Due to a lack of complete examples, here's a simple SSH2 class for connecting to a server, authenticating with public key authentication, verifying the server's fingerprint, issuing commands and reading their STDOUT and properly disconnecting. Note: You may need to make sure you commands produce output so the response can be pulled. Some people suggest that the command is not executed until you pull the response back.
<?php
class NiceSSH {
// SSH Host
private $ssh_host = 'myserver.example.com';
// SSH Port
private $ssh_port = 22;
// SSH Server Fingerprint
private $ssh_server_fp = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
// SSH Username
private $ssh_auth_user = 'username';
// SSH Public Key File
private $ssh_auth_pub = '/home/username/.ssh/id_rsa.pub';
// SSH Private Key File
private $ssh_auth_priv = '/home/username/.ssh/id_rsa';
// SSH Private Key Passphrase (null == no passphrase)
private $ssh_auth_pass;
// SSH Connection
private $connection;
public function connect() {
if (!($this->connection = ssh2_connect($this->ssh_host, $this->ssh_port))) {
throw new Exception('Cannot connect to server');
}
$fingerprint = ssh2_fingerprint($this->connection, SSH2_FINGERPRINT_MD5 | SSH2_FINGERPRINT_HEX);
if (strcmp($this->ssh_server_fp, $fingerprint) !== 0) {
throw new Exception('Unable to verify server identity!');
}
if (!ssh2_auth_pubkey_file($this->connection, $this->ssh_auth_user, $this->ssh_auth_pub, $this->ssh_auth_priv, $this->ssh_auth_pass)) {
throw new Exception('Autentication rejected by server');
}
}
public function exec($cmd) {
if (!($stream = ssh2_exec($this->connection, $cmd))) {
throw new Exception('SSH command failed');
}
stream_set_blocking($stream, true);
$data = "";
while ($buf = fread($stream, 4096)) {
$data .= $buf;
}
fclose($stream);
return $data;
}
public function disconnect() {
$this->exec('echo "EXITING" && exit;');
$this->connection = null;
}
public function __destruct() {
$this->disconnect();
}
}
?>
[EDIT BY danbrown AT php DOT net: Contains two bugfixes suggested by 'AlainC' in user note #109185 (removed) on 26-JUN-2012.]
ssh2_connect
(PECL ssh2 >= 0.9.0)
ssh2_connect — Connexion à un serveur SSH
Description
ssh2_connect(
string
int
array
array
): resource|false
string
$host,int
$port = 22,array
$methods = ?,array
$callbacks = ?): resource|false
Établit une connexion à un serveur SSH distant.
Une fois connecté, le client doit vérifier la clé hôte du serveur en utilisant la fonction ssh2_fingerprint(), puis s'identifier en utilisant soit un mot de passe, soit une clé publique.
Liste de paramètres
-
host -
-
port -
-
methods -
methodsdoit être un tableau associatif d'au plus quatre paramètres, comme décrit ci-dessous.methodspeut contenir n'importe quel ou tous les paramètres suivants.Options de connexion SSH Index Signification Valeurs supportées * kex La liste des méthodes d'échange à annoncer, séparées par une virgule, par ordre de préférence. diffie-hellman-group1-sha1,diffie-hellman-group14-sha1, etdiffie-hellman-group-exchange-sha1hostkey La liste des méthodes de clés d'hôte à annoncer, séparées par une virgule, par ordre de préférence. ssh-rsaetssh-dssclient_to_server Tableau associatif contenant les codes des méthodes de chiffrement, de compression et de messages d'identification (MAC) préférés pour l'envoi des messages depuis le client vers le serveur. server_to_client Tableau associatif contenant les codes des méthodes de chiffrement, de compression et de messages d'identification (MAC) préférés pour l'envoi des messages depuis le serveur vers le client. * - Les valeurs supportées sont dépendantes des méthodes supportées par la bibliothèque. Voir la documentation » libssh2 pour plus d'informations.
client_to_serveretserver_to_clientdoivent être un tableau associatif avec n'importe quel ou tous les paramètres suivants.Index Signification Valeurs supportées * crypt Liste des méthodes de chiffrement à annoncer, séparées par une virgule, par ordre de préférence. rijndael-cbc@lysator.liu.se,aes256-cbc,aes192-cbc,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour, etnone**comp Liste des méthodes de compression à annoncer, séparées par une virgule, par ordre de préférence. zlibetnonemac Liste des méthodes MAC à annoncer, séparées par une virgule, par ordre de préférence. hmac-sha1,hmac-sha1-96,hmac-ripemd160,hmac-ripemd160@openssh.com, etnone**Note: Chiffrement et méthode MAC "
none"
Pour des raisons de sécurité,
noneest désactivé par la bibliothèque » libssh2 à moins qu'il soit activé explicitement durant la compilation en utilisant les options appropriées du ./configure. Voir la documentation sur la bibliothèque pour plus d'informations. -
callbacks -
callbackssdoit être un tableau associatif contenant n'importe quel ou tous les paramètres suivants.Paramètres de rappel Index Signification Prototype ignore Nom de la fonction à appeler lorsqu'un paquet SSH2_MSG_IGNOREest reçuvoid ignore_cb($message)debug Nom de la fonction à appeler lorsqu'un paquet SSH2_MSG_DEBUGest reçuvoid debug_cb($message, $language, $always_display)macerror Nom de la fonction à appeler lorsqu'un paquet est reçu mais que le code message d'identification échoue. Si le la fonction de rappel retourne true, l'erreur sera ignorée, sinon, la connexion se terminera.bool macerror_cb($packet)disconnect Nom de la fonction à appeler lorsqu'un paquet SSH2_MSG_DISCONNECTest reçuvoid disconnect_cb($reason, $message, $language)
Valeurs de retour
Retourne une ressource en cas de succès, ou false si une erreur survient.
