From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Takashi Iwai <tiwai@suse.de>, Sasha Levin <sashal@kernel.org>,
alsa-devel@alsa-project.org,
syzbot+cce32521ee0a824c21f7@syzkaller.appspotmail.com
Subject: [PATCH AUTOSEL 4.14 09/10] ALSA: line6: Fix endless MIDI read loop
Date: Thu, 26 Mar 2020 19:25:12 -0400 [thread overview]
Message-ID: <20200326232513.8212-9-sashal@kernel.org> (raw)
In-Reply-To: <20200326232513.8212-1-sashal@kernel.org>
From: Takashi Iwai <tiwai@suse.de>
[ 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: <stable@vger.kernel.org>
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 <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 b223de3defc4f..bf4eacc53a7d2 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -313,7 +313,7 @@ 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
next prev parent reply other threads:[~2020-03-26 23:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200326232513.8212-1-sashal@kernel.org>
2020-03-26 23:25 ` [PATCH AUTOSEL 4.14 02/10] ALSA: hda/realtek: Fix pop noise on ALC225 Sasha Levin
2020-03-26 23:25 ` [PATCH AUTOSEL 4.14 08/10] ALSA: pcm: oss: Avoid plugin buffer overflow Sasha Levin
2020-03-26 23:25 ` Sasha Levin [this message]
2020-03-26 23:25 ` [PATCH AUTOSEL 4.14 10/10] ALSA: pcm: oss: Remove WARNING from snd_pcm_plug_alloc() checks Sasha Levin
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