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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 DA8BEC3A59B for ; Sat, 17 Aug 2019 06:55:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B862E21019 for ; Sat, 17 Aug 2019 06:55:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726202AbfHQGze (ORCPT ); Sat, 17 Aug 2019 02:55:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:46282 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725832AbfHQGze (ORCPT ); Sat, 17 Aug 2019 02:55:34 -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 EAA70B03B; Sat, 17 Aug 2019 06:55:32 +0000 (UTC) Date: Sat, 17 Aug 2019 08:55:32 +0200 Message-ID: From: Takashi Iwai To: "Hui Peng" Cc: , , "YueHaibing" , "Thomas Gleixner" , "Mathias Payer" , "Jaroslav Kysela" , "Takashi Iwai" , "Wenwen Wang" , Subject: Re: [PATCH] Fix an OOB bug in uac_mixer_unit_bmControls In-Reply-To: <20190817043208.12433-1-benquike@gmail.com> References: <20190817043208.12433-1-benquike@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 17 Aug 2019 06:32:07 +0200, Hui Peng wrote: > > `uac_mixer_unit_get_channels` calls `uac_mixer_unit_bmControls` > to get pointer to bmControls field. The current implementation of > `uac_mixer_unit_get_channels` does properly check the size of > uac_mixer_unit_descriptor descriptor and may allow OOB access > in `uac_mixer_unit_bmControls`. > > Reported-by: Hui Peng > Reported-by: Mathias Payer > Signed-off-by: Hui Peng Ah a good catch. One easier fix in this case would be to get the offset from uac_mixer_unit_bmControls(), e.g. /* calculate the offset of bmControls field */ size_t bmc_offset = uac_mixer_unit_bmControls(NULL, protocol) - NULL; .... if (desc->bLength < bmc_offset) return 0; thanks, Takashi > --- > sound/usb/mixer.c | 25 ++++++++++++++++++------- > 1 file changed, 18 insertions(+), 7 deletions(-) > > diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c > index b5927c3d5bc0..00e6274a63c3 100644 > --- a/sound/usb/mixer.c > +++ b/sound/usb/mixer.c > @@ -738,28 +738,39 @@ static int get_cluster_channels_v3(struct mixer_build *state, unsigned int clust > static int uac_mixer_unit_get_channels(struct mixer_build *state, > struct uac_mixer_unit_descriptor *desc) > { > - int mu_channels; > + int mu_channels = 0; > void *c; > > - if (desc->bLength < sizeof(*desc)) > - return -EINVAL; > if (!desc->bNrInPins) > return -EINVAL; > - if (desc->bLength < sizeof(*desc) + desc->bNrInPins) > - return -EINVAL; > > switch (state->mixer->protocol) { > case UAC_VERSION_1: > + // limit derived from uac_mixer_unit_bmControls > + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 4) > + return 0; > + > + mu_channels = uac_mixer_unit_bNrChannels(desc); > + break; > + > case UAC_VERSION_2: > - default: > - if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 1) > + // limit derived from uac_mixer_unit_bmControls > + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 6) > return 0; /* no bmControls -> skip */ > + > mu_channels = uac_mixer_unit_bNrChannels(desc); > break; > case UAC_VERSION_3: > + // limit derived from uac_mixer_unit_bmControls > + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 2) > + return 0; /* no bmControls -> skip */ > + > mu_channels = get_cluster_channels_v3(state, > uac3_mixer_unit_wClusterDescrID(desc)); > break; > + > + default: > + break; > } > > if (!mu_channels) > -- > 2.22.1 > >