net-ethtool: ETHTOOL_GUFO did not and should not require CAP_NET_ADMIN
authorMaciej Żenczykowski <maze@google.com>
Sat, 22 Sep 2018 08:34:01 +0000 (01:34 -0700)
committerDavid S. Miller <davem@davemloft.net>
Sun, 23 Sep 2018 00:11:26 +0000 (17:11 -0700)
commit474ff2600889e16280dbc6ada8bfecb216169a70
tree9c85a5ceb0482e6f98751ecb4b9ae7f29427bde0
parent8360ed6745df6de2d8ddff8e2116789258fe5890
net-ethtool: ETHTOOL_GUFO did not and should not require CAP_NET_ADMIN

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@davemloft.net>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/ethtool.c