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=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 D015DC2D0E7 for ; Thu, 26 Mar 2020 23:26:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A755A2082D for ; Thu, 26 Mar 2020 23:26:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265213; bh=1icnrn7p37qkHPzDlfJGDOpKxQZ/CgwxVjnbbBMR+l0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sNCC6a/uIUBHCz+pBg9GnjCSdJQnw+xPiLl/pmblq6soCUvPkmDlKOJQ172xKDiuN 8pmq+15k3D+V6c6pmZKHFlwvB2+//oDB/eNNcbxZCvnq3kmErl2O0rtvxIkWX2zmAC qVgFTdLT17OW2R0Gst9vFJIghyUOtVderz+7GYpA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727699AbgCZX0w (ORCPT ); Thu, 26 Mar 2020 19:26:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:45854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728216AbgCZXZK (ORCPT ); Thu, 26 Mar 2020 19:25:10 -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 BD2E420774; Thu, 26 Mar 2020 23:25:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265110; bh=1icnrn7p37qkHPzDlfJGDOpKxQZ/CgwxVjnbbBMR+l0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mewPN6wZ6AftMVqe68ubfBw9P5QjbjOMBiMpMSc7XKlM1KIEYfRVSG9zdsdMXqb/q +CR27yEmlMK9/28zKOLwgRQ4orThczosijE80PI41slLkGDN2s9pkREp+rMY6WR06S 8MuWqVOTgd0qW0cBARW77M05mZdMNJ1dRrrA/eq4= 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 4.19 13/15] ALSA: line6: Fix endless MIDI read loop Date: Thu, 26 Mar 2020 19:24:53 -0400 Message-Id: <20200326232455.8029-13-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232455.8029-1-sashal@kernel.org> References: <20200326232455.8029-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 bbcb0d4d83aec..0193d4989107b 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -320,7 +320,7 @@ 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 36a610ba342ec..c931d48801ebe 100644 --- a/sound/usb/line6/midibuf.c +++ b/sound/usb/line6/midibuf.c @@ -163,7 +163,7 @@ 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