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Groups > linux.kernel > #1659090

[PATCH 09/26] signal: Don't allow sending SIGKILL or SIGSTOP to init

From "Eric W. Biederman" <ebiederm@xmission.com>
Newsgroups linux.kernel
Subject [PATCH 09/26] signal: Don't allow sending SIGKILL or SIGSTOP to init
Date 2017-06-06 21:20 +0200
Message-ID <tPsbh-4vm-47@gated-at.bofh.it> (permalink)
References <tPs1B-4ry-43@gated-at.bofh.it> <tPsbf-4vm-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Even to init SIGKILL and SIGSTOP are alwasys delivered if they are
sent, so don't allow tracing an init task allow them.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/signal.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 5eff2f9f8c42..627b482fa3f8 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -98,8 +98,12 @@ static int sig_ignored(struct task_struct *t, int sig, bool force)
 
 	/*
 	 * Tracers may want to know about even ignored signals.
+	 * We can never safely allow SIGKILL or SIGSTOP to
+	 * be sent to init from it's children.
 	 */
-	return !t->ptrace;
+	return !t->ptrace ||
+		((t->signal->flags & SIGNAL_UNKILLABLE) &&
+		 sig_kernel_only(sig) && !force);
 }
 
 /*
-- 
2.10.1

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Thread

[PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD ebiederm@xmission.com (Eric W. Biederman) - 2017-06-06 21:10 +0200
  [PATCH 01/26] alpha: Remove unused TASK_GROUP_LEADER "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 12/26] wait: Directly test for the two cases where wait_task_zombie is called "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 15/26] wait: Don't delay !ptrace_reparented leaders "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 13/26] wait: Remove unused delay_group_leader "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 17/26] exit: Rework the exit states for ptracees "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 20/26] wait: Don't pass the list to wait_consider_task "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 26/26] pidns: Ensure zap_pid_ns_processes always terminates "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 19/26] wait: Simpler code for clearing notask_error in wait_consider_task "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 24/26] signal: In ptrace_stop improve identical signal detection "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 09/26] signal: Don't allow sending SIGKILL or SIGSTOP to init "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 03/26] signal: Do not perform permission checks when sending pdeath_signal "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
      Re: [PATCH 03/26] signal: Do not perform permission checks when  sending pdeath_signal Linus Torvalds <torvalds@linux-foundation.org> - 2017-06-06 22:10 +0200
        Re: [PATCH 03/26] signal: Do not perform permission checks when sending pdeath_signal ebiederm@xmission.com (Eric W. Biederman) - 2017-06-07 13:40 +0200
      Re: [PATCH 03/26] signal: Do not perform permission checks when  sending pdeath_signal Richard Weinberger <richard.weinberger@gmail.com> - 2017-06-06 23:50 +0200
    [PATCH 07/26] pidns: Improve the error handling in alloc_pid "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 22/26] exit: Fix auto-wait of ptraced children "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 02/26] cgroup: Don't open code tasklist_empty() "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 04/26] signal: Make group_send_sig_info static "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 23/26] signal:  Fix SIGCONT before group stop completes. "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 18/26] wait: Fix WSTOPPED on a ptraced child "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 10/26] ptrace: Simplify ptrace_detach & exit_ptrace "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 21/26] wait: Optmize waitpid "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 14/26] wait: Move changing of ptrace from wait_consider_task into wait_task_stopped "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 08/26] exit: Make the runqueue rcu safe "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
      Re: [PATCH 08/26] exit: Make the runqueue rcu safe Oleg Nesterov <oleg@redhat.com> - 2017-06-07 15:20 +0200
    [PATCH 06/26] rlimit: Remove unnecessary grab of tasklist_lock "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
      Re: [PATCH 06/26] rlimit: Remove unnecessary grab of tasklist_lock Oleg Nesterov <oleg@redhat.com> - 2017-06-07 14:40 +0200
        Re: [PATCH 06/26] rlimit: Remove unnecessary grab of tasklist_lock ebiederm@xmission.com (Eric W. Biederman) - 2017-06-07 16:20 +0200
    [PATCH 16/26] exit: Fix reporting a ptraced !reparented leader has exited "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 11/26] wait: Properly implement __WCLONE handling in the presence of exec and ptrace "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 05/26] exit:  Remove the pointless clearing of SIGPENDING in __exit_signal "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:20 +0200
    [PATCH 25/26] signal: In ptrace_stop use CLD_TRAPPED in all ptrace signals "Eric W. Biederman" <ebiederm@xmission.com> - 2017-06-06 21:30 +0200
  Re: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD Aleksa Sarai <asarai@suse.de> - 2017-06-06 21:50 +0200
    Re: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD ebiederm@xmission.com (Eric W. Biederman) - 2017-06-07 13:50 +0200
      Re: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD Aleksa Sarai <asarai@suse.de> - 2017-06-07 14:30 +0200
  Re: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD Linus Torvalds <torvalds@linux-foundation.org> - 2017-06-06 22:10 +0200
    Re: [PATCH 00/26] Fixing wait, exit, ptrace, exec, and CLONE_THREAD ebiederm@xmission.com (Eric W. Biederman) - 2017-06-07 18:10 +0200

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