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netfilter: nf_tables: fix GC transaction races with netns and netlink event exit path
commit6a33d8b73d
upstream. Netlink event path is missing a synchronization point with GC transactions. Add GC sequence number update to netns release path and netlink event path, any GC transaction losing race will be discarded. Fixes:5f68718b34
("netfilter: nf_tables: GC transaction API to avoid race with control plane") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
af78b0489e
commit
6796800f0d
1 changed files with 32 additions and 4 deletions
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@ -9207,6 +9207,22 @@ static void nft_set_commit_update(struct list_head *set_update_list)
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}
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}
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}
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}
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static unsigned int nft_gc_seq_begin(struct nftables_pernet *nft_net)
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{
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unsigned int gc_seq;
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/* Bump gc counter, it becomes odd, this is the busy mark. */
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gc_seq = READ_ONCE(nft_net->gc_seq);
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WRITE_ONCE(nft_net->gc_seq, ++gc_seq);
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return gc_seq;
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}
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static void nft_gc_seq_end(struct nftables_pernet *nft_net, unsigned int gc_seq)
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{
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WRITE_ONCE(nft_net->gc_seq, ++gc_seq);
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}
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static int nf_tables_commit(struct net *net, struct sk_buff *skb)
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static int nf_tables_commit(struct net *net, struct sk_buff *skb)
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{
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{
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struct nftables_pernet *nft_net = nft_pernet(net);
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struct nftables_pernet *nft_net = nft_pernet(net);
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@ -9292,9 +9308,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
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WRITE_ONCE(nft_net->base_seq, base_seq);
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WRITE_ONCE(nft_net->base_seq, base_seq);
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/* Bump gc counter, it becomes odd, this is the busy mark. */
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gc_seq = nft_gc_seq_begin(nft_net);
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gc_seq = READ_ONCE(nft_net->gc_seq);
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WRITE_ONCE(nft_net->gc_seq, ++gc_seq);
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/* step 3. Start new generation, rules_gen_X now in use. */
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/* step 3. Start new generation, rules_gen_X now in use. */
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net->nft.gencursor = nft_gencursor_next(net);
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net->nft.gencursor = nft_gencursor_next(net);
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@ -9485,7 +9499,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
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nf_tables_gen_notify(net, skb, NFT_MSG_NEWGEN);
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nf_tables_gen_notify(net, skb, NFT_MSG_NEWGEN);
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nf_tables_commit_audit_log(&adl, nft_net->base_seq);
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nf_tables_commit_audit_log(&adl, nft_net->base_seq);
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WRITE_ONCE(nft_net->gc_seq, ++gc_seq);
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nft_gc_seq_end(nft_net, gc_seq);
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nf_tables_commit_release(net);
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nf_tables_commit_release(net);
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return 0;
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return 0;
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@ -10468,6 +10482,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
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struct net *net = n->net;
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struct net *net = n->net;
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unsigned int deleted;
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unsigned int deleted;
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bool restart = false;
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bool restart = false;
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unsigned int gc_seq;
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if (event != NETLINK_URELEASE || n->protocol != NETLINK_NETFILTER)
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if (event != NETLINK_URELEASE || n->protocol != NETLINK_NETFILTER)
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return NOTIFY_DONE;
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return NOTIFY_DONE;
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@ -10475,6 +10490,9 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
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nft_net = nft_pernet(net);
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nft_net = nft_pernet(net);
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deleted = 0;
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deleted = 0;
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mutex_lock(&nft_net->commit_mutex);
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mutex_lock(&nft_net->commit_mutex);
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gc_seq = nft_gc_seq_begin(nft_net);
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if (!list_empty(&nf_tables_destroy_list))
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if (!list_empty(&nf_tables_destroy_list))
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nf_tables_trans_destroy_flush_work();
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nf_tables_trans_destroy_flush_work();
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again:
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again:
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@ -10497,6 +10515,8 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
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if (restart)
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if (restart)
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goto again;
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goto again;
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}
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}
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nft_gc_seq_end(nft_net, gc_seq);
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mutex_unlock(&nft_net->commit_mutex);
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mutex_unlock(&nft_net->commit_mutex);
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return NOTIFY_DONE;
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return NOTIFY_DONE;
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@ -10535,12 +10555,20 @@ static void __net_exit nf_tables_pre_exit_net(struct net *net)
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static void __net_exit nf_tables_exit_net(struct net *net)
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static void __net_exit nf_tables_exit_net(struct net *net)
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{
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{
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struct nftables_pernet *nft_net = nft_pernet(net);
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struct nftables_pernet *nft_net = nft_pernet(net);
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unsigned int gc_seq;
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mutex_lock(&nft_net->commit_mutex);
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mutex_lock(&nft_net->commit_mutex);
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gc_seq = nft_gc_seq_begin(nft_net);
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if (!list_empty(&nft_net->commit_list) ||
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if (!list_empty(&nft_net->commit_list) ||
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!list_empty(&nft_net->module_list))
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!list_empty(&nft_net->module_list))
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__nf_tables_abort(net, NFNL_ABORT_NONE);
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__nf_tables_abort(net, NFNL_ABORT_NONE);
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__nft_release_tables(net);
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__nft_release_tables(net);
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nft_gc_seq_end(nft_net, gc_seq);
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mutex_unlock(&nft_net->commit_mutex);
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mutex_unlock(&nft_net->commit_mutex);
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WARN_ON_ONCE(!list_empty(&nft_net->tables));
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WARN_ON_ONCE(!list_empty(&nft_net->tables));
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WARN_ON_ONCE(!list_empty(&nft_net->module_list));
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WARN_ON_ONCE(!list_empty(&nft_net->module_list));
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