__init__.py 56.8 KB
Newer Older
Max Beckett's avatar
Max Beckett committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
#!/usr/bin/env python
#
# Copyright 2017-2018 Amazon.com, Inc. and its affiliates. All Rights Reserved.
#
# Licensed under the MIT License. See the LICENSE accompanying this file
# for the specific language governing permissions and limitations under
# the License.
#
#
# Copy this script to /sbin/mount.efs and make sure it is executable.
#
# You will be able to mount an EFS file system by its short name, by adding it
# to /etc/fstab. The syntax of an fstab entry is:
#
# [Device] [Mount Point] [File System Type] [Options] [Dump] [Pass]
#
# Add an entry like this:
#
#   fs-deadbeef     /mount_point    efs     _netdev         0   0
#
# Using the 'efs' type will cause '/sbin/mount.efs' to be called by 'mount -a'
# for this file system. The '_netdev' option tells the init system that the
# 'efs' type is a networked file system type. This has been tested with systemd
# (Amazon Linux 2, CentOS 7, RHEL 7, Debian 9, and Ubuntu 16.04), and upstart
# (Amazon Linux 2017.09).
#
# Once there is an entry in fstab, the file system can be mounted with:
#
#   sudo mount /mount_point
#
# The script will add recommended mount options, if not provided in fstab.

33
import base64
34
import errno
35
36
import hashlib
import hmac
Max Beckett's avatar
Max Beckett committed
37
38
39
import json
import logging
import os
40
import pwd
Max Beckett's avatar
Max Beckett committed
41
42
43
44
45
46
import random
import re
import socket
import subprocess
import sys
import threading
47
import time
Max Beckett's avatar
Max Beckett committed
48
49

from contextlib import contextmanager
50
from datetime import datetime, timedelta
Max Beckett's avatar
Max Beckett committed
51
52
from logging.handlers import RotatingFileHandler

Yuan Gao's avatar
Yuan Gao committed
53
try:
54
55
56
57
    import ConfigParser
    from ConfigParser import NoOptionError, NoSectionError
except ImportError:
    from configparser import ConfigParser, NoOptionError, NoSectionError
Yuan Gao's avatar
Yuan Gao committed
58

Max Beckett's avatar
Max Beckett committed
59
try:
60
    from urllib.parse import quote_plus
Max Beckett's avatar
Max Beckett committed
61
except ImportError:
62
    from urllib import quote_plus
Max Beckett's avatar
Max Beckett committed
63
64

try:
65
    from urllib2 import URLError, HTTPError, build_opener, urlopen, Request, HTTPHandler
Max Beckett's avatar
Max Beckett committed
66
except ImportError:
67
68
    from urllib.request import urlopen, Request
    from urllib.error import URLError, HTTPError
Max Beckett's avatar
Max Beckett committed
69

70

71
VERSION = '1.25'
72
SERVICE = 'elasticfilesystem'
Max Beckett's avatar
Max Beckett committed
73
74
75

CONFIG_FILE = '/etc/amazon/efs/efs-utils.conf'
CONFIG_SECTION = 'mount'
76
77
CLIENT_INFO_SECTION = 'client-info'
CLIENT_SOURCE_STR_LEN_LIMIT = 100
Max Beckett's avatar
Max Beckett committed
78
79
80
81
82
83

LOG_DIR = '/var/log/amazon/efs'
LOG_FILE = 'mount.log'

STATE_FILE_DIR = '/var/run/efs'

84
85
86
87
88
PRIVATE_KEY_FILE = '/etc/amazon/efs/privateKey.pem'
DATE_ONLY_FORMAT = '%Y%m%d'
SIGV4_DATETIME_FORMAT = '%Y%m%dT%H%M%SZ'
CERT_DATETIME_FORMAT = '%y%m%d%H%M%SZ'

89
90
91
AWS_CREDENTIALS_FILE = os.path.expanduser(os.path.join('~' + pwd.getpwuid(os.getuid()).pw_name, '.aws', 'credentials'))
AWS_CONFIG_FILE = os.path.expanduser(os.path.join('~' + pwd.getpwuid(os.getuid()).pw_name, '.aws', 'config'))

92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
CA_CONFIG_BODY = """dir = %s
RANDFILE = $dir/database/.rand

[ ca ]
default_ca = local_ca

[ local_ca ]
database = $dir/database/index.txt
serial = $dir/database/serial
private_key = %s
cert = $dir/certificate.pem
new_certs_dir = $dir/certs
default_md = sha256
preserve = no
policy = efsPolicy
x509_extensions = v3_ca

[ efsPolicy ]
CN = supplied

[ req ]
prompt = no
distinguished_name = req_distinguished_name

[ req_distinguished_name ]
CN = %s

%s

121
122
%s

123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
%s
"""

# SigV4 Auth
ALGORITHM = 'AWS4-HMAC-SHA256'
AWS4_REQUEST = 'aws4_request'

HTTP_REQUEST_METHOD = 'GET'
CANONICAL_URI = '/'
CANONICAL_HEADERS_DICT = {
    'host': '%s'
}
CANONICAL_HEADERS = '\n'.join(['%s:%s' % (k, v) for k, v in sorted(CANONICAL_HEADERS_DICT.items())])
SIGNED_HEADERS = ';'.join(CANONICAL_HEADERS_DICT.keys())
REQUEST_PAYLOAD = ''

139
FS_ID_RE = re.compile('^(?P<fs_id>fs-[0-9a-f]+)$')
140
EFS_FQDN_RE = re.compile(r'^(?P<fs_id>fs-[0-9a-f]+)\.efs\.(?P<region>[a-z0-9-]+)\.(?P<dns_name_suffix>[a-z0-9.]+)$')
141
AP_ID_RE = re.compile('^fsap-[0-9a-f]{17}$')
Max Beckett's avatar
Max Beckett committed
142

143
144
CREDENTIALS_KEYS = ['AccessKeyId', 'SecretAccessKey', 'Token']
ECS_URI_ENV = 'AWS_CONTAINER_CREDENTIALS_RELATIVE_URI'
145
146
ECS_TASK_METADATA_API = 'http://169.254.170.2'
INSTANCE_METADATA_TOKEN_URL = 'http://169.254.169.254/latest/api/token'
Max Beckett's avatar
Max Beckett committed
147
INSTANCE_METADATA_SERVICE_URL = 'http://169.254.169.254/latest/dynamic/instance-identity/document/'
148
149
150
INSTANCE_IAM_URL = 'http://169.254.169.254/latest/meta-data/iam/security-credentials/'
SECURITY_CREDS_ECS_URI_HELP_URL = 'https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html'
SECURITY_CREDS_IAM_ROLE_HELP_URL = 'https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html'
Max Beckett's avatar
Max Beckett committed
151
152

DEFAULT_STUNNEL_VERIFY_LEVEL = 2
Ian Patel's avatar
Ian Patel committed
153
DEFAULT_STUNNEL_CAFILE = '/etc/amazon/efs/efs-utils.crt'
Max Beckett's avatar
Max Beckett committed
154

155
156
157
NOT_BEFORE_MINS = 15
NOT_AFTER_HOURS = 3

Max Beckett's avatar
Max Beckett committed
158
EFS_ONLY_OPTIONS = [
159
    'accesspoint',
160
    'awscredsuri',
161
162
    'awsprofile',
    'cafile',
163
164
165
166
    'iam',
    'netns',
    'noocsp',
    'ocsp',
Max Beckett's avatar
Max Beckett committed
167
168
    'tls',
    'tlsport',
169
    'verify'
Max Beckett's avatar
Max Beckett committed
170
171
]

172
UNSUPPORTED_OPTIONS = [
173
    'capath'
174
175
]

Max Beckett's avatar
Max Beckett committed
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
STUNNEL_GLOBAL_CONFIG = {
    'fips': 'no',
    'foreground': 'yes',
    'socket': [
        'l:SO_REUSEADDR=yes',
        'a:SO_BINDTODEVICE=lo',
    ],
}

STUNNEL_EFS_CONFIG = {
    'client': 'yes',
    'accept': '127.0.0.1:%s',
    'connect': '%s:2049',
    'sslVersion': 'TLSv1.2',
    'renegotiation': 'no',
    'TIMEOUTbusy': '20',
192
    'TIMEOUTclose': '0',
Max Beckett's avatar
Max Beckett committed
193
    'TIMEOUTidle': '70',
Ian Patel's avatar
Ian Patel committed
194
    'delay': 'yes',
Max Beckett's avatar
Max Beckett committed
195
196
197
}