Exemples
Exemple #1 Exemple avec ssh2_connect()
Ouverture d'une connexion forçant 3des-cbc lors de l'envoi de paquets, n'importe quel chiffrement AES lors de la réception de paquets, aucune compression dans les deux directions, et un échange de clés Group1.
<?php
/* Notification à l'utilisateur si le serveur termine la connexion */
function my_ssh_disconnect($reason, $message, $language) {
printf("Server disconnected with reason code [%d] and message: %s\n",
$reason, $message);
}
$methods = array(
'kex' => 'diffie-hellman-group1-sha1',
'client_to_server' => array(
'crypt' => '3des-cbc',
'comp' => 'none'),
'server_to_client' => array(
'crypt' => 'aes256-cbc,aes192-cbc,aes128-cbc',
'comp' => 'none'));
$callbacks = array('disconnect' => 'my_ssh_disconnect');
$connection = ssh2_connect('shell.example.com', 22, $methods, $callbacks);
if (!$connection) die('Échec de la connexion');
?>Voir aussi
- ssh2_fingerprint() - Récupère l'empreinte d'un serveur distant
- ssh2_auth_none() - Identification en tant que "none"
- ssh2_auth_password() - Identification via SSH en utilisant un mot de passe en clair
- ssh2_auth_pubkey_file() - Identification en utilisant une clé publique
- ssh2_disconnect() - Ferme une connexion à un serveur SSH distant
add a note
User Contributed Notes 8 notes
Steve Kamerman ¶
13 years ago
thessoro at gmail dot com ¶
9 years ago
Be careful when providing a specific hostkey order.
<?php
ssh2_connect('IP', 'port', array('hostkey'=>'ssh-rsa, ssh-dss'));
?>
Will only work when the public key of the server is RSA, and not DSA also as expected. This is caused by the empty space before the "ssh-dss".
So a similar code:
<?php
ssh2_connect('IP', 'port', array('hostkey'=>'ssh-rsa,ssh-dss'));
?>
Will work. The HOSTKEY method is overriden using exactly what you write, so no empty spaces are allowed.
This took me some time that you could save ;)
jrdbrndt at gmail dot com ¶
4 years ago
Trying to include "aes256-cbc" in the encryption methods list caused an error. The documentation here may be out of date, and you might find a more accurate list of what values are acceptable by checking the libssh2 documentation at libssh2.org.
christophermjgray at gmail dot com ¶
7 years ago
This page is out of date. Any of the SHA-1 in the Key Exchange Methods in the kex section should be discarded, due to Logjam (https://weakdh.org/logjam.html). If you continue to use them, connects will result in the following warning:
"Warning: ssh2_connect(): Error starting up SSH connection(-5): Unable to exchange encryption keys in ..."
The following is an example of what works. Also by removing the 'hex' section all together, results in libssl (https://libssh2.org/) falling back to discovering which is the strongest cipher to authenticate with.
<?php
if (!function_exists("ssh2_connect")) die("function ssh2_connect doesn't exist");
function ssh2_debug($message, $language, $always_display) {
printf("%s %s %s\n",$message,$language,$always_display);
}
/* Notify the user if the server terminates the connection */
function my_ssh_disconnect($reason, $message, $language) {
printf("Server disconnected with reason code [%d] and message: %s\n", $reason, $message);
}
$methods = array(
'hostkey'=>'ssh-rsa,ssh-dss',
// 'kex' => 'diffie-hellman-group-exchange-sha256',
'client_to_server' => array(
'crypt' => 'aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,3des-cbc,blowfish-cbc',
'comp' => 'none'),
'server_to_client' => array(
'crypt' => 'aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,3des-cbc,blowfish-cbc',
'comp' => 'none'));
$callbacks = array('disconnect' => 'my_ssh_disconnect');
foreach (array('192.168.1.1') as $host) {
$connection = ssh2_connect($host, 22, $methods, $callbacks);
if (!$connection) die("Connection failed:");
ssh2_auth_password($connection, 'user', 'my_password') or die("Unable to authenticate");
$stream = ssh2_exec($connection, 'free -m');
stream_set_blocking($stream, true);
$stream_out = ssh2_fetch_stream($stream, SSH2_STREAM_STDIO);
echo stream_get_contents($stream_out);
}
?>
Trev White ¶
11 years ago
Hi,
If you are having problems with running a ssh2 session and it waits forever during the execution of stream_get_contents, it might be because the remote system has run the command and is now sitting at a # prompt waiting for the next command. I had this issue on a HP MSA box, here is the code to get around the issue.
