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 X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44C0FC433E1 for ; Mon, 24 Aug 2020 17:22:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D0EA20738 for ; Mon, 24 Aug 2020 17:22:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598289778; bh=MCxPakGL9ABd29OvlEbGaratiOtRqPYeKeb2GiLmDas=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZS8qgZZyu54rECKUl3iiYMfQwtE42YSGQVCjGBAbsMW32To2lyvp4u2hjZqMrO3Ob WBcjdKf8Yin/SNfnj3bHMAPQCFAYpMq+mKVyGIoq4xIsVI/kUyo9IhX2NGKiSsDSSe oQGPPfTDv846omkjyzr1R8N6LiKVL6rRZ1TAiTZg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728289AbgHXRWy (ORCPT ); Mon, 24 Aug 2020 13:22:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:40220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727937AbgHXQfs (ORCPT ); Mon, 24 Aug 2020 12:35:48 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0C76022C9F; Mon, 24 Aug 2020 16:35:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598286948; bh=MCxPakGL9ABd29OvlEbGaratiOtRqPYeKeb2GiLmDas=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Aiyy2/O8nlIvYRTnXuz3JB4k8JaR2i/IMtJIxYoUWcKqV2Kk88ksQZHku/zEpGJa6 ARXFYneRGr9LLan5fsDpTy0Gsdg0MYZNGEdverShA++jpUDVywuVlfAthL3oUGGwLx c9JhX+q8/i9N5UV31IEQaThoEI5izwhuMfE3t8iE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xie He , Willem de Bruijn , Martin Schiller , Andrew Hendry , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.8 32/63] drivers/net/wan/hdlc_x25: Added needed_headroom and a skb->len check Date: Mon, 24 Aug 2020 12:34:32 -0400 Message-Id: <20200824163504.605538-32-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200824163504.605538-1-sashal@kernel.org> References: <20200824163504.605538-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xie He [ Upstream commit 77b981c82c1df7c7ad32a046f17f007450b46954 ] 1. Added a skb->len check This driver expects upper layers to include a pseudo header of 1 byte when passing down a skb for transmission. This driver will read this 1-byte header. This patch added a skb->len check before reading the header to make sure the header exists. 2. Added needed_headroom and set hard_header_len to 0 When this driver transmits data, first this driver will remove a pseudo header of 1 byte, then the lapb module will prepend the LAPB header of 2 or 3 bytes. So the value of needed_headroom in this driver should be 3 - 1. Because this driver has no header_ops, according to the logic of af_packet.c, the value of hard_header_len should be 0. Reason of setting needed_headroom and hard_header_len at this place: This driver is written using the API of the hdlc module, the hdlc module enables this driver (the protocol driver) to run on any hardware that has a driver (the hardware driver) written using the API of the hdlc module. Two other hdlc protocol drivers - hdlc_ppp and hdlc_raw_eth, also set things like hard_header_len at this place. In hdlc_ppp, it sets hard_header_len after attach_hdlc_protocol and before setting dev->type. In hdlc_raw_eth, it sets hard_header_len by calling ether_setup after attach_hdlc_protocol and after memcpy the settings. 3. Reset needed_headroom when detaching protocols (in hdlc.c) When detaching a protocol from a hardware device, the hdlc module will reset various parameters of the device (including hard_header_len) to the default values. We add needed_headroom here so that needed_headroom will also be reset. Cc: Willem de Bruijn Cc: Martin Schiller Cc: Andrew Hendry Signed-off-by: Xie He Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/wan/hdlc.c | 1 + drivers/net/wan/hdlc_x25.c | 17 ++++++++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c index dfc16770458d8..386ed2aa31fd9 100644 --- a/drivers/net/wan/hdlc.c +++ b/drivers/net/wan/hdlc.c @@ -230,6 +230,7 @@ static void hdlc_setup_dev(struct net_device *dev) dev->max_mtu = HDLC_MAX_MTU; dev->type = ARPHRD_RAWHDLC; dev->hard_header_len = 16; + dev->needed_headroom = 0; dev->addr_len = 0; dev->header_ops = &hdlc_null_ops; } diff --git a/drivers/net/wan/hdlc_x25.c b/drivers/net/wan/hdlc_x25.c index f70336bb6f524..f52b9fed05931 100644 --- a/drivers/net/wan/hdlc_x25.c +++ b/drivers/net/wan/hdlc_x25.c @@ -107,8 +107,14 @@ static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev) { int result; + /* There should be a pseudo header of 1 byte added by upper layers. + * Check to make sure it is there before reading it. + */ + if (skb->len < 1) { + kfree_skb(skb); + return NETDEV_TX_OK; + } - /* X.25 to LAPB */ switch (skb->data[0]) { case X25_IFACE_DATA: /* Data to be transmitted */ skb_pull(skb, 1); @@ -294,6 +300,15 @@ static int x25_ioctl(struct net_device *dev, struct ifreq *ifr) return result; memcpy(&state(hdlc)->settings, &new_settings, size); + + /* There's no header_ops so hard_header_len should be 0. */ + dev->hard_header_len = 0; + /* When transmitting data: + * first we'll remove a pseudo header of 1 byte, + * then we'll prepend an LAPB header of at most 3 bytes. + */ + dev->needed_headroom = 3 - 1; + dev->type = ARPHRD_X25; call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev); netif_dormant_off(dev); -- 2.25.1