From f6817cae5e7435ef25be13bddf24a3c33b5623b9 Mon Sep 17 00:00:00 2001 From: Simo Sorce Date: Thu, 23 Mar 2017 17:49:27 -0400 Subject: Prevent churn on ccaches We slice down the received cookie so that just the content that matter is preserved. Thi is ok because servers can't trust anything else anyway and will accept a cookie with the ancillary data missing. By removing variable parts like the expiry component added by mod_session or the Expiration or Max-Age metadata we keep only the part of the cookie that changes only when a new session is generated. This way when storing the cookie we actually add a new entry in the ccache only when the session actually changes, and this prevents churn on FILE based ccaches. Related https://pagure.io/freeipa/issue/6775 Signed-off-by: Simo Sorce --- ipalib/rpc.py | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/ipalib/rpc.py b/ipalib/rpc.py index f597ce0b7..e23ca3d06 100644 --- a/ipalib/rpc.py +++ b/ipalib/rpc.py @@ -38,6 +38,7 @@ import os import locale import base64 import json +import re import socket import gzip @@ -737,6 +738,20 @@ class KerbTransport(SSLTransport): self.send_content(connection, request_body) return connection + # Find all occurrences of the expiry component + expiry_re = re.compile(r'.*?(&expiry=\d+).*?') + + def _slice_session_cookie(self, session_cookie): + # Keep only the cookie value and strip away all other info. + # This is to reduce the churn on FILE ccaches which grow every time we + # set new data. The expiration time for the cookie is set in the + # encrypted data anyway and will be enforced by the server + http_cookie = session_cookie.http_cookie() + # We also remove the "expiry" part from the data which is not required + for exp in self.expiry_re.findall(http_cookie): + http_cookie = http_cookie.replace(exp, '') + return http_cookie + def store_session_cookie(self, cookie_header): ''' Given the contents of a Set-Cookie header scan the header and @@ -787,7 +802,7 @@ class KerbTransport(SSLTransport): if session_cookie is None: return - cookie_string = str(session_cookie) + cookie_string = self._slice_session_cookie(session_cookie) root_logger.debug("storing cookie '%s' for principal %s", cookie_string, principal) try: update_persistent_client_session_data(principal, cookie_string) -- cgit