Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 017/209] can: rx-offload: can_rx_offload_queue_tail(): fix error handling, avoid skb mem leak
Date:   Wed,  4 Dec 2019 18:53:49 +0100
Message-Id: <20191204175322.733225494@linuxfoundation.org>
In-Reply-To: <20191204175321.609072813@linuxfoundation.org>
References: <20191204175321.609072813@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Marc Kleine-Budde <mkl@pengutronix.de>

[ Upstream commit 6caf8a6d6586d44fd72f4aa1021d14aa82affafb ]

If the rx-offload skb_queue is full can_rx_offload_queue_tail() will not
queue the skb and return with an error.

This patch frees the skb in case of a full queue, which brings
can_rx_offload_queue_tail() in line with the
can_rx_offload_queue_sorted() function, which has been adjusted in the
previous patch.

The return value is adjusted to -ENOBUFS to better reflect the actual
problem.

The device stats handling is left to the caller.

Fixes: d254586c3453 ("can: rx-offload: Add support for HW fifo based irq offloading")
Reported-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/can/rx-offload.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/rx-offload.c b/drivers/net/can/rx-offload.c
index 1a7c183e66783..b26987a136203 100644
--- a/drivers/net/can/rx-offload.c
+++ b/drivers/net/can/rx-offload.c
@@ -261,8 +261,10 @@ int can_rx_offload_queue_tail(struct can_rx_offload *offload,
 			      struct sk_buff *skb)
 {
 	if (skb_queue_len(&offload->skb_queue) >
-	    offload->skb_queue_len_max)
-		return -ENOMEM;
+	    offload->skb_queue_len_max) {
+		kfree_skb(skb);
+		return -ENOBUFS;
+	}
 
 	skb_queue_tail(&offload->skb_queue, skb);
 	can_rx_offload_schedule(offload);
-- 
2.20.1