From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751512AbeECTCn (ORCPT ); Thu, 3 May 2018 15:02:43 -0400 Received: from gateway20.websitewelcome.com ([192.185.61.9]:40398 "EHLO gateway20.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751181AbeECTCm (ORCPT ); Thu, 3 May 2018 15:02:42 -0400 X-Authority-Reason: nr=8 Date: Thu, 3 May 2018 13:17:12 -0500 From: "Gustavo A. R. Silva" To: Chas Williams <3chas3@gmail.com>, "David S. Miller" Cc: linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] atm: zatm: Fix potential Spectre v1 Message-ID: <20180503181712.GA7443@embeddedor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 187.172.56.86 X-Source-L: No X-Exim-ID: 1fEIn4-003nx7-7S X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [187.172.56.86]:42960 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 5 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pool can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/atm/zatm.c:1462 zatm_ioctl() warn: potential spectre issue 'zatm_dev->pool_info' (local cap) Fix this by sanitizing pool before using it to index zatm_dev->pool_info Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva --- drivers/atm/zatm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/atm/zatm.c b/drivers/atm/zatm.c index 1ef67db..9c9a229 100644 --- a/drivers/atm/zatm.c +++ b/drivers/atm/zatm.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "uPD98401.h" #include "uPD98402.h" @@ -1458,6 +1459,8 @@ static int zatm_ioctl(struct atm_dev *dev,unsigned int cmd,void __user *arg) return -EFAULT; if (pool < 0 || pool > ZATM_LAST_POOL) return -EINVAL; + pool = array_index_nospec(pool, + ZATM_LAST_POOL + 1); spin_lock_irqsave(&zatm_dev->lock, flags); info = zatm_dev->pool_info[pool]; if (cmd == ZATM_GETPOOLZ) { -- 2.7.4