Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754208Ab1ECRtb (ORCPT ); Tue, 3 May 2011 13:49:31 -0400 Received: from mail.solarflare.com ([216.237.3.220]:59805 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752856Ab1ECRt3 (ORCPT ); Tue, 3 May 2011 13:49:29 -0400 Subject: [PATCH net-next-2.6] ipheth: Properly distinguish length and alignment in URBs and skbs From: Ben Hutchings To: David Hill Cc: "L. Alberto" =?ISO-8859-1?Q?Gim=E9nez?= , "linux-kernel@vger.kernel.org" , "dgiagio@gmail.com" , "dborca@yahoo.com" , "davem@davemloft.net" , "pmcenery@gmail.com" , "open list:USB SUBSYSTEM" , "open list:NETWORKING DRIVERS" In-Reply-To: <710D4D6CE160654C87478D18385BB9971BE3FDCA46@MDC-MAIL-CMS01.ubisoft.org> References: <1304264799.2833.82.camel@localhost> <1304364912-15444-1-git-send-email-agimenez@sysvalve.es> <1304370274.2833.192.camel@localhost> <20110503165751.GA6566@bart.evergreen.loc> <710D4D6CE160654C87478D18385BB9971BE3FDCA46@MDC-MAIL-CMS01.ubisoft.org> Content-Type: text/plain; charset="UTF-8" Organization: Solarflare Communications Date: Tue, 03 May 2011 18:49:25 +0100 Message-ID: <1304444965.2873.11.camel@bwh-desktop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 (2.32.1-1.fc14) Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 03 May 2011 17:49:28.0774 (UTC) FILETIME=[732C1E60:01CC09BA] X-TM-AS-Product-Ver: SMEX-8.0.0.1181-6.500.1024-18110.005 X-TM-AS-Result: No--9.033900-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2344 Lines: 73 The USB protocol this driver implements appears to require 2 bytes of padding in front of each received packet. This used to be equal to the value of NET_IP_ALIGN on x86, so the driver abused that constant and mostly worked, but this is no longer the case. The driver also mixed up the URB and packet lengths, resulting in 2 bytes of junk at the end of the skb. Introduce a private constant for the 2 bytes of padding; fix this confusion and check for the under-length case. Signed-off-by: Ben Hutchings --- Compile-tested only, as I'm not cool enough for an iPhone either. This is applicable to net-next-2.6 or v2.6.38. Ben. drivers/net/usb/ipheth.c | 14 +++++++++----- 1 files changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c index 7d42f9a..81126ff 100644 --- a/drivers/net/usb/ipheth.c +++ b/drivers/net/usb/ipheth.c @@ -65,6 +65,7 @@ #define IPHETH_USBINTF_PROTO 1 #define IPHETH_BUF_SIZE 1516 +#define IPHETH_IP_ALIGN 2 /* padding at front of URB */ #define IPHETH_TX_TIMEOUT (5 * HZ) #define IPHETH_INTFNUM 2 @@ -202,18 +203,21 @@ static void ipheth_rcvbulk_callback(struct urb *urb) return; } - len = urb->actual_length; - buf = urb->transfer_buffer; + if (urb->actual_length <= IPHETH_IP_ALIGN) { + dev->net->stats.rx_length_errors++; + return; + } + len = urb->actual_length - IPHETH_IP_ALIGN; + buf = urb->transfer_buffer + IPHETH_IP_ALIGN; - skb = dev_alloc_skb(NET_IP_ALIGN + len); + skb = dev_alloc_skb(len); if (!skb) { err("%s: dev_alloc_skb: -ENOMEM", __func__); dev->net->stats.rx_dropped++; return; } - skb_reserve(skb, NET_IP_ALIGN); - memcpy(skb_put(skb, len), buf + NET_IP_ALIGN, len - NET_IP_ALIGN); + memcpy(skb_put(skb, len), buf, len); skb->dev = dev->net; skb->protocol = eth_type_trans(skb, dev->net); -- 1.7.4 -- Ben Hutchings, Senior Software Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/