WATCHDOG_SERVICE = 'amazon-efs-mount-watchdog'
Max Beckett's avatar
Max Beckett committed
198
199
SYSTEM_RELEASE_PATH = '/etc/system-release'
RHEL8_RELEASE_NAME = 'Red Hat Enterprise Linux release 8'
Yuan Gao's avatar
Yuan Gao committed
200
201
CENTOS8_RELEASE_NAME = 'CentOS Linux release 8'
SKIP_NO_LIBWRAP_RELEASES = [RHEL8_RELEASE_NAME, CENTOS8_RELEASE_NAME]
Max Beckett's avatar
Max Beckett committed
202
203
204
205
206
207
208
209
210
211
212


def fatal_error(user_message, log_message=None, exit_code=1):
    if log_message is None:
        log_message = user_message

    sys.stderr.write('%s\n' % user_message)
    logging.error(log_message)
    sys.exit(exit_code)


213
def get_target_region(config):
Max Beckett's avatar
Max Beckett committed
214
    def _fatal_error(message):
215
216
217
218
219
220
221
222
223
224
225
226
        fatal_error('Error retrieving region. Please set the "region" parameter in the efs-utils configuration file.', message)

    metadata_exception = 'Unknown error'
    try:
        return config.get(CONFIG_SECTION, 'region')
    except NoOptionError:
        pass

    try:
        return get_region_from_instance_metadata()
    except Exception as e:
        metadata_exception = e
Yuan Gao's avatar
Yuan Gao committed
227
228
        logging.warning('Region not found in config file and metadata service call failed, falling back '
                        'to legacy "dns_name_format" check')
Max Beckett's avatar
Max Beckett committed
229

230
231
232
233
234
235
    try:
        region = get_region_from_legacy_dns_format(config)
        sys.stdout.write('Warning: region obtained from "dns_name_format" field. Please set the "region" '
                         'parameter in the efs-utils configuration file.')
        return region
    except Exception:
Yuan Gao's avatar
Yuan Gao committed
236
        logging.warning('Legacy check for region in "dns_name_format" failed')
237
238
239
240
241
242

    _fatal_error(metadata_exception)


def get_region_from_instance_metadata():
    err_msg = None
Max Beckett's avatar
Max Beckett committed
243
    try:
244
245
        headers = {}
        instance_identity = get_aws_ec2_metadata(headers)
Max Beckett's avatar
Max Beckett committed
246
        return instance_identity['region']
247
248
249
250
251
252
253
254
255
256
257
    except HTTPError as e:
        # 401:Unauthorized, the GET request uses an invalid token, so generate a new one
        if e.code == 401:
            token = get_aws_ec2_metadata_token()
            headers = {'X-aws-ec2-metadata-token': token}
            instance_identity = get_aws_ec2_metadata(headers)
            return instance_identity['region']
        err_msg = 'Unable to reach instance metadata service at %s: status=%d, reason is %s' \
                  % (INSTANCE_METADATA_SERVICE_URL, e.code, e.reason)
    except URLError as e:
        err_msg = 'Unable to reach instance metadata service at %s, reason is %s' % (INSTANCE_METADATA_SERVICE_URL, e.reason)
Max Beckett's avatar
Max Beckett committed
258
    except ValueError as e:
259
        err_msg = 'Error parsing json: %s' % (e,)
Max Beckett's avatar
Max Beckett committed
260
    except KeyError as e:
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
        err_msg = 'Region not present in %s: %s' % (instance_identity, e)

    if err_msg:
        raise Exception(err_msg)


def get_region_from_legacy_dns_format(config):
    """
    For backwards compatibility check dns_name_format to obtain the target region. This functionality
    should only be used if region is not present in the config file and metadata calls fail.
    """
    dns_name_format = config.get(CONFIG_SECTION, 'dns_name_format')
    if '{region}' not in dns_name_format:
        split_dns_name_format = dns_name_format.split('.')
        if '{dns_name_suffix}' in dns_name_format:
            return split_dns_name_format[-2]
        elif 'amazonaws.com' in dns_name_format:
            return split_dns_name_format[-3]
    raise Exception('Region not found in dns_name_format')
Max Beckett's avatar
Max Beckett committed
280
281


282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
def get_aws_ec2_metadata_token():
    try:
        opener = build_opener(HTTPHandler)
        request = Request(INSTANCE_METADATA_TOKEN_URL)
        request.add_header('X-aws-ec2-metadata-token-ttl-seconds', 21600)
        request.get_method = lambda: 'PUT'
        res = opener.open(request)
        return res.read()
    except NameError:
        headers = {'X-aws-ec2-metadata-token-ttl-seconds': 21600}
        req = Request(INSTANCE_METADATA_TOKEN_URL, headers=headers, method='PUT')
        res = urlopen(req)
        return res.read()


def get_aws_ec2_metadata(headers):
    request = Request(INSTANCE_METADATA_SERVICE_URL, headers=headers)
    response = urlopen(request, timeout=1)
    data = response.read()
    if type(data) is str:
        instance_identity = json.loads(data)
    else:
        instance_identity = json.loads(data.decode(response.headers.get_content_charset() or 'us-ascii'))
    return instance_identity


308
def get_aws_security_credentials(use_iam, awsprofile=None, aws_creds_uri=None):
309
310
311
312
313
    """
    Lookup AWS security credentials (access key ID and secret access key). Adapted credentials provider chain from:
    https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html and
    https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/credentials.html
    """
314
315
316
    if not use_iam:
        return None, None

317
318
319
320
321
322
    # attempt to lookup AWS security credentials through the credentials URI the ECS agent generated
    if aws_creds_uri:
        return get_aws_security_credentials_from_ecs(aws_creds_uri, True)

    # attempt to lookup AWS security credentials in AWS credentials file (~/.aws/credentials)
    # and configs file (~/.aws/config) with given awsprofile
323
    if awsprofile:
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
        return get_aws_security_credentials_from_awsprofile(awsprofile, True)

    # attempt to lookup AWS security credentials through AWS_CONTAINER_CREDENTIALS_RELATIVE_URI environment variable
    if ECS_URI_ENV in os.environ:
        credentials, credentials_source = get_aws_security_credentials_from_ecs(os.environ[ECS_URI_ENV], False)
        if credentials and credentials_source:
            return credentials, credentials_source

    # attempt to lookup AWS security credentials with IAM role name attached to instance
    # through IAM role name security credentials lookup uri
    iam_role_name = get_iam_role_name()
    if iam_role_name:
        credentials, credentials_source = get_aws_security_credentials_from_instance_metadata(iam_role_name)
        if credentials and credentials_source:
            return credentials, credentials_source
339

340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
    error_msg = 'AWS Access Key ID and Secret Access Key are not found in AWS credentials file (%s), config file (%s), ' \
                'from ECS credentials relative uri, or from the instance security credentials service' % \
                (AWS_CREDENTIALS_FILE, AWS_CONFIG_FILE)
    fatal_error(error_msg, error_msg)


def get_aws_security_credentials_from_awsprofile(awsprofile, is_fatal=False):
    for file_path in [AWS_CREDENTIALS_FILE, AWS_CONFIG_FILE]:
        if os.path.exists(file_path):
            credentials = credentials_file_helper(file_path, awsprofile)
            if credentials['AccessKeyId']:
                return credentials, os.path.basename(file_path) + ':' + awsprofile

    # Fail if credentials cannot be fetched from the given awsprofile
    if is_fatal:
355
        log_message = 'AWS security credentials not found in %s or %s under named profile [%s]' % \
356
                    (AWS_CREDENTIALS_FILE, AWS_CONFIG_FILE, awsprofile)
357
        fatal_error(log_message)
358
359
    else:
        return None, None
360

361

362
363
364
365
366
367
def get_aws_security_credentials_from_ecs(aws_creds_uri, is_fatal=False):
    ecs_uri = ECS_TASK_METADATA_API + aws_creds_uri
    ecs_unsuccessful_resp = 'Unsuccessful retrieval of AWS security credentials at %s.' % ecs_uri
    ecs_url_error_msg = 'Unable to reach %s to retrieve AWS security credentials. See %s for more info.' \
                        % (ecs_uri, SECURITY_CREDS_ECS_URI_HELP_URL)
    ecs_security_dict = url_request_helper(ecs_uri, ecs_unsuccessful_resp, ecs_url_error_msg)
368

