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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2D425C3A5A1 for ; Thu, 22 Aug 2019 17:17:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EEF0F2089E for ; Thu, 22 Aug 2019 17:17:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494278; bh=xXQt8UGofUcuwu2F6gVS6aa86ztULV+z4Wq+Gjv1c0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ivgT2yHqfCYaIyLtddDf9m9HnNpbuihBoXocnPLEO3gBjFCuGmBDxsLWcAuy4+AOd aXYYlrjvAeeK2xxVSyUPxXiatHZw6oXQJF4nWVgyJn8mX9JULXkVZRClooqFRXdHlo SRfI24Pmpw5xHek1Blrk6j8gZcq8l5NoZIJHnhrk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389593AbfHVRRx (ORCPT ); Thu, 22 Aug 2019 13:17:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:58028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390308AbfHVRIZ (ORCPT ); Thu, 22 Aug 2019 13:08:25 -0400 Received: from sasha-vm.mshome.net (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 614872341D; Thu, 22 Aug 2019 17:08:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566493704; bh=xXQt8UGofUcuwu2F6gVS6aa86ztULV+z4Wq+Gjv1c0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YTFmOhqKy6jCmTOAgjPPKHbmA7mhNUMzQQuLz93raEeoDXVL5qAPAL6TfMdc2RtZZ 704vshF38/qvispwpkT/EjQVGXrG0QleuM4kZVcMy2U0IB1Rhx8pK+llZU0TR/P5k2 ihPHbpYbs5jnVaA923to5ZMB+5XvJ8XVaqn8yUSE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Hui Peng , Mathias Payer , Takashi Iwai , Greg Kroah-Hartman Subject: [PATCH 5.2 018/135] ALSA: usb-audio: Fix a stack buffer overflow bug in check_input_term Date: Thu, 22 Aug 2019 13:06:14 -0400 Message-Id: <20190822170811.13303-19-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190822170811.13303-1-sashal@kernel.org> References: <20190822170811.13303-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.2.10-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.2.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.2.10-rc1 X-KernelTest-Deadline: 2019-08-24T17:07+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hui Peng commit 19bce474c45be69a284ecee660aa12d8f1e88f18 upstream. `check_input_term` recursively calls itself with input from device side (e.g., uac_input_terminal_descriptor.bCSourceID) as argument (id). In `check_input_term`, if `check_input_term` is called with the same `id` argument as the caller, it triggers endless recursive call, resulting kernel space stack overflow. This patch fixes the bug by adding a bitmap to `struct mixer_build` to keep track of the checked ids and stop the execution if some id has been checked (similar to how parse_audio_unit handles unitid argument). Reported-by: Hui Peng Reported-by: Mathias Payer Signed-off-by: Hui Peng Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/mixer.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 7498b5191b68e..2051a64fa2904 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -68,6 +68,7 @@ struct mixer_build { unsigned char *buffer; unsigned int buflen; DECLARE_BITMAP(unitbitmap, MAX_ID_ELEMS); + DECLARE_BITMAP(termbitmap, MAX_ID_ELEMS); struct usb_audio_term oterm; const struct usbmix_name_map *map; const struct usbmix_selector_map *selector_map; @@ -773,16 +774,25 @@ static int uac_mixer_unit_get_channels(struct mixer_build *state, * parse the source unit recursively until it reaches to a terminal * or a branched unit. */ -static int check_input_term(struct mixer_build *state, int id, +static int __check_input_term(struct mixer_build *state, int id, struct usb_audio_term *term) { int protocol = state->mixer->protocol; int err; void *p1; + unsigned char *hdr; memset(term, 0, sizeof(*term)); - while ((p1 = find_audio_control_unit(state, id)) != NULL) { - unsigned char *hdr = p1; + for (;;) { + /* a loop in the terminal chain? */ + if (test_and_set_bit(id, state->termbitmap)) + return -EINVAL; + + p1 = find_audio_control_unit(state, id); + if (!p1) + break; + + hdr = p1; term->id = id; if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) { @@ -800,7 +810,7 @@ static int check_input_term(struct mixer_build *state, int id, /* call recursively to verify that the * referenced clock entity is valid */ - err = check_input_term(state, d->bCSourceID, term); + err = __check_input_term(state, d->bCSourceID, term); if (err < 0) return err; @@ -834,7 +844,7 @@ static int check_input_term(struct mixer_build *state, int id, case UAC2_CLOCK_SELECTOR: { struct uac_selector_unit_descriptor *d = p1; /* call recursively to retrieve the channel info */ - err = check_input_term(state, d->baSourceID[0], term); + err = __check_input_term(state, d->baSourceID[0], term); if (err < 0) return err; term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */ @@ -897,7 +907,7 @@ static int check_input_term(struct mixer_build *state, int id, /* call recursively to verify that the * referenced clock entity is valid */ - err = check_input_term(state, d->bCSourceID, term); + err = __check_input_term(state, d->bCSourceID, term); if (err < 0) return err; @@ -948,7 +958,7 @@ static int check_input_term(struct mixer_build *state, int id, case UAC3_CLOCK_SELECTOR: { struct uac_selector_unit_descriptor *d = p1; /* call recursively to retrieve the channel info */ - err = check_input_term(state, d->baSourceID[0], term); + err = __check_input_term(state, d->baSourceID[0], term); if (err < 0) return err; term->type = UAC3_SELECTOR_UNIT << 16; /* virtual type */ @@ -964,7 +974,7 @@ static int check_input_term(struct mixer_build *state, int id, return -EINVAL; /* call recursively to retrieve the channel info */ - err = check_input_term(state, d->baSourceID[0], term); + err = __check_input_term(state, d->baSourceID[0], term); if (err < 0) return err; @@ -982,6 +992,15 @@ static int check_input_term(struct mixer_build *state, int id, return -ENODEV; } + +static int check_input_term(struct mixer_build *state, int id, + struct usb_audio_term *term) +{ + memset(term, 0, sizeof(*term)); + memset(state->termbitmap, 0, sizeof(state->termbitmap)); + return __check_input_term(state, id, term); +} + /* * Feature Unit */ -- 2.20.1