Merge branch '3.0-openchannel' into master-openchannel

phpseclib/Net/SFTP.php

@@ -351,20 +351,7 @@ class SFTP extends SSH2
     {
         $this->window_size_server_to_client[self::CHANNEL] = $this->window_size;
 
-        $packet = Strings::packSSH2(
+        $response = $this->openChannel(self::CHANNEL, true);
-            'CsN3',
-            SSH2MessageType::CHANNEL_OPEN,
-            'session',
-            self::CHANNEL,
-            $this->window_size,
-            0x4000
-        );
-
-        $this->send_binary_packet($packet);
-
-        $this->channel_status[self::CHANNEL] = SSH2MessageType::CHANNEL_OPEN;
-
-        $response = $this->get_channel_packet(self::CHANNEL, true);
         if ($response === true && $this->isTimeout()) {
             return false;
         }

phpseclib/Net/SSH2.php

@@ -922,6 +922,21 @@ class SSH2
      */
     private bool $smartMFA = true;
 
+    /**
+     * How many channels are currently opened
+     *
+     * @var int
+     */
+    private $channelCount = 0;
+
+    /**
+     * Does the server support multiple channels? If not then error out
+     * when multiple channels are attempted to be opened
+     *
+     * @var bool
+     */
+    private $errorOnMultipleChannels;
+
     /**
      * Default Constructor.
      *
@@ -1123,6 +1138,18 @@ class SSH2
             throw new UnableToConnectException("Cannot connect to SSH $matches[3] servers");
         }
 
+        // Ubuntu's OpenSSH from 5.8 to 6.9 didn't work with multiple channels. see
+        // https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/1334916 for more info.
+        // https://lists.ubuntu.com/archives/oneiric-changes/2011-July/005772.html discusses
+        // when consolekit was incorporated.
+        // https://marc.info/?l=openssh-unix-dev&m=163409903417589&w=2 discusses some of the
+        // issues with how Ubuntu incorporated consolekit
+        $pattern = '#^SSH-2\.0-OpenSSH_([\d.]+)[^ ]* Ubuntu-.*$#';
+        $match = preg_match($pattern, $this->server_identifier, $matches);
+        $match = $match && version_compare('5.8', $matches[1], '<=');
+        $match = $match && version_compare('6.9', $matches[1], '>=');
+        $this->errorOnMultipleChannels = $match;
+
         if (!$this->send_id_string_first) {
             fwrite($this->fsock, $this->identifier . "\r\n");
         }
@@ -2432,28 +2459,7 @@ class SSH2
             throw new RuntimeException('If you want to run multiple exec()\'s you will need to disable (and re-enable if appropriate) a PTY for each one.');
         }
 
-        // RFC4254 defines the (client) window size as "bytes the other party can send before it must wait for the window to
+        $this->openChannel(self::CHANNEL_EXEC);
-        // be adjusted".  0x7FFFFFFF is, at 2GB, the max size.  technically, it should probably be decremented, but,
-        // honestly, if you're transferring more than 2GB, you probably shouldn't be using phpseclib, anyway.
-        // see http://tools.ietf.org/html/rfc4254#section-5.2 for more info
-        $this->window_size_server_to_client[self::CHANNEL_EXEC] = $this->window_size;
-        // 0x8000 is the maximum max packet size, per http://tools.ietf.org/html/rfc4253#section-6.1, although since PuTTy
-        // uses 0x4000, that's what will be used here, as well.
-        $packet_size = 0x4000;
-
-        $packet = Strings::packSSH2(
-            'CsN3',
-            MessageType::CHANNEL_OPEN,
-            'session',
-            self::CHANNEL_EXEC,
-            $this->window_size_server_to_client[self::CHANNEL_EXEC],
-            $packet_size
-        );
-        $this->send_binary_packet($packet);
-
-        $this->channel_status[self::CHANNEL_EXEC] = MessageType::CHANNEL_OPEN;
-
-        $this->get_channel_packet(self::CHANNEL_EXEC);
 
         if ($this->request_pty === true) {
             $terminal_modes = pack('C', TerminalMode::TTY_OP_END);
@@ -2533,6 +2539,42 @@ class SSH2
         }
     }
 
