Messages in this thread Patch in this message | | | Date | Thu, 1 Dec 2022 15:40:15 -0800 | From | Kees Cook <> | Subject | Re: [PATCH] signal: Initialize the info in ksignal |
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On Mon, Nov 28, 2022 at 06:56:06AM +0000, haifeng.xu wrote: > When handing the SIGNAL_GROUP_EXIT flag, the info in ksignal isn't cleared. > However, the info acquired by dequeue_synchronous_signal/dequeue_signal is > initialized and can be safely used. Fortunately, the fatal signal process > just uses the si_signo and doesn't use any other member. Even so, the > initialization before use is more safer.
Yeah, this patch seems correct -- get_signal() is usually called with an uninitialized stack variable, and normally goes through dequeue_* helpers which do a copy. The fatal path doesn't.
-Kees
> Signed-off-by: haifeng.xu <haifeng.xu@shopee.com> > --- > kernel/signal.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/signal.c b/kernel/signal.c > index d140672185a4..b9b0c8c620e7 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -2693,6 +2693,7 @@ bool get_signal(struct ksignal *ksig) > /* Has this task already been marked for death? */ > if ((signal->flags & SIGNAL_GROUP_EXIT) || > signal->group_exec_task) { > + clear_siginfo(&ksig->info); > ksig->info.si_signo = signr = SIGKILL; > sigdelset(¤t->pending.signal, SIGKILL); > trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO, > -- > 2.25.1 >
-- Kees Cook
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