def paramiko_run_test_command(transport, cmd): from paramiko import SSHException log("paramiko_run_test_command(transport, %r)", cmd) try: chan = transport.open_session(window_size=None, max_packet_size=0, timeout=60) chan.set_name("find %s" % cmd) except SSHException as e: log("open_session", exc_info=True) raise InitExit(EXIT_SSH_FAILURE, "failed to open SSH session: %s" % e) from None chan.exec_command(cmd) log("exec_command returned") start = monotonic_time() while not chan.exit_status_ready(): if monotonic_time()-start>TEST_COMMAND_TIMEOUT: chan.close() raise InitException("SSH test command '%s' timed out" % cmd) log("exit status is not ready yet, sleeping") sleep(0.01) code = chan.recv_exit_status() log("exec_command('%s')=%s", cmd, code) def chan_read(read_fn): try: return read_fn() except socket.error: log("chan_read(%s)", read_fn, exc_info=True) return b"" #don't wait too long for the data: chan.settimeout(EXEC_STDOUT_TIMEOUT) out = chan_read(chan.makefile().readline) log("exec_command out=%r", out) chan.settimeout(EXEC_STDERR_TIMEOUT) err = chan_read(chan.makefile_stderr().readline) log("exec_command err=%r", err) chan.close() return out, err, code
def ssh_exec_connect_to(display_desc, opts=None, debug_cb=None, ssh_fail_cb=ssh_connect_failed): if not ssh_fail_cb: ssh_fail_cb = ssh_connect_failed sshpass_command = None try: cmd = list(display_desc["full_ssh"]) kwargs = {} env = display_desc.get("env") kwargs["stderr"] = sys.stderr if WIN32: from subprocess import CREATE_NEW_PROCESS_GROUP, CREATE_NEW_CONSOLE, STARTUPINFO, STARTF_USESHOWWINDOW startupinfo = STARTUPINFO() startupinfo.dwFlags |= STARTF_USESHOWWINDOW startupinfo.wShowWindow = 0 #aka win32.con.SW_HIDE flags = CREATE_NEW_PROCESS_GROUP | CREATE_NEW_CONSOLE kwargs.update({ "startupinfo" : startupinfo, "creationflags" : flags, "stderr" : PIPE, }) elif not display_desc.get("exit_ssh", False) and not OSX: kwargs["start_new_session"] = True remote_xpra = display_desc["remote_xpra"] assert remote_xpra socket_dir = display_desc.get("socket_dir") proxy_command = display_desc["proxy_command"] #ie: "_proxy_start" display_as_args = display_desc["display_as_args"] #ie: "--start=xterm :10" remote_cmd = "" for x in remote_xpra: if not remote_cmd: check = "if" else: check = "elif" if x=="xpra": #no absolute path, so use "which" to check that the command exists: pc = ['%s which "%s" > /dev/null 2>&1; then' % (check, x)] else: pc = ['%s [ -x %s ]; then' % (check, x)] pc += [x] + proxy_command + [shellquote(x) for x in display_as_args] if socket_dir: pc.append("--socket-dir=%s" % socket_dir) remote_cmd += " ".join(pc)+";" remote_cmd += "else echo \"no run-xpra command found\"; exit 1; fi" if INITENV_COMMAND: remote_cmd = INITENV_COMMAND + ";" + remote_cmd #how many times we need to escape the remote command string #depends on how many times the ssh command is parsed nssh = sum(int(x=="ssh") for x in cmd) if nssh>=2 and MAGIC_QUOTES: for _ in range(nssh): remote_cmd = shlex.quote(remote_cmd) else: remote_cmd = "'%s'" % remote_cmd cmd.append("sh -c %s" % remote_cmd) if debug_cb: debug_cb("starting %s tunnel" % str(cmd[0])) #non-string arguments can make Popen choke, #instead of lazily converting everything to a string, we validate the command: for x in cmd: if not isinstance(x, str): raise InitException("argument is not a string: %s (%s), found in command: %s" % (x, type(x), cmd)) password = display_desc.get("password") if password and not display_desc.get("is_putty", False): from xpra.platform.paths import get_sshpass_command sshpass_command = get_sshpass_command() if sshpass_command: #sshpass -e ssh ... cmd.insert(0, sshpass_command) cmd.insert(1, "-e") if env is None: env = os.environ.copy() env["SSHPASS"] = password #the password will be used by ssh via sshpass, #don't try to authenticate again over the ssh-proxy connection, #which would trigger warnings if the server does not require #authentication over unix-domain-sockets: opts.password = None del display_desc["password"] if env: kwargs["env"] = env if is_debug_enabled("ssh"): log.info("executing ssh command: %s" % (" ".join("\"%s\"" % x for x in cmd))) child = Popen(cmd, stdin=PIPE, stdout=PIPE, **kwargs) except OSError as e: raise InitExit(EXIT_SSH_FAILURE, "Error running ssh command '%s': %s" % (" ".join("\"%s\"" % x for x in cmd), e)) def abort_test(action): """ if ssh dies, we don't need to try to read/write from its sockets """ e = child.poll() if e is not None: had_connected = conn.input_bytecount>0 or conn.output_bytecount>0 if had_connected: error_message = "cannot %s using SSH" % action else: error_message = "SSH connection failure" sshpass_error = None if sshpass_command: sshpass_error = { 1 : "Invalid command line argument", 2 : "Conflicting arguments given", 3 : "General runtime error", 4 : "Unrecognized response from ssh (parse error)", 5 : "Invalid/incorrect password", 6 : "Host public key is unknown. sshpass exits without confirming the new key.", }.get(e) if sshpass_error: error_message += ": %s" % sshpass_error if debug_cb: debug_cb(error_message) if ssh_fail_cb: ssh_fail_cb(error_message) if "ssh_abort" not in display_desc: display_desc["ssh_abort"] = True if not had_connected: log.error("Error: SSH connection to the xpra server