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forked from pool/mutt
mutt/mutt_oauth2.py-3.6

435 lines
18 KiB
Python

#!/usr/bin/python3
#
# Mutt OAuth2 token management script, version 2020-08-07
# Written against python 3.7.3, not tried with earlier python versions.
#
# Copyright (C) 2020 Alexander Perlis
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
'''Mutt OAuth2 token management'''
import sys
import json
import argparse
import urllib.parse
import urllib.request
import imaplib
import poplib
import smtplib
import base64
import secrets
import hashlib
import time
if sys.version_info < (3,7):
from datetime import date, timedelta, datetime, time
from backports.datetime_fromisoformat import MonkeyPatch
else:
from datetime import timedelta, datetime
from pathlib import Path
import socket
import http.server
import subprocess
if sys.version_info < (3,7):
from subprocess import PIPE
MonkeyPatch.patch_fromisoformat()
# The token file must be encrypted because it contains multi-use bearer tokens
# whose usage does not require additional verification. Specify whichever
# encryption and decryption pipes you prefer. They should read from standard
# input and write to standard output. The example values here invoke GPG,
# although won't work until an appropriate identity appears in the first line.
ENCRYPTION_PIPE = ['gpg', '--encrypt', '--recipient', 'YOUR_GPG_IDENTITY']
DECRYPTION_PIPE = ['gpg', '--decrypt']
registrations = {
'google': {
'authorize_endpoint': 'https://accounts.google.com/o/oauth2/auth',
'devicecode_endpoint': 'https://oauth2.googleapis.com/device/code',
'token_endpoint': 'https://accounts.google.com/o/oauth2/token',
'redirect_uri': 'urn:ietf:wg:oauth:2.0:oob',
'imap_endpoint': 'imap.gmail.com',
'pop_endpoint': 'pop.gmail.com',
'smtp_endpoint': 'smtp.gmail.com',
'sasl_method': 'OAUTHBEARER',
'scope': 'https://mail.google.com/',
'client_id': '',
'client_secret': '',
},
'microsoft': {
'authorize_endpoint': 'https://login.microsoftonline.com/common/oauth2/v2.0/authorize',
'devicecode_endpoint': 'https://login.microsoftonline.com/common/oauth2/v2.0/devicecode',
'token_endpoint': 'https://login.microsoftonline.com/common/oauth2/v2.0/token',
'redirect_uri': 'https://login.microsoftonline.com/common/oauth2/nativeclient',
'tenant': 'common',
'imap_endpoint': 'outlook.office365.com',
'pop_endpoint': 'outlook.office365.com',
'smtp_endpoint': 'smtp.office365.com',
'sasl_method': 'XOAUTH2',
'scope': ('offline_access https://outlook.office.com/IMAP.AccessAsUser.All '
'https://outlook.office.com/POP.AccessAsUser.All '
'https://outlook.office.com/SMTP.Send'),
'client_id': '',
'client_secret': '',
},
}
ap = argparse.ArgumentParser(epilog='''
This script obtains and prints a valid OAuth2 access token. State is maintained in an
encrypted TOKENFILE. Run with "--verbose --authorize" to get started or whenever all
tokens have expired, optionally with "--authflow" to override the default authorization
flow. To truly start over from scratch, first delete TOKENFILE. Use "--verbose --test"
to test the IMAP/POP/SMTP endpoints.
''')
ap.add_argument('-v', '--verbose', action='store_true', help='increase verbosity')
ap.add_argument('-d', '--debug', action='store_true', help='enable debug output')
ap.add_argument('tokenfile', help='persistent token storage')
ap.add_argument('-a', '--authorize', action='store_true', help='manually authorize new tokens')
ap.add_argument('--authflow', help='authcode | localhostauthcode | devicecode')
ap.add_argument('-t', '--test', action='store_true', help='test IMAP/POP/SMTP endpoints')
args = ap.parse_args()
token = {}
path = Path(args.tokenfile)
if path.exists():
if 0o777 & path.stat().st_mode != 0o600:
sys.exit('Token file has unsafe mode. Suggest deleting and starting over.')
try:
if sys.version_info < (3,7):
sub = subprocess.run(DECRYPTION_PIPE, check=True, input=path.read_bytes(),
stdout=PIPE, stderr=PIPE)
else:
sub = subprocess.run(DECRYPTION_PIPE, check=True, input=path.read_bytes(),
capture_output=True)
token = json.loads(sub.stdout)
except subprocess.CalledProcessError:
sys.exit('Difficulty decrypting token file. Is your decryption agent primed for '
'non-interactive usage, or an appropriate environment variable such as '
'GPG_TTY set to allow interactive agent usage from inside a pipe?')
def writetokenfile():
'''Writes global token dictionary into token file.'''
if not path.exists():
path.touch(mode=0o600)
if 0o777 & path.stat().st_mode != 0o600:
sys.exit('Token file has unsafe mode. Suggest deleting and starting over.')
