From: ebiederm@xmission.com (Eric W. Biederman)
To: Matt Bennett <matt.bennett@alliedtelesis.co.nz>
Cc: netdev@vger.kernel.org, zbr@ioremap.net,
linux-kernel@vger.kernel.org,
Linux Containers <containers@lists.linux-foundation.org>
Subject: Re: [PATCH 0/5] RFC: connector: Add network namespace awareness
Date: Thu, 02 Jul 2020 13:59:59 -0500 [thread overview]
Message-ID: <87k0zlspxs.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <20200702002635.8169-1-matt.bennett@alliedtelesis.co.nz> (Matt Bennett's message of "Thu, 2 Jul 2020 12:26:30 +1200")
Matt Bennett <matt.bennett@alliedtelesis.co.nz> writes:
> Previously the connector functionality could only be used by processes running in the
> default network namespace. This meant that any process that uses the connector functionality
> could not operate correctly when run inside a container. This is a draft patch series that
> attempts to now allow this functionality outside of the default network namespace.
>
> I see this has been discussed previously [1], but am not sure how my changes relate to all
> of the topics discussed there and/or if there are any unintended side
> effects from my draft
In a quick skim this patchset does not look like it approaches a correct
conversion to having code that works in multiple namespaces.
I will take the changes to proc_id_connector for example.
You report the values in the callers current namespaces.
Which means an unprivileged user can create a user namespace and get
connector to report whichever ids they want to users in another
namespace. AKA lie.
So this appears to make connector completely unreliable.
Eric
> changes.
>
> Thanks.
>
> [1] https://marc.info/?l=linux-kernel&m=150806196728365&w=2
>
> Matt Bennett (5):
> connector: Use task pid helpers
> connector: Use 'current_user_ns' function
> connector: Ensure callback entry is released
> connector: Prepare for supporting multiple namespaces
> connector: Create connector per namespace
>
> Documentation/driver-api/connector.rst | 6 +-
> drivers/connector/cn_proc.c | 110 +++++++-------
> drivers/connector/cn_queue.c | 9 +-
> drivers/connector/connector.c | 192 ++++++++++++++++++++-----
> drivers/hv/hv_fcopy.c | 1 +
> drivers/hv/hv_utils_transport.c | 6 +-
> drivers/md/dm-log-userspace-transfer.c | 6 +-
> drivers/video/fbdev/uvesafb.c | 8 +-
> drivers/w1/w1_netlink.c | 19 +--
> include/linux/connector.h | 38 +++--
> include/net/net_namespace.h | 4 +
> kernel/exit.c | 2 +-
> samples/connector/cn_test.c | 6 +-
> 13 files changed, 286 insertions(+), 121 deletions(-)
next prev parent reply other threads:[~2020-07-02 19:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 0:26 [PATCH 0/5] RFC: connector: Add network namespace awareness Matt Bennett
2020-07-02 0:26 ` [PATCH 1/5] connector: Use task pid helpers Matt Bennett
2020-07-02 0:26 ` [PATCH 2/5] connector: Use 'current_user_ns' function Matt Bennett
2020-07-02 0:26 ` [PATCH 3/5] connector: Ensure callback entry is released Matt Bennett
2020-07-02 0:26 ` [PATCH 4/5] connector: Prepare for supporting multiple namespaces Matt Bennett
2020-07-02 0:26 ` [PATCH 5/5] connector: Create connector per namespace Matt Bennett
2020-07-02 5:52 ` kernel test robot
2020-07-02 6:40 ` kernel test robot
2020-07-02 14:32 ` [kbuild] " Dan Carpenter
2020-07-02 13:17 ` [PATCH 0/5] RFC: connector: Add network namespace awareness Eric W. Biederman
2020-07-02 19:10 ` Christian Brauner
2020-07-02 22:44 ` Aleksa Sarai
2020-07-05 22:32 ` Matt Bennett
2020-07-13 18:34 ` Eric W. Biederman
2020-07-14 5:03 ` Aleksa Sarai
2020-07-14 5:19 ` Matt Bennett
2020-07-02 18:59 ` Eric W. Biederman [this message]
2020-07-05 22:31 ` Matt Bennett
2020-07-13 18:39 ` Eric W. Biederman
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