failed") if sshpass_error: log.error(" %s", sshpass_error) else: log.error(" check your username, hostname, display number, firewall, etc") display_name = display_desc["display_name"] log.error(" for server: %s", display_name) else: log.error("The SSH process has terminated with exit code %s", e) cmd_info = " ".join(display_desc["full_ssh"]) log.error(" the command line used was:") log.error(" %s", cmd_info) raise ConnectionClosedException(error_message) from None def stop_tunnel(): if POSIX: #on posix, the tunnel may be shared with other processes #so don't kill it... which may leave it behind after use. #but at least make sure we close all the pipes: for name,fd in { "stdin" : child.stdin, "stdout" : child.stdout, "stderr" : child.stderr, }.items(): try: if fd: fd.close() except Exception as e: print("error closing ssh tunnel %s: %s" % (name, e)) if not display_desc.get("exit_ssh", False): #leave it running return try: if child.poll() is None: child.terminate() except Exception as e: print("error trying to stop ssh tunnel process: %s" % e) host = display_desc["host"] port = display_desc.get("ssh-port", 22) username = display_desc.get("username") display = display_desc.get("display") info = { "host" : host, "port" : port, } from xpra.net.bytestreams import TwoFileConnection conn = TwoFileConnection(child.stdin, child.stdout, abort_test, target=(host, port), socktype="ssh", close_cb=stop_tunnel, info=info) conn.endpoint = host_target_string("ssh", username, host, port, display) conn.timeout = 0 #taken care of by abort_test conn.process = (child, "ssh", cmd) if kwargs.get("stderr")==PIPE: def stderr_reader(): errs = [] while child.poll() is None: try: v = child.stderr.readline() except OSError: log("stderr_reader()", exc_info=True) break if not v: log("SSH EOF on stderr of %s", cmd) break s = bytestostr(v.rstrip(b"\n\r")) if s: errs.append(s) if errs: log.warn("remote SSH stderr:") for e in errs: log.warn(" %s", e) start_thread(stderr_reader, "ssh-stderr-reader", daemon=True) return conn
def paramiko_run_remote_xpra(transport, xpra_proxy_command=None, remote_xpra=None, socket_dir=None, display_as_args=None): from paramiko import SSHException assert remote_xpra log("will try to run xpra from: %s", remote_xpra) def rtc(cmd): return paramiko_run_test_command(transport, cmd) tried = set() for xpra_cmd in remote_xpra: if xpra_cmd.lower() in ("xpra.exe", "xpra_cmd.exe"): #win32 mode, quick and dirty platform test first: r = rtc("ver") if r[2]!=0: continue #let's find where xpra is installed: r = rtc("FOR /F \"usebackq tokens=3*\" %A IN (`REG QUERY \"HKEY_LOCAL_MACHINE\\Software\\Xpra\" /v InstallPath`) DO (echo %A %B)") #pylint: disable=line-too-long if r[2]==0: #found in registry: lines = r[0].splitlines() installpath = bytestostr(lines[-1]) xpra_cmd = "%s\\%s" % (installpath, xpra_cmd) xpra_cmd = xpra_cmd.replace("\\", "\\\\") log("using '%s'", xpra_cmd) elif xpra_cmd.endswith(".exe"): #assume this path exists pass else: #assume Posix and find that command: r = rtc("which %s" % xpra_cmd) if r[2]!=0: continue if r[0]: #use the actual path returned by 'which': try: xpra_cmd = r[0].decode().rstrip("\n\r") except: pass if xpra_cmd in tried: continue tried.add(xpra_cmd) cmd = '"' + xpra_cmd + '" ' + ' '.join(shellquote(x) for x in xpra_proxy_command) if socket_dir: cmd += " \"--socket-dir=%s\"" % socket_dir if display_as_args: cmd += " " cmd += " ".join(shellquote(x) for x in display_as_args) log("cmd(%s, %s)=%s", xpra_proxy_command, display_as_args, cmd) #see https://github.com/paramiko/paramiko/issues/175 #WINDOW_SIZE = 2097152 log("trying to open SSH session, window-size=%i, timeout=%i", WINDOW_SIZE, TIMEOUT) try: chan = transport.open_session(window_size=WINDOW_SIZE, max_packet_size=0, timeout=TIMEOUT) chan.set_name("run-xpra") except SSHException as e: log("open_session", exc_info=True) raise InitExit(EXIT_SSH_FAILURE, "failed to open SSH session: %s" % e) from None else: log("channel exec_command(%s)" % cmd) chan.exec_command(cmd) return chan raise Exception("all SSH remote proxy commands have failed")
def do_ssh_paramiko_connect_to(transport, host, username, password, host_config=None, keyfiles=None, paramiko_config=None): from paramiko import SSHException, PasswordRequiredException from paramiko.agent import Agent from paramiko.hostkeys import HostKeys log("do_ssh_paramiko_connect_to%s", (transport, host, username, password, host_config, keyfiles, paramiko_config)) log("SSH transport %s", transport) def configvalue(key): #if the paramiko config has a setting, honour it: if paramiko_config and key in paramiko_config: return paramiko_config.get(key) #fallback to the value from the host config: return (host_config or {}).get(key) def configbool(key, default_value=True): return parse_bool(key, configvalue(key), default_value) def configint(key, default_value=0): v = configvalue(key) if v is None: return default_value return int(v) host_key = transport.get_remote_server_key() assert host_key, "no remote server key" log("remote_server_key=%s", keymd5(host_key)) if configbool("verify-hostkey", VERIFY_HOSTKEY): host_keys = HostKeys() host_keys_filename = None KNOWN_HOSTS = get_ssh_known_hosts_files() for known_hosts in KNOWN_HOSTS: host_keys.clear() try: path = os.path.expanduser(known_hosts) if os.path.exists(path): host_keys.load(path) log("HostKeys.load(%s) successful", path) host_keys_filename = path break except IOError: log("HostKeys.load(%s)", known_hosts, exc_info=True) log("host keys=%s", host_keys) keys = host_keys.lookup(host) known_host_key = (keys or {}).get(host_key.get_name()) def keyname(): return host_key.get_name().replace("ssh-", "") if host_key==known_host_key: assert host_key log("%s host key '%s' OK for host '%s'", keyname(), keymd5(host_key), host) else: dnscheck = "" if configbool("verifyhostkeydns"): try: from xpra.net.sshfp import check_host_key dnscheck = check_host_key(host, host_key) except ImportError as e: log("verifyhostkeydns failed", exc_info=True) log.warn("Warning: cannot check SSHFP DNS records") log.warn(" %s", e) log("dnscheck=%s", dnscheck) def adddnscheckinfo(q): if dnscheck is not True: if dnscheck: q += [ "SSHFP validation failed:", dnscheck ] else: q += [ "SSHFP validation failed" ] if dnscheck is True: #DNSSEC provided a matching record log.info("found a valid SSHFP record for host %s", host) elif known_host_key: log.warn("Warning: SSH server key mismatch") qinfo = [ "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!", "IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!", "Someone could be eavesdropping on you right now (man-in-the-middle attack)!", "It is also possible that a host key has just been changed.", "The fingerprint for the %s key sent by the remote host is" % keyname(), keymd5(host_key), ] adddnscheckinfo(qinfo) if configbool("stricthostkeychecking", VERIFY_STRICT): log.warn("Host key verification failed.") #TODO: show alert with no option to accept key qinfo += [ "Please contact your system administrator.", "Add correct host key in %s to get rid of this message.", "Offending %s key in %s" % (keyname(), host_keys_filename), "ECDSA host key for %s has changed and you have requested strict checking." % keyname(), ] sys.stderr.write(os.linesep.join(qinfo)) transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") else: assert (not keys) or (host_key.get_name() not in keys) if not keys: log.warn("Warning: unknown SSH host") else: log.warn("Warning: unknown %s SSH host key", keyname()) qinfo = [ "The authenticity of host '%s' can't be established." % (host,), "%s key fingerprint is" % keyname(), keymd5(host_key), ] adddnscheckinfo(qinfo) if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "Unknown SSH host '%s'" % host) if configbool("addkey", ADD_KEY): try: if not host_keys_filename: #the first one is the default, #ie: ~/.ssh/known_hosts on posix host_keys_filename = os.path.expanduser(KNOWN_HOSTS[0]) log("adding %s key for host '%s' to '%s'", keyname(), host, host_keys_filename) if not os.path.exists(host_keys_filename): keys_dir = os.path.dirname(host_keys_filename) if not os.path.exists(keys_dir): log("creating keys directory '%s'", keys_dir) os.mkdir(keys_dir, 0o700) elif not os.path.isdir(keys_dir): log.warn("Warning: '%s' is not a directory") log.warn(" key not saved") if os.path.exists(keys_dir) and os.path.isdir(keys_dir): log("creating known host file '%s'", host_keys_filename) with umask_context(0o133): with open(host_keys_filename, 'a+'): pass host_keys.add(host, host_key.get_name(), host_key) host_keys.save(host_keys_filename) except OSError as e: log("failed to add key to '%s'", host_keys_filename) log.error("Error adding key to '%s'", host_keys_filename) log.error(" %s", e) except Exception as e: log.error("cannot add key", exc_info=True) else: log("ssh host key verification skipped") def auth_agent(): agent = Agent() agent_keys = agent.get_keys() log("agent keys: %s", agent_keys) if agent_keys: for agent_key in agent_keys: log("trying ssh-agent key '%s'", keymd5(agent_key)) try: transport.auth_publickey(username, agent_key) if transport.is_authenticated(): log("authenticated using agent and key '%s'", keymd5(agent_key)) break except SSHException: log("agent key '%s' rejected", keymd5(agent_key), exc_info=True) if not transport.is_authenticated(): log.info("agent authentication failed, tried %i key%s", len(agent_keys), engs(agent_keys)) def auth_publickey(): log("trying public key authentication using %s", keyfiles) for keyfile_path in keyfiles: if not os.path.exists(keyfile_path): log("no keyfile at '%s'", keyfile_path) continue log("trying '%s'", keyfile_path) key = None import paramiko for pkey_classname in ("RSA", "DSS", "ECDSA", "Ed25519"): pkey_class = getattr(paramiko, "%sKey" % pkey_classname, None) if pkey_class is None: log("no %s key type", pkey_classname) continue log("trying to load as %s", pkey_classname) try: key = pkey_class.from_private_key_file(keyfile_path) log.info("loaded %s private key from '%s'", pkey_classname, keyfile_path) break except PasswordRequiredException as e: log("%s keyfile requires a passphrase; %s", keyfile_path, e) passphrase = input_pass("please enter the passphrase for %s:" % (keyfile_path,)) if passphrase: try: key = pkey_class.from_private_key_file(keyfile_path, passphrase) log.info("loaded %s private key from '%s'", pkey_classname, keyfile_path) except SSHException as e: log("from_private_key_file", exc_info=True) log.info("cannot load key from file '%s':", keyfile_path) log.info(" %s", e) break except Exception as e: log("auth_publickey() loading as %s", pkey_classname, exc_info=True) key_data = load_binary_file(keyfile_path) if key_data and key_data.find(b"BEGIN OPENSSH PRIVATE KEY")>=0 and paramiko.