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Commit 4401a862 authored by Patrick McHardy's avatar Patrick McHardy Committed by Pablo Neira Ayuso
Browse files

netfilter: nf_tables: restore chain change atomicity 



Chain counter validation is performed after the chain policy has
potentially been changed. Move counter validation/setting before
changing of the chain policy to fix this.

Additionally fix a memory leak if chain counter allocation fails
for new chains, remove an unnecessary free_percpu() and move
counter allocation for new chains

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 57de2a0c

net/netfilter/nf_tables_api.c

+21 −22
Original line number Diff line number Diff line
@@ -880,9 +880,6 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb, 
		    !IS_ERR(nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME])))

			return -EEXIST;



		if (nla[NFTA_CHAIN_POLICY])

			nft_base_chain(chain)->policy = policy;



		if (nla[NFTA_CHAIN_COUNTERS]) {

			if (!(chain->flags & NFT_BASE_CHAIN))

				return -EOPNOTSUPP;
@@ -893,6 +890,9 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb, 
				return err;

		}



		if (nla[NFTA_CHAIN_POLICY])

			nft_base_chain(chain)->policy = policy;



		if (nla[NFTA_CHAIN_HANDLE] && name)

			nla_strlcpy(chain->name, name, NFT_CHAIN_MAXNAMELEN);
@@ -934,6 +934,24 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb, 
		if (basechain == NULL)

			return -ENOMEM;



		if (nla[NFTA_CHAIN_COUNTERS]) {

			err = nf_tables_counters(basechain,

						 nla[NFTA_CHAIN_COUNTERS]);

			if (err < 0) {

				kfree(basechain);

				return err;

			}

		} else {

			struct nft_stats __percpu *newstats;



			newstats = alloc_percpu(struct nft_stats);

			if (newstats == NULL) {

				kfree(basechain);

				return -ENOMEM;

			}

			rcu_assign_pointer(basechain->stats, newstats);

		}



		basechain->type = type;

		chain = &basechain->chain;
@@ -953,25 +971,6 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb, 


		chain->flags |= NFT_BASE_CHAIN;

		basechain->policy = policy;



		if (nla[NFTA_CHAIN_COUNTERS]) {

			err = nf_tables_counters(basechain,

						 nla[NFTA_CHAIN_COUNTERS]);

			if (err < 0) {

				free_percpu(basechain->stats);

				kfree(basechain);

				return err;

			}

		} else {

			struct nft_stats __percpu *newstats;



			newstats = alloc_percpu(struct nft_stats);

			if (newstats == NULL)

				return -ENOMEM;



			rcu_assign_pointer(nft_base_chain(chain)->stats,

					   newstats);

		}

	} else {

		chain = kzalloc(sizeof(*chain), GFP_KERNEL);

		if (chain == NULL)