4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" ebiederm@xmission.com
[ Upstream commit 3597dfe01d12f570bc739da67f857fd222a3ea66 ]
Instead of playing whack-a-mole and changing SEND_SIG_PRIV to SEND_SIG_FORCED throughout the kernel to ensure a pid namespace init gets signals sent by the kernel, stop allowing a pid namespace init to ignore SIGKILL or SIGSTOP sent by the kernel. A pid namespace init is only supposed to be able to ignore signals sent from itself and children with SIG_DFL.
Fixes: 921cf9f63089 ("signals: protect cinit from unblocked SIG_DFL signals") Reviewed-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/signal.c +++ b/kernel/signal.c @@ -1009,7 +1009,7 @@ static int __send_signal(int sig, struct
result = TRACE_SIGNAL_IGNORED; if (!prepare_signal(sig, t, - from_ancestor_ns || (info == SEND_SIG_FORCED))) + from_ancestor_ns || (info == SEND_SIG_PRIV) || (info == SEND_SIG_FORCED))) goto ret;
pending = group ? &t->signal->shared_pending : &t->pending;