Messages in this thread | | | Date | Wed, 24 Dec 2008 16:55:29 +0100 | From | Oleg Nesterov <> | Subject | Re: [RFC][PATCH 7/7][v4] SI_TKILL: Masquerade si_pid when crossing pid ns boundary |
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On 12/24, Sukadev Bhattiprolu wrote: > > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -2385,17 +2385,22 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig) > struct siginfo info; > struct task_struct *p; > unsigned long flags; > + struct pid_namespace *ns; > > error = -ESRCH; > info.si_signo = sig; > info.si_errno = 0; > info.si_code = SI_TKILL; > - info.si_pid = task_tgid_vnr(current); > info.si_uid = current_uid(); > > rcu_read_lock(); > p = find_task_by_vpid(pid); > if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { > + ns = task_active_pid_ns(p); > + if (ns) > + info.si_pid = task_tgid_nr_ns(current, ns); > + else > + info.si_pid = task_tgid_vnr(current);
if ns == 0, "p" won't see the signal anyway, so all we need is
- info.si_pid = task_tgid_vnr(current); + info.si_pid = task_tgid_nr_ns(current, task_active_ns(p));
like we do in __do_notify().
But. this of course doesn't work for sys_kill(). Can't we change the helpers which send SI_FROMUSER() signals so that they do not fill .si_pid at all? Then send_signal() can do:
default: copy_siginfo(&q->info, info); info.si_pid = 0; if (!from_ancestot_ns) info.si_pid = task_tgid_nr_ns(current, ...);
?
Yes, we use "current". But we already used it in siginfo_from_ancestor_ns().
Oleg.
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