From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79A91C43331 for ; Fri, 27 Mar 2020 02:25:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DF9520774 for ; Fri, 27 Mar 2020 02:25:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727705AbgC0CZL (ORCPT ); Thu, 26 Mar 2020 22:25:11 -0400 Received: from Chamillionaire.breakpoint.cc ([193.142.43.52]:41652 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbgC0CZK (ORCPT ); Thu, 26 Mar 2020 22:25:10 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1jHegG-00068x-UQ; Fri, 27 Mar 2020 03:25:09 +0100 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH nf-next 3/4] netfilter: nf_queue: do not release refcouts until nf_reinject is done Date: Fri, 27 Mar 2020 03:24:48 +0100 Message-Id: <20200327022449.7411-4-fw@strlen.de> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200327022449.7411-1-fw@strlen.de> References: <20200327022449.7411-1-fw@strlen.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org nf_queue is problematic when another NF_QUEUE invocation happens from nf_reinject(). 1. nf_queue is invoked, increments state->sk refcount. 2. skb is queued, waiting for verdict. 3. sk is closed/released. 3. verdict comes back, nf_reinject is called. 4. nf_reinject drops the reference -- refcount can now drop to 0 Instead of get_ref/release_ref pattern, we need to nest the get_ref calls: get_ref get_ref release_ref release_ref So that when we invoke the next processing stage (another netfilter or the okfn()), we hold at least one reference count on the devices/socket. After previous patch, it is now safe to put the entry even after okfn() has potentially free'd the skb. Signed-off-by: Florian Westphal --- net/netfilter/nf_queue.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index 96eb72908467..aadccdd117f0 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -303,12 +303,10 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict) hooks = nf_hook_entries_head(net, pf, entry->state.hook); - nf_queue_entry_release_refs(entry); - i = entry->hook_index; if (WARN_ON_ONCE(!hooks || i >= hooks->num_hook_entries)) { kfree_skb(skb); - kfree(entry); + nf_queue_entry_free(entry); return; } @@ -347,6 +345,6 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict) kfree_skb(skb); } - kfree(entry); + nf_queue_entry_free(entry); } EXPORT_SYMBOL(nf_reinject); -- 2.24.1