Update checked in version of gsutil to version 4.6

gslib/commands/signurl.py

+# -*- coding: utf-8 -*-
+# Copyright 2014 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Implementation of Url Signing workflow.
+
+see: https://developers.google.com/storage/docs/accesscontrol#Signed-URLs)
+"""
+
+from __future__ import absolute_import
+
+import base64
+import calendar
+from datetime import datetime
+from datetime import timedelta
+import getpass
+import re
+import time
+import urllib
+
+import httplib2
+
+from gslib.command import Command
+from gslib.cs_api_map import ApiSelector
+from gslib.exception import CommandException
+from gslib.storage_url import ContainsWildcard
+from gslib.storage_url import StorageUrlFromString
+from gslib.util import GetNewHttp
+from gslib.util import NO_MAX
+
+try:
+  # Check for openssl.
+  # pylint: disable=C6204
+  from OpenSSL.crypto import load_pkcs12
+  from OpenSSL.crypto import sign
+  HAVE_OPENSSL = True
+except ImportError:
+  load_pkcs12 = None
+  sign = None
+  HAVE_OPENSSL = False
+
+_DETAILED_HELP_TEXT = ("""
+<B>SYNOPSIS</B>
+  gsutil signurl pkcs12-file url...
+
+
+<B>DESCRIPTION</B>
+  The signurl command will generate signed urls that can be used to access
+  the specified objects without authentication for a specific period of time.
+
+  Please see the `Signed URLs documentation
+  https://developers.google.com/storage/docs/accesscontrol#Signed-URLs` for
+  background about signed URLs.
+
+  Multiple gs:// urls may be provided and may contain wildcards.  A signed url
+  will be produced for each provided url, authorized
+  for the specified HTTP method and valid for the given duration.
+
+  Note: Unlike the gsutil ls command, the signurl command does not support
+  operations on sub-directories. For example, if you run the command:
+
+    gsutil signurl <private-key-file> gs://some-bucket/some-object/
+
+  The signurl command uses the private key for a  service account (the
+  '<private-key-file>' argument) to generate the cryptographic
+  signature for the generated URL.  The private key file must be in PKCS12
+  format. The signurl command will prompt for the passphrase used to protect
+  the private key file (default 'notasecret').  For more information
+  regarding generating a private key for use with the signurl command please
+  see the `Authentication documentation.
+  https://developers.google.com/storage/docs/authentication#generating-a-private-key`
+
+  gsutil will look up information about the object "some-object/" (with a
+  trailing slash) inside bucket "some-bucket", as opposed to operating on
+  objects nested under gs://some-bucket/some-object. Unless you actually
+  have an object with that name, the operation will fail.
+
+<B>OPTIONS</B>
+  -m          Specifies the HTTP method to be authorized for use
+              with the signed url, default is GET.
+
+  -d          Specifies the duration that the signed url should be valid
+              for, default duration is 1 hour.
+
+              Times may be specified with no suffix (default hours), or
+              with s = seconds, m = minutes, h = hours, d = days.
+
+              This option may be specified multiple times, in which case
+              the duration the link remains valid is the sum of all the
+              duration options.
+
+  -c          Specifies the content type for which the signed url is
+              valid for.
+
+  -p          Specify the keystore password instead of prompting.
+
+<B>USAGE</B>
+
+  Create a signed url for downloading an object valid for 10 minutes:
+
+    gsutil signurl <private-key-file> -d 10m gs://<bucket>/<object>
+
+  Create a signed url for uploading a plain text file via HTTP PUT:
+
+    gsutil signurl <private-key-file> -m PUT -d 1h -c text/plain gs://<bucket>/<obj>
+
+  To construct a signed URL that allows anyone in possession of
+  the URL to PUT to the specified bucket for one day, creating
+  any object of Content-Type image/jpg, run:
+
+    gsutil signurl <private-key-file> -m PUT -d 1d -c image/jpg gs://<bucket>/<obj>
+
+
+""")
+
+
+def _DurationToTimeDelta(duration):
+  r"""Parses the given duration and returns an equivalent timedelta."""
+
+  match = re.match(r'^(\d+)([dDhHmMsS])?$', duration)
+  if not match:
+    raise CommandException('Unable to parse duration string')
+
+  duration, modifier = match.groups('h')
+  duration = int(duration)
+  modifier = modifier.lower()
+
+  if modifier == 'd':
+    ret = timedelta(days=duration)
+  elif modifier == 'h':
+    ret = timedelta(hours=duration)
+  elif modifier == 'm':
+    ret = timedelta(minutes=duration)
+  elif modifier == 's':
+    ret = timedelta(seconds=duration)
+
+  return ret
+
+
+def _GenSignedUrl(key, client_id, method, md5,
+                  content_type, expiration, gcs_path):
+  """Construct a string to sign with the provided key and returns \
+  the complete url."""
+
+  tosign = ('{0}\n{1}\n{2}\n{3}\n/{4}'
+            .format(method, md5, content_type,
+                    expiration, gcs_path))
+  signature = base64.b64encode(sign(key, tosign, 'RSA-SHA256'))
+
+  final_url = ('https://storage.googleapis.com/{0}?'
