From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41325 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753950AbbJWRwJ (ORCPT ); Fri, 23 Oct 2015 13:52:09 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrew Vagin , Pravin B Shelar , "David S. Miller" Subject: [PATCH 3.14 06/25] skbuff: Fix skb checksum partial check. Date: Fri, 23 Oct 2015 10:45:47 -0700 Message-Id: <20151023174552.995989695@linuxfoundation.org> In-Reply-To: <20151023174552.800926510@linuxfoundation.org> References: <20151023174552.800926510@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pravin B Shelar [ Upstream commit 31b33dfb0a144469dd805514c9e63f4993729a48 ] Earlier patch 6ae459bda tried to detect void ckecksum partial skb by comparing pull length to checksum offset. But it does not work for all cases since checksum-offset depends on updates to skb->data. Following patch fixes it by validating checksum start offset after skb-data pointer is updated. Negative value of checksum offset start means there is no need to checksum. Fixes: 6ae459bda ("skbuff: Fix skb checksum flag on skb pull") Reported-by: Andrew Vagin Signed-off-by: Pravin B Shelar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/skbuff.h | 2 +- net/core/skbuff.c | 9 +++++---- 2 files changed, 6 insertions(+), 5 deletions(-) --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2348,7 +2348,7 @@ static inline void skb_postpull_rcsum(st if (skb->ip_summed == CHECKSUM_COMPLETE) skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0)); else if (skb->ip_summed == CHECKSUM_PARTIAL && - skb_checksum_start_offset(skb) <= len) + skb_checksum_start_offset(skb) < 0) skb->ip_summed = CHECKSUM_NONE; } --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2862,11 +2862,12 @@ EXPORT_SYMBOL(skb_append_datato_frags); */ unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) { + unsigned char *data = skb->data; + BUG_ON(len > skb->len); - skb->len -= len; - BUG_ON(skb->len < skb->data_len); - skb_postpull_rcsum(skb, skb->data, len); - return skb->data += len; + __skb_pull(skb, len); + skb_postpull_rcsum(skb, data, len); + return skb->data; } EXPORT_SYMBOL_GPL(skb_pull_rcsum);