Fatal SIGSYS signals were not being delivered to pid namespace init
processes. Make sure the SIGNAL_UNKILLABLE doesn't get set for these
cases.
Reported-by: Robert Święcki <robert@xxxxxxxxxxx>
Suggested-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
kernel/signal.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 38602738866e..33e3ee4f3383 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1342,9 +1342,10 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
}
/*
* Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
- * debugging to leave init killable.
+ * debugging to leave init killable, unless it is intended to exit.
*/
- if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
+ if (action->sa.sa_handler == SIG_DFL &&
+ (!t->ptrace || (handler == HANDLER_EXIT)))
t->signal->flags &= ~SIGNAL_UNKILLABLE;
ret = send_signal(sig, info, t, PIDTYPE_PID);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
--
2.30.2
