netdev - [PATCH v2 net-next] ethtool: ignore unused/unreliable fields in set

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Message-ID: <ad7ee11e-eb7a-4975-9122-547e13a161d8@gmail.com>
Date: Sat, 2 Mar 2024 15:18:27 +0100
From: Heiner Kallweit <hkallweit1@...il.com>
To: Andrew Lunn <andrew@...n.ch>,
 Russell King - ARM Linux <linux@...linux.org.uk>,
 Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
 David Miller <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH v2 net-next] ethtool: ignore unused/unreliable fields in
 set_eee op

This function is used with the set_eee() ethtool operation. Certain
fields of struct ethtool_keee() are relevant only for the get_eee()
operation. In addition, in case of the ioctl interface, we have no
guarantee that userspace sends sane values in struct ethtool_eee.
Therefore explicitly ignore all fields not needed for set_eee().
This protects from drivers trying to use unchecked and unreliable
data, relying on specific userspace behavior.

Note: Such unsafe driver behavior has been found and fixed in the
tg3 driver.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
v2:
- rebased
---
 net/ethtool/ioctl.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 317308bdb..5a55270aa 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1514,17 +1514,12 @@ static void eee_to_keee(struct ethtool_keee *keee,
 {
 	memset(keee, 0, sizeof(*keee));
 
-	keee->eee_active = eee->eee_active;
 	keee->eee_enabled = eee->eee_enabled;
 	keee->tx_lpi_enabled = eee->tx_lpi_enabled;
 	keee->tx_lpi_timer = eee->tx_lpi_timer;
 
-	ethtool_convert_legacy_u32_to_link_mode(keee->supported,
-						eee->supported);
 	ethtool_convert_legacy_u32_to_link_mode(keee->advertised,
 						eee->advertised);
-	ethtool_convert_legacy_u32_to_link_mode(keee->lp_advertised,
-						eee->lp_advertised);
 }
 
 static void keee_to_eee(struct ethtool_eee *eee,
-- 
2.44.0