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From:   Phong Tran <tranmanphong@gmail.com>
To:     syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com,
        andreyknvl@google.com, hans.verkuil@cisco.com, mchehab@kernel.org,
        skhan@linuxfoundation.org, gregkh@linuxfoundation.org
Cc:     keescook@chromium.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
        syzkaller-bugs@googlegroups.com,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Phong Tran <tranmanphong@gmail.com>
Subject: [PATCH] media: usb: technisat-usb2: fix buffer overflow
Date:   Tue,  2 Jul 2019 21:02:11 +0700
Message-Id: <20190702140211.28399-1-tranmanphong@gmail.com>
In-Reply-To: <000000000000089d7f058683115e@google.com>
References: <000000000000089d7f058683115e@google.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The buffer will be overflow in case of the while loop can not break.
Add the checking buffer condition in while loop for avoiding
overlooping index.

This issue was reported by syzbot

Reported-by: syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com

Tested by:
https://groups.google.com/d/msg/syzkaller-bugs/CySBCKuUOOs/0hKq1CdjCwAJ

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
---
 drivers/media/usb/dvb-usb/technisat-usb2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/dvb-usb/technisat-usb2.c b/drivers/media/usb/dvb-usb/technisat-usb2.c
index c659e18b358b..4e0b6185666a 100644
--- a/drivers/media/usb/dvb-usb/technisat-usb2.c
+++ b/drivers/media/usb/dvb-usb/technisat-usb2.c
@@ -655,7 +655,7 @@ static int technisat_usb2_get_ir(struct dvb_usb_device *d)
 #endif
 
 	ev.pulse = 0;
-	while (1) {
+	while (b != (buf + 63)) {
 		ev.pulse = !ev.pulse;
 		ev.duration = (*b * FIRMWARE_CLOCK_DIVISOR * FIRMWARE_CLOCK_TICK) / 1000;
 		ir_raw_event_store(d->rc_dev, &ev);
-- 
2.11.0