From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Brian Silverman <brian.silverman@bluerivertech.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH 5.15 33/41] can: gs_usb: gs_can_start_xmit(): zero-initialize hf->{flags,reserved}
Date:   Fri, 14 Jan 2022 09:16:33 +0100
Message-Id: <20220114081546.268378329@linuxfoundation.org>
In-Reply-To: <20220114081545.158363487@linuxfoundation.org>
References: <20220114081545.158363487@linuxfoundation.org>
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From: Brian Silverman <brian.silverman@bluerivertech.com>

commit 89d58aebe14a365c25ba6645414afdbf4e41cea4 upstream.

No information is deliberately sent in hf->flags in host -> device
communications, but the open-source candleLight firmware echoes it
back, which can result in the GS_CAN_FLAG_OVERFLOW flag being set and
generating spurious ERRORFRAMEs.

While there also initialize the reserved member with 0.

Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://lore.kernel.org/all/20220106002952.25883-1-brian.silverman@bluerivertech.com
Link: https://github.com/candle-usb/candleLight_fw/issues/87
Cc: stable@vger.kernel.org
Signed-off-by: Brian Silverman <brian.silverman@bluerivertech.com>
[mkl: initialize the reserved member, too]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/can/usb/gs_usb.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -508,6 +508,8 @@ static netdev_tx_t gs_can_start_xmit(str
 
 	hf->echo_id = idx;
 	hf->channel = dev->channel;
+	hf->flags = 0;
+	hf->reserved = 0;
 
 	cf = (struct can_frame *)skb->data;