__version__<"2.7": log.warn("Warning: private key '%s'", keyfile_path) log.warn(" this file seems to be using OpenSSH's own format") log.warn(" please convert it to something more standard (ie: PEM)") log.warn(" so it can be used with the paramiko backend") log.warn(" or switch to the OpenSSH backend with '--ssh=ssh'") if key: log("auth_publickey using %s as %s: %s", keyfile_path, pkey_classname, keymd5(key)) try: transport.auth_publickey(username, key) except SSHException as e: log("key '%s' rejected", keyfile_path, exc_info=True) log.info("SSH authentication using key '%s' failed:", keyfile_path) log.info(" %s", e) else: if transport.is_authenticated(): break else: log.error("Error: cannot load private key '%s'", keyfile_path) def auth_none(): log("trying none authentication") try: transport.auth_none(username) except SSHException: log("auth_none()", exc_info=True) def auth_password(): log("trying password authentication") try: transport.auth_password(username, password) except SSHException as e: log("auth_password(..)", exc_info=True) log.info("SSH password authentication failed:") log.info(" %s", getattr(e, "message", e)) def auth_interactive(): log("trying interactive authentication") class iauthhandler: def __init__(self): self.authcount = 0 def handlestuff(self, _title, _instructions, prompt_list): p = [] for pent in prompt_list: if self.authcount==0 and password: p.append(password) else: p.append(input_pass(pent[0])) self.authcount += 1 return p try: myiauthhandler = iauthhandler() transport.auth_interactive(username, myiauthhandler.handlestuff, "") except SSHException as e: log("auth_interactive(..)", exc_info=True) log.info("SSH password authentication failed:") log.info(" %s", getattr(e, "message", e)) banner = transport.get_banner() if banner: log.info("SSH server banner:") for x in banner.splitlines(): log.info(" %s", x) if paramiko_config and "auth" in paramiko_config: auth = paramiko_config.get("auth", "").split("+") AUTH_OPTIONS = ("none", "agent", "key", "password") if any(a for a in auth if a not in AUTH_OPTIONS): raise InitExit(EXIT_SSH_FAILURE, "invalid ssh authentication module specified: %s" % csv(a for a in auth if a not in AUTH_OPTIONS)) else: auth = [] if configbool("noneauthentication", NONE_AUTH): auth.append("none") if password and configbool("passwordauthentication", PASSWORD_AUTH): auth.append("password") if configbool("agentauthentication", AGENT_AUTH): auth.append("agent") # Some people do two-factor using KEY_AUTH to kick things off, so this happens first if configbool("keyauthentication", KEY_AUTH): auth.append("key") if not password and configbool("passwordauthentication", PASSWORD_AUTH): auth.append("password") #def doauth(authtype): # return authtype in auth and not transport.is_authenticated() log("starting authentication, authentication methods: %s", auth) # per the RFC we probably should do none first always and read off the supported # methods, however, the current code seems to work fine with OpenSSH while not transport.is_authenticated() and auth: a = auth.pop(0) log("auth=%s", a) if a=="none": auth_none() elif a=="agent": auth_agent() elif a=="key": auth_publickey() elif a=="password": auth_interactive() if not transport.is_authenticated(): if password: auth_password() else: tries = configint("numberofpasswordprompts", PASSWORD_RETRY) for _ in range(tries): password = input_pass("please enter the SSH password for %s@%s:" % (username, host)) if not password: break auth_password() if transport.is_authenticated(): break if not transport.is_authenticated(): transport.close() raise InitExit(EXIT_CONNECTION_FAILED, "SSH Authentication on %s failed" % host)
def ssh_paramiko_connect_to(display_desc): #plain socket attributes: dtype = display_desc["type"] host = display_desc["host"] port = display_desc.get("ssh-port", 22) #ssh and command attributes: username = display_desc.get("username") or get_username() if "proxy_host" in display_desc: display_desc.setdefault("proxy_username", get_username()) password = display_desc.get("password") remote_xpra = display_desc["remote_xpra"] proxy_command = display_desc["proxy_command"] #ie: "_proxy_start" socket_dir = display_desc.get("socket_dir") display = display_desc.get("display") display_as_args = display_desc["display_as_args"] #ie: "--start=xterm :10" paramiko_config = display_desc.copy() paramiko_config.update(display_desc.get("paramiko-config", {})) socket_info = { "host" : host, "port" : port, } def get_keyfiles(host_config, config_name="key"): keyfiles = (host_config or {}).get("identityfile") or get_default_keyfiles() keyfile = paramiko_config.get(config_name) if keyfile: keyfiles.insert(0, keyfile) return keyfiles with nogssapi_context(): from paramiko import SSHConfig, ProxyCommand ssh_config = SSHConfig() user_config_file = os.path.expanduser("~/.ssh/config") sock = None host_config = None if os.path.exists(user_config_file): with open(user_config_file) as f: ssh_config.parse(f) log("parsed user config '%s': %i hosts