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 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)