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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Taehee Yoo <ap420073@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 15/17] macsec: avoid to set wrong mtu
Date: Thu, 30 Apr 2020 09:54:31 -0400	[thread overview]
Message-ID: <20200430135433.21204-15-sashal@kernel.org> (raw)
In-Reply-To: <20200430135433.21204-1-sashal@kernel.org>

From: Taehee Yoo <ap420073@gmail.com>

[ Upstream commit 7f327080364abccf923fa5a5b24e038eb0ba1407 ]

When a macsec interface is created, the mtu is calculated with the lower
interface's mtu value.
If the mtu of lower interface is lower than the length, which is needed
by macsec interface, macsec's mtu value will be overflowed.
So, if the lower interface's mtu is too low, macsec interface's mtu
should be set to 0.

Test commands:
    ip link add dummy0 mtu 10 type dummy
    ip link add macsec0 link dummy0 type macsec
    ip link show macsec0

Before:
    11: macsec0@dummy0: <BROADCAST,MULTICAST,M-DOWN> mtu 4294967274
After:
    11: macsec0@dummy0: <BROADCAST,MULTICAST,M-DOWN> mtu 0

Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/macsec.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index da8bf327a3e98..df2ee65a33e35 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -3209,11 +3209,11 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 			  struct nlattr *tb[], struct nlattr *data[])
 {
 	struct macsec_dev *macsec = macsec_priv(dev);
+	rx_handler_func_t *rx_handler;
+	u8 icv_len = DEFAULT_ICV_LEN;
 	struct net_device *real_dev;
-	int err;
+	int err, mtu;
 	sci_t sci;
-	u8 icv_len = DEFAULT_ICV_LEN;
-	rx_handler_func_t *rx_handler;
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
@@ -3229,7 +3229,11 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 
 	if (data && data[IFLA_MACSEC_ICV_LEN])
 		icv_len = nla_get_u8(data[IFLA_MACSEC_ICV_LEN]);
-	dev->mtu = real_dev->mtu - icv_len - macsec_extra_len(true);
+	mtu = real_dev->mtu - icv_len - macsec_extra_len(true);
+	if (mtu < 0)
+		dev->mtu = 0;
+	else
+		dev->mtu = mtu;
 
 	rx_handler = rtnl_dereference(real_dev->rx_handler);
 	if (rx_handler && rx_handler != macsec_handle_frame)
-- 
2.20.1


  parent reply	other threads:[~2020-04-30 13:57 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200430135433.21204-1-sashal@kernel.org>
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 05/17] wimax/i2400m: Fix potential urb refcnt leak Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 06/17] net: stmmac: Fix sub-second increment Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 07/17] team: fix hang in team_mode_get() Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 09/17] macvlan: fix null dereference in macvlan_device_event() Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 11/17] net: dsa: b53: Fix ARL register definitions Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 12/17] net: dsa: b53: Rework ARL bin logic Sasha Levin
2020-04-30 13:54 ` Sasha Levin [this message]
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 16/17] net: bcmgenet: suppress warnings on failed Rx SKB allocations Sasha Levin
2020-04-30 13:54 ` [PATCH AUTOSEL 4.9 17/17] net: systemport: " Sasha Levin

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