linux-kernel - [PATCH v2 0/4] xen: harden netfront against malicious backends

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Date:   Tue, 24 Aug 2021 12:28:05 +0200
From:   Juergen Gross <jgross@...e.com>
To:     xen-devel@...ts.xenproject.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH v2 0/4] xen: harden netfront against malicious backends

Xen backends of para-virtualized devices can live in dom0 kernel, dom0
user land, or in a driver domain. This means that a backend might
reside in a less trusted environment than the Xen core components, so
a backend should not be able to do harm to a Xen guest (it can still
mess up I/O data, but it shouldn't be able to e.g. crash a guest by
other means or cause a privilege escalation in the guest).

Unfortunately netfront in the Linux kernel is fully trusting its
backend. This series is fixing netfront in this regard.

It was discussed to handle this as a security problem, but the topic
was discussed in public before, so it isn't a real secret.

It should be mentioned that a similar series has been posted some years
ago by Marek Marczykowski-Górecki, but this series has not been applied
due to a Xen header not having been available in the Xen git repo at
that time. Additionally my series is fixing some more DoS cases.

Changes in V2:
- put netfront patches into own series
- comments addressed
- new patch 3

Juergen Gross (4):
  xen/netfront: read response from backend only once
  xen/netfront: don't read data from request on the ring page
  xen/netfront: disentangle tx_skb_freelist
  xen/netfront: don't trust the backend response data blindly

 drivers/net/xen-netfront.c | 272 +++++++++++++++++++++++--------------
 1 file changed, 169 insertions(+), 103 deletions(-)

-- 
2.26.2