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#!/usr/bin/env python3
# noinspection PyUnresolvedReferences
import falcon
import os
import logging
import json
import sqlalchemy as sa
import patatt
import smtplib
import email
import email.header
import email.policy
import re
from configparser import ConfigParser, ExtendedInterpolation
from string import Template
from email import utils
from typing import Tuple, Union
from email import charset
charset.add_charset('utf-8', None)
emlpolicy = email.policy.EmailPolicy(utf8=True, cte_type='8bit', max_line_length=None)
DB_VERSION = 1
# We'll make this configurable later
TPT_VERIFY_SUBJECT = 'Web endpoint verification for ${identity}'
TPT_VERIFY_BODY = '''Dear ${name}:
Somebody, probably you, initiated a web endpoint verification routine
for patch submissions at: ${myurl}
If you have no idea what is going on, please ignore this message.
Otherwise, please follow instructions provided by your tool and paste
the following string:
${challenge}
Happy patching!
--
Deet-doot-dot, I'm a bot
https://korg.docs.kernel.org/
'''
DEFAULT_CFG = '''
[main]
myname = Web Endpoint
myurl = http://localhost:8000/_b4_submit
dburl = sqlite:///:memory:
mydomains = kernel.org, linux.dev
dryrun = false
[sendemail]
smtpserver = localhost
from = devnull@kernel.org
[public-inbox]
repo =
listid = patches.feeds.kernel.org
'''
logger = logging.getLogger('b4-send-receive')
# noinspection PyBroadException, PyMethodMayBeStatic
class SendReceiveListener(object):
def __init__(self, _engine, _config):
self._engine = _engine
self._config = _config
# You shouldn't use this in production
if self._engine.driver == 'pysqlite':
self._init_sa_db()
def _init_sa_db(self):
logger.info('Creating tables')
conn = self._engine.connect()
md = sa.MetaData()
meta = sa.Table('meta', md,
sa.Column('version', sa.Integer())
)
auth = sa.Table('auth', md,
sa.Column('auth_id', sa.Integer(), primary_key=True),
sa.Column('created', sa.DateTime(), nullable=False, server_default=sa.sql.func.now()),
sa.Column('identity', sa.Text(), nullable=False),
sa.Column('selector', sa.Text(), nullable=False),
sa.Column('pubkey', sa.Text(), nullable=False),
sa.Column('challenge', sa.Text(), nullable=True),
sa.Column('verified', sa.Integer(), nullable=False),
)
sa.Index('idx_identity_selector', auth.c.identity, auth.c.selector, unique=True)
md.create_all(self._engine)
q = sa.insert(meta).values(version=DB_VERSION)
conn.execute(q)
def on_get(self, req, resp): # noqa
resp.status = falcon.HTTP_200
resp.content_type = falcon.MEDIA_TEXT
resp.text = "We don't serve GETs here\n"
def send_error(self, resp, message: str):
resp.status = falcon.HTTP_500
resp.text = json.dumps({'result': 'error', 'message': message})
def send_success(self, resp, message: str):
resp.status = falcon.HTTP_200
resp.text = json.dumps({'result': 'success', 'message': message})
def get_smtp(self) -> Tuple[Union[smtplib.SMTP, smtplib.SMTP_SSL, None], Tuple[str, str]]:
sconfig = self._config['sendemail']
server = sconfig.get('smtpserver', 'localhost')
port = sconfig.get('smtpserverport', 0)
encryption = sconfig.get('smtpencryption')
logger.debug('Connecting to %s:%s', server, port)
# We only authenticate if we have encryption
if encryption:
if encryption in ('tls', 'starttls'):
# We do startssl
smtp = smtplib.SMTP(server, port)
# Introduce ourselves
smtp.ehlo()
# Start encryption
smtp.starttls()
# Introduce ourselves again to get new criteria
smtp.ehlo()
elif encryption in ('ssl', 'smtps'):
# We do TLS from the get-go
smtp = smtplib.SMTP_SSL(server, port)
else:
raise smtplib.SMTPException('Unclear what to do with smtpencryption=%s' % encryption)
# If we got to this point, we should do authentication.
auser = sconfig.get('smtpuser')
apass = sconfig.get('smtppass')
if auser and apass:
# Let any exceptions bubble up
smtp.login(auser, apass)
else:
# We assume you know what you're doing if you don't need encryption
smtp = smtplib.SMTP(server, port)
frompair = utils.getaddresses([sconfig.get('from')])[0]
return smtp, frompair
def auth_new(self, jdata, resp):