369
370
    if ecs_security_dict and all(k in ecs_security_dict for k in CREDENTIALS_KEYS):
        return ecs_security_dict, 'ecs:' + aws_creds_uri
371

372
373
374
375
376
377
378
379
    # Fail if credentials cannot be fetched from the given aws_creds_uri
    if is_fatal:
        fatal_error(ecs_unsuccessful_resp, ecs_unsuccessful_resp)
    else:
        return None, None


def get_aws_security_credentials_from_instance_metadata(iam_role_name):
Yuan Gao's avatar
Yuan Gao committed
380
    security_creds_lookup_url = INSTANCE_IAM_URL + iam_role_name
381
    unsuccessful_resp = 'Unsuccessful retrieval of AWS security credentials at %s.' % security_creds_lookup_url
Yuan Gao's avatar
Yuan Gao committed
382
383
    url_error_msg = 'Unable to reach %s to retrieve AWS security credentials. See %s for more info.' % \
                    (security_creds_lookup_url, SECURITY_CREDS_IAM_ROLE_HELP_URL)
384
385
386
387
388
389
390
391
392
    iam_security_dict = url_request_helper(security_creds_lookup_url, unsuccessful_resp, url_error_msg)

    if iam_security_dict and all(k in iam_security_dict for k in CREDENTIALS_KEYS):
        return iam_security_dict, 'metadata:'
    else:
        return None, None


def get_iam_role_name():
393
    iam_role_unsuccessful_resp = 'Unsuccessful retrieval of IAM role name at %s.' % INSTANCE_IAM_URL
Yuan Gao's avatar
Yuan Gao committed
394
395
    iam_role_url_error_msg = 'Unable to reach %s to retrieve IAM role name. See %s for more info.' % \
                             (INSTANCE_IAM_URL, SECURITY_CREDS_IAM_ROLE_HELP_URL)
396
    iam_role_name = url_request_helper(INSTANCE_IAM_URL, iam_role_unsuccessful_resp, iam_role_url_error_msg)
397
    return iam_role_name
398
399


400
def credentials_file_helper(file_path, awsprofile):
401
402
403
404
    aws_credentials_configs = read_config(file_path)
    credentials = {'AccessKeyId': None, 'SecretAccessKey': None, 'Token': None}

    try:
405
406
407
        access_key = aws_credentials_configs.get(awsprofile, 'aws_access_key_id')
        secret_key = aws_credentials_configs.get(awsprofile, 'aws_secret_access_key')
        session_token = aws_credentials_configs.get(awsprofile, 'aws_session_token')
408
409
410
411
412
413

        credentials['AccessKeyId'] = access_key
        credentials['SecretAccessKey'] = secret_key
        credentials['Token'] = session_token
    except NoOptionError as e:
        if 'aws_access_key_id' in str(e) or 'aws_secret_access_key' in str(e):
414
415
            logging.debug('aws_access_key_id or aws_secret_access_key not found in %s under named profile [%s]', file_path,
                          awsprofile)
416
417
        if 'aws_session_token' in str(e):
            logging.debug('aws_session_token not found in %s', file_path)
418
419
            credentials['AccessKeyId'] = aws_credentials_configs.get(awsprofile, 'aws_access_key_id')
            credentials['SecretAccessKey'] = aws_credentials_configs.get(awsprofile, 'aws_secret_access_key')
420
    except NoSectionError:
421
        logging.debug('No [%s] section found in config file %s', awsprofile, file_path)
422
423
424
425

    return credentials


426
427
428
429
430
def get_aws_profile(options, use_iam):
    awsprofile = options.get('awsprofile')
    if not awsprofile and use_iam:
        for file_path in [AWS_CREDENTIALS_FILE, AWS_CONFIG_FILE]:
            aws_credentials_configs = read_config(file_path)
431
432
433
434
435
436
437
            # check if aws access key id is found under [default] section in current file and return 'default' if so
            try:
                access_key = aws_credentials_configs.get('default', 'aws_access_key_id')
                if access_key is not None:
                    return 'default'
            except (NoSectionError, NoOptionError):
                continue
438
439

    return awsprofile
440
441
442
443
444
445
446
447
448
449
450


def url_request_helper(url, unsuccessful_resp, url_error_msg):
    try:
        request_resp = urlopen(url, timeout=1)

        if request_resp.getcode() != 200:
            logging.debug(unsuccessful_resp + ' %s: ResponseCode=%d', url, request_resp.getcode())
            return None

        resp_body = request_resp.read()
Yuan Gao's avatar
Yuan Gao committed
451
        resp_body_type = type(resp_body)
452
        try:
Yuan Gao's avatar
Yuan Gao committed
453
            if resp_body_type is str:
454
455
456
457
458
459
                resp_dict = json.loads(resp_body)
            else:
                resp_dict = json.loads(resp_body.decode(request_resp.headers.get_content_charset() or 'us-ascii'))

            return resp_dict
        except ValueError as e:
Yuan Gao's avatar
Yuan Gao committed
460
461
            logging.info('ValueError parsing "%s" into json: %s. Returning response body.' % (str(resp_body), e))
            return resp_body if resp_body_type is str else resp_body.decode('utf-8')
462
463
464
465
466
    except URLError as e:
        logging.debug('%s %s', url_error_msg, e)
        return None


Max Beckett's avatar
Max Beckett committed
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
def parse_options(options):
    opts = {}
    for o in options.split(','):
        if '=' in o:
            k, v = o.split('=')
            opts[k] = v
        else:
            opts[o] = None
    return opts


def get_tls_port_range(config):
    lower_bound = config.getint(CONFIG_SECTION, 'port_range_lower_bound')
    upper_bound = config.getint(CONFIG_SECTION, 'port_range_upper_bound')

    if lower_bound >= upper_bound:
        fatal_error('Configuration option "port_range_upper_bound" defined as %d '
                    'must be strictly greater than "port_range_lower_bound" defined as %d.'
                    % (upper_bound, lower_bound))

    return lower_bound, upper_bound


490
491
def choose_tls_port(config, options):
    if 'tlsport' in options:
492
        ports_to_try = [int(options['tlsport'])]
493
494
    else:
        lower_bound, upper_bound = get_tls_port_range(config)
Max Beckett's avatar
Max Beckett committed
495

496
        tls_ports = list(range(lower_bound, upper_bound))
Max Beckett's avatar
Max Beckett committed
497

498
499
        # Choose a random midpoint, and then try ports in-order from there
        mid = random.randrange(len(tls_ports))
Max Beckett's avatar
Max Beckett committed
500

501
502
        ports_to_try = tls_ports[mid:] + tls_ports[:mid]
        assert len(tls_ports) == len(ports_to_try)
Max Beckett's avatar
Max Beckett committed
503

504
    sock = socket.socket()
Max Beckett's avatar
Max Beckett committed
505
506
507
508
509
510
511
512
    for tls_port in ports_to_try:
        try:
            sock.bind(('localhost', tls_port))
            sock.close()
            return tls_port
        except socket.error:
            continue

513
514
    sock.close()

515
516
517
518
519
520
521
522
    if 'tlsport' in options:
        fatal_error('Specified port [%s] is unavailable. Try selecting a different port.' % options['tlsport'])
    else:
        fatal_error('Failed to locate an available port in the range [%d, %d], try specifying a different port range in %s'
                    % (lower_bound, upper_bound, CONFIG_FILE))


def is_ocsp_enabled(config, options):
523
    if 'ocsp' in options:
524
525
526
527
528
        return True
    elif 'noocsp' in options:
        return False
    else:
        return config.getboolean(CONFIG_SECTION, 'stunnel_check_cert_validity')
Max Beckett's avatar
Max Beckett committed
529
530
531


def get_mount_specific_filename(fs_id, mountpoint, tls_port):
Ian Patel's avatar
Ian Patel committed
532
    return '%s.%s.%d' % (fs_id, os.path.abspath(mountpoint).replace(os.sep, '.').lstrip('.'), tls_port)
Max Beckett's avatar
Max Beckett committed
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550


def serialize_stunnel_config(config, header=None):
    lines = []

    if header:
        lines.append('[%s]' % header)

    for k, v in config.items():
        if type(v) is list:
            for item in v:
                lines.append('%s = %s' % (k, item))
        else:
            lines.append('%s = %s' % (k, v))

    return lines


551
552
553
554
555
556
557
558
559
560
def add_stunnel_ca_options(efs_config, config, options):
    if 'cafile' in options:
        stunnel_cafile = options['cafile']
    else:
        try:
            stunnel_cafile = config.get(CONFIG_SECTION, 'stunnel_cafile')
        except NoOptionError:
            logging.debug('No CA file configured, using default CA file %s', DEFAULT_STUNNEL_CAFILE)
            stunnel_cafile = DEFAULT_STUNNEL_CAFILE