if sys.version_info < (3,7):
sub2 = subprocess.run(ENCRYPTION_PIPE, check=True, input=json.dumps(token).encode(),
stdout=PIPE, stderr=PIPE)
else:
sub2 = subprocess.run(ENCRYPTION_PIPE, check=True, input=json.dumps(token).encode(),
capture_output=True)
path.write_bytes(sub2.stdout)
if args.debug:
print('Obtained from token file:', json.dumps(token))
if not token:
if not args.authorize:
sys.exit('You must run script with "--authorize" at least once.')
print('Available app and endpoint registrations:', *registrations)
token['registration'] = input('OAuth2 registration: ')
token['authflow'] = input('Preferred OAuth2 flow ("authcode" or "localhostauthcode" '
'or "devicecode"): ')
token['email'] = input('Account e-mail address: ')
token['access_token'] = ''
token['access_token_expiration'] = ''
token['refresh_token'] = ''
writetokenfile()
if token['registration'] not in registrations:
sys.exit(f'ERROR: Unknown registration "{token["registration"]}". Delete token file '
f'and start over.')
registration = registrations[token['registration']]
authflow = token['authflow']
if args.authflow:
authflow = args.authflow
baseparams = {'client_id': registration['client_id']}
# Microsoft uses 'tenant' but Google does not
if 'tenant' in registration:
baseparams['tenant'] = registration['tenant']
def access_token_valid():
'''Returns True when stored access token exists and is still valid at this time.'''
token_exp = token['access_token_expiration']
return token_exp and datetime.now() < datetime.fromisoformat(token_exp)
def update_tokens(r):
'''Takes a response dictionary, extracts tokens out of it, and updates token file.'''
token['access_token'] = r['access_token']
token['access_token_expiration'] = (datetime.now() +
timedelta(seconds=int(r['expires_in']))).isoformat()
if 'refresh_token' in r:
token['refresh_token'] = r['refresh_token']
writetokenfile()
if args.verbose:
print(f'NOTICE: Obtained new access token, expires {token["access_token_expiration"]}.')
if args.authorize:
p = baseparams.copy()
p['scope'] = registration['scope']
if authflow in ('authcode', 'localhostauthcode'):
verifier = secrets.token_urlsafe(90)
challenge = base64.urlsafe_b64encode(hashlib.sha256(verifier.encode()).digest())[:-1]
redirect_uri = registration['redirect_uri']
listen_port = 0
if authflow == 'localhostauthcode':
# Find an available port to listen on
s = socket.socket()
s.bind(('127.0.0.1', 0))
listen_port = s.getsockname()[1]
s.close()
redirect_uri = 'http://localhost:'+str(listen_port)+'/'
# Probably should edit the port number into the actual redirect URL.
p.update({'login_hint': token['email'],
'response_type': 'code',
'redirect_uri': redirect_uri,
'code_challenge': challenge,
'code_challenge_method': 'S256'})
print(registration["authorize_endpoint"] + '?' +
urllib.parse.urlencode(p, quote_via=urllib.parse.quote))
authcode = ''
if authflow == 'authcode':
authcode = input('Visit displayed URL to retrieve authorization code. Enter '
'code from server (might be in browser address bar): ')
else:
print('Visit displayed URL to authorize this application. Waiting...',
end='', flush=True)
class MyHandler(http.server.BaseHTTPRequestHandler):
'''Handles the browser query resulting from redirect to redirect_uri.'''
# pylint: disable=C0103
def do_HEAD(self):
'''Response to a HEAD requests.'''
self.send_response(200)
self.send_header('Content-type', 'text/html')
self.end_headers()
def do_GET(self):
'''For GET request, extract code parameter from URL.'''
# pylint: disable=W0603
global authcode
querystring = urllib.parse.urlparse(self.path).query
querydict = urllib.parse.parse_qs(querystring)
if 'code' in querydict:
authcode = querydict['code'][0]
self.do_HEAD()
self.wfile.write(b'<html><head><title>Authorizaton result</title></head>')
self.wfile.write(b'<body><p>Authorization redirect completed. You may '
b'close this window.</p></body></html>')
with http.server.HTTPServer(('127.0.0.1', listen_port), MyHandler) as httpd:
try:
httpd.handle_request()
except KeyboardInterrupt:
pass
if not authcode:
sys.exit('Did not obtain an authcode.')
for k in 'response_type', 'login_hint', 'code_challenge', 'code_challenge_method':
del p[k]
p.update({'grant_type': 'authorization_code',
'code': authcode,
'client_secret': registration['client_secret'],
'code_verifier': verifier})
try:
response = urllib.request.urlopen(registration['token_endpoint'],
urllib.parse.urlencode(p).encode())
except urllib.error.HTTPError as err:
print(err.code, err.reason)
response = err
response = response.read()
if args.debug:
print(response)
response = json.loads(response)
if 'error' in response:
print(response['error'])
if 'error_description' in response:
print(response['error_description'])
sys.exit(1)
elif authflow == 'devicecode':
try:
response = urllib.request.urlopen(registration['devicecode_endpoint'],
urllib.parse.urlencode(p).encode())
except urllib.error.HTTPError as err:
print(err.code, err.reason)
response = err
response = response.read()
if args.debug:
print(response)
response = json.loads(response)
if 'error' in response:
print(response['error'])
if 'error_description' in response:
print(response['error_description'])
sys.exit(1)
print(response['message'])
del p['scope']
p.update({'grant_type': 'urn:ietf:params:oauth:grant-type:device_code',
'client_secret': registration['client_secret'],
'device_code': response['device_code']})
interval = int(response['interval'])
print('Polling...', end='', flush=True)
while True:
time.sleep(interval)
print('.', end='', flush=True)
try:
response = urllib.request.urlopen(registration['token_endpoint'],
urllib.parse.urlencode(p).encode())
except urllib.error.HTTPError as err:
