Messages in this thread | | | Subject | Re: Kernel stack read with PTRACE_EVENT_EXIT and io_uring threads | From | Michael Schmitz <> | Date | Wed, 23 Jun 2021 09:48:40 +1200 |
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Hi Eric,
On 23/06/21 9:02 am, Eric W. Biederman wrote: > Linus Torvalds <torvalds@linux-foundation.org> writes: > > So I was more thinking of the debug patch for m68k to catch all the > _regular_ cases, and all the other random cases of ptrace_event() or > ptrace_notify(). > > Although maybe we've really caught them all. The exit case was clearly > missing, and the thread fork case was scrogged. There are patches for > the known problems. The patches I really don't like are the > verification ones to find any unknown ones.. > We still have nios2 which copied the m68k logic at some point. I think > that is a processor that is still ``shipping'' and that people might > still be using in new designs. > > I haven't looked closely enough to see what the other architectures with > caller saved registers are doing. > > The challenging ones are /proc/pid/syscall and seccomp which want to see > all of the system call arguments. I think every architecture always > saves the system call arguments unconditionally, so those cases are > probably not as interesting. But they certain look like they could be > trouble.
Seccomp hasn't yet been implemented on m68k, though I'm working on that with Adrian. The sole secure_computing() call will happen in syscall_trace_enter(), so all system call arguments have been saved on the stack.
Haven't looked at /proc/pid/syscall yet ...
Cheers,
Michael
> Eric >
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