From patchwork Wed Sep 20 08:41:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13392293 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 895CA11708 for ; Wed, 20 Sep 2023 08:42:18 +0000 (UTC) Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3144B93; Wed, 20 Sep 2023 01:42:17 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qismj-0004xM-2C; Wed, 20 Sep 2023 10:42:13 +0200 From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , Jozsef Kadlecsik , Kyle Zeng Subject: [PATCH net 3/3] netfilter: ipset: Fix race between IPSET_CMD_CREATE and IPSET_CMD_SWAP Date: Wed, 20 Sep 2023 10:41:51 +0200 Message-ID: <20230920084156.4192-4-fw@strlen.de> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230920084156.4192-1-fw@strlen.de> References: <20230920084156.4192-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org From: Jozsef Kadlecsik Kyle Zeng reported that there is a race between IPSET_CMD_ADD and IPSET_CMD_SWAP in netfilter/ip_set, which can lead to the invocation of `__ip_set_put` on a wrong `set`, triggering the `BUG_ON(set->ref == 0);` check in it. The race is caused by using the wrong reference counter, i.e. the ref counter instead of ref_netlink. Fixes: 24e227896bbf ("netfilter: ipset: Add schedule point in call_ad().") Reported-by: Kyle Zeng Closes: https://lore.kernel.org/netfilter-devel/ZPZqetxOmH+w%2Fmyc@westworld/#r Tested-by: Kyle Zeng Signed-off-by: Jozsef Kadlecsik Signed-off-by: Florian Westphal --- net/netfilter/ipset/ip_set_core.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index e564b5174261..35d2f9c9ada0 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -682,6 +682,14 @@ __ip_set_put(struct ip_set *set) /* set->ref can be swapped out by ip_set_swap, netlink events (like dump) need * a separate reference counter */ +static void +__ip_set_get_netlink(struct ip_set *set) +{ + write_lock_bh(&ip_set_ref_lock); + set->ref_netlink++; + write_unlock_bh(&ip_set_ref_lock); +} + static void __ip_set_put_netlink(struct ip_set *set) { @@ -1693,11 +1701,11 @@ call_ad(struct net *net, struct sock *ctnl, struct sk_buff *skb, do { if (retried) { - __ip_set_get(set); + __ip_set_get_netlink(set); nfnl_unlock(NFNL_SUBSYS_IPSET); cond_resched(); nfnl_lock(NFNL_SUBSYS_IPSET); - __ip_set_put(set); + __ip_set_put_netlink(set); } ip_set_lock(set);