found", user_config_file, len(ssh_config.get_hostnames())) host_config = ssh_config.lookup(host) if host_config: log("got host config for '%s': %s", host, host_config) chost = host_config.get("hostname", host) cusername = host_config.get("user", username) cport = host_config.get("port", port) try: port = int(cport) except (TypeError, ValueError): raise InitExit(EXIT_SSH_FAILURE, "invalid ssh port specified: '%s'" % cport) from None proxycommand = host_config.get("proxycommand") if proxycommand: log("found proxycommand='%s' for host '%s'", proxycommand, chost) sock = ProxyCommand(proxycommand) log("ProxyCommand(%s)=%s", proxycommand, sock) from xpra.child_reaper import getChildReaper cmd = getattr(sock, "cmd", []) def proxycommand_ended(proc): log("proxycommand_ended(%s) exit code=%s", proc, proc.poll()) getChildReaper().add_process(sock.process, "paramiko-ssh-client", cmd, True, True, callback=proxycommand_ended) proxy_keys = get_keyfiles(host_config, "proxy_key") log("proxy keys=%s", proxy_keys) from paramiko.client import SSHClient ssh_client = SSHClient() ssh_client.load_system_host_keys() log("ssh proxy command connect to %s", (chost, cport, sock)) ssh_client.connect(chost, cport, sock=sock) transport = ssh_client.get_transport() do_ssh_paramiko_connect_to(transport, chost, cusername, password, host_config or ssh_config.lookup("*"), proxy_keys, paramiko_config) chan = paramiko_run_remote_xpra(transport, proxy_command, remote_xpra, socket_dir, display_as_args) peername = (chost, cport) conn = SSHProxyCommandConnection(chan, peername, peername, socket_info) conn.target = host_target_string("ssh", cusername, chost, port, display) conn.timeout = SOCKET_TIMEOUT conn.start_stderr_reader() conn.process = (sock.process, "ssh", cmd) from xpra.net import bytestreams from paramiko.ssh_exception import ProxyCommandFailure bytestreams.CLOSED_EXCEPTIONS = tuple(list(bytestreams.CLOSED_EXCEPTIONS)+[ProxyCommandFailure]) return conn keys = get_keyfiles(host_config) from xpra.scripts.main import socket_connect from paramiko.transport import Transport from paramiko import SSHException if "proxy_host" in display_desc: proxy_host = display_desc["proxy_host"] proxy_port = display_desc.get("proxy_port", 22) proxy_username = display_desc.get("proxy_username", username) proxy_password = display_desc.get("proxy_password", password) proxy_keys = get_keyfiles(host_config, "proxy_key") sock = socket_connect(dtype, proxy_host, proxy_port) middle_transport = Transport(sock) middle_transport.use_compression(False) try: middle_transport.start_client() except SSHException as e: log("start_client()", exc_info=True) raise InitExit(EXIT_SSH_FAILURE, "SSH negotiation failed: %s" % e) from None proxy_host_config = ssh_config.lookup(host) do_ssh_paramiko_connect_to(middle_transport, proxy_host, proxy_username, proxy_password, proxy_host_config or ssh_config.lookup("*"), proxy_keys, paramiko_config) log("Opening proxy channel") chan_to_middle = middle_transport.open_channel("direct-tcpip", (host, port), ('localhost', 0)) transport = Transport(chan_to_middle) transport.use_compression(False) try: transport.start_client() except SSHException as e: log("start_client()", exc_info=True) raise InitExit(EXIT_SSH_FAILURE, "SSH negotiation failed: %s" % e) do_ssh_paramiko_connect_to(transport, host, username, password, host_config or ssh_config.lookup("*"), keys, paramiko_config) chan = paramiko_run_remote_xpra(transport, proxy_command, remote_xpra, socket_dir, display_as_args) peername = (host, port) conn = SSHProxyCommandConnection(chan, peername, peername, socket_info) conn.target = "%s via %s" % ( host_target_string("ssh", username, host, port, display), host_target_string("ssh", proxy_username, proxy_host, proxy_port, None), ) conn.timeout = SOCKET_TIMEOUT conn.start_stderr_reader() return conn #plain TCP connection to the server, #we open it then give the socket to paramiko: sock = socket_connect(dtype, host, port) sockname = sock.getsockname() peername = sock.getpeername() log("paramiko socket_connect: sockname=%s, peername=%s", sockname, peername) transport = Transport(sock) transport.use_compression(False) try: transport.start_client() except SSHException as e: log("start_client()", exc_info=True) raise InitExit(EXIT_SSH_FAILURE, "SSH negotiation failed: %s" % e) from None do_ssh_paramiko_connect_to(transport, host, username, password, host_config or ssh_config.lookup("*"), keys, paramiko_config) chan = paramiko_run_remote_xpra(transport, proxy_command, remote_xpra, socket_dir, display_as_args) conn = SSHSocketConnection(chan, sock, sockname, peername, (host, port), socket_info) conn.target = host_target_string("ssh", username, host, port, display) conn.timeout = SOCKET_TIMEOUT conn.start_stderr_reader() return conn
