From patchwork Thu Jul 4 14:48:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 11031571 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0DEC2112C for ; Thu, 4 Jul 2019 14:48:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E5E5F28837 for ; Thu, 4 Jul 2019 14:48:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D570728A97; Thu, 4 Jul 2019 14:48:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 55C7C28837 for ; Thu, 4 Jul 2019 14:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727392AbfGDOsS (ORCPT ); Thu, 4 Jul 2019 10:48:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:45634 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727066AbfGDOsS (ORCPT ); Thu, 4 Jul 2019 10:48:18 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7C4C9AEE1; Thu, 4 Jul 2019 14:48:16 +0000 (UTC) From: Takashi Iwai To: alsa-devel@alsa-project.org Cc: Stefan Sauer , Greg Kroah-Hartman , linux-usb@vger.kernel.org Subject: [PATCH] ALSA: usb-audio: Fix parse of UAC2 Extension Units Date: Thu, 4 Jul 2019 16:48:06 +0200 Message-Id: <20190704144806.30513-1-tiwai@suse.de> X-Mailer: git-send-email 2.16.4 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Extension Unit (XU) is used to have a compatible layout with Processing Unit (PU) on UAC1, and the usb-audio driver code assumed it for parsing the descriptors. Meanwhile, on UAC2, XU became slightly incompatible with PU; namely, XU has a one-byte bmControls bitmap while PU has two bytes bmControls bitmap. This incompatibility results in the read of a wrong address for the last iExtension field, which ended up with an incorrect string for the mixer element name, as recently reported for Focusrite Scarlett 18i20 device. This patch corrects the present misalignment by introducing a couple of new macros and calling them depending on the descriptor type. Reported-by: Stefan Sauer Cc: Signed-off-by: Takashi Iwai --- include/uapi/linux/usb/audio.h | 37 +++++++++++++++++++++++++++++++++++++ sound/usb/mixer.c | 16 ++++++++++------ 2 files changed, 47 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/usb/audio.h b/include/uapi/linux/usb/audio.h index ddc5396800aa..76b7c3f6cd0d 100644 --- a/include/uapi/linux/usb/audio.h +++ b/include/uapi/linux/usb/audio.h @@ -450,6 +450,43 @@ static inline __u8 *uac_processing_unit_specific(struct uac_processing_unit_desc } } +/* + * Extension Unit (XU) has almost compatible layout with Processing Unit, but + * on UAC2, it has a different bmControls size (bControlSize); it's 1 byte for + * XU while 2 bytes for PU. The last iExtension field is a one-byte index as + * well as iProcessing field of PU. + */ +static inline __u8 uac_extension_unit_bControlSize(struct uac_processing_unit_descriptor *desc, + int protocol) +{ + switch (protocol) { + case UAC_VERSION_1: + return desc->baSourceID[desc->bNrInPins + 4]; + case UAC_VERSION_2: + return 1; /* in UAC2, this value is constant */ + case UAC_VERSION_3: + return 4; /* in UAC3, this value is constant */ + default: + return 1; + } +} + +static inline __u8 uac_extension_unit_iExtension(struct uac_processing_unit_descriptor *desc, + int protocol) +{ + __u8 control_size = uac_extension_unit_bControlSize(desc, protocol); + + switch (protocol) { + case UAC_VERSION_1: + case UAC_VERSION_2: + default: + return *(uac_processing_unit_bmControls(desc, protocol) + + control_size); + case UAC_VERSION_3: + return 0; /* UAC3 does not have this field */ + } +} + /* 4.5.2 Class-Specific AS Interface Descriptor */ struct uac1_as_header_descriptor { __u8 bLength; /* in bytes: 7 */ diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index e003b5e7b01a..ac121b10c51c 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -2318,7 +2318,7 @@ static struct procunit_info extunits[] = { */ static int build_audio_procunit(struct mixer_build *state, int unitid, void *raw_desc, struct procunit_info *list, - char *name) + bool extension_unit) { struct uac_processing_unit_descriptor *desc = raw_desc; int num_ins; @@ -2335,6 +2335,8 @@ static int build_audio_procunit(struct mixer_build *state, int unitid, static struct procunit_info default_info = { 0, NULL, default_value_info }; + const char *name = extension_unit ? + "Extension Unit" : "Processing Unit"; if (desc->bLength < 13) { usb_audio_err(state->chip, "invalid %s descriptor (id %d)\n", name, unitid); @@ -2448,7 +2450,10 @@ static int build_audio_procunit(struct mixer_build *state, int unitid, } else if (info->name) { strlcpy(kctl->id.name, info->name, sizeof(kctl->id.name)); } else { - nameid = uac_processing_unit_iProcessing(desc, state->mixer->protocol); + if (extension_unit) + nameid = uac_extension_unit_iExtension(desc, state->mixer->protocol); + else + nameid = uac_processing_unit_iProcessing(desc, state->mixer->protocol); len = 0; if (nameid) len = snd_usb_copy_string_desc(state->chip, @@ -2481,10 +2486,10 @@ static int parse_audio_processing_unit(struct mixer_build *state, int unitid, case UAC_VERSION_2: default: return build_audio_procunit(state, unitid, raw_desc, - procunits, "Processing Unit"); + procunits, false); case UAC_VERSION_3: return build_audio_procunit(state, unitid, raw_desc, - uac3_procunits, "Processing Unit"); + uac3_procunits, false); } } @@ -2495,8 +2500,7 @@ static int parse_audio_extension_unit(struct mixer_build *state, int unitid, * Note that we parse extension units with processing unit descriptors. * That's ok as the layout is the same. */ - return build_audio_procunit(state, unitid, raw_desc, - extunits, "Extension Unit"); + return build_audio_procunit(state, unitid, raw_desc, extunits, true); } /*