Commit 6e2f0aa8 authored Feb 12, 2013 by Florian Westphal Committed by Pablo Neira Ayuso Feb 12, 2013

netfilter: nf_ct_helper: don't discard helper if it is actually the same



commit (32f53760 netfilter: nf_ct_helper: disable automatic helper
re-assignment of different type) broke transparent proxy scenarios.

For example, initial helper lookup might yield "ftp" (dport 21),
while re-lookup after REDIRECT yields "ftp-2121".

This causes the autoassign code to toss the ftp helper, even
though these are just different instances of the same helper.

Change the test to check for the helper function address instead
of the helper address, as suggested by Pablo.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>

parent 442fad94

net/netfilter/nf_conntrack_helper.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -236,7 +236,9 @@ int __nf_ct_try_assign_helper(struct nf_conn ct, struct nf_conn tmpl,
		/* We only allow helper re-assignment of the same sort since
		* we cannot reallocate the helper extension area.
		*/
		if (help->helper != helper) {
		struct nf_conntrack_helper *tmp = rcu_dereference(help->helper);

		if (tmp && tmp->help != helper->help) {
		RCU_INIT_POINTER(help->helper, NULL);
		goto out;
		}