Ian Patel's avatar
Ian Patel committed
561
    if not os.path.exists(stunnel_cafile):
562
563
564
        fatal_error('Failed to find certificate authority file for verification',
                    'Failed to find CAfile "%s"' % stunnel_cafile)

Ian Patel's avatar
Ian Patel committed
565
566
567
568
569
570
571
572
573
574
575
    efs_config['CAfile'] = stunnel_cafile


def is_stunnel_option_supported(stunnel_output, stunnel_option_name):
    supported = False
    for line in stunnel_output:
        if line.startswith(stunnel_option_name):
            supported = True
            break

    if not supported:
Yuan Gao's avatar
Yuan Gao committed
576
        logging.warning('stunnel does not support "%s"', stunnel_option_name)
Ian Patel's avatar
Ian Patel committed
577
578
579
580

    return supported


581
582
583
def get_version_specific_stunnel_options():
    stunnel_command = [_stunnel_bin(), '-help']
    proc = subprocess.Popen(stunnel_command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
Ian Patel's avatar
Ian Patel committed
584
585
    proc.wait()
    _, err = proc.communicate()
Max Beckett's avatar
Max Beckett committed
586

Ian Patel's avatar
Ian Patel committed
587
    stunnel_output = err.splitlines()
Max Beckett's avatar
Max Beckett committed
588

589
590
    check_host_supported = is_stunnel_option_supported(stunnel_output, b'checkHost')
    ocsp_aia_supported = is_stunnel_option_supported(stunnel_output, b'OCSPaia')
Ian Patel's avatar
Ian Patel committed
591

592
    return check_host_supported, ocsp_aia_supported
Ian Patel's avatar
Ian Patel committed
593
594


595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
def _stunnel_bin():
    return find_command_path('stunnel',
                             'Please install it following the instructions at '
                             'https://docs.aws.amazon.com/efs/latest/ug/using-amazon-efs-utils.html#upgrading-stunnel')


def find_command_path(command, install_method):
    try:
        env_path = '/sbin:/usr/sbin:/usr/local/sbin:/root/bin:/usr/local/bin:/usr/bin:/bin'
        os.putenv('PATH', env_path)
        path = subprocess.check_output(['which', command])
    except subprocess.CalledProcessError as e:
        fatal_error('Failed to locate %s in %s - %s' % (command, env_path, install_method), e)
    return path.strip().decode()


Max Beckett's avatar
Max Beckett committed
611
612
613
614
615
616
617
618
619
620
621
def get_system_release_version():
    system_release_version = 'unknown'
    try:
        with open(SYSTEM_RELEASE_PATH) as f:
            system_release_version = f.read().strip()
    except IOError:
        logging.debug('Unable to read %s', SYSTEM_RELEASE_PATH)

    return system_release_version


622
def write_stunnel_config_file(config, state_file_dir, fs_id, mountpoint, tls_port, dns_name, verify_level, ocsp_enabled,
623
                              options, log_dir=LOG_DIR, cert_details=None):
Max Beckett's avatar
Max Beckett committed
624
625
626
627
628
629
630
631
632
633
    """
    Serializes stunnel configuration to a file. Unfortunately this does not conform to Python's config file format, so we have to
    hand-serialize it.
    """

    mount_filename = get_mount_specific_filename(fs_id, mountpoint, tls_port)

    global_config = dict(STUNNEL_GLOBAL_CONFIG)
    if config.getboolean(CONFIG_SECTION, 'stunnel_debug_enabled'):
        global_config['debug'] = 'debug'
634
635
636
637
638

        if config.has_option(CONFIG_SECTION, 'stunnel_logs_file'):
            global_config['output'] = config.get(CONFIG_SECTION, 'stunnel_logs_file').replace('{fs_id}', fs_id)
        else:
            global_config['output'] = os.path.join(log_dir, '%s.stunnel.log' % mount_filename)
Max Beckett's avatar
Max Beckett committed
639
640
641
642

    efs_config = dict(STUNNEL_EFS_CONFIG)
    efs_config['accept'] = efs_config['accept'] % tls_port
    efs_config['connect'] = efs_config['connect'] % dns_name
Ian Patel's avatar
Ian Patel committed
643
644
    efs_config['verify'] = verify_level
    if verify_level > 0:
645
646
647
648
649
        add_stunnel_ca_options(efs_config, config, options)

    if cert_details:
        efs_config['cert'] = cert_details['certificate']
        efs_config['key'] = cert_details['privateKey']
Ian Patel's avatar
Ian Patel committed
650

651
    check_host_supported, ocsp_aia_supported = get_version_specific_stunnel_options()
Ian Patel's avatar
Ian Patel committed
652
653
654
655

    tls_controls_message = 'WARNING: Your client lacks sufficient controls to properly enforce TLS. Please upgrade stunnel, ' \
        'or disable "%%s" in %s.\nSee %s for more detail.' % (CONFIG_FILE,
                                                              'https://docs.aws.amazon.com/console/efs/troubleshooting-tls')
Max Beckett's avatar
Max Beckett committed
656

657
658
659
660
661
    if config.getboolean(CONFIG_SECTION, 'stunnel_check_cert_hostname'):
        if check_host_supported:
            efs_config['checkHost'] = dns_name
        else:
            fatal_error(tls_controls_message % 'stunnel_check_cert_hostname')
Max Beckett's avatar
Max Beckett committed
662

663
664
    # Only use the config setting if the override is not set
    if ocsp_enabled:
665
666
667
668
        if ocsp_aia_supported:
            efs_config['OCSPaia'] = 'yes'
        else:
            fatal_error(tls_controls_message % 'stunnel_check_cert_validity')
Max Beckett's avatar
Max Beckett committed
669

Yuan Gao's avatar
Yuan Gao committed
670
671
    system_release_version = get_system_release_version()
    if not any(release in system_release_version for release in SKIP_NO_LIBWRAP_RELEASES):
Max Beckett's avatar
Max Beckett committed
672
673
        efs_config['libwrap'] = 'no'

Max Beckett's avatar
Max Beckett committed
674
675
676
677
678
679
680
681
682
683
684
    stunnel_config = '\n'.join(serialize_stunnel_config(global_config) + serialize_stunnel_config(efs_config, 'efs'))
    logging.debug('Writing stunnel configuration:\n%s', stunnel_config)

    stunnel_config_file = os.path.join(state_file_dir, 'stunnel-config.%s' % mount_filename)

    with open(stunnel_config_file, 'w') as f:
        f.write(stunnel_config)

    return stunnel_config_file


685
def write_tls_tunnel_state_file(fs_id, mountpoint, tls_port, tunnel_pid, command, files, state_file_dir, cert_details=None):
Max Beckett's avatar
Max Beckett committed
686
687
688
689
690
691
692
693
694
695
696
697
    """
    Return the name of the temporary file containing TLS tunnel state, prefixed with a '~'. This file needs to be renamed to a
    non-temporary version following a successful mount.
    """
    state_file = '~' + get_mount_specific_filename(fs_id, mountpoint, tls_port)

    state = {
        'pid': tunnel_pid,
        'cmd': command,
        'files': files,
    }

698
699
700
    if cert_details:
        state.update(cert_details)

Max Beckett's avatar
Max Beckett committed
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
    with open(os.path.join(state_file_dir, state_file), 'w') as f:
        json.dump(state, f)

    return state_file


def test_tunnel_process(tunnel_proc, fs_id):
    tunnel_proc.poll()
    if tunnel_proc.returncode is not None:
        out, err = tunnel_proc.communicate()
        fatal_error('Failed to initialize TLS tunnel for %s' % fs_id,
                    'Failed to start TLS tunnel (errno=%d). stdout="%s" stderr="%s"'
                    % (tunnel_proc.returncode, out.strip(), err.strip()))


def poll_tunnel_process(tunnel_proc, fs_id, mount_completed):
    """
    poll the tunnel process health every .5s during the mount attempt to fail fast if the tunnel dies - since this is not called
    from the main thread, if the tunnel fails, exit uncleanly with os._exit
    """
    while not mount_completed.is_set():
        try:
            test_tunnel_process(tunnel_proc, fs_id)
        except SystemExit as e:
            os._exit(e.code)
        mount_completed.wait(.5)


def get_init_system(comm_file='/proc/1/comm'):
    init_system = 'unknown'
    try:
        with open(comm_file) as f:
            init_system = f.read().strip()
    except IOError:
        logging.warning('Unable to read %s', comm_file)

    logging.debug('Identified init system: %s', init_system)
    return init_system


Yuan Gao's avatar
Yuan Gao committed
741
def check_network_target(fs_id):
Max Beckett's avatar
Max Beckett committed
742
    with open(os.devnull, 'w') as devnull:
743
        rc = subprocess.call(['systemctl', 'status', 'network.target'], stdout=devnull, stderr=devnull, close_fds=True)
Max Beckett's avatar
Max Beckett committed
744
745
746
747
748
749

    if rc != 0:
        fatal_error('Failed to mount %s because the network was not yet available, add "_netdev" to your mount options' % fs_id,
                    exit_code=0)


Yuan Gao's avatar
Yuan Gao committed
750
751
752
753
754
755
756
757
def check_network_status(fs_id, init_system):
    if init_system != 'systemd':
        logging.debug('Not testing network on non-systemd init systems')
        return

    check_network_target(fs_id)


Max Beckett's avatar
Max Beckett committed
758
759
def start_watchdog(init_system):
    if init_system == 'init':
760
761
        proc = subprocess.Popen(
                ['/sbin/status', WATCHDOG_SERVICE], stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
Ian Patel's avatar
Ian Patel committed
762
        status, _ = proc.communicate()
Max Beckett's avatar
Max Beckett committed
763
764
        if 'stop' in status:
            with open(os.devnull, 'w') as devnull:
765
                subprocess.Popen(['/sbin/start', WATCHDOG_SERVICE], stdout=devnull, stderr=devnull, close_fds=True)
Max Beckett's avatar
Max Beckett committed
766
767
768
769
        elif 'start' in status:
            logging.debug('%s is already running', WATCHDOG_SERVICE)

    elif init_system == 'systemd':
770
        rc = subprocess.call(['systemctl', 'is-active', '--quiet', WATCHDOG_SERVICE], close_fds=True)
Max Beckett's avatar
Max Beckett committed
771
772
        if rc != 0:
            with open(os.devnull, 'w') as devnull:
773
                subprocess.Popen(['systemctl', 'start', WATCHDOG_SERVICE], stdout=devnull, stderr=devnull, close_fds=True)
Max Beckett's avatar
Max Beckett committed
774
775
776
777
778
779
780
781
782
        else:
            logging.debug('%s is already running', WATCHDOG_SERVICE)

    else:
        error_message = 'Could not start %s, unrecognized init system "%s"' % (WATCHDOG_SERVICE, init_system)
        sys.stderr.write('%s\n' % error_message)
        logging.warning(error_message)


783
def create_required_directory(config, directory):
784
785
786
787
788
789
    mode = 0o750
    try:
        mode_str = config.get(CONFIG_SECTION, 'state_file_dir_mode')
        try:
            mode = int(mode_str, 8)
        except ValueError:
Yuan Gao's avatar
Yuan Gao committed
790
791
            logging.warning('Bad state_file_dir_mode "%s" in config file "%s"', mode_str, CONFIG_FILE)
    except NoOptionError:
792
793
        pass

794
    try:
795
        os.makedirs(directory, mode)
796
    except OSError as e:
797
        if errno.EEXIST != e.errno or not os.path.isdir(directory):
798
            raise
799
800


Max Beckett's avatar
Max Beckett committed
801
@contextmanager
802
def bootstrap_tls(config, init_system, dns_name, fs_id, mountpoint, options, state_file_dir=STATE_FILE_DIR):
803
804
805
    tls_port = choose_tls_port(config, options)
    # override the tlsport option so that we can later override the port the NFS client uses to connect to stunnel.
    # if the user has specified tlsport=X at the command line this will just re-set tlsport to X.
Max Beckett's avatar
Max Beckett committed
806
    options['tlsport'] = tls_port
807

808
    use_iam = 'iam' in options
809
    ap_id = options.get('accesspoint')
810
    cert_details = {}
811
812
    security_credentials = None
    client_info = get_client_info(config)
813

814
    if use_iam:
815
816
817
818
819
820
821
        aws_creds_uri = options.get('awscredsuri')
        if aws_creds_uri:
            kwargs = {'aws_creds_uri': aws_creds_uri}
        else:
            kwargs = {'awsprofile': get_aws_profile(options, use_iam)}

        security_credentials, credentials_source = get_aws_security_credentials(use_iam, **kwargs)
822
823
824

        if credentials_source:
            cert_details['awsCredentialsMethod'] = credentials_source
825

826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
    if ap_id:
        cert_details['accessPoint'] = ap_id

    # additional symbol appended to avoid naming collisions
    cert_details['mountStateDir'] = get_mount_specific_filename(fs_id, mountpoint, tls_port) + '+'
    # common name for certificate signing request is max 64 characters
    cert_details['commonName'] = socket.gethostname()[0:64]
    cert_details['region'] = get_target_region(config)
    cert_details['certificateCreationTime'] = create_certificate(config, cert_details['mountStateDir'],
                                                                 cert_details['commonName'], cert_details['region'], fs_id,
                                                                 security_credentials, ap_id, client_info,
                                                                 base_path=state_file_dir)
    cert_details['certificate'] = os.path.join(state_file_dir, cert_details['mountStateDir'], 'certificate.pem')
    cert_details['privateKey'] = get_private_key_path()
    cert_details['fsId'] = fs_id
841
842
843
844
845
846

    start_watchdog(init_system)

    if not os.path.exists(state_file_dir):
        create_required_directory(config, state_file_dir)

Ian Patel's avatar
Ian Patel committed
847
    verify_level = int(options.get('verify', DEFAULT_STUNNEL_VERIFY_LEVEL))
848
    ocsp_enabled = is_ocsp_enabled(config, options)
Max Beckett's avatar
Max Beckett committed
849

850
    stunnel_config_file = write_stunnel_config_file(config, state_file_dir, fs_id, mountpoint, tls_port, dns_name, verify_level,
851
                                                    ocsp_enabled, options, cert_details=cert_details)
852
    tunnel_args = [_stunnel_bin(), stunnel_config_file]
853
854
    if 'netns' in options:
        tunnel_args = ['nsenter', '--net=' + options['netns']] + tunnel_args
Max Beckett's avatar
Max Beckett committed
855
856
857

    # launch the tunnel in a process group so if it has any child processes, they can be killed easily by the mount watchdog
    logging.info('Starting TLS tunnel: "%s"', ' '.join(tunnel_args))
858
    tunnel_proc = subprocess.Popen(
859
        tunnel_args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, preexec_fn=os.setsid, close_fds=True)
Max Beckett's avatar
Max Beckett committed
860
861
862
    logging.info('Started TLS tunnel, pid: %d', tunnel_proc.pid)

    temp_tls_state_file = write_tls_tunnel_state_file(fs_id, mountpoint, tls_port, tunnel_proc.pid, tunnel_args,
863
                                                      [stunnel_config_file], state_file_dir, cert_details=cert_details)
Max Beckett's avatar
Max Beckett committed
864
865
866
867
868
869
870
871

    try:
        yield tunnel_proc
    finally:
        os.rename(os.path.join(state_file_dir, temp_tls_state_file), os.path.join(state_file_dir, temp_tls_state_file[1:]))


def get_nfs_mount_options(options):
872
    # If you change these options, update the man page as well at man/mount.efs.8
Max Beckett's avatar
Max Beckett committed
873
874
875
876
877
878
879
880
881
882
883
884
    if 'nfsvers' not in options and 'vers' not in options:
        options['nfsvers'] = '4.1'
    if 'rsize' not in options:
        options['rsize'] = '1048576'
    if 'wsize' not in options:
        options['wsize'] = '1048576'
    if 'soft' not in options and 'hard' not in options:
        options['hard'] = None
    if 'timeo' not in options:
        options['timeo'] = '600'
    if 'retrans' not in options:
        options['retrans'] = '2'
885
886
    if 'noresvport' not in options:
        options['noresvport'] = None
Max Beckett's avatar
Max Beckett committed
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901

    if 'tls' in options:
        options['port'] = options['tlsport']

    def to_nfs_option(k, v):
        if v is None:
            return k
        return '%s=%s' % (str(k), str(v))

    nfs_options = [to_nfs_option(k, v) for k, v in options.items() if k not in EFS_ONLY_OPTIONS]

    return ','.join(nfs_options)


def mount_nfs(dns_name, path, mountpoint, options):
902

Max Beckett's avatar
Max Beckett committed
903
904
905
906
907
    if 'tls' in options:
        mount_path = '127.0.0.1:%s' % path
    else:
        mount_path = '%s:%s' % (dns_name, path)

