From patchwork Wed Mar 16 20:47:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 12783182 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52666C433F5 for ; Wed, 16 Mar 2022 20:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358041AbiCPUut (ORCPT ); Wed, 16 Mar 2022 16:50:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242606AbiCPUur (ORCPT ); Wed, 16 Mar 2022 16:50:47 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F78239141 for ; Wed, 16 Mar 2022 13:49:32 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nUaaI-0003pv-QV for netdev@vger.kernel.org; Wed, 16 Mar 2022 21:49:30 +0100 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 0AAA64CBA4 for ; Wed, 16 Mar 2022 20:47:12 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 9D1664CB6C; Wed, 16 Mar 2022 20:47:11 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 09d47ba5; Wed, 16 Mar 2022 20:47:11 +0000 (UTC) From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, kernel@pengutronix.de, Oliver Hartkopp , Derek Will , Marc Kleine-Budde Subject: [PATCH net-next 3/5] can: isotp: support MSG_TRUNC flag when reading from socket Date: Wed, 16 Mar 2022 21:47:08 +0100 Message-Id: <20220316204710.716341-4-mkl@pengutronix.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220316204710.716341-1-mkl@pengutronix.de> References: <20220316204710.716341-1-mkl@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Oliver Hartkopp When providing the MSG_TRUNC flag via recvmsg() syscall the return value provides the real length of the packet or datagram, even when it was longer than the passed buffer. Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Link: https://github.com/linux-can/can-utils/issues/347#issuecomment-1065932671 Link: https://lore.kernel.org/all/20220316164258.54155-3-socketcan@hartkopp.net Suggested-by: Derek Will Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 6b6c82206c30..f6f8ba1f816d 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1047,29 +1047,28 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, struct sock *sk = sock->sk; struct sk_buff *skb; struct isotp_sock *so = isotp_sk(sk); - int err = 0; - int noblock; + int noblock = flags & MSG_DONTWAIT; + int ret = 0; - noblock = flags & MSG_DONTWAIT; - flags &= ~MSG_DONTWAIT; + if (flags & ~(MSG_DONTWAIT | MSG_TRUNC)) + return -EINVAL; if (!so->bound) return -EADDRNOTAVAIL; - skb = skb_recv_datagram(sk, flags, noblock, &err); + flags &= ~MSG_DONTWAIT; + skb = skb_recv_datagram(sk, flags, noblock, &ret); if (!skb) - return err; + return ret; if (size < skb->len) msg->msg_flags |= MSG_TRUNC; else size = skb->len; - err = memcpy_to_msg(msg, skb->data, size); - if (err < 0) { - skb_free_datagram(sk, skb); - return err; - } + ret = memcpy_to_msg(msg, skb->data, size); + if (ret < 0) + goto out_err; sock_recv_timestamp(msg, sk, skb); @@ -1079,9 +1078,13 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, memcpy(msg->msg_name, skb->cb, msg->msg_namelen); } + /* set length of return value */ + ret = (flags & MSG_TRUNC) ? skb->len : size; + +out_err: skb_free_datagram(sk, skb); - return size; + return ret; } static int isotp_release(struct socket *sock)