Re: [RFC][PATCH] 'kill sig -1' must only apply to callers namespace

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org writes:

>>From d92b4befe07c6a1e852e4462126a5443342448cd Mon Sep 17 00:00:00 2001
> From: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Date: Tue, 21 Oct 2008 18:00:01 -0700
> Subject: [PATCH] kill sig -1 must only apply to callers namespace
>
> Currently "kill <sig> -1" kills processes in all namespaces and breaks the
> isolation of namespaces. Earlier attempt to fix this is discussed at:
>
> 	http://lkml.org/lkml/2008/7/23/148
>
> but nothing seems to have happened since then.

Ugh.  I thought that conversation had resolved the problem and gotten
a patch in.

This patch works because pid_vnr returns 0 for processes outside of
the current pid namespace.

> This patch uses the simple fix suggested by Oleg Nesterov.
>
> Signed-off-by: Sukadev Bhattiprolu <sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>

Acked-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>


> ---
>  kernel/signal.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 105217d..4530fc6 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1144,7 +1144,8 @@ static int kill_something_info(int sig, struct siginfo
> *info, pid_t pid)
>  		struct task_struct * p;
>  
>  		for_each_process(p) {
> -			if (p->pid > 1 && !same_thread_group(p, current)) {
> +			if (task_pid_vnr(p) > 1 &&
> +					!same_thread_group(p, current)) {
>  				int err = group_send_sig_info(sig, info, p);
>  				++count;
>  				if (err != -EPERM)
> -- 
> 1.5.2.5