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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Oliver Neukum <oneukum@suse.com>,
        Johan Hovold <johan@kernel.org>,
        syzbot+d29e9263e13ce0b9f4fd@syzkaller.appspotmail.com
Subject: [PATCH 4.19 23/48] USB: serial: garmin_gps: add sanity checking for data length
Date:   Wed, 13 May 2020 11:44:49 +0200
Message-Id: <20200513094356.758557175@linuxfoundation.org>
In-Reply-To: <20200513094351.100352960@linuxfoundation.org>
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From: Oliver Neukum <oneukum@suse.com>

commit e9b3c610a05c1cdf8e959a6d89c38807ff758ee6 upstream.

We must not process packets shorter than a packet ID

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reported-and-tested-by: syzbot+d29e9263e13ce0b9f4fd@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/serial/garmin_gps.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -1138,8 +1138,8 @@ static void garmin_read_process(struct g
 		   send it directly to the tty port */
 		if (garmin_data_p->flags & FLAGS_QUEUING) {
 			pkt_add(garmin_data_p, data, data_length);
-		} else if (bulk_data ||
-			   getLayerId(data) == GARMIN_LAYERID_APPL) {
+		} else if (bulk_data || (data_length >= sizeof(u32) &&
+				getLayerId(data) == GARMIN_LAYERID_APPL)) {
 
 			spin_lock_irqsave(&garmin_data_p->lock, flags);
 			garmin_data_p->flags |= APP_RESP_SEEN;