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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 9FA60C54FCF for ; Tue, 24 Mar 2020 13:31:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6942720753 for ; Tue, 24 Mar 2020 13:31:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585056701; bh=Zh6Q81xz4S7Uy/uL5Zghtt2qm145iElh7QjBAawbpiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zFoODgxjBmi740+jpqeo89g5+YN6iEg+7Amtm7ZkwLpc9XFLG1h7wTaARVrFDNm7Q 5+Hl6tzx093bZLn8IyxdCvyUbrvgpm3ISzXSvvzXa7dlnDFJGJCl62YhwO88OT2dhM PCiquj8uaVyUDq2C+ABjlWqsl63kasXdxNHk9NaE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727282AbgCXNTj (ORCPT ); Tue, 24 Mar 2020 09:19:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:40390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728617AbgCXNTg (ORCPT ); Tue, 24 Mar 2020 09:19:36 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 32A2620775; Tue, 24 Mar 2020 13:19:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055975; bh=Zh6Q81xz4S7Uy/uL5Zghtt2qm145iElh7QjBAawbpiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n0hiXq1J9EMue4iEkcyN0wdpx8FhvLi40mh8hNnSyeg2XlZ0a7jPW2haeJ1oMeCpH JFE00XCZSFLJ+8QD7o1Y866EvgFgKY2RTUSWWhmAwaRp8NSWKcYjOReN5Jly1hmlq4 iKKUoKpRoy/1Zp69Qqt+szWlbh5hH9AdLvWab3G4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 5.4 047/102] ALSA: line6: Fix endless MIDI read loop Date: Tue, 24 Mar 2020 14:10:39 +0100 Message-Id: <20200324130811.517312000@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324130806.544601211@linuxfoundation.org> References: <20200324130806.544601211@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit d683469b3c93d7e2afd39e6e1970f24700eb7a68 upstream. 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: Greg Kroah-Hartman --- sound/usb/line6/driver.c | 2 +- sound/usb/line6/midibuf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -305,7 +305,7 @@ static void line6_data_received(struct u line6_midibuf_read(mb, line6->buffer_message, LINE6_MIDI_MESSAGE_MAXLEN); - if (done == 0) + if (done <= 0) break; line6->message_length = done; --- a/sound/usb/line6/midibuf.c +++ b/sound/usb/line6/midibuf.c @@ -159,7 +159,7 @@ int line6_midibuf_read(struct midi_buffe 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