From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162550Ab2GLXDm (ORCPT ); Thu, 12 Jul 2012 19:03:42 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:46543 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162530Ab2GLXDd (ORCPT ); Thu, 12 Jul 2012 19:03:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Bogdan Hamciuc , Eric Dumazet , Herbert Xu , Neil Horman , Cong Wang , "David S. Miller" Subject: [ 15/68] netpoll: fix netpoll_send_udp() bugs Date: Thu, 12 Jul 2012 16:01:49 -0700 Message-Id: <20120712175036.778252084@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712175035.530652872@linuxfoundation.org> References: <20120712175057.GA9917@kroah.com> <20120712175035.530652872@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 954fba0274058d27c7c07b5ea07c41b3b7477894 ] Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() : "skb->len += len;" instead of "skb_put(skb, len);" Meaning that _if_ a network driver needs to call skb_realloc_headroom(), only packet headers would be copied, leaving garbage in the payload. However the skb_realloc_headroom() must be avoided as much as possible since it requires memory and netpoll tries hard to work even if memory is exhausted (using a pool of preallocated skbs) It appears netpoll_send_udp() reserved 16 bytes for the ethernet header, which happens to work for typicall drivers but not all. Right thing is to use LL_RESERVED_SPACE(dev) (And also add dev->needed_tailroom of tailroom) This patch combines both fixes. Many thanks to Bogdan for raising this issue. Reported-by: Bogdan Hamciuc Signed-off-by: Eric Dumazet Tested-by: Bogdan Hamciuc Cc: Herbert Xu Cc: Neil Horman Reviewed-by: Neil Horman Reviewed-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/netpoll.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -357,22 +357,23 @@ EXPORT_SYMBOL(netpoll_send_skb_on_dev); void netpoll_send_udp(struct netpoll *np, const char *msg, int len) { - int total_len, eth_len, ip_len, udp_len; + int total_len, ip_len, udp_len; struct sk_buff *skb; struct udphdr *udph; struct iphdr *iph; struct ethhdr *eth; udp_len = len + sizeof(*udph); - ip_len = eth_len = udp_len + sizeof(*iph); - total_len = eth_len + ETH_HLEN + NET_IP_ALIGN; + ip_len = udp_len + sizeof(*iph); + total_len = ip_len + LL_RESERVED_SPACE(np->dev); - skb = find_skb(np, total_len, total_len - len); + skb = find_skb(np, total_len + np->dev->needed_tailroom, + total_len - len); if (!skb) return; skb_copy_to_linear_data(skb, msg, len); - skb->len += len; + skb_put(skb, len); skb_push(skb, sizeof(*udph)); skb_reset_transport_header(skb);