Re: [PATCH net-next] rtnetlink: validate attributes in do_setlink()

From: Eric Dumazet <edumazet@google.com>
Date: Tue,  5 Jun 2018 09:25:19 -0700

It seems that rtnl_group_changelink() can call do_setlink
while a prior call to validate_linkmsg(dev = NULL, ...) could
not validate IFLA_ADDRESS / IFLA_BROADCAST

Make sure do_setlink() calls validate_linkmsg() instead
of letting its callers having this responsibility.

With help from Dmitry Vyukov, thanks a lot !

 ...

Fixes: e7ed828f10bd ("netlink: support setting devgroup parameters")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <redacted>

Applied and queued up for -stable.