[PATCH v39 02/42] SM: Infrastructure management of the sock security

[Casey Schaufler]

On 6/21/2024 1:31 PM, Paul Moore wrote:
> On Fri, Dec 15, 2023 at 5:18 PM Casey Schaufler <casey at schaufler-ca.com> wrote:
>> Move management of the sock->sk_security blob out
>> of the individual security modules and into the security
>> infrastructure. Instead of allocating the blobs from within
>> the modules the modules tell the infrastructure how much
>> space is required, and the space is allocated there.
>>
>> Acked-by: Paul Moore <paul at paul-moore.com>
>> Reviewed-by: Kees Cook <keescook at chromium.org>
>> Reviewed-by: John Johansen <john.johansen at canonical.com>
>> Acked-by: Stephen Smalley <stephen.smalley.work at gmail.com>
>> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
>> ---
>>  include/linux/lsm_hooks.h         |  1 +
>>  security/apparmor/include/net.h   |  3 +-
>>  security/apparmor/lsm.c           | 20 +-------
>>  security/apparmor/net.c           |  2 +-
>>  security/security.c               | 36 ++++++++++++++-
>>  security/selinux/hooks.c          | 76 ++++++++++++++-----------------
>>  security/selinux/include/objsec.h |  5 ++
>>  security/selinux/netlabel.c       | 23 +++++-----
>>  security/smack/smack.h            |  5 ++
>>  security/smack/smack_lsm.c        | 70 ++++++++++++++--------------
>>  security/smack/smack_netfilter.c  |  4 +-
>>  11 files changed, 131 insertions(+), 114 deletions(-)
> I had to do some minor merge fixups, but I just merged this into the
> lsm/dev-staging branch to do some testing, assuming all goes well I'll
> move this over to the lsm/dev branch; I'll send another note if/when
> that happens.
>
> One of the things that has bothered me about the LSM framework is the
> inconsistency around allocation and management of the LSM security
> blobs (the `void *security` fields present in many kernel objects).
> In some cases the framework itself manages these fields, in other
> cases it is left up to the individual LSMs; while there are reasons
> for this (move to the framework on an as-needed basis), it is a little
> odd and with any inconsistency I worry about the potential for bugs.
> I think moving the allocation and management of all the LSM blobs into
> the LSM framework, similar to what was done here with the sock's
> sk_security field, would be a Very Good Thing and help bring some
> additional consistency to the LSM interfaces.  Looking quickly at only
> the SELinux code, I see six additional blobs that would need to be
> converted; it's possible there are others in use by other LSMs, but I
> haven't checked.
>
> Casey, is this something you would be interested in pursuing or would
> you rather I give it a shot?

I'm happy to do it. Would you like a separate patch set for this, or
should I add it to the stacking mega-set?