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=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 DB429C433E1 for ; Thu, 13 Aug 2020 18:17:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FCE420791 for ; Thu, 13 Aug 2020 18:17:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Sfl2o3Iu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726557AbgHMSRP (ORCPT ); Thu, 13 Aug 2020 14:17:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726167AbgHMSRO (ORCPT ); Thu, 13 Aug 2020 14:17:14 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B06CBC061757; Thu, 13 Aug 2020 11:17:14 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id 74so3203956pfx.13; Thu, 13 Aug 2020 11:17:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=6J6/ZU0XbO+1z0IeOrxIOq56pykTQVgam02T5CujhsY=; b=Sfl2o3IupApdQfJYRrhDbZz83oL0Faj84cpfTA5gWAqGN9YwQD5RH2i4FnYIphPeaM X8p0vHWcaT12XRonncClBL0QtnF2ElVeUHc0qdWV/nlfiOMSRNd+e0OeM/1c63Gl7kdn p4SGfcO14Se72YcMESVTXtgSRQ019N9q1SmTn+Hj61TPrP69fHUJzkKZJLs2NH4yoOMd lx3ujMG8hTKyiIFK3K15aRIWsls80wjLjvB63r77l4bOWz9OC2mcmeYgcd2lYLxZWrF3 64/d/mqIihhZm8okdlmWUJqr5q4OuNzCop/snlEs1iZFvCITFs05yfsZ2uVq3LIurAN2 J61A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=6J6/ZU0XbO+1z0IeOrxIOq56pykTQVgam02T5CujhsY=; b=SS13T8T+bldFenImW2BcLPW7s3of68PUuWGHC1vzel46kc3ioi7IjJRfGQi00s07pJ Z2xIYRMfXjRrShK6YngFdcMCpy3Yezad1NAc5KY+fKph0fJDJFYErPEmyHFkFgEcJiAp rxwQ/AzVqYAuERTRjB2432JuNYwb6tV6DCvujQsRJUpC+HKe9/Mu6QaqT4LFvHqeRa+Y lTl8i85E7xBc/2fXXHuh/H/G69rHjVfdvGhQseelTtntTqnh7uoNVB8S3vxvFCFXT9Pd 6TitP8f29T86qT9Otd64GrL3J5RHM+ppRF+4wItoBd1Gvrphv7UV3McLVACNCRzHm8Wu T/Yw== X-Gm-Message-State: AOAM530gBYG1Yv2GACsAPWv8MXqm8IFCRdtcoFvWuncgq74bT+KTftJH vYRl6+loHWLPUQv2L2Gspco= X-Google-Smtp-Source: ABdhPJyqwPenOAaISNvhIDlThUwNOmobc4MGRd6N09vIHLbyOdOWHKSNMlh3KmCdUWMOJq3Gh8aiTA== X-Received: by 2002:a63:ef46:: with SMTP id c6mr4740468pgk.96.1597342633192; Thu, 13 Aug 2020 11:17:13 -0700 (PDT) Received: from shane-XPS-13-9380.hsd1.ca.comcast.net (c-73-189-11-147.hsd1.ca.comcast.net. [73.189.11.147]) by smtp.gmail.com with ESMTPSA id f6sm6169684pje.16.2020.08.13.11.17.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Aug 2020 11:17:12 -0700 (PDT) From: Xie He To: "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-x25@vger.kernel.org Cc: Xie He , Willem de Bruijn , Martin Schiller , Andrew Hendry Subject: [PATCH net] drivers/net/wan/hdlc_x25: Added needed_headroom and a skb->len check Date: Thu, 13 Aug 2020 11:17:04 -0700 Message-Id: <20200813181704.62694-1-xie.he.0141@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 dfc16770458d..386ed2aa31fd 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 f70336bb6f52..f52b9fed0593 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