paramiko.auth

38 """ 39 Internal class to handle the mechanics of authentication. 40 """ 41

42 - def __init__(self, transport):

43 self.transport = weakref.proxy(transport) 44 self.username = None 45 self.authenticated = False 46 self.auth_event = None 47 self.auth_method = '' 48 self.password = None 49 self.private_key = None 50 self.interactive_handler = None 51 self.submethods = None 52 # for server mode: 53 self.auth_username = None 54 self.auth_fail_count = 0

55

56 - def is_authenticated(self):

57 return self.authenticated

58

59 - def get_username(self):

60 if self.transport.server_mode: 61 return self.auth_username 62 else: 63 return self.username

64

65 - def auth_none(self, username, event):

66 self.transport.lock.acquire() 67 try: 68 self.auth_event = event 69 self.auth_method = 'none' 70 self.username = username 71 self._request_auth() 72 finally: 73 self.transport.lock.release()

74

75 - def auth_publickey(self, username, key, event):

76 self.transport.lock.acquire() 77 try: 78 self.auth_event = event 79 self.auth_method = 'publickey' 80 self.username = username 81 self.private_key = key 82 self._request_auth() 83 finally: 84 self.transport.lock.release()

85

86 - def auth_password(self, username, password, event):

87 self.transport.lock.acquire() 88 try: 89 self.auth_event = event 90 self.auth_method = 'password' 91 self.username = username 92 self.password = password 93 self._request_auth() 94 finally: 95 self.transport.lock.release()

96

97 - def auth_interactive(self, username, handler, event, submethods=''):

98 """ 99 response_list = handler(title, instructions, prompt_list) 100 """ 101 self.transport.lock.acquire() 102 try: 103 self.auth_event = event 104 self.auth_method = 'keyboard-interactive' 105 self.username = username 106 self.interactive_handler = handler 107 self.submethods = submethods 108 self._request_auth() 109 finally: 110 self.transport.lock.release()

111

112 - def abort(self):

113 if self.auth_event is not None: 114 self.auth_event.set()

115 116 117 ### internals... 118 119

120 - def _request_auth(self):

121 m = Message() 122 m.add_byte(chr(MSG_SERVICE_REQUEST)) 123 m.add_string('ssh-userauth') 124 self.transport._send_message(m)

125

126 - def _disconnect_service_not_available(self):

127 m = Message() 128 m.add_byte(chr(MSG_DISCONNECT)) 129 m.add_int(DISCONNECT_SERVICE_NOT_AVAILABLE) 130 m.add_string('Service not available') 131 m.add_string('en') 132 self.transport._send_message(m) 133 self.transport.close()

134

135 - def _disconnect_no_more_auth(self):

136 m = Message() 137 m.add_byte(chr(MSG_DISCONNECT)) 138 m.add_int(DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE) 139 m.add_string('No more auth methods available') 140 m.add_string('en') 141 self.transport._send_message(m) 142 self.transport.close()

143

144 - def _get_session_blob(self, key, service, username):

145 m = Message() 146 m.add_string(self.transport.session_id) 147 m.add_byte(chr(MSG_USERAUTH_REQUEST)) 148 m.add_string(username) 149 m.add_string(service) 150 m.add_string('publickey') 151 m.add_boolean(1) 152 m.add_string(key.get_name()) 153 m.add_string(str(key)) 154 return str(m)

155

156 - def wait_for_response(self, event):

157 while True: 158 event.wait(0.1) 159 if not self.transport.is_active(): 160 e = self.transport.get_exception() 161 if (e is None) or issubclass(e.__class__, EOFError): 162 e = AuthenticationException('Authentication failed.') 163 raise e 164 if event.isSet(): 165 break 166 if not self.is_authenticated(): 167 e = self.transport.get_exception() 168 if e is None: 169 e = AuthenticationException('Authentication failed.') 170 # this is horrible. python Exception isn't yet descended from 171 # object, so type(e) won't work. :( 172 if issubclass(e.__class__, PartialAuthentication): 173 return e.allowed_types 174 raise e 175 return []

176

177 - def _parse_service_request(self, m):

178 service = m.get_string() 179 if self.transport.server_mode and (service == 'ssh-userauth'): 180 # accepted 181 m = Message() 182 m.add_byte(chr(MSG_SERVICE_ACCEPT)) 183 m.add_string(service) 184 self.transport._send_message(m) 185 return 186 # dunno this one 187 self._disconnect_service_not_available()

188

189 - def _parse_service_accept(self, m):