Assuming you are connected with your authentication method and $ssh contains the handle.
<?php
$command = "check disk";
// Open a nice large window to stop wrapping
$stream = ssh2_shell ($ssh, 'xterm', null, 200, 200, SSH2_TERM_UNIT_CHARS);
// Hook into the error stream
$errorStream = ssh2_fetch_stream($stream, SSH2_STREAM_STDERR);
// Block the streams so we wait until they complete
stream_set_blocking ($stream, true);
stream_set_blocking($errorStream, true);
// Send the commands to the terminal
fwrite ($stream, $command . PHP_EOL );
// Wait give the terminal a chance to accept and start processing the command, this is a slow storage device after all
sleep(2);
// IMPORTANT BIT!! Send exit to the terminal to close the connection BEFORE WE WAIT FOR THE STREAM
fwrite ($stream, "exit" . PHP_EOL );
sleep (2);
// Print the output
echo stream_get_contents($stream);
$errortext=stream_get_contents($errorStream);
if (strlen($errortext) > 0) {
// Error Data
echo "Error Data: $errortext";
exit (1);
}
// All Good
exit (0);
?>
You can't use ssh2_exec with this method (well at lease I couldn't) because on executing the first command the stream gets blocked and then you can't run the exit command, whereas a terminal seems to use one session.
I hope this helps someone.
suri dot suribala dot com ¶
19 years ago
With Sara's help, I have the following SS2 class that is quite flexible. If anyone improves it, please feel free to let me know.
<?php
// ssh protocols
// note: once openShell method is used, cmdExec does not work
class ssh2 {
private $host = 'host';
private $user = 'user';
private $port = '22';
private $password = 'password';
private $con = null;
private $shell_type = 'xterm';
private $shell = null;
private $log = '';
function __construct($host='', $port='' ) {
if( $host!='' ) $this->host = $host;
if( $port!='' ) $this->port = $port;
$this->con = ssh2_connect($this->host, $this->port);
if( !$this->con ) {
$this->log .= "Connection failed !";
}
}
function authPassword( $user = '', $password = '' ) {
if( $user!='' ) $this->user = $user;
if( $password!='' ) $this->password = $password;
if( !ssh2_auth_password( $this->con, $this->user, $this->password ) ) {
$this->log .= "Authorization failed !";
}
}
function openShell( $shell_type = '' ) {
if ( $shell_type != '' ) $this->shell_type = $shell_type;
$this->shell = ssh2_shell( $this->con, $this->shell_type );
if( !$this->shell ) $this->log .= " Shell connection failed !";
}
function writeShell( $command = '' ) {
fwrite($this->shell, $command."\n");
}
function cmdExec( ) {
$argc = func_num_args();
$argv = func_get_args();
$cmd = '';
for( $i=0; $i<$argc ; $i++) {
if( $i != ($argc-1) ) {
$cmd .= $argv[$i]." && ";
}else{
$cmd .= $argv[$i];
}
}
echo $cmd;
$stream = ssh2_exec( $this->con, $cmd );
stream_set_blocking( $stream, true );
return fread( $stream, 4096 );
}
function getLog() {
return $this->log;
}
}
?>
devoldemar ¶
1 year ago
Usage of 'hostkey' option makes sence when you need to check authenticity of the remote server, e.g. by means of ssh2_fingerprint function. For that purpose you specify a list of possible algorithms sorted by priority in descending order. Supported values also include 'ssh-ed25519', 'ecdsa-sha2-nistp256', 'ecdsa-sha2-nistp384' and 'ecdsa-sha2-nistp521'.
For instance:
<?php
$ssh = ssh2_connect('192.168.3.1', 22, ['hostkey' => 'ssh-ed25519,ssh-rsa']);
$md5 = ssh2_fingerprint($ssh); // returns MD5 hash of ED25519 host key, or MD5 hash of RSA key if the key of previous type is absent
?>
Note, if the remote server does not have a key of appropriate type connection will fail:
<?php
$ssh = ssh2_connect('192.168.3.1', 22, ['hostkey' => 'ssh-dss']);
PHP Warning: ssh2_connect(): Error starting up SSH connection(-5): Unable to exchange encryption keys in php shell code on line 1
PHP Warning: ssh2_connect(): Unable to connect to 192.168.3.1 in php shell code on line 1
?>
rainerkrauss at googlemail dot com ¶
10 years ago
Warning! If you open a ssh connection and execute an external program opening another ssh connection it may result in very strange behavior.
I used an sftp connection to get a file list and used "exec" to download the files afterwards with an external sftp. lftp downloaded zeros with no comment, psftp exits with error code 11 most of the time, but sometimes it works - probably depending on how quickly php collects garbage and closes the unused connection first.
As there is no function to close a connection, you need to be sure to destroy all references (unset) to close it.
