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,USER_AGENT_GIT autolearn=unavailable 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 580F3C43331 for ; Thu, 26 Mar 2020 23:28:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27DD52083E for ; Thu, 26 Mar 2020 23:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265335; bh=E3QsCnsuUDRRo8kdeYSkq2UO7hjxNljMU6+avIz5qQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Gl7DOTWtObBxM6drRkdKZXHQ8PunntGa1V/RqyOFIQOjYve4vIJkcmCH50tLfb70U npNNfrTvvIfSxWuA8VZsdZnk0PI3BaRhnhVcf2MVaFm/MXlVvHIp9jlgGtGD3dNVMd DDqnakz8asIzk54j5WD1P3EBCY+PpzOjn1NWnGe0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728352AbgCZX2x (ORCPT ); Thu, 26 Mar 2020 19:28:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:44086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727835AbgCZXY1 (ORCPT ); Thu, 26 Mar 2020 19:24:27 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 F0EB420409; Thu, 26 Mar 2020 23:24:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265066; bh=E3QsCnsuUDRRo8kdeYSkq2UO7hjxNljMU6+avIz5qQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f5WPdLBsy6h7BQt+qrRdVU1aNVvd7qzF3xq54JymKqeP/jGkgudyFYArb/PioMYFj 2nSCx3wUlqewRytnrJ2UsoF4xaEZWAbe6byj2lqeBdGu2pGBGIIVPzi1523PP+TckC F0tJ6Rpv/HGilCuv6o+ivpA/W84o9S1vr/PxiD/E= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com, Sasha Levin , alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 5.5 25/28] ALSA: line6: Fix endless MIDI read loop Date: Thu, 26 Mar 2020 19:23:54 -0400 Message-Id: <20200326232357.7516-25-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232357.7516-1-sashal@kernel.org> References: <20200326232357.7516-1-sashal@kernel.org> MIME-Version: 1.0 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: Takashi Iwai [ Upstream commit d683469b3c93d7e2afd39e6e1970f24700eb7a68 ] The MIDI input event parser of the LINE6 driver may enter into an endless loop when the unexpected data sequence is given, as it tries to continue the secondary bytes without termination. Also, when the input data is too short, the parser returns a negative error, while the caller doesn't handle it properly. This would lead to the unexpected behavior as well. This patch addresses those issues by checking the return value correctly and handling the one-byte event in the parser properly. The bug was reported by syzkaller. Reported-by: syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com Cc: Link: https://lore.kernel.org/r/000000000000033087059f8f8fa3@google.com Link: https://lore.kernel.org/r/20200309095922.30269-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/usb/line6/driver.c | 2 +- sound/usb/line6/midibuf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c index b5a3f754a4f13..4f096685ed654 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -305,7 +305,7 @@ static void line6_data_received(struct urb *urb) line6_midibuf_read(mb, line6->buffer_message, LINE6_MIDI_MESSAGE_MAXLEN); - if (done == 0) + if (done <= 0) break; line6->message_length = done; diff --git a/sound/usb/line6/midibuf.c b/sound/usb/line6/midibuf.c index 8d6eefa0d9362..6a70463f82c4e 100644 --- a/sound/usb/line6/midibuf.c +++ b/sound/usb/line6/midibuf.c @@ -159,7 +159,7 @@ int line6_midibuf_read(struct midi_buffer *this, unsigned char *data, int midi_length_prev = midibuf_message_length(this->command_prev); - if (midi_length_prev > 0) { + if (midi_length_prev > 1) { midi_length = midi_length_prev - 1; repeat = 1; } else -- 2.20.1