+               'GoogleAccessId={1}&Expires={2}&Signature={3}'
+               .format(gcs_path, client_id, expiration,
+                       urllib.quote_plus(str(signature))))
+
+  return final_url
+
+
+def _ReadKeystore(ks_contents, passwd):
+  ks = load_pkcs12(ks_contents, passwd)
+  client_id = (ks.get_certificate()
+               .get_subject()
+               .CN.replace('.apps.googleusercontent.com',
+                           '@developer.gserviceaccount.com'))
+
+  return ks, client_id
+
+
+class UrlSignCommand(Command):
+  """Implementation of gsutil url_sign command."""
+
+  # Command specification. See base class for documentation.
+  command_spec = Command.CreateCommandSpec(
+      'signurl',
+      command_name_aliases=['signedurl', 'queryauth'],
+      min_args=2,
+      max_args=NO_MAX,
+      supported_sub_args='m:d:c:p:',
+      file_url_ok=False,
+      provider_url_ok=False,
+      urls_start_arg=1,
+      gs_api_support=[ApiSelector.XML, ApiSelector.JSON],
+      gs_default_api=ApiSelector.JSON,
+  )
+  # Help specification. See help_provider.py for documentation.
+  help_spec = Command.HelpSpec(
+      help_name='signurl',
+      help_name_aliases=['signedurl', 'queryauth'],
+      help_type='command_help',
+      help_one_line_summary='Create a signed url',
+      help_text=_DETAILED_HELP_TEXT,
+      subcommand_help_text={},
+  )
+
+  def _ParseSubOpts(self):
+    # Default argument values
+    delta = None
+    method = 'GET'
+    content_type = ''
+    passwd = None
+
+    for o, v in self.sub_opts:
+      if o == '-d':
+        if delta is not None:
+          delta += _DurationToTimeDelta(v)
+        else:
+          delta = _DurationToTimeDelta(v)
+      elif o == '-m':
+        method = v
+      elif o == '-c':
+        content_type = v
+      elif o == '-p':
+        passwd = v
+
+    if delta is None:
+      delta = timedelta(hours=1)
+
+    expiration = calendar.timegm((datetime.utcnow() + delta).utctimetuple())
+    if method not in ['GET', 'PUT', 'DELETE', 'HEAD']:
+      raise CommandException('HTTP method must be one of [GET|HEAD|PUT|DELETE]')
+
+    return method, expiration, content_type, passwd
+
+  def _CheckClientCanRead(self, key, client_id, gcs_path):
+    """Performs a head request against a signed url to check for read access."""
+
+    signed_url = _GenSignedUrl(key, client_id,
+                               'HEAD', '', '',
+                               int(time.time()) + 10,
+                               gcs_path)
+    h = GetNewHttp()
+    try:
+      response, _ = h.request(signed_url, 'HEAD')
+
+      return response.status == 200
+    except httplib2.HttpLib2Error as e:
+      raise CommandException('Unexpected error while querying'
+                             'object readability ({0})'
+                             .format(e.message))
+
+  def _EnumerateStorageUrls(self, in_urls):
+    ret = []
+
+    for url_str in in_urls:
+      if ContainsWildcard(url_str):
+        ret.extend([blr.storage_url for blr in self.WildcardIterator(url_str)])
+      else:
+        ret.append(StorageUrlFromString(url_str))
+
+    return ret
+
+  def RunCommand(self):
+    """Command entry point for signurl command."""
+    if not HAVE_OPENSSL:
+      raise CommandException(
+          'The signurl command requires the pyopenssl library (try pip '
+          'install pyopenssl or easy_install pyopenssl)')
+
+    method, expiration, content_type, passwd = self._ParseSubOpts()
+    storage_urls = self._EnumerateStorageUrls(self.args[1:])
+
+    if not passwd:
+      passwd = getpass.getpass('Keystore password:')
+
+    ks, client_id = _ReadKeystore(open(self.args[0], 'rb').read(), passwd)
+
+    print 'URL\tHTTP Method\tExpiration\tSigned URL'
+    for url in storage_urls:
+      if url.scheme != 'gs':
+        raise CommandException('Can only create signed urls from gs:// urls')
+      if url.IsBucket():
+        gcs_path = url.bucket_name
+      else:
+        gcs_path = '{0}/{1}'.format(url.bucket_name, url.object_name)
+
+      final_url = _GenSignedUrl(ks.get_privatekey(), client_id,
+                                method, '', content_type, expiration,
+                                gcs_path)
+
+      expiration_dt = datetime.fromtimestamp(expiration)
+
+      print '{0}\t{1}\t{2}\t{3}'.format(url, method,
+                                        (expiration_dt
+                                         .strftime('%Y-%m-%d %H:%M:%S')),
+                                        final_url)
+      if  (method != 'PUT' and
+           not self._CheckClientCanRead(ks.get_privatekey(),
+                                        client_id,
+                                        gcs_path)):
+        self.logger.warn(
+            '%s does not have permissions on %s, using this link will likely '
+            'result in a 403 error until at least READ permissions are granted',
+            client_id, url)
+
+    return 0