netdev - [PATCH] net-ethtool: ETHTOOL_GUFO did not and should not require CAP_NET

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Message-Id: <20180922083401.12131-1-zenczykowski@gmail.com>
Date:   Sat, 22 Sep 2018 01:34:01 -0700
From:   "Maciej Żenczykowski" <zenczykowski@...il.com>
To:     "Maciej Żenczykowski" <maze@...gle.com>,
        "David S . Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org
Subject: [PATCH] net-ethtool: ETHTOOL_GUFO did not and should not require CAP_NET_ADMIN

From: Maciej Żenczykowski <maze@...gle.com>

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@...emloft.net>
Signed-off-by: Maciej Żenczykowski <maze@...gle.com>
---
 net/core/ethtool.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 9d4e56d97080..96afc55aa61e 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -2536,6 +2536,7 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
 	case ETHTOOL_GPHYSTATS:
 	case ETHTOOL_GTSO:
 	case ETHTOOL_GPERMADDR:
+	case ETHTOOL_GUFO:
 	case ETHTOOL_GGSO:
 	case ETHTOOL_GGRO:
 	case ETHTOOL_GFLAGS:
-- 
2.19.0.444.g18242da7ef-goog