Ian Patel's avatar
Ian Patel committed
908
    command = ['/sbin/mount.nfs4', mount_path, mountpoint, '-o', get_nfs_mount_options(options)]
Max Beckett's avatar
Max Beckett committed
909

910
911
912
    if 'netns' in options:
        command = ['nsenter', '--net=' + options['netns']] + command

Max Beckett's avatar
Max Beckett committed
913
914
    logging.info('Executing: "%s"', ' '.join(command))

915
    proc = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
Ian Patel's avatar
Ian Patel committed
916
    out, err = proc.communicate()
Max Beckett's avatar
Max Beckett committed
917

Ian Patel's avatar
Ian Patel committed
918
    if proc.returncode == 0:
Max Beckett's avatar
Max Beckett committed
919
920
        logging.info('Successfully mounted %s at %s', dns_name, mountpoint)
    else:
Ian Patel's avatar
Ian Patel committed
921
922
        message = 'Failed to mount %s at %s: returncode=%d, stderr="%s"' % (dns_name, mountpoint, proc.returncode, err.strip())
        fatal_error(err.strip(), message, proc.returncode)
Max Beckett's avatar
Max Beckett committed
923
924


Ian Patel's avatar
Ian Patel committed
925
926
927
928
929
930
931
def usage(out, exit_code=1):
    out.write('Usage: mount.efs [--version] [-h|--help] <fsname> <mountpoint> [-o <options>]\n')
    sys.exit(exit_code)


def parse_arguments_early_exit(args=None):
    """Parse arguments, checking for early exit conditions only"""
Max Beckett's avatar
Max Beckett committed
932
933
934
935
936
937
938
    if args is None:
        args = sys.argv

    if '-h' in args[1:] or '--help' in args[1:]:
        usage(out=sys.stdout, exit_code=0)

    if '--version' in args[1:]:
Ian Patel's avatar
Ian Patel committed
939
        sys.stdout.write('%s Version: %s\n' % (args[0], VERSION))
Max Beckett's avatar
Max Beckett committed
940
941
        sys.exit(0)

Ian Patel's avatar
Ian Patel committed
942
943
944
945
946
947

def parse_arguments(config, args=None):
    """Parse arguments, return (fsid, path, mountpoint, options)"""
    if args is None:
        args = sys.argv

Max Beckett's avatar
Max Beckett committed
948
949
950
951
952
953
954
955
    fsname = None
    mountpoint = None
    options = {}

    if len(args) > 1:
        fsname = args[1]
    if len(args) > 2:
        mountpoint = args[2]
956
957
958
    if len(args) > 4 and '-o' in args[:-1]:
        options_index = args.index('-o') + 1
        options = parse_options(args[options_index])
Max Beckett's avatar
Max Beckett committed
959
960

    if not fsname or not mountpoint:
Ian Patel's avatar
Ian Patel committed
961
        usage(out=sys.stderr)
Max Beckett's avatar
Max Beckett committed
962

963
    fs_id, path = match_device(config, fsname)
Max Beckett's avatar
Max Beckett committed
964
965
966
967

    return fs_id, path, mountpoint, options


968
969
970
971
972
973
974
975
976
977
978
979
def get_client_info(config):
    client_info = {}

    # source key/value pair in config file
    if config.has_option(CLIENT_INFO_SECTION, 'source'):
        client_source = config.get(CLIENT_INFO_SECTION, 'source')
        if 0 < len(client_source) <= CLIENT_SOURCE_STR_LEN_LIMIT:
            client_info['source'] = client_source

    return client_info


980
981
def create_certificate(config, mount_name, common_name, region, fs_id, security_credentials, ap_id, client_info,
                       base_path=STATE_FILE_DIR):
982
983
984
985
986
987
988
989
990
991
992
993
    current_time = get_utc_now()
    tls_paths = tls_paths_dictionary(mount_name, base_path)

    certificate_config = os.path.join(tls_paths['mount_dir'], 'config.conf')
    certificate_signing_request = os.path.join(tls_paths['mount_dir'], 'request.csr')
    certificate = os.path.join(tls_paths['mount_dir'], 'certificate.pem')

    ca_dirs_check(config, tls_paths['database_dir'], tls_paths['certs_dir'])
    ca_supporting_files_check(tls_paths['index'], tls_paths['index_attr'], tls_paths['serial'], tls_paths['rand'])

    private_key = check_and_create_private_key(base_path)

994
    if security_credentials:
995
996
997
        public_key = os.path.join(tls_paths['mount_dir'], 'publicKey.pem')
        create_public_key(private_key, public_key)

998
    create_ca_conf(certificate_config, common_name, tls_paths['mount_dir'], private_key, current_time, region, fs_id,
999
                   security_credentials, ap_id, client_info)
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
    create_certificate_signing_request(certificate_config, private_key, certificate_signing_request)

    not_before = get_certificate_timestamp(current_time, minutes=-NOT_BEFORE_MINS)
    not_after = get_certificate_timestamp(current_time, hours=NOT_AFTER_HOURS)

    cmd = 'openssl ca -startdate %s -enddate %s -selfsign -batch -notext -config %s -in %s -out %s' % \
          (not_before, not_after, certificate_config, certificate_signing_request, certificate)
    subprocess_call(cmd, 'Failed to create self-signed client-side certificate')
    return current_time.strftime(CERT_DATETIME_FORMAT)


def get_private_key_path():
    """Wrapped for mocking purposes in unit tests"""
    return PRIVATE_KEY_FILE


def check_and_create_private_key(base_path=STATE_FILE_DIR):
    # Creating RSA private keys is slow, so we will create one private key and allow mounts to share it.
    # This means, however, that we have to include a locking mechanism to ensure that the private key is
    # atomically created, as mounts occurring in parallel may try to create the key simultaneously.
    key = get_private_key_path()

    @contextmanager
    def open_lock_file():
        lock_file = os.path.join(base_path, 'efs-utils-lock')
        f = os.open(lock_file, os.O_CREAT | os.O_DSYNC | os.O_EXCL | os.O_RDWR)
        try:
            lock_file_contents = 'PID: %s' % os.getpid()
            os.write(f, lock_file_contents.encode('utf-8'))
            yield f
        finally:
            os.close(f)
            os.remove(lock_file)

    def do_with_lock(function):
        while True:
            try:
                with open_lock_file():
                    return function()
            except OSError as e:
                if e.errno == errno.EEXIST:
                    logging.info('Failed to take out private key creation lock, sleeping 50 ms')
                    time.sleep(0.05)
                else:
                    raise

    def generate_key():
        if os.path.isfile(key):
            return

        cmd = 'openssl genpkey -algorithm RSA -out %s -pkeyopt rsa_keygen_bits:3072' % key
        subprocess_call(cmd, 'Failed to create private key')
        read_only_mode = 0o400
        os.chmod(key, read_only_mode)

    do_with_lock(generate_key)
    return key


def create_certificate_signing_request(config_path, private_key, csr_path):
    cmd = 'openssl req -new -config %s -key %s -out %s' % (config_path, private_key, csr_path)
    subprocess_call(cmd, 'Failed to create certificate signing request (csr)')


