;
}
}
else
{
throw new SshAuthException("Could not connect to {$this->host}:{$this->port}: Key authentication failed");
$current = $current + 1;
}
}
return $current;
}
private function TestPort($port)
{
if($testsock = @fsockopen("localhost", $port, $errno, $errstr, 1))
{
fclose($testsock);
return true;
}
else
{
throw new SshConnectException("Could not connect to {$this->host}:{$this->port}: {$error}");
return false;
}
return false;
}
private function DoCommand($command, $throw_exception)
private function DoCommand($command, $throw_exception, $allow_retry = true)
{
$command = base64_encode(json_encode($command));
$command = "{$this->helper} {$command}";
cphp_debug_snapshot(array(
"action" => "pre run command",
"db-tunnelkey" => $this->node->sTunnelKey,
"db-utunnelkey" => $this->node->uTunnelKey,
"ssh-tunnelkey" => $this->tunnel_key,
"command" => $command,
"allow-retry" => $allow_retry
));
$stream = ssh2_exec($this->connection, $command);
$error_stream = ssh2_fetch_stream($stream, SSH2_STREAM_STDERR);
$cmd = urlencode(json_encode($command));
$url = "http://localhost:{$this->tunnel_port}/?key={$this->tunnel_key}&command={$cmd}";
stream_set_blocking($stream, true);
stream_set_blocking($error_stream, true);
$result = stream_get_contents($stream);
$error = stream_get_contents($error_stream);
if(strpos($error, "No such file or directory") !== false)
$context = stream_context_create(array(
'http' => array(
'timeout' => 2.0
)
));
$response = @file($url, 0, $context);
cphp_debug_snapshot(array(
"action" => "post run command",
"db-tunnelkey" => $this->node->sTunnelKey,
"db-utunnelkey" => $this->node->uTunnelKey,
"ssh-tunnelkey" => $this->tunnel_key,
"command" => $command,
"allow-retry" => $allow_retry,
"response" => $response
));
if($response === false)
{
/* Determine why the connection failed, and what we need to do to fix it. */
if($testsock = @fsockopen("localhost", $this->tunnel_port, $errno, $errstr, 1))
{
/* The socket works fine. */
fclose($testsock);
/* Since the socket works but we can't make a request, there is most
* likely a serious problem with the command daemon (stuck, crashed,
* etc.) We'll throw an exception. TODO: Log error. */
$this->failed = true;
throw new SshCommandException("The command daemon is unavailable.");
}
else
{
/* The tunnel is gone for some reason. Either the connection broke
* and autossh is busy reconnecting, or autossh broke entirely. We
* will attempt to connect to the monitoring port to see if autossh
* is still running or not. */
if($testsock = @fsockopen("localhost", ($this->tunnel_port + 2), $errno, $errstr, 1))
{
/* The socket works fine. */
fclose($testsock);
/* Most likely autossh is very busy trying to reconnect to the node. We'll throw a
* connection exception for now. TODO: Consider waiting with a specified timeout. */
$this->failed = true;
throw new SshConnectException("The SSH connection to this node is currently unavailable.");
}
else
{
if($allow_retry)
{
$this->Connect();
$res = $this->DoCommand($command, $throw_exception, false);
}
else
{
$this->failed = true;
throw new SshConnectException("Could not connect to node.");
/* TODO: Log error, this is probably very bad. */
}
}
}
}
else
{
throw new Exception("The runhelper is not installed on the node or an error occurred.");
$response = json_decode(implode("", $response));
}
$returndata = json_decode($result);
$returndata->stderr = trim($returndata->stderr);
fclose($stream);
fclose($error_stream);
if($returndata->returncode != 0 && $throw_exception === true)
if($response->returncode != 0 && $throw_exception === true)
{
throw new SshExitException("Non-zero exit code returned: {$returndata->stderr}", $returndata->returncode);
throw new SshExitException("Non-zero exit code returned: {$response->stderr}", $response->returncode);
}
return $returndata;
return $response;
}
}

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