From: Kees Cook <keescook@chromium.org>
To: Phong Tran <tranmanphong@gmail.com>
Cc: syzbot+eaaaf38a95427be88f4b@syzkaller.appspotmail.com,
andreyknvl@google.com, hans.verkuil@cisco.com,
mchehab@kernel.org, skhan@linuxfoundation.org,
gregkh@linuxfoundation.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
Subject: Re: [PATCH] media: usb: technisat-usb2: fix buffer overflow
Date: Tue, 2 Jul 2019 09:03:05 -0700 [thread overview]
Message-ID: <201907020858.66B63B24@keescook> (raw)
In-Reply-To: <20190702140211.28399-1-tranmanphong@gmail.com>
On Tue, Jul 02, 2019 at 09:02:11PM +0700, Phong Tran wrote:
> 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)) {
This matches the "62" from the earlier read -- instead of these literal
numbers, could you replace the "62"s with a named define for whatever
would make sense for this driver (maybe "IR_MAX_EVENTS"?), and then you
can make the above be something like:
while (b <= buf + IR_MAX_EVENTS) {
> 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
>
--
Kees Cook
next prev parent reply other threads:[~2019-07-03 0:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-14 20:06 KASAN: slab-out-of-bounds Read in technisat_usb2_rc_query syzbot
2019-07-02 14:02 ` [PATCH] media: usb: technisat-usb2: fix buffer overflow Phong Tran
2019-07-02 14:23 ` Alexander Potapenko
2019-07-02 16:03 ` Kees Cook [this message]
2019-07-03 2:14 ` [PATCH V2] " Phong Tran
2019-07-03 2:26 ` Kees Cook
2019-07-03 14:52 ` [PATCH] media: technisat-usb2: break out of loop at end of buffer Sean Young
2019-07-03 16:54 ` Kees Cook
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