From patchwork Wed Nov 6 23:46:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 13865642 X-Patchwork-Delegate: kuba@kernel.org Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 489EC20EA26; Wed, 6 Nov 2024 23:46:45 +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=1730936806; cv=none; b=sAJxIJ9DDXBVmJPX0Tl70i5Clhl0RkYQkKhywy3iQcGpHy3T3OmvotZuEwhJ7clKbJcIPAFFrk4QQ+k6WH6cC7s5EZWPcB5PdJTTgR3+tlECuz3qevRYMGcP/9VcQtqm22lKwlRJHQkWW6whPnObxOmMRTrx5lqsUCk26k3EMIU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730936806; c=relaxed/simple; bh=G1adiYwVMrktORMer56qqXyb91XcP+g6hjmFt5htjaA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=n0imwvqnWVM1eTgC1BtIzLjwfMJfS4/yzFfG8x5ki0eI16oeMYXrC+jM+Nwg/G/REmpcfl8wXeoRTyaM19gURhufXnHuKIMsOS0NnwUB9oUATVSkdQskdjQ8uCMepnNqDjd0EW5Q2mwez71UlUg4GKujW7YCDI0eaIdnHB2AloE= 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: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de Subject: [PATCH net-next 10/11] netfilter: nf_tables: must hold rcu read lock while iterating expression type list Date: Thu, 7 Nov 2024 00:46:24 +0100 Message-Id: <20241106234625.168468-11-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20241106234625.168468-1-pablo@netfilter.org> References: <20241106234625.168468-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Florian Westphal nft shell tests trigger: WARNING: suspicious RCU usage net/netfilter/nf_tables_api.c:3125 RCU-list traversed in non-reader section!! 1 lock held by nft/2068: #0: ffff888106c6f8c8 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_valid_genid+0x3c/0xf0 But the transaction mutex doesn't protect this list, the nfnl subsystem mutex would, but we can't acquire it here without risk of ABBA deadlocks. Acquire the rcu read lock to avoid this issue. v3: add a comment that explains the ->inner_ops check implies expression is builtin and lack of a module owner reference is ok. Fixes: 3a07327d10a0 ("netfilter: nft_inner: support for inner tunnel header matching") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 3b5154f2dd79..de8e48a5c62d 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3296,25 +3296,37 @@ int nft_expr_inner_parse(const struct nft_ctx *ctx, const struct nlattr *nla, if (!tb[NFTA_EXPR_DATA] || !tb[NFTA_EXPR_NAME]) return -EINVAL; + rcu_read_lock(); + type = __nft_expr_type_get(ctx->family, tb[NFTA_EXPR_NAME]); - if (!type) - return -ENOENT; + if (!type) { + err = -ENOENT; + goto out_unlock; + } - if (!type->inner_ops) - return -EOPNOTSUPP; + if (!type->inner_ops) { + err = -EOPNOTSUPP; + goto out_unlock; + } err = nla_parse_nested_deprecated(info->tb, type->maxattr, tb[NFTA_EXPR_DATA], type->policy, NULL); if (err < 0) - goto err_nla_parse; + goto out_unlock; info->attr = nla; info->ops = type->inner_ops; + /* No module reference will be taken on type->owner. + * Presence of type->inner_ops implies that the expression + * is builtin, so it cannot go away. + */ + rcu_read_unlock(); return 0; -err_nla_parse: +out_unlock: + rcu_read_unlock(); return err; }