Return-path: Received: from mail-lf0-f66.google.com ([209.85.215.66]:40962 "EHLO mail-lf0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752770AbeAFKBS (ORCPT ); Sat, 6 Jan 2018 05:01:18 -0500 Received: by mail-lf0-f66.google.com with SMTP id h137so7501085lfe.8 for ; Sat, 06 Jan 2018 02:01:17 -0800 (PST) Subject: Re: [PATCH 08/18] carl9170: prevent bounds-check bypass via speculative execution To: Dan Williams , linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, peterz@infradead.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, Elena Reshetova , gregkh@linuxfoundation.org, Christian Lamparter , tglx@linutronix.de, torvalds@linux-foundation.org, Kalle Valo , alan@linux.intel.com References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> <151520103755.32271.6819511294540882298.stgit@dwillia2-desk3.amr.corp.intel.com> From: Sergei Shtylyov Message-ID: <113c7f80-265b-4da2-3eba-727c8f64a2b0@cogentembedded.com> (sfid-20180106_110144_885868_FC862CBE) Date: Sat, 6 Jan 2018 13:01:15 +0300 MIME-Version: 1.0 In-Reply-To: <151520103755.32271.6819511294540882298.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Hello! On 1/6/2018 4:10 AM, Dan Williams wrote: > Static analysis reports that 'queue' may be a user controlled value that > is used as a data dependency to read from the 'ar9170_qmap' array. In > order to avoid potential leaks of kernel memory values, block > speculative execution of the instruction stream that could issue reads > based on an invalid result of 'ar9170_qmap[queue]'. In this case the > value of 'ar9170_qmap[queue]' is immediately reused as an index to the > 'ar->edcf' array. > > Based on an original patch by Elena Reshetova. > > Cc: Christian Lamparter > Cc: Kalle Valo > Cc: linux-wireless@vger.kernel.org > Cc: netdev@vger.kernel.org > Signed-off-by: Elena Reshetova > Signed-off-by: Dan Williams > --- > drivers/net/wireless/ath/carl9170/main.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c > index 988c8857d78c..0ff34cbe2b62 100644 > --- a/drivers/net/wireless/ath/carl9170/main.c > +++ b/drivers/net/wireless/ath/carl9170/main.c > @@ -41,6 +41,7 @@ > #include > #include > #include > +#include > #include > #include > #include "hw.h" > @@ -1384,11 +1385,12 @@ static int carl9170_op_conf_tx(struct ieee80211_hw *hw, > const struct ieee80211_tx_queue_params *param) > { > struct ar9170 *ar = hw->priv; > + const u8 *elem; > int ret; > > mutex_lock(&ar->mutex); > - if (queue < ar->hw->queues) { > - memcpy(&ar->edcf[ar9170_qmap[queue]], param, sizeof(*param)); > + if ((elem = nospec_array_ptr(ar9170_qmap, queue, ar->hw->queues))) { I bet this causes checkpatch.pl to complain. I don't see a dire need to upset it here, the assignment may well precede *if*... > + memcpy(&ar->edcf[*elem], param, sizeof(*param)); > ret = carl9170_set_qos(ar); > } else { > ret = -EINVAL; > MBR, Sergei