From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kees Cook" <keescook@chromium.org>,
"Robert Święcki" <robert@swiecki.net>,
stable@vger.kernel.org, "Andy Lutomirski" <luto@amacapital.net>,
"Will Drewry" <wad@chromium.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH 1/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE
Date: Wed, 9 Feb 2022 18:53:19 -0800 [thread overview]
Message-ID: <20220210025321.787113-2-keescook@chromium.org> (raw)
In-Reply-To: <20220210025321.787113-1-keescook@chromium.org>
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@swiecki.net>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
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
next prev parent reply other threads:[~2022-02-10 2:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-10 2:53 [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE Kees Cook
2022-02-10 2:53 ` Kees Cook [this message]
2022-02-10 16:18 ` [PATCH 1/3] " Jann Horn
2022-02-10 17:37 ` Kees Cook
2022-02-10 18:01 ` Jann Horn
2022-02-10 18:12 ` Eric W. Biederman
2022-02-10 21:09 ` Kees Cook
2022-02-11 20:15 ` Jann Horn
2022-02-10 18:16 ` Eric W. Biederman
2022-02-10 2:53 ` [PATCH 2/3] seccomp: Invalidate seccomp mode to catch death failures Kees Cook
2022-02-10 2:53 ` [PATCH 3/3] samples/seccomp: Adjust sample to also provide kill option Kees Cook
2022-02-10 18:17 ` [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE Eric W. Biederman
2022-02-10 18:41 ` Kees Cook
2022-02-10 18:58 ` Eric W. Biederman
2022-02-10 20:43 ` Kees Cook
2022-02-10 22:48 ` Eric W. Biederman
2022-02-11 1:26 ` Kees Cook
2022-02-11 1:47 ` Eric W. Biederman
2022-02-11 2:53 ` Kees Cook
2022-02-11 12:54 ` Robert Święcki
2022-02-11 17:46 ` Eric W. Biederman
2022-02-11 18:57 ` Robert Święcki
2022-02-11 20:01 ` Kees Cook
2022-02-11 19:58 ` Kees Cook
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