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 6BB9EC433FE for ; Wed, 16 Mar 2022 16:43:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357424AbiCPQoh (ORCPT ); Wed, 16 Mar 2022 12:44:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355976AbiCPQog (ORCPT ); Wed, 16 Mar 2022 12:44:36 -0400 Received: from mo4-p00-ob.smtp.rzone.de (mo4-p00-ob.smtp.rzone.de [85.215.255.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A94715A06 for ; Wed, 16 Mar 2022 09:43:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1647448994; s=strato-dkim-0002; d=hartkopp.net; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=2u7Gud42Y+x/I1L8jYVL7BPOnWyINx4uiT2WavJMIs0=; b=WHF7XjSXm1sf7X6OGrhU4udbu8Ei/jqrh1aXGS0OoJMoNz+2tTc2VlJRz42QwavZfk 8gLuX7SmD2I9v+y+jXDGC5Usm4bjGMh9jLzkgPdGcFiNV8JlLaTzVPAP/voDyALtVcdp GRIWBv/YtPtf1Q9rviIFVYuB+TBA16AC6hFMyMeFjuyU7Rfmbn4cuGhHCb/ohePFOSDD av2ttRCqCu6VX+aPgIf6ANV6NVE5tsEJNt/9gm5npVLgGEAIC75X6SH/ensse7rMUD63 cr85sorxCBtFmxwzjrtup98iaxmsQ9yR8eqEh8gwBYEE3eQ0PajZoYAyXZqWcPhMCNU3 kTqQ== Authentication-Results: strato.com; dkim=none X-RZG-AUTH: ":P2MHfkW8eP4Mre39l357AZT/I7AY/7nT2yrDxb8mjGrp7owjzFK3JbFk1mS/xvEBL7X5sbo3UIh9IyLecSWJafUv+rx4" X-RZG-CLASS-ID: mo00 Received: from silver.lan by smtp.strato.de (RZmta 47.41.0 AUTH) with ESMTPSA id a046a1y2GGhE4CJ (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Wed, 16 Mar 2022 17:43:14 +0100 (CET) From: Oliver Hartkopp To: linux-can@vger.kernel.org Cc: Oliver Hartkopp , Derek Will Subject: [PATCH 3/3] can: isotp: support MSG_TRUNC flag when reading from socket Date: Wed, 16 Mar 2022 17:42:58 +0100 Message-Id: <20220316164258.54155-3-socketcan@hartkopp.net> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220316164258.54155-1-socketcan@hartkopp.net> References: <20220316164258.54155-1-socketcan@hartkopp.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org 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 Suggested-by: Derek Will Signed-off-by: Oliver Hartkopp --- 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 @@ -1045,45 +1045,48 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int flags) { 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); if (msg->msg_name) { __sockaddr_check_size(ISOTP_MIN_NAMELEN); msg->msg_namelen = ISOTP_MIN_NAMELEN; 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) { struct sock *sk = sock->sk; -- 2.30.2