From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:58980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755391AbeD3TZ5 (ORCPT ); Mon, 30 Apr 2018 15:25:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Takashi Iwai Subject: [PATCH 4.4 28/44] ALSA: hda: Hardening for potential Spectre v1 Date: Mon, 30 Apr 2018 12:24:39 -0700 Message-Id: <20180430190947.463498343@linuxfoundation.org> In-Reply-To: <20180430190946.093694747@linuxfoundation.org> References: <20180430190946.093694747@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 69fa6f19b95597618ab30438a27b67ad93daa7c7 upstream. As recently Smatch suggested, one place in HD-audio hwdep ioctl codes may expand the array directly from the user-space value with speculation: sound/pci/hda/hda_local.h:467 get_wcaps() warn: potential spectre issue 'codec->wcaps' As get_wcaps() itself is a fairly frequently called inline function, and there is only one single call with a user-space value, we replace only the latter one to open-code locally with array_index_nospec() hardening in this patch. BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2 Reported-by: Dan Carpenter Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/pci/hda/hda_hwdep.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/sound/pci/hda/hda_hwdep.c +++ b/sound/pci/hda/hda_hwdep.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include "hda_codec.h" #include "hda_local.h" @@ -51,7 +52,16 @@ static int get_wcap_ioctl(struct hda_cod if (get_user(verb, &arg->verb)) return -EFAULT; - res = get_wcaps(codec, verb >> 24); + /* open-code get_wcaps(verb>>24) with nospec */ + verb >>= 24; + if (verb < codec->core.start_nid || + verb >= codec->core.start_nid + codec->core.num_nodes) { + res = 0; + } else { + verb -= codec->core.start_nid; + verb = array_index_nospec(verb, codec->core.num_nodes); + res = codec->wcaps[verb]; + } if (put_user(res, &arg->res)) return -EFAULT; return 0;