# Is it already authorized?
conn = self._engine.connect()
md = sa.MetaData()
identity = jdata.get('identity')
selector = jdata.get('selector')
pubkey = jdata.get('pubkey')
t_auth = sa.Table('auth', md, autoload=True, autoload_with=self._engine)
q = sa.select([t_auth.c.auth_id]).where(t_auth.c.identity == identity, t_auth.c.selector == selector,
t_auth.c.verified == 1)
rp = conn.execute(q)
if len(rp.fetchall()):
self.send_error(resp, message='i=%s;s=%s is already authorized' % (identity, selector))
return
# delete any existing challenges for this and create a new one
q = sa.delete(t_auth).where(t_auth.c.identity == identity, t_auth.c.selector == selector,
t_auth.c.verified == 0)
conn.execute(q)
# create new challenge
import uuid
cstr = str(uuid.uuid4())
q = sa.insert(t_auth).values(identity=identity, selector=selector, pubkey=pubkey, challenge=cstr,
verified=0)
conn.execute(q)
logger.info('Challenge: %s', cstr)
smtp, frompair = self.get_smtp()
cmsg = email.message.EmailMessage()
fromname, fromaddr = frompair
if len(fromname):
cmsg.add_header('From', f'{fromname} <{fromaddr}>')
else:
cmsg.add_header('From', fromaddr)
subject = Template(TPT_VERIFY_SUBJECT).safe_substitute({'identity': jdata.get('identity')})
cmsg.add_header('Subject', subject)
name = jdata.get('name', 'Anonymous Llama')
cmsg.add_header('To', f'{name} <{identity}>')
cmsg.add_header('Message-Id', utils.make_msgid('b4-verify'))
vals = {
'name': name,
'myurl': self._config['main'].get('myurl'),
'challenge': cstr,
}
body = Template(TPT_VERIFY_BODY).safe_substitute(vals)
cmsg.set_payload(body, charset='utf-8')
bdata = cmsg.as_bytes(policy=emlpolicy)
destaddrs = [identity]
alwaysbcc = self._config['main'].get('alwayscc')
if alwaysbcc:
destaddrs += [x[1] for x in utils.getaddresses(alwaysbcc)]
smtp.sendmail(fromaddr, [identity], bdata)
self.send_success(resp, message=f'Challenge generated and sent to {identity}')
def validate_message(self, conn, t_auth, bdata, verified=1):
# Returns auth_id of the matching record
pm = patatt.PatattMessage(bdata)
if not pm.signed:
return None
auth_id = identity = pubkey = None
for ds in pm.get_sigs():
selector = 'default'
identity = ''
i = ds.get_field('i')
if i:
identity = i.decode()
s = ds.get_field('s')
if s:
selector = s.decode()
logger.debug('i=%s; s=%s', identity, selector)
q = sa.select([t_auth.c.auth_id, t_auth.c.pubkey]).where(t_auth.c.identity == identity,
t_auth.c.selector == selector,
t_auth.c.verified == verified)
rp = conn.execute(q)
res = rp.fetchall()
if res:
auth_id, pubkey = res[0]
break
logger.debug('auth_id=%s', auth_id)
if not auth_id:
return None
try:
pm.validate(identity, pubkey.encode())
except Exception as ex:
logger.debug('Validation failed: %s', ex)
return None
return auth_id
def auth_verify(self, jdata, resp):
msg = jdata.get('msg')
if msg.find('\nverify:') < 0:
self.send_error(resp, message='Invalid verification message')
return
conn = self._engine.connect()
md = sa.MetaData()
t_auth = sa.Table('auth', md, autoload=True, autoload_with=self._engine)
bdata = msg.encode()
auth_id = self.validate_message(conn, t_auth, bdata, verified=0)
if auth_id is None:
self.send_error(resp, message='Signature validation failed')
return
# Now compare the challenge to what we received
q = sa.select([t_auth.c.challenge]).where(t_auth.c.auth_id == auth_id)
rp = conn.execute(q)
res = rp.fetchall()
challenge = res[0][0]
if msg.find(f'\nverify:{challenge}') < 0:
self.send_error(resp, message='Invalid verification string')
return
q = sa.update(t_auth).where(t_auth.c.auth_id == auth_id).values(challenge=None, verified=1)
conn.execute(q)
self.send_success(resp, message='Challenge verified')
def auth_delete(self, jdata, resp):
msg = jdata.get('msg')
if msg.find('\nauth-delete') < 0:
self.send_error(resp, message='Invalid key delete message')
return
conn = self._engine.connect()
md = sa.MetaData()
t_auth = sa.Table('auth', md, autoload=True, autoload_with=self._engine)
bdata = msg.encode()
auth_id = self.validate_message(conn, t_auth, bdata)
if auth_id is None:
self.send_error(resp, message='Signature validation failed')
return
q = sa.delete(t_auth).where(t_auth.c.auth_id == auth_id)
conn.execute(q)
self.send_success(resp, message='Authentication deleted')
def clean_header(self, hdrval):
if hdrval is None:
return ''
decoded = ''
for hstr, hcs in email.header.decode_header(hdrval):
if hcs is None:
hcs = 'utf-8'
try:
decoded += hstr.decode(hcs, errors='replace')
except LookupError:
# Try as utf-u
decoded += hstr.decode('utf-8', errors='replace')
except (UnicodeDecodeError, AttributeError):
decoded += hstr
new_hdrval = re.sub(r'\n?\s+', ' ', decoded)
return new_hdrval.strip()
def receive(self, jdata, resp):
servicename = self._config['main'].get('myname')
if not servicename:
servicename = 'Web Endpoint'
umsgs = jdata.get('messages')
if not umsgs:
self.send_error(resp, message='Missing the messages array')
return
msgs = list()
conn = self._engine.connect()
md = sa.MetaData()
t_auth = sa.Table('auth', md, autoload=True, autoload_with=self._engine)
# First, validate all signatures
at = 0
for umsg in umsgs:
at += 1
auth_id = self.validate_message(conn, t_auth, umsg.encode())
if auth_id is None:
self.send_error(resp, message=f'Signature validation failed for message {at}')
return
msg = email.message_from_string(umsg)
msg.add_header('X-Endpoint-Received', f'by {servicename} with auth_id={auth_id}')
msgs.append(msg)