# Not actually always an error, might just mean "keep trying..."
response = err
response = response.read()
if args.debug:
print(response)
response = json.loads(response)
if 'error' not in response:
break
if response['error'] == 'authorization_declined':
print(' user declined authorization.')
sys.exit(1)
if response['error'] == 'expired_token':
print(' too much time has elapsed.')
sys.exit(1)
if response['error'] != 'authorization_pending':
print(response['error'])
if 'error_description' in response:
print(response['error_description'])
sys.exit(1)
print()
else:
sys.exit(f'ERROR: Unknown OAuth2 flow "{token["authflow"]}. Delete token file and '
f'start over.')
update_tokens(response)
if not access_token_valid():
if args.verbose:
print('NOTICE: Invalid or expired access token; using refresh token '
'to obtain new access token.')
if not token['refresh_token']:
sys.exit('ERROR: No refresh token. Run script with "--authorize".')
p = baseparams.copy()
p.update({'client_secret': registration['client_secret'],
'refresh_token': token['refresh_token'],
'grant_type': 'refresh_token'})
try:
response = urllib.request.urlopen(registration['token_endpoint'],
urllib.parse.urlencode(p).encode())
except urllib.error.HTTPError as err:
print(err.code, err.reason)
response = err
response = response.read()
if args.debug:
print(response)
response = json.loads(response)
if 'error' in response:
print(response['error'])
if 'error_description' in response:
print(response['error_description'])
print('Perhaps refresh token invalid. Try running once with "--authorize"')
sys.exit(1)
update_tokens(response)
if not access_token_valid():
sys.exit('ERROR: No valid access token. This should not be able to happen.')
if args.verbose:
print('Access Token: ', end='')
print(token['access_token'])
def build_sasl_string(user, host, port, bearer_token):
'''Build appropriate SASL string, which depends on cloud server's supported SASL method.'''
if registration['sasl_method'] == 'OAUTHBEARER':
return f'n,a={user},\1host={host}\1port={port}\1auth=Bearer {bearer_token}\1\1'
if registration['sasl_method'] == 'XOAUTH2':
return f'user={user}\1auth=Bearer {bearer_token}\1\1'
sys.exit(f'Unknown SASL method {registration["sasl_method"]}.')
if args.test:
errors = False
imap_conn = imaplib.IMAP4_SSL(registration['imap_endpoint'])
sasl_string = build_sasl_string(token['email'], registration['imap_endpoint'], 993,
token['access_token'])
if args.debug:
imap_conn.debug = 4
try:
imap_conn.authenticate(registration['sasl_method'], lambda _: sasl_string.encode())
# Microsoft has a bug wherein a mismatch between username and token can still report a
# successful login... (Try a consumer login with the token from a work/school account.)
# Fortunately subsequent commands fail with an error. Thus we follow AUTH with another
# IMAP command before reporting success.
imap_conn.list()
if args.verbose:
print('IMAP authentication succeeded')
except imaplib.IMAP4.error as e:
print('IMAP authentication FAILED (does your account allow IMAP?):', e)
errors = True
pop_conn = poplib.POP3_SSL(registration['pop_endpoint'])
sasl_string = build_sasl_string(token['email'], registration['pop_endpoint'], 995,
token['access_token'])
if args.debug:
pop_conn.set_debuglevel(2)
try:
# poplib doesn't have an auth command taking an authenticator object
# Microsoft requires a two-line SASL for POP
# pylint: disable=W0212
pop_conn._shortcmd('AUTH ' + registration['sasl_method'])
pop_conn._shortcmd(base64.standard_b64encode(sasl_string.encode()).decode())
if args.verbose:
print('POP authentication succeeded')
except poplib.error_proto as e:
print('POP authentication FAILED (does your account allow POP?):', e.args[0].decode())
errors = True
# SMTP_SSL would be simpler but Microsoft does not answer on port 465.
smtp_conn = smtplib.SMTP(registration['smtp_endpoint'], 587)
sasl_string = build_sasl_string(token['email'], registration['smtp_endpoint'], 587,
token['access_token'])
smtp_conn.ehlo('test')
smtp_conn.starttls()
smtp_conn.ehlo('test')
if args.debug:
smtp_conn.set_debuglevel(2)
try:
smtp_conn.auth(registration['sasl_method'], lambda _=None: sasl_string)
if args.verbose:
print('SMTP authentication succeeded')
except smtplib.SMTPAuthenticationError as e:
print('SMTP authentication FAILED:', e)
errors = True
if errors:
sys.exit(1)