From patchwork Mon Apr 29 12:24:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: shaozhengchao X-Patchwork-Id: 13646823 X-Patchwork-Delegate: kuba@kernel.org Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (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 8AE6782891; Mon, 29 Apr 2024 12:19:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714393176; cv=none; b=cccXVK4PGAIHa61gMRoteG+7z7fOH+VmbP3tGtlyxKo3TOe5C6H/1g0laRut2QEfEY74Oh0/UVW/HH1K1/4eQiUcJbt8wXHw0srSpKEIiyooZFvM8OdBe/dqT8XtRwAs8LuC/sAThRnloSeKGpK937WngpsuP03DJMmdMJYUnrw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714393176; c=relaxed/simple; bh=EuQXV16l51UdqXlNOFlk5BTZ+baCxzwtTCa+CuuHdsU=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ikLR2/N+NWW5PCKS09yTLsqY386L2MQhVLn+LEs41khhmJwqLcM9ZHsPfEuS8KfKql7DTueBugVlizw67tcU9zS44Hs7AOZVvCdJ4S/6UahrI/n+gRe3Ivp6mJ2sSNO41XGtoHzshcdKuMQUDBCqD3aRYPYGIc7XAXYeeS38hao= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4VSj3f6dtRzwT0j; Mon, 29 Apr 2024 20:16:14 +0800 (CST) Received: from dggpeml500026.china.huawei.com (unknown [7.185.36.106]) by mail.maildlp.com (Postfix) with ESMTPS id 3E24118007C; Mon, 29 Apr 2024 20:19:31 +0800 (CST) Received: from huawei.com (10.175.101.6) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Mon, 29 Apr 2024 20:19:30 +0800 From: Zhengchao Shao To: CC: , , , , , , , , , , Subject: [PATCH stable,5.15 1/2] tcp: Clean up kernel listener's reqsk in inet_twsk_purge() Date: Mon, 29 Apr 2024 20:24:47 +0800 Message-ID: <20240429122448.2661647-2-shaozhengchao@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240429122448.2661647-1-shaozhengchao@huawei.com> References: <20240429122448.2661647-1-shaozhengchao@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500026.china.huawei.com (7.185.36.106) X-Patchwork-Delegate: kuba@kernel.org From: Kuniyuki Iwashima commit 740ea3c4a0b2e326b23d7cdf05472a0e92aa39bc upstream Eric Dumazet reported a use-after-free related to the per-netns ehash series. [0] When we create a TCP socket from userspace, the socket always holds a refcnt of the netns. This guarantees that a reqsk timer is always fired before netns dismantle. Each reqsk has a refcnt of its listener, so the listener is not freed before the reqsk, and the net is not freed before the listener as well. OTOH, when in-kernel users create a TCP socket, it might not hold a refcnt of its netns. Thus, a reqsk timer can be fired after the netns dismantle and access freed per-netns ehash. To avoid the use-after-free, we need to clean up TCP_NEW_SYN_RECV sockets in inet_twsk_purge() if the netns uses a per-netns ehash. [0]: https://lore.kernel.org/netdev/CANn89iLXMup0dRD_Ov79Xt8N9FM0XdhCHEN05sf3eLwxKweM6w@mail.gmail.com/ BUG: KASAN: use-after-free in tcp_or_dccp_get_hashinfo include/net/inet_hashtables.h:181 [inline] BUG: KASAN: use-after-free in reqsk_queue_unlink+0x320/0x350 net/ipv4/inet_connection_sock.c:913 Read of size 8 at addr ffff88807545bd80 by task syz-executor.2/8301 CPU: 1 PID: 8301 Comm: syz-executor.2 Not tainted 6.0.0-syzkaller-02757-gaf7d23f9d96a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 tcp_or_dccp_get_hashinfo include/net/inet_hashtables.h:181 [inline] reqsk_queue_unlink+0x320/0x350 net/ipv4/inet_connection_sock.c:913 inet_csk_reqsk_queue_drop net/ipv4/inet_connection_sock.c:927 [inline] inet_csk_reqsk_queue_drop_and_put net/ipv4/inet_connection_sock.c:939 [inline] reqsk_timer_handler+0x724/0x1160 net/ipv4/inet_connection_sock.c:1053 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107 Fixes: d1e5e6408b30 ("tcp: Introduce optional per-netns ehash.") Reported-by: syzbot Reported-by: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20221012145036.74960-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski [shaozhengchao: resolved conflicts in 5.15] Signed-off-by: Zhengchao Shao --- net/ipv4/inet_timewait_sock.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c index 437afe392e66..9b891d6296ec 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -268,8 +268,21 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family) rcu_read_lock(); restart: sk_nulls_for_each_rcu(sk, node, &head->chain) { - if (sk->sk_state != TCP_TIME_WAIT) + if (sk->sk_state != TCP_TIME_WAIT) { + /* A kernel listener socket might not hold refcnt for net, + * so reqsk_timer_handler() could be fired after net is + * freed. Userspace listener and reqsk never exist here. + */ + if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV && + hashinfo->pernet)) { + struct request_sock *req = inet_reqsk(sk); + + inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req); + } + continue; + } + tw = inet_twsk(sk); if ((tw->tw_family != family) || refcount_read(&twsk_net(tw)->ns.count))