[PATCH for v4.9 LTS 24/86] net: ethtool: Initialize buffer when querying device channel settings

[Levin, Alexander (Sasha Levin)]

From: Eran Ben Elisha <eranbe@xxxxxxxxxxxx>

[ Upstream commit 31a86d137219373c3222ca5f4f912e9a4d8065bb ]

Ethtool channels respond struct was uninitialized when querying device
channel boundaries settings. As a result, unreported fields by the driver
hold garbage.  This may cause sending unsupported params to driver.

Fixes: 8bf368620486 ('ethtool: ensure channel counts are within bounds ...')
Signed-off-by: Eran Ben Elisha <eranbe@xxxxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
CC: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 net/core/ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 072c1f4998c9..e9989b835a66 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1704,7 +1704,7 @@ static noinline_for_stack int ethtool_get_channels(struct net_device *dev,
 static noinline_for_stack int ethtool_set_channels(struct net_device *dev,
 						   void __user *useraddr)
 {
-	struct ethtool_channels channels, max;
+	struct ethtool_channels channels, max = { .cmd = ETHTOOL_GCHANNELS };
 	u32 max_rx_in_use = 0;
 
 	if (!dev->ethtool_ops->set_channels || !dev->ethtool_ops->get_channels)
-- 
2.11.0