190 service = m.get_string() 191 if service == 'ssh-userauth': 192 self.transport._log(DEBUG, 'userauth is OK') 193 m = Message() 194 m.add_byte(chr(MSG_USERAUTH_REQUEST)) 195 m.add_string(self.username) 196 m.add_string('ssh-connection') 197 m.add_string(self.auth_method) 198 if self.auth_method == 'password': 199 m.add_boolean(False) 200 password = self.password 201 if isinstance(password, unicode): 202 password = password.encode('UTF-8') 203 m.add_string(password) 204 elif self.auth_method == 'publickey': 205 m.add_boolean(True) 206 m.add_string(self.private_key.get_name()) 207 m.add_string(str(self.private_key)) 208 blob = self._get_session_blob(self.private_key, 'ssh-connection', self.username) 209 sig = self.private_key.sign_ssh_data(self.transport.rng, blob) 210 m.add_string(str(sig)) 211 elif self.auth_method == 'keyboard-interactive': 212 m.add_string('') 213 m.add_string(self.submethods) 214 elif self.auth_method == 'none': 215 pass 216 else: 217 raise SSHException('Unknown auth method "%s"' % self.auth_method) 218 self.transport._send_message(m) 219 else: 220 self.transport._log(DEBUG, 'Service request "%s" accepted (?)' % service)

221

222 - def _send_auth_result(self, username, method, result):

223 # okay, send result 224 m = Message() 225 if result == AUTH_SUCCESSFUL: 226 self.transport._log(INFO, 'Auth granted (%s).' % method) 227 m.add_byte(chr(MSG_USERAUTH_SUCCESS)) 228 self.authenticated = True 229 else: 230 self.transport._log(INFO, 'Auth rejected (%s).' % method) 231 m.add_byte(chr(MSG_USERAUTH_FAILURE)) 232 m.add_string(self.transport.server_object.get_allowed_auths(username)) 233 if result == AUTH_PARTIALLY_SUCCESSFUL: 234 m.add_boolean(1) 235 else: 236 m.add_boolean(0) 237 self.auth_fail_count += 1 238 self.transport._send_message(m) 239 if self.auth_fail_count >= 10: 240 self._disconnect_no_more_auth() 241 if result == AUTH_SUCCESSFUL: 242 self.transport._auth_trigger()

243

244 - def _interactive_query(self, q):

245 # make interactive query instead of response 246 m = Message() 247 m.add_byte(chr(MSG_USERAUTH_INFO_REQUEST)) 248 m.add_string(q.name) 249 m.add_string(q.instructions) 250 m.add_string('') 251 m.add_int(len(q.prompts)) 252 for p in q.prompts: 253 m.add_string(p[0]) 254 m.add_boolean(p[1]) 255 self.transport._send_message(m)

256

257 - def _parse_userauth_request(self, m):

258 if not self.transport.server_mode: 259 # er, uh... what? 260 m = Message() 261 m.add_byte(chr(MSG_USERAUTH_FAILURE)) 262 m.add_string('none') 263 m.add_boolean(0) 264 self.transport._send_message(m) 265 return 266 if self.authenticated: 267 # ignore 268 return 269 username = m.get_string() 270 service = m.get_string() 271 method = m.get_string() 272 self.transport._log(DEBUG, 'Auth request (type=%s) service=%s, username=%s' % (method, service, username)) 273 if service != 'ssh-connection': 274 self._disconnect_service_not_available() 275 return 276 if (self.auth_username is not None) and (self.auth_username != username): 277 self.transport._log(WARNING, 'Auth rejected because the client attempted to change username in mid-flight') 278 self._disconnect_no_more_auth() 279 return 280 self.auth_username = username 281 282 if method == 'none': 283 result = self.transport.server_object.check_auth_none(username) 284 elif method == 'password': 285 changereq = m.get_boolean() 286 password = m.get_string() 287 try: 288 password = password.decode('UTF-8') 289 except UnicodeError: 290 # some clients/servers expect non-utf-8 passwords! 291 # in this case, just return the raw byte string. 292 pass 293 if changereq: 294 # always treated as failure, since we don't support changing passwords, but collect 295 # the list of valid auth types from the callback anyway 296 self.transport._log(DEBUG, 'Auth request to change passwords (rejected)') 297 newpassword = m.get_string() 298 try: 299 newpassword = newpassword.decode('UTF-8', 'replace') 300 except UnicodeError: 301 pass 302 result = AUTH_FAILED 303 else: 304 result = self.transport.server_object.check_auth_password(username, password) 305 elif method == 'publickey': 306 sig_attached = m.get_boolean() 307 keytype = m.get_string() 308 keyblob = m.get_string() 309 try: 310 key = self.transport._key_info[keytype](Message(keyblob)) 311 except SSHException, e: 312 self.transport._log(INFO, 'Auth rejected: public key: %s' % str(e)) 313 key = None 314 except: 315 self.transport._log(INFO, 'Auth rejected: unsupported or mangled public key') 316 key = None 317 if key is None: 318 self._disconnect_no_more_auth() 319 return 320 # first check if this key is okay... if not, we can skip the verify 321 result = self.transport.server_object.check_auth_publickey(username, key) 322 if result != AUTH_FAILED: 323 # key is okay, verify it 324 if not sig_attached: 325 # client wants to know if this key is acceptable, before it 326 # signs anything... send special "ok" message 327 m = Message() 328 m.add_byte(chr(MSG_USERAUTH_PK_OK)) 329 m.add_string(keytype) 330 m.add_string(keyblob) 331 self.transport._send_message(m) 332 return 333 sig = Message(m.get_string()) 334 blob = self._get_session_blob(key, service, username) 335 if not key.verify_ssh_sig(blob, sig): 336 self.transport._log(INFO, 'Auth rejected: invalid signature') 337 result = AUTH_FAILED 338 elif method == 'keyboard-interactive': 339 lang = m.get_string() 340 submethods = m.get_string() 341 result = self.transport.server_object.check_auth_interactive(username, submethods) 342 if isinstance(result, InteractiveQuery): 343 # make interactive query instead of response 344 self._interactive_query(result) 345 return 346 else: 347 result = self.transport.server_object.check_auth_none(username) 348 # okay, send result 349 self._send_auth_result(username, method, result)

