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Date:   Mon, 23 Mar 2020 21:20:08 -0700 (PDT)
Message-Id: <20200323.212008.1786774265459415637.davem@davemloft.net>
To:     mkubecek@suse.cz
Cc:     kuba@kernel.org, netdev@vger.kernel.org, johannes@sipsolutions.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v2] netlink: check for null extack in cookie helpers
From:   David Miller <davem@davemloft.net>
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From: Michal Kubecek <mkubecek@suse.cz>
Date: Sat, 21 Mar 2020 00:46:50 +0100 (CET)

> Unlike NL_SET_ERR_* macros, nl_set_extack_cookie_u64() and
> nl_set_extack_cookie_u32() helpers do not check extack argument for null
> and neither do their callers, as syzbot recently discovered for
> ethnl_parse_header().
> 
> Instead of fixing the callers and leaving the trap in place, add check of
> null extack to both helpers to make them consistent with NL_SET_ERR_*
> macros.
> 
> v2: drop incorrect second Fixes tag
> 
> Fixes: 2363d73a2f3e ("ethtool: reject unrecognized request flags")
> Reported-by: syzbot+258a9089477493cea67b@syzkaller.appspotmail.com
> Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

Applied, thanks Michal.