netdev - nf_conntrack: Infoleak via CTA_ID and CTA_EXPECT

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Message-ID: <c84e0301-2bb6-8932-2ed5-939340762159@nod.at>
Date:   Fri, 30 Jun 2017 21:25:15 +0200
From:   Richard Weinberger <richard@....at>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     Pablo Neira Ayuso <pablo@...filter.org>, fw@...len.de,
        David Miller <davem@...emloft.net>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        David Gstir <david@...ma-star.at>, kaber@...sh.net,
        "keescook@...omium.org" <keescook@...omium.org>
Subject: nf_conntrack: Infoleak via CTA_ID and CTA_EXPECT_ID

Hi!

I noticed that nf_conntrack leaks kernel addresses, it uses the memory address
as identifier used for generating conntrack and expect ids..
Since these ids are also visible to unprivileged users via network namespaces
I suggest reverting these commits:

commit 7f85f914721ffcef382a57995182916bd43d8a65
Author: Patrick McHardy <kaber@...sh.net>
Date:   Fri Sep 28 14:41:27 2007 -0700

    [NETFILTER]: nf_conntrack: kill unique ID

    Remove the per-conntrack ID, its not necessary anymore for dumping.
    For compatiblity reasons we send the address of the conntrack to
    userspace as ID.

    Signed-off-by: Patrick McHardy <kaber@...sh.net>
    Signed-off-by: David S. Miller <davem@...emloft.net>

commit 3583240249ef354760e04ae49bd7b462a638f40c
Author: Patrick McHardy <kaber@...sh.net>
Date:   Fri Sep 28 14:41:50 2007 -0700

    [NETFILTER]: nf_conntrack_expect: kill unique ID

    Similar to the conntrack ID, the per-expectation ID is not needed
    anymore, kill it.

    Signed-off-by: Patrick McHardy <kaber@...sh.net>
    Signed-off-by: David S. Miller <davem@...emloft.net>

Thanks,
//richard