From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D0BCC433F5 for ; Mon, 14 Feb 2022 10:02:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345253AbiBNKBc (ORCPT ); Mon, 14 Feb 2022 05:01:32 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:45284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344153AbiBNJ5K (ORCPT ); Mon, 14 Feb 2022 04:57:10 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C458F6A034; Mon, 14 Feb 2022 01:45:53 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5F37261237; Mon, 14 Feb 2022 09:45:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D21DC340E9; Mon, 14 Feb 2022 09:45:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644831952; bh=pgZjIPO/xPpvA04zri388RaooRNpi1eK/Oi2BDZbWD4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KfNN5kNary2EQJsph11E8JHW6H3dpJiJi5L17j/HPZCZ30zwKj0FFGKEm0jrQ3laz PDPgeNRPUD5iFtL8uiFuvQJYqurQEAkZUMQVGC8qRbtd6CQ4K9cjekheYLqboKz22m 3kwV5f1UlQCFvm7GT1+DwHujlBO4WcA6MinjP2RQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ziyang Xuan , Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH 5.15 009/172] can: isotp: fix error path in isotp_sendmsg() to unlock wait queue Date: Mon, 14 Feb 2022 10:24:27 +0100 Message-Id: <20220214092506.675536224@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220214092506.354292783@linuxfoundation.org> References: <20220214092506.354292783@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oliver Hartkopp commit 8375dfac4f683e1b2c5956d919d36aeedad46699 upstream. Commit 43a08c3bdac4 ("can: isotp: isotp_sendmsg(): fix TX buffer concurrent access in isotp_sendmsg()") introduced a new locking scheme that may render the userspace application in a locking state when an error is detected. This issue shows up under high load on simultaneously running isotp channels with identical configuration which is against the ISO specification and therefore breaks any reasonable PDU communication anyway. Fixes: 43a08c3bdac4 ("can: isotp: isotp_sendmsg(): fix TX buffer concurrent access in isotp_sendmsg()") Link: https://lore.kernel.org/all/20220209073601.25728-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org Cc: Ziyang Xuan Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/isotp.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -887,7 +887,7 @@ static int isotp_sendmsg(struct socket * if (!size || size > MAX_MSG_LENGTH) { err = -EINVAL; - goto err_out; + goto err_out_drop; } /* take care of a potential SF_DL ESC offset for TX_DL > 8 */ @@ -897,24 +897,24 @@ static int isotp_sendmsg(struct socket * if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) && (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) { err = -EINVAL; - goto err_out; + goto err_out_drop; } err = memcpy_from_msg(so->tx.buf, msg, size); if (err < 0) - goto err_out; + goto err_out_drop; dev = dev_get_by_index(sock_net(sk), so->ifindex); if (!dev) { err = -ENXIO; - goto err_out; + goto err_out_drop; } 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); - goto err_out; + goto err_out_drop; } can_skb_reserve(skb); @@ -976,7 +976,7 @@ static int isotp_sendmsg(struct socket * if (err) { pr_notice_once("can-isotp: %s: can_send_ret %pe\n", __func__, ERR_PTR(err)); - goto err_out; + goto err_out_drop; } if (wait_tx_done) { @@ -989,6 +989,9 @@ static int isotp_sendmsg(struct socket * return size; +err_out_drop: + /* drop this PDU and unlock a potential wait queue */ + old_state = ISOTP_IDLE; err_out: so->tx.state = old_state; if (so->tx.state == ISOTP_IDLE)