1064
1065
def create_ca_conf(config_path, common_name, directory, private_key, date,
                   region, fs_id, security_credentials, ap_id, client_info):
1066
1067
    """Populate ca/req configuration file with fresh configurations at every mount since SigV4 signature can change"""
    public_key_path = os.path.join(directory, 'publicKey.pem')
1068
    ca_extension_body = ca_extension_builder(ap_id, security_credentials, fs_id, client_info)
1069
1070
1071
    efs_client_auth_body = efs_client_auth_builder(public_key_path, security_credentials['AccessKeyId'],
                                                   security_credentials['SecretAccessKey'], date, region, fs_id,
                                                   security_credentials['Token']) if security_credentials else ''
1072
1073
1074
    efs_client_info_body = efs_client_info_builder(client_info) if client_info else ''
    full_config_body = CA_CONFIG_BODY % (directory, private_key, common_name, ca_extension_body,
                                         efs_client_auth_body, efs_client_info_body)
1075
1076
1077
1078
1079
1080
1081

    with open(config_path, 'w') as f:
        f.write(full_config_body)

    return full_config_body


1082
def ca_extension_builder(ap_id, security_credentials, fs_id, client_info):
1083
1084
1085
    ca_extension_str = '[ v3_ca ]\nsubjectKeyIdentifier = hash'
    if ap_id:
        ca_extension_str += '\n1.3.6.1.4.1.4843.7.1 = ASN1:UTF8String:' + ap_id
1086
    if security_credentials:
1087
        ca_extension_str += '\n1.3.6.1.4.1.4843.7.2 = ASN1:SEQUENCE:efs_client_auth'
1088
1089

    ca_extension_str += '\n1.3.6.1.4.1.4843.7.3 = ASN1:UTF8String:' + fs_id
1090

1091
1092
1093
    if client_info:
        ca_extension_str += '\n1.3.6.1.4.1.4843.7.4 = ASN1:SEQUENCE:efs_client_info'

1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
    return ca_extension_str


def efs_client_auth_builder(public_key_path, access_key_id, secret_access_key, date, region, fs_id, session_token=None):
    public_key_hash = get_public_key_sha1(public_key_path)
    canonical_request = create_canonical_request(public_key_hash, date, access_key_id, region, fs_id, session_token)
    string_to_sign = create_string_to_sign(canonical_request, date, region)
    signature = calculate_signature(string_to_sign, date, secret_access_key, region)
    efs_client_auth_str = '[ efs_client_auth ]'
    efs_client_auth_str += '\naccessKeyId = UTF8String:' + access_key_id
    efs_client_auth_str += '\nsignature = OCTETSTRING:' + signature
    efs_client_auth_str += '\nsigv4DateTime = UTCTIME:' + date.strftime(CERT_DATETIME_FORMAT)

    if session_token:
        efs_client_auth_str += '\nsessionToken = EXPLICIT:0,UTF8String:' + session_token

    return efs_client_auth_str


1113
1114
1115
def efs_client_info_builder(client_info):
    efs_client_info_str = '[ efs_client_info ]'
    for key, value in client_info.items():
Yuan Gao's avatar
Yuan Gao committed
1116
        efs_client_info_str += '\n%s = UTF8String:%s' % (key, value)
1117
1118
1119
    return efs_client_info_str


1120
1121
1122
1123
1124
1125
1126
def create_public_key(private_key, public_key):
    cmd = 'openssl rsa -in %s -outform PEM -pubout -out %s' % (private_key, public_key)
    subprocess_call(cmd, 'Failed to create public key')


def subprocess_call(cmd, error_message):
    """Helper method to run shell openssl command and to handle response error messages"""
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
    retry_times = 3
    for retry in range(retry_times):
        process = subprocess.Popen(cmd.split(), stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True)
        (output, err) = process.communicate()
        rc = process.poll()
        if rc != 0:
            logging.error('Command %s failed, rc=%s, stdout="%s", stderr="%s"' % (cmd, rc, output, err), exc_info=True)
            process.kill()
        else:
            return output, err
    error_message = '%s, error is: %s' % (error_message, err)
    fatal_error(error_message, error_message)
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175


def ca_dirs_check(config, database_dir, certs_dir):
    """Check if mount's database and certs directories exist and if not, create directories (also create all intermediate
    directories if they don't exist)."""
    if not os.path.exists(database_dir):
        create_required_directory(config, database_dir)
    if not os.path.exists(certs_dir):
        create_required_directory(config, certs_dir)


def ca_supporting_files_check(index_path, index_attr_path, serial_path, rand_path):
    """Recreate all supporting openssl ca and req files if they're not present in their respective directories"""
    if not os.path.isfile(index_path):
        open(index_path, 'w').close()
    if not os.path.isfile(index_attr_path):
        with open(index_attr_path, 'w+') as f:
            f.write('unique_subject = no')
    if not os.path.isfile(serial_path):
        with open(serial_path, 'w+') as f:
            f.write('00')
    if not os.path.isfile(rand_path):
        open(rand_path, 'w').close()


def get_certificate_timestamp(current_time, **kwargs):
    updated_time = current_time + timedelta(**kwargs)
    return updated_time.strftime(CERT_DATETIME_FORMAT)


def get_utc_now():
    """
    Wrapped for patching purposes in unit tests
    """
    return datetime.utcnow()


Max Beckett's avatar
Max Beckett committed
1176
def assert_root():
Ian Patel's avatar
Ian Patel committed
1177
    if os.geteuid() != 0:
Max Beckett's avatar
Max Beckett committed
1178
1179
1180
1181
1182
        sys.stderr.write('only root can run mount.efs\n')
        sys.exit(1)


def read_config(config_file=CONFIG_FILE):
Yuan Gao's avatar
Yuan Gao committed
1183
1184
1185
1186
    try:
        p = ConfigParser.SafeConfigParser()
    except AttributeError:
        p = ConfigParser()
Max Beckett's avatar
Max Beckett committed
1187
1188
1189
1190
1191
    p.read(config_file)
    return p


def bootstrap_logging(config, log_dir=LOG_DIR):
Ian Patel's avatar
Ian Patel committed
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
    raw_level = config.get(CONFIG_SECTION, 'logging_level')
    levels = {
        'debug': logging.DEBUG,
        'info': logging.INFO,
        'warning': logging.WARNING,
        'error': logging.ERROR,
        'critical': logging.CRITICAL
    }
    level = levels.get(raw_level.lower())
    level_error = False

    if not level:
        # delay logging error about malformed log level until after logging is configured
        level_error = True
        level = logging.INFO

Max Beckett's avatar
Max Beckett committed
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
    max_bytes = config.getint(CONFIG_SECTION, 'logging_max_bytes')
    file_count = config.getint(CONFIG_SECTION, 'logging_file_count')

    handler = RotatingFileHandler(os.path.join(log_dir, LOG_FILE), maxBytes=max_bytes, backupCount=file_count)
    handler.setFormatter(logging.Formatter(fmt='%(asctime)s - %(levelname)s - %(message)s'))

    logger = logging.getLogger()
    logger.setLevel(level)
    logger.addHandler(handler)

Ian Patel's avatar
Ian Patel committed
1218
1219
1220
    if level_error:
        logging.error('Malformed logging level "%s", setting logging level to %s', raw_level, level)

Max Beckett's avatar
Max Beckett committed
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233

def get_dns_name(config, fs_id):
    def _validate_replacement_field_count(format_str, expected_ct):
        if format_str.count('{') != expected_ct or format_str.count('}') != expected_ct:
            raise ValueError('DNS name format has an incorrect number of replacement fields')

    dns_name_format = config.get(CONFIG_SECTION, 'dns_name_format')

    if '{fs_id}' not in dns_name_format:
        raise ValueError('DNS name format must include {fs_id}')

    format_args = {'fs_id': fs_id}

1234
1235
    expected_replacement_field_ct = 1

Max Beckett's avatar
Max Beckett committed
1236
    if '{region}' in dns_name_format:
1237
        expected_replacement_field_ct += 1
1238
        format_args['region'] = get_target_region(config)
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254

    if '{dns_name_suffix}' in dns_name_format:
        expected_replacement_field_ct += 1
        config_section = CONFIG_SECTION
        region = format_args.get('region')

        if region:
            region_specific_config_section = '%s.%s' % (CONFIG_SECTION, region)
            if config.has_section(region_specific_config_section):
                config_section = region_specific_config_section

        format_args['dns_name_suffix'] = config.get(config_section, 'dns_name_suffix')

        logging.debug("Using dns_name_suffix %s in config section [%s]", format_args.get('dns_name_suffix'), config_section)