+    /**
+     * Opens a channel
+     */
+    protected function openChannel(string $channel, bool $skip_extended = false): bool
+    {
+        $this->channelCount++;
+
+        if ($this->channelCount > 1 && $this->errorOnMultipleChannels) {
+            throw new \RuntimeException("Ubuntu's OpenSSH from 5.8 to 6.9 doesn't work with multiple channels");
+        }
+
+        // RFC4254 defines the (client) window size as "bytes the other party can send before it must wait for the window to
+        // be adjusted".  0x7FFFFFFF is, at 2GB, the max size.  technically, it should probably be decremented, but,
+        // honestly, if you're transferring more than 2GB, you probably shouldn't be using phpseclib, anyway.
+        // see http://tools.ietf.org/html/rfc4254#section-5.2 for more info
+        $this->window_size_server_to_client[$channel] = $this->window_size;
+        // 0x8000 is the maximum max packet size, per http://tools.ietf.org/html/rfc4253#section-6.1, although since PuTTy
+        // uses 0x4000, that's what will be used here, as well.
+        $packet_size = 0x4000;
+
+        $packet = Strings::packSSH2(
+            'CsN3',
+            SSH2MessageType::CHANNEL_OPEN,
+            'session',
+            $channel,
+            $this->window_size_server_to_client[$channel],
+            $packet_size
+        );
+
+        $this->send_binary_packet($packet);
+
+        $this->channel_status[$channel] = SSH2MessageType::CHANNEL_OPEN;
+
+        return $this->get_channel_packet($channel, $skip_extended);
+    }
+
     /**
      * Creates an interactive shell
      *
@@ -2556,23 +2598,7 @@ class SSH2
             throw new InsufficientSetupException('Operation disallowed prior to login()');
         }
 
-        $this->window_size_server_to_client[self::CHANNEL_SHELL] = $this->window_size;
+        $this->openChannel(self::CHANNEL_SHELL);
-        $packet_size = 0x4000;
-
-        $packet = Strings::packSSH2(
-            'CsN3',
-            MessageType::CHANNEL_OPEN,
-            'session',
-            self::CHANNEL_SHELL,
-            $this->window_size_server_to_client[self::CHANNEL_SHELL],
-            $packet_size
-        );
-
-        $this->send_binary_packet($packet);
-
-        $this->channel_status[self::CHANNEL_SHELL] = MessageType::CHANNEL_OPEN;
-
-        $this->get_channel_packet(self::CHANNEL_SHELL);
 
         $terminal_modes = pack('C', TerminalMode::TTY_OP_END);
         $packet = Strings::packSSH2(
@@ -2801,22 +2827,7 @@ class SSH2
      */
     public function startSubsystem(string $subsystem): bool
     {
-        $this->window_size_server_to_client[self::CHANNEL_SUBSYSTEM] = $this->window_size;
+        $this->openChannel(self::CHANNEL_SUBSYSTEM);
-
-        $packet = Strings::packSSH2(
-            'CsN3',
-            MessageType::CHANNEL_OPEN,
-            'session',
-            self::CHANNEL_SUBSYSTEM,
-            $this->window_size,
-            0x4000
-        );
-
-        $this->send_binary_packet($packet);
-
-        $this->channel_status[self::CHANNEL_SUBSYSTEM] = MessageType::CHANNEL_OPEN;
-
-        $this->get_channel_packet(self::CHANNEL_SUBSYSTEM);
 
         $packet = Strings::packSSH2(
             'CNsCs',
@@ -2977,23 +2988,8 @@ class SSH2
             return false;
         }
 
-        $this->window_size_server_to_client[self::CHANNEL_KEEP_ALIVE] = $this->window_size;
-        $packet_size = 0x4000;
-        $packet = Strings::packSSH2(
-            'CsN3',
-            MessageType::CHANNEL_OPEN,
-            'session',
-            self::CHANNEL_KEEP_ALIVE,
-            $this->window_size_server_to_client[self::CHANNEL_KEEP_ALIVE],
-            $packet_size
-        );
-
         try {
-            $this->send_binary_packet($packet);
+            $this->openChannel(self::CHANNEL_KEEP_ALIVE);
-
-            $this->channel_status[self::CHANNEL_KEEP_ALIVE] = MessageType::CHANNEL_OPEN;
-
-            $response = $this->get_channel_packet(self::CHANNEL_KEEP_ALIVE);
         } catch (\RuntimeException $e) {
             return $this->reconnect();
         }