From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5E67955E73 for ; Mon, 28 Oct 2024 16:22:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.188.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730132544; cv=none; b=C9Z7GhKxrLC+5QkCW9VSCjcQLflmae4MHLT+rcYuEGEAVI/I1Ijk14dfD2tWSBd7zljoT/ILB8MKKnzlq7RN9XWO+leyVy31YbWuEuJqxb5q4aQxpoVFC/n0fEPz3JyvKz0IEricS94D+/cykl2/FA+qkr+AC2oewcyOw0WZKhw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730132544; c=relaxed/simple; bh=nvTJOq6oizIxETif140+eu4ms2I9z9K3AS3s3n1I+c0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=u7Y9Rge9rk8uoGbvC8W8O1T5/gSS1ZTkPibl+V1oUfwMkg0FHHxz2rhizgUiJHTVfbIPdhjmxVx3GEhB1Ira1gnle5zSGBpOlKKOJGpVD+1nRtTZEvhmSubHbHO/z4c7yFkqs20/gQzBxmecKcEs/pCBinblqlPT1JZDdYm/4rY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; arc=none smtp.client-ip=217.70.188.207 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: fw@strlen.de, phil@nwl.cc, matttbe@kernel.org Subject: [PATCH nf,v2] netfilter: nf_tables: wait for rcu grace period on net_device removal Date: Mon, 28 Oct 2024 17:22:14 +0100 Message-Id: <20241028162214.177671-1-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 8c873e219970 ("netfilter: core: free hooks with call_rcu") removed synchronize_net() call when unregistering basechain hook, however, net_device removal event handler for the NFPROTO_NETDEV was not updated to wait for RCU grace period. Note that 835b803377f5 ("netfilter: nf_tables_netdev: unregister hooks on net_device removal") does not remove basechain rules on device removal, it was just a bit later that I was hinted to remove rules on net_device removal, see 5ebe0b0eec9d ("netfilter: nf_tables: destroy basechain and rules on netdevice removal"). Fixes: 835b803377f5 ("netfilter: nf_tables_netdev: unregister hooks on net_device removal") Signed-off-by: Pablo Neira Ayuso --- v2: use maybe_get_net() otherwise reftracker reports uaf. include/net/netfilter/nf_tables.h | 2 ++ net/netfilter/nf_tables_api.c | 32 +++++++++++++++++++++++++------ 2 files changed, 28 insertions(+), 6 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 91ae20cb7648..8dd8e278843d 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -1120,6 +1120,7 @@ struct nft_chain { char *name; u16 udlen; u8 *udata; + struct rcu_head rcu_head; /* Only used during control plane commit phase: */ struct nft_rule_blob *blob_next; @@ -1282,6 +1283,7 @@ struct nft_table { struct list_head sets; struct list_head objects; struct list_head flowtables; + possible_net_t net; u64 hgenerator; u64 handle; u32 use; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index a24fe62650a7..e226d8d0ca4e 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1495,6 +1495,7 @@ static int nf_tables_newtable(struct sk_buff *skb, const struct nfnl_info *info, INIT_LIST_HEAD(&table->sets); INIT_LIST_HEAD(&table->objects); INIT_LIST_HEAD(&table->flowtables); + write_pnet(&table->net, net); table->family = family; table->flags = flags; table->handle = ++nft_net->table_handle; @@ -11430,22 +11431,41 @@ int nft_data_dump(struct sk_buff *skb, int attr, const struct nft_data *data, } EXPORT_SYMBOL_GPL(nft_data_dump); -int __nft_release_basechain(struct nft_ctx *ctx) +static void __nft_release_basechain_rcu(struct rcu_head *head) { + struct nft_chain *chain = container_of(head, struct nft_chain, rcu_head); struct nft_rule *rule, *nr; + struct nft_ctx ctx = { + .family = chain->table->family, + .net = read_pnet(&chain->table->net), + }; + + list_for_each_entry_safe(rule, nr, &chain->rules, list) { + list_del(&rule->list); + nf_tables_rule_release(&ctx, rule); + } + nf_tables_chain_destroy(chain); + put_net(ctx.net); +} + +int __nft_release_basechain(struct nft_ctx *ctx) +{ + struct nft_rule *rule; if (WARN_ON(!nft_is_base_chain(ctx->chain))) return 0; + if (!maybe_get_net(ctx->net)) + return 0; + nf_tables_unregister_hook(ctx->net, ctx->chain->table, ctx->chain); - list_for_each_entry_safe(rule, nr, &ctx->chain->rules, list) { - list_del(&rule->list); + list_for_each_entry(rule, &ctx->chain->rules, list) nft_use_dec(&ctx->chain->use); - nf_tables_rule_release(ctx, rule); - } + nft_chain_del(ctx->chain); nft_use_dec(&ctx->table->use); - nf_tables_chain_destroy(ctx->chain); + + call_rcu(&ctx->chain->rcu_head, __nft_release_basechain_rcu); return 0; } -- 2.30.2