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=-8.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 33CFAC31E49 for ; Wed, 19 Jun 2019 14:30:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BF8E2166E for ; Wed, 19 Jun 2019 14:30:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729325AbfFSOav (ORCPT ); Wed, 19 Jun 2019 10:30:51 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56887 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725899AbfFSOav (ORCPT ); Wed, 19 Jun 2019 10:30:51 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1hdbbp-0005sO-5S; Wed, 19 Jun 2019 14:30:45 +0000 From: Colin King To: Jeff Kirsher , "David S . Miller" , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][net-next] iavf: fix dereference of null rx_buffer pointer Date: Wed, 19 Jun 2019 15:30:44 +0100 Message-Id: <20190619143044.10259-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Colin Ian King A recent commit efa14c3985828d ("iavf: allow null RX descriptors") added a null pointer sanity check on rx_buffer, however, rx_buffer is being dereferenced before that check, which implies a null pointer dereference bug can potentially occur. Fix this by only dereferencing rx_buffer until after the null pointer check. Addresses-Coverity: ("Dereference before null check") Signed-off-by: Colin Ian King --- drivers/net/ethernet/intel/iavf/iavf_txrx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c index 1cde1601bc32..0cca1b589b56 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c +++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c @@ -1296,7 +1296,7 @@ static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring, struct iavf_rx_buffer *rx_buffer, unsigned int size) { - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; + void *va; #if (PAGE_SIZE < 8192) unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2; #else @@ -1308,6 +1308,7 @@ static struct sk_buff *iavf_construct_skb(struct iavf_ring *rx_ring, if (!rx_buffer) return NULL; /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; prefetch(va); #if L1_CACHE_BYTES < 128 prefetch(va + L1_CACHE_BYTES); @@ -1362,7 +1363,7 @@ static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring, struct iavf_rx_buffer *rx_buffer, unsigned int size) { - void *va = page_address(rx_buffer->page) + rx_buffer->page_offset; + void *va; #if (PAGE_SIZE < 8192) unsigned int truesize = iavf_rx_pg_size(rx_ring) / 2; #else @@ -1374,6 +1375,7 @@ static struct sk_buff *iavf_build_skb(struct iavf_ring *rx_ring, if (!rx_buffer) return NULL; /* prefetch first cache line of first page */ + va = page_address(rx_buffer->page) + rx_buffer->page_offset; prefetch(va); #if L1_CACHE_BYTES < 128 prefetch(va + L1_CACHE_BYTES); -- 2.20.1