From patchwork Sat Oct 9 07:40:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Ziyang Xuan (William)" X-Patchwork-Id: 12547339 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F231C433EF for ; Sat, 9 Oct 2021 07:41:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F28960F6D for ; Sat, 9 Oct 2021 07:41:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232931AbhJIHn2 (ORCPT ); Sat, 9 Oct 2021 03:43:28 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:13712 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229804AbhJIHnZ (ORCPT ); Sat, 9 Oct 2021 03:43:25 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HRH5R2SybzW2Wm; Sat, 9 Oct 2021 15:39:55 +0800 (CST) Received: from localhost.localdomain (10.175.104.82) by dggeml757-chm.china.huawei.com (10.1.199.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Sat, 9 Oct 2021 15:41:27 +0800 From: Ziyang Xuan To: , CC: , , , , Subject: [PATCH net v2 1/2] can: isotp: add result check for wait_event_interruptible() Date: Sat, 9 Oct 2021 15:40:18 +0800 Message-ID: <10ca695732c9dd267c76a3c30f37aefe1ff7e32f.1633764159.git.william.xuanziyang@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.175.104.82] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggeml757-chm.china.huawei.com (10.1.199.137) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Using wait_event_interruptible() to wait for complete transmission, but do not check the result of wait_event_interruptible() which can be interrupted. It will result in tx buffer has multiple accessers and the later process interferes with the previous process. Following is one of the problems reported by syzbot. ============================================================= WARNING: CPU: 0 PID: 0 at net/can/isotp.c:840 isotp_tx_timer_handler+0x2e0/0x4c0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.13.0-rc7+ #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:isotp_tx_timer_handler+0x2e0/0x4c0 Call Trace: ? isotp_setsockopt+0x390/0x390 __hrtimer_run_queues+0xb8/0x610 hrtimer_run_softirq+0x91/0xd0 ? rcu_read_lock_sched_held+0x4d/0x80 __do_softirq+0xe8/0x553 irq_exit_rcu+0xf8/0x100 sysvec_apic_timer_interrupt+0x9e/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 Add result check for wait_event_interruptible() in isotp_sendmsg() to avoid multiple accessers for tx buffer. Reported-by: syzbot+78bab6958a614b0c80b9@syzkaller.appspotmail.com Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Signed-off-by: Ziyang Xuan Acked-by: Oliver Hartkopp --- net/can/isotp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index caaa532ece94..2ac29c2b2ca6 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -865,7 +865,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) return -EAGAIN; /* wait for complete transmission of current pdu */ - wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + if (err) + return err; } if (!size || size > MAX_MSG_LENGTH) From patchwork Sat Oct 9 07:40:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Ziyang Xuan (William)" X-Patchwork-Id: 12547341 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE84DC433FE for ; Sat, 9 Oct 2021 07:41:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B34FF60F90 for ; Sat, 9 Oct 2021 07:41:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233082AbhJIHnh (ORCPT ); Sat, 9 Oct 2021 03:43:37 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:13713 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232955AbhJIHnh (ORCPT ); Sat, 9 Oct 2021 03:43:37 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HRH5f42whzWZKb; Sat, 9 Oct 2021 15:40:06 +0800 (CST) Received: from localhost.localdomain (10.175.104.82) by dggeml757-chm.china.huawei.com (10.1.199.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Sat, 9 Oct 2021 15:41:38 +0800 From: Ziyang Xuan To: , CC: , , , , Subject: [PATCH net v2 2/2] can: isotp: fix tx buffer concurrent access in isotp_sendmsg() Date: Sat, 9 Oct 2021 15:40:30 +0800 Message-ID: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.175.104.82] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggeml757-chm.china.huawei.com (10.1.199.137) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When isotp_sendmsg() concurrent, tx.state of all tx processes can be ISOTP_IDLE. The conditions so->tx.state != ISOTP_IDLE and wq_has_sleeper(&so->wait) can not protect tx buffer from being accessed by multiple tx processes. We can use cmpxchg() to try to modify tx.state to ISOTP_SENDING firstly. If the modification of the previous process succeed, the later process must wait tx.state to ISOTP_IDLE firstly. Thus, we can ensure tx buffer is accessed by only one process at the same time. And we should also restore the original tx.state at the subsequent error processes. Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Signed-off-by: Ziyang Xuan Acked-by: Oliver Hartkopp --- net/can/isotp.c | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 2ac29c2b2ca6..d1f54273c0bb 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -121,7 +121,7 @@ enum { struct tpcon { int idx; int len; - u8 state; + u32 state; u8 bs; u8 sn; u8 ll_dl; @@ -848,6 +848,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) { struct sock *sk = sock->sk; struct isotp_sock *so = isotp_sk(sk); + u32 old_state = so->tx.state; struct sk_buff *skb; struct net_device *dev; struct canfd_frame *cf; @@ -860,47 +861,55 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) return -EADDRNOTAVAIL; /* we do not support multiple buffers - for now */ - if (so->tx.state != ISOTP_IDLE || wq_has_sleeper(&so->wait)) { - if (msg->msg_flags & MSG_DONTWAIT) - return -EAGAIN; + if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE || + wq_has_sleeper(&so->wait)) { + if (msg->msg_flags & MSG_DONTWAIT) { + err = -EAGAIN; + goto err_out; + } /* wait for complete transmission of current pdu */ err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); if (err) - return err; + goto err_out; } - if (!size || size > MAX_MSG_LENGTH) - return -EINVAL; + if (!size || size > MAX_MSG_LENGTH) { + err = -EINVAL; + goto err_out; + } /* take care of a potential SF_DL ESC offset for TX_DL > 8 */ off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0; /* does the given data fit into a single frame for SF_BROADCAST? */ if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) && - (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) - return -EINVAL; + (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) { + err = -EINVAL; + goto err_out; + } err = memcpy_from_msg(so->tx.buf, msg, size); if (err < 0) - return err; + goto err_out; dev = dev_get_by_index(sock_net(sk), so->ifindex); - if (!dev) - return -ENXIO; + if (!dev) { + err = -ENXIO; + goto err_out; + } skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv), msg->msg_flags & MSG_DONTWAIT, &err); if (!skb) { dev_put(dev); - return err; + goto err_out; } can_skb_reserve(skb); can_skb_prv(skb)->ifindex = dev->ifindex; can_skb_prv(skb)->skbcnt = 0; - so->tx.state = ISOTP_SENDING; so->tx.len = size; so->tx.idx = 0; @@ -956,7 +965,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) if (err) { pr_notice_once("can-isotp: %s: can_send_ret %pe\n", __func__, ERR_PTR(err)); - return err; + goto err_out; } if (wait_tx_done) { @@ -965,6 +974,13 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) } return size; + +err_out: + so->tx.state = old_state; + if (so->tx.state == ISOTP_IDLE) + wake_up_interruptible(&so->wait); + + return err; } static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,