On Wed, Sep 14, 2016 at 6:19 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> On Wed, Sep 14, 2016 at 3:14 PM, Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
>>
>> On 14/09/2016 20:29, Andy Lutomirski wrote:
>>> On Wed, Sep 14, 2016 at 12:24 AM, Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
>>>> This third origin of hook call should cover all possible trigger paths
>>>> (e.g. page fault). Landlock eBPF programs can then take decisions
>>>> accordingly.
>>>>
>>>> Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
>>>> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
>>>> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
>>>> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
>>>> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
>>>> ---
>>>
>>>
>>>>
>>>> + if (unlikely(in_interrupt())) {
>>>
>>> IMO security hooks have no business being called from interrupts.
>>> Aren't they all synchronous things done by tasks? Interrupts are
>>> driver things.
>>>
>>> Are you trying to check for page faults and such?
>>
>> Yes, that was the idea you did put in my mind. Not sure how to deal with
>> this.
>>
>
> It's not so easy, unfortunately. The easiest reliable way might be to
> set a TS_ flag on all syscall entries when TIF_SECCOMP or similar is
> set.
For making this series smaller, let's leave the idea idea of interrupt
hooks out -- the intention is for stricter syscall filtering, yes?
Once things are more well established and there's a use-case for this,
it can be added back in.
-Kees
--
Kees Cook
Nexus Security
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