def do_ssh_paramiko_connect_to(transport, host, username, password, host_config=None): from paramiko import SSHException, RSAKey, PasswordRequiredException from paramiko.agent import Agent from paramiko.hostkeys import HostKeys log("do_ssh_paramiko_connect_to%s", (transport, host, username, password, host_config)) log("SSH transport %s", transport) host_key = transport.get_remote_server_key() assert host_key, "no remote server key" log("remote_server_key=%s", keymd5(host_key)) if VERIFY_HOSTKEY: host_keys = HostKeys() host_keys_filename = None KNOWN_HOSTS = get_ssh_known_hosts_files() for known_hosts in KNOWN_HOSTS: host_keys.clear() try: path = os.path.expanduser(known_hosts) if os.path.exists(path): host_keys.load(path) log("HostKeys.load(%s) successful", path) host_keys_filename = path break except IOError: log("HostKeys.load(%s)", known_hosts, exc_info=True) log("host keys=%s", host_keys) keys = host_keys.lookup(host) known_host_key = (keys or {}).get(host_key.get_name()) def keyname(): return host_key.get_name().replace("ssh-", "") if host_key == known_host_key: assert host_key log("%s host key '%s' OK for host '%s'", keyname(), keymd5(host_key), host) else: dnscheck = "" if host_config: verifyhostkeydns = host_config.get("verifyhostkeydns") if verifyhostkeydns and verifyhostkeydns.lower( ) in TRUE_OPTIONS: try: from xpra.net.sshfp import check_host_key dnscheck = check_host_key(host, host_key) except ImportError as e: log("verifyhostkeydns failed", exc_info=True) log.warn("Warning: cannot check SSHFP DNS records") log.warn(" %s", e) log.info("dnscheck=%s", dnscheck) def adddnscheckinfo(q): if dnscheck is not True: q += ["SSHFP validation failed:", dnscheck] if dnscheck is True: #DNSSEC provided a matching record log.info("found a valid SSHFP record for host %s", host) elif known_host_key: log.warn("Warning: SSH server key mismatch") qinfo = [ "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!", "IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!", "Someone could be eavesdropping on you right now (man-in-the-middle attack)!", "It is also possible that a host key has just been changed.", "The fingerprint for the %s key sent by the remote host is" % keyname(), keymd5(host_key), ] adddnscheckinfo(qinfo) if VERIFY_STRICT: log.warn("Host key verification failed.") #TODO: show alert with no option to accept key qinfo += [ "Please contact your system administrator.", "Add correct host key in %s to get rid of this message.", "Offending %s key in %s" % (keyname(), host_keys_filename), "ECDSA host key for %s has changed and you have requested strict checking." % keyname(), ] sys.stderr.write(os.linesep.join(qinfo)) transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") else: assert (not keys) or (host_key.get_name() not in keys) if not keys: log.warn("Warning: unknown SSH host") else: log.warn("Warning: unknown %s SSH host key", keyname()) qinfo = [ "The authenticity of host '%s' can't be established." % (host, ), "%s key fingerprint is" % keyname(), keymd5(host_key), ] adddnscheckinfo(qinfo) if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "Unknown SSH host '%s'" % host) if ADD_KEY: try: if not host_keys_filename: #the first one is the default, #ie: ~/.ssh/known_hosts on posix host_keys_filename = os.path.expanduser(KNOWN_HOSTS[0]) log("adding %s key for host '%s' to '%s'", keyname(), host, host_keys_filename) if not os.path.exists(host_keys_filename): keys_dir = os.path.dirname(host_keys_filename) if not os.path.exists(keys_dir): log("creating keys directory '%s'", keys_dir) os.mkdir(keys_dir, 0o700) elif not os.path.isdir(keys_dir): log.warn("Warning: '%s' is not a directory") log.warn(" key not saved") if os.path.exists(keys_dir) and os.path.isdir( keys_dir): log("creating known host file '%s'", host_keys_filename) with umask_context(0o133): with open(host_keys_filename, 'a+'): pass host_keys.add(host, host_key.get_name(), host_key) host_keys.save(host_keys_filename) except OSError as e: log("failed to add key to '%s'", host_keys_filename) log.error("Error adding key to '%s'", host_keys_filename) log.error(" %s", e) except Exception as e: log.error("cannot add key", exc_info=True) def auth_agent(): agent = Agent() agent_keys = agent.get_keys() log("agent keys: %s", agent_keys) if agent_keys: for agent_key in agent_keys: log("trying ssh-agent key '%s'", keymd5(agent_key)) try: transport.auth_publickey(username, agent_key) if transport.is_authenticated(): log("authenticated using agent and key '%s'", keymd5(agent_key)) break except SSHException: log("agent key '%s' rejected", keymd5(agent_key), exc_info=True) if not transport.is_authenticated(): log.info("agent authentication failed, tried %i key%s", len(agent_keys), engs(agent_keys)) def auth_publickey(): log("trying public key authentication") for keyfile in ("id_rsa", "id_dsa"): keyfile_path = osexpand(os.path.join("~/", ".ssh", keyfile)) if not os.path.exists(keyfile_path): log("no keyfile at '%s'", keyfile_path) continue key = None try: key = RSAKey.from_private_key_file(keyfile_path) except PasswordRequiredException: log("%s keyfile requires a passphrase", keyfile_path) passphrase = input_pass("please enter the passphrase for %s:" % (keyfile_path, )) if passphrase: try: key = RSAKey.from_private_key_file( keyfile_path, passphrase) except SSHException as e: log("from_private_key_file", exc_info=True) log.info("cannot load key from file '%s':", keyfile_path) log.info(" %s", e) if key: log("auth_publickey using %s: %s", keyfile_path, keymd5(key)) try: transport.auth_publickey(username, key) except SSHException as e: log("key '%s' rejected", keyfile_path, exc_info=True) log.info("SSH authentication using key '%s' failed:", keyfile_path) log.info(" %s", e) else: if