(ITS#5597) syncrepl can fail to compare CSN from provider

[rein@OpenLDAP.org]

Full_Name: Rein Tollevik
Version: CVS head
OS: linux, solaris
URL: 
Submission from: (NULL) (84.215.36.97)
Submitted by: rein


If the syncrepl provider presents the same (or a lower) number of contextCSN
values than the consumer has, but with other sid values, it can fail to update
its values.
This is mostly seen in a multiple masters (as opposed to a multi-master)
configuration.

The patch at the end should fix that.  Does it look OK Howard?

Rein Tollevik
Basefarm AS

Index: syncrepl.c
===================================================================
RCS file: /repo/OpenLDAP/pkg/ldap/servers/slapd/syncrepl.c,v
retrieving revision 1.405
diff -u -u -r1.405 syncrepl.c
--- syncrepl.c	4 Jul 2008 21:44:39 -0000	1.405
+++ syncrepl.c	4 Jul 2008 21:48:13 -0000
@@ -689,8 +689,8 @@
 		return -1;
 	}
 
-	for (i=0; i<sc1->numcsns; i++) {
-		for (j=0; j<sc2->numcsns; j++) {
+	for (j=0; j<sc2->numcsns; j++) {
+		for (i=0; i<sc1->numcsns; i++) {
 			if ( sc1->sids[i] != sc2->sids[j] )
 				continue;
 			value_match( &match, slap_schema.si_ad_entryCSN,
@@ -703,6 +703,11 @@
 			}
 			break;
 		}
+		if ( i == sc1->numcsns ) {
+			/* sc2 has a sid sc1 lacks */
+			*which = j;
+			return -1;
+		}
 	}
 	return match;
 }