tun: Consistently configure generic netdev params via rtnetlink
authorSerhey Popovych <serhe.popovych@gmail.com>
Tue, 9 Oct 2018 18:21:01 +0000 (21:21 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 13 Nov 2018 19:16:49 +0000 (11:16 -0800)
commit5f008fce1f275c851f62a3bf2238d5f4fc27d4dc
treed7ec76ece48a2c99c34905f51fef9cd0b31002a8
parenta2b544ef5e0fada663a565857d688f7f61b5fa27
tun: Consistently configure generic netdev params via rtnetlink

[ Upstream commit df52eab23d703142c766ac00bdb8db19d71238d0 ]

Configuring generic network device parameters on tun will fail in
presence of IFLA_INFO_KIND attribute in IFLA_LINKINFO nested attribute
since tun_validate() always return failure.

This can be visualized with following ip-link(8) command sequences:

  # ip link set dev tun0 group 100
  # ip link set dev tun0 group 100 type tun
  RTNETLINK answers: Invalid argument

with contrast to dummy and veth drivers:

  # ip link set dev dummy0 group 100
  # ip link set dev dummy0 type dummy

  # ip link set dev veth0 group 100
  # ip link set dev veth0 group 100 type veth

Fix by returning zero in tun_validate() when @data is NULL that is
always in case since rtnl_link_ops->maxtype is zero in tun driver.

Fixes: f019a7a594d9 ("tun: Implement ip link del tunXXX")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/tun.c