Re: [RFC v2] ptrace, pidfd: add pidfd_ptrace syscall

[Hagen Paul Pfeifer <hagen@jauu.net>]

* Linus Torvalds | 2020-04-27 21:28:14 [-0700]:

>> I hate to say this, but I’m not convinced that asking the gdb folks is
>> the right approach. GDB has an ancient architecture and is
>> *incredibly* buggy. I’m sure ptrace is somewhere on the pain point
>> list, but I suspect it’s utterly dwarfed by everything else.
>
>You may be right. However, if gdbn isn't going to use it, then I
>seriously don't think it's worth changing much.
>
>It might be worth looking at people who don't use ptrace() for
>debugging, but for "incidental" reasons. IOW sandboxing, tracing,
>things like that.
>
>Maybe those people want things that are simpler and don't actually
>need the kinds of hard serialization that ptrace() wants.
>
>I'd rather add a few really simple things that might not be a full
>complement of operations for a debugger, but exactly because they
>aren't a full debugger, maybe they are things that we can tell are
>obviously secure and simple?

Okay, to sum up the the whole discussion: we go forward with Jann's proposal
by simple adding PTRACE_ATTACH_PIDFD and friends. This is the minimal invasive
solution and the risk of an potenial security problem is almost not present[TM].

Changing the whole ptrace API is a different beast. I rather believe that I
see Linus Linux successor rather than a ptrace successor.

I am fine with PTRACE_ATTACH_PIDFD!

Hagen