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=-10.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 B00FFC43331 for ; Thu, 26 Mar 2020 23:35:14 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3874F20663 for ; Thu, 26 Mar 2020 23:35:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="PwQRDLI8"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qxX1vHcJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3874F20663 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 94A141671; Fri, 27 Mar 2020 00:34:22 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 94A141671 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1585265712; bh=BlfqdZa54NDq3OfYObDAkxKzjq23kbgBb8WXlxx7bxU=; h=From:To:Subject:Date:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=PwQRDLI8NIrFSnxBZs7nRW4HCPXAyhenfqTuWsdooimmjN1JRfKN0k4x4dIozQie8 nvF+JinaViFa+y+3JmJOxNKLp3jr3y9VdWrExRNSrQrv5xkZqhC/LiYMhgCDhQzq2k qKyAngjvNKo9lKMBucUpJVb1I7PnwivfbCeIqkWw= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 863D7F8033D; Fri, 27 Mar 2020 00:25:39 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id E92B8F80345; Fri, 27 Mar 2020 00:25:37 +0100 (CET) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 10FA1F8033D for ; Fri, 27 Mar 2020 00:25:35 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 10FA1F8033D Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qxX1vHcJ" 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 11B8920774; Thu, 26 Mar 2020 23:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265133; bh=BlfqdZa54NDq3OfYObDAkxKzjq23kbgBb8WXlxx7bxU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qxX1vHcJK+w4gKVK9dJDKBYljjUwEA2uaWX6zs77oGd+7qdCfEhYddErsY7hWQA9n 72bThoDco2GZzG9x059lU8loWsMJB+Lte8ynWKqxS72nqHu9qcXuWvxXuDJe5gUgZE su0pZzhEnaAu3bWYDhLrv4zFCiQASJRgaEA63yqY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 6/7] ALSA: line6: Fix endless MIDI read loop Date: Thu, 26 Mar 2020 19:25:25 -0400 Message-Id: <20200326232526.8349-6-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232526.8349-1-sashal@kernel.org> References: <20200326232526.8349-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Cc: Takashi Iwai , Sasha Levin , alsa-devel@alsa-project.org, syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" 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 09189249d0d19..ea3a9bd05e687 100644 --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -306,7 +306,7 @@ 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