350

351 - def _parse_userauth_success(self, m):

352 self.transport._log(INFO, 'Authentication (%s) successful!' % self.auth_method) 353 self.authenticated = True 354 self.transport._auth_trigger() 355 if self.auth_event != None: 356 self.auth_event.set()

357

358 - def _parse_userauth_failure(self, m):

359 authlist = m.get_list() 360 partial = m.get_boolean() 361 if partial: 362 self.transport._log(INFO, 'Authentication continues...') 363 self.transport._log(DEBUG, 'Methods: ' + str(authlist)) 364 self.transport.saved_exception = PartialAuthentication(authlist) 365 elif self.auth_method not in authlist: 366 self.transport._log(DEBUG, 'Authentication type (%s) not permitted.' % self.auth_method) 367 self.transport._log(DEBUG, 'Allowed methods: ' + str(authlist)) 368 self.transport.saved_exception = BadAuthenticationType('Bad authentication type', authlist) 369 else: 370 self.transport._log(INFO, 'Authentication (%s) failed.' % self.auth_method) 371 self.authenticated = False 372 self.username = None 373 if self.auth_event != None: 374 self.auth_event.set()

375

376 - def _parse_userauth_banner(self, m):

377 banner = m.get_string() 378 lang = m.get_string() 379 self.transport._log(INFO, 'Auth banner: ' + banner)

380 # who cares. 381

382 - def _parse_userauth_info_request(self, m):

383 if self.auth_method != 'keyboard-interactive': 384 raise SSHException('Illegal info request from server') 385 title = m.get_string() 386 instructions = m.get_string() 387 m.get_string() # lang 388 prompts = m.get_int() 389 prompt_list = [] 390 for i in range(prompts): 391 prompt_list.append((m.get_string(), m.get_boolean())) 392 response_list = self.interactive_handler(title, instructions, prompt_list) 393 394 m = Message() 395 m.add_byte(chr(MSG_USERAUTH_INFO_RESPONSE)) 396 m.add_int(len(response_list)) 397 for r in response_list: 398 m.add_string(r) 399 self.transport._send_message(m)

400

401 - def _parse_userauth_info_response(self, m):

402 if not self.transport.server_mode: 403 raise SSHException('Illegal info response from server') 404 n = m.get_int() 405 responses = [] 406 for i in range(n): 407 responses.append(m.get_string()) 408 result = self.transport.server_object.check_auth_interactive_response(responses) 409 if isinstance(type(result), InteractiveQuery): 410 # make interactive query instead of response 411 self._interactive_query(result) 412 return 413 self._send_auth_result(self.auth_username, 'keyboard-interactive', result)

414 415 416 _handler_table = { 417 MSG_SERVICE_REQUEST: _parse_service_request, 418 MSG_SERVICE_ACCEPT: _parse_service_accept, 419 MSG_USERAUTH_REQUEST: _parse_userauth_request, 420 MSG_USERAUTH_SUCCESS: _parse_userauth_success, 421 MSG_USERAUTH_FAILURE: _parse_userauth_failure, 422 MSG_USERAUTH_BANNER: _parse_userauth_banner, 423 MSG_USERAUTH_INFO_REQUEST: _parse_userauth_info_request, 424 MSG_USERAUTH_INFO_RESPONSE: _parse_userauth_info_response, 425 }

Source Code for Module paramiko.auth_handler