Messages in this thread | | | Date | Wed, 29 Apr 2009 10:29:06 +1000 (EST) | From | James Morris <> | Subject | Re: Q: selinux_bprm_committed_creds() && signals/do_wait |
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On Wed, 29 Apr 2009, Oleg Nesterov wrote:
> selinux_bprm_committed_creds: > > rc = avc_has_perm() > if (rc) { > flush_signals(current); > > This doesn't look right. If the task was SIGKILL'ed we must not proceed, > the task should die. The fix is simple, we should check SIGNAL_GROUP_EXIT > and do nothing in this case, the task will exit before return to user > space. If SIGNAL_GROUP_EXIT is set, it is just wrong to drop SIGKILL and > continue.
I'm not quite sure what you're asking. This is a permission check to see if the new task can inherit the signal state of the parent, and if not, the new task's signal state is flushed.
Where does a consideration of SIGKILL arise?
> But, before fixing, I'd like to understand why we are doing > > flush_signal_handlers(current, 1); > sigemptyset(¤t->blocked); > > later. Could someone explain ? This looks unneeded.
This is part of clearing all the signal state in the child.
> > > Another question, > > wake_up_interruptible(¤t->parent->signal->wait_chldexit); > > Shouldn't we use ->real_parent ? Afaics, we shouldn't worry about the tracer > if current is ptraced, exec must not succeed if the tracer has no rights to > trace this task after cred changing. But we should notify ->real_parent which > is, well, real parent. > > Also, we don't need _irq to take tasklist_lock, and we don't actually need > ->siglock. > > Oleg. >
-- James Morris <jmorris@namei.org>
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