Undefined Array Key WARNING

[vansari]

Hi,

is it possible that we can check if the key exists or can we coalesce to false if it doesnt exists?

phpseclib/phpseclib/Net/SSH2.php

Line 4267 in 7181378

if (!$this->window_size_client_to_server[$client_channel]) {

[terrafrost]

Before considering your PR's I'd like to better understand why this is needed. Can you tell me what version of phpseclib you're using and could you provide the full log files? You can get them by doing define('NET_SSH2_LOGGING', 2) at the top of your file and then echo $ssh->getLog(); after you get the error.

The thing is... when phpseclib opens a channel the server should respond with an OPEN_CONFIRMATION packet that should set that variable:

phpseclib/phpseclib/Net/SSH2.php

Lines 3902 to 3913 in a10a3b8

	case NET_SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
	list(
	$this->server_channels[$channel],
	$window_size,
	$this->packet_size_client_to_server[$channel]
	) = Strings::unpackSSH2('NNN', $response);
	if ($window_size < 0) {
	$window_size &= 0x7FFFFFFF;
	$window_size += 0x80000000;
	}
	$this->window_size_client_to_server[$channel] = $window_size;

If the server tries to open a channel on the client (phpseclib) then phpseclib will respond with an OPEN_FAILURE response unless the CHANNEL_OPEN request is for auth-agent or auth-agent@openssh.com.

If phpseclib is sending channel data for a channel that has not been opened then that's a bug which this code (1) doesn't fix and (2) sweeps under the rug and makes it harder to spot.

So instead of trying to address the symptoms I'd rather we consider the root cause.