Commit 310529e6 authored Dec 30, 2018 by Phil Sutter Committed by Pablo Neira Ayuso Jan 08, 2019

netfilter: nf_tables: Fix for endless loop when dumping ruleset



__nf_tables_dump_rules() stores the current idx value into cb->args[0]
before returning to caller. With multiple chains present, cb->args[0] is
therefore updated after each chain's rules have been traversed. This
though causes the final nf_tables_dump_rules() run (which should return
an skb->len of zero since no rules are left to dump) to continue dumping
rules for each but the first chain. Fix this by moving the cb->args[0]
update to nf_tables_dump_rules().

With no final action to be performed anymore in
__nf_tables_dump_rules(), drop 'out_unfinished' jump label and 'rc'
variable - instead return the appropriate value directly.

Fixes: 241faece ("netfilter: nf_tables: Speed up selective rule dumps")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent a0071840

net/netfilter/nf_tables_api.c

+4 −6

Original line number	Diff line number	Diff line
		@@ -2304,7 +2304,6 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
		struct net *net = sock_net(skb->sk);
		unsigned int s_idx = cb->args[0];
		const struct nft_rule *rule;
		int rc = 1;

		list_for_each_entry_rcu(rule, &chain->rules, list) {
		if (!nft_is_active(net, rule))
		@@ -2321,16 +2320,13 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
		NLM_F_MULTI \| NLM_F_APPEND,
		table->family,
		table, chain, rule) < 0)
		goto out_unfinished;
		return 1;

		nl_dump_check_consistent(cb, nlmsg_hdr(skb));
		cont:
		(*idx)++;
		}
		rc = 0;
		out_unfinished:
		cb->args[0] = *idx;
		return rc;
		return 0;
		}

		static int nf_tables_dump_rules(struct sk_buff *skb,
		@@ -2382,6 +2378,8 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
		}
		done:
		rcu_read_unlock();

		cb->args[0] = idx;
		return skb->len;
		}

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