mirror of
https://github.com/mail-in-a-box/mailinabox.git
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130 lines
4.4 KiB
Python
130 lines
4.4 KiB
Python
import base64, os, os.path, hmac
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from flask import make_response
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import utils
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from mailconfig import get_mail_password, get_mail_user_privileges
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DEFAULT_KEY_PATH = '/var/lib/mailinabox/api.key'
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DEFAULT_AUTH_REALM = 'Mail-in-a-Box Management Server'
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class KeyAuthService:
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"""Generate an API key for authenticating clients
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Clients must read the key from the key file and send the key with all HTTP
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requests. The key is passed as the username field in the standard HTTP
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Basic Auth header.
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"""
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def __init__(self):
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self.auth_realm = DEFAULT_AUTH_REALM
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self.key = self._generate_key()
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self.key_path = DEFAULT_KEY_PATH
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def write_key(self):
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"""Write key to file so authorized clients can get the key
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The key file is created with mode 0640 so that additional users can be
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authorized to access the API by granting group/ACL read permissions on
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the key file.
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"""
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def create_file_with_mode(path, mode):
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# Based on answer by A-B-B: http://stackoverflow.com/a/15015748
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old_umask = os.umask(0)
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try:
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return os.fdopen(os.open(path, os.O_WRONLY | os.O_CREAT, mode), 'w')
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finally:
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os.umask(old_umask)
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os.makedirs(os.path.dirname(self.key_path), exist_ok=True)
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with create_file_with_mode(self.key_path, 0o640) as key_file:
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key_file.write(self.key + '\n')
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def authenticate(self, request, env):
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"""Test if the client key passed in HTTP Authorization header matches the service key
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or if the or username/password passed in the header matches an administrator user.
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Returns a tuple of the user's email address and list of user privileges (e.g.
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('my@email', []) or ('my@email', ['admin']); raises a ValueError on login failure.
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If the user used an API key, the user's email is returned as None."""
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def decode(s):
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return base64.b64decode(s.encode('ascii')).decode('ascii')
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def parse_basic_auth(header):
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if " " not in header:
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return None, None
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scheme, credentials = header.split(maxsplit=1)
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if scheme != 'Basic':
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return None, None
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credentials = decode(credentials)
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if ":" not in credentials:
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return None, None
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username, password = credentials.split(':', maxsplit=1)
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return username, password
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header = request.headers.get('Authorization')
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if not header:
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raise ValueError("No authorization header provided.")
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username, password = parse_basic_auth(header)
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if username in (None, ""):
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raise ValueError("Authorization header invalid.")
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elif username == self.key:
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# The user passed the API key which grants administrative privs.
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return (None, ["admin"])
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else:
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# The user is trying to log in with a username and user-specific
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# API key or password. Raises or returns privs.
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return (username, self.get_user_credentials(username, password, env))
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def get_user_credentials(self, email, pw, env):
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# Validate a user's credentials. On success returns a list of
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# privileges (e.g. [] or ['admin']). On failure raises a ValueError
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# with a login error message.
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# Sanity check.
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if email == "" or pw == "":
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raise ValueError("Enter an email address and password.")
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# The password might be a user-specific API key.
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if hmac.compare_digest(self.create_user_key(email), pw):
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# OK.
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pass
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else:
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# Get the hashed password of the user. Raise a ValueError if the
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# email address does not correspond to a user.
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pw_hash = get_mail_password(email, env)
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# Authenticate.
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try:
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# Use 'doveadm pw' to check credentials. doveadm will return
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# a non-zero exit status if the credentials are no good,
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# and check_call will raise an exception in that case.
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utils.shell('check_call', [
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"/usr/bin/doveadm", "pw",
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"-p", pw,
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"-t", pw_hash,
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])
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except:
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# Login failed.
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raise ValueError("Invalid password.")
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# Get privileges for authorization. This call should never fail on a valid user,
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# but if the caller passed a user-specific API key then the user may no longer
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# exist --- in that case, get_mail_user_privileges will return a tuple of an
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# error message and an HTTP status code.
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privs = get_mail_user_privileges(email, env)
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if isinstance(privs, tuple): raise ValueError(privs[0])
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# Return a list of privileges.
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return privs
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def create_user_key(self, email):
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return hmac.new(self.key.encode('ascii'), b"AUTH:" + email.encode("utf8"), digestmod="sha1").hexdigest()
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def _generate_key(self):
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raw_key = os.urandom(32)
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return base64.b64encode(raw_key).decode('ascii')
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