Re: [PATCH v2 1/2] security, lsm: Introduce security_mptcp_add_subflow()

[Paul Moore]

On Apr 20, 2023 Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx> wrote:
> 
> MPTCP can create subflows in kernel context, and later indirectly
> expose them to user-space, via the owning MPTCP socket.
> 
> As discussed in the reported link, the above causes unexpected failures
> for server, MPTCP-enabled applications.
> 
> Let's introduce a new LSM hook to allow the security module to relabel
> the subflow according to the owning user-space process, via the MPTCP
> socket owning the subflow.
> 
> Note that the new hook requires both the MPTCP socket and the new
> subflow. This could allow future extensions, e.g. explicitly validating
> the MPTCP <-> subflow linkage.
> 
> Link: https://lore.kernel.org/mptcp/CAHC9VhTNh-YwiyTds=P1e3rixEDqbRTFj22bpya=+qJqfcaMfg@xxxxxxxxxxxxxx/
> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
> Acked-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
> Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
> ---
> v2:
>  - Address Paul's comments:
>    - clarification around "the owning process" in the commit message
>    - making it clear the hook has to be called after the sk init part
>    - consistent capitalization of "MPTCP"
> ---
>  include/linux/lsm_hook_defs.h |  1 +
>  include/linux/security.h      |  6 ++++++
>  net/mptcp/subflow.c           |  6 ++++++
>  security/security.c           | 17 +++++++++++++++++
>  4 files changed, 30 insertions(+)

This looks good to me, merged into selinux/next - thank you for all
the work that went into this!

--
paul-moore.com