[PATCH 4.18 044/135] net-ethtool: ETHTOOL_GUFO did not and should not require CAP_NET_ADMIN

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

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

From: "Maciej Åenczykowski" <maze@xxxxxxxxxx>

[ Upstream commit 474ff2600889e16280dbc6ada8bfecb216169a70 ]

So it should not fail with EPERM even though it is no longer implemented...

This is a fix for:
  (userns)$ egrep ^Cap /proc/self/status
  CapInh: 0000003fffffffff
  CapPrm: 0000003fffffffff
  CapEff: 0000003fffffffff
  CapBnd: 0000003fffffffff
  CapAmb: 0000003fffffffff

  (userns)$ tcpdump -i usb_rndis0
  tcpdump: WARNING: usb_rndis0: SIOCETHTOOL(ETHTOOL_GUFO) ioctl failed: Operation not permitted
  Warning: Kernel filter failed: Bad file descriptor
  tcpdump: can't remove kernel filter: Bad file descriptor

With this change it returns EOPNOTSUPP instead of EPERM.

See also https://github.com/the-tcpdump-group/libpcap/issues/689

Fixes: 08a00fea6de2 "net: Remove references to NETIF_F_UFO from ethtool."
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Maciej Åenczykowski <maze@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/core/ethtool.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -2623,6 +2623,7 @@ int dev_ethtool(struct net *net, struct
 	case ETHTOOL_GPHYSTATS:
 	case ETHTOOL_GTSO:
 	case ETHTOOL_GPERMADDR:
+	case ETHTOOL_GUFO:
 	case ETHTOOL_GGSO:
 	case ETHTOOL_GGRO:
 	case ETHTOOL_GFLAGS: