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SubjectRe: [PATCH] user namespace: make signal.c respect user namespaces
Quoting Oleg Nesterov (oleg@redhat.com):
> On 09/23, Serge E. Hallyn wrote:
> >
> > It looks like I can fix all the
> > cases
>
> except ptrace_signal(). Although we can simply ignore this case, imho.

ptrace_signal() calls send_signal() though.

But oh, dear. It is sending a signal on behalf of the parent, so what I was
about to send, which does the uid mapping at send_signal() using current_cred()
as the id to send, is not correct.

Which unfortunately means that I'll have to have the caller of send_signal
(when doing SI_USER) either send the signal sender's cred, or do the
mapping. Or special-case ptrace_signal(). This is not as pretty as I'd
hoped.

> > at send_signal()
>
> Yes, I was thinking about this too but didn't have the time to check
> if this can really work.
>
> > by checking whether si_fromuser(info)
>
> I am not sure... sys_rt_queueinfo() is nasty. Plus we have to handle
> the "fromkernel" case too. May be we can ignore this too.

sys_rt_tgsigqueueinfo() still seems to go through send_signal().

thanks,
-serge


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