https://bugs.openldap.org/show_bug.cgi?id=10360

Issue ID: 10360 Summary: delta-sync can apply old mods Product: OpenLDAP Version: 2.6.9 Hardware: All OS: All Status: UNCONFIRMED Keywords: needs_review Severity: normal Priority: --- Component: slapd Assignee: bugs@openldap.org Reporter: hyc@openldap.org Target Milestone: ---

This might be related to #10358, but not sure.

In delta MPR, if an older mod is received on an entry after a newer mod has already been applied by a local user, the older mod is applied and the newer mod is lost.

The incoming replication ops are checked for freshness by check_csn_age() but that only checks the incoming cookieCSN against contextCSNs of the same SID. I.e., that check only prevents duplicate mods being replicated multiple times from the same remote provider. If check_csn_age() passes, then syncrepl_message_to_op() is invoked which just applies the mod. It doesn't check the mod or cookieCSN against the entry's current entryCSN.

The code in syncrepl_op_mod() performs the checks we need. The code just needs to be pulled into a new function so it can be used in both places.