# All signatures verified. Prepare messages for sending.
cfgdomains = self._config['main'].get('mydomains')
if cfgdomains is not None:
mydomains = [x.strip() for x in cfgdomains.split(',')]
else:
mydomains = list()
smtp, frompair = self.get_smtp()
for msg in msgs:
# TODO: public-inbox writing at this point
subject = self.clean_header(msg.get('Subject'))
origfrom = self.clean_header(msg.get('From'))
origpair = utils.getaddresses([origfrom])[0]
origaddr = origpair[1]
# Does it match one of our domains
mydomain = False
for _domain in mydomains:
if origaddr.endswith(f'@{_domain}'):
mydomain = True
break
if mydomain:
fromaddr = origaddr
else:
fromaddr = frompair[1]
# We can't just send this as-is due to DMARC policies. Therefore, we set
# Reply-To and X-Original-From.
origname = origpair[0]
if not origname:
origname = origpair[1]
msg.replace_header('From', f'{origname} via {servicename} <{fromaddr}>')
if msg.get('X-Original-From'):
msg.replace_header('X-Original-From', origfrom)
else:
msg.add_header('X-Original-From', origfrom)
if msg.get('Reply-To'):
msg.replace_header('Reply-To', f'<{origpair[1]}>')
else:
msg.add_header('Reply-To', f'<{origpair[1]}>')
# Does the subject start with [PATCH?
if subject.startswith('[PATCH '):
body = msg.get_payload()
# Parse it as a message and see if we get a From: header
cmsg = email.message_from_string(body)
if cmsg.get('From') is None:
cmsg.add_header('From', origfrom)
msg.set_payload(cmsg.as_string(policy=emlpolicy, maxheaderlen=0), charset='utf-8')
alldests = utils.getaddresses([str(x) for x in msg.get_all('to', [])])
alldests += utils.getaddresses([str(x) for x in msg.get_all('cc', [])])
alwaysbcc = self._config['main'].get('alwaysbcc')
if alwaysbcc:
alldests += utils.getaddresses([alwaysbcc])
destaddrs = {x[1] for x in alldests}
bdata = msg.as_string(policy=emlpolicy).encode()
if not self._config['main'].getboolean('dryrun'):
smtp.sendmail(fromaddr, list(destaddrs), bdata)
logger.info('Sent %s', subject)
else:
logger.info('---DRYRUN MSG START---')
logger.info(msg)
logger.info('---DRYRUN MSG END---')
self.send_success(resp, message=f'Sent {len(msgs)} messages')
def on_post(self, req, resp):
if not req.content_length:
resp.status = falcon.HTTP_500
resp.content_type = falcon.MEDIA_TEXT
resp.text = 'Payload required\n'
return
raw = req.bounded_stream.read()
try:
jdata = json.loads(raw)
except:
resp.status = falcon.HTTP_500
resp.content_type = falcon.MEDIA_TEXT
resp.text = 'Failed to parse the request\n'
return
action = jdata.get('action')
if action == 'auth-new':
self.auth_new(jdata, resp)
return
if action == 'auth-verify':
self.auth_verify(jdata, resp)
return
if action == 'auth-delete':
self.auth_delete(jdata, resp)
return
if action == 'receive':
self.receive(jdata, resp)
return
resp.status = falcon.HTTP_500
resp.content_type = falcon.MEDIA_TEXT
resp.text = 'Unknown action: %s\n' % action
parser = ConfigParser(interpolation=ExtendedInterpolation())
cfgfile = os.getenv('CONFIG')
if cfgfile:
parser.read(cfgfile)
else:
parser.read_string(DEFAULT_CFG)
gpgbin = parser['main'].get('gpgbin')
if gpgbin:
patatt.GPGBIN = gpgbin
dburl = parser['main'].get('dburl')
engine = sa.create_engine(dburl)
srl = SendReceiveListener(engine, parser)
app = falcon.App()
mp = os.getenv('MOUNTPOINT', '/_b4_submit')
app.add_route(mp, srl)
if __name__ == '__main__':
from wsgiref.simple_server import make_server
logger.setLevel(logging.DEBUG)
ch = logging.StreamHandler()
formatter = logging.Formatter('%(message)s')
ch.setFormatter(formatter)
ch.setLevel(logging.DEBUG)
logger.addHandler(ch)
with make_server('', 8000, app) as httpd:
logger.info('Serving on port 8000...')
# Serve until process is killed
httpd.serve_forever()
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