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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 293D7C43219 for ; Sat, 27 Apr 2019 15:18:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 007BD206A3 for ; Sat, 27 Apr 2019 15:18:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728096AbfD0PSz (ORCPT ); Sat, 27 Apr 2019 11:18:55 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34234 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727683AbfD0PPi (ORCPT ); Sat, 27 Apr 2019 11:15:38 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hKP39-00014C-Vl; Sat, 27 Apr 2019 16:15:36 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hKP2i-0004SC-RT; Sat, 27 Apr 2019 16:15:08 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Gustavo A. R. Silva" , "Greg Kroah-Hartman" Date: Sat, 27 Apr 2019 16:13:09 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 057/202] char/mwave: fix potential Spectre v1 vulnerability In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.66-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Gustavo A. R. Silva" commit 701956d4018e5d5438570e39e8bda47edd32c489 upstream. ipcnum is 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/char/mwave/mwavedd.c:299 mwave_ioctl() warn: potential spectre issue 'pDrvData->IPCs' [w] (local cap) Fix this by sanitizing ipcnum before using it to index pDrvData->IPCs. 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 Signed-off-by: Gustavo A. R. Silva Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- drivers/char/mwave/mwavedd.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/char/mwave/mwavedd.c +++ b/drivers/char/mwave/mwavedd.c @@ -59,6 +59,7 @@ #include #include #include +#include #include "smapi.h" #include "mwavedd.h" #include "3780i.h" @@ -289,6 +290,8 @@ static long mwave_ioctl(struct file *fil ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_REGISTER_IPC" " ipcnum %x entry usIntCount %x\n", @@ -317,6 +320,8 @@ static long mwave_ioctl(struct file *fil " Invalid ipcnum %x\n", ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_GET_IPC" " ipcnum %x, usIntCount %x\n", @@ -383,6 +388,8 @@ static long mwave_ioctl(struct file *fil ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); mutex_lock(&mwave_mutex); if (pDrvData->IPCs[ipcnum].bIsEnabled == TRUE) { pDrvData->IPCs[ipcnum].bIsEnabled = FALSE;