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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 95388C282C2 for ; Thu, 7 Feb 2019 11:44:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F04E21907 for ; Thu, 7 Feb 2019 11:44:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549539845; bh=C28zICoe2dVahHfh/YL/ZNq/RIFwpoHWQakcrismqKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=V0qDwSAOnr7AbHubuncMkumPMxlrD+owlzu6ZoiREHclRpsjTy5LY+PpobvlsOaHz LcV9FAWHe2eza0XH79hKKQPtC+z8NLw8Ul482lzuw/p3yotBvjkc9J+CgBEdwNcOp/ y7aNZ1dmzoc/+AvzC8iJlvLh8kH7TrYTZVD6FaoI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727668AbfBGLoD (ORCPT ); Thu, 7 Feb 2019 06:44:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:34552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727652AbfBGLn7 (ORCPT ); Thu, 7 Feb 2019 06:43:59 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B63CF21928; Thu, 7 Feb 2019 11:43:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549539839; bh=C28zICoe2dVahHfh/YL/ZNq/RIFwpoHWQakcrismqKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pVZVc4GNd83JTxZj+6Evx3wEmS+q0dv1qTiE+ED89t97R96fjzSob9av9un9FG2oB O+GsPBpQVAI9FHZvrQve7etaTUSZs/6kOQrJUATOEMkJZ1Whg13MoJ12SszKcF40AD dIfma2Dd+B/nAS17FS5EcLUdi2KI10yqM1b960+Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dimitris Michailidis , Eric Dumazet , "David S. Miller" , Ben Hutchings Subject: [PATCH 4.4 32/34] net: fix pskb_trim_rcsum_slow() with odd trim offset Date: Thu, 7 Feb 2019 12:42:14 +0100 Message-Id: <20190207113026.792795469@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190207113025.552605181@linuxfoundation.org> References: <20190207113025.552605181@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dimitris Michailidis commit d55bef5059dd057bd077155375c581b49d25be7e upstream. We've been getting checksum errors involving small UDP packets, usually 59B packets with 1 extra non-zero padding byte. netdev_rx_csum_fault() has been complaining that HW is providing bad checksums. Turns out the problem is in pskb_trim_rcsum_slow(), introduced in commit 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends"). The source of the problem is that when the bytes we are trimming start at an odd address, as in the case of the 1 padding byte above, skb_checksum() returns a byte-swapped value. We cannot just combine this with skb->csum using csum_sub(). We need to use csum_block_sub() here that takes into account the parity of the start address and handles the swapping. Matches existing code in __skb_postpull_rcsum() and esp_remove_trailer(). Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends") Signed-off-by: Dimitris Michailidis Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1509,8 +1509,9 @@ int pskb_trim_rcsum_slow(struct sk_buff if (skb->ip_summed == CHECKSUM_COMPLETE) { int delta = skb->len - len; - skb->csum = csum_sub(skb->csum, - skb_checksum(skb, len, delta, 0)); + skb->csum = csum_block_sub(skb->csum, + skb_checksum(skb, len, delta, 0), + len); } return __pskb_trim(skb, len); }