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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, Sean Tranchetti <stranche@codeaurora.org>,
        Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 044/143] net: qualcomm: rmnet: Skip processing loopback packets
Date:   Fri,  2 Nov 2018 19:33:49 +0100
Message-Id: <20181102182900.574196542@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit a07f388e2cde2be74b263f85df6f672fea0305a1 ]

RMNET RX handler was processing invalid packets that were
originally sent on the real device and were looped back via
dev_loopback_xmit(). This was detected using syzkaller.

Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 929fb8d96ec0..8d979fef5fc7 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
@@ -205,6 +205,9 @@ rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
 	if (!skb)
 		return RX_HANDLER_CONSUMED;
 
+	if (skb->pkt_type == PACKET_LOOPBACK)
+		return RX_HANDLER_PASS;
+
 	dev = skb->dev;
 	port = rmnet_get_port(dev);
 
-- 
2.17.1