From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbeE3LUa (ORCPT ); Wed, 30 May 2018 07:20:30 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60995 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733AbeE3LHH (ORCPT ); Wed, 30 May 2018 07:07:07 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Pablo Neira Ayuso" , "Florian Westphal" , "Cong Wang" , "" , "Eric Dumazet" Date: Wed, 30 May 2018 11:52:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 076/153] netfilter: xt_RATEEST: acquire xt_rateest_mutex for hash insert In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.102-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang commit 7dc68e98757a8eccf8ca7a53a29b896f1eef1f76 upstream. rateest_hash is supposed to be protected by xt_rateest_mutex, and, as suggested by Eric, lookup and insert should be atomic, so we should acquire the xt_rateest_mutex once for both. So introduce a non-locking helper for internal use and keep the locking one for external. Reported-by: Fixes: 5859034d7eb8 ("[NETFILTER]: x_tables: add RATEEST target") Signed-off-by: Cong Wang Reviewed-by: Florian Westphal Reviewed-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- net/netfilter/xt_RATEEST.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) --- a/net/netfilter/xt_RATEEST.c +++ b/net/netfilter/xt_RATEEST.c @@ -40,24 +40,32 @@ static void xt_rateest_hash_insert(struc hlist_add_head(&est->list, &rateest_hash[h]); } -struct xt_rateest *xt_rateest_lookup(const char *name) +static struct xt_rateest *__xt_rateest_lookup(const char *name) { struct xt_rateest *est; struct hlist_node *n; unsigned int h; h = xt_rateest_hash(name); - mutex_lock(&xt_rateest_mutex); hlist_for_each_entry(est, n, &rateest_hash[h], list) { if (strcmp(est->name, name) == 0) { est->refcnt++; - mutex_unlock(&xt_rateest_mutex); return est; } } - mutex_unlock(&xt_rateest_mutex); + return NULL; } + +struct xt_rateest *xt_rateest_lookup(const char *name) +{ + struct xt_rateest *est; + + mutex_lock(&xt_rateest_mutex); + est = __xt_rateest_lookup(name); + mutex_unlock(&xt_rateest_mutex); + return est; +} EXPORT_SYMBOL_GPL(xt_rateest_lookup); void xt_rateest_put(struct xt_rateest *est) @@ -105,8 +113,10 @@ static int xt_rateest_tg_checkentry(cons rnd_inited = true; } - est = xt_rateest_lookup(info->name); + mutex_lock(&xt_rateest_mutex); + est = __xt_rateest_lookup(info->name); if (est) { + mutex_unlock(&xt_rateest_mutex); /* * If estimator parameters are specified, they must match the * existing estimator. @@ -144,11 +154,13 @@ static int xt_rateest_tg_checkentry(cons info->est = est; xt_rateest_hash_insert(est); + mutex_unlock(&xt_rateest_mutex); return 0; err2: kfree(est); err1: + mutex_unlock(&xt_rateest_mutex); return ret; }