From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755952AbdGSRrD (ORCPT ); Wed, 19 Jul 2017 13:47:03 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34941 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755930AbdGSRrB (ORCPT ); Wed, 19 Jul 2017 13:47:01 -0400 From: Colin King To: Andy Gospodarek , netdev@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] net: tehuti: don't process data if it has not been copied from userspace Date: Wed, 19 Jul 2017 18:46:59 +0100 Message-Id: <20170719174659.22646-1-colin.king@canonical.com> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King The array data is only populated with valid information from userspace if cmd != SIOCDEVPRIVATE, other cases the array contains garbage on the stack. The subsequent switch statement acts on a subcommand in data[0] which could be any garbage value if cmd is SIOCDEVPRIVATE which seems incorrect to me. Instead, just return EOPNOTSUPP for the case where cmd == SIOCDEVPRIVATE to avoid this issue. As a side note, I suspect that the original intention of the code was for this ioctl to work just for cmd == SIOCDEVPRIVATE (and the current logic is reversed). However, I don't wont to change the current semantics in case any userspace code relies on this existing behaviour. Detected by CoverityScan, CID#139647 ("Uninitialized scalar variable") Signed-off-by: Colin Ian King --- drivers/net/ethernet/tehuti/tehuti.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/tehuti/tehuti.c b/drivers/net/ethernet/tehuti/tehuti.c index 711fbbbc4b1f..163d8d16bc24 100644 --- a/drivers/net/ethernet/tehuti/tehuti.c +++ b/drivers/net/ethernet/tehuti/tehuti.c @@ -654,6 +654,8 @@ static int bdx_ioctl_priv(struct net_device *ndev, struct ifreq *ifr, int cmd) RET(-EFAULT); } DBG("%d 0x%x 0x%x\n", data[0], data[1], data[2]); + } else { + return -EOPNOTSUPP; } if (!capable(CAP_SYS_RAWIO)) -- 2.11.0