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=-5.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,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 90FF4C65C22 for ; Fri, 2 Nov 2018 18:55:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 563C52084C for ; Fri, 2 Nov 2018 18:55:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="S1k3NdGZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 563C52084C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731524AbeKCEEI (ORCPT ); Sat, 3 Nov 2018 00:04:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:60172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726051AbeKCEEH (ORCPT ); Sat, 3 Nov 2018 00:04:07 -0400 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 2000C20848; Fri, 2 Nov 2018 18:55:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541184951; bh=6vFBngH1gqCzEZecaKEruQNFHBZ/Lok5hkQOI4KPUeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S1k3NdGZFxySRTKtry2oezhlPlTCUqg//VbUnW/Ac8Mza3MIMH7YzmCneSekHnMH/ G2ZlkLqw0Gs67qdhlAa2H/ogPo8hFW3fKVFU0hs+EhtV0a9eHtZ8d3c/CnE5C1umbp mTv+SZcP3DyHri3ACgbmMaJaZQdKiB0Rl1uPQgJI= 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" Subject: [PATCH 4.14 138/143] net: fix pskb_trim_rcsum_slow() with odd trim offset Date: Fri, 2 Nov 2018 19:35:23 +0100 Message-Id: <20181102182908.759651111@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181102182857.064326086@linuxfoundation.org> References: <20181102182857.064326086@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dimitris Michailidis [ Upstream commit d55bef5059dd057bd077155375c581b49d25be7e ] 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: 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 @@ -1843,8 +1843,9 @@ 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); }