transport.is_authenticated(): break def auth_none(): log("trying none authentication") try: transport.auth_none(username) except SSHException as e: log("auth_none()", exc_info=True) def auth_password(): log("trying password authentication") try: transport.auth_password(username, password) except SSHException as e: log("auth_password(..)", exc_info=True) log.info("SSH password authentication failed: %s", e) def auth_interactive(): log("trying interactive authentication") class iauthhandler: def __init__(self): self.authcount = 0 def handlestuff(self, title, instructions, prompt_list): p = [] for pent in prompt_list: if self.authcount == 0 and password: p.append(password) else: p.append(input_pass(pent[0])) self.authcount += 1 return p try: myiauthhandler = iauthhandler() transport.auth_interactive(username, myiauthhandler.handlestuff, "") except SSHException as e: log("auth_interactive(..)", exc_info=True) log.info("SSH password authentication failed: %s", e) banner = transport.get_banner() if banner: log.info("SSH server banner:") for x in banner.splitlines(): log.info(" %s", x) log("starting authentication") # per the RFC we probably should do none first always and read off the supported # methods, however, the current code seems to work fine with OpenSSH if not transport.is_authenticated() and NONE_AUTH: auth_none() # Some people do two-factor using KEY_AUTH to kick things off, so this happens first if not transport.is_authenticated() and KEY_AUTH: auth_publickey() if not transport.is_authenticated() and PASSWORD_AUTH: auth_interactive() if not transport.is_authenticated() and PASSWORD_AUTH and password: auth_password() if not transport.is_authenticated() and AGENT_AUTH: auth_agent() if not transport.is_authenticated() and PASSWORD_AUTH and not password: for _ in range(1 + PASSWORD_RETRY): password = input_pass("please enter the SSH password for %s@%s" % (username, host)) if not password: break auth_password() if transport.is_authenticated(): break if not transport.is_authenticated(): transport.close() raise InitException("SSH Authentication on %s failed" % host)
def fail(msg): log("ssh_paramiko_connect_to(%s)", display_desc, exc_info=True) raise InitExit(EXIT_SSH_FAILURE, msg) from None
def do_ssh_paramiko_connect_to(sock, host, port, username, password, proxy_command, remote_xpra, socket_dir, display_as_args, target): from paramiko import SSHException, Transport, Agent, RSAKey, PasswordRequiredException from paramiko.hostkeys import HostKeys transport = Transport(sock) transport.use_compression(False) log("SSH transport %s", transport) try: transport.start_client() except SSHException as e: log("start_client()", exc_info=True) raise InitException("SSH negotiation failed: %s" % e) host_key = transport.get_remote_server_key() assert host_key, "no remote server key" log("remote_server_key=%s", keymd5(host_key)) if VERIFY_HOSTKEY: host_keys = HostKeys() host_keys_filename = None KNOWN_HOSTS = get_ssh_known_hosts_files() for known_hosts in KNOWN_HOSTS: host_keys.clear() try: path = os.path.expanduser(known_hosts) if os.path.exists(path): host_keys.load(path) log("HostKeys.load(%s) successful", path) host_keys_filename = path break except IOError: log("HostKeys.load(%s)", known_hosts, exc_info=True) log("host keys=%s", host_keys) keys = host_keys.lookup(host) known_host_key = (keys or {}).get(host_key.get_name()) def keyname(): return host_key.get_name().replace("ssh-", "") if host_key==known_host_key: assert host_key log("%s host key '%s' OK for host '%s'", keyname(), keymd5(host_key), host) else: if known_host_key: log.warn("Warning: SSH server key mismatch") qinfo = [ "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!", "IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!", "Someone could be eavesdropping on you right now (man-in-the-middle attack)!", "It is also possible that a host key has just been changed.", "The fingerprint for the %s key sent by the remote host is" % keyname(), keymd5(host_key), ] if VERIFY_STRICT: log.warn("Host key verification failed.") #TODO: show alert with no option to accept key qinfo += [ "Please contact your system administrator.", "Add correct host key in %s to get rid of this message.", "Offending %s key in %s" % (keyname(), host_keys_filename), "ECDSA host key for %s has changed and you have requested strict checking." % keyname(), ] sys.stderr.write(os.linesep.join(qinfo)) transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "SSH Host key has changed") else: assert (not keys) or (host_key.get_name() not in keys) if not keys: log.warn("Warning: unknown SSH host") else: log.warn("Warning: unknown %s SSH host key", keyname()) qinfo = [ "The authenticity of host '%s' can't be established." % (host,), "%s key fingerprint is" % keyname(), keymd5(host_key), ] if not confirm_key(qinfo): transport.close() raise InitExit(EXIT_SSH_KEY_FAILURE, "Unknown SSH host '%s'" % host) if ADD_KEY: try: if not host_keys_filename: #the first one is the default, #ie: ~/.ssh/known_hosts on posix host_keys_filename = os.path.expanduser(KNOWN_HOSTS[0]) log("adding %s key for host '%s' to '%s'", keyname(), host, host_keys_filename) if not os.path.exists(host_keys_filename): keys_dir = os.path.dirname(host_keys_filename) if not