ejabberd-auth-mastodon/auth-mastodon.py

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#!/usr/bin/env python3
import atexit
import logging
import struct
import sys
import time
import bcrypt
import psycopg2
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# Database connection details. The credentials here need access to the Mastodon database, which "ejabberd" is unlikely
# to have on your system by default. You shoud grant SELECT privileges to ejabberd on the "accounts" and "users" tables,
# to play it safe, or include the Mastodon DB user credentials here (don't).
db_host = "localhost"
db_port = 5432
db_user = "ejabberd"
db_pass = ""
db_name = "mastodon"
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# This is the query that pulls the password hash for the given user. Mastodon doesn't store the domain for local accounts in
# the database, so we ignore the host component and try to match username where the domain is NULL.
db_query_getpass = """
SELECT users.encrypted_password AS password
FROM accounts
INNER JOIN users
ON accounts.id = users.account_id
WHERE
lower(accounts.username) = %(user)s
AND accounts.domain IS NULL
"""
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########################################################################
# Setup
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########################################################################
sys.stderr = open('/var/log/ejabberd/extauth_err.log', 'a')
logging.basicConfig(
level=logging.INFO,
format='%(asctime)s %(levelname)s %(message)s',
filename='/var/log/ejabberd/extauth.log',
filemode='a',
)
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try:
# Connect to the DB, set autocommit and readonly otherwise postgresql seems to have a
# tendency to keep things "idle in transaction" and table locks eventually grind
# Mastodon to a halt. We don't make any changes anyway.
database = psycopg2.connect(host=db_host, user=db_user, password=db_pass, database=db_name, port=db_port)
database.set_session(readonly=True, autocommit=True)
logging.debug(database.get_dsn_parameters())
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except:
logging.error("Unable to initialize database, check settings!")
time.sleep(10)
sys.exit(1)
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@atexit.register
def close_db():
cursor.close()
database.close()
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logging.info('auth-mastodon script started, waiting for ejabberd requests')
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class EjabberdInputError(Exception):
def __init__(self, value):
self.value = value
def __str__(self):
return repr(self.value)
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########################################################################
# Declarations
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########################################################################
def ejabberd_in():
logging.debug("trying to read 2 bytes from ejabberd:")
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input_length = sys.stdin.buffer.read(2)
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if len(input_length) is not 2:
logging.debug("ejabberd sent us wrong things!")
raise EjabberdInputError('Wrong input from ejabberd!')
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logging.debug('got 2 bytes via stdin: %s' % input_length)
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(size,) = struct.unpack('>h', input_length)
logging.debug('size of data: %i' % size)
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income = sys.stdin.read(size)
logging.debug("incoming data: %s" % income)
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return income
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def ejabberd_out(bool):
logging.debug("Ejabberd gets: %s" % bool)
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token = genanswer(bool)
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logging.debug("sent bytes: %#x %#x %#x %#x" % (token[0], token[1], token[2], token[3]))
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sys.stdout.buffer.write(token)
sys.stdout.buffer.flush()
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def genanswer(bool):
answer = 0
if bool:
answer = 1
token = struct.pack('>hh', 2, answer)
return token
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def get_password(user, host):
# Right now we ignore the host component, as Mastodon doesn't store it for local accounts.
# It may be required one day, so the code to handle passing it to the query is left in for now.
cursor = database.cursor()
cursor.execute(db_query_getpass, {"user": user.lower(), "host": host})
data = cursor.fetchone()
cursor.close()
return data[0] if data != None else None
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def isuser(user, host):
return get_password(user, host) != None
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def auth(user, host, password):
db_password = get_password(user, host)
if db_password == None:
logging.debug("Wrong username: %s@%s" % (user, host))
return False
else:
if bcrypt.checkpw(password.encode('utf8'), db_password.encode('utf8')):
logging.debug("Validated %s against hash %s" % (user, db_password))
return True
else:
logging.debug("Wrong password for user: %s@%s" % (user, host))
return False
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########################################################################
# Main Loop
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########################################################################
exitcode = 0
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while True:
logging.debug("start of infinite loop")
try:
ejab_request = ejabberd_in().split(':', 3)
except EOFError:
break
except Exception as e:
logging.exception("Exception occured while reading stdin")
raise
op_result = False
try:
# Only 'auth' and 'isuser' implemented, placeholders left to maybe
# expose other functions later but for now let's not even think about
# modifying the Mastodon DB
if ejab_request[0] == "auth":
op_result = auth(ejab_request[1], ejab_request[2], ejab_request[3])
elif ejab_request[0] == "isuser":
op_result = isuser(ejab_request[1], ejab_request[2])
elif ejab_request[0] == "setpass":
op_result = False
elif ejab_request[0] == "tryregister":
op_result = False
elif ejab_request[0] == "removeuser":
op_result = False
elif ejab_request[0] == "removeuser3":
op_result = False
except Exception:
logging.exception("Exception occured")
ejabberd_out(op_result)
logging.info("successful" if op_result else "unsuccessful")
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logging.debug("end of infinite loop")
logging.info('extauth script terminating')
database.close()
sys.exit(exitcode)