    _validate_replacement_field_count(dns_name_format, expected_replacement_field_ct)
Max Beckett's avatar
Max Beckett committed
1255
1256
1257
1258
1259
1260
1261

    dns_name = dns_name_format.format(**format_args)

    try:
        socket.gethostbyname(dns_name)
    except socket.gaierror:
        fatal_error('Failed to resolve "%s" - check that your file system ID is correct.\nSee %s for more detail.'
Ian Patel's avatar
Ian Patel committed
1262
                    % (dns_name, 'https://docs.aws.amazon.com/console/efs/mount-dns-name'),
Max Beckett's avatar
Max Beckett committed
1263
1264
1265
1266
1267
                    'Failed to resolve "%s"' % dns_name)

    return dns_name


1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
def tls_paths_dictionary(mount_name, base_path=STATE_FILE_DIR):
    tls_dict = {
        'mount_dir': os.path.join(base_path, mount_name),
        # every mount will have its own ca mode assets due to lack of multi-threading support in openssl
        'database_dir': os.path.join(base_path, mount_name, 'database'),
        'certs_dir': os.path.join(base_path, mount_name, 'certs'),
        'index': os.path.join(base_path, mount_name, 'database/index.txt'),
        'index_attr': os.path.join(base_path, mount_name, 'database/index.txt.attr'),
        'serial': os.path.join(base_path, mount_name, 'database/serial'),
        'rand': os.path.join(base_path, mount_name, 'database/.rand')
    }

    return tls_dict


def get_public_key_sha1(public_key):
    # truncating public key to remove the header and footer '-----(BEGIN|END) PUBLIC KEY-----'
    with open(public_key, 'r') as f:
        lines = f.readlines()
        lines = lines[1:-1]

    key = ''.join(lines)
    key = bytearray(base64.b64decode(key))

    # Parse the public key to pull out the actual key material by looking for the key BIT STRING
    # Example:
    #     0:d=0  hl=4 l= 418 cons: SEQUENCE
    #     4:d=1  hl=2 l=  13 cons: SEQUENCE
    #     6:d=2  hl=2 l=   9 prim: OBJECT            :rsaEncryption
    #    17:d=2  hl=2 l=   0 prim: NULL
    #    19:d=1  hl=4 l= 399 prim: BIT STRING
    cmd = 'openssl asn1parse -inform PEM -in %s' % public_key
    output, err = subprocess_call(cmd, 'Unable to ASN1 parse public key file, %s, correctly' % public_key)

    key_line = ''
    for line in output.splitlines():
        if 'BIT STRING' in line.decode('utf-8'):
            key_line = line.decode('utf-8')

    if not key_line:
        err_msg = 'Public key file, %s, is incorrectly formatted' % public_key
        fatal_error(err_msg, err_msg)

    key_line = key_line.replace(' ', '')

    # DER encoding TLV (Tag, Length, Value)
    # - the first octet (byte) is the tag (type)
    # - the next octets are the length - "definite form"
    #   - the first octet always has the high order bit (8) set to 1
    #   - the remaining 127 bits are used to encode the number of octets that follow
    #   - the following octets encode, as big-endian, the length (which may be 0) as a number of octets
    # - the remaining octets are the "value" aka content
    #
    # For a BIT STRING, the first octet of the value is used to signify the number of unused bits that exist in the last
    # content byte. Note that this is explicitly excluded from the SubjectKeyIdentifier hash, per
    # https://tools.ietf.org/html/rfc5280#section-4.2.1.2
    #
    # Example:
    #   0382018f00...<subjectPublicKey>
    #   - 03 - BIT STRING tag
    #   - 82 - 2 length octets to follow (ignore high order bit)
    #   - 018f - length of 399
    #   - 00 - no unused bits in the last content byte
    offset = int(key_line.split(':')[0])
    key = key[offset:]

    num_length_octets = key[1] & 0b01111111

    # Exclude the tag (1), length (1 + num_length_octets), and number of unused bits (1)
    offset = 1 + 1 + num_length_octets + 1
    key = key[offset:]

    sha1 = hashlib.sha1()
    sha1.update(key)

    return sha1.hexdigest()


def create_canonical_request(public_key_hash, date, access_key, region, fs_id, session_token=None):
    """
    Create a Canonical Request - https://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
    """
    formatted_datetime = date.strftime(SIGV4_DATETIME_FORMAT)
    credential = quote_plus(access_key + '/' + get_credential_scope(date, region))

    request = HTTP_REQUEST_METHOD + '\n'
    request += CANONICAL_URI + '\n'
    request += create_canonical_query_string(public_key_hash, credential, formatted_datetime, session_token) + '\n'
    request += CANONICAL_HEADERS % fs_id + '\n'
    request += SIGNED_HEADERS + '\n'

    sha256 = hashlib.sha256()
    sha256.update(REQUEST_PAYLOAD.encode())
    request += sha256.hexdigest()

    return request


def create_canonical_query_string(public_key_hash, credential, formatted_datetime, session_token=None):
    canonical_query_params = {
        'Action': 'Connect',
        # Public key hash is included in canonical request to tie the signature to a specific key pair to avoid replay attacks
        'PublicKeyHash': quote_plus(public_key_hash),
        'X-Amz-Algorithm': ALGORITHM,
        'X-Amz-Credential': credential,
        'X-Amz-Date': quote_plus(formatted_datetime),
        'X-Amz-Expires': 86400,
        'X-Amz-SignedHeaders': SIGNED_HEADERS,
    }

    if session_token:
        canonical_query_params['X-Amz-Security-Token'] = quote_plus(session_token)

    # Cannot use urllib.urlencode because it replaces the %s's
    return '&'.join(['%s=%s' % (k, v) for k, v in sorted(canonical_query_params.items())])


def create_string_to_sign(canonical_request, date, region):
    """
    Create a String to Sign - https://docs.aws.amazon.com/general/latest/gr/sigv4-create-string-to-sign.html
    """
    string_to_sign = ALGORITHM + '\n'
    string_to_sign += date.strftime(SIGV4_DATETIME_FORMAT) + '\n'
    string_to_sign += get_credential_scope(date, region) + '\n'

    sha256 = hashlib.sha256()
    sha256.update(canonical_request.encode())
    string_to_sign += sha256.hexdigest()

    return string_to_sign


def calculate_signature(string_to_sign, date, secret_access_key, region):
    """
    Calculate the Signature - https://docs.aws.amazon.com/general/latest/gr/sigv4-calculate-signature.html
    """
    def _sign(key, msg):
        return hmac.new(key, msg.encode('utf-8'), hashlib.sha256)

    key_date = _sign(('AWS4' + secret_access_key).encode('utf-8'), date.strftime(DATE_ONLY_FORMAT)).digest()
    add_region = _sign(key_date, region).digest()
    add_service = _sign(add_region, SERVICE).digest()
    signing_key = _sign(add_service, 'aws4_request').digest()

    return _sign(signing_key, string_to_sign).hexdigest()


def get_credential_scope(date, region):
    return '/'.join([date.strftime(DATE_ONLY_FORMAT), region, SERVICE, AWS4_REQUEST])


1419
def match_device(config, device):
1420
    """Return the EFS id and the remote path to mount"""
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432

    try:
        remote, path = device.split(':', 1)
    except ValueError:
        remote = device
        path = '/'

    if FS_ID_RE.match(remote):
        return remote, path

    try:
        primary, secondaries, _ = socket.gethostbyname_ex(remote)
Yuan Gao's avatar
Yuan Gao committed
1433
        hostnames = list(filter(lambda e: e is not None, [primary] + secondaries))
1434
1435
1436
1437
1438
1439
1440
1441
1442
    except socket.gaierror:
        fatal_error(
            'Failed to resolve "%s" - check that the specified DNS name is a CNAME record resolving to a valid EFS DNS '
            'name' % remote,
            'Failed to resolve "%s"' % remote
        )

    if not hostnames:
        fatal_error(
1443
            'The specified domain name "%s" did not resolve to an EFS mount target' % remote
1444
1445
1446
1447
        )

    for hostname in hostnames:
        efs_fqdn_match = EFS_FQDN_RE.match(hostname)
1448

1449
1450
1451
        if efs_fqdn_match:
            fs_id = efs_fqdn_match.group('fs_id')
            expected_dns_name = get_dns_name(config, fs_id)