ipvs: add missing ip_vs_pe_put in sync code

commit 528c943f upstream.

ip_vs_conn_fill_param_sync() gets in param.pe a module
reference for persistence engine from __ip_vs_pe_getbyname()
but forgets to put it. Problem occurs in backup for
sync protocol v1 (2.6.39).

Also, pe_data usually comes in sync messages for
connection templates and ip_vs_conn_new() copies
the pointer only in this case. Make sure pe_data
is not leaked if it comes unexpectedly for normal
connections. Leak can happen only if bogus messages
are sent to backup server.

Fixes: fe5e7a1e ("IPVS: Backup, Adding Version 1 receive capability")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

net/netfilter/ipvs/ip_vs_sync.c

@@ -763,6 +763,8 @@ static void ip_vs_proc_conn(struct net *net, struct ip_vs_conn_param *param,
 			IP_VS_DBG(2, "BACKUP, add new conn. failed\n");
 			return;
 		}
+		if (!(flags & IP_VS_CONN_F_TEMPLATE))
+			kfree(param->pe_data);
 	} else if (!cp->dest) {
 		dest = ip_vs_try_bind_dest(cp);
 		if (dest)
@@ -1064,6 +1066,7 @@ static inline int ip_vs_proc_sync_conn(struct net *net, __u8 *p, __u8 *msg_end)
 				(opt_flags & IPVS_OPT_F_SEQ_DATA ? &opt : NULL)
 				);
 #endif
+	ip_vs_pe_put(param.pe);
 	return 0;
 	/* Error exit */
 out: