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 <ccfbe049-392d-4df5-5eb5-ea18576d4afd@infradead.org>
From:   Kees Cook <keescook@chromium.org>
Date:   Mon, 1 Oct 2018 21:49:37 -0700
Message-ID: <CAGXu5j+ND4K5GvxJ1ieLr5E=Zsfb6mGQL8yTegOXv4V4qmuZUA@mail.gmail.com>
Subject: Re: [PATCH security-next v4 21/32] LSM: Finalize centralized LSM
 enabling logic
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     James Morris <jmorris@namei.org>,
        Casey Schaufler <casey@schaufler-ca.com>,
        John Johansen <john.johansen@canonical.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        "Schaufler, Casey" <casey.schaufler@intel.com>,
        LSM <linux-security-module@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Mon, Oct 1, 2018 at 6:18 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
> On 10/1/18 5:54 PM, Kees Cook wrote:
>> Prior to this patch, default "enable" behavior was unchanged: SELinux
>> and AppArmor were controlled separately from the centralized control
>> defined by CONFIG_LSM_ENABLE and "lsm.enable=...". This changes the
>> logic to give all control over to the central logic.
>>
>> Instead of allowing SELinux and AppArmor to override the central LSM
>> enabling logic, by having separate CONFIG and boot parameters, this
>> forces all "enable" variables to disabled, then enables any listed in
>> the CONFIG_LSM_ENABLE and "lsm.enable=..." settings, and finally disables
>> any listed in "lsm.disable=...".
>>
>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> ---
>>  .../admin-guide/kernel-parameters.txt         |  6 ++--
>>  include/linux/lsm_hooks.h                     |  2 +-
>>  security/security.c                           | 32 +++++++------------
>>  3 files changed, 15 insertions(+), 25 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 67c90985d2b8..f646cfab5613 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -2279,14 +2279,12 @@
>>       lsm.disable=lsm1,...,lsmN
>>                       [SECURITY] Comma-separated list of LSMs to disable
>>                       at boot time. This overrides "lsm.enable=",
>
> better:                               This overrides "lsm.enable=" and

Eek, yes! Thank you. :)

-Kees

>
>> -                     CONFIG_LSM_ENABLE, and any per-LSM CONFIGs and boot
>> -                     parameters.
>> +                     CONFIG_LSM_ENABLE.
>>
>>       lsm.enable=lsm1,...,lsmN
>>                       [SECURITY] Comma-separated list of LSMs to enable
>>                       at boot time. This overrides any omissions from
>> -                     CONFIG_LSM_ENABLE, and any per-LSM CONFIGs and
>> -                     boot parameters.
>> +                     CONFIG_LSM_ENABLE.
>>
>>       machvec=        [IA-64] Force the use of a particular machine-vector
>>                       (machvec) in a generic kernel.
>
>
> --
> ~Randy


-- 
Kees Cook
Pixel Security