From patchwork Sun Sep 26 11:01:42 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: 12518247 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 E07E6C433FE for ; Sun, 26 Sep 2021 11:02:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C487460F0F for ; Sun, 26 Sep 2021 11:02:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230505AbhIZLEX (ORCPT ); Sun, 26 Sep 2021 07:04:23 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:23957 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230498AbhIZLES (ORCPT ); Sun, 26 Sep 2021 07:04:18 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HHN6V1xMszY4QF; Sun, 26 Sep 2021 18:58:26 +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; Sun, 26 Sep 2021 19:02:40 +0800 From: Ziyang Xuan To: CC: , , , , , Subject: [PATCH net 2/2] can: isotp: fix tx buffer concurrent access in isotp_sendmsg() Date: Sun, 26 Sep 2021 19:01:42 +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: dggems706-chm.china.huawei.com (10.3.19.183) 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 Reported-by: kernel test robot --- net/can/isotp.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 2ac29c2b2ca6..506e16623c84 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -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); + u8 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,