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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 987A7C4707E for ; Thu, 14 Apr 2022 15:23:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356931AbiDNPZH (ORCPT ); Thu, 14 Apr 2022 11:25:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347033AbiDNN6M (ORCPT ); Thu, 14 Apr 2022 09:58:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0F6AB6D0D; Thu, 14 Apr 2022 06:48:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C7757B82894; Thu, 14 Apr 2022 13:48:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23212C385A5; Thu, 14 Apr 2022 13:48:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649944112; bh=ZK9bnx/lyZZ9oKvnCjW+4Ll2OOuQv7jyiZ83Vdpi3Bg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FbveaBUe/ZLxe0sxPrTSBp6agJw0KfmnTbtwFeS2gZeTgrjRIpmf0gDVzdSPxfqRv ypia2xduVR++Da7QA5x5dOoWv45VEpB8GSHoTnGlbISthsnFqg0vzsVrMYsYu6gq3p 6xli96TH/iYW6nB1XeNjZ1OkLVuHEzTSwlYvFHT8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jordy Zomer , Mike Snitzer , Sasha Levin Subject: [PATCH 5.4 391/475] dm ioctl: prevent potential spectre v1 gadget Date: Thu, 14 Apr 2022 15:12:56 +0200 Message-Id: <20220414110906.014386562@linuxfoundation.org> X-Mailer: git-send-email 2.35.2 In-Reply-To: <20220414110855.141582785@linuxfoundation.org> References: <20220414110855.141582785@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jordy Zomer [ Upstream commit cd9c88da171a62c4b0f1c70e50c75845969fbc18 ] It appears like cmd could be a Spectre v1 gadget as it's supplied by a user and used as an array index. Prevent the contents of kernel memory from being leaked to userspace via speculative execution by using array_index_nospec. Signed-off-by: Jordy Zomer Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- drivers/md/dm-ioctl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 3f15d8dc2b71..7a73f2fa0ad7 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -17,6 +17,7 @@ #include #include #include +#include #include @@ -1696,6 +1697,7 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) if (unlikely(cmd >= ARRAY_SIZE(_ioctls))) return NULL; + cmd = array_index_nospec(cmd, ARRAY_SIZE(_ioctls)); *ioctl_flags = _ioctls[cmd].flags; return _ioctls[cmd].fn; } -- 2.35.1