diff --git a/ldapauthenticator/ldapauthenticator.py b/ldapauthenticator/ldapauthenticator.py index 1e9f380..719caa2 100644 --- a/ldapauthenticator/ldapauthenticator.py +++ b/ldapauthenticator/ldapauthenticator.py @@ -47,7 +47,8 @@ def _server_port_default(self): help=""" Template from which to construct the full dn when authenticating to LDAP. {username} is replaced - with the actual username used to log in. + with the user's resolved username (i.e. their CN attribute). + {login} is replaced with the actual username used to login. If your LDAP is set in such a way that the userdn can not be formed from a template, but must be looked up with an attribute @@ -62,6 +63,9 @@ def _server_port_default(self): uid={username},ou=people,dc=wikimedia,dc=org, uid={username},ou=Developers,dc=wikimedia,dc=org ] + + Active Directory Example: + DOMAIN\{login} """ ) @@ -137,6 +141,20 @@ def _server_port_default(self): """ ) + group_search_base = Unicode( + config=True, + default=None, + allow_none=True, + help=""" + Base for looking up groups in the directory. Used if `activedirectory` is True. + + For example: + ``` + c.LDAPAuthenticator.group_search_base = 'ou=groups,dc=wikimedia,dc=org' + ``` + """ + ) + user_attribute = Unicode( config=True, default=None, @@ -151,6 +169,66 @@ def _server_port_default(self): """ ) + memberof_attribute = Unicode( + config=True, + default_value='memberOf', + allow_none=False, + help=""" + Attribute attached to user objects containing the list of groups the user is a member of. + + Defaults to 'memberOf', you probably won't need to change this. + """ + ) + + get_groups_from_user = Bool( + False, + config=True, + help=""" + If set, this will confirm a user's group membership by querying the + user object in LDAP directly, and querying the attribute set in + `memberof_attribute` (defaults to `memberOf`). + + If unset (the default), then each authorised group set in + `allowed_group` is queried from LDAP and matched against the user's DN. + + This should be set when the LDAP server is Microsoft Active Directory, + and you probably also want to set the `activedirectory` configuration + setting to 'true' as well' + """ + ) + + activedirectory = Bool( + False, + config=True, + help=""" + If set, this treats the remote LDAP server as a Microsoft Active + Directory instance, and will optimise group membership queries where + `allow_groups` is used. This requires `get_groups_from_user` to be + enabled. + + This allows nested groups to be resolved when using Active Directory. + + Example Active Directory configuration: + ``` + c.LDAPAuthenticator.bind_dn_template = 'DOMAIN\{login}' + c.LDAPAuthenticator.lookup_dn = True + c.LDAPAuthenticator.activedirectory = True + c.LDAPAuthenticator.get_groups_from_user = True + c.LDAPAuthenticator.lookup_dn_user_dn_attribute = 'cn' + c.LDAPAuthenticator.lookup_dn_search_filter = '({login_attr}={login})' + c.LDAPAuthenticator.lookup_dn_search_user = 'readonly' + c.LDAPAuthenticator.lookup_dn_search_password = 'notarealpassword' + c.LDAPAuthenticator.user_attribute = 'sAMAccountName' + c.LDAPAuthenticator.user_search_base = 'OU=Users,DC=example,DC=org' + c.LDAPAuthenticator.group_search_base = 'OU=Groups,DC=example,DC=org' + + c.LDAPAuthenticator.admin_users = {'Administrator'} + c.LDAPAuthenticator.allowed_groups = [ + 'CN=JupyterHub_Users,OU=Groups,DC=example,DC=org'] + ``` + """ + ) + lookup_dn_search_filter = Unicode( config=True, default_value='({login_attr}={login})', @@ -204,7 +282,7 @@ def _server_port_default(self): """ ) - def resolve_username(self, username_supplied_by_user): + def resolve_username(self, username_supplied_by_user, want_dn = False): if self.lookup_dn: server = ldap3.Server( self.server_address, @@ -241,7 +319,10 @@ def resolve_username(self, username_supplied_by_user): self.log.warn('username:%s No such user entry found when looking up with attribute %s', username_supplied_by_user, self.user_attribute) return None - return conn.response[0]['attributes'][self.lookup_dn_user_dn_attribute] + if want_dn: + return conn.response[0]['dn'] + else: + return conn.response[0]['attributes'][self.lookup_dn_user_dn_attribute] else: return username_supplied_by_user @@ -285,6 +366,42 @@ def getConnection(userdn, username, password): ) return conn + def get_user_groups(username): + if self.activedirectory: + self.log.debug('Active Directory enabled') + user_dn = self.resolve_username(username, want_dn=True) + search_filter='(member:1.2.840.113556.1.4.1941:={dn})'.format(dn=self.escape_userdn_if_needed(user_dn)) + search_attribs=['cn'] # We don't actually care, we just want the DN + search_base=self.group_search_base, + self.log.debug('LDAP Group query: user_dn:[%s] filter:[%s]', user_dn, search_filter) + else: + search_filter=self.lookup_dn_search_filter.format(login_attr=self.user_attribute, login=username) + search_attribs=[self.memberof_attribute] + search_base=self.user_search_base, + self.log.debug('LDAP Group query: username:[%s] filter:[%s]', username, search_filter) + + conn.search( + search_base=search_base, + search_scope=ldap3.SUBTREE, + search_filter=search_filter, + attributes=search_attribs) + + if self.activedirectory: + user_groups = [] + + if len(conn.response) == 0: + return None + + for g in conn.response: + user_groups.append(g['dn']) + return user_groups + else: + if len(conn.response) == 0 or 'attributes' not in conn.response[0].keys(): + self.log.debug('User %s is not a member of any groups (via memberOf)', username) + return None + else: + return conn.response[0]['attributes'][self.memberof_attribute] + # Protect against invalid usernames as well as LDAP injection attacks if not re.match(self.valid_username_regex, username): self.log.warn('username:%s Illegal characters in username, must match regex %s', username, self.valid_username_regex) @@ -313,7 +430,7 @@ def getConnection(userdn, username, password): bind_dn_template = [bind_dn_template] for dn in bind_dn_template: - userdn = dn.format(username=resolved_username) + userdn = dn.format(username=resolved_username, login=username) msg = 'Status of user bind {username} with {userdn} : {isBound}' try: conn = getConnection(userdn, username, password) @@ -337,22 +454,36 @@ def getConnection(userdn, username, password): if isBound: if self.allowed_groups: self.log.debug('username:%s Using dn %s', username, userdn) - for group in self.allowed_groups: - groupfilter = ( - '(|' - '(member={userdn})' - '(uniqueMember={userdn})' - '(memberUid={uid})' - ')' - ).format(userdn=escape_filter_chars(userdn), uid=escape_filter_chars(username)) - groupattributes = ['member', 'uniqueMember', 'memberUid'] - if conn.search( - group, - search_scope=ldap3.BASE, - search_filter=groupfilter, - attributes=groupattributes - ): - return username + + if self.get_groups_from_user: + user_groups = get_user_groups(username) + if user_groups is None: + self.log.debug('Username %s has no group membership', username) + return None + else: + self.log.debug('Username %s is a member of %d groups', username, len(user_groups)) + for group in self.allowed_groups: + if group in user_groups: + self.log.info('User %s is a member of permitted group %s', username, group) + return username + else: + for group in self.allowed_groups: + groupfilter = ( + '(|' + '(member={userdn})' + '(uniqueMember={userdn})' + '(memberUid={uid})' + ')' + ).format(userdn=escape_filter_chars(userdn), uid=escape_filter_chars(username)) + groupattributes = ['member', 'uniqueMember', 'memberUid'] + if conn.search( + group, + search_scope=ldap3.BASE, + search_filter=groupfilter, + attributes=groupattributes + ): + return username + # If we reach here, then none of the groups matched self.log.warn('username:%s User not in any of the allowed groups', username) return None