Re: [Ksummit-discuss] [TECH TOPIC] seccomp

[Christian Brauner <christian@brauner.io>]

On July 20, 2019 9:23:33 AM GMT+02:00, James Morris <jmorris@namei.org> wrote:
>On Fri, 19 Jul 2019, Christian Brauner wrote:
>
>> There is a close connection between 1. and 2. When a watcher
>intercepts
>> a syscall from a watchee and starts to inspect its arguments it can -
>> depending on the syscall rather often actually - determine whether or
>> not the syscall would succeed or fail. If it knows that the syscall
>will
>> succeed it currently still has to perform it in lieu of the watchee
>> since there is no way to tell the kernel to "resume" or actually
>perform
>> the syscall. It would be nice if we could discuss approaches to
>enabling
>> this feature as well.
>
>Landlock is exploring userspace access control via the seccomp 
>syscall with ebpf, but from within the same process:
>
>https://landlock.io/
>
>It may be worth investigating whether Landlock could be extended to a 
>split watcher/watchee model.

Certainly a valid point but...
I don't want to rely on landlock for this.
First, no one knows if and when it will ever land.
Second, seccomp is the go-to sandboxing solution for a lot of userspace already.
Often used without a full LSM.
Third, syscall interception to me is seccomp territory. :)
That's to say I'd like seccomp to have this feature *natively* and ideally not tied to
a complete LSM that needs to be merged for this. :)

Christian