os.path.exists(keys_dir): log("creating keys directory '%s'", keys_dir) os.mkdir(keys_dir, 0o700) elif not os.path.isdir(keys_dir): log.warn("Warning: '%s' is not a directory") log.warn(" key not saved") if os.path.exists(keys_dir) and os.path.isdir(keys_dir): log("creating known host file '%s'", host_keys_filename) with umask_context(0o133): with open(host_keys_filename, 'a+'): pass host_keys.add(host, host_key.get_name(), host_key) host_keys.save(host_keys_filename) except OSError as e: log("failed to add key to '%s'", host_keys_filename) log.error("Error adding key to '%s'", host_keys_filename) log.error(" %s", e) except Exception as e: log.error("cannot add key", exc_info=True) def auth_agent(): agent = Agent() agent_keys = agent.get_keys() log("agent keys: %s", agent_keys) if agent_keys: for agent_key in agent_keys: log("trying ssh-agent key '%s'", keymd5(agent_key)) try: transport.auth_publickey(username, agent_key) if transport.is_authenticated(): log("authenticated using agent and key '%s'", keymd5(agent_key)) break except SSHException: log("agent key '%s' rejected", keymd5(agent_key), exc_info=True) if not transport.is_authenticated(): log.info("agent authentication failed, tried %i key%s", len(agent_keys), engs(agent_keys)) def auth_publickey(): log("trying public key authentication") for keyfile in ("id_rsa", "id_dsa"): keyfile_path = osexpand(os.path.join("~/", ".ssh", keyfile)) if not os.path.exists(keyfile_path): log("no keyfile at '%s'", keyfile_path) continue key = None try: key = RSAKey.from_private_key_file(keyfile_path) except PasswordRequiredException: log("%s keyfile requires a passphrase", keyfile_path) passphrase = input_pass("please enter the passphrase for %s:" % (keyfile_path,)) if passphrase: try: key = RSAKey.from_private_key_file(keyfile_path, passphrase) except SSHException as e: log("from_private_key_file", exc_info=True) log.info("cannot load key from file '%s':", keyfile_path) log.info(" %s", e) if key: log("auth_publickey using %s: %s", keyfile_path, keymd5(key)) try: transport.auth_publickey(username, key) except SSHException as e: log("key '%s' rejected", keyfile_path, exc_info=True) log.info("SSH authentication using key '%s' failed:", keyfile_path) log.info(" %s", e) else: if transport.is_authenticated(): break def auth_none(): log("trying none authentication") try: transport.auth_none(username) except SSHException as e: log("auth_none()", exc_info=True) def auth_password(): log("trying password authentication") try: transport.auth_password(username, password) except SSHException as e: log("auth_password(..)", exc_info=True) log.info("SSH password authentication failed: %s", e) banner = transport.get_banner() if banner: log.info("SSH server banner:") for x in banner.splitlines(): log.info(" %s", x) log("starting authentication") if not transport.is_authenticated() and NONE_AUTH: auth_none() if not transport.is_authenticated() and PASSWORD_AUTH and password: auth_password() if not transport.is_authenticated() and AGENT_AUTH: auth_agent() if not transport.is_authenticated() and KEY_AUTH: auth_publickey() if not transport.is_authenticated() and PASSWORD_AUTH and not password: for _ in range(1+PASSWORD_RETRY): password = input_pass("please enter the SSH password for %s@%s" % (username, host)) if not password: break auth_password() if transport.is_authenticated(): break if not transport.is_authenticated(): transport.close() raise InitException("SSH Authentication failed") assert len(remote_xpra)>0 log("will try to run xpra from: %s", remote_xpra) for xpra_cmd in remote_xpra: try: chan = transport.open_session(window_size=None, max_packet_size=0, timeout=60) chan.set_name("find %s" % xpra_cmd) except SSHException as e: log("open_session", exc_info=True) raise InitException("failed to open SSH session: %s" % e) cmd = "which %s" % xpra_cmd log("exec_command('%s')", cmd) chan.exec_command(cmd) #poll until the command terminates: start = monotonic_time() while not chan.exit_status_ready(): if monotonic_time()-start>10: chan.close() raise InitException("SSH test command '%s' timed out" % cmd) log("exit status is not ready yet, sleeping") time.sleep(0.01) r = chan.recv_exit_status() log("exec_command('%s')=%s", cmd, r) chan.close() if r!=0: continue cmd = xpra_cmd + " " + " ".join(shellquote(x) for x in proxy_command) if socket_dir: cmd += " \"--socket-dir=%s\"" % socket_dir if display_as_args: cmd += " " cmd += " ".join(shellquote(x) for x in display_as_args) log("cmd(%s, %s)=%s", proxy_command, display_as_args, cmd) #see https://github.com/paramiko/paramiko/issues/175 #WINDOW_SIZE = 2097152 log("trying to open SSH session, window-size=%i, timeout=%i", WINDOW_SIZE, TIMEOUT) try: chan = transport.open_session(window_size=WINDOW_SIZE, max_packet_size=0, timeout=TIMEOUT) chan.set_name("run-xpra") except SSHException as e: log("open_session", exc_info=True) raise InitException("failed to open SSH session: %s" % e) else: log("channel exec_command(%s)" % cmd) chan.exec_command(cmd) info = { "host" : host, "port" : port, } conn = SSHSocketConnection(chan, sock, target, info) conn.timeout = SOCKET_TIMEOUT conn.start_stderr_reader() child = None conn.process = (child, "ssh", cmd) return conn raise Exception("all SSH remote proxy commands have failed")