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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 50B13C10F11 for ; Mon, 22 Apr 2019 17:28:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 203FC214AE for ; Mon, 22 Apr 2019 17:28:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="Sjg8klS9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727977AbfDVR2F (ORCPT ); Mon, 22 Apr 2019 13:28:05 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:39916 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726587AbfDVR2E (ORCPT ); Mon, 22 Apr 2019 13:28:04 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x3MHIXa2009292 for ; Mon, 22 Apr 2019 10:28:03 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=facebook; bh=ggkFPjU/Ne5UtSggqEaeg9mpDeASwYIDmOn8efG8i/Q=; b=Sjg8klS96z95lPkfZvb1uVAu9t+BpLLT5PMA0enSq0u2AKGnYpFqGk/bG09Z96FE8o44 gUyfHeXwy9oejNED2421021fUwQqCNNummPpRS+413+6H5kAgkj+ZkIuiUIvacjmrndL xroJaemAWIG6e2fU3IHYMKnKD3op8evvbUM= Received: from maileast.thefacebook.com ([199.201.65.23]) by m0001303.ppops.net with ESMTP id 2ryy3cqaf2-9 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Mon, 22 Apr 2019 10:28:03 -0700 Received: from mx-out.facebook.com (2620:10d:c0a1:3::13) by mail.thefacebook.com (2620:10d:c021:18::171) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Mon, 22 Apr 2019 10:27:57 -0700 Received: by devvm24792.prn1.facebook.com (Postfix, from userid 150176) id DFEF413A2728A; Mon, 22 Apr 2019 10:27:56 -0700 (PDT) Smtp-Origin-Hostprefix: devvm From: Tao Ren Smtp-Origin-Hostname: devvm24792.prn1.facebook.com To: Samuel Mendoza-Jonas , "David S . Miller" , , , Joel Stanley , Andrew Jeffery , CC: Tao Ren Smtp-Origin-Cluster: prn1c35 Subject: [PATCH net] net/ncsi: handle overflow when incrementing mac address Date: Mon, 22 Apr 2019 10:27:54 -0700 Message-ID: <20190422172754.1011894-1-taoren@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-22_01:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Previously BMC's MAC address is calculated by simply adding 1 to the last byte of network controller's MAC address, and it produces incorrect result when network controller's MAC address ends with 0xFF. The problem is fixed by detecting integer overflow when incrementing MAC address and adding the carry bit (if any) to the next/left bytes of the MAC address. Signed-off-by: Tao Ren --- net/ncsi/ncsi-rsp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/ncsi/ncsi-rsp.c b/net/ncsi/ncsi-rsp.c index dc07fcc7938e..eb42bbdb7501 100644 --- a/net/ncsi/ncsi-rsp.c +++ b/net/ncsi/ncsi-rsp.c @@ -658,7 +658,8 @@ static int ncsi_rsp_handler_oem_bcm_gma(struct ncsi_request *nr) const struct net_device_ops *ops = ndev->netdev_ops; struct ncsi_rsp_oem_pkt *rsp; struct sockaddr saddr; - int ret = 0; + int ret, offset; + u16 carry = 1; /* Get the response header */ rsp = (struct ncsi_rsp_oem_pkt *)skb_network_header(nr->rsp); @@ -667,7 +668,12 @@ static int ncsi_rsp_handler_oem_bcm_gma(struct ncsi_request *nr) ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE; memcpy(saddr.sa_data, &rsp->data[BCM_MAC_ADDR_OFFSET], ETH_ALEN); /* Increase mac address by 1 for BMC's address */ - saddr.sa_data[ETH_ALEN - 1]++; + offset = ETH_ALEN - 1; + do { + carry += (u8)saddr.sa_data[offset]; + saddr.sa_data[offset] = (char)carry; + carry = carry >> 8; + } while (carry != 0 && --offset >= 0); ret = ops->ndo_set_mac_address(ndev, &saddr); if (ret < 0) netdev_warn(ndev, "NCSI: 'Writing mac address to device failed\n"); -- 2.17.1