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| -rwxr-xr-x | bin/mutt_oauth2.py | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/bin/mutt_oauth2.py b/bin/mutt_oauth2.py new file mode 100755 index 0000000..f67364e --- /dev/null +++ b/bin/mutt_oauth2.py @@ -0,0 +1,419 @@ +#!/usr/bin/env 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 +from datetime import timedelta, datetime +from pathlib import Path +import socket +import http.server +import subprocess + +# 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 = ['cat'] +DECRYPTION_PIPE = ['cat'] + +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': '08162f7c-0fd2-4200-a84a-f25a4db0b584', + 'client_secret': 'TxRBilcHdC6WGBee]fs?QR:SJ8nI[g82', + }, +} + +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: + 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.') + 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) |